Power transmission device, control method for power transmission device, and storage medium

Abstract

A power transmission device (100), which wirelessly transmits power to a power reception device (200), detects an object by transmitting analog Ping. A power transmitting device (100) transmits a digital Ping, and a power receiving device (200) is activated for communication. A power transmission device (100) determines the strength of electromagnetic coupling between a power transmission antenna and a power reception antenna using a plurality of analog Ping or digital Ping having different conditions. When the electromagnetic coupling between the two antennas is identified to be weak; a power transmission device (100) performs control for suppressing noise leaking from an antenna to the surroundings, control for suppressing instability of communication between the power transmission device (100) and a power reception device (200), and control for suppressing deterioration of detection accuracy of an object located between the power transmission device (100) and the power reception device (200).

Description

Technical Field

[0001] The present disclosure relates to a power transmission device for wireless power transmission, a control method of the power transmission device, a storage medium, and the like. Background Art

[0002] In a wireless power transmission system, a power transmission device transmits power to a power receiving device placed on a charging base or the like. Usually, wireless power transmission is performed in a state where a power transmission antenna provided in the power transmission device and a power receiving antenna provided in the power receiving device face each other. Patent document 1 discloses a process for detecting a foreign object that has entered between a power transmission coil and a power receiving coil, and a process for detecting a positional deviation between the power transmission coil and the power receiving coil.

[0003] Citation List

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-38509 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] In the conventional technology, there is no established method for performing appropriate control when the electromagnetic coupling between the power transmitting antenna and the power receiving antenna is weak during wireless power transmission from the power transmitting device to the power receiving device. The case where the electromagnetic coupling (hereinafter simply referred to as coupling) between the power transmitting antenna and the power receiving antenna is weak includes a case where the power receiving antenna and the power transmitting antenna are not directly facing each other, and a case where the distance between the power receiving antenna and the power transmitting antenna is greater than or equal to a predetermined distance, etc.

[0008] An object of the present disclosure is to provide a technology for enabling control corresponding to the electromagnetic coupling state between a power transmitting antenna and a power receiving antenna in wireless power transmission.

[0009] Solutions for solving problems

[0010] According to the present disclosure, there is provided a power transmitting device, comprising: a power transmitting component configured to wirelessly transmit power to a power receiving device via a power transmitting antenna; a detection component configured to detect an object by utilizing the power transmitting device to output a signal under a plurality of different conditions; and a control component configured to control the power transmitting component, wherein, when the detection component detects the power receiving device and the electromagnetic coupling between the power transmitting antenna and the power receiving antenna of the power receiving device is weaker than the electromagnetic coupling in a predetermined state, the control component changes a process for controlling the power transmitting component.

[0011] Effects of the Invention

[0012] According to the present disclosure, it is possible to provide a technology for enabling control corresponding to the electromagnetic coupling state between a power transmitting antenna and a power receiving antenna in wireless power transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a diagram showing an example of a configuration of a wireless power transmission system.

[0014] Figure 2 is a diagram showing an example of the configuration of a power transmission device.

[0015] Figure 3 is a diagram showing an example of the configuration of a power receiving device.

[0016] Figure 4 This is an explanatory diagram of a threshold setting method for state detection using a power loss method.

[0017] Figure 5 (A) and (B) are diagrams for explaining the Q value measurement method.

[0018] Figure 6 : is a block diagram showing an example of a functional configuration of a control unit of a power transmitting device.

[0019] Figure 7 This is a flowchart for explaining the processing of the power transmitting device.

[0020] Figure 8 is a flowchart for explaining the processing of the power receiving device.

[0021] Fig. 9 This is an explanatory diagram of state detection based on the waveform decay method.

[0022] Fig.10 is a diagram illustrating an example of a process for performing wireless power transmission.

[0023] Fig.11 It is an explanatory diagram of a threshold value setting method for state detection based on the waveform decay method.

[0024] Fig.12 (A) and (B) are diagrams for explaining a method for measuring an index of a coupling state between a power transmitting antenna and a power receiving antenna.

[0025] Fig.13 This is an explanatory diagram of a threshold setting method for state detection based on the coupling state index measurement method.

[0026] Fig.14 (A) to (D) are explanatory diagrams of the coupling state between the power transmitting antenna and the power receiving antenna.

[0027] Fig.15(A) and (B) are explanatory diagrams of examples of Ping transmission in the first embodiment.

[0028] Fig.16 is an explanatory sequence diagram of an example of the operation according to the first embodiment.

[0029] Fig.17 1 is a flowchart for explaining the processing of the power transmitting device in the first embodiment.

[0030] Fig.18 (A) and (B) are explanatory diagrams of another example of Ping transmission in the first embodiment.

[0031] Fig.19 (A) and (B) are explanatory diagrams of another example of Ping transmission in the first embodiment.

[0032] Fig. 20 is an explanatory sequence diagram of an example of the operation in the first embodiment.

[0033] Fig.21 1 is a flowchart for explaining the processing of the power transmitting device in the first embodiment.

[0034] Fig. 22 (A) to (C) are explanatory diagrams of another example of Ping transmission in the first embodiment.

[0035] Fig.23 is an explanatory sequence diagram of an example of the operation in the first embodiment.

[0036] Fig.24 1 is a flowchart for explaining the processing of the power transmitting device in the first embodiment.

[0037] Fig.25 yes Fig.24 Illustrative flow chart of the processing that follows.

[0038] Fig.26 is an explanatory flowchart of the processing in the first method of the second embodiment.

[0039] Fig. 27 is an explanatory flowchart of the processing in the second method of the second embodiment.

[0040] Fig.28 is an explanatory flowchart of the processing in the third method of the second embodiment.

[0041] Fig.29 is an explanatory flowchart of another example of the processing in the third method of the second embodiment. DETAILED DESCRIPTION

[0042] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. In the embodiment, a wireless charging system to which a wireless power transmission system is applied will be described. As an example, wireless power transmission based on a standard (hereinafter referred to as the WPC standard) established by a wireless charging standardization organization called the Wireless Power Alliance will be described.

[0043] [First embodiment]

[0044] Will refer to Figures 1 to 25 This embodiment is described. Figure 1 is a diagram showing an example of a configuration of a wireless charging system.

[0045] The system includes a power transmitting device 100, a power receiving device 200, and a charging base 300. Hereinafter, for the sake of brevity, the power receiving device 200 may be referred to as RX, and the power transmitting device 100 may be referred to as TX. Figure 2 and Figure 3 Describes the detailed configuration of TX and RX.

[0046] The RX is an electronic device that receives power from the TX and charges a built-in battery in a state where the RX is placed on the charging base 300. The TX is an electronic device that wirelessly transmits power to the RX placed on the charging base 300.

[0047] Since the charging base 300 constitutes a part of the TX, hereinafter, the state in which the RX is “placed on the charging base 300” may be the state in which the RX is “placed on the TX”. Figure 1 , the range of the dashed box 400 schematically shows the spatial range in which the RX can receive power from the TX.

[0048] RX and TX may have functions for executing applications other than the wireless charging function. For example, RX is a smart phone and TX is an accessory device for charging the battery of RX. However, the present disclosure is not limited to this example.

[0049] Next, we will refer to Figure 2 An example of the configuration of the power transmitting device 100 is described. Figure 2 1 is a functional block diagram showing an example of the configuration of a power transmission device 100 (TX). TX includes a control unit 101, a power supply unit 102, a power transmission unit 103, a first communication unit 104, a power transmission antenna (power transmission coil) 105, a memory 106, a resonant capacitor 107, a switch unit 108, a second communication unit 109, and a user interface unit 110.

[0050] In the following, the user interface is referred to as UI. Figure 2 Each functional block element is recorded as a separate entity, but any number of functional block elements can be implemented in the same chip.

[0051] The control unit 101 controls the entire TX by executing a control program stored in the memory 106. In addition, the control unit 101 performs power transmission control including communication for device authentication in TX.

[0052] In addition, the control unit 101 may perform control for executing applications other than wireless power transmission. The control unit 101 is configured to include one or more processors such as a central processing unit (CPU) and a microprocessor unit (MPU).

[0053] Alternatively, the control unit 101 may include hardware such as an application specific integrated circuit (ASIC) or the like.

[0054] In addition, the control unit 101 may be configured to include an array circuit such as a field programmable gate array (FPGA) programmed to perform predetermined processing. The control unit 101 may perform a process of storing information to be stored in the memory 106 during execution of various types of processing or a time measurement process using a timer (not shown).

[0055] The power supply unit 102 supplies power to each functional block element. The power supply unit 102 includes, for example, a power supply connection circuit to a commercial power source and a battery. The battery is charged with power supplied from the commercial power source.

[0056] The power transmission unit 103 converts the DC power or AC power input from the power supply unit 102 into AC power of a frequency band used in wireless power transmission, and inputs the AC power to the power transmission antenna 105, thereby generating electromagnetic waves for the RX to receive power.

[0057] For example, the power transmission unit 103 includes an inverter and converts the DC voltage supplied from the power supply unit 102 into an AC voltage in a switching circuit having a half-bridge configuration or a full-bridge configuration. The power transmission unit 103 includes a plurality of field effect transistors (FETs) constituting a bridge and a gate driver configured to control ON / OFF of the plurality of FETs.

[0058] The power transmission unit 103 controls the intensity of the electromagnetic waves to be output (transmission power) by adjusting the voltage (transmission voltage) or current (transmission current) or both input to the power transmission antenna 105. The intensity of the electromagnetic waves (intensity of the transmission power) is controlled by the magnitude of the transmission voltage or the transmission current.

[0059] Alternatively, the power transmission unit 103 controls the intensity of electromagnetic waves to be output (transmission power) by adjusting the voltage or current or both input to an inverter having the power transmission unit 103 .

[0060] The voltage input to the inverter is hereinafter referred to as the inverter input voltage. The current input to the inverter is hereinafter referred to as the inverter input current. The strength of the electromagnetic wave (strength of the transmitted power) is controlled by the magnitude of the inverter input voltage or the inverter input current.

[0061] Alternatively, the power transmission unit 103 controls the intensity of electromagnetic waves to be output (transmission power) by adjusting the voltage or current or both output from an inverter of the power transmission unit 103. The voltage output from the inverter is hereinafter referred to as inverter output voltage.

[0062] In addition, the current output from the inverter is hereinafter referred to as the inverter output current. The intensity of the electromagnetic wave (the intensity of the transmitted power) is controlled by the magnitude of the inverter output voltage or the inverter output current.

[0063] In the power transmission unit 103, the power transmission unit 103 starts or stops the power transmission through the power transmission antenna 105 based on the instruction signal from the control unit 101, or controls the output of the power of the electromagnetic wave of the AC frequency so as to control the intensity of the electromagnetic wave to be output. In addition, it is assumed that the power transmission unit 103 has a charging unit ( Figure 3 :206) Power supply capability to output 15 watts (W) of power.

[0064] The first communication unit 104 is connected to the control unit 101 and the power transmission unit 103, and communicates with the RX for power transmission control based on the WPC standard. The first communication unit 104 performs frequency shift modulation on the electromagnetic wave output from the power transmission antenna 105, transmits information to the RX, and communicates.

[0065] Furthermore, the first communication unit 104 demodulates the electromagnetic wave transmitted from the power transmission antenna 105 modulated by RX and acquires the information transmitted by RX. The communication of the first communication unit 104 is performed by superimposing a communication signal on the electromagnetic wave transmitted from the power transmission antenna 105.

[0066] In addition to the control program, the memory 106 may also store information related to the status of TX and RX. The information related to the status of TX and RX includes the value of the power transmission and the value of the power reception. The information related to the status of TX is acquired by the control unit 101. The information related to the status of RX can be acquired by the control unit of RX ( Figure 3 :201) is obtained and received by the first communication unit 104 or the second communication unit 109 to be described below.

[0067] The switch unit 108 is connected in parallel to the series circuit of the resonance capacitor 107 and the power transmission antenna 105. The control unit 101 transmits a control signal to the switch unit 108 to perform ON / OFF control thereof.

[0068] The power transmitting antenna 105 is connected to the resonance capacitor 107. When the switch unit 108 is turned on and short-circuited due to a control signal from the control unit 101, the power transmitting antenna 105 and the resonance capacitor 107 form a series resonance circuit and resonate at a specific frequency fA.

[0069] At this time, current flows through a closed circuit formed by the power transmission antenna 105, the resonance capacitor 107, and the switch unit 108. On the other hand, when the switch unit 108 is turned off by a control signal from the control unit 101 and the relevant circuit is open, power is supplied from the power transmission unit 103 to the power transmission antenna 105 and the resonance capacitor 107.

[0070] The second communication unit 109 is connected to the control unit 101 and communicates with the RX using a standard different from the WPC standard. For example, the second communication unit 109 communicates with the RX using an antenna different from the power transmission antenna 105. Figure 3 The second communication unit 212 in the communication.

[0071] Examples include wireless local area network (LAN), Bluetooth (registered trademark) low energy (BLE), and near field communication (NFC). The frequency band used when power is transmitted from the power transmission antenna 105 is different from the frequency band used in communication by the second communication unit 109 .

[0072] Regarding the communication between TX and RX, TX may selectively use any of a plurality of communication standards to communicate with RX. A communication form of a plurality of types of communication to be described below may be selectively used.

[0073] · In the first communication unit 104 of TX and the first communication unit 204 of RX ( Figure 3 ) based on the first standard (WPC standard).

[0074] · In the second communication unit 109 of TX and the second communication unit 212 of RX ( Figure 3 ) based on a second standard (a standard other than the WPC standard).

[0075] The UI unit 110 is connected to the control unit 101 and performs various types of outputs to the user. The various types of outputs include operations such as screen display, flashing and color change of light emitting diodes (LEDs), audio output from speakers, and vibration of the TX body. The UI unit 110 is implemented by a liquid crystal panel, a speaker, a vibration motor, and the like.

[0076] Next, we will refer to Figure 3 An example of the configuration of the power receiving device 200 is described. Figure 3RX includes a control unit 201 , a UI unit 202 , a power receiving unit 203 , a first communication unit 204 , a power receiving antenna 205 , a charging unit 206 , a battery 207 , and a memory 208 .

[0077] The RX further includes a first switch unit 209, a second switch unit 210, a resonant capacitor 211, a second communication unit 212, and a third switch unit 213. Figure 3 The functional block elements are examples of separate elements, but a plurality of functional block elements may be implemented as one hardware module.

[0078] The control unit 201 controls the various functional block elements of the RX by executing a control program stored in the memory 208. In addition, the control unit 201 may perform control for executing applications other than wireless power transmission. The control unit 201 is configured to include one or more processors such as a CPU and an MPU.

[0079] Furthermore, the entire RX (eg, the entire smartphone) may be controlled in cooperation with an operating system (OS) executed by the control unit 201. Alternatively, the control unit 201 is configured to include hardware such as an ASIC or an array circuit such as an FPGA compiled to perform predetermined processing.

[0080] The control unit 201 stores information to be stored in the memory 208 during execution of various types of processing, and can perform time measurement processing using a timer (not shown).

[0081] The UI unit 202 is connected to the control unit 201 and performs various types of outputs to the user. The various types of outputs include operations such as screen display, flashing and color change of light emitting diodes (LEDs), audio output from speakers, and vibration of the RX body. The UI unit 202 is implemented by a liquid crystal panel, a speaker, a vibration motor, and the like.

[0082] The power receiving unit 203 receives AC power (AC voltage and AC current) generated by electromagnetic induction of electromagnetic waves emitted from the TX power transmitting antenna 105 via the power receiving antenna (power receiving coil) 205. In addition, the power receiving unit 203 converts the AC power into DC power or AC power with a predetermined frequency and supplies the power to the charging unit 206.

[0083] The charging unit 206 charges the battery 207. The power receiving unit 203 includes a rectifying unit (rectifier or rectifying circuit) and a voltage control unit required to supply power to the load in RX. The rectifying unit converts the AC voltage and AC current received from the power transmitting antenna via the power receiving antenna 205 into DC voltage and DC current.

[0084] The DC voltage is referred to as the output voltage specific to the rectifying unit hereinafter. In addition, the DC current is referred to as the output current specific to the rectifying unit hereinafter. The voltage control unit converts the level of the DC voltage (the output voltage specific to the rectifying unit) output by the rectifying unit into a predetermined level.

[0085] The predetermined level is a level of DC voltage at which the control unit 201 and the charging unit 206 etc. can operate. The power receiving unit 203 supplies power for charging from the charging unit 206 to the battery 207. Assume that the power receiving unit 203 has a power supply capability sufficient to output 15 watts of power to the charging unit 206.

[0086] The first communication unit 204 communicates with the first communication unit 104 provided in the TX for power reception control based on the WPC standard. The first communication unit 204 is connected to the power receiving antenna 205 and the control unit 201. The first communication unit 204 acquires information transmitted from the TX by demodulating the electromagnetic wave input from the power receiving antenna 205.

[0087] The first communication unit 204 load-modulates or amplitude-modulates the input electromagnetic wave, and communicates with the TX by superimposing a signal related to information to be transmitted to the TX on the electromagnetic wave.

[0088] In addition to the control program, the memory 208 also stores information related to the status of TX and RX. The information related to the status of RX is acquired by the control unit 201. In addition, the information related to the status of TX can be acquired by the control unit 101 of TX and received by the first communication unit 204 or the second communication unit 212 to be described below.

[0089] The second communication unit 212 is connected to the control unit 201 and communicates with the TX according to a standard different from the WPC standard. For example, the second communication unit 212 communicates with the TX using an antenna different from the power receiving antenna 205. Figure 2 The second communication unit 109) communicates.

[0090] Examples include wireless local area network (LAN), Bluetooth (registered trademark) low energy (BLE), and near field communication (NFC). The frequency band used when receiving power in the power receiving antenna 205 is different from the frequency band used in communication of the second communication unit 212 .

[0091] Regarding the communication between TX and RX, RX may selectively use any of a plurality of communication standards to communicate with TX. A communication form of a plurality of types of communication to be described below may be selectively used.

[0092] Communication based on the first standard (WPC standard) is performed between the first communication unit 104 of TX and the first communication unit 204 of RX.

[0093] Communication based on the second standard (a standard other than the WPC standard) performed between the second communication unit 109 of TX and the second communication unit 212 of RX.

[0094] The first switch unit 209 is provided between the charging unit 206 and the battery 207, and is controlled by the control unit 201. The first switch unit 209 has a function of controlling whether to supply the power received by the power receiving unit 203 to the battery 207 and a function of controlling the size of the load.

[0095] When the first switch unit 209 is turned off and open by the control unit 201, the power received by the power receiving unit 203 is not supplied to the battery 207. When the first switch unit 209 is turned on and short-circuited by the control unit 201, the power received by the power receiving unit 203 is supplied to the battery 207.

[0096] Despite Figure 3 In the example of FIG. 2 , the first switch unit 209 is disposed between the charging unit 206 and the battery 207 , but the first switch unit 209 may also be disposed between the power receiving unit 203 and the charging unit 206 .

[0097] Alternatively, the first switch unit 209 may be disposed between the closed circuit formed by the power receiving antenna 205, the resonant capacitor 211, and the second switch unit 210 and the power receiving unit 203. In this case, the first switch unit 209 has a function of controlling whether the power received by the power receiving antenna 205 is supplied to the power receiving unit 203.

[0098] Although the first switch unit 209 Figure 3 Although described as one functional block element in the example of FIG. 2 , the first switching unit 209 may be implemented as a part of the charging unit 206 or the power receiving unit 203 .

[0099] Furthermore, the first switch unit 209 is not limited to the configuration of being inserted in series between the charging unit 206 and the battery 207 , and the first switch unit 209 may be inserted in parallel between the charging unit 206 and the battery 207 .

[0100] In this case, when the first switch unit 209 is turned off and open by the control unit 201, the power received by the power receiving unit 203 is supplied to the battery 207. When the first switch unit 209 is turned on and short-circuited by the control unit 201, the power received by the power receiving unit 203 is not supplied to the battery 207.

[0101] On the input side of the power receiving unit 203 , the second switch unit 210 is connected in parallel to the resonance capacitor 211 . The resonance capacitor 211 is connected to the power receiving antenna 205 via the third switch unit 213 .

[0102] The second switch unit 210 and the third switch unit 213 are controlled by the control unit 201. The third switch unit 213 has a function of controlling whether to open the terminal of the power receiving antenna 205.

[0103] When the third switch unit 213 is turned off by the control unit 201 , the terminal of the power receiving antenna 205 is in an open state. When the third switch unit 213 is turned on by the control unit 201 , the power receiving antenna 205 is connected to the power receiving unit 203 via the resonance capacitor 211 .

[0104] When the third switch unit 213 is turned on by the control unit 201 and the second switch unit 210 is turned on and short-circuited, the power receiving antenna 205 and the resonance capacitor 211 form a series resonance circuit and resonate at a specific frequency fB.

[0105] Current flows through the closed circuit formed by the power receiving antenna 205, the resonant capacitor 211, and the second switch unit 210, and no current flows through the power receiving unit 203. In addition, when the second switch unit 210 is turned off and the relevant circuit is open, the power received by the power receiving antenna 205 and the resonant capacitor 211 is supplied to the power receiving unit 203.

[0106] Not limited to Figure 3 In the example of, the second switch unit 210 can be arranged between the power receiving antenna 205 and the resonance capacitor 211. When the third switch unit 213 is in the ON state and the second switch unit 210 is in the ON state, the terminal of the power receiving antenna 205 is short-circuited. In addition, the third switch unit 213 can be arranged between the resonance capacitor 211 and the power receiving unit 203.

[0107] In this system, TX and RX perform wireless power transmission based on the WPC standard between the power transmitting antenna 105 and the power receiving antenna 205. In the WPC standard, the amount of power guaranteed when the power receiving device 200 receives power from the power transmitting device 100 is specified by a value called guaranteed load power (hereinafter referred to as "GP").

[0108] For example, GP indicates a power value at which the output of the load of the power receiving device 200 is guaranteed even if the coupling between the power receiving antenna 205 and the power transmitting antenna 105 weakens due to fluctuations in the positional relationship between the power receiving device 200 and the power transmitting device 100 and the power transmission efficiency decreases.

[0109] The load of the power receiving device 200 is Figure 3 The charging unit 206 and the battery 207 in the power receiving unit 203 and the like are provided, and the value of GP corresponds to the amount of power guaranteed to be output from the power receiving unit 203. Alternatively, the value of GP corresponds to the amount of power guaranteed to be output from the rectifying unit provided in the power receiving unit 203.

[0110] For example, assuming that the value of GP is 5 (Watts) and the positional relationship between the power receiving antenna 205 and the power transmitting antenna 105 is changed, even if the power transmission efficiency is reduced, the power transmitting device 100 performs power transmission control so that 5 W can be output to the load of the power receiving device 200.

[0111] Furthermore, GP is determined by negotiation between the power transmitting apparatus 100 and the power receiving apparatus 200. In addition, the present disclosure is not limited to GP, and the present embodiment can be applied to a configuration in which power is transmitted and received using power determined by mutual negotiation between the power transmitting apparatus and the power receiving apparatus.

[0112] When power is transmitted from the power transmission device 100 to the power receiving device 200, an object is assumed to be located near the power transmission device 100. The object in this case is an object that may affect power transmission from the power transmission device 100 to the power receiving device 200 and is an object different from the power receiving device 200 (foreign object).

[0113] The electromagnetic waves used for power transmission may affect foreign objects, and may increase the temperature of foreign objects and destroy foreign objects. The foreign objects in the present disclosure are, for example, clips or IC cards. Among the objects that are an integral part of the power receiving device and the product incorporating the power receiving device or the power transmitting device and the product incorporating the power transmitting device, an object that may unintentionally generate heat when exposed to the wireless power transmitted by the power transmitting antenna does not correspond to a foreign object.

[0114] The WPC standard specifies a method for suppressing a temperature rise or damage of a foreign object by stopping power transmission when the foreign object exists. Specifically, the power transmission device 100 can detect the presence of a foreign object on the charging base 300 .

[0115] The power loss method is a method of detecting foreign matter based on the difference between the transmitted power in the power transmission device 100 and the received power in the power reception device 200. The Q value measurement method is a method of detecting foreign matter based on the change in the quality factor (Q value) of the power transmission antenna 105 (power transmission coil) in the power transmission device 100.

[0116] However, foreign objects detected by the power transmission device 100 are not limited to objects located on the charging base 300. The power transmission device 100 may detect foreign objects located near the power transmission device 100. For example, the power transmission device 100 may detect foreign objects located within the power transmission range.

[0117] Will refer to Figure 4 Describes foreign object detection based on the power loss method specified in the WPC standard. Figure 4 , the horizontal axis represents the transmitted power of the power transmitting device 100 , and the vertical axis represents the received power of the power receiving device 200 .

[0118] On the graph line indicated by the straight line segment 1002, point 1000 corresponds to the first transmission power value Pt1 and the first reception power value Pr1, and point 1001 corresponds to the second transmission power value Pt2 and the second reception power value Pr2. On the graph line, point 1003 corresponds to the third transmission power value Pt3 and the third reception power value Pr3. The foreign matter to be detected is a conductive metal sheet or the like.

[0119] First, the power transmission device 100 transmits power to the power receiving device 200 at the first transmission power value Pt1, and the power receiving device 200 receives power at the first reception power value Pr1. This state is hereinafter referred to as a light load state. In addition, the power transmission device 100 stores the first transmission power value Pt1.

[0120] At this time, the power receiving device 200 performs load control so that the power to be received is the minimum power. Alternatively, the power receiving device 200 performs load control so that the power to be received is power within a prescribed predetermined range or power less than or equal to a predetermined threshold.

[0121] Here, in “power within a prescribed predetermined range” or “power less than or equal to a predetermined threshold value”, “power” is a power value of about 10% of a reference power to be described below.

[0122] In addition, the power receiving device 200 may disconnect the load from the power receiving antenna 205 so that the received power is not supplied to the load ( Figure 3 Alternatively, the power receiving device 200 may control the load so that predetermined power is supplied to the load.

[0123] This can be achieved by controlling the first switch unit 209. Then, the power receiving device 200 notifies the power transmitting device 100 of the first received power value Pr1. The power transmitting device 100, which receives the signal related to the first received power value Pr1 from the power receiving device 200, calculates the power loss between the power transmitting device 100 and the power receiving device 200.

[0124] The power loss at this time is Pt1 - Pr1 (= Ploss1 ). A calibration point (hereinafter abbreviated as CP) 1000 for indicating the correspondence relationship between Pt1 and Pr1 may be generated.

[0125] Subsequently, the power transmitting device 100 changes the transmission power value to the second transmission power value Pt2 and transmits power to the power receiving device 200, and the power receiving device 200 receives power having the second reception power value Pr2. Hereinafter, this state is referred to as a connected load state.

[0126] In addition, the power transmission device 100 stores the second transmission power value Pt2. At this time, the power receiving device 200 performs load control so that the power to be received is the maximum power. Here, the "maximum power" is power of a value close to the reference power to be described below.

[0127] Alternatively, the power receiving device 200 performs load control so that the power to be received is power within a prescribed predetermined range or power greater than or equal to a predetermined threshold. For example, the power receiving device 200 connects the power receiving antenna 205 to the load so that the received power is supplied to the load.

[0128] This can be achieved by controlling the first switch unit 209. Subsequently, the power receiving device 200 notifies the power transmitting device 100 of the second power receiving power value Pr2. The power transmitting device 100, which has received the signal related to the second power receiving power value Pr2 from the power receiving device 200, calculates the power loss between the power transmitting device 100 and the power receiving device 200. The power loss at this time is Pt2-Pr2 (=Ploss2). CP 1001 for indicating the correspondence relationship between Pt2 and Pr2 can be generated.

[0129] The power transmitting device 100 performs linear interpolation processing between CP 1000 and CP 1001 to generate a line segment 1002. The line segment 1002 indicates the relationship between the transmitted power and the received power in a state where no foreign matter is detected near the power transmitting device 100 and the power receiving device 200 (hereinafter referred to as a first detection state).

[0130] Based on the line segment 1002, when power transmission is performed at a predetermined power transmission power in the first detection state, the power transmission device 100 can estimate the power value received by the power reception device 200. For example, it is assumed that the power transmission device 100 transmits power at a third power transmission power value Pt3.

[0131] In this case, the power transmitting device 100 can estimate the third received power value Pr3 received by the power receiving device 200 based on the point 1003 on the line segment 1002 corresponding to Pt3.

[0132] As described above, based on a plurality of combinations of the transmission power value of the power transmitting device 100 and the reception power value of the power receiving device 200 measured when the load changes, the power loss between the power transmitting device 100 and the power receiving device 200 corresponding to the load can be obtained. In addition, the power loss between the power transmitting device 100 and the power receiving device 200 corresponding to all loads can be estimated based on the interpolation processing from a plurality of combinations of the transmission power value and the reception power value.

[0133] Therefore, the calibration process performed by the power transmitting device 100 and the power receiving device 200 so that the power transmitting device 100 obtains a combination of the transmitted power value and the received power value is called “power loss method calibration process”. Also, the calibration process is abbreviated as CAL process.

[0134] Consider a case where, after the CAL process of the power loss method, the power transmitting device 100 actually transmits power having the third transmission power value Pt3 to the power receiving device 200 , and the power transmitting device 100 receives a signal related to the reception power value Pr3 * from the power receiving device 200 .

[0135] The signal related to the received power value Pr3* is a received power data packet (mode 0) specified in the WPC standard, but other messages may be used.

[0136] Hereinafter, the received power data packet (mode 0) is referred to as RP0. RP0 includes, for example, the value of the received power value Pr3*. The power transmitting device 100 calculates Pr3-Pr3* (=Ploss_FO) by subtracting the received power value Pr3* actually received from the power receiving device 200 from the received power value Pr3 in the first detection state.

[0137] When foreign objects are located near the power transmitting device 100 and the power receiving device 200, Ploss_FO may be estimated as power consumed by the foreign objects (ie, power loss).

[0138] In the second detection state, the power transmission device 100 compares the power loss Ploss_FO consumed by the foreign object with a predetermined threshold value. When the value of the power loss Ploss_FO exceeds the threshold value, the power transmission device 100 can determine that there is a foreign object.

[0139] Alternatively, the power transmitting device 100 acquires the third received power value Pr3 in the first detection state from the power receiving device 200 , and obtains the power loss Pt3 - Pr3 (= Ploss3 ) between the power transmitting device 100 and the power receiving device 200 in advance.

[0140] Next, the power transmission device 100 obtains the received power value Pr3* from the power receiving device 200 in the second detection state, and calculates the power loss Pt3-Pr3* (=Ploss3*) between the power transmission device 100 and the power receiving device 200 in the second detection state. In addition, the power transmission device 100 can estimate the power loss Ploss_FO using Ploss3*-Ploss3.

[0141] As described above, there are two methods for calculating Ploss_FO in the second detection state.

[0142] · The first method calculates Ploss_FO from Pr3-Pr3*.

[0143] · Second method to calculate Ploss_FO from Ploss3*-Ploss3.

[0144] Although the second method is basically described in this embodiment, the contents of this embodiment can also be applied to the first method.

[0145] Next, we will refer to Figure 5 (A) and (B) describe foreign matter detection based on the Q value measurement method specified in the WPC standard. Figure 5 (A) is an explanatory schematic circuit diagram of a method of measuring a quality factor (Q factor or Q value) based on a Q value measurement method.

[0146] The AC power source 901 is a power source for outputting AC power generated by the TX power transmission unit 103. The power transmission antenna 902 corresponds to the power transmission antenna 105, and the capacitor 903 corresponds to the resonance capacitor 107. The power transmission antenna 902 and the capacitor 903 are connected in series.

[0147] The voltage value V8 is a voltage value of a predetermined frequency for operating the wireless power transmission system generated by the power transmission unit 103. The voltage value V9 is a voltage value applied to the power transmission antenna 902. Here, it is assumed that the TX can change the frequency associated with the voltage value.

[0148] In addition, the voltage values ​​V8 and V9 are voltage values ​​measured by TX when TX transmits an analog Ping or a digital Ping to RX. Since the voltage values ​​V8 and V9 are AC voltage values, their effective values ​​(RMS) can be used.

[0149] Figure 5 (B) shows a characteristic having a peak at 100kHz as an example of the measurement result of V9 / V8 for frequency. The horizontal axis is the frequency axis, and the vertical axis represents the voltage ratio "V9 / V8". Since V9 / V8 represents the quality factor related to the power transmission antenna 902, this value changes when an object is placed near the power transmission antenna 902.

[0150] The change in the quality factor differs depending on the case where no object is placed on TX, the case where RX is placed on TX, the case where a foreign object (metal piece, etc.) is placed on TX, and the case where RX and a foreign object are placed on TX.

[0151] In the negotiation phase, TX receives a FOD status data packet signal from RX. The FOD status data packet includes a reference quality factor value and a reference resonant frequency value.

[0152] The reference quality factor value is a quality factor that can be measured by the terminal of the power transmitting antenna of the test TX when the RX is placed on the test TX and there is no foreign matter nearby.

[0153] In addition, the reference resonance frequency value is a resonance frequency that can be measured by the terminal of the power transmission antenna of the test TX when the RX is placed on the test TX and there is no foreign matter nearby.

[0154] In the Q value measurement method, a threshold is set based on a reference quality factor value, and foreign matter detection is performed by comparing the threshold with the quality factor obtained from the actually measured V9 / V8.

[0155] Alternatively, a threshold value is set with reference to a reference resonance frequency value, and foreign matter detection is performed by comparing the threshold value with the resonance frequency obtained by actually measuring V9 / V8.

[0156] The RX and TX of this embodiment perform communication for power transmission and reception control based on the WPC standard. In the WPC standard, multiple stages including a power transmission stage for performing power transmission and one or more stages before actual power transmission are specified.

[0157] In each phase, necessary communication for power transmission and reception control is performed. For example, based on the data set obtained in the calibration phase, foreign object detection by the power loss method is performed in the power transmission phase.

[0158] Furthermore, foreign object detection by the Q value measurement method is performed before power transmission (before digital Ping transmission and in the negotiation phase or the re-negotiation phase).

[0159] The stages before power transmission in the WPC standard are a selection stage, a ping stage, and an identification and configuration stage (configuration stage).

[0160] In addition, there is a negotiation phase and a calibration phase. In the following, the identification and configuration phase is referred to as the I&C phase. In the following, the processing of each phase will be described.

[0161] In the selection phase, TX intermittently transmits a simulated Ping to detect that an object is placed on the charging base of TX. For example, it is detected that RX or a conductor sheet is placed on the charging base. TX detects one or both of the voltage value and the current value of the power transmission antenna 105 when transmitting the simulated Ping.

[0162] When the voltage value is lower than the threshold or the current value exceeds the threshold, TX determines that an object exists and transitions to the Ping phase. Alternatively, when the quality factor obtained from the voltage value or the current value satisfies a predetermined condition, TX determines that an object exists and transitions to the Ping phase.

[0163] In the Ping phase, TX transmits a digital Ping with higher power than the analog Ping. The magnitude of the power of the digital Ping is high enough to activate the control unit of the RX placed on the TX.

[0164] RX notifies TX of the power receiving voltage value. Thus, when receiving a response from RX that has received the digital Ping, TX recognizes that the object detected in the selection phase is RX.

[0165] When TX receives the notification of the power receiving voltage value from RX, it transitions to the I&C phase. In addition, before transmitting the digital Ping, TX measures the quality factor related to the power transmitting antenna 105 using, for example, an analog Ping.

[0166] This measurement result is used when performing a foreign matter detection process using the Q value measurement method. In addition, depending on the version of the WPC standard, the above-mentioned selection phase may be included as a part of the above-mentioned Ping phase, and may be referred to as the Ping phase.

[0167] In the I&C phase, TX identifies RX and obtains device configuration information (capability information) from RX. RX transmits signals of an ID packet and a configuration packet. The ID packet includes identifier information related to RX, and the configuration packet includes device configuration information (capability information) of RX.

[0168] The TX that has received the signal of the ID packet and the configuration packet responds with an acknowledgement (positive response ACK). In addition, the I&C phase ends. In addition, the I&C phase may be referred to as a configuration phase according to the version of the WPC standard.

[0169] In the negotiation phase, the GP value is determined based on the GP value required by the RX and the power transmission capability of the TX, etc. In addition, the TX receives a FOD status packet including a reference quality factor value and a reference resonant frequency value from the RX.

[0170] In the Q value measurement method, the presence or absence of foreign matter is determined based on a threshold value based on a reference quality factor value and a reference resonance frequency value. TX performs foreign matter detection processing using the Q value measurement method in accordance with a request from RX.

[0171] In addition, in the WPC standard, once transitioned to the power transmission phase, a method for performing processing similar to that of the negotiation phase is performed again according to a request of the RX. The phase in which these processes are performed after transitioning from the power transmission phase is called a re-negotiation phase.

[0172] In the calibration phase, the CAL process of the power loss method is performed based on the WPC standard. In addition, the RX notifies the TX of the predetermined received power value and makes adjustments so that the TX transmits power efficiently.

[0173] The predetermined received power value is, for example, a received power value in a light load state or a maximum load state (connected load state). The received power value provided in the notification to TX is used for foreign object detection processing by the power loss method.

[0174] In the power transmission phase, TX and RX perform control processing for starting and continuing power transmission, error processing, and stopping power transmission due to full charging, etc. TX and RX perform communication processing for power transmission and power reception control.

[0175] For example, using the power transmitting antenna 105 and the power receiving antenna 205 used when wireless power transmission is performed based on the WPC standard, communication is performed by superimposing a signal on an electromagnetic wave transmitted from the power transmitting antenna 105 or the power receiving antenna 205 .

[0176] The range in which communication based on the WPC standard can be performed between TX and RX is similar to the range in which power transmission of TX can be performed. In addition, depending on the version of the WPC standard, the calibration phase may also be referred to as a power transmission phase as part of the power transmission phase.

[0177] Next, we will refer to Figure 6 Describe the functionality of the TX control unit. Figure 6 1 is a block diagram showing an example of a functional configuration of the control unit 101 of the power transmission device 100 (TX). The control unit 101 includes a communication control unit 301 , a power transmission control unit 302 , a measurement unit 303 , a setting unit 304 , and a state detection unit 305 .

[0178] The communication control unit 301 controls the communication with the RX based on the WPC standard via the first communication unit 104 or controls the communication with the RX via the second communication unit 109. The power transmission control unit 302 controls the power transmission to the RX by controlling the power transmission unit 103.

[0179] The measuring unit 303 measures a waveform attenuation index to be described below. The measuring unit 303 also measures the power transmitted to the RX via the power transmission unit 103 and measures the average power transmission per unit time. The measuring unit 303 also measures the quality factor associated with the power transmission antenna 105 .

[0180] Furthermore, the measuring unit 303 measures the temperature using temperature sensors arranged at a plurality of locations of the power transmitting device 100. Furthermore, the measuring unit 303 measures a quantity indicating the electromagnetic coupling state between the power transmitting antenna 105 and the power receiving antenna 205 (eg, coupling coefficient).

[0181] In the above method, the setting unit 304 calculates and sets the threshold for detecting foreign matter in the Q value measurement method and the threshold for detecting foreign matter in the power loss method. In addition, in the method to be described below, the setting unit 304 sets the threshold for foreign matter detection in the waveform attenuation method.

[0182] In addition, the setting unit 304 calculates and sets a threshold value for detecting a foreign object or a threshold value for detecting a positional shift between TX and RX, for example, based on the coupling coefficient between the power transmitting antenna 105 and the power receiving antenna 205 measured by the measuring unit 303. In addition, the setting unit 304 calculates and sets a threshold value for detecting a foreign object or a threshold value for detecting a positional shift between TX and RX, for example, based on the temperature of the power transmitting device measured by the measuring unit 303.

[0183] The state detection unit 305 detects the state of TX and RX. For example, the state detection unit 305 detects a foreign object between TX and RX, and detects a positional deviation between the power transmitting antenna 105 and the power receiving antenna 205.

[0184] More specifically, state detection processing based on a power loss method, a Q value measurement method, a waveform attenuation method, the temperature measured in the power transmitting device 100 , and the electromagnetic coupling state (e.g., coupling coefficient) between the power transmitting antenna 105 and the power receiving antenna 205 may be performed.

[0185] The state detection unit 305 may perform foreign object detection and positional displacement detection between the power transmitting antenna 105 and the power receiving antenna 205 in other methods. For example, in a TX having an NFC communication function, the state detection unit 305 performs state detection processing using a partner detection function corresponding to the NFC standard.

[0186] In addition to detecting the presence of foreign matter and the electromagnetic coupling state between the power transmitting antenna and the power receiving antenna, the state detection unit 305 can also detect a state change on TX. For example, the state detection unit 305 can detect an increase or decrease in the number of power receiving devices 200 on TX.

[0187] The setting unit 304 sets a threshold value used as a reference for determining the presence or absence of foreign matter after the TX performs state detection. The state detection is, for example: state detection based on a power loss method, a Q value measurement method, or a waveform attenuation method; state detection based on a temperature measured in the power transmission device 100; or state detection based on a coupling coefficient between the power transmission antenna 105 and the power receiving antenna 205.

[0188] In addition, the setting unit 304 may use other methods to set the judgment threshold required for the state detection process. The state detection unit 305 may perform foreign object detection processing and processing for detecting the positional offset between the power transmitting antenna 105 and the power receiving antenna 205 based on the threshold set by the setting unit 304 and the measurement result of the measurement unit 303.

[0189] For example, the state detection unit 305 may acquire data such as a waveform attenuation index, transmitted power, quality factor, temperature measured in the power transmission device 100 , and a coupling coefficient between the power transmitting antenna 105 and the power receiving antenna 205 as the measurement result of the measurement unit 303 .

[0190] Depend on Figure 6 The processes performed by the illustrated communication control unit 301 , power transmission control unit 302 , measurement unit 303 , setting unit 304 , and state detection unit 305 can be realized using a program executed by a CPU or the like provided in the control unit 101 .

[0191] According to the independent program, the processes are executed in parallel while synchronization between the programs is achieved by event processing, etc. However, two or more of these processes may be merged into the process of one program.

[0192] Subsequently, an example of the flow of processing related to power transmission and power reception control performed by TX and RX will be described. Figure 7 1 is a flowchart showing an example of a power transmission control process executed by the TX. For example, this process is realized by the TX control unit 101 executing a program read from the memory 106.

[0193] In addition, the process may be executed according to the case where the power of TX is turned on, the case where the user of TX inputs an instruction to start the wireless power transmission application, or the case where TX is connected to a commercial power source and receives the supplied power. In addition, the process may be started by other triggers.

[0194] exist Figure 7 In S1201, TX performs processing designated as the selection phase and the Ping phase in the WPC standard and waits for RX to be placed. TX repeatedly and intermittently transmits the simulated Ping of the WPC standard to detect an object located within the power transmission range.

[0195] For example, TX can detect that RX or a conductor sheet is placed on the charging base 300. When an object is detected within its power transmission range, TX transmits a digital Ping. The power of the digital Ping is greater than that of the analog Ping and is sufficient to activate the control unit 201 of the RX placed on the TX.

[0196] When there is a predetermined response to the digital Ping, TX determines that the detected object is RX and RX is placed on the charging base 300. Here, the "predetermined response" is a signal strength (SIG) packet transmitted by RX.

[0197] The packet includes a signal strength value indicating the signal strength of the signal received by RX. The signal strength value is calculated based on the voltage output by the rectifying unit (rectifier) ​​of the power receiving unit 203 measured by RX (output voltage specific to the rectifying unit) or the voltage (open circuit voltage) of the open circuit including the power receiving antenna 205 measured by RX.

[0198] Alternatively, the signal strength value is calculated from the received power value measured by the RX, etc. In addition, the TX measures the quality factor of the power transmitting antenna 105 before transmitting the digital Ping. This measurement result is used when performing the foreign object detection process using the Q value measurement method.

[0199] After detecting the placement of RX, in S1202, TX acquires identification information from RX according to the communication in the I&C phase specified in the WPC standard. In the I&C phase, RX transmits an identification packet (ID packet) to TX.

[0200] In addition to the manufacturer code and the basic device ID which are identification information of each individual of the RX, an information element for identifying the version of the supported WPC standard is also stored in the ID packet.

[0201] In addition, RX transmits a configuration packet to TX. The configuration packet includes the following RX capability information.

[0202] Information used to identify the version of the WPC standard supported by RX.

[0203] A maximum power value or reference power, which is a value for identifying the maximum power that the RX can supply to the load.

[0204] Information used to indicate whether the RX has the negotiation function of the WPC standard.

[0205] Parameters used in frequency shift modulation, which is a communication modulation scheme used when TX transmits information to RX.

[0206] When receiving the above packet from RX, TX transmits an affirmative response ACK to RX, and the I&C phase ends. In addition, TX may acquire RX identification information by a method other than communication in the I&C phase of the WPC standard.

[0207] In addition, the identification information of each individual of RX may be a wireless power ID. Alternatively, the identification information may be any other identification information for identifying an individual of RX such as a Bluetooth address (hereinafter referred to as "BD_ADDR") unique to the second communication unit 212 of RX.

[0208] In addition, BD_ADDR is an 8-byte address used in BLE. BD_ADDR is, for example, a public address specified in the BLE standard indicating individual identification information about the manufacturer of RX and the BLE communication function (second communication unit 212). BD_ADDR may be a random address.

[0209] Then, in S1203, TX determines GP by negotiation with RX based on the request from RX and the power transmission capability of its own device. In S1203, communication in the negotiation phase of the WPC standard is performed.

[0210] First, RX provides notification of the requested GP value by transmitting a specific request to TX. TX determines whether to accept the request based on its own device's power transmission capabilities or other conditions.

[0211] When the request is accepted, TX transmits an affirmative response ACK to RX. When the request is not accepted, TX transmits a negative response NACK or NAK to RX. When TX accepts the request from RX, the determined GP value is the value requested by RX.

[0212] When TX does not accept the request from RX, the value is a predetermined value determined by the WPC standard (e.g., 5 watts). Alternatively, when TX obtains information indicating that RX does not correspond to the negotiation phase (e.g., S1302 to be described below), TX does not perform communication in the negotiation phase and decides the GP value to be a predetermined value. The predetermined value is, for example, a value pre-specified in the WPC standard (e.g., 5 watts).

[0213] In addition, TX performs foreign object detection processing using the Q value measurement method according to a request from RX. TX receives a FOD status data packet from RX. The packet includes the above-mentioned reference quality factor value and reference resonance frequency value.

[0214] In addition, TX performs foreign matter detection based on the Q value measurement method. This foreign matter detection is performed based on the following information.

[0215] TX The quality factor and resonance frequency of the power transmission antenna 105 measured before transmitting the digital Ping.

[0216] • A threshold value based on a reference quality factor value and a reference resonant frequency value received by the TX from the RX.

[0217] Then, in S1204, TX and RX perform a process in the calibration phase of the WPC standard (CAL process). In the calibration phase, TX performs a CAL process of the power loss method based on the determined reference power value or GP value.

[0218] First, RX transmits a signal having information about the received power in a light load state (hereinafter referred to as first reference received power information) to TX. The light load state is, for example, a disconnected load state, a load state in which the received power value of RX is less than or equal to a first threshold, or a load state in which the received power value of RX is within a prescribed predetermined range (hereinafter referred to as "first range").

[0219] In the present embodiment, the first reference power reception electric power information is assumed to be 500 milliwatts. The first reference power reception electric power information is information included in a reception power data packet (mode 1) specified in the WPC standard, but other messages may be used.

[0220] Hereinafter, the reception power data packet (pattern 1) is denoted by RP1. TX determines whether to accept the first reference reception power information based on the control error value included in the control error (CE) data packet received from RX.

[0221] When the first reference received power information has been received, TX transmits an acknowledgement ACK to RX. Also, when the first reference received power information has not been received, TX transmits a negation NAK to RX.

[0222] Next, RX performs processing for transmitting to TX a signal having information about the received power in the connected load state (hereinafter referred to as the second reference received power information). The connected load state is, for example, a maximum load state, a load state in which the transmitted power value is greater than or equal to the second threshold, or a load state in which the power received by RX is the maximum power.

[0223] Here, the "maximum power" is power having a value close to the reference power. Alternatively, the connected load state is a load state in which the received power value of the RX is within a prescribed predetermined range (hereinafter referred to as the "second range"). Here, the second range is a range in which the power value is greater than the first range.

[0224] In the present embodiment, the second reference received power information is assumed to be 15 W. The second reference received power information is information included in a received power data packet (mode 2) specified in the WPC standard, but other messages may be used.

[0225] Hereinafter, the reception power data packet (mode 2) is denoted by RP2. TX determines whether to receive the second reference reception power information based on the control error value included in the control error (CE) data packet received from RX.

[0226] When the second reference power receiving information has been received, TX transmits an affirmative response ACK to RX. Also, when the second reference power receiving information has not been received, TX transmits a negative response NAK to RX. TX transmits an affirmative response ACK to the second reference power receiving information from RX and completes the CAL process.

[0227] According to the above CAL processing, TX can calculate the power loss amount between TX and RX in the light load state and the connected load state based on the transmission power value of TX and the received power values ​​included in the first reference received power information and the second reference received power information.

[0228] In addition, when interpolation processing is performed between two or more power loss amounts, TX can calculate the power loss amount between TX and RX among all the transmission powers that TX can obtain. For example, all the transmission powers that TX can obtain are any power in the range of 500 mW to 15 W received by RX in this embodiment.

[0229] Subsequently, in S1205, TX transmits power until the battery 207 of RX is fully charged. In S1205, communication in the power transmission phase of the WPC standard is performed.

[0230] The RX repeatedly transmits a control error (CE) data packet (hereinafter referred to as a "CE packet") to the TX at a time interval of t_interval. The t_interval is a value defined in the WPC standard, for example, 250 milliseconds.

[0231] The CE packet includes a request for the degree of increase or decrease of the transmission power. The TX adjusts the transmission power by controlling the current or voltage of the power transmission antenna 105 based on the received CE packet.

[0232] That is, the CE packet includes data of parameters for adjusting the power to be transmitted. By repeating this process, power transmission with appropriate power corresponding to the request of RX is basically performed in real time.

[0233] When the battery 207 is fully charged, the RX transmits an end power transfer data packet (hereinafter referred to as an "EPT packet") to end the power transfer phase. The RX may transmit an EPT packet for reasons other than full charging.

[0234] In addition, when the power transfer phase ends, TX stops transmitting power for charging RX. In addition, if the next CE packet cannot be received when the time t_timeout has passed since the last CE packet was received, TX determines that RX has been removed from the charging base 300.

[0235] In this case, the power transfer phase ends. t_timeout is a value defined in the WPC standard, for example, 1500 milliseconds.

[0236] During the power transfer phase, RX may transmit packets other than CE packets to TX. For example, there is a charge status data packet for informing TX of the status of the battery 207 of RX.

[0237] In this packet, a charge status value indicating the percentage to which the battery 207 has been charged is stored. When TX receives the charge status data packet, TX notifies the user of the charge status by displaying the charge status in characters or figures based on the charge status value using the UI unit 110, for example.

[0238] Regarding the charging status data packet, TX can receive the charging status data packet at any time, or provide notification to the user at any timing. In the power transmission phase, TX transmits power to RX and performs foreign object detection processing based on the power loss method.

[0239] For example, according to the CAL process, the power loss amount between TX and RX in the first detection state during the power transmission process is calculated based on the difference between the transmission power value and the reception power value. The calculated power loss amount corresponds to the reference power loss amount when there is no foreign matter.

[0240] Furthermore, when it is determined that the difference between the reference power loss amount and the power loss amount between TX and RX measured during power transmission after the CAL process is greater than or equal to the threshold, TX determines that the state is the second detection state.

[0241] Will refer to Figure 8 An example of the flow of a process related to power reception control executed by the RX is described. This process is realized by, for example, the control unit 201 of the RX executing a program read from the memory 208 .

[0242] In S1301, RX performs the processing specified in the selection phase and the Ping phase of the WPC standard, and waits for its own device to be placed on TX. RX detects the placement on TX by detecting a digital Ping from TX, for example.

[0243] When RX detects that its own device has been placed on TX, in S1302 , it transmits a signal including identification information about the device to TX through an ID packet and a configuration data packet.

[0244] In addition, the RX identification information may be transmitted by a method other than the communication in the I&C phase of the WPC standard. In addition, other identification information such as BD_ADDR may be used as long as the information can be used to identify each individual of the RX. In addition, in S1302, the RX may transmit information other than the identification information to the TX.

[0245] Then, in S1303, RX transmits a signal including information on the requested GP value to TX, and waits for a response from TX to decide the GP. In S1303, communication in the negotiation phase of the WPC standard is performed.

[0246] RX transmits a FOD status data packet to TX, which includes a reference quality factor value and a reference resonant frequency value.

[0247] Then, in S1304, RX and TX perform processing in the calibration phase of the WPC standard (CAL processing). The processing performed by RX in this phase is as described above.

[0248] Subsequently, in S1305, RX receives power until the battery 207 is fully charged. The processing performed by RX in this phase is as described above. In the power transmission phase, RX and TX perform foreign matter detection processing based on the power loss method.

[0249] In S1305 , RX repeatedly transmits CE packets at intervals of t_interval, and finally transmits an EPT packet to TX to end the process.

[0250] As described above, the power loss method is a method of detecting foreign matter based on the result of measuring the amount of power loss during power transmission from TX to RX. This method has the disadvantage that the accuracy of foreign matter detection decreases when TX is transmitting a large amount of power, but has the advantage that high power transmission efficiency can be maintained because foreign matter detection processing can be performed while power transmission continues.

[0251] On the other hand, only with foreign object detection based on the power loss method during the power transmission phase, there is a possibility that false detection of foreign objects may occur, or false detection that the absence of foreign objects is determined regardless of whether foreign objects exist may occur.

[0252] For example, suppose that during power transmission in the power transmission phase, there is a foreign object near TX and RX. In this case, since there is a possibility that heat generation from the foreign object or the like may increase, it is necessary to improve the accuracy of foreign object detection in the power transmission phase.

[0253] Therefore, a foreign object detection method using a waveform attenuation method will be described. In this method, TX can detect foreign objects based on the attenuation state of the power transmission waveform (voltage waveform or current waveform) related to power transmission to RX. That is, foreign object detection can be performed without using a newly designated foreign object detection signal, etc.

[0254] Fig. 9 This is an explanatory diagram of the principle of foreign object detection based on the waveform attenuation method. An example of foreign object detection using a power transmission waveform related to power transmission from the power transmitting device 100 (TX) to the power receiving device 200 (RX) will be described. Fig. 9 , the horizontal axis is the time axis, and the vertical axis represents the voltage value or the current value.

[0255] Fig. 9 The waveform 600 shown shows, for example, a change over time in the voltage value of the high frequency voltage applied to the power transmission antenna 105 of TX. TX, which transmits power to RX via the power transmission antenna 105, stops power transmission at time T0.

[0256] At time T0, power supply for power transmission from power supply unit 102 is stopped, and power supply for power transmission to power transmission antenna 105 is stopped. The frequency f1 of the power transmission waveform before stopping power transmission at time T0 is, for example, a fixed frequency between 87 kHz and 205 kHz used in the WPC standard.

[0257] Point 601 on waveform 600 is a point on the envelope of the high frequency voltage, and corresponds to voltage value A1 at time T1. At point 601, (T1, A1) indicates that the voltage value at time T1 is A1.

[0258] Point 602 on waveform 600 is a point on the envelope of the high frequency voltage, and corresponds to voltage value A2 at time T2. At point 602, (T2, A2) indicates that the voltage value at time T2 is A2.

[0259] The quality factor (Q factor or Q value) as the quality factor of the power transmission antenna 105 can be obtained based on the change in the voltage value over time after time T0. For example, TX calculates the quality factor by equation (1) based on the time and voltage values ​​at points 601 and 602 on the envelope of the high-frequency voltage and the frequency f2 of the high-frequency voltage after stopping power transmission at time T0.

[0260] Q=π·f2·(T2-T1) / ln(A1 / A2) Formula (1)

[0261] In equation (1), ln represents a natural logarithmic function. In addition, the frequency (f1) of the power transmission waveform when TX transmits power to RX may be different from the frequency (f2) of the power transmission waveform when TX stops transmitting power to RX.

[0262] When foreign matter exists near TX and RX, the value of the quality factor decreases because the foreign matter causes energy loss. Therefore, when focusing on the slope of the attenuation of the voltage value, the slope of the straight line connecting point 601 and point 602 is greater when foreign matter exists than when foreign matter does not exist.

[0263] When energy loss occurs due to foreign matter, the decay rate of the amplitude of waveform 600 increases. For example, in the waveform decay method, the presence or absence of foreign matter can be determined based on the decay state of the voltage value between points 601 and 602.

[0264] When actually judging the presence or absence of foreign matter, the judgment can be made by comparing some numerical values ​​used to indicate the attenuation state. For example, when the quality factor is used for judgment, the value of the quality factor is less than the reference value, indicating that the waveform attenuation rate (the degree of reduction in the amplitude of the waveform per unit time) is higher.

[0265] As another example, there is a method of making a judgment using the slope of a straight line connecting points 601 and 602 calculated by (A1-A2) / (T2-T1). In addition, when the time (T1 and T2) for measuring the decay state of the voltage value is fixed, the difference between the voltage values ​​(A1-A2) and the ratio of the voltage values ​​(A1 / A2) can be used to judge the presence or absence of foreign matter.

[0266] Alternatively, if the voltage value A1 immediately after the power supply is stopped is constant, the voltage value A2 after a predetermined time has passed can be used to determine the presence of foreign matter. Alternatively, the time (T2-T1) that has passed until the voltage value A1 becomes the predetermined voltage value A2 can be used to determine the presence of foreign matter.

[0267] In the waveform attenuation method, the presence of foreign matter can be determined by the attenuation state of the waveform during the period of power transmission stop. In this embodiment, indicators such as quality factors indicating the attenuation state are collectively referred to as "waveform attenuation indicators".

[0268] although Fig. 9 The vertical axis of has been described as the axis of the voltage value of the high frequency voltage applied to the TX power transmission antenna 105, but Fig. 9 The vertical axis of can be used as the value of the current flowing through the power transmitting antenna 105. As in the case of the voltage value, the attenuation state of the current value during the period in which the power transmission is stopped changes depending on the presence or absence of foreign matter.

[0269] When foreign matter is present, the waveform attenuation rate is higher than when foreign matter is not present. Therefore, a method similar to the above method can be applied to detect foreign matter regarding the change over time of the current value flowing through the power transmitting antenna 105.

[0270] That is, the quality factor calculated based on the current waveform, the slope of the attenuation of the current value, the difference between the current values, the ratio of the current values, the absolute value of the current value, and the time until the current value becomes a predetermined value are used as waveform attenuation indicators to determine the presence or absence of foreign matter, and foreign matter detection can be performed.

[0271] There is also a method based on both the attenuation state of the voltage value and the attenuation state of the current value. In this method, the presence or absence of foreign matter can be determined using an evaluation value calculated from the waveform attenuation index of the voltage value and the waveform attenuation index of the current value.

[0272] In addition, the present invention is not limited to the example of measuring the waveform attenuation index during the period when TX temporarily stops power transmission. The waveform attenuation index may be measured during the period when TX temporarily reduces the power supplied from the power supply unit 102 from a predetermined power level to a lower power level.

[0273] That is, the waveform attenuation index during the period when the power supply for power transmission to the power transmission antenna 105 is temporarily reduced from a predetermined power level to a lower power level can be measured. In addition, the power transmission unit 103 can limit or stop the above-mentioned power supply for power transmission to the power transmission antenna 105 based on the instruction signal of the control unit 101.

[0274] Although a configuration in which the voltage value or the current value at two time points during the period of TX limited power transmission is measured is adopted in the above-described example, the voltage value or the current value at three or more time points may be measured.

[0275] Will refer to Fig.10 A foreign object detection method based on a power receiving waveform according to a waveform attenuation method is described. Fig.10 The power transmission waveform shown is a power transmission waveform when a foreign object is detected by the waveform attenuation method, the horizontal axis represents time, and the vertical axis represents the voltage value or current value of the power transmission antenna 105.

[0276] During the transient response period immediately after TX starts power transmission, the power transmission waveform is unstable. Therefore, during this transient response period, control is performed so that RX does not perform communication (communication based on amplitude modulation or load modulation) with TX.

[0277] In addition, control is performed so that TX does not communicate with RX (communication based on frequency shift modulation). Hereinafter, this period is referred to as a communication disabled period. However, during the communication disabled period, TX transmits power to RX. In addition, when the communication disabled period has passed, TX transmits power to RX.

[0278] Hereinafter, this period is referred to as the power transmission period. When TX has received a foreign object detection execution request (packet or command) from RX, TX temporarily stops power transmission or temporarily reduces the power transmission after a predetermined period of time has passed. Hereinafter, this predetermined period of time is referred to as the preparation period.

[0279] The foreign object detection execution request (packet or command) may be RP0, RP1, or RP2. Since the power transmission unit 103 of the TX that has received the foreign object detection execution request temporarily stops power transmission or temporarily reduces the power transmission, the amplitude of the power transmission waveform is attenuated. The period from the time when power transmission is temporarily stopped or the time when the power transmission power is temporarily reduced to the time when power transmission is restarted or the time when the power transmission power begins to recover is called the power transmission power control period.

[0280] The TX calculates a waveform attenuation index based on the attenuated waveform, and compares the calculated waveform attenuation index with a predetermined threshold value to determine the presence or absence of foreign matter or the possibility (existence probability) of the presence of foreign matter (hereinafter also referred to as foreign matter determination). Foreign matter determination can be performed during the power transmission control period, the communication prohibition period, or the power transmission period.

[0281] After the transmission power control period has passed, when no foreign matter is detected, TX controls the restart of power transmission or the restoration of the transmission power. During the transient response period immediately after the control starts, because the power transmission waveform is unstable, this period becomes a communication prohibition period. Subsequently, this period turns into a power transmission period in which power is stably transmitted from TX to RX.

[0282] As described above, TX repeatedly controls the start of power transmission, the communication prohibition period, the power transmission period, the preparation period, and the power transmission power control period. TX calculates the waveform attenuation index based on the attenuation waveform at a predetermined timing, and judges foreign matter based on the comparison result of the calculated waveform attenuation index and the predetermined threshold. That is, foreign matter judgment can be performed based on the voltage value or current value at two or more time points during the predetermined period of time when the power transmission is restricted (including the stop of the power transmission).

[0283] On the other hand, during the transmission power control period, when elements such as the power receiving unit 203, the charging unit 206 and the battery 207 are connected to the power receiving antenna 205 and the resonance capacitor 211 of the power receiving device 200, the waveform attenuation index is affected by the load of these elements.

[0284] That is, the value of the waveform attenuation index changes with the states of the power receiving unit 203, the charging unit 206, and the battery 207. As a result, for example, even if the value of the waveform attenuation index is large, it is difficult to distinguish whether it is due to the influence of foreign matter or due to a change in the state of each of the power receiving unit 203, the charging unit 206, the battery 207, and the like.

[0285] Therefore, when foreign matter is detected by measuring the waveform attenuation index, the control unit 201 of RX turns off the first switch unit 209 during the preparation period. Thereby, the influence of the battery 207 can be suppressed.

[0286] In addition, a similar effect can be obtained by setting the state of the first switch unit 209 to a light load state instead of a disconnected state. In addition, a similar effect can be obtained even if the RX controls the load so that the power to be received becomes the minimum power instead of the first switch unit 209 disconnected state.

[0287] Alternatively, even if RX controls the load so that the power to be received becomes power within a prescribed predetermined range or power less than or equal to a predetermined threshold instead of the state in which the first switch unit 209 is disconnected, a similar effect can be obtained.

[0288] Here, in "power within a prescribed predetermined range" or "power less than or equal to a predetermined threshold", "power" is a power value of about 10% of the reference power. Alternatively, the RX may control the load so that the predetermined power is supplied to the load, instead of the first switch unit 209 being disconnected.

[0289] These can be realized by controlling the first switch unit 209. Alternatively, the control unit 201 turns on the second switch unit 210, the second switch unit 210 is short-circuited, and current flows through a closed loop formed by the power receiving antenna 205, the resonance capacitor 211, and the second switch unit 210.

[0290] Thereby, it is possible to suppress the influence of the power receiving unit 203, the charging unit 206, and the battery 207. The RX transmits a foreign matter detection execution request (command) to the TX, and the above-described processing is performed during the preparation period.

[0291] By acquiring a waveform attenuation index based on the power transmission waveform measured in a state where the first switch unit 209 is disconnected or the second switch unit 210 is turned on and short-circuited (connected), more accurate foreign object detection can be performed. Alternatively, when both the first switch unit 209 is disconnected and the second switch unit 210 is short-circuited (connected), more accurate foreign object detection can be performed.

[0292] Alternatively, during the preparation period, control may be performed such that the RX mode transitions to the low power consumption mode or power consumption is uniform in a state where the first switch unit 209 is turned on and short-circuited and the second switch unit 210 is turned off and disconnected.

[0293] When the power consumption in RX is uneven or a large amount of power is consumed, the value of the waveform attenuation index based on the attenuation waveform is affected by the fluctuation of the power consumption. In order to suppress the related influence, it is effective to limit or stop the operation of the software application operating in RX or set the mode of the hardware function block of RX to low power consumption mode or operation stop mode.

[0294] By detecting foreign objects using a waveform attenuation index based on a power transmission waveform measured in a state where power consumption of RX is suppressed, foreign objects can be detected with higher accuracy.

[0295] Likewise, even in TX, when measuring the waveform attenuation index, if elements such as the power transmission unit 103 , the first communication unit 104 , and the power supply unit 102 are connected to the power transmission antenna 105 and the resonance capacitor 107 of the power transmission device 100 , the waveform attenuation rate is also affected by these elements.

[0296] That is, the value of the waveform attenuation index changes with the state of each of the power transmission unit 103, the first communication unit 104, and the power supply unit 102. As a result, for example, even if the value of the waveform attenuation index is large, it is difficult to distinguish whether it is due to the influence of foreign matter or due to the influence of the power transmission unit 103, the first communication unit 104, and the power supply unit 102.

[0297] Therefore, when TX has received a foreign object detection execution request (command) from RX, the control unit 101 turns on the switch unit 108 during the preparation period, and current flows through a closed loop circuit formed by the power transmission antenna 105, the resonance capacitor 107, and the switch unit 108. Thus, when the waveform attenuation index is measured in TX, the influence of the power transmission unit 103, the first communication unit 104, and the power supply unit 102 can be suppressed.

[0298] Alternatively, a switch (not shown) is provided between the power transmitting antenna 105 and the power transmitting unit 103 and disconnected during the preparation period so that the influence of the power supply unit 102 , the power transmitting unit 103 , and the first communication unit 104 can be suppressed.

[0299] Alternatively, a switch may be provided between the power transmission unit 103 and the closed loop circuit formed by the power transmission antenna 105, the resonance capacitor 107, and the switch unit 108. When the TX measures the waveform attenuation index and detects foreign matter, the above influence can be suppressed by disconnecting the closed loop circuit and the power transmission unit according to the control of the switch.

[0300] As described above, at least one or more of the short-circuit (connected) state in which the switch unit 108 is turned on, the disconnected state of the switch related to the power transmission antenna 105 and the power transmission unit 103, and the disconnected state of the switch related to the closed loop circuit and the power transmission unit 103 are realized. As a result, foreign matter can be detected with higher accuracy.

[0301] Next, a method of setting a threshold value of a waveform attenuation index for state detection of TX and RX and foreign matter judgment based on the waveform attenuation method will be described. The measured value of the waveform attenuation index can be compared with a predetermined threshold value, and foreign matter can be judged based on the comparison result.

[0302] The first threshold setting method is a method in which TX maintains a predetermined value that is a common value that does not depend on RX serving as a power transmission target. The threshold is a fixed value or a variable value determined by TX according to the situation.

[0303] When foreign matter is present, the waveform attenuation rate of the power transmission waveform during the power transmission control period increases. Therefore, the value of the waveform attenuation index acquired in the absence of foreign matter is maintained and set as a threshold. By comparing the measured value of the waveform attenuation index with the threshold, it can be determined that "foreign matter is present" or "the possibility of foreign matter being present is high".

[0304] For example, when the Q value is adopted as the waveform attenuation index, TX compares the measured value of the Q value with a predetermined threshold value. The threshold value is set based on the measured value in the first detection state or a value obtained by adding a measurement error to the measured value.

[0305] When the measured value of the Q value is less than the threshold, it is judged that "foreign matter exists" or "the possibility of foreign matter exists is high". When the measured value of the Q value is greater than or equal to the threshold, it is judged that "foreign matter does not exist" or "the possibility of foreign matter exists is low".

[0306] The second threshold setting method is a method in which TX adjusts and decides the threshold based on information transmitted from RX. It should be noted that the difference from the first threshold setting method is that the value of the waveform attenuation index may differ depending on the RX of the power transmission target placed on TX.

[0307] The reason is that the electrical characteristics of the RX coupled via the power transmission antenna of the TX will affect the value of the waveform attenuation index. For example, when the Q value is used as the waveform attenuation index, the Q value measured by the TX when there is no foreign matter may be different depending on the RX placed on the TX.

[0308] Therefore, the RX holds the Q value information when the TX is placed on the TX without foreign matter for each TX, and notifies the TX of the Q value information. The TX adjusts and decides the threshold for each RX based on the Q value information received from the RX.

[0309] More specifically, in the negotiation phase, TX receives the FOD status packet having reference quality factor value information, and adjusts and decides the threshold in the Q value measurement method.

[0310] The reference quality factor value is a quality factor that can be measured by the terminal of the power transmitting antenna of the test TX when the RX is placed on the test TX and there is no foreign matter nearby.

[0311] TX considers that the reference quality factor value corresponds to "Q value information when RX is placed on TX without foreign matter", and uses the reference quality factor value to determine the threshold. That is, TX can adjust and determine the foreign matter judgment threshold based on the waveform attenuation method based on the reference quality factor value.

[0312] In addition, the reference quality factor value transmitted from RX to TX in the negotiation phase is information used for foreign object detection in the Q value measurement method that originally measures the Q value in the frequency domain.

[0313] However, when Q is used as a waveform decay indicator, the method of deriving Q is different, but it is also possible to use the waveform decay method that measures Q in the time domain, such as from Fig. 9 The Q value of the waveform is obtained according to formula (1).

[0314] Therefore, the threshold of the Q value of the waveform attenuation method can be set based on the reference quality factor value. In addition, the value of the waveform attenuation index obtained by adding a predetermined value (a value corresponding to the measurement error) to the reference quality factor value can be set as the foreign matter judgment threshold.

[0315] Thus, since TX sets the threshold of the Q value of the waveform attenuation method based on the information already transmitted from RX to TX in the negotiation phase, there is no need to perform processing such as new measurement processing for setting the threshold. As a result, the threshold can be set in a shorter time.

[0316] The third threshold setting method is a method in which TX measures the waveform attenuation index in the absence of foreign matter and TX adjusts and decides the threshold based on information related to the measurement result. Hereinafter, the timing for pre-measuring the waveform attenuation rate in the absence of foreign matter will be described.

[0317] When it is determined that no foreign matter exists as a result of foreign matter detection by the Q value measurement method in the negotiation phase of the WPC standard, a transition is made to the calibration phase and the power transmission phase.

[0318] In other words, the fact that the phase transitions to the phase after the negotiation phase indicates that it is determined that no foreign matter exists as a result of foreign matter detection by the Q value measurement method. In any of the negotiation phase, the calibration phase, and the power transmission phase, there is a high possibility that the waveform attenuation index may be measured without the presence of foreign matter.

[0319] Therefore, the timing for measuring the waveform attenuation index in the absence of foreign matter may be any of the negotiation phase, the calibration phase, and the power transmission phase.

[0320] For example, a case where the waveform attenuation index is measured in the power transmission stage is assumed. The timing for measuring the waveform attenuation index in the absence of foreign matter is set at the initial stage of the power transmission stage.

[0321] The reason is that the probability of foreign matter entering the vicinity of TX and RX increases as the time elapses from the time when the foreign matter is determined to be absent by the Q value measurement method. RX or TX assigns timing, and TX measures the waveform attenuation index at this time and sets the value of the waveform attenuation index as a threshold.

[0322] When RX assigns timing, RX notifies TX of the timing by transmitting a predetermined packet. In addition, when TX assigns timing, TX notifies RX of the timing by transmitting a predetermined packet. In addition, a value obtained by adding a predetermined value (a value corresponding to the measurement error) to the waveform attenuation index may be set as a foreign matter judgment threshold.

[0323] The fourth threshold setting method is a method in which TX adjusts and determines the threshold according to the transmitted power. The value of the waveform attenuation index may be different depending on the transmitted power of TX. The reason is that the heat generation and the characteristics of the TX circuit, etc. change with the size of the transmitted power of TX, and they affect the value of the waveform attenuation index.

[0324] TX can make more accurate foreign object judgments by measuring the waveform attenuation index of the transmitted power and adjusting and determining the threshold value based on the measurement results.

[0325] Fig.11 This is an explanatory diagram of a method for setting a threshold value for determining a foreign object in the TX transmission power in the waveform attenuation method. Fig.11 In FIG. 1 , the horizontal axis represents the transmitted electric power of the power transmission device 100 , and the vertical axis represents the waveform attenuation index (waveform attenuation rate) of the voltage waveform or the current waveform.

[0326] On the graph line indicated by the straight line segment 1102, point 1100 corresponds to the transmitted power value Pt1 and the waveform attenuation index δ1, and point 1101 corresponds to the transmitted power value Pt2 and the waveform attenuation index δ2. On the graph line, point 1103 corresponds to the transmitted power value Pt3 and the waveform attenuation index δ3.

[0327] First, RX performs control processing so that when power is transmitted from TX, RX is in a light load state. In the light load state, no power is supplied to the load of RX, only power below a threshold is supplied, or power within a predetermined range (hereinafter referred to as the "third range") is supplied.

[0328] The transmission power value of TX in this state is assumed to be Pt1. In addition, RX transmits a packet indicating a request for waveform attenuation index measurement to TX. When receiving the packet, TX stops transmission or reduces transmission power while controlling the load of RX to be in a light load state, and measures the waveform attenuation index δ1.

[0329] At this time, TX recognizes the transmission power value Pt1 and stores the calibration point CP 1100 in which the transmission power value Pt1 and the waveform attenuation index δ1 are associated in the memory. Next, RX controls the connected load state.

[0330] The connected load state is a state in which, when power is transmitted from TX, maximum power is supplied to the load of RX, or power greater than or equal to a predetermined threshold is supplied, or power within a predetermined range (hereinafter referred to as a "fourth range") is supplied.

[0331] Here, the “fourth range” is a wider power range than the “third range.” The transmission power value of TX in this state is assumed to be Pt2. In addition, RX transmits a packet for indicating a request for waveform attenuation index measurement to TX.

[0332] When receiving the packet, TX stops or reduces the power transmission while the load of RX is controlled to be in the connected load state, and measures the waveform attenuation index δ2. At this time, TX stores CP1101 in which the power transmission value Pt2 and the waveform attenuation index δ2 are associated in the memory.

[0333] Then, TX generates line segment 1102 by linear interpolation between CP 1100 and CP 1101. Line segment 1102 indicates the relationship between the transmission power in the first detection state where no foreign matter exists near TX and RX and the waveform attenuation index of the waveform observed by the power transmission antenna 105.

[0334] Therefore, TX can estimate the waveform attenuation index of the waveform observed by the power transmission antenna 105 for each power transmission value in the first detection state based on the line segment 1102. For example, in the case of the power transmission value Pt3, the waveform attenuation index is estimated to be δ3 based on the point 1103 on the line segment 1102 corresponding to Pt3.

[0335] TX can calculate a threshold value for judging the presence or absence of foreign matter for each transmission power value based on the estimation result. For example, a waveform attenuation index that is larger by a predetermined value (a value corresponding to the measurement error) than the estimation result of the waveform attenuation index of a certain transmission power value in the first detection state can be set as the foreign matter judgment threshold.

[0336] The CAL process performed by the power transmitting apparatus 100 and the power receiving apparatus 200 so that the power transmitting apparatus 100 acquires a combination of a transmission power value and a waveform attenuation index is hereinafter referred to as “CAL process of the waveform attenuation method”.

[0337] Although the measurement process is performed at two points of the transmitted power values ​​Pt1 and Pt2 in the above example, the waveform attenuation index of the transmitted power may be calculated by performing the measurement process at three or more points so that the accuracy is further improved.

[0338] After providing TX with a notification of a predetermined packet for instructing execution of control, RX can perform control in a light load state and control in a connected load state. In addition, either of the two controls can be performed first.

[0339] The process of calculating the threshold value for foreign object judgment for each load (or for each transmitted power value) described in this embodiment can be performed in the calibration phase. As described above, in the calibration phase, TX acquires data required for detecting foreign objects by the power loss method.

[0340] At this time, when the load state of RX is light load state and connected load state, TX obtains the received power value of each RX and data related to power loss. Therefore, when RX is in light load state and connected load state in the calibration phase, Fig.11 The measurements at CP 1100 and CP 1101 in can be performed together with the measurement of power loss.

[0341] For example, when a signal having first reference received power information has been received from RX, TX performs measurement at CP 1100 in addition to predetermined processing to be performed in the calibration phase. The first reference received power information is information related to RP1 specified in the WPC standard, but other messages may be used.

[0342] In addition, when a signal having the second reference power reception information is received from RX, TX performs measurement at CP 1101 in addition to the predetermined processing to be performed in the calibration phase. The second reference power reception information is information related to RP2 specified in the WPC standard, but other messages may be used. Since there is no need to provide separate periods for performing measurements at CP 1100 and CP 1101, measurements at CP 1100 and CP 1101 can be performed in a shorter time.

[0343] Therefore, TX adjusts and sets the threshold of the waveform attenuation index of the transmitted power based on information related to the waveform attenuation index measured by TX for the transmitted power. For example, when the Q value is used as the waveform attenuation index, TX compares the measured value of the Q value with the threshold determined by the above method.

[0344] When the measured value of the Q value is less than the threshold, it is judged that "foreign matter exists" or "there is a possibility that foreign matter exists". When the measured value of the Q value is greater than or equal to the threshold, it is judged that "foreign matter does not exist" or "the possibility that foreign matter exists is low". As described above, the threshold value of the transmitted power of TX is set, and more accurate foreign matter judgment can be performed.

[0345] The number of foreign body judgment thresholds set by the above method is not limited to one. Multiple thresholds may be set in stages. For example, the first threshold is set as a threshold for judging that "there is an abnormal state", the second threshold is set as a threshold for judging that "there is a high probability of an abnormal state", the third threshold is set as a threshold for judging that "there is a low probability of an abnormal state", and the fourth threshold is set as a threshold for judging that "there is no abnormal state".

[0346] In addition, there is a possibility that accuracy cannot be ensured by performing foreign object detection processing only once. For example, when a transmission power control process is performed once in foreign object detection that performs a waveform attenuation method, and foreign object judgment is performed based on the waveform attenuation index at this time, there is a possibility that the amplitude and phase of the transmission waveform during the transmission power control period may be disturbed.

[0347] There may be noise introduction during the transmission power control period and positional deviation of the RX placed on the TX, etc. In this case, when the value of the waveform attenuation index obtained from the transmission waveform during the primary transmission power control period is inaccurate, there is a possibility that misjudgment may occur in foreign matter judgment.

[0348] Therefore, the TX can perform multiple transmission power controls, measure the waveform attenuation index from the transmission power waveform during the multiple transmission power control periods, and perform more accurate foreign matter judgment based on the multiple measurement results.

[0349] Next, the first measurement method will be described as a method for measuring the coupling state index of the power transmitting antenna and the power receiving antenna. The measurement performed in the first measurement method is hereinafter referred to as the first measurement. In wireless power transmission, power is transmitted by electromagnetically coupling the power transmitting antenna 105 and the power receiving antenna 205.

[0350] A voltage is induced in the power receiving antenna 205 by passing an AC current through the power transmitting antenna 105 and changing the magnetic flux passing through the power receiving antenna 205. For example, when all (100%) of the magnetic flux generated by the power transmitting antenna passes through the power receiving antenna, a coupling coefficient (represented by k, and a value thereof is referred to as a k value) which is an indicator of the coupling state between the power transmitting antenna and the power receiving antenna is "k=1".

[0351] Furthermore, when 70% of the magnetic flux generated by the power transmitting antenna passes through the power receiving antenna, “k=0.7.” In this case, the remaining (30%) magnetic flux generated by the power transmitting antenna becomes leakage magnetic flux.

[0352] This is the magnetic flux that has not passed through the power receiving antenna within the magnetic flux generated by the power transmitting antenna. Therefore, when the coupling state between the power transmitting antenna and the power receiving antenna is appropriate and the k value is large, the transmission efficiency of the power transmitted from TX to RX is high. On the contrary, when the coupling state is not appropriate and the k value is small, the transmission efficiency of the power transmitted from TX to RX is low.

[0353] Factors that reduce the value of the coupling coefficient may be foreign matter (metal sheet, etc.) between the power transmitting antenna and the power receiving antenna and positional offset between the power transmitting antenna and the power receiving antenna. Alternatively, the factor may be an increase in the distance between the power transmitting antenna and the power receiving antenna.

[0354] If a foreign object is located between the power transmitting antenna and the power receiving antenna, heat may be generated in the foreign object. In addition, if the power transmitting antenna and the power receiving antenna are displaced or separated, leakage magnetic flux increases, which may cause loud noise in the surrounding environment.

[0355] When the k value is small, appropriate control is required to achieve safer and higher quality wireless power transmission. In this embodiment, a process for detecting the coupling state (including the coupling coefficient) between the power transmitting antenna and the power receiving antenna is performed, so that the detection accuracy of foreign objects and the detection accuracy in the case of positional offset or large distance are improved.

[0356] Will refer to Fig.12 (A) and (B) describe a method for measuring a coupling state index of a power transmitting antenna and a power receiving antenna. Fig.12 (A) is an illustrative equivalent circuit diagram of the first measurement method. The following shows the definitions of various quantities related to the power transmission antenna (power transmission coil) on the primary side (TX).

[0357] ·r1: Winding resistance of the power transmission antenna.

[0358] L1: Self-inductance of the power transmission antenna.

[0359] V1: The power transmission voltage (input voltage) applied to the power transmission antenna measured by the TX.

[0360] In addition, the definitions of various quantities related to the power receiving antenna (power receiving coil) on the secondary side (RX) are shown below.

[0361] ·r2: Winding resistance of the power receiving antenna.

[0362] L2: Self-inductance of the receiving antenna.

[0363] V2: The power receiving voltage (output voltage) applied to the power receiving antenna measured by RX.

[0364] The coupling coefficient k between the power transmitting antenna and the power receiving antenna can be calculated by the following equation (2).

[0365]

[0366] When TX calculates the coupling coefficient k, RX notifies TX of the measured power receiving voltage V2 and the value of the self-inductance L2 of the power receiving antenna stored in advance by RX. TX calculates the k value using the measured power transmitting voltage V1, the value of the self-inductance L1 of the power transmitting antenna stored in advance, and the power receiving voltage V2 and the value of the self-inductance L2 received from RX.

[0367] Alternatively, RX may notify TX of a constant and V2 calculated using both or one of L1 and L2, and TX may calculate the k value using the constant and V2 received from RX and the power transmission voltage V1 measured by TX.

[0368] On the other hand, when RX calculates the coupling coefficient k, TX notifies RX of the measured power transmission voltage V1 and the pre-stored value of the self-inductance L1 of the power transmission antenna. RX calculates the k value using the measured power reception voltage V2, the pre-stored value of the self-inductance L2 of the power reception antenna, and the power transmission voltage V1 and self-inductance L1 values ​​received from TX.

[0369] Alternatively, TX may notify RX of V1 and a constant calculated using both or one of L1 and L2, and RX may calculate the k value using the constant received from TX, V1, and the power reception voltage V2 measured by RX.

[0370] For the power transmission voltage V1, TX actually measures the voltage applied to the power transmission antenna, or TX calculates the voltage according to the setting value of the power transmission power. Alternatively, the power transmission voltage V1 may be used as the setting value of the power transmission voltage when transmitting power.

[0371] Furthermore, a power transmission voltage (denoted by V3 ) applied to a circuit (eg, inverter) provided in the power transmission unit 103 of TX and a power transmission voltage V1 applied to the power transmission antenna can be obtained from the voltage applied between both ends of the resonance capacitor 107 .

[0372] Here, the power transmission voltage V3 applied to the circuit provided in the TX power transmission unit 103 is, for example, an inverter input voltage input to an inverter provided in the TX power transmission unit 103 or an inverter output voltage output by the inverter.

[0373] In this case, TX can also calculate the transmission voltage V3 according to the set value of the transmission power. Alternatively, TX can actually measure the transmission voltage V3 and the voltage applied between both ends of the resonance capacitor 107, and obtain the transmission voltage V1 using the measured voltage. Alternatively, TX can transmit the values ​​of the measured transmission voltage V3 and the voltage applied between both ends of the resonance capacitor 107 to RX, and RX can calculate the k value by obtaining the transmission voltage V3.

[0374] In addition, when TX or RX performs the first measurement, RX can control by turning off the third switch unit 213 so that the terminal of the power receiving antenna 205 is in an open circuit state. Fig.12 As shown in (A), both ends of the power receiving antenna can be placed in an open circuit state.

[0375] The coupling coefficient k can be measured with higher accuracy because the first measurement is not affected by the resonance capacitor 211, the power receiving unit 203, the charging unit 206, and the battery 207. In addition, the power receiving voltage (represented by V4) applied to the circuit (e.g., the rectifying unit) provided in the power receiving unit 203 of RX and the power receiving voltage V2 applied to the power receiving antenna can be obtained from the voltage applied between both ends of the resonance capacitor 211.

[0376] Here, the power receiving voltage V4 applied to the circuit provided in the power receiving unit 203 of RX is, for example, an input voltage specific to the rectifying unit input to the rectifying unit provided in the power receiving unit 203 of RX. Alternatively, the power receiving voltage V2 applied to the power receiving antenna may be obtained from the power receiving voltage (represented by V5) of the circuit (e.g., the rectifying unit) of the power receiving unit 203 of RX and the voltage applied between both ends of the resonant capacitor 211.

[0377] Here, the power receiving voltage V5 applied to the circuit provided in the power receiving unit 203 of the RX is, for example, an output voltage specific to the rectifying unit output from the rectifying unit provided in the power receiving unit 203 of the RX. In this case, the RX can actually measure the power receiving voltage V4 and the voltage applied between both ends of the resonance capacitor 211, and obtain the power receiving voltage V2 using the measured voltages.

[0378] Alternatively, RX may actually measure the power receiving voltage V5 and the voltage applied between both ends of the resonance capacitor 211, and use the measured voltage to obtain the power receiving voltage V2. Alternatively, RX may transmit the values ​​of the measured power receiving voltage V4 and the voltage applied between both ends of the resonance capacitor 211 to TX, and TX may calculate the k value by obtaining the power receiving voltage V2.

[0379] Alternatively, RX may transmit the measured power receiving voltage V5 and the value of the voltage applied between both ends of the resonance capacitor 211 to TX, and TX may calculate the k value by obtaining the power receiving voltage V2. Alternatively, when TX or RX performs the first measurement, RX may control so that the state is a light load state or a connected load state.

[0380] By making the load state of RX uniform, the coupling coefficient k can be measured with higher accuracy. Alternatively, TX or RX may control so that RX performs the first measurement in both the light load state and the connected load state.

[0381] Alternatively, TX or RX may control so that RX performs the first measurement in each of three or more load states. By measuring the coupling state in a plurality of load states of RX and judging the coupling state based on the load state, the coupling state can be judged with higher accuracy.

[0382] As an index indicating the electromagnetic coupling state between the power transmitting antenna and the power receiving antenna, there are a plurality of quantities other than the coupling coefficient, and they are collectively referred to as "coupling state indexes" in this embodiment. Each coupling state index has a value corresponding to the electromagnetic coupling state between the power transmitting antenna and the power receiving antenna. Likewise, even if a coupling state index other than the coupling coefficient is used, the contents of this embodiment can be applied.

[0383] For example, as a method of calculating the coupling state index, there is a method of using a transmission voltage V3 applied to a circuit (e.g., inverter) provided in the power transmission unit 103 of TX and a reception voltage (represented by V4) applied to a circuit (e.g., rectifier) ​​provided in the power reception unit 203 of RX.

[0384] Here, the power transmission voltage V3 applied to the circuit provided in the TX power transmission unit 103 is, for example, an inverter input voltage input to an inverter provided in the TX power transmission unit 103 or an inverter output voltage output by the inverter.

[0385] Here, the power receiving voltage V4 applied to the circuit provided in the power receiving unit 203 of RX is, for example, an input voltage specific to the rectifying unit provided in the power receiving unit 203 of RX. Using these, calculation processing for the coupling state index between the power transmitting antenna and the power receiving antenna can be performed.

[0386] Alternatively, the coupling state index between the power transmitting antenna and the power receiving antenna may be calculated using a power transmission voltage V3 applied to a circuit (e.g., an inverter) provided in the power transmitting unit 103 of TX and a power receiving voltage (represented by V5) of a circuit (e.g., a rectifier) ​​provided in the power receiving unit 203 of RX.

[0387] Here, the power receiving voltage V5 applied to the circuit provided in the power receiving unit 203 of RX is, for example, an output voltage specific to the rectifying unit output from the rectifying unit provided in the power receiving unit 203 of RX. Alternatively, the voltage is a voltage applied to a load (charging unit or battery).

[0388] TX notifies RX of the power transmission voltage V3, and RX can calculate the coupling state index using V3 and V4 or V5 indicated in the notification. At this time, TX notifies RX of a constant calculated using the electrical characteristics of the power transmission antenna (e.g., L1), and RX can calculate the coupling state index using the constant.

[0389] Alternatively, RX notifies TX of the power receiving voltage V4 or the power receiving voltage V5, and TX calculates the coupling state index using V4 or V5 indicated in the notification and V3. At this time, RX notifies TX of a constant calculated using the electrical characteristics of the power receiving antenna (e.g., L2), and TX can calculate the coupling state index using the constant.

[0390] TX and RX transmit and receive voltage values ​​from V1 to V5, values ​​of self-inductances L1 and L2, and information about constants indicating electrical characteristics of the power transmitting and receiving antennas. Hereinafter, the timing for measuring voltage values ​​and the timing for transmitting and receiving each information item will be described.

[0391] For example, the measurement of each voltage value is performed in the Ping phase. In the Ping phase, TX transmits a digital Ping to RX. Therefore, any voltage value among V1, V2, V3, V4, and V5 generated when transmitting the digital Ping can be used. In the Ping phase, TX and RX measure any value from V1 to V5, and store and hold the measured value in the memory 106 or the memory 208.

[0392] TX transmits a predetermined transmission request packet for requesting RX to transmit a packet including information related to any one or all of the voltage values ​​of V2, V4, and V5. When receiving the transmission request packet, RX transmits a predetermined packet having information related to any one or all of the voltage values ​​of V2, V4, and V5 to TX.

[0393] TX receives a predetermined packet having information on any one or all of the voltage values ​​of V2, V4, and V5 indicated in the notification from RX, and stores the information in the memory 106. The information included in the predetermined packet may include not only the voltage of RX but also information such as received power, required received power value, value of self-inductance L2, and constants calculated using electrical characteristics of the power receiving antenna.

[0394] In addition, the information may also include information related to the temperature of the RX. The TX may receive the information from the RX and use the information and the calculated coupling status indicator to perform more appropriate control.

[0395] As a predetermined packet, a signal strength data packet may be used to notify TX of information related to RX. Alternatively, the predetermined packet may be an identification data packet or an extended identification data packet in the I&C phase.

[0396] Alternatively, the packet may be a configuration data packet.Alternatively, the packet may be a packet in a calibration phase or a power transfer phase.

[0397] That is, RP1, RP2, and RP0 can be used. In addition, TX is not limited to the example of using the voltage value generated when transmitting the digital Ping. In the selection phase, TX can use any voltage value from V1 to V5 generated when transmitting the analog Ping. Alternatively, any voltage value from V1 to V5 generated when TX transmits power to RX in the power transmission phase can be used.

[0398] RX transmits a predetermined transmission request packet for requesting TX to transmit a packet including information related to one or both of the voltage values ​​of V1 and V3. When receiving the transmission request packet, TX transmits a predetermined packet having information related to one or both of the voltage values ​​of V1 and V3 to RX.

[0399] RX receives a predetermined packet having information on one or both of the voltage values ​​of V1 and V3 indicated in the notification from TX, and stores the information in the memory 208. The information included in the predetermined packet may include not only the voltage of TX but also information such as a transmission power value, an available transmission power value, a value of the self-inductance L1, and constants calculated using the electrical characteristics of the power transmission antenna.

[0400] In addition, the foreign matter detection result of the above-mentioned foreign matter detection method (power loss method, Q value measurement method or waveform attenuation method) and information related to the temperature of TX can be included. RX can receive information from TX and use the information and the calculated coupling state index to perform more appropriate control.

[0401] In addition, a power transmitter capabilities (CAP) data packet may be used as a predetermined packet to inform the RX of information related to the TX.

[0402] Alternatively, a power transmitter identification (ID) packet may be used to notify RX of information related to TX. In addition, TX is not limited to the example of using a voltage value generated when transmitting a digital Ping.

[0403] In the selection phase, TX may use any voltage value from V1 to V5 generated when transmitting a simulated Ping. Alternatively, any voltage value from V1 to V5 generated when TX transmits power to RX in the power transfer phase may be used.

[0404] When performing the first measurement, RX may control so that the third switch unit 213 between the resonance capacitor 211 and the power receiving unit 203 is turned off, and the terminals of the circuit including the power receiving antenna 205 and the resonance capacitor 211 are in an open state.

[0405] Thus, since the first measurement is not affected by the power receiving unit 203 , the charging unit 206 , and the battery 207 in the implementation of the first measurement method, the coupling state index can be measured with higher accuracy.

[0406] Next, the second measurement method will be described as another example of the coupling state index measurement method of the power transmitting antenna and the power receiving antenna. The measurement performed in the second measurement method is hereinafter referred to as the second measurement. Fig.12 (B) is an illustrative equivalent circuit diagram of the second measurement method.

[0407] r1, r2, L1 and L2 Fig.12 The following are definitions of various quantities related to the power transmission antenna (coil) on the primary side (TX).

[0408] V6: Input voltage of the power transmitting antenna (power transmitting voltage) when the power receiving antenna is in a short-circuited state.

[0409] V7: Input voltage of the power transmitting antenna (power transmitting voltage) when the power receiving antenna is in an open circuit state.

[0410] I1: Current flowing through the power transmitting antenna when the power receiving antenna is in a short-circuit state.

[0411] I2: Current flowing through the power transmitting antenna when the power receiving antenna is in an open circuit state.

[0412] The coupling coefficient k can be calculated by the following formula (3).

[0413]

[0414] Lsc in equation (3) represents the inductance of the power transmitting antenna when both ends of the power receiving antenna are short-circuited. For example, the control unit 201 turns the third switch unit 213 and the second switch unit 210 to an ON state (short-circuited state).

[0415] In this state, the Lsc value can be obtained by measuring the inductance value of the power transmission antenna. The inductance value of the power transmission antenna can be obtained from the input voltage V6 and current I1 of the power transmission antenna.

[0416] Lopen in equation (3) represents the inductance of the power transmitting antenna when both ends of the power receiving antenna are open. For example, the control unit 201 makes the third switch unit 213 in the OFF state (open state). In this state, the Lopen value can be obtained by measuring the inductance value of the power transmitting antenna.

[0417] In the second measurement method, the coupling state index (coupling coefficient) can be obtained from the input voltage and current of the power transmitting antenna when both ends of the power receiving antenna are short-circuited and when they are open-circuited.

[0418] In addition, TX can calculate the coupling state index based on the power transmission voltage and current applied to the circuit (e.g., inverter) included in the power transmission unit 103. In this case, the input voltage V6 or V7 is the power transmission voltage applied to the circuit (e.g., inverter) included in the power transmission unit 103, for example, the inverter input voltage or the inverter output voltage.

[0419] In addition, the input voltage V6 or V7 may be a voltage applied between two terminals of a series resonant circuit consisting of a power transmission antenna and a resonant capacitor. Alternatively, the power transmission voltage applied to a circuit (e.g., an inverter) provided in the power transmission unit 103 and the voltage applied between both ends of the resonant capacitor 107 may be measured, and the voltage applied to the power transmission antenna may be calculated based on the measurement result.

[0420] That is, the coupling state index can be obtained from the measurement result of the power transmission voltage applied to the circuit (e.g., inverter) included in the power transmission unit 103 and the voltage applied between both ends of the resonance capacitor 107. In this case, the power transmission voltage applied to the circuit (e.g., inverter) included in the power transmission unit 103 can be calculated by the TX according to the setting value of the power transmission power.

[0421] In addition, Fig.12 In (B), the current I1 or I2 is not limited to the current flowing through the power transmission antenna, but may be, for example, a current flowing through a circuit (e.g., an inverter) including the power transmission unit 103. Here, the current flowing through the circuit provided in the power transmission unit 103 of the TX is, for example, an inverter input current or an inverter output current.

[0422] The example has been described in which the control unit 201 realizes the open state and the short state of the power receiving antenna according to the control of the second switch unit 210 and the third switch unit 213. These states can be realized in the power receiving unit 203.

[0423] In addition, instead of the short circuit state, a light load state may be used. In addition, instead of the open circuit state, a connected load state may be used.

[0424] In the second measurement method, TX can calculate the coupling state index by measuring the input voltages V6 and V7 and the currents I1 and I2. Therefore, since information such as the voltage value measured by RX and the inductance value of the power receiving antenna is not required, it is not necessary to provide notification of this information from RX to TX.

[0425] However, when TX measures input voltage V6 and current I1, RX needs to SHORT the two terminals of the circuit including the power receiving antenna. In addition, when TX measures input voltage V7 and current I2, RX needs to OPEN the two terminals of the circuit including the power receiving antenna.

[0426] That is, according to the timing at which TX measures the input voltage and current, RX needs to control the two terminals of the circuit including the power receiving antenna so that they are in a SHORT (short circuit) or OPEN (open circuit) state.

[0427] If the control is completed, TX performs measurement. Regarding the measurement timing, TX performs decision processing and provides notification to RX, or RX performs decision processing and provides notification to TX. In addition, when the control is completed so that both terminals of the circuit including the power receiving antenna are in the SHORT (short circuit) or OPEN (open circuit) state, RX provides notification to TX.

[0428] These notifications are provided according to communication based on the WPC standard performed between the first communication unit 104 of TX and the first communication unit 204 of RX, or communication based on a standard other than the WPC standard performed between the second communication unit 109 of TX and the second communication unit 212 of RX.

[0429] For example, the input voltages V6 and V7 and the currents I1 and I2 are measured in the Ping phase. In the Ping phase, the TX transmits a digital Ping to the RX. Therefore, the values ​​of V6 and V7 and the currents I1 and I2 generated when the digital Ping is transmitted can be used.

[0430] In the Ping phase, TX acquires the values ​​of V6, V7, I1, and I2, holds these values ​​in the memory 106, and calculates the coupling state index. In addition, TX is not limited to the example of using the voltage value and current value generated when transmitting the digital Ping.

[0431] For example, in the selection phase, the values ​​of V6, V7, I1, and I2 generated when TX transmits a simulated Ping may be used. Alternatively, the voltage values ​​V6, V7, I1, and I2 generated when TX transmits power to RX in the power transfer phase may be used.

[0432] In the present disclosure, the first measurement method or the second measurement method can be applied to the coupling state index measurement method of the power transmitting antenna and the power receiving antenna. Hereinafter, a method for setting a state judgment threshold of the coupling state index obtained by the first measurement method or the second measurement method will be described.

[0433] The state determination is determination related to detection of foreign matter between the power transmitting antenna and the power receiving antenna, determination related to detection of positional displacement between the power transmitting antenna and the power receiving antenna, or determination related to detection of separation between the power transmitting antenna and the power receiving antenna.

[0434] The first measurement method or the second measurement method may be performed, and the presence or absence of a state abnormality may be determined using the state determination threshold. Hereinafter, the first to fourth threshold setting methods will be described.

[0435] The first threshold setting method is a method of setting the value of the coupling state index when there is no state abnormality as the threshold of the coupling state index used for state detection between the power transmitting antenna and the power receiving antenna.

[0436] In the state detection, for example, judgment results such as "there is a state abnormality", "the possibility of a state abnormality is high", "the possibility of a state abnormality is low", or "there is no state abnormality" can be obtained. Assume that the RX is placed on the test TX and there is no state abnormality between the power transmitting antenna and the power receiving antenna.

[0437] In this case, the value of the coupling state index between the test TX including the power transmitting antenna and the RX including the power receiving antenna can be set as a threshold. The RX holds the value (threshold) of the coupling state index measured in advance in a memory, and the RX notifies the TX of the threshold.

[0438] TX uses a threshold value to perform judgment processing related to state detection. The threshold value may be included in the FOD status data packet specified in the WPC standard, and RX transmits the FOD status data packet to TX. Alternatively, the value of the coupling state index between the power transmitting antenna and the power receiving antenna for obtaining a predetermined power transmission efficiency may be set as the threshold value.

[0439] In the state detection, for example, the following judgment results can be obtained.

[0440] "The expected power transmission efficiency cannot be achieved" or "The coupling between the power transmitting antenna and the power receiving antenna is weak."

[0441] "There is a high possibility that the predetermined power transmission efficiency cannot be obtained" or "There is a high possibility that the coupling between the power transmitting antenna and the power receiving antenna will be weak."

[0442] "There is a high probability that a predetermined power transmission efficiency can be obtained" or "There is a probability that the coupling state between the power transmitting antenna and the power receiving antenna is appropriate."

[0443] "A predetermined power transmission efficiency can be obtained" or "The coupling state between the power transmitting antenna and the power receiving antenna is appropriate."

[0444] Here, it is assumed that the RX is placed on the test TX, there is no state abnormality between the power transmitting antenna and the power receiving antenna, and a predetermined power transmission efficiency is obtained. In this case, the value of the coupling state index between the test TX including the power transmitting antenna and the RX including the power receiving antenna can be set as a threshold.

[0445] RX holds the value of the coupling state indicator measured in advance as a threshold in a memory and notifies TX of the threshold. TX uses the threshold to perform judgment processing related to state detection. The threshold may be included in the FOD status data packet specified in the WPC standard, and RX may transmit the FOD status data packet to TX.

[0446] The second threshold setting method is a method in which TX and RX set the coupling state index measured by the first measurement method or the second measurement method as a threshold in a predetermined state. The predetermined state is a state in which there is no abnormality between the power transmitting antenna and the power receiving antenna.

[0447] Among the methods for confirming the status, status detection of TX and RX can be used, such as foreign object detection by power loss method, foreign object detection by waveform attenuation method, foreign object detection by Q value measurement method, and foreign object detection based on the temperature of TX or RX to be described below.

[0448] As a result, when it is determined that there is no abnormal state, it can be confirmed with high probability that there is no abnormal state between the power transmitting antenna and the power receiving antenna. That is, this confirmation is performed by a method and means other than the first measurement method or the second measurement method.

[0449] As a result, if it is determined that “there is no state abnormality” (or “there is no foreign matter”), the coupling state index is measured using the first measurement method or the second measurement method, and an appropriate threshold is set based on the measurement result.

[0450] For example, in the WPC standard, during the negotiation phase or the renegotiation phase, a foreign object detection process using the Q value measurement method is performed. When it is determined as "no state abnormality exists" (or "no foreign object exists") as a result of the foreign object detection process, the first measurement method or the second measurement method is used to measure the coupling state index in the negotiation phase, the renegotiation phase, or a subsequent phase.

[0451] Based on the measurement result, a more appropriate threshold value can be set. In addition, during the power transmission phase, a foreign object detection process by a power loss method is performed. After the foreign object detection process is performed, the coupling state index is measured using the first measurement method or the second measurement method, and a more appropriate threshold value can be set based on the measurement result.

[0452] Alternatively, in the selection phase or the Ping phase, a foreign body detection process may be performed using a quality factor, etc. In this case, after the phase of performing the foreign body detection process, the coupling state index is measured using the first measurement method or the second measurement method, and an appropriate threshold value may be set based on the measurement result.

[0453] Alternatively, during the power transmission phase, a foreign object detection process by the above-mentioned waveform attenuation method is performed. After the foreign object detection process is performed, the coupling state index is measured using the first measurement method or the second measurement method, and a more appropriate threshold value can be set based on the measurement result.

[0454] Next, we will refer to Fig.13 A third threshold setting method is described. Fig.13 This is a diagram for explaining the threshold setting method in state detection using the coupling state indicator. Fig.13 , the horizontal axis represents the transmitted power, and the vertical axis represents the coupling state index.

[0455] On the graph line indicated by a straight line segment 1202 , a point 1200 corresponds to the transmitted power value Pt1 and the coupling state index value k1 , and a point 1201 corresponds to the transmitted power value Pt2 and the coupling state index value k2 .

[0456] On the graph line, point 1203 corresponds to the transmitted power value Pt3 and the coupling state index value k3. For calculation of each coupling state index value, the first measurement method or the second measurement method described above can be used.

[0457] like Figure 3 As shown, since the charging unit 206 and the battery 207 are connected to the power receiving unit 203 of the RX as loads, the calculated coupling state index value changes with the load state. It is necessary to set a threshold for the coupling state index so that whether there is a state abnormality is determined according to the load state.

[0458] First, when power is transmitted from TX, RX controls so that the load is in a light load state. The light load state is a state in which power is not supplied to the load of RX or only power less than or equal to a threshold is supplied thereto.

[0459] Alternatively, the state is a load state in which the received power value of RX is within a prescribed predetermined range (hereinafter referred to as "fifth range"). The transmitted power value of TX in this state is represented by Pt1. RX transmits a packet indicating a request for coupling state index measurement to TX.

[0460] Alternatively, TX transmits a packet indicating a request for coupling state index measurement to RX. In this state, TX and RX measure the power transmission voltage on the TX side and the power reception voltage on the RX side.

[0461] TX and RX exchange information such as the values ​​of V1 to V7, the values ​​of self-inductances L1 and L2, or constants calculated using the electrical characteristics of the power transmitting antenna and the power receiving antenna, and TX or RX calculates a coupling state index value k1.

[0462] When RX calculates the coupling state index value k1, it provides notification of the calculation result to TX. When TX calculates the coupling state index value k1, it provides notification of the calculation result and Pt1 to RX. At this time, TX recognizes the transmission power value Pt1 and stores the CP 1200 associated with Pt1 and k1 in the memory. Alternatively, RX stores the CP 1200 associated with Pt1 and k1 in the memory.

[0463] Next, RX performs control so that the load of RX is in a connected load state when power is transmitted from TX. The connected load state is a state in which the load of RX is supplied with maximum power or with power greater than or equal to a threshold.

[0464] Here, the "maximum power" is power having a value close to the reference power. Alternatively, the state is a load state in which the received power value of the RX is within a prescribed predetermined range (hereinafter referred to as a "sixth range").

[0465] The power value in the sixth range is greater than the power value in the fifth range. The transmission power value of TX in this state is represented by Pt2. RX transmits a packet indicating a request for coupling state index measurement to TX.

[0466] Alternatively, TX transmits a packet indicating a request for coupling state index measurement to RX. In this state, TX and RX measure the power transmission voltage on the TX side and the power reception voltage on the RX side.

[0467] TX and RX exchange information such as the values ​​of V1 to V7, the values ​​of self-inductances L1 and L2, or constants calculated using the electrical characteristics of the power transmitting antenna and the power receiving antenna, and TX or RX calculates a coupling state index value k2.

[0468] When RX calculates the coupling state index value k2, it provides notification of the calculation result to TX. When TX calculates the coupling state index value k2, it provides notification of the calculation result and Pt2 to RX. TX stores Pt2 and CP 1201 associated with k2 in the memory.

[0469] Alternatively, RX stores CP 1201 associated with Pt2 and k2 in memory. Subsequently, TX performs linear interpolation between CP 1200 and CP 1201 to generate line segment 1202.

[0470] Line segment 1202 indicates the relationship between the transmission power and the coupling state index when there is no abnormality in the vicinity of TX and RX. TX can use line segment 1202 to estimate the coupling state index value for each transmission power value when there is no abnormality in the vicinity of TX and RX.

[0471] For example, assume that the transmitted power value is Pt3. In this case, the coupling state index value k3 can be estimated from the point 1203 corresponding to the transmitted power value Pt3 on the line segment 1202. TX can calculate a threshold value for determining the presence or absence of state abnormality for each transmitted power value based on the estimation result.

[0472] For example, a coupling state index value obtained by adding a predetermined value (a value corresponding to the measurement error) to an estimation result of the coupling state index value when there is no state abnormality for a certain transmitted power value may be set as the determination threshold.

[0473] Therefore, the CAL process performed by the power transmitting device 100 and the power receiving device 200 so that the power transmitting device 100 acquires a combination of the transmission power value and the coupling state index value is referred to as “CAL process of the coupling state index measurement method”.

[0474] In addition, after notifying TX to perform control, RX can perform control in which the load is in a light load state and control in which the load is in a connected load state. In addition, either of these two controls can be performed first.

[0475] In the present embodiment, for example, an operation for calculating a state detection determination threshold for each load (or for each transmitted power value) is performed in the calibration phase. In the calibration phase, TX acquires data required for detecting foreign matter by the power loss method.

[0476] At this time, TX acquires data of the amount of power loss when the load state of RX is the light load state and when the load state of RX is the connected load state. Therefore, when RX is in the light load state and the connected load state in the calibration phase, Fig.13 The measurement processing at CP 1200 and CP 1201 in can be performed together with the measurement of power loss.

[0477] That is, when having received the first reference received power information from RX, TX performs measurement processing at CP 1200 in addition to predetermined processing to be performed in the calibration phase. The first reference received power information is information based on RP1 specified in the WPC standard, but other messages may be used.

[0478] In addition, when the second reference received power information has been received from RX, TX performs measurement processing at CP 1201 in addition to the predetermined processing to be performed in the calibration phase. The second reference received power information is information based on RP2 specified in the WPC standard, but other messages may be used. Therefore, since there is no need to set periods for measurement processing at CP 1200 and CP 1201, respectively, measurement processing at CP 1200 and CP 1201 can be performed in a shorter time.

[0479] The fourth threshold setting method is a method in which TX or RX sets a threshold in advance for a coupling state index having a value within a predetermined range. The threshold is a common value that does not depend on RX serving as a power transmission target, and TX or RX maintains a prescribed predetermined value.

[0480] In addition, the threshold value may be a fixed value that does not depend on the situation, or may be a variable value determined by TX or RX according to the situation. For example, if the coupling state index is the coupling coefficient k, the range of the k value is "0≤k≤1". For example, TX or RX determines that "there is a state abnormality" in the case of "0≤k<0.2", and determines that "the possibility of a state abnormality is high" in the case of "0.2≤k<0.5".

[0481] TX or RX determines that "the possibility of state abnormality is low" when "0.5≤k<0.8", and determines that "there is no state abnormality" when "0.8≤k≤1". Data of the condition of the k value is stored in advance in the memory, and the determination process is performed based on the data.

[0482] Alternatively, for example, in the case of “0≤k<0.2”, TX or RX determines that “predetermined power transmission efficiency cannot be obtained” or “coupling between the power transmitting antenna and the power receiving antenna is weak”.

[0483] When “0.2≤k<0.5”, TX or RX determines that “it is highly likely that the predetermined power transmission efficiency cannot be obtained” or “there is a possibility that the coupling between the power transmitting antenna and the power receiving antenna is weak”.

[0484] When “0.5≤k<0.8”, TX or RX determines that “it is highly likely that a predetermined power transmission efficiency can be obtained” or “there is a possibility that the coupling state between the power transmitting antenna and the power receiving antenna is appropriate”.

[0485] When "0.8≤k≤1", TX or RX determines that "predetermined power transmission efficiency can be obtained" or "the coupling state between the power transmitting antenna and the power receiving antenna is appropriate". Data of the k value condition is pre-stored in the memory, and the determination process is performed based on the data.

[0486] In addition, even in the setting of the judgment threshold value related to the state detection using the coupling state index, a value obtained by adding a predetermined value (a value corresponding to the measurement error) to the coupling state index value calculated based on the measurement result or the received information can be set as the judgment threshold value. In addition, the number of threshold values ​​is not limited to one, and a plurality of threshold values ​​can be set in stages as described above.

[0487] Next, the timing for calculating the coupling state between the power transmitting antenna and the power receiving antenna using the first measurement method or the second measurement method will be described. The calculation (measurement) of the coupling state is performed by transmitting a predetermined packet from RX to TX.

[0488] Here, the predetermined packet is a signal strength data packet transmitted from RX to TX. Alternatively, the predetermined packet may be an identification data packet, an extended identification data packet or a configuration data packet in the I&C phase.

[0489] Alternatively, the predetermined packet may be a packet in a calibration phase or a power transfer phase. That is, the predetermined packet may be RP1, RP2, and RP0.

[0490] When a predetermined packet has been received from RX, TX calculates the coupling state index between the power transmitting antenna and the power receiving antenna. In addition, TX makes a judgment by comparing the judgment threshold value set by the above method with the calculated coupling state index.

[0491] When it is determined that there is no state abnormality, TX transmits an affirmative response ACK or state information indicating that "there is no state abnormality" to RX. When it is determined that "the possibility of state abnormality is low" or "the possibility of state abnormality is high", TX transmits state information indicating the respective judgment results to RX. When it is determined that there is a state abnormality, TX transmits a negative response NAK or state information indicating that there is a state abnormality to RX.

[0492] Alternatively, when determining that "predetermined power transmission efficiency can be obtained" or "the coupling state between the power transmitting antenna and the power receiving antenna is appropriate", TX transmits an affirmative response ACK or status information indicating the determination result to RX.

[0493] When it is determined that "there is a high possibility that a predetermined power transmission efficiency can be obtained" or "there is a possibility that the coupling state between the power transmitting antenna and the power receiving antenna is appropriate", TX transmits status information indicating the determination result to RX.

[0494] When determining that "there is a high possibility that the predetermined power transmission efficiency cannot be obtained" or "there is a possibility that the coupling between the power transmitting antenna and the power receiving antenna will be weak", TX transmits status information indicating the determination result to RX.

[0495] When determining that "predetermined power transmission efficiency cannot be obtained" or "coupling between the power transmitting antenna and the power receiving antenna is weak", TX transmits a negative response NAK to RX, or transmits status information indicating the determination result to RX.

[0496] The status information is, for example, numerical information corresponding to the status, and is as follows.

[0497] State information "0" corresponds to a result of determination that "there is no state abnormality", "predetermined power transmission efficiency can be obtained", or "the coupling state between the power transmitting antenna and the power receiving antenna is appropriate".

[0498] State information "1" corresponds to a result determined as "low possibility of state abnormality", "high possibility of being able to obtain a predetermined power transfer efficiency", or "possibility that the coupling state between the power transmitting antenna and the power receiving antenna is appropriate".

[0499] State information "2" corresponds to a result determined as "high possibility of abnormal state", "high possibility of failure to obtain predetermined power transmission efficiency", or "there is a possibility that coupling between the power transmitting antenna and the power receiving antenna will be weak".

[0500] State information "3" corresponds to a result determined as "abnormality in state exists", "predetermined power transmission efficiency cannot be obtained", or "coupling between the power transmitting antenna and the power receiving antenna is weak".

[0501] Alternatively, the calculation (measurement) of the coupling state is performed by TX transmitting a predetermined packet to RX. Here, the predetermined packet is a power transmitter capability (CAP) data packet transmitted by TX to RX.

[0502] Alternatively, the packet is a power transmitter identification (ID) data packet. When having received a predetermined packet from TX, RX calculates a coupling state index between the power transmitting antenna and the power receiving antenna.

[0503] In addition, RX makes a judgment by comparing the judgment threshold set by the above method with the calculated coupling state index. When it is judged that there is no state abnormality, RX transmits a predetermined packet including state information indicating the judgment result to TX.

[0504] When it is determined that "the possibility of state abnormality is low" or "the possibility of state abnormality is high", RX transmits a predetermined packet including state information indicating the respective determination results to TX. When it is determined that "there is state abnormality", RX transmits a predetermined packet including state information indicating the determination result to TX.

[0505] Alternatively, when it is determined that "predetermined power transmission efficiency can be obtained" or "the coupling state between the power transmitting antenna and the power receiving antenna is appropriate", RX transmits status information indicating the determination result to TX.

[0506] When determining that "there is a high possibility that a predetermined power transmission efficiency can be obtained" or "there is a possibility that the coupling state between the power transmitting antenna and the power receiving antenna is appropriate", RX transmits status information indicating the determination result to TX.

[0507] When determining that "there is a high possibility that the predetermined power transmission efficiency cannot be obtained" or "there is a possibility that the coupling between the power transmitting antenna and the power receiving antenna will be weak", RX transmits status information indicating the determination result to TX.

[0508] When it is determined that "predetermined power transmission efficiency cannot be obtained" or "coupling between the power transmitting antenna and the power receiving antenna is weak", RX transmits status information indicating the determination result to TX. Examples of the status information are as described above.

[0509] Next, a first method of placement of TX detection RX when coupling between the power transmitting antenna and the power receiving antenna is weak will be described.

[0510] In a wireless charging system based on the WPC standard, TX and RX generally have a power transmission antenna and a power receiving antenna facing each other. In addition, the distance from the power receiving antenna to the outside of the housing of RX and the distance from the power transmission antenna to the outside of the housing of TX are specified in the WPC standard. A configuration in which the distance between the power transmission antenna and the power receiving antenna is within a predetermined range is adopted. Specifically, reference is made to Fig.14 A description is given of (A) to (D).

[0511] Fig.14 (A) shows an example in which the shape of the housing exterior near the power receiving antenna of RX is a plane and the shape of the housing exterior near the power transmitting antenna of TX is a plane. In this case, a configuration in which the distance between the power transmitting antenna and the power receiving antenna is within a predetermined range can be adopted.

[0512] Fig.14 (B) shows an example in which the shape of the housing exterior near the power receiving antenna of RX is a curved surface and the shape of the housing exterior near the power transmitting antenna of TX is a flat surface. When the power receiving antenna is arranged along the housing shape for TX, a configuration in which the distance between the central part of the power receiving antenna and the power transmitting antenna is within a predetermined range can be adopted.

[0513] However, since both ends of the power receiving antenna and a part of the power transmitting antenna are far away from each other, there is a possibility that the distance between the two parts is not within a predetermined range.

[0514] Fig.14 (C) shows an example in which the shape of the housing exterior near the power receiving antenna of RX is flat, the shape of the housing exterior near the power transmitting antenna of TX is flat, and the distance between the power receiving antenna and the housing exterior of RX is greater than or equal to a specified distance.

[0515] For example, in RX, there is a case where a component needs to be arranged on the lower side (TX side) of the power receiving antenna or the thickness of the outer shell needs to be sufficiently increased. When a predetermined area is required between the power receiving antenna and the outer shell of RX, the distance between the power receiving antenna and the power transmitting antenna (hereinafter referred to as the separation distance) increases. In addition, as a wireless charging system, the separation distance can be set to a specified distance or more.

[0516] Fig.14(D) shows an example in which there is a predetermined area between the power receiving antenna and the outer shell of RX and between the power transmitting antenna and the outer shell of TX. The shape of the outer shell near the power receiving antenna of RX is a plane, and the shape of the outer shell near the power transmitting antenna of TX is a plane. Fig.14 Compared with the separation distance in (C), Fig.14 The separation distance in (D) is larger, so the distance between the power receiving antenna and the power transmitting antenna is further increased.

[0517] Fig.14 (B) shows an example where the power transmitting antenna and the power receiving antenna are not directly facing each other, and Fig.14 (C) and (D) show examples where the separation distance between the antennas is greater than or equal to a predetermined distance. Even in this case, if wireless charging can be appropriately performed, the degree of freedom in designing the power transmitting device and the power receiving device can be increased.

[0518] exist Fig.14 In the example of (B), the coupling between the power transmitting antenna and the power receiving antenna is weaker, or the coupling coefficient between the power transmitting antenna and the power receiving antenna is smaller, compared with the case where the power transmitting antenna and the power receiving antenna face each other.

[0519] In addition, Fig.14 In the case of the examples of (C) and (D), the coupling between the power transmitting antenna and the power receiving antenna is weaker or the coupling coefficient between the power transmitting antenna and the power receiving antenna is smaller than when the separation distance of the antenna is less than the predetermined distance. In this embodiment, a method for enabling the power transmitting device to appropriately detect the placement of the power receiving device in a state where the coupling between the power transmitting antenna and the power receiving antenna is weak will be described.

[0520] In the above-mentioned selection phase (S1201 and S1301), TX intermittently transmits a simulated Ping. TX detects one or both of the voltage value and the current value of the power transmission antenna 105 when transmitting the simulated Ping, and detects that an object is placed on the charging base of TX.

[0521] In the Ping phase (S1201 and S1301), TX transmits a digital Ping, and RX notifies TX of a power receiving voltage value in response to the digital Ping. The power of the digital Ping is sufficient to activate the control unit of RX placed on TX.

[0522] By receiving the response from the RX that has received the digital Ping, the TX recognizes that the object detected in the selection phase is the RX. Here, the response received by the TX from the RX is a signal strength data packet. The packet has the power receiving voltage value of the digital Ping received by the RX as the signal strength value.

[0523] In traditional analog and digital Ping specifications, such as Fig.14 As shown in (A), the parameters are optimized so that TX detects RX when the antenna separation distance is within a predetermined range.

[0524] exist Fig.14 In the examples of (B), (C), and (D), since the coupling between the power receiving antenna and the power transmitting antenna is weak, there is a possibility that TX cannot detect the placement of RX using Ping. Fig.15 A configuration for enabling TX to detect placement of RX even if coupling between antennas is weak is described.

[0525] Fig.15 (A) and (B) are explanatory diagrams of analog Ping and digital Ping. Hereinafter, analog Ping is referred to as AP and digital Ping is referred to as DP.

[0526] Fig.15 (A) shows an example of a state in which the electromagnetic coupling between the power transmitting antenna and the power receiving antenna is stronger than that in a predetermined state (hereinafter also referred to as a strong coupling state). Fig.15 (B) shows an example of a state where the electromagnetic coupling between the power transmitting antenna and the power receiving antenna is weaker than the coupling in a predetermined state (hereinafter also referred to as a weak coupling state).

[0527] Fig.15 The horizontal axis in FIG. 1 is the time axis and the vertical axis represents the power of the AP and DP. Fig.15 In , Vinv represents a power transmission voltage applied to a circuit (for example, an inverter) provided in the TX power transmission unit 103. This is, for example, the inverter output voltage described above.

[0528] like Fig.15 As shown in (A) and (B), the TX transmission power of the AP changes periodically. For example, the power value is set to three levels: low level, medium level, and high level. Assume that "1" represents the minimum power, "3" represents the maximum power, and "2" represents the power between "1" and "3".

[0529] TX sequentially and periodically transmits APs of "1", "2", and "3". Hereinafter, APs of "1", "2", and "3" are represented by AP1, AP2, and AP3, respectively.

[0530] exist Fig.15 In the example of (A), as shown by the black arrow, it is assumed that RX is placed on TX at the timing between AP2 and AP3. For example, in a strong coupling state, the separation distance between the antennas is within a predetermined range.

[0531] In this state, if the power of AP1 is greater than or equal to the predetermined power (first power), TX can detect RX on TX. The first power is lower than the power of AP1. That is, in Fig.15 In (A), TX can detect RX through AP at all power levels (ie, low level, medium level, and high level).

[0532] like Fig.15 As shown in (A), after RX is placed on TX, RX is detected by AP3. Subsequently, RX is detected by AP1 and AP2. Furthermore, RX is detected again by AP3.

[0533] TX does not determine when RX is placed on the charging base 300. Therefore, TX determines whether the object (RX) can be detected twice by APs with the same power. When this condition is satisfied, after RX is placed on the charging base 300, TX can recognize that the attempt to detect the placement of RX using all APs with powers of "1" to "3" is completed.

[0534] exist Fig.15 In the example of (A), TX detects the object (RX) twice using AP3. Therefore, after the object (RX) is placed on the charging base 300, TX recognizes that the attempt to detect the placement of the object (RX) using APs of all power levels has been completed.

[0535] In the strong coupling state, after the detection attempt based on the APs with all power levels, TX recognizes that RX can be detected by each AP. In other words, TX recognizes that RX can be detected by APs above "1".

[0536] Next, in Fig.15 In the example of (B), as shown by the black arrow, it is assumed that RX is placed on TX at the timing between AP2 and AP3. For example, in the weak coupling state, Fig.14 As shown in (B), (C) and (D), the separation distance between the antennas is not within the predetermined range.

[0537] In this case, RX may not be detected by the AP that can detect RX in a strong coupling state. TX transmits AP from the power transmission antenna, and detects changes on the charging base 300 using changes in the acquired electrical physical quantity or the like.

[0538] In the weak coupling state, if the power of the AP is less than or equal to a predetermined threshold, there is a possibility that the TX cannot sufficiently detect the change in the electrical physical quantity. For example, when the RX on the TX is detected by the AP transmitted from the power transmitting antenna of the TX, the first state and the second state are assumed to be the coupling state between the power transmitting antenna and the power receiving antenna.

[0539] The strong coupling state is a state in which the coupling between the power transmitting antenna and the power receiving antenna is stronger than in the first state. The second state is a state in which the coupling between the power transmitting antenna and the power receiving antenna is weaker than in the first state.

[0540] When the coupling between the power transmitting antenna and the power receiving antenna is stronger than in the second state, an object (RX) can be detected by an AP having a predetermined power (second power) or more. Specifically, the second power is greater than the power of AP2 and less than the power of AP3. Fig.15 In the example of (B), TX can detect RX only through AP3 having the maximum power.

[0541] like Fig.15 As shown in (B), after RX is placed on TX, RX is detected by AP3. RX is not detected by AP1 and AP2. In addition, RX is detected again by AP3. When TX detects an object (RX) twice using APs with the same power, after RX is placed on the charging base 300, it can be recognized that the attempt to detect the placement of RX using APs of all power levels has been completed.

[0542] TX has detected the object (RX) twice using AP3. Therefore, after the object (RX) is placed on the charging base 300, TX recognizes that the attempt to detect the placement of the object (RX) using APs of all power levels has been completed. In the weak coupling state, after the detection attempts through APs of all power levels, TX recognizes that RX can only be detected through AP3 with the maximum power.

[0543] In this embodiment, an example is described in which multiple APs with different power levels are periodically transmitted. Fig.15 In the example of , a configuration in which AP3 with the largest power is continuously transmitted can also be thought of. In this configuration, because the transmission of the AP with the largest power is continuously performed, power consumption increases.

[0544] Therefore, TX transmits multiple APs with appropriate different power levels. Thus, even if the coupling between the power transmitting antenna and the power receiving antenna is stronger than in the first state, or even if the coupling between the power transmitting antenna and the power receiving antenna is stronger than in the second state, TX can detect that RX is placed. In addition, this detection process can be implemented more power-savingly.

[0545] Next, the DP transmitted after the detection of an object (RX) by the AP will be described. Fig.15 In the example of (A), after the placement of RX, TX attempts to detect the placement of the object using APs from AP1 to AP3. TX recognizes that the object can be detected by AP1, AP2, and AP3 (RX).

[0546] In the case of a strong coupling state, RX receives (receives power) a signal with higher power transmitted (sends power) from TX than in the case of a weak coupling state. The reason is that when the coupling state between the power transmitting antenna and the power receiving antenna is appropriate and the k value is large, the efficiency of power transmission from TX to RX is high. On the contrary, when the coupling state between the power transmitting antenna and the power receiving antenna is not appropriate and the k value is small, the efficiency of power transmission from TX to RX is low.

[0547] exist Fig.15 In the case of the strong coupling state shown in (A), since RX can be detected by AP1 with the minimum power, TX can recognize that the coupling between the power transmitting antenna and the power receiving antenna is strong. In this case, TX transmits DP with relatively low power from the power transmitting antenna. As a result, the control unit of RX placed on TX can be activated, and RX can transmit a response to DP (notification of the power receiving voltage value) to TX.

[0548] Thus, when RX can be detected with AP1 having minimum power, TX recognizes that the coupling between the power transmitting antenna and the power receiving antenna is stronger than in a predetermined state. TX transmits DP (A in the figure) having relatively low power.

[0549] This DP is called DPA. DPA corresponds to the case of "Vinv=VA". The RX placed on the TX receives the DPA and activates the control unit of the RX. In addition, the RX transmits a signal strength packet as a response to the DPA to the TX.

[0550] When TX receives the packet, it transitions to the I&C phase (S1202 and S1302). In the communication between TX and RX in the I&C phase, TX communicates with the power equal to the power in the case of transmitting DPA. Alternatively, in the communication between TX and RX in the I&C phase, TX communicates with Vinv (VA) equal to the voltage in the case of transmitting DPA.

[0551] On the other hand, Fig.15 In the case of the weak coupling state shown in (B), since RX can only be detected by AP3 with the maximum power, TX recognizes that the coupling between the power transmitting antenna and the power receiving antenna is weak. TX transmits DP with relatively high power from the power transmitting antenna. As a result, the control unit of RX placed on TX can be activated, and RX can transmit a response to DP (notification of the power receiving voltage value) to TX.

[0552] Therefore, when RX can be detected only by AP3 having the maximum power, TX recognizes that the coupling between the power transmitting antenna and the power receiving antenna is weaker than a predetermined state. TX transmits DP having relatively high power (B in the figure).

[0553] This DP is called DPB. This is the relationship of "power of DPB>power of DPA". DPB corresponds to the case of "Vinv=VB". There is a relationship of "VB>VA". The RX placed on the TX receives the DPB and activates the control unit of the RX.

[0554] In addition, RX transmits a signal strength data packet as a response to DPB. When TX receives the packet, it transitions to the I&C phase (S1202 and S1302).

[0555] In the communication between TX and RX in the I&C phase, TX communicates with power equal to that in the case of transmitting DPB. Alternatively, in the communication between TX and RX in the I&C phase, TX communicates with Vinv (VB) equal to the voltage in the case of transmitting DPB.

[0556] TX recognizes the coupling state between the power transmitting antenna and the power receiving antenna based on the AP with the smallest power among multiple APs that can detect the object (RX). Fig.15 In (A), the minimum power that can detect the object is the power of AP1, and the state is identified as a strong coupling state.

[0557] In addition, Fig.15 In (B), the minimum power that can be detected is the power of AP3, and the state is identified as a weak coupling state. TX changes the power of DP according to the identified coupling state. In other words, the power of DP is determined according to the minimum power of the AP that can detect the object.

[0558] Fig.16 is an illustrative sequence diagram of the operation of TX and RX. The operation of TX is shown on the left, and the operation of RX is shown on the right. In F1601, TX transmits AP. In F1602, RX is placed on the charging base 300. In F1603, TX transmits AP. In F1604, a placed object is detected. In F1605, TX transmits AP. In F1606, a placed object is detected.

[0559] In F1607, TX measures the Q value. In F1608, the DP corresponding to the AP that has detected the object is transmitted. In F1609, RX detects the placement on TX. In F1610, RX transmits a signal strength packet to TX.

[0560] In F1611, TX detects the placement of RX. In F1612, identification information and capability information are exchanged. TX obtains identification information and capability information from RX according to the communication in the I&C phase.

[0561] In F1613, TX determines the GP value with RX through communication in the negotiation phase. After executing the CAL process in F1614, TX starts the power transmission process in F1615.

[0562] Fig.17 17 is an explanatory flowchart of the operations of TX and RX. After the power of TX is turned on in S1701, TX transmits an AP that satisfies the initial condition for detecting whether an object has been placed on the charging base 300 in S1702.

[0563] For example, the initial condition is that the power of the AP is the minimum power. TX has a counter for counting the number of times the AP has been transmitted. In S1703, TX sets the value of the variable Count of the counter to 1.

[0564] In S1704, TX determines whether an object is detected by the transmitted AP. When an object has not been detected, the process proceeds to the process of S1705. TX waits for a predetermined time, and the process proceeds to the process of S1706. In addition, when an object has been detected, the process proceeds to the process of S1709.

[0565] In S1706, TX transmits an AP with a condition different from the condition of the AP transmitted last time. The condition different from the condition of the AP transmitted last time is that the power of the AP transmitted this time is higher than the power of the AP transmitted last time.

[0566] For example, when AP1 with the smallest power was transmitted last time, the power of the AP of this transmission is medium power (AP2). Next, in S1707, TX sets the value of the variable Count to a value increased by 1. Furthermore, the process proceeds to the process of S1708.

[0567] In S1708, TX determines whether an object is detected by the transmitted AP. When an object has been detected, the process proceeds to the process of S1709. When an object has not been detected, the process proceeds to the process of S1710. In S1710, TX waits for a predetermined time. In S1711, TX determines whether the value of the variable Count has reached a predetermined value.

[0568] For example, the predetermined value is 3. When the value of the variable Count has not reached the predetermined value 3, the process proceeds to the process of S1706. When the value of the variable Count is set to 2, the process proceeds to the process of S1706, and TX transmits an AP having a condition different from that of the AP of the previous transmission. Transmission of an AP different from AP2 of the previous transmission (i.e., AP3 having the maximum power) is performed.

[0569] On the other hand, when the value of the variable Count has reached the predetermined value 3, the process proceeds to the process of S1702. In this case, TX retransmits the AP that meets the initial condition. In other words, TX retransmits AP1 with the smallest power. As described above, TX performs control to periodically transmit a plurality of APs with different power levels.

[0570] In S1709, TX determines whether the object has been detected by APs under the same condition. The same condition is that the power levels of the multiple APs transmitted are the same. When the judgment condition of S1709 is met, the process proceeds to the process of S1712. When the judgment condition of S1709 is not met, the process proceeds to the process of S1710.

[0571] In S1712, TX measures the quality factor by the Q value measurement method. In addition, TX may detect whether the object is an object having a function of an NFC card or an RFID tag before or after the measurement of the quality factor by the Q value measurement method.

[0572] In this case, TX detects an object having a function of an NFC card or an RFID tag, and if it is determined that there is a possibility of damaging the object using the transmission power of TX, DP is not transmitted.

[0573] After TX stops transmission of the AP in the next S1713, TX transmits DPA or DPB according to the transmission condition of the AP that has detected the object in S1714. Furthermore, the process proceeds to the process of S1715.

[0574] In S1715, TX determines whether a signal strength data packet has been received from RX. When it is determined that a packet has been received, a series of processes ends. When it is determined that a packet has not been received, the process proceeds to the process of S1702.

[0575] In this embodiment, in the case where an object has not been detected in the previously transmitted AP, if an AP is also transmitted and the placement of an object (RX) is detected, the process proceeds to the process of S1709. When an object has been detected by an AP under the same condition, TX stops the transmission of the AP and transmits a DP corresponding to the condition of the AP that has detected the object.

[0576] At this time, TX determines the power of DP according to the power of AP that has detected the object. RX receives DP from TX and detects that RX has been placed on the charging base 300 of TX (F1609).

[0577] RX transmits a signal strength data packet to TX in response to DP (F1610). TX receives the packet and recognizes that RX has been placed on the charging base 300 (F1611).

[0578] The TX of this embodiment transmits while periodically changing the power of the AP used to detect the placement of the object in the order of low level, medium level, and high level. The present invention is not limited to this example. When an object has been detected by an AP, the TX can transmit an AP with a power lower than the power of the AP that detected the object as the next AP to be transmitted. In addition, the TX can also periodically transmit four or more types of APs with different power levels.

[0579] TX decides the power of DP according to the minimum power of AP that can detect the object. In other words, TX searches for the AP with the minimum power that can detect the object. The placement of the object can be detected in a shorter time. When the placement of the object is detected by the AP with the minimum power, the search can be ended at that point in time, the transmission of the AP can be stopped, and the power of DP can be decided and transmitted immediately.

[0580] In addition, in this embodiment, when the placement of the object is detected twice by APs under the same conditions (with the same power), it is determined that the attempt to detect the placement of the object by APs with three types of power has been completed. The present invention is not limited to this example. When TX recognizes that the detection of the placement of the object by APs with three types of power has been completed, it can be determined that the attempt to detect the placement of the object using all APs has been completed.

[0581] For example, TX detects the placement of an object once using AP3, and then tries to detect the placement of the object using AP1 and AP2. It can be determined that TX has tried to detect the placement of the object using all of AP1, AP2, and AP3.

[0582] As described above, in the first method, TX transmits a plurality of APs whose power changes periodically, and decides the power of the DP corresponding to the power of the AP having the minimum power capable of detecting an object.

[0583] Next, a second method of TX detecting placement of RX when coupling between the power transmitting antenna and the power receiving antenna is weak will be described. In the second method, TX makes the power levels of APs the same as each other and periodically changes the threshold used in the judgment when detecting placement of an object by APs.

[0584] The threshold value is a threshold value for a change in the voltage applied to the power transmission antenna or a change in the current flowing through the power transmission antenna. Alternatively, the threshold value is a threshold value for a change in the resonant frequency of the power transmission antenna or a change in the capacitance value of an electrode near the charging base 300 of the TX, wherein the change in the resonant frequency of the power transmission antenna can be calculated based on the change in the voltage applied to the power transmission antenna or the change in the current value flowing through the power transmission antenna.

[0585] Alternatively, the threshold is a threshold for a change in the value of a quality factor of a power transmission antenna or a circuit including the power transmission antenna. The change in the electrical physical quantity measured or calculated by the TX is caused by the placement of an object on the power transmission antenna. Therefore, when the change in the physical quantity is greater than or equal to a predetermined threshold, the TX can determine that the object has been placed on the power transmission antenna. Specifically, the reference Fig.18 A description is given of (A) and (B).

[0586] Fig.18 (A) shows the situation in the strong coupling state, and Fig.18 (B) shows the situation in the weak coupling state. The vertical and horizontal axes are set as Fig.15 TX sets the thresholds in the order of the first threshold, the second threshold, and the third threshold, and sequentially and periodically transmits APs with the same power. The first threshold is the maximum threshold, the third threshold is the minimum threshold, and the second threshold is a value between the first threshold and the third threshold.

[0587] exist Fig.18 In (A), as shown by the black arrow, after the transmission of the second AP, the RX is placed on the TX. Fig.14 As shown in (A), the separation distance between the antennas is within a predetermined range. Therefore, TX easily detects the change in physical quantity caused by the placement of RX. That is, in the case of a strong coupling state, the change in electrical physical quantity caused by the placement of RX on TX is greater than in the case of a weak coupling state.

[0588] When TX detects an object using AP, it is assumed that the coupling between the power transmitting antenna and the power receiving antenna is stronger than in the first state. In this case, when the change in the electrical physical quantity is greater than or equal to a predetermined value (first threshold), TX recognizes that an object has been placed (RX).

[0589] This indicates that “TX has detected RX with the first threshold.” Furthermore, it is assumed that the coupling between the power transmitting antenna and the power receiving antenna is weaker than in the first state and stronger than in the second state.

[0590] In this case, when the change in the electrical physical quantity is less than the first threshold value and greater than or equal to the second threshold value, TX recognizes that the object has been placed (RX). This indicates that "TX has detected RX using the second threshold value."

[0591] In addition, it is assumed that the coupling between the power transmitting antenna and the power receiving antenna is weaker than in the second state and stronger than in the third state. In this case, when the change in the electrical physical quantity is less than the second threshold and greater than or equal to the third threshold, TX recognizes that an object has been placed (RX). This indicates that "TX has detected RX using the third threshold."

[0592] exist Fig.18 In the embodiment, AP is periodically transmitted to judge whether an object has been placed in the order of a first threshold, a second threshold, and a third threshold. Then, DP of power corresponding to the judgment result is transmitted.

[0593] exist Fig.18 In the example of (A), as shown by the black arrow, after the RX is placed on the TX after the transmission of the second AP, the TX uses the third threshold to determine whether the object has been placed. Next, the TX detects the RX using the first threshold. Subsequently, the TX detects the RX using the first threshold again.

[0594] TX is not sure when RX is placed on the charging base 300. Assume that TX can detect the object (RX) twice using APs under the same conditions (with the same threshold). In this case, after RX is placed on the charging base 300, TX can recognize that the attempt to detect the placement of RX using all APs corresponding to the first to third thresholds has been completed.

[0595] exist Fig.18 In the example of (A), TX detects the object (RX) twice using the first threshold. Therefore, after the object (RX) is placed on the charging base 300, TX can recognize that the attempt to detect the placement of the object (RX) using the APs corresponding to all thresholds (the first threshold to the third threshold) has been completed. That is, TX recognizes that RX can be detected by the AP corresponding to the maximum threshold (the first threshold) when the change in the electrical physical quantity being measured or calculated is the maximum change.

[0596] exist Fig.18 In (B), as shown by the black arrow, after the transmission of the second AP, RX is placed on TX. Fig.14 As shown in (B), (C) and (D) of FIG. 1 , the separation distance between the antennas is not within the predetermined range. Therefore, RX may not be detected by the AP corresponding to the threshold at which RX can be detected in the case of a strong coupling state.

[0597] exist Fig.18 In the example of (B), after RX is placed on TX, TX detects RX using the third threshold. Thereafter, TX detects RX again using the third threshold. TX determines whether the object (RX) has been detected twice by the AP under the same condition (with the same threshold).

[0598] When this condition is satisfied, TX can recognize that the attempt to detect the placement of RX using APs corresponding to all thresholds (first to third thresholds) is completed after RX is placed on the charging base 300. TX detects the object (RX) twice using the AP corresponding to the third threshold.

[0599] Thus, after the object (RX) is placed on the charging base 300, TX can recognize that the attempt to detect the placement of the object (RX) using the APs corresponding to all thresholds has been completed. That is, TX recognizes that RX can only be detected by the AP corresponding to the third threshold when the change in the electrical physical quantity being measured or calculated is the minimum change.

[0600] Next, the DP according to the judgment result of the AP will be described. Fig.18 In the case of the strong coupling state shown in (A), since TX can easily detect the change in the physical quantity caused by the placement of RX, the change in the electrical physical quantity measured or calculated is a large value.

[0601] In this case, TX recognizes that RX can be detected by the AP corresponding to the maximum threshold value (first threshold value). In other words, TX can recognize that the coupling between the power transmitting antenna and the power receiving antenna is strong.

[0602] TX transmits DPA with relatively low power from the power transmission antenna. The control unit of RX placed on TX can be activated by this DPA, and RX can transmit a response to DP (notification of the power receiving voltage value) to TX.

[0603] Thus, when RX has been detected by the first threshold, TX recognizes that the coupling between the power transmitting antenna and the power receiving antenna is stronger than in the first state, and transmits DPA with low power. RX receives DPA and activates its control unit. In addition, RX transmits a signal strength data packet to TX.

[0604] When TX receives the packet, it transitions to the I&C phase (S1202 and S1302). In the communication between TX and RX in the I&C phase, TX communicates with the power equal to the power when DPA is transmitted. Alternatively, in the communication between TX and RX in the I&C phase, TX communicates with Vinv (VA) equal to the voltage in the case of transmitting DPA.

[0605] Next, in Fig.18 In the case of (B), since TX can detect RX using the third threshold, it is possible to identify a state in which the coupling between the power transmitting antenna and the power receiving antenna is weak. TX transmits DPB with relatively high power from the power transmitting antenna. The control unit of RX placed on TX can be activated according to DPB, and RX can transmit a response to DP (notification of the power receiving voltage value) to TX.

[0606] Thus, when RX is detected by the third threshold, TX recognizes that the coupling state between the power transmitting antenna and the power receiving antenna is weaker than in the second state and stronger than in the third state. TX transmits DPB with high power. RX receives DPB and activates its control unit.

[0607] In addition, RX transmits a signal strength data packet to TX. When TX receives the packet, it transitions to the I&C phase (S1202 and S1302). In the communication between TX and RX in the I&C phase, TX communicates with power equal to that when DPB is transmitted. Alternatively, in the communication between TX and RX in the I&C phase, TX communicates with Vinv (VB) equal to the voltage in the case of DPB transmission.

[0608] In the second method, TX identifies the coupling state between the power transmitting antenna and the power receiving antenna based on the threshold set for the AP for detecting the object (RX). TX determines the power of DP according to the threshold of the AP that can detect the object (RX) (determines the power according to the coupling state).

[0609] Will refer to Fig.16 and Fig.17 The operations of TX and RX in the second method will be described. In addition, only the differences from the first method will be described. Fig.16 In F1601, TX transmits an AP corresponding to a first threshold. In F1603, TX transmits an AP corresponding to a second threshold. In F1605, TX transmits an AP corresponding to a third threshold. TX identifies the coupling state between the power transmitting antenna and the power receiving antenna, and determines the power of DP according to the coupling state.

[0610] exist Fig.17 In S1702, TX transmits an AP that meets the initial condition. The initial condition is that the judgment threshold is a first threshold. In S1706, TX transmits an AP under a condition different from the condition of the AP transmitted last time.

[0611] The condition is that the judgment threshold is the second threshold. Alternatively, when the AP of the previous transmission corresponds to the second threshold, the condition is that the judgment threshold is the third threshold. TX periodically transmits APs with the same power corresponding to each of the first to third thresholds.

[0612] When Fig.17 When the placement of the object (RX) is detected in S1704 or S1708, in S1709, TX determines whether the object has been detected by the AP under the same condition. The same condition is that the thresholds corresponding to the APs have the same value.

[0613] When the object has been detected by the AP under the same condition, TX performs the processing of S1712 to S1714. In S1714, TX transmits a DP corresponding to the condition of the AP that detected the object. TX decides the power of the DP according to the judgment threshold set for the AP.

[0614] Next, a third method of TX detecting the placement of RX when the coupling between the power transmitting antenna and the power receiving antenna is weak will be described. TX transmits multiple APs with the same power. In the case where TX has detected a change in the measured or calculated electrical physical quantity when the AP is transmitting, TX determines the power of DP according to the change in the detected physical quantity. Specifically, reference will be made to Fig.19 A description is given of (A) and (B).

[0615] Will refer to Fig.19 (A) describes the case of a strong coupling state. As shown by the black arrow, it is assumed that after the transmission of the second AP, the RX is placed on the TX. Fig.14 As shown in (A), it is assumed that the separation distance between the antennas is within a predetermined range. In the case of a strong coupling state, the change in the electrical physical quantity caused by the placement of the RX on the TX is larger than that in the case of a weak coupling state.

[0616] The change in the electrical physical quantity is a change in the voltage applied to the power transmission antenna or a change in the current flowing through the power transmission antenna. Alternatively, the change is a change in the resonant frequency of the power transmission antenna or a change in the capacitance value of the electrode near the charging base 300 of the TX, wherein the change in the resonant frequency of the power transmission antenna can be calculated based on the change in the voltage applied to the power transmission antenna or the change in the current value flowing through the power transmission antenna.

[0617] Alternatively, the change is a change in the value of the quality factor of the power transmitting antenna or a circuit including the power transmitting antenna. Three types of thresholds are set for the change in the electrical physical quantity measured or calculated by the TX. When the coupling between the power transmitting antenna and the power receiving antenna is stronger than in the first state, it is assumed that the change in the electrical physical quantity is greater than or equal to the first threshold.

[0618] This indicates that “TX has detected RX with the first threshold.” Furthermore, it is assumed that when the coupling between the power transmitting antenna and the power receiving antenna is weaker than in the first state and stronger than in the second state, the change in the electrical physical quantity is less than the first threshold and greater than or equal to the second threshold.

[0619] This indicates that "TX has detected RX with the second threshold value". In addition, it is assumed that when the coupling between the power transmitting antenna and the power receiving antenna is weaker than in the second state and stronger than in the third state, the change in the electrical physical quantity is less than the second threshold value and greater than or equal to the third threshold value. This indicates that "TX has detected RX with the third threshold value".

[0620] exist Fig.19In (A), as indicated by the black arrow, after the object (RX) is placed on the TX, a judgment process is performed to judge whether there is a change in the electrical physical quantity measured or calculated by the TX based on the AP.

[0621] TX determines that the change in the electric physical quantity is within the range based on the first threshold value. TX recognizes that the coupling between the power transmitting antenna and the power receiving antenna is stronger than in the first state.

[0622] Will refer to Fig.19 (B) describes the case of a weak coupling state. As indicated by the black arrow, after the object (RX) is placed on the TX, a judgment process is performed based on the AP to judge whether there is a change in the electrical physical quantity measured or calculated by the TX.

[0623] In this case, if Fig.14 As shown in (B), (C) and (D) of FIG. 1 , the separation distance of the antenna is not within the predetermined range. TX determines that the change in the electrical physical quantity is within the range based on the third threshold. TX recognizes that the coupling between the power transmitting antenna and the power receiving antenna is weaker than in the second state and stronger than in the third state.

[0624] In the third method, TX transmits AP and detects a change in the measured or calculated electrical physical quantity based on AP. In this case, TX determines whether the object (RX) has been placed on the charging base 300.

[0625] TX compares the change in the electrical physical quantity measured or calculated at that time with the threshold value, and performs processing to determine the range of the change determined by the first threshold value, the second threshold value, and the third threshold value.

[0626] Next, the DP transmitted by the TX after an object is detected by the AP (RX) will be described. Fig.19 In the case of (A), TX detects RX using the first threshold value and recognizes that the change in the electrical physical quantity is the maximum change.

[0627] In the strong coupling state, TX transmits a relatively low-power DPA from the power transmission antenna. The control unit of RX placed on TX can be activated according to DPA, and RX can transmit a response to DP (notification of the power receiving voltage value) to TX.

[0628] Thus, if the change of the electrical physical quantity measured or calculated by the TX is within the range based on the first threshold, the TX transmits the DPA with low power. The RX placed on the TX activates the control unit and transmits a signal strength data packet to the TX.

[0629] When TX receives a packet from RX, it transitions to the I&C phase (S1202 and S1302). In the communication between TX and RX in the I&C phase, TX communicates with the power equal to the power when DPA is transmitted. Alternatively, in the communication between TX and RX in the I&C phase, TX communicates with Vinv (VA) equal to the voltage in the case of transmitting DPA.

[0630] exist Fig.19 In the case of (B), TX detects RX using the third threshold. In the weak coupling state, TX transmits DPB with relatively high power from the power transmission antenna. The control unit of RX placed on TX can be activated according to DPB, and RX can transmit a response to DP (notification of the power receiving voltage value) to TX.

[0631] Thus, when the change in the electrical physical quantity measured or calculated by TX is within the range based on the third threshold, TX transmits a DPB with high power. The RX placed on TX activates the control unit and transmits a signal strength data packet to TX. When TX receives the packet from RX, it transitions to the I&C stage (S1202 and S1302).

[0632] In the communication between TX and RX in the I&C phase, TX communicates with power equal to that when DPB is transmitted. Alternatively, in the communication between TX and RX in the I&C phase, TX communicates with Vinv (VB) equal to the voltage when DPB is transmitted.

[0633] In the third method, TX identifies the coupling state between the power transmitting antenna and the power receiving antenna according to the change of the electrical physical quantity to be measured or calculated, and changes the power of DP according to the coupling state. In other words, the power of DP is determined according to the change of the electrical physical quantity when TX has transmitted AP.

[0634] Will refer to Fig. 20 and Fig.21 Describes the operation of TX and RX. Fig. 20 In F2001, TX transmits AP. In F2002, RX is placed on TX. In F2003, TX transmits AP. In F2004, the placement of the object is detected.

[0635] In F2005, TX measures the Q value. In F2006, TX transmits DP with power determined according to the change in the electrical physical quantity when TX has transmitted AP. In the following, because the operations from F2007 to F2013 are the same as Fig.16 The operations from F1609 to F1615 are similar, so their description will be omitted.

[0636] exist Fig.21In S2101, the power of TX is turned on, and in S2102, TX transmits AP. Next, in S2103, TX determines whether the object has been placed on the charging base 300.

[0637] A process is performed to determine whether there is a predetermined change in the electrical physical quantity measured or calculated by the TX based on the AP. When placement of an object is detected, the process proceeds to the process of S2105. When placement of an object has not been detected, the process proceeds to the process of S2104.

[0638] In S2104, TX waits for a predetermined time, the process proceeds to the process of S2102 and retransmits AP. When placement of an object has been detected by AP, the process proceeds to the process from S2103 to S2105.

[0639] In S2105, TX identifies the threshold range in which the measured or calculated electrical physical quantity has a change. In this embodiment, the process of determining the range in which the change of the electrical physical quantity exists is performed based on the first threshold to the third threshold. The process from S2106 to S2109 is the same as Fig.17 The processing from S1712 to S1715 is similar.

[0640] However, in S2108, TX determines the power of DP according to the threshold range (based on the range of the first threshold to the third threshold) in which the measured or calculated electrical physical quantity varies, and controls to transmit DP with power that varies according to the coupling state between the power transmitting antenna and the power receiving antenna.

[0641] Next, a fourth method of placing TX to detect RX when coupling between the power transmitting antenna and the power receiving antenna is weak will be described. In the first and second methods, an example of periodically changing the magnitude of the power of the AP and the control of the threshold for detecting the presence of an object has been described.

[0642] In the third method, an example of DP specific power control corresponding to the change of the electrical physical quantity measured or calculated by TX when transmitting AP has been described. In either method, a process of initially detecting placement of an object (RX) on TX using AP is performed.

[0643] In contrast to these methods, in the fourth method, a configuration and control in which placement of an object (RX) on TX can be detected through DP when placement of an object (RX) on TX cannot be detected through AP will be described.

[0644] Fig. 22 (A) to (C) are diagrams for explaining signals for detecting placement of an object (RX) on TX. The vertical and horizontal axes are arranged in the same way as Fig.15 The same as in. Fig. 22(A) shows the case where RX is not placed on TX. Fig. 22 (B) and (C) show the case where RX is placed on TX. Fig. 22 (B) shows the case of a strong coupling state, and Fig. 22 (C) shows the case of a weak coupling state.

[0645] exist Fig. 22 In (A), RX is not placed on TX, and DP is transmitted regardless of whether the placement of the object (RX) is detected by AP. When RX has received DP from TX, it transmits a signal strength packet to TX as a response thereto.

[0646] TX receives the packet. That is, the DP transmitted by TX has a function that can detect that RX has been placed. When the object (RX) has not been detected, it can be detected that RX has been placed on TX by performing transmission of AP and transmission of DP at predetermined intervals as a signal for detecting the object (RX).

[0647] Because AP is a signal for detecting the placement of an object on TX, the power is low. On the other hand, DP has enough power to activate the control unit of RX, which is higher than the power of AP. Therefore, when the coupling between the power transmitting antenna and the power receiving antenna is weak, even if the placement of RX on TX cannot be detected by AP, there is a possibility that it can be detected using DP.

[0648] When RX is placed on TX and the coupling between the power transmitting antenna and the power receiving antenna is weak, TX transmits AP and DP at a predetermined interval. Even if RX cannot be detected by AP, if RX can be detected by DP, the probability of detecting RX increases.

[0649] exist Fig. 22 In the example of (A), TX transmits AP twice and transmits DP once. This transmission is performed periodically. At this time, TX periodically changes the power of DP. The reason is similar to the reason for changing the power of AP and transmitting AP in the first method.

[0650] That is, this is because when placement of an object (RX) on TX cannot be detected by AP, placement of RX on TX can be detected by DP regardless of whether the coupling state is strong or weak. Examples of three types of DPA, DPB, and DPC are shown.

[0651] ·DPA: This is the minimum power (see Fig. 22 It corresponds to the case where (A)) and “Vinv=VA”.

[0652] ·DPB: This is related to the power supply for medium power (see Fig. 22It corresponds to the case where (B)) and "Vinv=VB".

[0653] DPC: This is the maximum power (see Fig. 22 This corresponds to the case where (C) and “Vinv=VC”.

[0654] This is the relationship of “power of DPC>power of DPB>power of DPA.” In addition, this is the relationship of “VC>VB>VA,” and TX periodically performs transmission in the order of DPA, DPB, and DPC.

[0655] Next, we will describe Fig. 22 Example of (B). Although this state is a strongly coupled state, it is assumed that TX cannot detect the placement of RX through AP. TX transmits DPA after transmitting a predetermined number of APs (2 APs). RX activates the control unit using DPA and recognizes that DPA has been received.

[0656] In addition, RX transmits a signal strength data packet in response to DPA. TX recognizes that RX has been placed by receiving the packet from RX. In other words, TX recognizes that the placement of RX has been detected using DPA with minimum power. TX retransmits AP a predetermined number of times and then transmits DPB.

[0657] RX activates the control unit using DPB and recognizes that DPB has been received. In addition, RX transmits a signal strength data packet in response to DPB. TX recognizes that RX has been placed by receiving the packet from RX. In other words, TX recognizes that the placement of RX has been detected by DPB. Subsequently, TX recognizes that the placement of RX has been detected by DPC according to a similar process.

[0658] like Fig. 22 As shown in (B), TX detects RX using DPA, DPB, and DPC. In addition, TX detects RX again using DPA. When TX has detected the object (RX) twice using DP under the same conditions, it can be recognized that after RX is placed on the charging base 300, all attempts to detect the placement of RX using DPA, DPB, and DPC have been completed.

[0659] For example, TX detects the object (RX) twice using DPA, and recognizes that the attempt to detect the placement of the object (RX) using all DPs has been completed after the object (RX) is placed on the charging base 300. Based on the attempt based on DP, TX recognizes that after the placement of RX, RX can be detected by all DPs. In other words, TX recognizes that the placement of RX can be detected using DPA with minimal power.

[0660] Next, we will describe Fig. 22Example of (C). Assume that the state is a weak coupling state, and TX cannot detect the placement of RX using AP. After TX transmits AP a predetermined number of times, TX transmits DPC to detect an object (RX). In addition, TX does not use DPA and DPB to detect an object (RX). TX retransmits DPC to detect an object (RX).

[0661] Detecting the object (RX) by two DPC Pings allows TX to recognize that the attempt to detect the placement of the object (RX) using all DPs is complete after the object (RX) is placed on the charging base 300. In this case, TX recognizes that RX can only be detected by the DPC with the maximum power.

[0662] Next, the DP transmitted by TX after the placement of an object (RX) is detected by DP will be described. Fig. 22 In the case of (B), TX tries to detect the placement of the object using all DPs, and recognizes that the placement of RX can be detected by all of DPA, DPB, and DPC. Since the placement of RX can be detected by DPA with the minimum power, TX can recognize that the coupling between the power transmitting antenna and the power receiving antenna is strong.

[0663] Therefore, TX transmits DP with relatively low power from the power transmission antenna. In other words, TX then transmits DPA with minimum power. The control unit of RX placed on TX can be activated by DPA, and RX can transmit a response to DPA (notification of the power receiving voltage value) to TX.

[0664] When RX transmits a signal strength data packet and TX receives the packet, it transitions to the I&C phase (S1202 and S1302). In the communication between TX and RX in the I&C phase, TX communicates with power equal to that in the case of transmitting DPA. Alternatively, in the communication between TX and RX in the I&C phase, TX communicates with Vinv (VA) equal to that in the case of transmitting DPA.

[0665] exist Fig. 22 In the case of (C), since TX can detect the placement of RX using only DPC, TX can recognize that the coupling between the power transmitting antenna and the power receiving antenna is weak. Therefore, TX transmits DP with relatively high power from the power transmitting antenna.

[0666] In other words, then, TX transmits DPC with maximum power. The control unit of RX placed on TX can be activated by DPC, and RX can transmit a response to DPC (notification of power receiving voltage value) to TX.

[0667] When RX transmits a signal strength data packet and TX receives the packet, it transitions to the I&C phase (S1202 and S1302). In the communication between TX and RX in the I&C phase, TX communicates with power equal to that in the case of transmitting DPC. Alternatively, in the communication between TX and RX in the I&C phase, TX communicates with Vinv (VC) equal to the voltage in the case of transmitting DPC.

[0668] In the fourth method, TX identifies the coupling state between the power transmitting antenna and the power receiving antenna according to the power value of the DP with the minimum power among the multiple DPs that can detect the placement of the object (RX). TX changes the power of the DP transmitted after detecting the placement of RX on TX according to the coupling state. In other words, the power of the DP is determined according to the minimum power that can detect the placement of RX.

[0669] exist Fig. 22 In the example of , a configuration in which TX continuously transmits DPC with maximum power is also conceivable. In this configuration, because TX continuously transmits DP with maximum power, power consumption increases.

[0670] Furthermore, even if the coupling state between the power transmitting antenna and the power receiving antenna is stronger than in the first state, the DPC is used to shift to the I&C phase. As a result of supplying more power than necessary to the RX according to the DP, the RX may be damaged.

[0671] TX can detect that RX is placed on TX by transmitting multiple DPs with different power levels. Even if the coupling state between the power transmitting antenna and the power receiving antenna is stronger than in the first state, or even if the coupling state is stronger than in the second state, TX can detect that RX has been placed. In addition, this detection process can be implemented more power-savingly, and transition to the I&C stage is made with DPs with appropriate power.

[0672] Will refer to Figure 23 to Figure 25 Describes the detailed operation of TX and RX. Fig.23 , TX transmits AP in F2301 and F2302, and transmits DP with the first power in F2303. TX transmits AP in F2304 and F2305, and transmits DP with the second power in F2306.

[0673] TX transmits AP in F2307 and F2308, and transmits DP with the third power in F2309. TX transmits AP in F2310 and F2311, and transmits DP with the first power in F2312.

[0674] In F2313, RX is placed on TX. TX transmits AP in F2314 and F2315, and transmits DP in F2316. RX detects placement on TX in F2317, and transmits a signal strength packet to TX in F2318.

[0675] Because TX receives the packet in F2319, the placement of RX is detected. In F2320 to F2328, as described above, two AP transmissions and one DP transmission are periodically performed.

[0676] RX detects the placement on TX in F2329 and transmits a signal strength packet to TX in F2330. Because TX receives the packet in F2331, the Q value is measured in F2332 after detecting the placement of RX.

[0677] In F2333, TX transmits DP. In the following, because the operation from F2334 to F2340 is the same as Fig.16 The operations from F1609 to F1615 are similar, so their description will be omitted.

[0678] exist Fig.24 In S2401, the power of TX is turned on. TX has a function of counting the number of AP transmissions, and the variable of the first counter is represented by Counter_A. In S2402, TX sets the value of Counter_A to zero.

[0679] In addition, TX has a function of counting the number of DP transmissions, and a variable of the second counter is represented by Counter_B. In S2403, TX sets the value of Counter_B to zero.

[0680] In S2404, TX transmits AP to detect that the object has been placed on the charging base 300. Subsequently, in S2405, TX increases (increments) the value of Counter_A by 1.

[0681] Furthermore, in S2406, TX determines whether an object (RX) has been detected by the AP transmitted in S2404. When an object (RX) has been detected, the process proceeds to the process of S2417. When an object (RX) has not been detected, the process proceeds to Fig.25 Processing of S2407 in.

[0682] In S2407, TX waits for a predetermined time corresponding to the transmission interval of the AP or the transmission interval of the AP and the DP. In S2408, TX determines whether the value of Counter_A has reached a predetermined number of times (eg, 2).

[0683] When it is determined that the value of Counter_A has reached the predetermined number of times, the process proceeds to the process of S2409. When it is determined that the value of Counter_A has not reached the predetermined number of times, the process proceeds to the process of S2404.

[0684] For example, when the value of Counter_A is 1 (No in S2408), TX transmits AP in S2404, and increases the value of Counter_A by 1 and sets it to 2 in S2405. When an object has not been detected in S2406 (No in S2406), after waiting in S2407, it is determined in S2408 that Counter_A has reached 2, which is a predetermined number of times (Yes in S2408).

[0685] In S2409, TX determines whether the value of Counter_B has reached a predetermined number of times (for example, 3). When it is determined that the value of Counter_B has reached the predetermined number of times, the process proceeds to S2414. When it is determined that the value of Counter_B has not reached the predetermined number of times, the process proceeds to S2410.

[0686] In S2410, TX changes to a condition different from the condition in the case of transmitting the previous digital Ping, and transmits the DP after the change. In this regard, when DP is transmitted for the first time after TX is activated, DP of the initial condition is transmitted.

[0687] The initial condition is that the power of DP is the minimum power ( Fig. 22 Subsequently, in S2411, TX increases the value of Counter_B by 1, and then proceeds to the process of S2412.

[0688] In S2412, TX determines whether RX has been detected through the transmitted DP. When TX transmits DP to RX and receives a signal strength packet from RX, it is determined that RX has been detected, and the process proceeds to the process of S2416.

[0689] Furthermore, when TX does not receive a signal strength packet from RX, it is determined that RX has not been detected, and the process proceeds to S2413. Since AP is transmitted a predetermined number of times in S2413, TX sets the value of Counter_A to zero, and then proceeds to S2404.

[0690] TX repeats the processing of S2404 to S2408 again. For example, when AP has been transmitted twice ("Yes" in S2408), TX determines in S2409 whether the value of Counter_B has reached a predetermined number of times.

[0691] When the value of Counter_B is 1 (No in S2409), the process proceeds to S2410, and TX transmits a DP with conditions different from those of the previous DP transmission (F2305). When the power of the previous DP is the minimum power, in S2410, the DPB with the next highest power is transmitted as the current DP.

[0692] In S2411 , Counter_B is incremented, and the value of Counter_B is set to 2. When RX has not been detected in S2412 , the value of Counter_A is set to zero in S2413 , and then the processing from S2404 to S2408 is repeated again.

[0693] When the value of Counter_B has not reached 3, which is the predetermined number of times, a DP with conditions different from those of the previous DP transmission is transmitted in S2410. When the previous DP is DPB, DPC is transmitted as this DP.

[0694] In S2411 , the value of Counter_B is incremented by 1 and set to 3. When RX has not been detected in S2412 , the process proceeds to the processes of S2413 and S2404 , and the processes from S2404 to S2408 are repeated again.

[0695] In this case, since the value of Counter_B is 3 as the predetermined number of times ("Yes" in S2409), the process proceeds to the process of S2414. In S2414, TX transmits the DP of the initial condition (F2312). The DPA with the minimum power is transmitted. Subsequently, in S2415, TX sets the value of Counter_B to zero. In addition, the process proceeds to the process of S2412.

[0696] According to the above control, TX periodically transmits AP and DP. After RX is placed on TX, TX performs the above control and transmits DP to detect RX ("Yes" in S2412), and the process proceeds to the process of S2416.

[0697] In S2416, TX determines whether RX has been detected through DP under the same condition. When RX has not been detected previously through DP under the same condition ("No" in S2416), the process proceeds to the process of S2404 via S2413. In this case, AP and DP are transmitted periodically.

[0698] Furthermore, when RX has been previously detected by DP under the same condition ("YES" in S2416), the process proceeds to S2417 ( Fig.24In addition, when TX has detected the object (RX) twice using DP under the same condition, it can be recognized that the attempt to detect the placement of RX on the charging base 300 using all DPs (DPA, DPB, and DPC) has been completed.

[0699] In S2417, TX measures the quality factor by a Q value measurement method. In addition, TX may detect whether the object is an object having a function of an NFC card or an RFID tag before and after the measurement.

[0700] When TX detects an object having such a function and determines that the power transmitted by TX may cause damage, DP is not transmitted. After S2417, the process proceeds to the process of S2418.

[0701] In S2418, TX transmits DP corresponding to the condition of Ping when an object has been detected. Specifically, when an object has been detected by AP, control is performed to transmit DP of the initial condition (minimum power). In addition, when an object has been detected by DP (RX), control is performed to transmit DP of power corresponding to the condition of DP.

[0702] TX determines the power of the DP to be subsequently transmitted according to the power of the DP of the minimum power of the detected object. TX transmits the DP of the determined power, and RX receives the DP from TX and detects placement on the charging base 300 (F2334). RX transmits a signal strength data packet as a response to the DP to TX (F2335). After S2418, the process proceeds to the process of S2419.

[0703] In S2419, TX determines whether a signal strength packet has been received from RX. When the determination condition is met, TX recognizes that RX has been placed (F2336).

[0704] A series of processes are completed, and the phase transitions to the I&C phase (S1202 and S1302). In the communication between TX and RX in the I&C phase, TX communicates with power equal to that of the DP to be transmitted in S2418.

[0705] Alternatively, in the communication between TX and RX in the I&C phase, TX communicates using Vinv equal to the voltage of DP transmitted in S2418. When TX does not receive the signal strength packet (No in S2419), the process proceeds to the process of S2413 (or S2402).

[0706] In the above example, control is performed to transmit three types of DPs with different power levels in the order of low, medium, and high power levels, but the present invention is not limited to this example. For example, when TX detects RX using DP, a DP with lower power than the DP that has detected RX can be transmitted as the next DP.

[0707] As described above, TX decides the power of DP in the I&C phase according to the power of DP with minimum power that can detect RX. That is, since the purpose is to search for DP with minimum power that can detect RX, TX can detect the placement of RX in a shorter time according to the above method.

[0708] In addition, after detecting the placement of RX through DPA with minimum power, TX does not transmit DPB or DPC. That is, TX can immediately decide the power of DP and transmit DP in the I&C stage.

[0709] In addition, in the above example, when the placement of the object has been detected twice using DP under the same conditions (with the same power), TX determines that the attempt to detect the placement of the object using all DPs of low, medium, and high power levels has been completed. The present invention is not limited to this example. TX can recognize that the attempt to detect the placement of the object using all DPs of low, medium, and high power levels has been completed.

[0710] For example, in Fig. 22 In (B), TX detects the placement of the object twice using DPA and determines that the placement of the object has been attempted using all DPs. Instead of this judgment, TX detects the placement of the object once using DPA and then detects the placement of the object using DPB and DPC, so that it can be determined that the attempt to detect the placement of the object using all DPs has been completed.

[0711] Next, another method for TX to detect the placement of RX when the coupling between the power transmitting antenna and the power receiving antenna is weak will be described. In the first to fourth methods described above, TX transmits DP to RX before transitioning to the I&C phase. RX having received DP transmits a signal strength packet as a response to DP to TX.

[0712] The signal strength packet stores the voltage value of DP received by RX as the signal strength value. When TX receives the signal strength packet from RX, the power or Vinv of DP may change with the signal strength value.

[0713] For example, TX compares the signal strength value with a predetermined threshold value. When the signal strength value is less than the predetermined threshold value, TX controls so that the power or Vinv increases by the difference between the two values ​​and transmits DP.

[0714] In addition, when the signal strength value is greater than a predetermined threshold value, TX controls so that the power or Vinv is reduced by the difference between the two values ​​and transmits DP. In the communication between TX and RX in the I&C phase, TX communicates with the power (or Vinv) equal to the power (or Vinv) of DP that changes according to the signal strength value.

[0715] The above method is also applicable to the DP for detecting the placement of RX described in the fourth method. Fig. 22 As shown, although TX periodically changes the power of DP and transmits DP, when the control unit 201 of RX has been activated, RX can transmit the signal strength data packet to TX.

[0716] Therefore, TX can change the power or Vinv of the DP to be transmitted subsequently according to the signal strength value.

[0717] Alternatively, as another method, TX or RX can calculate (measure) the coupling state index between the power transmitting antenna and the power receiving antenna, and determine the power or Vinv of DP based on the calculation (measurement) result. TX or RX calculates (measures) the coupling state index based on the first measurement method or the second measurement method described above.

[0718] According to the calculated (measured) coupling state index, the power or Vinv of DP can be changed. For example, TX compares the calculated coupling state index with a predetermined threshold. Here, the setting method of the state judgment threshold for the coupling state index obtained by the first measurement method or the second measurement method described above can be applied to set the predetermined threshold.

[0719] When the value of the coupling status indicator is smaller than (or larger than) a predetermined threshold, TX controls such that the power or Vinv increases (or decreases) by the difference between the two values ​​and transmits DP with the increased (decreased) power or Vinv.

[0720] In the communication between TX and RX in the I&C phase, TX communicates with power equal to power of DP changed according to the coupling state indicator. Alternatively, in the communication between TX and RX in the I&C phase, TX communicates with Vinv equal to Vinv of DP changed according to the coupling state indicator.

[0721] Furthermore, in the first method to the fourth method, it is assumed that TX transmits DP to RX before transitioning to the I&C phase. At this time, it is assumed that RX cannot receive DP (the control unit 201 of RX cannot be activated).

[0722] The signal strength packet is not transmitted from RX to TX. Alternatively, the signal strength packet is transmitted from RX to TX, but TX may not receive the signal strength packet.

[0723] In this case, after waiting for a predetermined time, TX controls to transmit a DP having higher power than the previously transmitted DP to RX. Alternatively, TX controls to transmit a DP having higher Vinv than the previously transmitted DP to RX. Thereafter, a state in which RX cannot receive the DP or TX cannot receive the signal strength packet may continue.

[0724] In this case, TX also performs control for transmitting DP with higher power. Alternatively, TX also performs control for transmitting DP with higher Vinv. In this way, if the above state continues before transitioning to the I&C phase, TX appropriately controls the power or Vinv of the DP to be transmitted to RX.

[0725] In other words, TX sets the power or Vinv of DP to be transmitted initially to the minimum power, increases the power or Vinv in stages, and performs DP transmission a plurality of times. It is assumed that the number of stages for changing the power or Vinv is two or more.

[0726] When TX has received a signal strength packet from RX, it transitions to the I&C phase using power of DP, power determined based on Vinv, or DP of Vinv.

[0727] In the communication between TX and RX in the I&C phase, TX communicates with power equal to the power of the decided DP. Alternatively, in the communication between TX and RX in the I&C phase, TX communicates with Vinv equal to the voltage of the decided DP.

[0728] Even if TX does not change its power and does not change the judgment threshold, the above method is applicable to AP transmitted by TX before transitioning to the I&C phase. In addition, even if TX does not change its power, the above method is applicable to DP transmitted by TX before transitioning to the I&C phase.

[0729] In other words, the above method is applicable regardless of the condition of the AP or DP transmitted by the TX before the transition to the I&C phase. In this way, when transitioning to the I&C phase, the probability of power transmission from the TX to the RX increases.

[0730] As described above, in this embodiment, the power of the AP or DP to be transmitted to detect the placement of an object on the TX or the judgment reference value (threshold) for detecting the placement is controlled. With this control, even if the coupling between the power transmitting antenna and the power receiving antenna is weak, it is possible to detect that an object has been placed on the TX.

[0731] In addition, by controlling the judgment reference value for detecting the placement of an object on TX, the placement of multiple objects (RX) having different electrical characteristics can be detected. Here, the "electrical characteristics" are, for example, the power (start-up power) of the control unit 201 that can activate RX or the maximum power that can be supplied to RX.

[0732] When a plurality of RXs having different electrical characteristics are placed on the TX, the TX can detect and identify the plurality of RXs. In addition, the above methods described in this embodiment can be appropriately combined and performed.

[0733] According to the present embodiment, even if the electromagnetic coupling between the power transmitting antenna and the power receiving antenna is weak, the process of detecting the placement of the object can be performed more appropriately.

[0734] [Second embodiment]

[0735] Will refer to Figure 26 to Figure 29 A second embodiment is described. In this embodiment, a method of recognizing that a power transmitting device and a power receiving device are in a weak coupling state will be described. In addition, a method of recognizing that a power transmitting device and a power receiving device are in a strong coupling state will be described.

[0736] For example, there are Fig.14 In the case where the power transmitting antenna and the power receiving antenna are not facing each other as shown in (B), or Fig.14 (C) and (D) show the case where the separation distance between the antennas is greater than or equal to the predetermined distance.

[0737] Alternatively, even if the spacing distance between the antennas is less than the predetermined distance, a conductor, dielectric, magnetic material, etc. may exist near the power transmitting antenna or the power receiving antenna. Depending on the presence of the conductor, dielectric, magnetic material, etc., there is a possibility that the coupling between the power transmitting antenna and the power receiving antenna will be weak.

[0738] In the third embodiment, a specific control performed in the case of a weak coupling state will be described. In this embodiment, a method for identifying a weak coupling state will be described. It is necessary to correctly identify that TX and RX are in a weak coupling state so that TX and RX perform predetermined control in the case of a weak coupling state. In this embodiment, matters similar to those in the first embodiment will not be described, and only the differences will be described. This method of omitting description is also applicable to the embodiments to be described below.

[0739] First, a first method for the power transmitting device and the power receiving device to recognize that the state is a weak coupling state will be described. Fig.14 In the examples of (B), (C), and (D), when RX has been placed on TX, there is a possibility that a weak coupling state may occur, and it is assumed that the powered device has known this.

[0740] Alternatively, near the power receiving antenna, there may be a conductor, dielectric, or magnetic material that constitutes a part of the housing of the RX. Due to the presence of the conductor, dielectric, or magnetic material, there is a possibility of a weak coupling state, and it is assumed that the power receiving device is aware of this. The RX can notify the TX of predetermined information indicating the possibility of the weak coupling state.

[0741] Alternatively, RX may notify TX of predetermined information indicating that the structure near the power receiving antenna of RX satisfies a predetermined condition. Here, the predetermined condition refers to a case where the distance between the outside of the housing of RX and the power receiving antenna is greater than a predetermined value or a case where a conductor, dielectric, or magnetic material constituting a part of the housing of RX exists within a predetermined distance from the power receiving antenna.

[0742] TX can recognize the possibility of a weak coupling state by receiving this information. The predetermined information is, for example, as follows.

[0743] Information acquired through communication based on the first standard (WPC standard) performed between the first communication unit 104 of TX and the first communication unit 204 of RX.

[0744] Information acquired through communication based on the second standard (a standard other than the WPC standard) performed between the second communication unit 109 of TX and the second communication unit 212 of RX.

[0745] Furthermore, the predetermined information is included in a signal strength packet transmitted from RX to TX in the Ping phase, and a notification thereof is provided. Alternatively, the predetermined information is included in an identification packet transmitted from RX to TX in the I&C phase, and a notification thereof is provided.

[0746] Alternatively, the predetermined information is included in an extended identification packet transmitted from RX to TX in the I&C phase, and notification thereof is provided. Alternatively, the predetermined information is included in a configuration packet transmitted from RX to TX in the I&C phase, and notification thereof is provided.

[0747] Alternatively, the predetermined information is included in the FOD status data packet transmitted from RX to TX in the negotiation phase, and notification thereof is provided. Alternatively, it may be a packet in the calibration phase or the power transfer phase, ie, RP1, RP2, or RP0.

[0748] In these packets, a 1-bit field indicating whether there is a possibility of a weak coupling state is set. When RX notifies TX that there is a possibility of a weak coupling state, "1" (or "0") is stored in this field. When RX notifies TX that there is no possibility of a weak coupling state, "0" (or "1") is stored in this field.

[0749] Alternatively, in these packets, a 1-bit field is set to indicate whether the structure near the power receiving antenna satisfies a predetermined condition. When the structure near the power receiving antenna satisfies the predetermined condition, RX stores "1" (or "0") in this field.

[0750] In addition, when RX notifies TX that the structure near the power receiving antenna does not meet the predetermined condition, "0" (or "1") is stored in this field. Alternatively, a FOD status data packet may be used. This packet includes a reference quality factor value and a reference resonant frequency value.

[0751] Processing is performed to make the reference quality factor value or the reference resonance frequency value greater than or less than a predetermined threshold value. These values ​​can be used as information indicating the possibility of the presence of a weak coupling state.

[0752] Alternatively, these values ​​may be used as information for indicating whether the structure near the power receiving antenna satisfies a predetermined condition. In the following, it is assumed that the description of “information for indicating whether there is a possibility of a weak coupling state” similarly applies to “information for indicating whether the structure near the power receiving antenna satisfies a predetermined condition”.

[0753] In addition to the information indicating whether there is a possibility of a weak coupling state, the above-mentioned package can also provide a notification of detailed information related to the hardware of the power receiving device. In addition, in addition to the information indicating whether the structure near the power receiving antenna satisfies a predetermined condition, the above-mentioned package can also provide a notification of detailed information related to the hardware of the power receiving device.

[0754] For example, there is information such as the size and type of the power receiving antenna (power receiving coil), etc. TX can recognize that there is a possibility that the coupling between the power transmitting antenna and the power receiving antenna will be weakened by receiving this information from RX.

[0755] Fig.26 is an explanatory flowchart of the processing in the first method. In S2501, RX transmits a packet including information indicating the coupling state between the power transmitting antenna and the power receiving antenna to TX. In S2501, TX receives a packet including information indicating the coupling state between the power transmitting antenna and the power receiving antenna from RX.

[0756] In S2502, TX determines whether the received packet includes information indicating a weak coupling state. When it is determined that the packet includes information indicating a weak coupling state ("Yes" in S2502), the process proceeds to the process of S2503, and TX cooperates with RX to perform control in the case of a weak coupling state.

[0757] In the third embodiment, specific control will be described. On the other hand, when it is determined that the packet does not include information indicating a weak coupling state (No in S2502), the process proceeds to the process of S2504, and TX and RX perform control in the case of a strong coupling state.

[0758] Alternatively, even if it is determined that the packet includes information indicating that there is no possibility of a weak coupling state, the process proceeds to the process of S2504, and TX and RX perform control in the case of a strong coupling state. An example of this control is control specified in the general WPC standard.

[0759] Will refer to Fig.26 Another example is described. In S2501, RX transmits a packet including information indicating a structure near the power receiving antenna to TX. In S2501, TX receives a packet including information indicating a structure near the power receiving antenna from RX.

[0760] In S2502, TX determines whether the received packet includes information indicating that the structure near the power receiving antenna satisfies the predetermined condition. When it is determined that the packet includes information indicating that the structure near the power receiving antenna satisfies the predetermined condition ("Yes" in S2502), the process proceeds to the process of S2503, and TX cooperates with RX to perform control in the case of a weak coupling state.

[0761] In the third embodiment, specific control will be described. On the other hand, when it is determined that the packet does not include information indicating that the structure near the power receiving antenna satisfies the predetermined condition (No in S2502), the process proceeds to the process of S2504, and TX and RX perform control in the case of a strong coupling state.

[0762] Alternatively, even if it is determined that the packet includes information indicating that the structure near the power receiving antenna does not satisfy the predetermined condition, the process proceeds to the process of S2504, and TX and RX perform control in the case of a strong coupling state. An example of this control is the control specified in the WPC standard.

[0763] Another method for identifying that the power transmitting device and the power receiving device are in a weak coupling state will be described. The coupling state between TX and RX is not only determined by the structure of RX, but may also be related to the structure of TX. Fig.14 In case of (D), the coupling state between TX and RX is determined by the size of the required predetermined area in RX and the size of the required predetermined area in TX.

[0764] Therefore, TX or RX determines the coupling state between TX and RX based on both the information TX has and the information RX has. Fig.26A description is given. It is assumed that the power transmitting device has known the structure of the housing near the power transmitting antenna. In addition, it is assumed that the power receiving device has known the structure of the housing near the power receiving antenna.

[0765] In S2501, TX receives a packet including information about the structure of the housing near the power receiving antenna from RX. In S2502, TX determines the coupling state between TX and RX based on the received information about the structure near the power receiving antenna and the information about the structure of the housing near the power transmitting antenna.

[0766] When it is determined that the coupling state between TX and RX is a weak coupling state ("Yes" in S2502), the process proceeds to the process of S2503, and TX and RX cooperate to perform control in the case of a weak coupling state. In the third embodiment, the specific control will be described. On the other hand, when it is determined that the coupling state between TX and RX is a strong coupling state ("No" in S2502), the process proceeds to the process of S2504, and TX and RX perform control in the case of a strong coupling state.

[0767] An example of this control is the control specified in the WPC standard. Alternatively, in S2501, RX receives a packet including information about the structure of the housing near the power transmitting antenna from TX. In S2502, RX determines the coupling state between TX and RX based on the received information about the structure near the power transmitting antenna and the information about the structure of the housing near the power receiving device.

[0768] When it is determined that the coupling state between TX and RX is a weak coupling state ("Yes" in S2502), the process proceeds to the process of S2503, and TX and RX cooperate to perform control in the case of a weak coupling state. In the third embodiment, the specific control will be described. On the other hand, when it is determined that the coupling state between TX and RX is a strong coupling state ("No" in S2502), the process proceeds to the process of S2504, and TX and RX perform control in the case of a strong coupling state.

[0769] An example of this control is the control specified in the WPC standard. Here, an example of information on the structure near the power transmitting antenna is shown below.

[0770] Information on whether the distance between the exterior of the TX housing and the power transmission antenna is greater than or equal to a predetermined value.

[0771] Information on whether a conductor, dielectric, magnetic material, or the like constituting a part of the casing of the TX is within a predetermined distance from the power transmission antenna.

[0772] Furthermore, an example of information on a structure near the power receiving antenna is shown below.

[0773] Information on whether the distance between the exterior of the housing of the RX and the power receiving antenna is greater than or equal to a predetermined value.

[0774] Information on whether a conductor, dielectric, magnetic material, or the like constituting a part of the housing of the RX is within a predetermined distance from the power receiving antenna.

[0775] Next, a second method for recognizing that the power transmitting device and the power receiving device are in a weak coupling state will be described. When there is a possibility of a weak coupling state, TX and RX measure the coupling state index between the power transmitting antenna and the power receiving antenna, and perform state judgment by comparing the measurement result with a predetermined threshold.

[0776] When the measurement result of the coupling state indicator is outside the threshold range, it can be identified that TX and RX are in a weak coupling state. The setting method of the state judgment threshold is similar to the threshold setting method for measuring the coupling state indicator. For example, the threshold is set by the first threshold setting method or the fourth threshold setting method.

[0777] TX and RX compare the measured value of the coupling state indicator with a threshold value. For example, when the measured value is less than the threshold value, it can be determined that TX and RX are in a weak coupling state, and when the measured value is greater than or equal to the threshold value, it can be determined that TX and RX are in a strong coupling state.

[0778] Fig. 27 is a flowchart showing the processing in the second method. In S2601, TX and RX set a threshold value of a coupling state indicator. In S2602, RX transmits a packet including information for calculating the coupling state indicator to TX. In S2602, TX receives a packet including information for calculating the coupling state indicator from RX.

[0779] TX measures the value required for calculating the coupling state index in S2603, and calculates the coupling state index in S2604. In S2605, TX determines whether the calculated coupling state index is less than the threshold value. When it is determined that the calculated coupling state index is less than the threshold value ("Yes" in S2605), the process proceeds to the process of S2606.

[0780] In addition, when it is determined that the calculated coupling state index is not less than the threshold value (No in S2605), the process proceeds to the process of S2607. In S2606, TX transmits a negative response NAK to RX, and TX cooperates with RX to perform control in the case of a weak coupling state. In the third embodiment, specific control will be described.

[0781] RX recognizes that TX and RX are in a weak coupling state by receiving a negative response NAK from TX. In addition, in S2607, TX transmits a positive response ACK to RX, and TX and RX perform control in the case where RX and TX are in a strong coupling state. An example of this control is the control specified in the WPC standard. RX recognizes that the state is a strong coupling state by receiving a positive response ACK from TX.

[0782] Although the above example describes the case where the TX calculates the coupling state indicator, the calculation of the coupling state indicator may be performed by the RX. Fig. 27 The flowchart of FIG. 2601 describes the operation in the case where the RX calculates the coupling state indicator. In S2601, the TX and the RX set a threshold value of the coupling state indicator.

[0783] In S2602, TX transmits a packet including information for calculating the coupling state indicator to RX. In S2602, RX receives a packet including information for calculating the coupling state indicator from TX. RX measures a value required for calculating the coupling state indicator in S2603, and calculates the coupling state indicator in S2604.

[0784] In S2605, the RX determines whether the calculated value of the coupling state index is less than the threshold value. When it is determined that the calculated value of the coupling state index is less than the threshold value ("Yes" in S2605), the process proceeds to the process of S2606. In addition, when it is determined that the calculated value of the coupling state index is not less than the threshold value ("No" in S2605), the process proceeds to the process of S2607.

[0785] In S2606, RX transmits a predetermined first packet to TX, and RX and TX cooperate to perform control in the case of a weak coupling state. In the third embodiment, the specific control will be described. TX recognizes that the state is a weak coupling state by receiving a predetermined first packet from RX. In addition, in S2607, RX transmits a predetermined second packet to TX, and RX and TX perform control in the case of a strong coupling state.

[0786] An example of this control is the control specified in the WPC standard. TX recognizes that the state is a strong coupling state by receiving a predetermined second packet from RX. In addition, there is a possibility that the coupling state between TX and RX may change over time due to positional offset, etc. Therefore, TX and RX may periodically perform the processing from S2601 to S2607 during the power transmission phase.

[0787] Next, a third method for recognizing that the power transmitting device and the power receiving device are in a weak coupling state will be described. When there is a possibility of a weak coupling state, a judgment process is performed as to whether the power received by RX from TX is less than a predetermined threshold. When the received power of RX is less than a predetermined threshold, it can be recognized that TX and RX are in a weak coupling state.

[0788] RX measures the received power value and notifies TX of the measurement result. For example, in the Ping phase, TX transmits DP and RX measures the voltage value of the received (power-receiving-specific) DP. RX stores the measured voltage value as a signal strength value in a signal strength packet.

[0789] RX transmits packets to TX, and TX receives packets from RX. The signal strength value is a value measured by RX as a voltage value for the power transmitted by TX. That is, the magnitude of the power receiving voltage value (measured value) is the strength of the coupling between the power transmitting antenna and the power receiving antenna.

[0790] TX compares the signal strength value in the packet with the threshold. When the signal strength value is greater than or equal to the threshold, TX determines that the state is a strong coupling state. When the signal strength value is less than the threshold, TX determines that the state is a weak coupling state.

[0791] The signal strength value is a value obtained by measuring the power transmitted by TX as a voltage value by RX. RX determines the strength of the coupling between the power transmitting antenna and the power receiving antenna based on the comparison result of the measured value of the signal strength value and the threshold value.

[0792] Regarding the threshold setting process in the third method, the first threshold setting method or the fourth threshold setting method in the threshold setting method in the measurement of the coupling state index can be particularly implemented, TX can hold the threshold in advance, and RX can notify TX of the threshold. Alternatively, TX and RX can hold the same threshold in advance.

[0793] Alternatively, in the calibration phase or the power transmission phase, RX may be implemented using a packet for notifying TX of the received power value. RP1, RP2, or RP0 includes information about the received power value measured by RX. This is a value obtained when RX measures the transmitted power of TX.

[0794] That is, the magnitude of the received power value measured by RX is the strength of the coupling between the power transmitting antenna and the power receiving antenna. TX compares the threshold with the received power value stored in RP1, RP2, or RP0. When the received power value is greater than or equal to the threshold, TX determines that the state is a strong coupling state. When the received power value is less than the threshold, TX determines that the state is a weak coupling state.

[0795] The received power value stored in the packet transmitted from RX to TX is the power value obtained when RX measures the transmitted power of TX. RX can determine the strength of the coupling between the transmitting antenna and the receiving antenna based on the comparison result of the measured received power value and the threshold.

[0796] Fig.28 27 is a flowchart showing the processing in the third method. In S2701, TX transmits DP. In S2702, TX determines whether a signal strength packet including information on the power receiving voltage value received by RX has been received from RX.

[0797] When TX has received the packet ("Yes" in S2702), the process proceeds to the process of S2704. When TX has not received the packet ("No" in S2702), the process proceeds to the process of S2703. In S2703, TX proceeds to the process of S2701 after waiting for a predetermined time, and retransmits DP.

[0798] In S2704, TX determines whether the signal strength value in the signal strength data packet is less than a predetermined value (threshold value). When it is determined that the signal strength value is less than the predetermined value ("Yes" in S2704), the process proceeds to the process of S2705, and TX cooperates with RX to perform control in the case of a weak coupling state.

[0799] In the third embodiment, specific control will be described. In addition, when it is determined that the signal strength value is not less than the predetermined value ("No" in S2704), the process proceeds to the process of S2706, and TX performs control in the case of a strong coupling state. An example of this control is the control specified in the WPC standard.

[0800] Fig.29 This is a flowchart specific to TX, which illustrates another example of the process in the third method. In S2801, TX starts power transmission to RX. In S2802, TX determines whether a received power packet including information on the received power value received by RX has been received from RX.

[0801] When TX has received the received power data packet ("Yes" in S2802), the process proceeds to the process of S2804. In addition, when TX has not received the packet ("No" in S2802), the process proceeds to the process of S2803, and after waiting for a predetermined time, it proceeds to the process of S2802.

[0802] In S2804, TX determines whether the received power value in the received power data packet is less than a predetermined value (threshold value). When it is determined that the received power value in the packet is less than the predetermined value ("Yes" in S2804), TX cooperates with RX in S2805 to perform control in the case of a weak coupling state.

[0803] In the third embodiment, specific control will be described. In addition, when it is determined that the received power value in the packet is not less than the predetermined value (No in S2804), TX performs control in the case of a strong coupling state in S2806. An example of this control is the control specified in the WPC standard.

[0804] In addition, the coupling state between TX and RX may change over time, for example, due to positional shift, etc. Therefore, TX and RX may periodically perform the processes from S2801 to S2806 during the power transfer phase.

[0805] Next, the fourth method for recognizing that the power transmitting device and the power receiving device are in a weak coupling state will be described. In the case of the weak coupling state in the first embodiment, the first method to the fourth method are cited as a method of placing TX to detect RX. For example, the AP or DP to be transmitted before the I&C stage is controlled so that an object can be detected even in a weak coupling state.

[0806] The TX can make a judgment related to the condition of the AP or DP that has detected the object, and recognize that the state is a weak coupling state. In the first method of the first embodiment, an example of periodically changing the power of the AP will be described.

[0807] like Fig.15 As shown in (A), when TX can detect an object using the AP with the minimum power, it is determined that the state is a strong coupling state. Fig.15 As shown in (B), when TX can detect an object only using the AP with the maximum power, it is determined that the state is a weak coupling state. That is, the coupling state between the power transmitting antenna and the power receiving antenna can be identified based on the power of the AP that can detect the object.

[0808] Furthermore, in the second method of the first embodiment, an example in which the threshold used when detecting the placement of an object using the AP is changed will be described. Fig.18 As shown in (A), when the threshold used when determining the placement of the object is the first threshold and the object has been detected by the AP, the TX determines that the state is the strong coupling state.

[0809] In addition, if Fig.18 As shown in (B), when the threshold used in determining the placement of the object is the third threshold and the object has been detected by the AP, the TX determines that the state is a weak coupling state. That is, the coupling state between the power transmitting antenna and the power receiving antenna can be identified based on the object placement determination threshold used to detect the object.

[0810] Furthermore, in the third method of the first embodiment, an example of changing the power of the DP according to the value of the physical quantity detected during AP transmission is described. Fig.19 As shown in (A), when the change in the detected physical quantity is within a range based on the first threshold, TX determines that the state is a strong coupling state.

[0811] In addition, if Fig.19 As shown in (B), when the change in the detected physical quantity is within the range based on the third threshold, TX determines that the state is a weak coupling state. That is, the coupling state of the power transmitting antenna and the power receiving antenna can be identified based on the comparison result of the change in the detected physical quantity and the threshold.

[0812] Furthermore, in the fourth method of the first embodiment, an example is described in which the power of the DP is periodically changed. Fig. 22 As shown in (B), when RX can be detected by DP with minimum power, TX determines that the state is a strong coupling state. Fig. 22 As shown in (C), when TX can detect RX only with the DP having the maximum power, it is determined that the state is a weak coupling state. That is, the coupling state between the power transmitting antenna and the power receiving antenna can be identified based on the power of the DP that can detect RX.

[0813] As described above, the power transmitting device and the power receiving device can more accurately recognize that they are in a weak coupling state based on the conditions (power or determination threshold, etc.) of the AP or DP that can detect the placement of the object (RX).

[0814] By utilizing the first to fourth methods described in the first embodiment or combining these methods as necessary, it is possible to more accurately recognize that the power transmitting device and the power receiving device are in a weakly coupled state.

[0815] According to this embodiment, it is possible to more accurately recognize a state in which the electromagnetic coupling between the power transmitting antenna and the power receiving antenna is weak.

[0816] [Third embodiment]

[0817] Next, a third embodiment of the present disclosure will be described. In this embodiment, an example of controlling the TX and RX in a weak coupling state will be described. Even in a weak coupling state, the TX can detect the placement of the RX by the method of the first embodiment, and the TX and RX can recognize the weak coupling state between the power transmitting antenna and the power receiving antenna by the method of the second embodiment.

[0818] Although TX transfers power to RX based on the recognition result, when power is transferred in a weakly coupled state, there are the following problems.

[0819] ・The noise leaking from the power transmitting antenna and the power receiving antenna to the surrounding area is large.

[0820] Communication performed by superimposing a signal on the TX power transmission waveform (voltage waveform or current waveform) becomes unstable.

[0821] ・The accuracy of foreign matter detection specified in the WPC standard has been reduced.

[0822] In order to solve the above problem, when TX detects the placement of RX and recognizes that TX and RX are in a weakly coupled state, TX and RX perform the following control.

[0823] First, a method of reducing the power transmitted from TX to RX will be described as a first method of suppressing noise leaking from the power transmitting antenna and the power receiving antenna to the surroundings. When it is recognized that TX and RX are in a weak coupling state, control is performed to limit the power by reducing the power transmitted compared to the case of a strong coupling state.

[0824] The power source of the power transmitted from the TX may also be a noise source. Therefore, the noise leaking from the power transmitting antenna and the power receiving antenna to the surroundings can be suppressed by reducing the power transmission. The control unit 101 of the TX controls the power transmission unit 103 and sets the power transmission power to be less than or equal to a predetermined power value. The power transmitted from the power transmission antenna 105 is limited to a predetermined power value or less.

[0825] Another implementation method for reducing the transmission power of TX or a method for reducing the reception power of RX is a method in which TX and RX negotiate in a negotiation phase to determine GP. RX transmits the requested load power information to TX.

[0826] The requested load power is the value of the power requested from RX to TX so that the power is output to the load. This power is the power consumed by the load. The load refers to a system that supplies power from RX or a power receiving unit of RX, and examples of the load include the charging unit 206 and the battery 207 of RX.

[0827] On the other hand, TX has a potential load power value or a negotiable load power value in advance. The potential load power has a maximum load power value (highest load power level) of load power that can be negotiated by TX and output (supplied) to the load of RX.

[0828] In addition, the negotiable load power is the maximum load power value (highest load power level) of the load power that can be negotiated by TX and output (supplied) to RX during a predetermined period or under predetermined conditions. If the value of the requested load power is less than the value of the negotiable load power, the negotiation is established.

[0829] TX and RX set the value of the requested load power to the value of GP and keep the set value in the memory. That is, TX receives the value of the requested load power from RX, and when the value is less than the value of the negotiable load power, transmits an affirmative response ACK to RX.

[0830] TX and RX set the value of the requested load power to the value of GP and keep the set value in the memory. TX also receives the value of the requested load power from RX and transmits a negative response NAK to RX when the value is greater than the value of the negotiable load power.

[0831] RX decreases the value of the requested load power and retransmits information indicating the value of the requested load power to TX. RX repeats this process until a positive response ACK is received from TX. When RX receives a positive response ACK from TX, TX and RX set the value of the requested load power to the value of GP and hold the set value in the memory.

[0832] When the value of GP is set to be less than or equal to a predetermined value, the transmission power of TX can be reduced, and the reception power of RX can be reduced. Thus, TX sets the potential load power or the negotiable load power to a predetermined value or less.

[0833] Alternatively, RX sets the value of the requested load power to a predetermined value or less. In addition, the above control may be performed in the renegotiation phase. In addition, TX may switch the inverter provided in the power transmission unit 103 from a switching circuit having a full-bridge configuration to a switching circuit having a half-bridge configuration.

[0834] In the above example, the operation of TX and RX when TX and RX recognize that the state is a weak coupling state is described. On the other hand, when a foreign object (metal sheet, etc.) between the power transmitting antenna and the power receiving antenna is removed, the coupling state between the power transmitting antenna and the power receiving antenna changes from a weak coupling state to a strong coupling state.

[0835] Alternatively, when the positional offset between the power transmitting antenna and the power receiving antenna is eliminated and the power transmitting antenna and the power receiving antenna are arranged to face each other, the coupling state between the power transmitting antenna and the power receiving antenna changes from the weak coupling state to the strong coupling state. Alternatively, as the distance between the power transmitting antenna and the power receiving antenna decreases, the coupling state between the power transmitting antenna and the power receiving antenna changes from the weak coupling state to the strong coupling state.

[0836] The operation when the coupling state between the power transmitting antenna and the power receiving antenna changes from a weak coupling state to a strong coupling state will be described. TX and RX calculate (measure) the coupling state index by the coupling state index measurement method, and compare the calculated coupling state index with the set threshold. The setting method of the threshold is as described above.

[0837] In addition, when it is recognized that TX and RX are in a strong coupling state, control is performed to increase the transmission power of TX (increase the reception power of RX) compared to the case of a weak coupling state. In this case, the value of GP is set to a predetermined value or more so that the transmission power of TX can be increased (the reception power of RX can be increased).

[0838] Thus, TX sets the potential load power or the negotiable load power to a predetermined value or more. Alternatively, RX sets the value of the requested load power to a predetermined value or more. In addition, the above control may be performed in a renegotiation phase.

[0839] In addition, TX can switch the inverter provided in the power transmission unit 103 from a switching circuit having a half-bridge configuration to a switching circuit having a full-bridge configuration. Alternatively, in TX or RX, at a predetermined timing in the power transmission phase, the coupling state index is calculated (measured) by a coupling state index measurement method, and the coupling state is judged by comparing the calculated coupling state index with a set threshold value.

[0840] The predetermined timing occurs at a prescribed interval, or occurs when TX has received a predetermined packet from RX. Alternatively, the predetermined timing occurs when RX has received a predetermined packet from TX. TX or RX can control the transmission power by the above method according to the determination result of the coupling state.

[0841] Next, a method of changing the frequency band of the TX transmission waveform will be described as a second method of suppressing noise leaking from the power transmitting antenna and the power receiving antenna to the surroundings. Noise is generated in the frequency band used for power transmission from the power transmitting antenna to the power receiving antenna (hereinafter referred to as the usable frequency band).

[0842] In addition, harmonic noise is generated in a frequency band higher than the usable frequency band. When the frequency band in which noise is generated is used by other systems, there is a possibility that the other systems will fail. Therefore, when the state is identified as a weak coupling state, TX and RX perform control for changing the usable frequency band from the first frequency band to the second frequency band.

[0843] The influence on other systems can be suppressed by changing the frequency band of the noise leaking from the power transmitting antenna and the power receiving antenna to the surrounding. The usable frequency band specified in the WPC standard is in the range of 87kHz to 205kHz. When TX and RX recognize that the state is a weak coupling state, the usable frequency band is changed to a band lower than 87kHz or a band higher than 205kHz.

[0844] In the above example, the operation of TX and RX when TX and RX recognize that the state is a weak coupling state is described. The operation in the case where the state changes and the coupling state between the power transmitting antenna and the power receiving antenna changes from a weak coupling state to a strong coupling state will be described. TX and RX calculate (measure) the coupling state index by the coupling state index measurement method, and compare the calculated coupling state index with the set threshold value.

[0845] Furthermore, when TX and RX recognize that the state is a strong coupling state, control is performed to change the usable frequency band from the second frequency band to the first frequency band. Alternatively, in the power transmission phase, TX or RX calculates (measures) a coupling state index by a coupling state index measurement method at a predetermined timing, and determines the coupling state by comparing the calculated coupling state index with a set threshold value.

[0846] The predetermined timing occurs at a predetermined interval, or occurs when TX receives a predetermined packet from RX. Alternatively, the predetermined timing occurs when RX receives a predetermined packet from TX. TX or RX can control the usable frequency band by the above method according to the judgment result.

[0847] Next, a method of using a noise suppression circuit will be described as a third method for suppressing noise leaking from the power transmitting antenna and the power receiving antenna to the surroundings. TX or RX has a noise suppression circuit. For example, the noise suppression circuit is placed on the circuit board of TX and is connected to the power transmitting antenna 105, the power transmitting unit 103 and the first communication unit 104, and includes an inductor, a capacitor, a resistor, a filter and a noise suppression component (ferrite, etc.).

[0848] In addition, the noise suppression circuit is placed on the circuit board of RX and is connected to the power receiving antenna 205, the power receiving unit 203 and the first communication unit 204, and includes an inductor, a capacitor, a resistor, a filter and a noise suppression component (ferrite, etc.). The noise suppression circuit is configured according to the usable frequency band.

[0849] The reason is that the noise source is based on the transmitted power of TX, and the frequency band of the generated noise is determined according to the usable frequency band. Therefore, TX or RX has a noise suppression circuit for each usable frequency band.

[0850] When TX and RX recognize that the state is a weakly coupled state, noise suppression control is performed by changing the usable frequency band from the first frequency band to the second frequency band and switching to a noise suppression circuit corresponding to the changed usable frequency band.

[0851] In the above example, the operation of TX and RX when TX and RX recognize that the state is a weak coupling state is described. The operation is described in the case where the state changes and the coupling state between the power transmitting antenna and the power receiving antenna changes from a weak coupling state to a strong coupling state. TX and RX calculate (measure) the coupling state index by the coupling state index measurement method, and compare the calculated coupling state index with the set threshold value.

[0852] Furthermore, TX and RX recognize that the state is a strong coupling state. When the strong coupling state has been recognized, control is performed for changing the usable frequency band from the second frequency band to the first frequency band and switching to the noise suppression circuit corresponding to the changed usable frequency band.

[0853] Alternatively, in the power transmission phase, TX or RX calculates (measures) the coupling state index by a coupling state index measurement method at a predetermined timing, and compares the calculated coupling state index with a set threshold value to determine the coupling state. The predetermined timing occurs at a prescribed predetermined interval, or occurs when TX receives a predetermined packet from RX.

[0854] Alternatively, when RX receives a predetermined packet from TX, the predetermined timing occurs. According to the determination result, TX or RX controls the usable frequency band by the above method, and performs control for switching to the noise suppression circuit corresponding to the changed usable frequency band.

[0855] Next, a method of changing the frequency shift modulation parameters to be used by TX for communication with RX will be described as a fourth method of suppressing noise leaking from the power transmitting antenna and the power receiving antenna to the surroundings. In addition, a method of changing the load modulation or amplitude modulation parameters to be used by TX for communication with TX will be described.

[0856] In the communication of information transmission from TX to RX, the first communication unit 104 of TX performs frequency shift modulation of the electromagnetic wave output from the power transmission antenna 105. At this time, TX changes the frequency of the carrier wave (power transmission waveform) and transmits information.

[0857] When two frequencies are used, TX associates a relatively high frequency signal with first information (e.g., "1") and associates a relatively low frequency signal with second information (e.g., "0"). TX transmits (power transmission) during switching between the two frequencies and transmits information to RX.

[0858] In addition, TX switches the frequency of the carrier to a first operating frequency corresponding to the unmodulated state (indicated by fop) and a second operating frequency corresponding to the modulated state (indicated by fmod), and transmits information to RX. fop and fmod are defined by two parameters.

[0859] The first parameter is polarity, and indicates whether the difference between fmod and fop (fmod-fop) is positive or negative. Due to the change in polarity, noise of a specific frequency band can be suppressed.

[0860] There is a possibility that noise in the frequency band used in communication or harmonic noise in a frequency band higher than this frequency band may cause malfunction of other systems. By changing the polarity, the frequency band used in communication can be changed. The second parameter is the modulation index (frequency shift, modulation degree or depth), and indicates the size (absolute value) of the difference between fmod and fop.

[0861] The larger the modulation index, the larger the difference between fmod and fop. Therefore, the bandwidth of the noise of a specific frequency band leaking from the power transmitting antenna and the power receiving antenna to the surrounding is wider. In the case of a weak coupling state, strong noise may occur in a wider bandwidth during power transmission.

[0862] Therefore, when the state is recognized as a weak coupling state, TX and RX control the values ​​of the first parameter and the second parameter so that these values ​​become predetermined values ​​in communication when information is transmitted from TX to RX. For example, TX and RX control so that when they are recognized as being in a weak coupling state, the polarity is negative (or positive).

[0863] By changing the polarity, the frequency band used for communication can be controlled, so that noise in a specific frequency band leaking from the power transmitting antenna and the power receiving antenna to the surroundings can be suppressed.

[0864] In addition, when TX and RX recognize that the state is a weak coupling state, control is performed so that the modulation index (frequency shift, modulation degree or depth) is reduced. Since the difference between fmod and fop is reduced, the bandwidth of the noise in a specific frequency band leaking from the power transmitting antenna and the power receiving antenna to the surrounding can be narrowed.

[0865] In the above example, the operation of TX and RX when TX and RX recognize that the state is a weak coupling state is described. The operation when the state changes and the coupling state between the power transmitting antenna and the power receiving antenna changes from a weak coupling state to a strong coupling state will be described. TX and RX calculate (measure) the coupling state index by the coupling state index measurement method, and compare the calculated coupling state index with the set threshold value.

[0866] In addition, TX and RX recognize that the state is a strongly coupled state. When TX and RX recognize that the state is a strongly coupled state, control is performed so that the polarity becomes positive (or negative) or the modulation index (frequency shift, modulation degree or depth) increases.

[0867] Alternatively, in the power transmission phase, TX or RX calculates (measures) the coupling state index by a coupling state index measurement method at a predetermined timing, and compares the calculated coupling state index with a set threshold value to determine the coupling state. The predetermined timing occurs at a prescribed predetermined interval, or occurs when TX receives a predetermined packet from RX.

[0868] Alternatively, when RX receives a predetermined packet from TX, the predetermined timing occurs. TX or RX controls at least one of the polarity and the modulation index by the above method according to the judgment result.

[0869] The first parameter and the second parameter may be included in a configuration data packet transmitted by the RX in the I&C phase. When the state is identified as a weak coupling state, the RX sets the values ​​of the two parameters related to frequency shift modulation in the configuration data packet to predetermined values ​​and transmits the packet to the TX.

[0870] TX performs frequency shift modulation based on the two parameter values ​​in the received data packet and transmits the information to RX. The packet used by RX to transmit the values ​​of the first parameter and the second parameter to TX is a signal strength data packet or an identification data packet.

[0871] Alternatively, the packet may be an extended identification data packet. Alternatively, the packet may be a packet in the calibration phase or the power transfer phase, ie, RP1, RP2, or RP0. Hereinafter, these packets are collectively referred to as "predetermined packets".

[0872] Next, a method of changing load modulation or amplitude modulation parameters used when RX performs communication for transmitting information to TX will be described. The first communication unit 204 of RX performs load modulation or amplitude modulation of electromagnetic waves output from the power transmission antenna 105 of TX and transmits information to TX for communication.

[0873] At this time, RX transmits information by changing the amplitude of the carrier (transmission waveform). When two amplitudes are used, RX associates a relatively large amplitude signal with the first information (e.g., "1") and a relatively small amplitude signal with the second information (e.g., "0"). RX transmits information to TX by superimposing the signal on the transmission waveform while switching the amplitude.

[0874] RX switches the amplitude of the carrier wave between the following two types of amplitudes and transmits the information to TX.

[0875] Amplitude Amp_A in the Hi-State state (relatively large amplitude).

[0876] Amplitude Amp_B in the low-state state (relatively small amplitude).

[0877] The size of the difference between Amp_A and Amp_B is called the modulation degree (modulation depth). Since the change in the frequency of the carrier increases as the modulation degree increases, the bandwidth of the noise of a specific frequency band leaking from the power transmitting antenna and the power receiving antenna to the surrounding increases. Therefore, in the case of a weak coupling state, strong noise may occur in a wider bandwidth during power transmission.

[0878] Therefore, TX and RX perform control so that when the state is identified as a weak coupling state, the modulation degree becomes a predetermined value in the communication from RX to TX. More specifically, control is performed so that the modulation degree is reduced and the magnitude of the difference between the amplitude Amp_A and the amplitude Amp_B is reduced. Therefore, the bandwidth of the noise of a specific frequency band leaking from the power transmitting antenna and the power receiving antenna to the surrounding can be narrowed.

[0879] In the above example, the operation of TX and RX when TX and RX recognize that the state is a weak coupling state is described. The operation when the state changes and the coupling state between the power transmitting antenna and the power receiving antenna changes from a weak coupling state to a strong coupling state will be described.

[0880] TX and RX calculate (measure) the coupling state index by the coupling state index measurement method, and compare the calculated coupling state index with the set threshold value. In addition, TX and RX perform control so that when the state is recognized as a strong coupling state, the modulation degree increases.

[0881] Alternatively, in the power transmission phase, the TX or RX calculates (measures) the coupling state index by a coupling state index measuring method at a predetermined timing, and compares the calculated coupling state index with a set threshold value to judge the coupling state.

[0882] The predetermined timing occurs at a predetermined interval or when TX receives a predetermined packet from RX. Alternatively, the predetermined timing occurs when RX receives a predetermined packet from TX. TX or RX controls the modulation degree by the above method according to the judgment result.

[0883] When performing the above process, RX may inform TX in advance of the modulation degree to be used for the predetermined packet, for example, the modulation degree information used in the configuration data packet transmitted by RX in the I&C phase may be included.

[0884] When the state is recognized as the weak coupling state, the RX sets the value of the parameter (modulation degree) related to the load modulation or amplitude modulation in the configuration data packet to a predetermined value, and transmits the packet to the TX.

[0885] TX controls the power transmission waveform based on the value of the parameter (modulation degree) related to load modulation or amplitude modulation included in the received packet. In addition, the packet to be used by RX to transmit information on the parameter (modulation degree) related to load modulation or amplitude modulation to TX may be the above-mentioned predetermined packet.

[0886] Next, a method for changing a signal modulation scheme in communication related to information transmission from TX to RX and communication related to information transmission from RX to TX will be described as a fifth method for suppressing noise leaking from the power transmitting antenna and the power receiving antenna to the surroundings.

[0887] There is a spread spectrum scheme as an example of a signal modulation scheme, and communication is performed using a signal having a wide frequency band exceeding a frequency band required for information transmission. Specifically, as a first scheme, there is a direct sequence spread spectrum (DSSS).

[0888] For example, when the state is identified as a weak coupling state in transmission from TX to RX, the first communication unit 104 of TX performs arithmetic processing on the original signal modulated by frequency shift modulation using a spread signal, which is called a spread code (PN: pseudo noise) or pseudo random noise.

[0889] The first scheme is a scheme of directly spreading the energy to a frequency band wider than the frequency band required for transmission of the original signal. TX transmits the signal processed in the operation process to RX. RX keeps the data of the spread signal used for operation process by TX in the memory 208 in advance. RX inversely converts the received signal using the spread signal and obtains the original signal modulated by frequency shift modulation.

[0890] In addition, when the state is identified as a weak coupling state during transmission from RX to TX, the first communication unit 204 of RX performs operation processing using the extended signal for the original signal modulated by load modulation or amplitude modulation. RX transmits the signal processed in the operation processing to TX. TX keeps the data of the extended signal used for operation processing by RX in the memory 106 in advance.

[0891] TX inversely converts the received signal using the spread signal and obtains the original signal modulated by load modulation or amplitude modulation. By using the first scheme, the size (level) of noise in a specific frequency band leaking from the power transmitting antenna and the power receiving antenna to the surroundings can be reduced.

[0892] In the above example, the operation of TX and RX when TX and RX recognize that the state is a weak coupling state is described. The operation when the state changes and the coupling state between the power transmitting antenna and the power receiving antenna changes from a weak coupling state to a strong coupling state will be described.

[0893] TX and RX calculate (measure) the coupling state index by the coupling state index measurement method, and compare the calculated coupling state index with the set threshold value. In addition, when TX and RX recognize that the state is a strong coupling state, control is performed so that communication is performed without performing a predetermined operation process.

[0894] The predetermined operation processing is operation processing using a spread signal called a spread code (PN: pseudo noise) or pseudo random noise for an original signal modulated by frequency shift modulation or an original signal modulated by load modulation or amplitude modulation.

[0895] Alternatively, in the power transmission phase, TX or RX calculates (measures) the coupling state index by a coupling state index measurement method at a predetermined timing, and compares the calculated coupling state index with a set threshold value to determine the coupling state. The predetermined timing occurs at a prescribed predetermined interval, or occurs when TX receives a predetermined packet from RX.

[0896] Alternatively, when RX receives a predetermined packet from TX, the predetermined timing occurs. According to the judgment result, TX or RX uses the extended signal to control the operation process for the original signal modulated by frequency shift modulation or the original signal modulated by load modulation or amplitude modulation by the above method.

[0897] The second scheme is a frequency hopping scheme (FHSS: Frequency Hopping Spread Spectrum) which divides a frequency band allocated for communication into a plurality of frequency slots and switches the frequency slot used for communication at high speed in a short time according to a frequency switching pattern.

[0898] That is, different frequency bands in a wide frequency band are used for transmission during switching in a short period of time. The frequency slots are also called "hopping channels". The frequency switching pattern is called a hopping sequence or hopping pattern. TX and RX can receive signals of their respective frequency bands according to a predetermined hopping sequence and obtain the original signal.

[0899] For example, when the state is identified as a weak coupling state in the transmission from TX to RX, the first communication unit 104 of TX performs a process of transmitting the original signal modulated by frequency shift modulation using the frequency slot according to the frequency hopping sequence. TX transmits the processed signal to RX. RX keeps the frequency hopping sequence data used by TX for processing in the memory 208 in advance.

[0900] RX performs inverse conversion on the received signal according to the frequency hopping sequence and obtains the original signal modulated by frequency shift modulation. In addition, when the state is identified as a weak coupling state in the transmission from RX to TX, the first communication unit 204 of RX performs a process of transmitting the original signal modulated by load modulation or amplitude modulation using the frequency slot according to the frequency hopping sequence.

[0901] RX transmits the processed signal to TX. TX keeps the frequency hopping sequence data used by RX for processing in the memory 106 in advance. TX inversely converts the received signal according to the frequency hopping sequence and obtains the original signal modulated by load modulation or amplitude modulation. By using the second scheme, the size (level) of the noise in the specific frequency band leaking from the power transmitting antenna and the power receiving antenna to the surrounding can be reduced.

[0902] In the above example, the operation of TX and RX when TX and RX recognize that the state is a weak coupling state is described. The operation when the state changes and the coupling state between the power transmitting antenna and the power receiving antenna changes from a weak coupling state to a strong coupling state will be described.

[0903] TX and RX calculate (measure) the coupling state index by the coupling state index measurement method described above, and compare the calculated coupling state index with the set threshold. In addition, when TX and RX recognize that the state is a strong coupling state, control is performed so that communication is performed without performing a predetermined process.

[0904] The predetermined processing is a process of transmitting an original signal modulated by frequency shift modulation or an original signal modulated by load modulation or amplitude modulation using a frequency slot according to a frequency hopping sequence. Alternatively, in the power transmission stage, TX or RX calculates (measures) a coupling state index by a coupling state index measurement method at a predetermined timing, and compares the calculated coupling state index with a set threshold value to judge the coupling state.

[0905] The predetermined timing occurs at a prescribed predetermined interval, or occurs when TX receives a predetermined packet from RX. Alternatively, the predetermined timing occurs when RX receives a predetermined packet from TX.

[0906] According to the determination result, TX or RX controls the process of transmitting the original signal modulated by frequency shift modulation or the original signal modulated by load modulation or amplitude modulation using the frequency slot according to the frequency hopping sequence through the above method.

[0907] The third scheme is a scheme that performs processing of the direct spreading scheme and also performs processing of the frequency hopping scheme. By combining these two schemes, the magnitude (level) of noise in a specific frequency band leaking from the power transmitting antenna and the power receiving antenna to the surroundings can be further reduced.

[0908] Information for indicating which one of the first to third schemes is used or whether the scheme is supported may be included in a configuration packet transmitted by the RX in the I&C stage.

[0909] When the state is recognized as the weak coupling state, the RX stores data (eg, “1”) indicating use of any one of the first to third schemes in a predetermined field within the configuration data packet.

[0910] Alternatively, "1" as data corresponding to the use of the first scheme, "2" as data corresponding to the use of the second scheme, and "3" as data corresponding to the use of the third scheme are stored in this field. When the state is recognized as not being a weakly coupled state, RX does not use any...

Claims

1. A power transmission device, comprising: a power transmission component configured to wirelessly transmit power to a power receiving device via a power transmission antenna; a detection component configured to detect an object by using the power transmission component to output a signal under a plurality of different conditions; as well as a control component configured to control the power transmission component, When the detection unit detects the power receiving device and the electromagnetic coupling between the power transmitting antenna and the power receiving antenna of the power receiving device is weaker than the electromagnetic coupling in a predetermined state, the control unit changes the process for controlling the power transmitting unit.

2. The power transmission device according to claim 1, wherein: The control means performs control so that the detection means detects an object using a first signal under a plurality of different conditions output from the power transmitting antenna and activates the power receiving device using a second signal output from the power transmitting antenna.

3. The power transmission device according to claim 2, wherein: The control unit outputs a plurality of the first signals having different power values ​​from the power transmitting antenna, and determines the power of the second signal by identifying the electromagnetic coupling state between the power transmitting antenna and the power receiving antenna corresponding to the power of the first signal capable of detecting an object.

4. The power transmission device according to claim 2, wherein: When an object has not been detected using the first signal, the control unit outputs a plurality of second signals having different power values ​​from the power transmitting antenna, and identifies an electromagnetic coupling state between the power transmitting antenna and the power receiving antenna corresponding to the power of the second signal capable of detecting the power receiving device.

5. The power transmission device according to claim 4, wherein: The control component identifies whether the state of the electromagnetic coupling between the power transmitting antenna and the power receiving antenna is a first state in which the electromagnetic coupling is weaker than the electromagnetic coupling in the predetermined state or a second state different from the first state, and determines the power of the second signal when the state is identified as the first state to be higher than the power of the second signal when the state is identified as the second state.

6. The power transmission device according to claim 2, wherein: When receiving a signal in response to the second signal from the power receiving device, the control means performs control for changing the power of the second signal according to a voltage value of the second signal received by the power receiving device.

7. A power transmission device, comprising: a power transmission component configured to wirelessly transmit power to a power receiving device via a power transmission antenna; a detection member configured to detect an object by outputting a signal via the power transmission member; an identification unit configured to identify the power receiving device detected by the detection unit, and to identify whether a state of electromagnetic coupling between the power transmitting antenna and the power receiving antenna of the power receiving device is a first state in which the electromagnetic coupling is weaker than the electromagnetic coupling in a predetermined state or a second state different from the first state; as well as a control component configured to control the power transmission component, The control means changes a process for controlling the power transmission means according to the state identified by the identification means.

8. The power transmission device according to claim 7, wherein: The control means controls the power transmission means so that the power outputted via the power transmission antenna becomes higher power when the recognition means recognizes that the state is the first state than when the recognition means recognizes that the state is the second state.

9. The power transmission device according to claim 7, comprising a communication component configured to communicate with the power receiving device, in, The identification means acquires information indicating a possibility that the first state exists from the power receiving device through the communication means.

10. The power transmission device according to claim 7, wherein: The identification component performs state determination processing by comparing a measurement result of a coupling state index indicating the electromagnetic coupling state between the power transmitting antenna and the power receiving antenna with a threshold value, and identifies that the state is the first state when the measurement result of the coupling state index is outside the range of the threshold value.

11. The power transmission device according to claim 7, wherein: The recognition unit recognizes the first state when the value of the electric power received by the power receiving device or the value of the power receiving voltage is smaller than a threshold value.

12. The power transmission device according to claim 7, wherein: The control means performs a control process in which the detection means detects an object using a first signal output from the power transmitting antenna and activates the power receiving device detected by a second signal output from the power transmitting antenna.

13. The power transmission device according to claim 12, in, The control section performs control for periodically changing the power of the first signal or the second signal, and When an object is detected using only the first signal or the second signal with maximum power, the recognition component recognizes that the state is the first state.

14. The power transmission device according to claim 12, in, The control means performs control for changing a threshold used in determining detection of an object corresponding to the first signal, and When an object is detected using the first signal corresponding to a minimum threshold, the recognition component recognizes that the state is the first state.

15. The power transmission device according to claim 12, in, When the first signal having the same electric power is output from the power transmission antenna, the control means measures or calculates an electric physical quantity, and When the change in the physical quantity is within a range based on a threshold value, the identification component identifies that the state is the first state.

16. A power transmission device, comprising: a power transmission component configured to wirelessly transmit power to a power receiving device via a power transmission antenna; a detection component configured to detect an object by utilizing a signal output by the power transmission component; as well as a control unit configured to perform control for the power transmission unit in accordance with a state of electromagnetic coupling between the power transmission antenna and the power receiving antenna of the power receiving device, When the electromagnetic coupling between the power transmitting antenna and the power receiving antenna is weaker than the electromagnetic coupling in a predetermined state, the control component performs one or more types of control among a first control, a second control and a third control, wherein the first control is used to suppress noise leakage from the power transmitting antenna and the power receiving antenna to the surroundings, the second control is used to suppress instability of communication between the power transmitting device and the power receiving device, and the third control is used to suppress degradation of detection accuracy of objects other than the power receiving device.

17. The power transmission device according to claim 16, wherein: In the first control, the control means performs control for reducing the transmission power compared with a case where the electromagnetic coupling between the power transmitting antenna and the power receiving antenna is stronger than the electromagnetic coupling in the predetermined state.

18. The power transmission device according to claim 16, wherein: In the first control, the control means performs control for changing a frequency band used for power transmission or control for switching to a noise suppression circuit corresponding to the frequency band.

19. The power transmission device according to claim 16, wherein: In the first control, the control means performs control for changing a modulation parameter or a modulation scheme used in communication with the power receiving device.

20. The power transmission device according to claim 16, wherein: In the first control, the control means performs control for switching the power transmitting antenna from a first power transmitting antenna among a plurality of power transmitting antennas to a second power transmitting antenna having a different size.

21. The power transmission device according to claim 16, wherein: In the first control, the control means performs control for changing a circuit so that a quality factor of a power transmission-related circuit including the power transmission antenna is larger.

22. The power transmission device according to claim 16, wherein: In the second control, the control means performs control for changing a modulation parameter used in communication with the power receiving apparatus, or control for changing a communication scheme related to communication with the power receiving apparatus.

23. The power transmission device according to claim 16, wherein: In the third control, the control means performs control for detecting an object different from the power receiving device by comparing a measurement result of a coupling state index indicating an electromagnetic coupling state between the power transmitting antenna and the power receiving antenna with a threshold value.

24. The power transmission device according to claim 16, wherein: In the third control, the control means performs control for detecting an object different from the power receiving device by comparing a detected value or a temperature increase rate of the temperature of the power transmitting device or the power receiving device with a threshold value.

25. The power transmission device according to claim 23, wherein: The control component determines whether the object exists by setting the threshold to a first threshold in a first state in which the electromagnetic coupling between the power transmitting antenna and the power receiving antenna is weaker than the electromagnetic coupling in the predetermined state, and setting the threshold to a second threshold in a second state in which the electromagnetic coupling between the power transmitting antenna and the power receiving antenna is stronger than the electromagnetic coupling in the predetermined state.

26. A control method performed by a power transmitting device, the power transmitting device being capable of transmitting power to a power receiving device through wireless power transmission, the control method for the power transmitting device comprising: a power transmission step for transmitting power to the power receiving device via a power transmission antenna in a power transmission component; a detection step for detecting an object by outputting a signal under a plurality of different conditions in the power transmission component; as well as a control step for controlling the power transmission component in a control component, In the control step, when the power receiving device is detected in the detection step and the electromagnetic coupling between the power transmitting antenna and the power receiving antenna of the power receiving device is weaker than the electromagnetic coupling in a predetermined state, the control unit changes the processing for controlling the power transmitting unit.

27. A control method performed by a power transmitting device, the power transmitting device being capable of transmitting power to a power receiving device through wireless power transmission, the control method for the power transmitting device comprising: a power transmission step for transmitting power to the power receiving device via a power transmission antenna in a power transmission component; a detection step for detecting an object by outputting a signal in the power transmission component; an identification step for identifying, in an identification unit, the power receiving device detected in the detection step, and identifying whether a state of electromagnetic coupling between the power transmitting antenna and the power receiving antenna of the power receiving device is a first state in which the electromagnetic coupling is weaker than the electromagnetic coupling in a predetermined state or a second state different from the first state; as well as a control step for controlling the power transmission component in a control component, Here, in the control step, the control means changes a process for controlling the power transmission means according to the state identified by the identification means.

28. A control method performed by a power transmitting device, the power transmitting device being capable of transmitting power to a power receiving device through wireless power transmission, the control method for the power transmitting device comprising: a power transmission step for transmitting power to the power receiving device via a power transmission antenna in a power transmission component; a detection step for detecting the object by outputting a signal in the power transmission component; as well as a control step for performing control of the power transmission unit in accordance with the electromagnetic coupling state between the power transmission antenna and the power receiving antenna of the power receiving device in the control unit, In the control step, when the electromagnetic coupling between the power transmitting antenna and the power receiving antenna is weaker than the electromagnetic coupling in a predetermined state, the control component performs one or more types of control among a first control, a second control and a third control, wherein the first control is used to suppress noise leaking from the power transmitting antenna and the power receiving antenna to the surroundings, the second control is used to suppress instability of communication between the power transmitting device and the power receiving device, and the third control is used to suppress degradation of detection accuracy of objects other than the power receiving device.

29. A storage medium storing a computer program, the computer program being used to cause a computer to execute: a power transmission step for transmitting power to the power receiving device via the power transmission antenna in the power transmission component; a detection step for detecting an object by outputting a signal under a plurality of different conditions in the power transmission component; as well as a control step for controlling the power transmission component in a control component, In the control step, when the power receiving device is detected in the detection step and the electromagnetic coupling between the power transmitting antenna and the power receiving antenna of the power receiving device is weaker than the electromagnetic coupling in a predetermined state, the control unit changes the processing for controlling the power transmitting unit.

30. A storage medium storing a computer program, the computer program being used to cause a computer to execute: a power transmission step for transmitting power to the power receiving device via the power transmission antenna in the power transmission component; a detection step for detecting an object by outputting a signal in the power transmission component; an identification step for identifying, in an identification unit, the power receiving device detected in the detection step, and identifying whether a state of electromagnetic coupling between the power transmitting antenna and the power receiving antenna of the power receiving device is a first state in which the electromagnetic coupling is weaker than the electromagnetic coupling in a predetermined state or a second state different from the first state; as well as a control step for controlling the power transmission component in a control component, Here, in the control step, the control means changes a process for controlling the power transmission means according to the state identified by the identification means.

31. A storage medium storing a computer program, the computer program being used to cause a computer to execute: a power transmission step for transmitting power to the power receiving device via the power transmission antenna in the power transmission component; a detection step for detecting the object by outputting a signal in the power transmission component; as well as a control step for performing control of the power transmission unit in accordance with the electromagnetic coupling state between the power transmission antenna and the power receiving antenna of the power receiving device in the control unit, In the control step, when the electromagnetic coupling between the power transmitting antenna and the power receiving antenna is weaker than the electromagnetic coupling in a predetermined state, the control component performs one or more types of control among a first control, a second control and a third control, wherein the first control is used to suppress noise leakage from the power transmitting antenna and the power receiving antenna to the surroundings, the second control is used to suppress instability of communication between the power transmitting device and the power receiving device, and the third control is used to suppress degradation of detection accuracy of objects other than the power receiving device.

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