Power transmission apparatus, power reception apparatus, wireless power transmission system, control method of power transmission apparatus, and storage medium

Abstract

In order to perform power transmission control and power reception control on the basis of a plurality of state detection results relating to a power transmission device and a power reception device, a wireless power transmission system is provided with a power transmission device (100) and a power reception device (200). A power transmitting device (100) wirelessly transmits power to a power receiving device (200) by using a power transmitting antenna. The power transmission apparatus (100) performs calibration processing based on measurement of a physical quantity and performs state detection using a measured value. The power transmission device (100) determines whether or not to request re-execution of the calibration process using information acquired when the measurement process is executed by the first state detection and information acquired when the measurement process is executed by the second state detection after the first state detection, and reports the determined information to the power reception device (200).

Description

Technical Field

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

[0002] In a wireless power transmission system, a power transmission device can wirelessly transmit power to a power reception device placed on a charging stand or the like. When it is determined that an abnormal state has occurred, the power transmission device or the power reception device performs control to prevent a decrease in power transmission efficiency and heat generation.

[0003] Patent Document 1 discloses a process for detecting a foreign object that has entered between a power transmission coil and a power reception coil and a process for detecting a positional deviation between the power transmission coil and the power reception coil.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2017-38509 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] In the prior art, a method for using a power transmission device to determine appropriate control based on a plurality of state detection results and report a plurality of pieces of information related to the control to a power reception device has not been established.

[0009] An object of the present disclosure is to provide a technique capable of performing power transmission control and power reception control based on a plurality of state detection results related to a power transmission device and a power reception device.

[0010] Solutions to the Problems

[0011] A power transmission device according to the present disclosure includes: a power transmission unit configured to wirelessly transmit power to a power reception device using a power transmission antenna; a communication unit configured to communicate with the power reception device; a detection unit configured to perform a measurement process for a physical quantity related to the power transmission device and perform a state detection of the power transmission device; and a control unit configured to control the power transmission unit and perform control related to the measurement process. When the power reception device determines to request the power transmission device to perform the measurement process again based on information obtained when performing a first state detection based on the measurement process and information obtained when performing a second state detection based on a measurement process performed after the measurement process, the control unit performs control to use the communication unit to transmit a signal including information related to a state detection result related to the first state detection or the second state detection to the power reception device and a signal including information related to the request to perform the measurement process again.

[0012] Effect of the Invention

[0013] According to the present disclosure, a technology capable of performing power transmission control and power reception control based on a plurality of state detection results related to a power transmission device and a power reception device can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a diagram showing an example of the structure of a wireless power transmission system.

[0015] Figure 2 It is a diagram showing an example of the structure of a power transmission device.

[0016] Figure 3 It is a diagram showing an example of the structure of a power reception device.

[0017] Figure 4 It is an explanatory diagram for explaining an example of a threshold setting method in state detection using the power loss method.

[0018] Figure 5 (A) of Figure 5 (B) of is an explanatory diagram of the Q value measurement method.

[0019] Figure 6 It is a block diagram showing an example of the functional structure of the control unit of the power transmission device.

[0020] Figure 7 It is a flowchart for explaining an example of the processing of the power transmission device.

[0021] Figure 8 It is a flowchart for explaining an example of the processing of the power reception device.

[0022] Figure 9 It is an explanatory diagram of state detection by the waveform attenuation method.

[0023] Figure 10 It is a diagram showing an example of the processing for wirelessly transmitting power.

[0024] Figure 11 It is an explanatory diagram showing an example of a threshold setting method in state detection by the waveform attenuation method.

[0025] Figure 12 (A) of Figure 12 (B) of is an explanatory diagram showing an example of a method for measuring the coupling state index of a power transmission antenna and a power reception antenna.

[0026] Figure 13 It is an explanatory diagram showing an example of a threshold setting method in state detection by the coupling state index measurement method.

[0027] Figure 14 It is a flowchart showing an example of the process of the power transmission device in the second embodiment.

[0028] Figure 15 It is a flowchart showing an example of the process of the power receiving device in the second embodiment.

[0029] Figure 16 It is a sequence diagram showing an example of the processes of the power transmission device and the power receiving device.

[0030] Figure 17 It is a flowchart showing an example of the process of the power transmission device in the third embodiment.

[0031] Figure 18 It is used to illustrate Figure 17 The flowchart of the example of the subsequent process.

[0032] Figure 19 It is a sequence diagram showing an example of the processes of the power transmission device and the power receiving device in the third embodiment. Detailed Description of the Embodiment

[0033] The present disclosure will be described in detail below with reference to the accompanying drawings. In the embodiment, a wireless charging system to which a wireless power transmission system is applied is shown. As an example, wireless power transmission based on a standard (hereinafter referred to as the "WPC standard") established by the Wireless Power Consortium, which is a standardization organization for wireless charging, will be described.

[0034] [First Embodiment]

[0035] It will be described with reference to Figures 1 to 13 to explain the embodiment. Figure 1 It is a diagram showing an example of the structure of the wireless charging system.

[0036] The system includes a power transmission device 100, a power receiving device 200, and a charging station 300. In the following description, for simplicity of notation, in some cases, the power receiving device 200 may be referred to as "RX", and the power transmission device 100 may be referred to as "TX". The detailed structures of TX and RX will be described later with reference to Figure 2 and Figure 3 to explain the detailed structures of TX and RX.

[0037] RX is an electronic device that receives power from TX and charges its built-in battery while being placed on the charging stand 300. TX is an electronic device that wirelessly transmits power to RX placed on the charging stand 300.

[0038] Since the charging stand 300 forms part of the TX, hereinafter, when the RX is "placed on the charging stand 300", in some cases, this can be considered that the RX is "placed on the TX". The spatial range within which the RX can receive power from the TX is schematically shown by the range of the dashed box 400 in Figure 1 as follows.

[0039] The RX and TX may have functions for performing applications other than the wireless charging function. For example, the RX is a smart phone and the TX is an accessory device for charging the battery of the RX. Here, the present invention is not limited to this example.

[0040] An example of the structure of the power transmission device 100 will be described below with reference to Figure 2 as follows. Figure 2 FIG. is a functional block diagram showing an example of the structure of the power transmission device 100 (TX). The 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 resonance capacitor 107, a switch unit 108, a second communication unit 109, and a user interface unit 110.

[0041] Hereinafter, the user interface is abbreviated as "UI". Although each functional block element is referred to as a separate entity in Figure 2 the same, any plurality of functional block elements may be implemented on the same chip.

[0042] The control unit 101 controls the entire TX by executing the control program stored in the memory 106. In addition, the control unit 101 performs power transmission control including communication for device authentication in the TX.

[0043] In addition, the control unit 101 may perform control for executing applications other than wireless power transmission. The control unit 101 includes one or more processors such as a central processing unit (CPU) or a microprocessor unit (MPU).

[0044] Alternatively, the control unit 101 may be constituted by hardware such as an application specific integrated circuit (ASIC).

[0045] In addition, the control unit 101 may be configured to include an array circuit such as a field programmable gate array (FPGA) that is compiled to execute a predetermined process. The control unit 101 may perform a process of storing information to be stored in the memory 106 during the execution of various processes and a time measurement process using a timer (not shown).

[0046] The power supply unit 102 supplies power to each functional block element. The power supply unit 102 includes, for example, a power connection circuit to a commercial power supply and a battery. The battery is charged using the power supplied from the commercial power supply.

[0047] The power transmission unit 103 converts the DC (direct current) power or AC (alternating current) power input from the power supply unit 102 into AC power in a frequency band for wireless power transmission, and inputs this AC power to the power transmission antenna 105, thereby generating electromagnetic waves to be received by the RX.

[0048] For example, the power transmission unit 103 includes an inverter and uses a switching circuit having a half-bridge or full-bridge structure to convert the DC voltage supplied by the power supply unit 102 into an AC voltage. The power transmission unit 103 includes a plurality of field effect transistors (FETs) forming a bridge and a gate driver for controlling the ON / OFF (turn-on / turn-off) of the plurality of field effect transistors.

[0049] The power transmission unit 103 controls the intensity of the electromagnetic waves (transmitted power) to be output by adjusting the voltage (transmission voltage) or current (transmission current) or both the voltage and current input to the power transmission antenna 105.

[0050] The intensity of the electromagnetic waves (intensity of the transmitted power) is controlled using the amount of the transmission voltage or transmission current. Alternatively, the power transmission unit 103 controls the intensity of the electromagnetic waves (transmitted power) to be output by adjusting the voltage or current or both the voltage and current input to the inverter owned by the power transmission unit 103. The voltage input to the inverter is hereinafter referred to as the "inverter input voltage".

[0051] In addition, the current input to the inverter is hereinafter referred to as the "inverter input current". The intensity of the electromagnetic waves is controlled using the amount of the inverter input voltage or inverter input current. Alternatively, the power transmission unit 103 controls the intensity of the electromagnetic waves (transmitted power) to be output by adjusting the voltage or current or both the voltage and current output from the inverter owned by the power transmission unit 103.

[0052] The voltage output from the inverter is hereinafter referred to as the "inverter output voltage". Further, the current output from the inverter is hereinafter referred to as the "inverter output current". The intensity of the electromagnetic waves is controlled using the amount of the inverter output voltage or inverter output current.

[0053] The power transmission unit 103 performs output control of the power of the AC frequency electromagnetic waves based on an instruction signal from the control unit 101, such as starting or stopping the power transmission using the power transmission antenna 105, or controlling the intensity of the electromagnetic waves to be output.

[0054] In addition, it is assumed that the power transmission unit 103 has a power supply capacity sufficient to output 15 watts (W) of power to the charging unit ( Figure 3 reference numeral 206 in

[0055] ) of the power receiving device 200 compliant with the WPC standard.

[0056] The first communication unit 104 is connected to the control unit 101 and the power transmission unit 103, and performs communication for power transmission control based on the WPC standard between the first communication unit 104 and the RX. The first communication unit 104 performs frequency shift keying of the electromagnetic wave output from the power transmission antenna 105 and sends information to the RX to perform communication.

[0057] In addition to storing the control program, the memory 106 can also store information related to the states of the TX and the RX. Information related to the states of the TX and the RX includes the power transmission power value, the power reception power value, and the like.

[0058] Information related to the state of the TX is obtained using the control unit 101. Information related to the state of the RX can be obtained using the RX control unit ( Figure 3 reference numeral 201 in

[0059] ), and can be received using the first communication unit 104 or the second communication unit 109 to be described later.

[0060] 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 sends a control signal to the switch unit 108 to perform its ON / OFF control.

[0061] The power transmission antenna 105 is connected to the resonance capacitor 107. When the switch unit 108 is turned on and short-circuited using the control signal from the control unit 101, the power transmission antenna 105 and the resonance capacitor 107 form a series resonance circuit and resonate at a specific frequency fA.

[0062] The second communication unit 109 is connected to the control unit 101 and performs communication between the second communication unit 109 and the RX using a standard different from the WPC standard. For example, the second communication unit 109 uses an antenna different from the power transmission antenna 105 to communicate with the RX ( Figure 3 the second communication unit 212 in

[0063] ). Wireless Local Area Network (LAN), Bluetooth (registered trademark) Low Energy (BLE), and Near Field Communication (NFC) are provided as examples.

[0064] The frequency band used for power transmission from the power transmission antenna 105 is different from the frequency band used by the second communication unit 109 for communication.

[0065] Regarding communication between the TX and the RX, the TX can selectively use any one of multiple communication standards to communicate with the RX. It is possible to selectively utilize the communication forms of multiple communications to be shown below.

[0066] · Communication based on the first standard (WPC standard) performed between the first communication unit 104 of the TX and the first communication unit 204 of the RX ( Figure 3 ).

[0067] ·· Communication based on the second standard (a standard other than the WPC standard) performed between the second communication unit 109 of the TX and the second communication unit 212 of the RX ( Figure 3 ).

[0068] The user interface (UI) unit 110 is connected to the control unit 101 and performs various outputs to the user. Various outputs include screen display, blinking or color change of a light-emitting diode (LED), audio output through a speaker, and vibration of the TX body, etc. The UI unit 110 is implemented using a liquid crystal panel, a speaker, a vibration motor, etc.

[0069] Examples of the structure of the power receiving device 200 will be described below with reference to Figure 3 . Figure 3 is a block diagram showing an example of the structure of the power receiving device 200 (RX). The RX has 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.

[0070] 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. Although the functional block elements in this embodiment show Figure 3 examples of separate elements, multiple functional block elements can be implemented as one hardware module.

[0071] The control unit 201 controls each functional block element of the RX by executing the control program stored in the memory 208. In addition, the control unit 201 can execute control for applications other than wireless power transmission.

[0072] The control unit 201 includes one or more processors such as a CPU or an MPU. In addition, the control unit 201 can control the entire RX (e.g., the entire smart phone) in cooperation with the operating system (OS) that is running.

[0073] Alternatively, the control unit 201 may be constituted by hardware such as an ASIC, or may include an array circuit such as an FPGA that is compiled to execute a predetermined process. The control unit 201 stores information to be stored during the execution of various processes in the memory 208, and is also capable of executing time measurement processing using a timer (not shown).

[0074] The UI unit 202 is connected to the control unit 201 and performs various outputs to the user. Various outputs include screen display, blinking or color change of an LED, audio output through a speaker, and vibration of the RX main body, etc. The UI unit 202 is implemented using a liquid crystal panel, a speaker, a vibration motor, etc.

[0075] The power receiving unit 203 receives AC power (AC voltage and AC current) generated by electromagnetic induction based on the electromagnetic wave radiated from the power transmitting antenna 105 of the TX via the power receiving antenna (power receiving coil) 205.

[0076] In addition, the power receiving unit 203 converts the AC power into direct current (DC) or AC power of a predetermined frequency, and supplies power to the charging unit 206. The charging unit 206 charges the battery 207. The power receiving unit 203 includes a rectifying unit (rectifier, rectifying circuit) and a voltage control unit required to supply power to loads in the RX.

[0077] The rectifying unit converts the AC voltage and AC current received from the power transmitting antenna 105 via the power receiving antenna 205 into a DC voltage and a DC current. This DC voltage is hereinafter referred to as the "rectifying unit output voltage".

[0078] In addition, this DC current is hereinafter referred to as the "rectifying unit output current". The voltage control unit converts the level of the rectifying unit output voltage into a predetermined level. The predetermined level is a DC voltage level at which the control unit 201 or the charging unit 206 etc. can operate.

[0079] The power receiving unit 203 supplies power for charging the battery 207 from the charging unit 206. It is assumed that the power receiving unit 203 has a power supply capacity sufficient to output 15 watts of power to the charging unit 206.

[0080] The first communication unit 204 performs communication for power receiving control based on the WPC standard between the first communication unit 204 and the first communication unit 104 owned by the TX. The first communication unit 204 is connected to the power receiving antenna 205 and the control unit 201, and demodulates the electromagnetic wave input from the power receiving antenna 205 to obtain the information transmitted from the TX.

[0081] The first communication unit 204 performs load modulation or amplitude modulation on the input electromagnetic wave, and superimposes a signal related to the information to be transmitted to the TX on the electromagnetic wave, thereby performing communication between the first communication unit 204 and the TX.

[0082] The memory 208 stores information related to the states of the TX and RX, etc., in addition to storing control programs. The information related to the state of the RX is obtained using the control unit 201. The information related to the state of the TX is obtained using the control unit 101 of the TX, and can be received using the first communication unit 204 or the second communication unit 212.

[0083] The second communication unit 212 is connected to the control unit 201, and performs communication between the second communication unit 212 and the TX using a standard different from the WPC standard. For example, the second communication unit 212 uses an antenna different from the power receiving antenna 205 to communicate with the second communication unit 109 in the TX Figure 2 ).

[0084] The standard other than the WPC standard is as described above, and regarding the communication between the TX and the RX, the RX can selectively use any one of the multiple communication standards to perform communication between the RX and the TX.

[0085] The frequency band used when receiving power using the power receiving antenna 205 is different from the frequency band used by the second communication unit 212 for communication.

[0086] The first switch unit 209 is provided between the charging unit 206 and the battery 207, and is controlled using the control unit 201. The first switch unit 209 has a function of controlling whether the power received by the power receiving unit 203 is to be supplied to the battery 207 and a function of controlling the amount of the load.

[0087] When the control unit 201 is used to turn off the first switch unit 209 so that the circuit is in an open state, the power received by the power receiving unit 203 is not supplied to the battery 207. When the control unit 201 is used to turn on the first switch unit 209 so that the circuit is short-circuited, the power received by the power receiving unit 203 is supplied to the battery 207.

[0088] Although in the Figure 3 example, the first switch unit 209 is arranged between the charging unit 206 and the battery 207, the first switch unit 209 can be arranged between the power receiving unit 203 and the charging unit 206.

[0089] Alternatively, the first switch unit 209 can be arranged between the power receiving unit 203 and the closed circuit formed by the power receiving antenna 205, the resonant capacitor 211, and the second switch unit 210. In this case, the first switch unit 209 has the function of controlling whether the power received by the power receiving antenna 205 is supplied to the power receiving unit 203.

[0090] In addition, although in the Figure 3 example, the first switch unit 209 is referred to as a functional block element, the first switch unit 209 can be implemented as part of the charging unit 206 or the power receiving unit 203.

[0091] Furthermore, the first switch unit 209 is not limited to the structure in which the first switch unit 209 is inserted in series between the charging unit 206 and the battery 207, and can be inserted in parallel between the charging unit 206 and the battery 207.

[0092] In this case, when the control unit 201 is used to turn off the first switch unit 209 so that the circuit is in an open state, the power received by the power receiving unit 203 is supplied to the battery 207. When the control unit 201 is used to turn on the first switch unit 209 so that the circuit is short-circuited, the power received by the power receiving unit 203 is not supplied to the battery 207.

[0093] On the input side of the power receiving unit 203, the second switch unit 210 is connected in parallel to the resonant capacitor 211. The resonant capacitor 211 is connected to the power receiving antenna 205 via the third switch unit 213.

[0094] The control unit 201 is used to control the second switch unit 210 and the third switch unit 213. The third switch unit 213 has the function of controlling whether the terminal of the power receiving antenna 205 is in an open state.

[0095] When using the control unit 201 to turn off the third switching unit 213, the terminals of the power receiving antenna 205 are in an open state. When using the control unit 201 to turn on the third switching unit 213, the power receiving antenna 205 is connected to the power receiving unit 203 via the resonance capacitor 211.

[0096] When using the control unit 201 to turn on the third switching unit 213 and turn on the second switching unit 210 to short - circuit the circuit, the power receiving antenna 205 and the resonance capacitor 211 form a series resonance circuit and resonate at a specific frequency fB.

[0097] Current flows through the closed circuit formed by the power receiving antenna 205, the resonance capacitor 211, and the second switching unit 210, and the current does not flow through the power receiving unit 203. In addition, if the second switching unit 210 is turned off and the circuit is in an open state, the power received by the power receiving antenna 205 and the resonance capacitor 211 is supplied to the power receiving unit 203.

[0098] The present invention is not limited to Figure 3 the examples, and the second switching unit 210 may be arranged between the power receiving antenna 205 and the resonance capacitor 211. When the third switching unit 213 is turned on and the second switching unit 210 is turned on, the terminals of the power receiving antenna 205 are short - circuited. In addition, the third switching unit 213 may be arranged between the resonance capacitor 211 and the power receiving unit 203.

[0099] In this system, wireless power transfer based on the WPC standard is performed between the power transmitting antenna 105 and the power receiving antenna 205. In the WPC standard, the amount of electric power guaranteed when the power receiving device 200 receives power from the power transmitting device 100 is specified by the electric power called guaranteed load power (hereinafter referred to as "GP").

[0100] The value of GP is expressed as a GP value or GP. For example, GP indicates the following power value: even if the coupling between the power receiving antenna 205 and the power transmitting antenna 105 weakens due to a change in the positional relationship between the power receiving device 200 and the power transmitting device 100 and the power transmission efficiency decreases, this power value can guarantee the output of the power receiving device 200 to the load.

[0101] The load of the power receiving device 200 is Figure 3 the charging unit 206 or the battery 207, etc. in, and the GP value corresponds to the amount of electric power guaranteed to be output from the power receiving unit 203. Alternatively, the GP value corresponds to the amount of electric power guaranteed to be output from the rectifying unit owned by the power receiving unit 203.

[0102] For example, assume that the GP value is 5 watts (W) and the positional relationship between the power receiving antenna 205 and the power transmitting antenna 105 changes. In this case, even if the power transmission efficiency decreases, the power transmission device 100 performs power transmission control so that 5 watts can be output to the load of the power receiving device 200.

[0103] In addition, GP is determined through negotiation performed between the power transmission device 100 and the power receiving device 200. This embodiment can be applied not only to GP, but also to the following configuration: power transmission and reception are performed using the power determined through negotiation between the power transmission device and the power receiving device.

[0104] In addition, assume that when power is transmitted from the power transmission device 100 to the power receiving device 200, there is an object near the power transmission device 100. The object in this case is an object that can affect the power transmission from the power transmission device 100 to the power receiving device 200, and is a foreign object different from the power receiving device 200. The electromagnetic wave used for power transmission can affect the foreign object, potentially causing these foreign objects to heat up or even be damaged.

[0105] Foreign objects in the present disclosure are, for example, paper clips and IC cards. A foreign object is an object that is neither part of the power receiving device or a product incorporating the power receiving device, nor part of the power transmission device or a product incorporating the power transmission device, and may generate heat when exposed to the power signal transmitted by the power transmission antenna.

[0106] The power receiving device and an object that is an essential part of a product incorporating the power receiving device, and the power transmission device and an object that is an essential part of a product incorporating the power transmission device are not foreign objects.

[0107] The WPC standard stipulates a method for suppressing the temperature rise and damage of foreign objects by stopping power transmission when foreign objects are present. Specifically, the power transmission device 100 can detect the presence of foreign objects on the charging stand 300.

[0108] The power loss method is a method for detecting foreign objects based on the difference between the power transmitted in the power transmission device 100 and the power received in the power receiving device 200. The Q - value measurement method is a method for detecting foreign objects based on the change in the quality factor (Q - factor, quality coefficient, Q - value) of the power transmission antenna 105 (power transmission coil) in the power transmission device 100.

[0109] In addition, the Q - value measurement method is a method for detecting foreign objects by detecting the change in the quality factor (Q - factor, quality coefficient, Q - value) of the resonant circuit including the power transmission antenna 105 (power transmission coil) and the resonant capacitor 107 in the power transmission device 100.

[0110] Here, the foreign object detected by the power transmission device 100 is not limited to the object present on the charging stand 300. The power transmission device 100 can detect a foreign object located near the power transmission device 100.

[0111] For example, the power transmission device 100 can detect a foreign object within the range where power transmission can be performed. Hereinafter, the quality factor of the power transmission antenna 105 and the quality factor of the resonance circuit including the power transmission antenna 105 and the resonance capacitor 107 will be referred to as the "quality factor related to the power transmission antenna 105".

[0112] Reference will be made to Figure 4 to explain the foreign object detection based on the power loss method defined in the WPC standard. In Figure 4 the horizontal axis represents the power transmitted by the power transmission device 100, and the vertical axis represents the power received by the power receiving device 200.

[0113] On the graph line represented by the straight line segment 1002, the point 1000 corresponds to the first power transmission value Pt1 and the first power reception value Pr1, and the point 1001 corresponds to the second power transmission value Pt2 and the second power reception value Pr2. On this graph line, the point 1003 corresponds to the third power transmission value Pt3 and the third power reception value Pr3. The foreign object to be detected is a conductive metal sheet or the like.

[0114] First, the power transmission device 100 transmits power to the power receiving device 200 at the first power transmission value Pt1, and the power receiving device 200 receives power at the first power reception value Pr1. Hereinafter, this state will be referred to as the "Light Load state".

[0115] The power transmission device 100 stores the first power transmission value Pt1. At this time, the power receiving device 200 performs load control so that the received power is the minimum power. Alternatively, the power receiving device 200 performs load control so that the received power is within a predetermined range that has been previously determined, or is power equal to or less than a threshold value.

[0116] Here, in the "power within a predetermined range that has been previously determined" or "power equal to or less than a threshold value", the "power" refers to power that is approximately 10% of the reference power described below.

[0117] In addition, the power receiving device 200 can disconnect the load from the power receiving antenna 205 so that the received power is not supplied to the load (such as Figure 3 the charging unit 206 and the battery 207 in). Alternatively, the power receiving device 200 can control the load so that a predetermined power is supplied to the load.

[0118] These can be achieved by controlling the first switching unit 209. Subsequently, the power receiving device 200 reports the first received power value Pr1 to the power transmitting device 100. The power transmitting device 100 receives a signal related to the first received power value Pr1 from the power receiving device 200, and calculates the power loss between the power transmitting device 100 and the power receiving device 200.

[0119] The power loss at this time is Pt1 - Pr1 (= Ploss1). A calibration point (hereinafter abbreviated as "CP") 1000 for indicating the correspondence between Pt1 and Pr1 can be generated.

[0120] Subsequently, the power transmitting device 100 changes the power transmission value to a second power transmission value Pt2 and transmits power to the power receiving device 200, and the power receiving device 200 receives power with the second received power value Pr2. Hereinafter, this state will be referred to as the "Connected Load state (load connection state)".

[0121] The power transmitting device 100 stores the second power transmission value Pt2. At this time, the power receiving device 200 performs load control so that the received power is the maximum power. Here, the "maximum power" is the power whose value is close to the reference power to be described later.

[0122] Alternatively, the power receiving device 200 performs load control so that the received power is the power within a predetermined range that has been previously determined, or the power equal to or greater than the threshold value. 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.

[0123] These can be achieved by controlling the first switching unit 209. Subsequently, the power receiving device 200 reports the second received power value Pr2 to the power transmitting device 100. The power transmitting device 100 receives a signal related to the second received power value Pr2 from the power receiving device 200, and calculates the power loss between the power transmitting device 100 and the power receiving device 200.

[0124] The power loss at this time is Pt2 - Pr2 (= Ploss2). A CP 1001 for indicating the correspondence between Pt2 and Pr2 can be generated.

[0125] 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 shows the relationship between the transmitted power and the received power in a state where it is detected that there is no foreign object near the power transmitting device 100 and the power receiving device 200 (hereinafter referred to as the "first detection state").

[0126] When the power transmission device 100 transmits power at a predetermined transmission power in the first detection state based on the line segment 1002, the power reception device 200 can estimate the value of the received power. For example, assume that the power transmission device 100 transmits power at the third transmission power value Pt3. In this case, the power transmission device 100 can estimate the third received power value Pr3 received by the power reception device 200 based on the point 1003 corresponding to Pt3 on the line segment 1002.

[0127] As described above, the power loss between the power transmission device 100 and the power reception device 200 corresponding to the load can be obtained based on a plurality of combinations of the transmission power value of the power transmission device 100 and the received power value of the power reception device 200 measured while changing the load.

[0128] In addition, the power loss between the power transmission device 100 and the power reception device 200 corresponding to all loads can be estimated by interpolation processing using a plurality of combinations of the transmission power value and the received power value. In this way, the calibration process performed by the power transmission device 100 and the power reception device 200 to enable the power transmission device 100 to obtain a combination of the transmission power value and the received power value is referred to as the "calibration process of the power loss method".

[0129] In addition, the calibration process is abbreviated as "CAL process". The power transmission device 100 and the power reception device 200 can perform the CAL process multiple times. After the CAL process has been performed once, the CAL process performed again is hereinafter referred to as the "recalibration process of the power loss method". The recalibration process is also abbreviated as "RECAL process".

[0130] Assume that: after the CAL process of the power loss method, the power transmission device 100 actually transmits power to the power reception device 200 at the third transmission power value Pt3, and the power transmission device 100 receives a signal related to the received power value Pr3* from the power reception device 200.

[0131] Although the signal related to the received power value Pr3* is a received power data packet (mode0 (mode 0)) defined in the WPC standard, other messages can also be used.

[0132] Hereinafter, the received power data packet (mode0) is denoted as RP0. RP0 includes the value of the received power value Pr3*. The power transmission device 100 subtracts the received power value Pr3* received from the power reception device 200 from the received power value Pr3 in the first detection state to calculate Pr3 - Pr3* (= Ploss_FO).

[0133] Ploss_FO can be estimated as the power consumed by a foreign object, that is, the power loss when a foreign object exists near the power transmission device 100 and the power reception device 200. Hereinafter, the state where a foreign object is detected as existing near the power transmission device 100 and the power reception device 200 will be referred to as the "second detection state".

[0134] In the second detection state, the power transmission device 100 compares the power loss Ploss_FO that the foreign object will consume with a predetermined threshold value. If the value of the power loss Ploss_FO exceeds the threshold value, the power transmission device 100 can evaluate that a foreign object exists.

[0135] Alternatively, the power transmission device 100 obtains the third received power value Pr3 in the first detection state from the power reception device 200, and pre-calculates the power loss Pt3 - Pr3 (= Ploss3) between the power transmission device 100 and the power reception device 200.

[0136] Subsequently, the power transmission device 100 obtains the received power value Pr3* from the power reception device 200 in the second detection state, and calculates the power loss Pt3 - Pr3* (= Ploss3*) between the power transmission device 100 and the power reception device 200 in the second detection state.

[0137] In addition, the power transmission device 100 can use Ploss3* - Ploss3 to estimate the power loss Ploss_FO.

[0138] As described above, there are two methods for calculating Ploss_FO in the second detection state.

[0139] · The first method for calculating Ploss_FO based on Pr3 - Pr3*.

[0140] · The second method for calculating Ploss_FO based on Ploss3* - Ploss3.

[0141] Although the second method is basically described in this embodiment, the details of this embodiment also apply to the first method.

[0142] The following will refer to Figure 5 to illustrate the foreign object detection based on the Q value measurement method defined in the WPC standard. Figure 5 The (A) of is a schematic circuit diagram for explaining a method for measuring the quality factor (Q factor, quality coefficient, Q value) using the Q value measurement method.

[0143] The AC power supply 901 is a power supply that outputs the AC power generated by the power transmission unit 103 of TX. The power transmission antenna 902 corresponds to the power transmission antenna 105, and the capacitor 903 corresponds to the resonant capacitor 107.

[0144] The power transmission antenna 902 and the capacitor 903 are connected in series. The voltage value V8 is the voltage value of a predetermined frequency generated by the power transmission unit 103 for operating the wireless power transmission system. The voltage value V9 is the voltage value applied to the power transmission antenna 902.

[0145] Here, it is assumed that the TX can change the frequency related to the voltage value. In addition, the voltage values V8 and V9 are the voltage values measured by the TX when the TX sends an analog Ping (hereinafter referred to as "AP") or a digital Ping (hereinafter referred to as "DP") to the RX.

[0146] Since the voltage values V8 and V9 are AC voltage values, their root mean square (RMS) values can be used.

[0147] Figure 5 (B) shows an example of the characteristic having a peak at 100 kHz as the measurement result of V9 / V8 with respect to the frequency. The horizontal axis is the frequency axis, and the vertical axis represents the voltage ratio "V9 / V8". V9 / V8 represents the quality factor related to the power transmission antenna 902.

[0148] Since V9 / V8 corresponds to the quality factor of the resonant circuit including the power transmission antenna 902 and the resonant capacitor 903, its value changes if an object is placed near the power transmission antenna 902.

[0149] The change in the quality factor is different according to the situation where no object is placed on the TX, the situation where the RX is placed on the TX, the situation where a foreign object (such as a metal sheet, etc.) is placed on the TX, or the situation where the RX and a foreign object are placed on the TX.

[0150] In the negotiation phase, the TX receives the FOD status data packet signal from the RX. The FOD status data packet includes a reference quality factor value and a reference resonant frequency value.

[0151] The reference quality factor value is the quality factor that can be measured at the terminals of the power transmission antenna of the test TX when the RX is installed in the test TX and there is no foreign object nearby.

[0152] In addition, the reference resonant frequency value is the resonant frequency calculated based on the inductance value that can be measured at the terminals of the power transmission antenna of the test TX when the RX is placed on the test TX and there is no foreign object nearby.

[0153] In the Q value measurement method, a threshold is set based on the reference quality factor value. Foreign object detection is performed by comparing this threshold with the quality factor obtained from the measured V9 / V8.

[0154] Alternatively, a threshold is set based on the reference resonant frequency value. Foreign object detection is performed by comparing this threshold with the resonant frequency obtained by measuring V9 / V8.

[0155] The RX and TX in this embodiment perform communication for power transmission and reception control based on the WPC standard. The WPC standard defines multiple stages, which include a power transfer stage for performing power transmission and one or more stages before performing power transmission.

[0156] In each stage, communication for performing necessary power transmission and reception control is executed. For example, foreign object detection using the power loss method is performed in the power transfer stage based on the data obtained in the calibration stage. In addition, foreign object detection using the Q value measurement method is performed before performing power transmission (before DP transmission and in the negotiation stage or re - negotiation stage).

[0157] The stages before performing power transmission in the WPC standard include a selection stage, a Ping stage, and an identification and configuration stage (configuration stage).

[0158] In addition, there are a negotiation stage and a calibration stage. Hereinafter, the identification and configuration stage will be referred to as the "I&C stage". The processing of each stage will be described below.

[0159] In the selection stage, the TX intermittently transmits an AP and detects that an object has been placed on the charging stand of the TX. For example, the TX detects that an RX or a conductor sheet, etc. has been placed on the charging stand. The TX detects the voltage value or current value or both the voltage value and current value of the power transmission antenna 105 when the AP has been transmitted.

[0160] When the voltage value drops below a threshold or when the current value exceeds a threshold, the TX determines that an object exists and performs a transition to the Ping stage. Alternatively, when the quality factor obtained from the voltage value or current value satisfies a specified condition, the TX determines that an object exists and performs a transition to the Ping stage.

[0161] In the Ping stage, the TX transmits a DP with higher power than the AP. The power of the DP is sufficient to start the control unit of the RX placed on the TX. The RX reports the received power voltage value to the TX.

[0162] In this way, the TX identifies that the object detected in the selection stage is an RX by receiving a response from the RX that has received the DP. If the TX receives a report of the received power voltage value from the RX, the TX transitions to the I&C stage. In addition, before transmitting the DP, the TX measures, for example, the quality factor related to the power transmission antenna 105 using the AP.

[0163] This measurement result is used when performing the foreign object detection process using the Q value measurement method. Depending on the version of the WPC standard, the above - mentioned selection stage may be included as part of the above - mentioned Ping stage and may also be referred to as the "Ping stage" in some cases.

[0164] In the I&C phase, the TX identifies the RX and obtains device configuration information (capability information) from the RX. The RX transmits signals of an ID data packet and a configuration data packet.

[0165] The ID data packet includes identifier information of the RX, and the configuration data packet includes the device configuration information (capability information) of the RX. The TX that has received the signals of the ID data packet and the configuration data packet responds with an acknowledgment (positive response ACK).

[0166] In addition, the I&C phase ends. Depending on the version of the WPC standard, the I&C phase may also be referred to as the configuration phase in some cases. In the negotiation phase, the GP value is determined based on the GP value requested by the RX or the power transmission capability of the TX, etc.

[0167] In addition, the TX receives a FOD status data packet from the RX, and the FOD status data packet includes the above-mentioned reference quality factor value and reference resonance frequency value.

[0168] In the Q-value measurement method, the presence or absence of a foreign object is evaluated based on a threshold value based on the reference quality factor value and the reference resonance frequency value.

[0169] The TX performs foreign object detection processing using the Q-value measurement method according to a request from the RX. In addition, the WPC standard stipulates the following method, which is to transition to the power transmission phase once and then perform the same processing as the negotiation phase again according to a request from the RX. The phase in which these processes are performed after transitioning from the power transmission phase is called the re-negotiation phase.

[0170] In the calibration phase, the CAL process of the power loss method is performed. In addition, the RX reports a predetermined received power value to the TX, and the TX performs adjustment for efficiently transmitting power.

[0171] The predetermined received power value is, for example, the received power value in a light load state (light load state) or a load connection state (connected load state). The received power value reported to the TX is used for foreign object detection processing using the power loss method.

[0172] In the power transmission phase, the TX and the RX control the start and continuation of power transmission, error handling, and the stop of power transmission due to full charge, etc. The TX and the RX perform communication processing for such power transmission and reception control.

[0173] For example, using the power transmission antenna 105 and the power reception antenna 205 used when performing wireless power transmission based on the WPC standard, communication is performed by superimposing a signal on the electromagnetic wave transmitted from the power transmission antenna 105 or the power reception antenna 205. The range in which communication based on the WPC standard can be performed between the TX and the RX is the same as the range in which power transmission by the TX can be performed.

[0174] Depending on the version of the WPC standard, in some cases, the above calibration phase may also be referred to as a power transmission phase as part of the above power transmission phase.

[0175] The following will refer to Figure 6 to illustrate the functions of the control unit of the TX. Figure 6 is a block diagram showing an example of the structure of the functions 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. The communication control unit 301 performs communication control between the TX and the RX based on the WPC standard via the first communication unit 104, or performs communication control between the TX and the RX via the second communication unit 109.

[0176] The power transmission control unit 302 controls the power transmission unit 103 to control power transmission to the RX. The measurement unit 303 measures the waveform attenuation rate described later. In addition, the measurement unit 303 measures the power transmitted to the RX via the power transmission unit 103 and measures the average power transmission per unit time.

[0177] In addition, the measurement unit 303 measures the quality factor related to the power transmission antenna 105. In addition, the measurement unit 303 uses temperature sensors arranged at multiple locations on the power transmission device 100 to measure the temperature. In addition, the measurement unit 303 measures a quantity (e.g., coupling coefficient) representing the electromagnetic coupling state between the power transmission antenna 105 and the power reception antenna 205.

[0178] The setting unit 304 uses the above method to calculate and set the threshold value for foreign object detection in the Q value measurement method and the threshold value for foreign object detection in the power loss method. In addition, the setting unit 304 uses the method described later to set the threshold value for foreign object detection in the waveform attenuation method.

[0179] In addition, the setting unit 304 calculates and sets, for example, the threshold value for foreign object detection or the threshold value for position offset detection between the TX and the RX based on the coupling coefficient between the power transmission antenna 105 and the power reception antenna 205 measured by the measurement unit 303.

[0180] In addition, the setting unit 304 calculates and sets, for example, a threshold value for foreign object detection or a threshold value for position offset detection between the TX and the RX based on the temperature of the power transmission device measured using the measurement unit 303. In addition, the setting unit 304 calculates and sets, for example, a threshold value for foreign object detection or a threshold value for position offset detection between the TX and the RX based on the current value of the power transmission antenna 105 measured using the measurement unit 303.

[0181] The state detection unit 305 performs state detection of the TX and the RX. For example, the state detection unit 305 detects a foreign object existing between the TX and the RX, and detects a position offset between the power transmission antenna 105 and the power reception antenna 205.

[0182] More specifically, state detection processing based on the power loss method, the Q value measurement method, and the waveform attenuation method is possible. In addition, state detection processing based on the temperature measured using the power transmission device 100, the electromagnetic coupling state (e.g., coupling coefficient) between the power transmission antenna 105 and the power reception antenna 205, and the current value of the power transmission antenna 105 measured using the power transmission device 100 is possible.

[0183] The state detection unit 305 may use other methods to perform foreign object detection and detection of the position offset between the power transmission antenna 105 and the power reception antenna 205. For example, in the TX provided with the NFC communication function, the state detection unit 305 uses the opposite device detection function according to the NFC standard to perform state detection processing.

[0184] In addition, the state detection unit 305 can detect the presence or absence of a foreign object and the electromagnetic coupling state between the power transmission antenna and the power reception antenna, and can detect a state change on the TX. For example, the state detection unit 305 can detect an increase or decrease in the number of power reception devices on the TX.

[0185] When the TX performs state detection, the setting unit 304 sets a threshold value as a criterion for evaluating the presence or absence of a foreign object. The state detection is, for example, state detection based on the power loss method, the Q value measurement method, the waveform attenuation method, or state detection based on the temperature measured in the power transmission device 100.

[0186] In addition, the state detection is state detection based on the coupling coefficient between the power transmission antenna 105 and the power reception antenna 205 and state detection based on the current value of the power transmission antenna 105 measured using the power transmission device 100. The setting unit 304 can set an evaluation threshold value required for state detection processing using other methods.

[0187] The state detection unit 305 can perform foreign object detection processing and processing for detecting the position offset between the power transmission antenna 105 and the power reception antenna 205 based on the threshold value set by the usage setting unit 304 and the measurement result of the measurement unit 303.

[0188] For example, the state detection unit 305 can acquire data such as waveform attenuation rate, power transmission power, and quality factor as the measurement result from the measurement unit 303. The state detection unit 305 can acquire data such as the temperature measured in the power transmission device 100, the coupling coefficient between the power transmission antenna 105 and the power reception antenna 205, and the current value of the power transmission antenna 105 measured in the power transmission device 100, as the measurement result of the measurement unit 303.

[0189] by Figure 6 The processing performed by the communication control unit 301, the power transmission control unit 302, the measurement unit 303, the setting unit 304, and the state detection unit 305 shown can be implemented using a program executed by a CPU or the like set in the control unit 101.

[0190] These processes are executed in parallel according to independent programs, and are synchronized among the programs implemented by event processing or the like. Here, two or more of these processes can be incorporated into the processing of a single program.

[0191] An example of the flow of the processing related to the power transmission and reception control performed by the TX and the RX will be described below. Figure 7 It is a flowchart for explaining an example of the processing for power transmission control performed by the TX. This processing is implemented, for example, using a program read from the memory 106 by the control unit 101 of the TX.

[0192] In addition, when the power of the TX is turned on, when the user of the TX inputs an instruction to start the wireless power transmission application, or when the TX is connected to the commercial power supply and receives power, this processing can be executed. In addition, this processing can be started by some other trigger.

[0193] In Figure 7 In S1201, the TX performs the processing of the selection phase and the Ping phase defined by the WPC standard, and waits for the RX to be placed. The TX repeatedly and intermittently sends the AP of the WPC standard, and detects an object existing within the range where power transmission can be performed.

[0194] For example, the TX can detect that the RX or a conductor sheet or the like is placed on the charging stand 300. When the TX detects an object existing within the range where power transmission can be performed, the TX sends the DP.

[0195] When there is a predetermined response to the DP, the TX evaluates that the detected object is the RX and the RX has been placed on the charging stand 300. Here, the "predetermined response" is the signal strength (SIG) data packet sent by the RX.

[0196] This packet includes a signal strength value for indicating the signal strength of the signal (DP) received by the RX. The signal strength value is calculated based on the voltage (rectifier unit output voltage) output by the rectifier unit (rectifier, rectifier circuit) of the power receiving unit 203 measured by the RX.

[0197] Alternatively, the signal strength value is calculated based on the voltage of the open circuit including the power receiving antenna 205 measured by the RX, or the power receiving value measured by the RX, etc. In addition, before transmitting the DP, the TX measures the quality factor related to the power transmitting antenna 105. This measurement result is used when performing the foreign object detection process using the Q value measurement method.

[0198] After detecting the placement of the RX, in S1202, the TX obtains the identification information from the RX through communication in the I&C phase defined by the WPC standard. In the I&C phase, the RX sends an identification packet (ID packet) to the TX.

[0199] The ID packet stores the manufacturer code and the basic device ID as the identification information for each individual RX, and the information that can identify the version of the supported WPC standard.

[0200] In addition, the RX sends a configuration data packet to the TX. The configuration data packet includes the following RX capability information.

[0201] · Information on the version of the WPC standard that the RX can identify.

[0202] · The maximum power value or reference power as the value specifying the maximum power that can be supplied by the RX to the load.

[0203] · Information indicating whether the RX has the negotiation function of the WPC standard.

[0204] · As a parameter used in frequency shift keying which is the communication modulation method used when the TX sends information to the RX.

[0205] When the TX receives the above packet from the RX, the TX sends an affirmative response ACK and the I&C phase ends. The TX can obtain the identification information of the RX by methods other than the communication in the I&C phase of the WPC standard.

[0206] In addition, the identification information for each individual RX may be a wireless power ID. Alternatively, the identification information may be any other identification information capable of identifying an individual RX, such as the Bluetooth (registered trademark) address unique to the second communication unit 212 of the RX (hereinafter referred to as "BD_ADDR").

[0207] BD_ADDR is an 8-byte address used in BLE. BD_ADDR is a public address defined in the BLE standard, which is used, for example, to indicate the manufacturer of the RX or individual identification information of the BLE communication function (the function of the second communication unit 212). BD_ADDR may be a random address.

[0208] Subsequently, in S1203, the TX determines the GP through negotiation between the TX and the RX based on the request from the RX and the power transmission ability of the subject device. In S1203, communication in the negotiation phase of the WPC standard is performed.

[0209] First, the RX reports the requested value of the GP by sending a specific request to the TX. The TX evaluates whether to accept the request based on the power transmission ability of the subject device and other conditions.

[0210] When the TX accepts the request, the TX sends an affirmative response ACK to the RX, and when the TX does not accept the request, the TX sends a negative response NACK or NAK to the RX. The determined value of the GP is the value requested by the RX when the TX accepts the request from the RX.

[0211] When the TX does not accept the request from the RX, the value of the GP is a predetermined value defined by the WPC standard (for example, 5 watts). Alternatively, when the TX obtains information indicating that the RX does not support the negotiation phase (for example, S1302 described later), the TX does not perform communication in the negotiation phase and determines the GP value as a predetermined value. The predetermined value is, for example, a value predefined using the WPC standard (for example, 5 watts).

[0212] In addition, the TX performs foreign object detection processing using the Q-value measurement method according to the request from the RX. The TX receives a FOD status data packet from the RX. This packet includes the above-mentioned reference quality factor value and reference resonance frequency value.

[0213] Then, the TX performs foreign object detection using the Q-value measurement method. This foreign object detection is performed based on the following information.

[0214] · The quality factor and resonance frequency related to the power transmission antenna 105 measured by the TX before sending the DP.

[0215] · Thresholds based on the reference quality factor value and reference resonance frequency value received by the TX from the RX.

[0216] In the foreign object detection process using the Q - value measurement method, in response to a request from the RX to the TX, the value of the quality factor of the power - transmitting antenna 105 measured by the TX before transmitting the DP is compared with the above - mentioned threshold value, and based on the comparison result, the presence or absence of a foreign object and the possibility of its presence are evaluated.

[0217] Subsequently, in S1204, the TX and the RX execute the calibration - phase process (CAL process) of the WPC standard. In the calibration phase, the TX executes the CAL process of the power - loss method based on the determined reference power value or GP value.

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

[0219] In this embodiment, it is assumed that the first reference received - power information is information for indicating 500 milliwatts. Although the first reference received - power information is information included in the received - power data packet (mode1) defined in the WPC standard, other messages can be used.

[0220] Hereinafter, the received - power data packet (mode1) is represented as RP1. The TX evaluates whether to accept the first reference received - power information based on the control - error value included in the control - error (CE) packet received from the RX.

[0221] When the TX accepts the first reference received - power information, the TX sends an affirmative response ACK to the RX. When the TX does not accept the first reference received - power information, the TX sends a negative response NAK to the RX.

[0222] Subsequently, the RX executes a process for sending a signal having information related to the received power in the load - connected state (hereinafter referred to as "second reference received - power information") to the TX. The load - connected state is, for example, a maximum - load state, a load state in which the power - transmitting power value is equal to or greater than the second threshold value, or a load state in which the power received by the RX is at the maximum power.

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

[0224] In this embodiment, it is assumed that the second reference received power information is information indicating 15 watts. Although the second reference received power information is the information included in the received power data packet (mode2) defined in the WPC standard, other messages can be used.

[0225] Hereinafter, the received power data packet (mode2) is denoted as RP2. The TX evaluates whether to accept the second reference received power information based on the control error value included in the control error (CE) packet received from the RX.

[0226] When the TX accepts the second reference received power information, the TX sends an affirmative response ACK to the RX. When the TX does not accept the second reference received power information, the TX sends a negative response NAK to the RX. The TX sends an affirmative response ACK in response to the second reference received power information from the RX and completes the CAL process.

[0227] Through the above CAL process, the TX can calculate the power loss amount between the TX and the RX in the light load state and the load connection state based on the transmitted power value of the TX and the received power values included in the first reference received power information and the second reference received power information.

[0228] In addition, the TX can calculate the power loss amount between the TX and the RX in all the transmitted powers that can be obtained by the TX by performing an interpolation process between multiple power loss amounts. The transmitted power that can be obtained by the TX is, for example, any power within the range from 500 mW to 15 watts of the received power received by the RX in this embodiment.

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

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

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

[0232] That is, the CE packet includes parameter data for adjusting the transmitted power. By repeatedly performing this process, power can be transmitted in an appropriate power in response to a request from the RX almost in real time.

[0233] When the battery 207 is fully charged, the RX sends an End Power Transfer Packet (hereinafter referred to as "EPT packet") to the TX to end the power transfer phase.

[0234] The RX may send an EPT packet for reasons other than full charge. Additionally, if the power transfer phase ends, the TX stops sending power for charging to the RX.

[0235] Furthermore, when the TX fails to receive the next CE packet after t_timeout has elapsed since receiving the last CE packet, the TX determines that the RX has been removed from the charging station 300. In this case, the power transfer phase ends. t_timeout is a value defined by the WPC standard (e.g., 1500 milliseconds).

[0236] The RX may send packets other than CE packets to the TX during the power transfer phase. For example, there is a Charge Status Packet that reports the status of the RX's battery 207 to the TX.

[0237] This packet stores a charge status value for indicating the percentage of charge of the battery 207. If the TX receives the Charge Status Packet, the TX reports the charge status to the user, for example, by displaying text or a graphic based on the charge status value via the UI unit 110.

[0238] Regarding the Charge Status Packet, the TX may receive the Charge Status Packet at any time and may report the Charge Status Packet to the user at any time.

[0239] During the power transfer phase, the TX sends power to the RX and performs foreign object detection processing using the power loss method. For example, through the CAL process, the power loss amount between the TX and the RX in the first detection state during the power transmission process is calculated based on the difference between the power transmission value and the power reception value.

[0240] The calculated power loss amount corresponds to the reference power loss amount in the state where there is no foreign object. Then, when the TX evaluates that the difference between the power loss amount between the TX and the RX measured during the power transmission after the CAL process and the reference power loss amount is equal to or greater than the threshold, the TX determines that the state is in the second detection state.

[0241] For reference Figure 8 An example of the process flow related to the power reception control performed by the RX will be described. This process is implemented, for example, by using a program read from the memory 208 by the control unit 201 of the RX.

[0242] In S1301, the RX performs the processes of the selection phase and the Ping phase defined by the WPC standard, and waits for the self-device to be placed on the TX. The RX detects that the self-device has been placed on the TX, for example, by detecting the DP from the TX.

[0243] If the RX detects that the self-device has been placed on the TX, then in S1302, the RX uses the ID packet and the configuration data packet to send a signal including the identification information of the self-device to the TX.

[0244] The identification information of the RX can be sent by a method other than the communication in the I&C phase of the WPC standard. Additionally, other identification information such as BD_ADDR can be used as long as it is information that can identify each individual of the RX. Additionally, in S1302, the RX can send information other than the identification information to the TX.

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

[0246] The RX sends a FOD status data packet to the TX. This packet includes a reference quality factor value and a reference resonance frequency value.

[0247] Subsequently, in S1304, the RX and the TX perform the WPC standard calibration phase process (CAL process). The process performed by the RX in this phase is as described above. After that, in S1305, the RX receives power until the battery 207 is fully charged.

[0248] In the power transfer phase, the RX and the TX perform foreign object detection processing using the power loss method. In S1305, the RX repeatedly sends CE packets at intervals of t_interval and finally sends an EPT packet to the TX to complete this process.

[0249] As described above, the power loss method is a method for detecting foreign objects based on the measurement result of the power loss amount during power transmission from the TX to the RX. Although this method has the disadvantage that the accuracy of foreign object detection decreases when the TX is sending large power, this method has the advantage that foreign object detection processing can be performed while continuing power transmission, thereby maintaining high power transmission efficiency.

[0250] Incidentally, only through the foreign object detection using the power loss method in the power transfer phase, there may be a possibility of false detection of foreign objects or a possibility of false evaluation that "there is no foreign object" although there is a foreign object.

[0251] For example, assume that there is a foreign object near the TX and RX during power transmission in the power transmission stage. In this case, there is a possibility that the heat generated from the foreign object may increase. Therefore, it is necessary to improve the accuracy of foreign object detection at the end of the power transmission stage.

[0252] Therefore, a foreign object detection method using the waveform attenuation method will be described. Using this method, the TX can perform foreign object detection based on the attenuation state of the power transmission waveform (voltage waveform or current waveform) related to power transmission to the RX. That is, foreign object detection can be performed without using a newly defined foreign object detection signal or the like.

[0253] Figure 9 It is a diagram for explaining the principle of foreign object detection by the waveform attenuation method. An example of foreign object detection using a power transmission waveform related to power transmission from the power transmission device 100 (TX) to the power reception device 200 (RX) is shown. In Figure 9 it, the horizontal axis represents the time axis, and the vertical axis represents the voltage value or current value.

[0254] Figure 9 The waveform 600 shown, for example, shows the change over time of the voltage value of the high-frequency voltage applied to the power transmission antenna 105 of the TX. Alternatively, Figure 9 it shows the change over time of the high-frequency voltage value or current value observed in the circuit of the TX including the power transmission antenna 105 and the resonance capacitor 107.

[0255] The TX that transmits power to the RX via the power transmission antenna 105 stops power transmission at time T0. At time T0, the power supply for power transmission from the power supply unit 102 is stopped, and the power supply for power transmission to the power transmission antenna 105 is stopped.

[0256] The frequency f1 of the power transmission waveform before power transmission is stopped at time T0 is, for example, a fixed frequency between 87 kHz and 205 kHz used in the WPC standard. The point 601 on the waveform 600 is a point on the envelope line of the high-frequency voltage, and (T1, A1) indicates that the voltage value at time T1 is A1.

[0257] The point 602 on the waveform 600 is a point on the envelope line of the high-frequency voltage, and (T2, A2) indicates that the voltage value at time T2 is A2.

[0258] The quality factor (Q factor, Q value) of the resonance circuit including the power transmission antenna 105 and the resonance capacitor 107 can be obtained based on the change over time of the voltage value after time T0.

[0259] For example, based on the times, voltage values, and the frequency f2 of the high-frequency voltage after power transmission is stopped at time T0 at the points 601 and 602 on the envelope line of the high-frequency voltage, the TX calculates the quality factor using Equation 1.

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

[0261] In Equation 1, ln represents the natural logarithm function. The frequency (f1) of the power transmission waveform when TX is transmitting power in the positive direction to RX can be different from the frequency (f2) of the power transmission waveform when TX stops transmitting power to RX.

[0262] Although the value of the quality factor decreases when there is a foreign object near TX and RX, the reason is that the foreign object causes energy loss. Thus, when focusing on the slope of the attenuation of the voltage value, when there is a foreign object, the slope of the line connecting points 601 and 602 is greater than when there is no foreign object.

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

[0264] To actually evaluate the presence or absence of a foreign object, it can be evaluated by comparing a certain value representing the attenuation state. For example, when using the quality factor for evaluation, a quality factor value lower than the reference value means a higher waveform attenuation rate (the degree of reduction of the waveform amplitude per unit time).

[0265] As another example, there is a method for evaluating using the slope of the line connecting points 601 and 602 calculated by (A1 - A2) / (T2 - T1). In addition, when the measurement times (T1 and T2) of the attenuation state of the voltage value are fixed, the difference (A1 - A2) or the ratio (A1 / A2) of the voltage values can be used to evaluate the presence or absence of a foreign object.

[0266] Alternatively, when assuming that the voltage value A1 immediately after power transmission stops is constant, the voltage value A2 after a predetermined time can be used to evaluate the presence or absence of a foreign object. Alternatively, the time (T2 - T1) elapsed until the voltage value A1 reaches a predetermined voltage value A2 can be used to evaluate the presence or absence of a foreign object.

[0267] In the waveform attenuation method, the presence or absence of a foreign object can be evaluated using the attenuation state of the waveform during the power transmission stop period. In the present disclosure, indicators such as the quality factor representing the attenuation state of the power transmission waveform are collectively referred to as the "waveform attenuation rate".

[0268] In addition, although Figure 9 the vertical axis of Figure 9The vertical axis can represent the current value flowing through the power transmission antenna 105. Similar to the case of the voltage value, the attenuation state of the current value during the power transmission stop time period changes according to the presence or absence of a foreign object.

[0269] When a foreign object is present, the waveform attenuation rate is higher than when no foreign object is present. Therefore, a foreign object can be detected by applying the same method as described above to the time variation of the current value flowing through the power transmission antenna 105.

[0270] That is, the quality factor calculated from the current waveform, the slope of the attenuation of the current value, the difference between current values, the ratio of current values, the absolute value of the current value, or the time until the current value reaches a predetermined value, etc. can be used as the waveform attenuation rate to evaluate the presence or absence of a foreign object, and foreign object detection can be performed.

[0271] In addition, there is a method based on both the attenuation state of the voltage value and the attenuation state of the current value. In this method, an evaluation value calculated from the waveform attenuation rate of the voltage value and the waveform attenuation rate of the current value can be used to evaluate the presence or absence of a foreign object.

[0272] Examples of measuring the waveform attenuation rate during the time period when TX temporarily stops power transmission are not limited. The waveform attenuation rate can be measured during the time period when TX temporarily reduces the power supplied from the power supply unit 102 from a predetermined power level to a power level lower than the predetermined power level.

[0273] That is, the waveform attenuation rate can be measured during the time period when the power transmission to the power transmission antenna 105 is temporarily reduced from a predetermined power level to a lower power level. In addition, the power transmission unit 103 can limit the power transmission to the above-mentioned power transmission antenna 105 (stop power transmission or reduce power transmission) based on the command signal from the control unit 101.

[0274] In addition, although the voltage value or current value is measured at two time points during the time period when TX limits power transmission in the above example, the voltage value or current value can be measured at three or more than three time points, and these values can be used to calculate the waveform attenuation rate.

[0275] Reference will be made to Figure 10 to describe the foreign object detection method based on the power transmission waveform using the waveform attenuation method. Figure 10 The shown power transmission waveform is the power transmission waveform when performing foreign object detection using 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 transition response period immediately after power transmission starts at TX, the power transmission waveform is unstable. Thus, during this transition response period, RX controls TX such that communication with TX (communication using amplitude modulation or load modulation) is not performed.

[0277] In addition, TX controls RX such that communication with RX (communication using frequency shift keying) is not performed. Hereinafter, this period is referred to as the communication prohibition period. Here, during the communication prohibition period, TX transmits power to RX.

[0278] In addition, after the communication prohibition period has elapsed, TX transmits power to RX. Thereafter, this period is referred to as the power transmission period. When TX receives a request (packet, command) for performing a foreign object detection operation from RX, TX temporarily stops power transmission or temporarily reduces the power transmission level after a predetermined period has elapsed.

[0279] Thereafter, this predetermined period will be referred to as the "preparation period". During the preparation period, RX controls TX such that communication with TX is not performed by amplitude modulation or load modulation. In addition, TX controls RX such that TX does not perform communication with RX by frequency shift keying.

[0280] By performing control so that communication is not performed during the preparation period, disturbance of the power transmission waveform can be suppressed, and TX can calculate the waveform attenuation rate of the power transmission waveform described later with higher accuracy. The request (packet, command) for performing a foreign object detection operation can be RP0, RP1, or RP2.

[0281] When TX receives an execution request, the power transmission unit 103 temporarily stops power transmission or temporarily reduces the power transmission level so that the amplitude of the power transmission waveform decays. The period from the time point when power transmission is temporarily stopped or the power transmission level is temporarily reduced until the time point when power transmission is restarted again or the power transmission level starts to recover is referred to as the power transmission level control period.

[0282] Here, "restarting power transmission again" means that TX increases the power transmission level to a predetermined value. Alternatively, the period from the time point when TX temporarily sets the value of the inverter input voltage input to the inverter owned by the power transmission unit 103 to 0 V until the time point when TX increases the value of the inverter input voltage to a predetermined value is referred to as the power transmission level control period.

[0283] Alternatively, the period from the time point when TX temporarily reduces the value of the inverter input voltage to a predetermined first voltage value until the time point when TX increases the value of the inverter input voltage to a predetermined second voltage value is referred to as the power transmission level control period.

[0284] Alternatively, the period from the time point when TX temporarily sets the value of the inverter output voltage output by the power transmission unit 103 to 0 V until the time point when TX increases the value of the inverter output voltage to a predetermined voltage value is referred to as the power transmission power control period.

[0285] Alternatively, the period from the time point when TX temporarily reduces the value of the inverter output voltage to a predetermined first voltage value until the time point when TX increases the value of the inverter output voltage to a predetermined second voltage value is referred to as the power transmission power control period.

[0286] In addition, the control for TX to temporarily stop power transmission or temporarily reduce the power transmission power is referred to as power transmission power control. In addition, the control for TX to temporarily set the input voltage or output voltage of the inverter owned by the power transmission unit 103 to 0 V or temporarily reduce its input voltage or output voltage to a predetermined value is referred to as power transmission power control.

[0287] TX calculates the waveform attenuation rate based on the attenuation waveform and compares the calculated waveform attenuation rate with a threshold value to evaluate whether there is a foreign object or the possibility of the presence of a foreign object (probability of presence) (hereinafter also referred to as "foreign object evaluation").

[0288] During the power transmission power control period, RX controls TX so that RX does not communicate with TX using amplitude modulation or load modulation. In addition, TX controls RX so that TX does not communicate with RX using frequency shift keying.

[0289] By performing control not to perform communication during the power transmission power control period, disturbance of the power transmission waveform can be suppressed, and TX can calculate the waveform attenuation rate of the power transmission waveform with higher accuracy. In addition, foreign object evaluation can be performed during the power transmission power control period, communication prohibition period, or power transmission period.

[0290] When no foreign object is detected after the power transmission power control period has elapsed, TX controls to start power transmission again or resume the power transmission power. In the transition response period immediately after the start of this control, the power transmission waveform is unstable, so this period is a communication prohibition period. After that, this period changes to a power transmission period in which stable power transmission is performed from TX to RX.

[0291] As described above, TX repeatedly executes control of the start of power transmission, communication prohibition period, power transmission period, preparation period, and power transmission power control period. TX calculates the waveform attenuation rate based on the attenuation waveform at a predetermined timing and performs foreign object evaluation based on the result of comparing the calculated waveform attenuation rate with a threshold value.

[0292] That is, foreign object evaluation can be performed based on voltage values or current values at two or more time points during a predetermined time period in which power transmission is restricted (including power transmission stop). Additionally, during the preparation time period, the power transmission control time period, and the communication prohibition time period, the RX controls the TX such that the RX does not communicate with the TX through amplitude modulation or load modulation.

[0293] In addition, the TX controls the RX such that the TX does not communicate with the RX through frequency shift keying. That is, the TX controls the RX such that the TX does not communicate with the RX during a predetermined time period (first time period) after receiving an execution request (packet, command) from the RX.

[0294] The WPC standard specifies the following time period during which, after the TX receives a packet other than an execution request from the RX during the power transmission phase, the TX cannot send a packet to the RX (prohibition of packet transmission).

[0295] The first time period is a time period longer than this time period. Additionally, the RX performs control not to communicate with the TX during a predetermined time period (second time period) after sending an execution request (packet, command) to the TX.

[0296] The WPC standard specifies the following time period during which, after the RX sends a packet other than an execution request to the TX during the power transmission phase, the RX cannot send a packet to the TX (prohibition of packet transmission). The second time period is a time period longer than this time period.

[0297] Incidentally, during the power transmission control time period, if components 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 resonant capacitor 211 of the power receiving device 200, the waveform attenuation rate is affected by the load due to these components.

[0298] That is, the value of the waveform attenuation rate changes according to the states of the power receiving unit 203, the charging unit 206, and the battery 207. As a result, even if the value of the waveform attenuation rate is large, it is difficult to distinguish whether this is due to the influence of a foreign object or a change in the states of the power receiving unit 203, the charging unit 206, or the battery 207, etc.

[0299] Therefore, when measuring the waveform attenuation rate and performing foreign object detection, the control unit 201 of the RX turns off the first switch unit 209 during the preparation time period. The RX sends an execution request (packet, command) to the TX and performs the above processing during the preparation time period.

[0300] Alternatively, the RX performs the above processing while sending an execution request packet (command) to the TX. Thus, the influence due to the battery 207 can be suppressed.

[0301] In addition, instead of turning off the first switching unit 209, the same effect can be obtained by setting the first switching unit 209 to a light load state (light load state). In addition, instead of turning off the first switching unit 209, the same effect can be obtained even when the RX performs load control such that the received power is the minimum power.

[0302] Alternatively, instead of turning off the first switching unit 209, the same effect can be obtained even when the RX performs load control such that the received power is within a predetermined range that has been previously determined or is power equal to or less than a threshold value.

[0303] Here, in the "power within a predetermined range that has been previously determined" or "power equal to or less than a threshold value", the "power" refers to power that is approximately 10% of the reference power. Alternatively, instead of turning off the first switching unit 209, the RX can control the load such that a predetermined power is supplied to the load.

[0304] These can be achieved by controlling the first switching unit 209. It is assumed that the above operations are also included as operations in the light load state. The RX maintains the above control even during the power transmission power control period.

[0305] In addition, at the timing after power transmission starts again, the RX releases the above control and performs control to return to the original state. Alternatively, it is assumed that the control unit 201 turns on the second switching unit 210 to short-circuit the circuit, thereby causing current to flow through the closed loop formed by the power receiving antenna 205, the resonance capacitor 211, and the second switching unit 210.

[0306] As a result, the influence on the power receiving unit 203, the charging unit 206, and the battery 207 can be suppressed. The RX sends a foreign object detection execution request (packet, command) to the TX and performs the above processing during the preparation period.

[0307] Alternatively, the RX performs the above processing while sending an execution request (packet, command) to the TX. The RX maintains the above control during the power transmission power control period. In addition, at the timing after power transmission starts again, the RX releases the above control and performs control to return to the original state.

[0308] By obtaining the waveform attenuation rate based on the power transmission waveform measured in the state where the first switching unit 209 is turned off or in the state where the second switching unit 210 is turned on and short-circuited (connected), more accurate foreign object detection can be performed. Alternatively, by performing both turning off the first switching unit 209 and short-circuiting (connecting) the second switching unit 210, more accurate foreign object detection can be performed.

[0309] Alternatively, during the preparation period, in a state where the first switch unit 209 is turned on to short-circuit and the second switch unit 210 is turned off to disconnect, the RX can transition to a low power consumption mode or can perform control so that the power consumption is constant.

[0310] The RX sends an execution request (packet, command) to the TX and performs the above processing during the preparation period. Alternatively, the RX sends an execution request (packet, command) to the TX and performs the above processing simultaneously.

[0311] The RX maintains the above control even during the power supply control period. In addition, at the timing after power supply resumes, the RX releases the above control and performs control to return to the original state. When the power consumption in the RX is not constant or when a large amount of power is consumed, the value of the waveform attenuation rate based on the attenuation waveform is affected by fluctuations in power consumption.

[0312] To suppress this influence, it is effective to restrict or stop the operation of software applications running on the RX, or to set the hardware function blocks included in the RX to a low power consumption mode or an operation stop mode.

[0313] By performing foreign object detection using the waveform attenuation rate based on the power supply waveform measured in a state where the power consumption of the RX is suppressed, more accurate foreign object detection can be performed.

[0314] In addition, similarly, even in the TX, when measuring the waveform attenuation rate, if elements such as the power supply unit 103, the first communication unit 104, and the power supply unit 102 are connected to the power supply antenna 105 and the resonance capacitor 107 of the power supply device 100, the waveform attenuation rate is affected by these elements.

[0315] That is, the value of the waveform attenuation rate changes according to the states of the power supply unit 103, the first communication unit 104, and the power supply unit 102. As a result, for example, even when the value of the waveform attenuation rate is large, it is difficult to distinguish whether the influence is caused by a foreign object or by the power supply unit 103, the first communication unit 104, and the power supply unit 102.

[0316] Thus, when the TX receives an execution request (packet, command) for a foreign object detection operation from the RX, the control unit 101 turns on the switch unit 108 during the preparation period. That is, the control unit 101 sets a state in which current flows into the closed-loop circuit formed by the power supply antenna 105, the resonance capacitor 107, and the switch unit 108.

[0317] Therefore, when measuring the waveform attenuation rate in TX, the influence caused by the power transmission unit 103, the first communication unit 104, and the power supply unit 102 can be suppressed. Alternatively, by providing a switch (not shown) between the power transmission antenna 105 and the power transmission unit 103 and turning off the switch during the preparation period, the influence caused by the power supply unit 102, the power transmission unit 103, and the first communication unit 104 can be suppressed.

[0318] TX maintains the above control even during the power transmission power control period. In addition, at the timing after power transmission is restarted again, TX releases the above control and executes control to return to the original state. Alternatively, a switch can be provided between the power transmission unit 103 and the closed-loop circuit formed by the power transmission antenna 105, the resonant capacitor 107, and the switch unit 108.

[0319] When TX measures the waveform attenuation rate and performs foreign object detection, the above influence can be suppressed by controlling the switch to disconnect the closed-loop circuit and the power transmission unit.

[0320] As described above, at least one of the following states is achieved: the short-circuit (connected) state in which the switch unit 108 is turned on, the disconnected state using the switch between the power transmission antenna 105 and the power transmission unit 103, and the disconnected state using the switch associated with the closed-loop circuit and the power transmission unit 103. This enables more accurate foreign object detection.

[0321] A method for setting a threshold for the waveform attenuation rate for state detection and foreign object evaluation of TX and RX based on the waveform attenuation method will be described below. The measured value of the waveform attenuation rate is compared with the threshold, and foreign object evaluation can be performed based on the comparison result.

[0322] The first threshold setting method is as follows: TX holds a predetermined value that is a common value of RX independent of the transmitted power as the threshold. This threshold is a fixed value or a variable value determined by TX according to the situation.

[0323] If there is a foreign object, the transmitted waveform during the power transmission power control period has a high waveform attenuation rate. Therefore, the value of the waveform attenuation rate obtained in the state where there is no foreign object is held in advance and set as the threshold.

[0324] By comparing the measured value of the waveform attenuation rate with the threshold, it can be evaluated whether "there is a foreign object" or whether "the possibility of having a foreign object is high". For example, when using the quality factor as the waveform attenuation rate, TX compares the measured value of the quality factor with a predetermined threshold.

[0325] The threshold is set based on the measured value in the first detection state or on the value obtained by taking into account the measurement error in the measured value. When the measured value of the quality factor is less than the threshold, it is evaluated as "foreign object present" or "high possibility of foreign object present".

[0326] When the measured value of the quality factor is equal to or greater than the threshold, it is evaluated as "no foreign object present" or "low possibility of foreign object present".

[0327] The second threshold setting method is a method in which the TX adjusts and determines the threshold based on the information sent from the RX. Note that the difference between the second threshold setting method and the first threshold setting method is that in the second threshold setting method, the value of the waveform attenuation rate may vary depending on the RX placed on the TX and powered.

[0328] The reason is that the electrical characteristics of the RX electromagnetically coupled via the power transmission antenna of the TX affect the value of the waveform attenuation rate. For example, when using the quality factor as the waveform attenuation rate, the quality factor measured by the TX in the absence of a foreign object may vary depending on the RX placed on the TX.

[0329] Therefore, the RX holds the quality factor information when a foreign object is placed on the TX in a state without a foreign object for each TX and reports the quality factor information to the TX. The TX adjusts and determines the threshold for each RX based on the quality factor information received from the RX.

[0330] More specifically, in the negotiation phase, the TX receives the FOD status data packet including the information related to the reference quality factor value and adjusts and determines the threshold in the Q value measurement method.

[0331] The reference quality factor value is the quality factor that can be measured at the terminals of the power transmission antenna of the test TX when the RX is placed on the test TX and there is no foreign object nearby.

[0332] The TX regards this reference quality factor value as equivalent to "the Q value information when the RX is placed on the TX in a state without a foreign object" and uses it to determine the threshold. That is, the TX can adjust and determine the threshold for foreign object evaluation using the waveform attenuation method based on the reference quality factor value.

[0333] The reference quality factor value sent from the RX to the TX in the negotiation phase is the information used for foreign object detection in the Q value measurement method that initially measures the quality factor in the frequency domain.

[0334] Here, when using the value of the quality factor as the waveform attenuation rate, although the method for deriving the quality factor is different, even when using the waveform attenuation method for measuring the quality factor in the time domain, for example, the quality factor can be obtained from the waveform in Figure 9 by the above formula 1.

[0335] For this reason, the threshold value of the Q value for the waveform attenuation method can be set based on the reference quality factor value. The value of the waveform attenuation rate obtained by considering a predetermined value (a value corresponding to the measurement error) for the reference quality factor value can be set as the threshold value used for foreign object evaluation.

[0336] In this way, the TX sets the threshold value of the quality factor for the waveform attenuation method based on the information that has been sent from the RX to the TX during the negotiation phase, so that no new measurement or other processing is required to set the threshold value. As a result, the threshold value can be set in a shorter time. The foreign object evaluation based on the set threshold value and the measured value of the quality factor is as described above.

[0337] The third threshold setting method is as follows: The TX measures the waveform attenuation rate in a state where there is no foreign object, and adjusts and determines the threshold value based on the information of the measurement result. The timing of pre-measuring the waveform attenuation rate in a state where there is no foreign object will be described below.

[0338] In the negotiation phase of the WPC standard, if foreign object detection is performed using the Q value measurement method and it is evaluated as there being no foreign object as a result, this phase enters the calibration phase and the power transmission phase. That is, the fact that this phase has entered a phase later than the negotiation phase means that, as a result of foreign object detection using the Q value measurement method, it is evaluated that there is no foreign object.

[0339] There is a high possibility that the waveform attenuation rate in a state where there is no foreign object can be measured in any of the negotiation phase, the calibration phase, and the power transmission phase. Therefore, the timing of measuring the waveform attenuation rate in a state where there is no foreign object can be any of the negotiation phase, the calibration phase, and the power transmission phase.

[0340] For example, assume that the waveform attenuation rate is measured in the power transmission phase. The timing of measuring the waveform attenuation rate in a state where there is no foreign object is set to the first stage of the power transmission phase.

[0341] The reason is that the longer the time elapsed since the Q value measurement method evaluated that there is no foreign object, the higher the probability that there will be a foreign object near the TX and the RX. The timing is specified by the RX or the TX, and the TX measures the waveform attenuation rate at this time and sets the value of the waveform attenuation rate as the threshold value.

[0342] In the case where the RX (or TX) specifies the timing, the RX (or TX) reports the timing by sending a predetermined packet to the TX (or RX). The value obtained by considering a predetermined value (a value corresponding to the measurement error) in the waveform attenuation rate can be set as the threshold value used for foreign object evaluation.

[0343] The fourth threshold setting method is a method in which TX adjusts and determines the threshold according to the power transmission power. The value of the waveform attenuation rate may vary according to the power transmission power of TX. This is because: changes in the calorific value and the characteristics of the electrical circuit of TX, etc., change according to the amount of power transmission power of TX, which affects the value of the waveform attenuation rate.

[0344] TX measures the waveform attenuation rate for each power transmission power and adjusts and determines the threshold based on the measurement results, thereby enabling more accurate foreign object evaluation.

[0345] Figure 11 It is a diagram for explaining the threshold setting method for foreign object evaluation for each power transmission power of TX in the waveform attenuation method. In Figure 11 it, the horizontal axis represents the power transmission power of the power transmission device 100, and the vertical axis represents the waveform attenuation rate (waveform attenuation index) of the voltage waveform or current waveform.

[0346] On the graph line indicated by the straight line segment 1102, the point 1100 corresponds to the power transmission power value Pt1 and the waveform attenuation rate δ1, and the point 1101 corresponds to the power transmission power value Pt2 and the waveform attenuation rate δ2. On this graph line, the point 1103 corresponds to the power transmission power value Pt3 and the waveform attenuation rate δ3.

[0347] First, when power is transmitted from TX, RX controls the load so that RX is in a light load state. The light load state is a state in which no power is supplied to the load of RX, or only power smaller than the threshold is supplied, or power within a predetermined range (hereinafter referred to as the "third range") is supplied.

[0348] The power transmission power value of TX in this state is set to Pt1. In addition, RX sends a packet to TX indicating a request to perform measurement of the waveform attenuation rate. Further, if TX receives the packet, TX stops power transmission or reduces the power transmission power when the load of RX is controlled to the light load state, and measures the waveform attenuation rate δ1.

[0349] At this time, TX identifies the power transmission power value Pt1 and stores CP 1100, which is a calibration point associated with the power transmission power value Pt1 and the waveform attenuation rate δ1, in the memory.

[0350] Subsequently, RX performs control of the load connection state. The load connection state is a state in which, when power is transmitted from TX, the maximum power is supplied to the load of RX, power equal to or greater than the threshold is supplied, or power within a predetermined range (hereinafter referred to as the "fourth range") is supplied.

[0351] Here, the "fourth range" is a range of electric power that is larger than the "third range". The power transmission value of the TX in this state is set to Pt2. In addition, the RX sends a packet to the TX to indicate a request to perform measurement of the waveform attenuation rate.

[0352] In addition, if the TX receives the packet, the TX stops power transmission or reduces the power transmission when the load of the RX is controlled to the load connection state, and measures the waveform attenuation rate δ2.

[0353] At this time, the TX stores the CP 1101 associating the power transmission value Pt2 with the waveform attenuation rate δ2 in the memory. Subsequently, the TX generates a line segment 1102 by performing linear interpolation between CP 1100 and CP 1101.

[0354] The line segment 1102 shows the relationship between the power transmission and the waveform attenuation rate of the waveform observed using the power transmission antenna 105 in the first detection state where no foreign object exists near the TX and the RX. Therefore, based on the line segment 1102, the TX can estimate the waveform attenuation rate of the waveform observed using the power transmission antenna 105 for each power transmission value in the first detection state.

[0355] For example, in the case of the power transmission value Pt3, the waveform attenuation rate is estimated as δ3 according to the point 1103 corresponding to Pt3 on the line segment 1102. Based on the estimation result, the TX can calculate a threshold for evaluating the presence or absence of a foreign object for each power transmission value.

[0356] For example, a waveform attenuation rate that is larger than a predetermined value (a value corresponding to the measurement error) compared to the estimation result of the waveform attenuation rate in the first detection state at a certain power transmission value can be set as the threshold for foreign object evaluation.

[0357] In order for the power transmission device 100 to obtain a combination of the power transmission value and the waveform attenuation rate, the CAL process performed by the power transmission device 100 and the power reception device 200 is hereinafter referred to as the "CAL process of the waveform attenuation method".

[0358] In addition, the power transmission device 100 and the power reception device 200 can perform the CAL process of the waveform attenuation method multiple times. Hereinafter, the CAL process of the waveform attenuation method performed again after the CAL process of the waveform attenuation method has been performed once will be referred to as the "recalibration process of the waveform attenuation method".

[0359] In addition, the recalibration process is abbreviated as the "RECAL process". In the above example, measurements are performed at two points, which are the power transmission values Pt1 and Pt2. Here, in order to further improve the accuracy, measurements can be performed at multiple (three or more) points to calculate the waveform attenuation rate for each power transmission.

[0360] After the RX reports to the TX using a predetermined packet that the RX will perform control of the light load state and control of the load connection state, the RX can perform these controls. Additionally, these two controls can be performed in any order.

[0361] The process for calculating the threshold used in the foreign object evaluation for each load (or each power transmission value) described in this embodiment can be performed in the calibration phase. As described above, in the calibration phase, the TX acquires the data required for performing foreign object detection using the power loss method.

[0362] At this time, the TX acquires data related to the received power value and power loss of each RX when the load state of the RX is the light load state and when the load state of the RX is the load connection state. Thus, in the calibration phase, when the RX is in the light load state and when the RX is in the load connection state, Figure 11 the measurements of CP 1100 and CP 1101 in

[0363] can be performed together with the measurement of power loss. For example, when the TX receives a signal with the first reference received power information from the RX, in addition to performing the predetermined processing to be performed in the calibration phase, the TX also performs the measurement of CP 1100. Although this first reference received power information is the RP1 information defined in the WPC standard, other messages can be used.

[0364] In addition, when the TX receives a signal with the second reference received power information from the RX, in addition to performing the predetermined processing to be performed in the calibration phase, the TX also performs the measurement of CP 1101. Although this second reference received power information is the RP2 information defined in the WPC standard, other messages can also be used.

[0365] Since there is no need to set aside a separate time period for measuring CP 1100 and CP 1101, the measurements of CP 1100 and CP 1101 can be performed in a shorter time.

[0366] In this way, based on the information of the waveform attenuation rate measured by the TX at each power transmission, the TX adjusts and sets the threshold of the waveform attenuation rate for each power transmission. For example, when using the quality factor as the waveform attenuation rate, the TX compares the measured value of the quality factor with the threshold determined by the above method.

[0367] When the measured value of the Q value is less than the threshold, it is evaluated as "foreign object present" or "there is a possibility of foreign object presence". When the measured value of the quality factor is equal to or greater than the threshold, it is evaluated that there is no foreign object or the possibility of foreign object presence is low. As described above, thresholds are set for each power transmission of the TX, enabling more accurate foreign object evaluation.

[0368] There may be more than one threshold value used for foreign object evaluation set by the above method. Multiple threshold values can be set step by step. For example, the first threshold value is set as the evaluation threshold for "abnormal state exists", the second threshold value is set as the evaluation threshold for "high possibility of abnormal state", the third threshold value is set as the evaluation threshold for "low possibility of abnormal state", and the fourth threshold value is set as the evaluation threshold for "abnormal state does not exist".

[0369] In addition, in some cases, it is unlikely that a single run of the foreign object detection process is accurate. For example, when performing foreign object detection using the waveform attenuation method, if power transmission control is performed once and foreign object evaluation is performed based on the waveform attenuation rate at this time, in some cases, there is a possibility that disturbances will occur in the amplitude and phase of the power transmission waveform during the power transmission control time period.

[0370] Noise that may be mixed in during the power transmission control time period, or position offset of the RX placed on the TX, etc. may occur. In this case, when the value of the waveform attenuation rate obtained from the power transmission waveform during a single power transmission control time period is inaccurate, in some cases, there is a possibility that mis-evaluation will occur in the foreign object evaluation.

[0371] Therefore, the TX performs power transmission control multiple times, measures the waveform attenuation rate based on the power transmission waveforms during multiple power transmission control time periods, and is able to perform more accurate foreign object evaluation based on the results of multiple measurements.

[0372] As a method for measuring the coupling state index of the power transmission antenna and the power reception antenna, the first measurement method will be described below. The measurement performed in the first measurement method is hereinafter referred to as "the first measurement". In wireless power transmission, power is transmitted by electromagnetic coupling between the power transmission antenna 105 and the power reception antenna 205.

[0373] By passing an alternating current (AC) through the power transmission antenna 105 and changing the magnetic flux passing through the power reception antenna 205, a voltage is induced in the power reception antenna 205. For example, when all (100%) of the magnetic flux generated by the power transmission antenna passes through the power reception antenna, the coupling coefficient (denoted by k and its value is called the k value), which is an index representing the coupling state of the power transmission antenna and the power reception antenna, satisfies "k = 1".

[0374] In addition, when 70% of the magnetic flux generated by the power transmission antenna passes through the power reception antenna, "k = 0.7" is satisfied. In this case, the remaining magnetic flux (30%) generated by the power transmission antenna is called the leakage magnetic flux (leakage flux).

[0375] This is the magnetic flux generated by the power transmission antenna that does not pass through the power reception antenna. Therefore, when the coupling state between the power transmission antenna and the power reception antenna is good and the k value is large, the transmission efficiency of the power transmitted from TX to RX is high. On the other hand, when the coupling state is not satisfied and the k value is small, the transmission efficiency of the power transmitted from TX to RX is low.

[0376] Factors that reduce the k value include foreign objects (such as metal sheets) entering between the power transmission antenna and the power reception antenna, as well as the positional offset between the power transmission antenna and the power reception antenna. Another reason is that the distance between the power transmission antenna and the power reception antenna becomes larger.

[0377] When a foreign object enters between the power transmission antenna and the power reception antenna, heat may be generated in the foreign object. In addition, if there is a positional offset or separation between the power transmission antenna and the power reception antenna, due to an increase in the leakage magnetic flux (leakage flux), a large amount of noise may be generated in the surrounding area.

[0378] When the k value is small, appropriate control is required to achieve safer and higher-quality wireless power transmission. In this embodiment, in order to improve the detection accuracy of foreign objects and the detection accuracy when there is a positional offset or a large distance, a detection process for the coupling state index (including the coupling coefficient) between the power transmission antenna and the power reception antenna is performed.

[0379] Reference will be made Figure 12 to describe the measurement method of the coupling state index for the power transmission antenna and the power reception antenna. Figure 12 Figure (A) is an equivalent circuit diagram for explaining the first measurement method. The definitions of the quantities related to the power transmission antenna (power transmission coil) on the primary side (TX) will be shown below.

[0380] · r1: The winding resistance of the power transmission antenna.

[0381] · L1: The self-inductance of the power transmission antenna.

[0382] · V1: The power transmission voltage (input voltage) applied to the power transmission antenna measured by TX.

[0383] In addition, the definitions of the quantities related to the power reception antenna (power reception coil) on the secondary side (RX) will be shown below.

[0384] · r2: The winding resistance of the power reception antenna.

[0385] · L2: The self-inductance of the power reception antenna.

[0386] · V2: The power reception voltage (output voltage) applied to the power reception antenna measured by RX.

[0387] The coupling coefficient (k) between the power transmission antenna and the power reception antenna can be calculated by Equation 2 below.

[0388]

[0389] When the TX calculates the coupling coefficient k, the RX reports to the TX the measured received voltage V2 and the value of the self-inductance L2 of the receiving antenna that the RX has previously held. The TX uses the measured transmitted voltage V1, the value of the self-inductance L1 of the transmitting antenna that was previously held, and the received voltage V2 and the value of the self-inductance L2 received from the RX to calculate the value of k.

[0390] Alternatively, the RX can report V2 and a constant calculated using either or both of L1 and L2 to the TX, and the TX can use the constant received from the RX, V2, and the measured transmitted voltage V1 of the TX to calculate the value of k.

[0391] On the other hand, when the RX calculates the coupling coefficient k, the TX reports to the RX the measured transmitted voltage V1 and the value of the self-inductance L1 of the transmitting antenna that the TX has previously held. The RX uses the measured received voltage V2, the value of the self-inductance L2 of the receiving antenna that was previously held, and the transmitted voltage V1 and the value of the self-inductance L1 received from the TX to calculate the value of k.

[0392] Alternatively, the TX can report V1 and a constant calculated using either or both of L1 and L2 to the RX, and the RX can use the constant received from the TX, V1, and the measured received voltage V2 of the RX to calculate the value of k.

[0393] The transmitted voltage V1 is calculated by the TX by actually measuring the voltage applied to the transmitting antenna, or is calculated by the TX based on the set value of the transmitted power. Alternatively, the transmitted voltage V1 can be set to the set value of the transmitted voltage during transmission.

[0394] In addition, the transmitted voltage V1 applied to the transmitting antenna can be obtained based on the transmitted voltage (represented by V3) applied to the circuit (e.g., an inverter) of the transmitting unit 103 of the TX and the voltage applied across the resonant capacitor 107.

[0395] Here, the transmitted voltage V3 is, for example, the inverter input voltage input to the inverter of the transmitting unit 103 of the TX, or the inverter output voltage output by the inverter. In this case, the transmitted voltage V3 can also be calculated by the TX based on the set value of the transmitted power.

[0396] Alternatively, the TX can actually measure the transmitted voltage V3 and the voltage applied across the resonant capacitor 107 and use them to obtain the transmitted voltage V1. Alternatively, the TX can send the measured transmitted voltage V3 and the voltage applied across the resonant capacitor 107 to the RX, and the RX can calculate the value of k by obtaining the transmitted voltage V1.

[0397] In addition, when the first measurement is performed at the TX or RX, the RX can control the third switch unit 213 to be turned off, so that the terminals of the power receiving antenna 205 are in an open state. Thus, as shown in (A) of Figure 12 , both ends of the power receiving antenna can be kept open.

[0398] Since there is no influence caused by the resonance capacitor 211, the power receiving unit 203, the charging unit 206, or the battery 207 in the first measurement, the coupling coefficient k can be measured with higher accuracy. In addition, the power receiving voltage V2 applied to the power receiving antenna can be obtained based on the power receiving voltage (represented by V4) applied to the circuit owned by the power receiving unit 203 of the RX and the voltage applied to both ends of the resonance capacitor 211.

[0399] Here, the power receiving voltage V4 is, for example, the rectifier unit input voltage input to the rectifier unit owned by the power receiving unit 203 of the RX. Alternatively, the power receiving voltage V2 applied to the power receiving antenna can be obtained based on the power receiving voltage (represented by V5) applied to the circuit owned by the power receiving unit 203 of the RX and the voltage applied to both ends of the resonance capacitor 211.

[0400] Here, the power receiving voltage V5 is, for example, the rectifier unit output voltage output from the rectifier unit owned by 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 to both ends of the resonance capacitor 211, and use them to obtain the power receiving voltage V2.

[0401] Alternatively, the RX can actually measure the power receiving voltage V5 and the voltage applied to both ends of the resonance capacitor 211, and use them to obtain the power receiving voltage V2. Alternatively, the RX can send the measured values of the power receiving voltage V4 and the voltage applied to both ends of the resonance capacitor 211 to the TX, and the TX can calculate the k value by obtaining the power receiving voltage V2.

[0402] Alternatively, the RX can send the measured values of the power receiving voltage V5 and the voltage applied to both ends of the resonance capacitor 211 to the TX, and the TX can calculate the k value by obtaining the power receiving voltage V2.

[0403] Alternatively, when the first measurement is performed at the TX or RX, the RX can be controlled to be in a light load state or a load connection state. By keeping the load state of the RX constant, the coupling coefficient k can be measured with higher accuracy.

[0404] Alternatively, TX or RX can be controlled to perform a first measurement in two states: when RX is in a light load state and when RX is in a load connection state. Alternatively, TX or RX can be controlled such that RX performs the first measurement in each of three or more load states. The coupling state in the load states of multiple RXs is measured, and based on the measured coupling state, the coupling state can be evaluated with higher accuracy.

[0405] In addition to the coupling coefficient, there are multiple quantities that can be used as indicators representing the electromagnetic coupling state of the power transmission antenna and the power reception antenna. In the present disclosure, these are collectively referred to as "coupling state indicators". Each coupling state indicator has a value corresponding to the electromagnetic coupling state of the power transmission antenna and the power reception antenna.

[0406] Even when using coupling state indicators other than the coupling coefficient, the details of this embodiment can be similarly applied.

[0407] For example, there is a method of using the power transmission voltage V3 applied to the circuit (e.g., inverter) owned by the power transmission unit 103 of TX and the power reception voltage V4 applied to the circuit (e.g., rectifier unit) owned by the power reception unit 203 of RX as coupling state indicators.

[0408] Using these voltage values, the coupling state indicator of the power transmission antenna and the power reception antenna can be calculated. Alternatively, the coupling state indicator of the power transmission antenna and the power reception antenna can be calculated using the power transmission voltage V3 applied to the circuit (e.g., inverter) owned by the power transmission unit 103 of TX and the voltage V5 applied to the circuit (e.g., rectifier unit) owned by the power reception unit 203 of RX.

[0409] Here, the voltage V5 is, for example, the rectifier unit output voltage output from the rectifier unit owned by the power reception unit 203 of RX, or the voltage applied to the load (charging unit, battery). TX reports the power transmission voltage V3 to RX, and RX can use V4 or V5 and the reported V3 to calculate the coupling state indicator.

[0410] At this time, TX reports the constant calculated using the electrical characteristics (e.g., L1) of the power transmission antenna to RX, and RX can use this constant to calculate the coupling state indicator.

[0411] Alternatively, RX reports the power reception voltage V4 or V5 to TX, and TX uses V3 and the reported voltage V4 or V5 to calculate the value of the coupling state indicator. At this time, RX reports the constant calculated using the electrical characteristics (e.g., L2) of the power reception antenna to TX, and TX can use this constant to calculate the coupling state indicator.

[0412] TX and RX transmit and receive information such as values of voltages V1 to V5, values of self-inductances L1 and L2, or constants representing electrical characteristics of the power transmitting antenna or the power receiving antenna. The timing of measuring the voltage value and the timing of transmitting and receiving each piece of information will be described below.

[0413] The measurement of each voltage value is performed, for example, in the Ping phase. In the Ping phase, TX transmits DP to RX. Thus, any one of the voltage values of V1, V2, V3, V4, and V5 generated when transmitting DP can be used.

[0414] In the Ping phase, TX and RX measure any one of the values of V1 to V5, and store and hold the measured value in memory 106 or memory 208.

[0415] TX sends a predetermined transmission request packet to RX to request RX to send a packet including information related to any one or all of (one or more than one) voltage values of V2, V4, and V5. When RX receives this transmission request packet, RX sends a predetermined packet including information related to any one or all of (one or more than one) voltage values of V2, V4, and V5 to TX.

[0416] TX receives a predetermined packet including information related to any one or all of (one or more than one) voltage values of V2, V4, and V5 reported from RX, and stores this information in memory 106. The information included in the predetermined packet can include not only the received voltage of RX, but also information such as received power, requested received power value, value of self-inductance L2, and constants calculated using the electrical characteristics of the power receiving antenna.

[0417] In addition, information related to the temperature of RX can be included. TX receives a signal including this information from RX, and can use this information and the coupling state indicator for more appropriate control. As the predetermined packet, a signal strength data packet can be used to report information of RX to TX.

[0418] Alternatively, the predetermined packet can be an identification data packet or an extended identification data packet in the I&C phase.

[0419] Alternatively, the predetermined packet can be a configuration data packet. Alternatively, the predetermined packet can be a packet in the calibration phase or the power transmission phase.

[0420] That is to say, the predetermined packet can be RP1, RP2, or RP0. The present invention is not limited to the example where TX uses the voltage value generated when transmitting DP. TX can use any one of the voltage values of V1 to V5 generated when transmitting AP in the selection phase.

[0421] Alternatively, any one of voltage values V1 to V5 generated when the TX supplies power to the RX during the power transmission phase may be used.

[0422] The RX sends a predetermined transmission request packet to the TX to request the TX to send a packet including information related to (one or more than one) voltage values of either or both of V1 and V3. When the TX receives the transmission request packet, the TX sends a predetermined packet including information related to either or both of voltage values V1 and V3 to the RX.

[0423] The RX receives a predetermined packet including information related to either or both of voltage values V1 and V3 reported from the TX, and stores the information in the memory 208. The information included in the predetermined packet may include not only the voltage of the TX, but also information such as the power transmission value, the available power transmission value, the value of the self-inductance L1, and a constant calculated using the electrical characteristics of the power transmission antenna.

[0424] In addition, alternatively, the information may include the foreign object detection result using a foreign object detection method (power loss method, Q value measurement method, waveform attenuation method), information related to the temperature of the TX, and information related to the current value of the power transmission antenna 105.

[0425] The RX receives the information from the TX, and may perform more appropriate control using the information and the coupling state index. In addition, the RX may use the power supply capacity (CAP) data packet as the predetermined packet to report the information of the TX to the RX.

[0426] Alternatively, the TX may use the power supply identification (ID) data packet to report information to the RX.

[0427] The present invention is not limited to the example in which the TX uses the voltage value generated when sending the DP. The TX may use any one of voltage values V1 to V5 generated when sending the AP during the selection phase. Alternatively, any one of voltage values V1 to V5 generated when the TX sends power to the RX during the power transmission phase may be used.

[0428] When performing the first measurement, the RX may control the third switch unit 213 between the resonant capacitor 211 and the power receiving unit 203 to be turned off, so that the terminals of the circuit formed by the power receiving antenna 205 and the resonant capacitor 211 are in an open state.

[0429] Therefore, since there is no influence caused by the power receiving unit 203, the charging unit 206, and the battery 207 when performing the first measurement, the coupling state index can be measured with higher accuracy. Alternatively, when the RX performs the first measurement method, the RX may control the load to be in the above-described light load state.

[0430] When the first measurement method is performed at the RX, the load can be controlled so that the load is in the load connection state. Therefore, the coupling state index can be measured while keeping the load state in a predetermined state, enabling more accurate state detection.

[0431] As another example of the method for measuring the coupling state index of the power transmission antenna and the power reception antenna, the second measurement method will be described below. The measurement performed in the second measurement method is hereinafter referred to as "the second measurement". Figure 12 (B) is an equivalent circuit diagram for explaining the second measurement method.

[0432] r1, r2, L1, and L2 are the same as those in Figure 12 (A). The definitions of the quantities related to the power transmission antenna (coil) on the primary side (TX) will be shown below.

[0433] · V6: The input voltage (transmission voltage) of the power transmission antenna when the power reception antenna side is in the short-circuit state.

[0434] · V7: The input voltage (transmission voltage) of the power transmission antenna when the power reception antenna side is in the open state.

[0435] · I1: The current flowing through the power transmission antenna when the power reception antenna side is in the short-circuit state.

[0436] · I2: The current flowing through the power transmission antenna when the power reception antenna side is in the open state.

[0437] The coupling coefficient k can be calculated using the following Equation 3.

[0438]

[0439] In Equation 3, Lsc represents the inductance of the power transmission antenna when the two ends of the power reception antenna are short-circuited. For example, the control unit 201 sets the third switch unit 213 and the second switch unit 210 to the ON state (short-circuit state).

[0440] 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 based on the input voltage V6 and the current I1 of the power transmission antenna.

[0441] In Equation 3, Lopen represents the inductance of the power transmission antenna when the two ends of the power reception antenna are open. For example, the control unit 201 sets the third switch unit 213 to the OFF state (open state). In this state, the Lopen value can be obtained by measuring the inductance value of the power transmission antenna.

[0442] The inductance value of the power transmission antenna can be obtained based on the input voltage V7 and current I2 of the power transmission antenna. In the second measurement method, the coupling state index (coupling coefficient) can be obtained based on the input voltage and current of the power transmission antenna when the two ends of the power reception antenna are short-circuited and open.

[0443] In addition, the 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 voltages V6 and V7 represent the power transmission voltages applied to the circuit (e.g., inverter) included in the power transmission unit 103.

[0444] Here, the power transmission voltages V6 and V7 applied to the circuit included in the power transmission unit 103 of the TX are, for example, the inverter input voltage or the inverter output voltage. In addition, the input voltages V6 and V7 can be the voltages applied to the two terminals of the series resonance circuit composed of the power transmission antenna and the resonance capacitor.

[0445] Alternatively, the power transmission voltage applied to the circuit (e.g., inverter) included in the power transmission unit 103 and the voltage applied to both ends of the resonance capacitor 107 can be measured, and the voltage applied to the power transmission antenna can be calculated based on these results.

[0446] That is, the coupling state index can be obtained based on the measurement results of the power transmission voltage applied to the circuit (e.g., inverter) included in the power transmission unit 103 and the voltage applied to 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 based on the set value of the power transmission power.

[0447] In addition, in Figure 12 (B), the current I1 or I2 is not limited to the current flowing through the power transmission antenna, but can be the current flowing through the circuit (e.g., inverter) included in the power transmission unit 103. Here, the current flowing through the circuit included in the power transmission unit 103 of the TX is, for example, the inverter input current or the inverter output current.

[0448] Regarding the open state and short-circuit state of the power reception antenna, an example of the control unit 201 implemented by controlling the second switch unit 210 and the third switch unit 213 has been described. These states can be implemented using the power reception unit 203.

[0449] In addition, instead of the short-circuit state, a light load state (light load state) can be used. In addition, instead of the open state, a connected load state (load connection state) can be used.

[0450] In the second measurement method, the TX can calculate the coupling state index by measuring the input voltages V6 and V7 and the currents I1 and I2. Thus, since information such as the voltage value measured by the RX or the inductance value of the power receiving antenna is not required, the RX does not need to report such information to the TX.

[0451] Here, when the TX measures the input voltage V6 and the current I1, the RX needs to short-circuit (make short) the two terminals of the circuit including the power receiving antenna. In addition, when the TX measures the input voltage V7 and the current I2, the RX needs to open (make open) the two terminals of the circuit including the power receiving antenna.

[0452] That is, according to the timing of the TX measuring the input voltage and current, the RX needs to control the two terminals of the circuit including the power receiving antenna to the SHORT (short-circuited) state or the OPEN (open) state.

[0453] If the control is completed, the TX performs the measurement. The timing of the measurement is determined by the TX and reported to the RX, or determined by the RX and reported to the TX. Additionally, if the control of making the two terminals of the circuit including the power receiving antenna to the SHORT (short-circuited) state or the OPEN (open) state is completed, the RX provides a report to the TX.

[0454] These reports are provided through communication based on the WPC standard executed between the first communication unit 104 of the TX and the first communication unit 204 of the RX, or through communication using a standard other than the WPC standard executed between the second communication unit 109 of the TX and the second communication unit 212 of the RX.

[0455] The measurement of the input voltages V6 and V7 and the currents I1 and I2 is performed, for example, in the Ping phase. In the Ping phase, the TX sends a DP to the RX. Thus, the values of V6 and V7 and the currents I1 and I2 generated when sending the DP can be used.

[0456] In the Ping phase, the TX acquires the values of V6, V7, I1, and I2, stores them in the memory 106, and calculates the coupling state index. The present invention is not limited to the example where the TX uses the voltage values and current values generated when sending the DP.

[0457] For example, the values of V6, V7, I1, and I2 generated when the TX sends an AP in the Selection phase can be used. Alternatively, the voltage values of V6, V7, I1, and I2 generated when the TX transmits power to the RX in the Power Transfer phase can be used.

[0458] In the present disclosure, both the first measurement method and the second measurement method are applicable to the measurement method of the coupling state index used for the power transmission antenna and the power reception antenna. The following will describe a method for setting a state evaluation threshold for the coupling state index obtained by the first measurement method or the second measurement method.

[0459] State evaluation includes evaluations related to the detection of foreign objects between the power transmission antenna and the power reception antenna, evaluations related to the detection of position offsets of the power transmission antenna and the power reception antenna, and evaluations related to the detection of separation of the power transmission antenna and the power reception antenna from each other, etc.

[0460] The first measurement or the second measurement can be performed and the state evaluation threshold is used to evaluate the presence or absence of a state anomaly. The following will describe the first threshold setting method to the fourth threshold setting method.

[0461] The first threshold setting method is a method for setting the value of the coupling state index in a state where there is no state anomaly as the threshold for the coupling state index used for state detection between the power transmission antenna and the power reception antenna. In state detection, for example, evaluation results such as "state anomaly exists", "high possibility of state anomaly", "low possibility of state anomaly", and "state anomaly does not exist" can be obtained.

[0462] Assume that the RX is placed on the test TX and there is no state anomaly between the power transmission antenna and the power reception antenna. In this case, the value of the coupling state index of the test TX including the power transmission antenna and the RX including the power reception antenna can be set as the threshold.

[0463] The RX holds the pre-measured value of the coupling state index (threshold) in the memory and reports the threshold to the TX. The TX uses this threshold to perform an evaluation process related to state detection. Regarding this threshold, the RX can send the threshold included in the FOD status data packet defined by the WPC standard to the TX.

[0464] Alternatively, the value of the coupling state index of the power transmission antenna and the power reception antenna that achieves a predetermined power transmission efficiency can be set as the threshold. In state detection, for example, the following evaluation results are obtained.

[0465] · "The predetermined power transmission efficiency will not be achieved" or "the coupling between the power transmission antenna and the power reception antenna is weak".

[0466] · "There is a high possibility that the predetermined power transmission efficiency will not be achieved" or "there is a possibility that the coupling between the power transmission antenna and the power reception antenna is weak".

[0467] · "There is a high possibility that the predetermined power transmission efficiency will be achieved" or "there is a possibility that the coupling between the power transmission antenna and the power reception antenna is good".

[0468] · "Achieved a predetermined power transmission efficiency" or "The coupling state between the power transmission antenna and the power reception antenna is good."

[0469] Here, it is assumed that: The RX is placed on the test TX, there is no abnormal state between the power transmission antenna and the power reception antenna, and a predetermined power transmission efficiency is obtained. In this case, the value of the coupling state index of the test TX including the power transmission antenna and the RX including the power reception antenna can be set as a threshold.

[0470] The RX holds the value of the pre-measured coupling state index as a threshold in the memory and reports the threshold to the TX. The TX uses this threshold to perform the evaluation process related to state detection. Regarding this threshold, the RX can send the threshold included in the FOD status data packet defined in the WPC standard to the TX.

[0471] The second threshold setting method is as follows: In a predetermined state, the TX and the RX set the coupling state index measured by the first measurement method or the second measurement method as a threshold. The predetermined state is a state where there is no abnormal state between the power transmission antenna and the power reception antenna.

[0472] In the method for checking this state, the state detection of the TX and the RX can be utilized, such as foreign object detection using the power loss method, foreign object detection using the waveform attenuation method, foreign object detection using the Q value measurement method, and foreign object detection based on the temperature of the TX or the RX to be described later.

[0473] As a result, when it is determined that there is no abnormal state, it can be confirmed with a high probability that "there is no abnormal state between the power transmission antenna and the power reception antenna." That is, this confirmation is performed by methods and means other than the first measurement method or the second measurement method.

[0474] As a result, when the result is evaluated as "no abnormal state" (or "no foreign object"), the first measurement method or the second measurement method is used to measure the coupling state index, and an appropriate threshold is set based on the measurement result.

[0475] For example, in the WPC standard, the foreign object detection process using the Q value measurement method is performed in the negotiation phase or the re-negotiation phase. As a result of the foreign object detection process, when it is evaluated as "no abnormal state" (or "no foreign object"), after the negotiation phase or the re-negotiation phase, the first measurement method or the second measurement method is used to measure the coupling state index.

[0476] A more appropriate threshold can be set based on the measurement result. In addition, the foreign object detection process using the power loss method is performed in the power transmission phase. After performing the foreign object detection process, the first measurement method or the second measurement method is used to measure the coupling state index, and a more appropriate threshold can be set based on the measurement result.

[0477] Alternatively, the TX may perform foreign object detection processing using the AP or DP transmitted by the TX during the selection phase or the Ping phase, or the quality factor measured by the waveform attenuation method, etc.

[0478] In this case, after the stage of performing the foreign object detection processing, 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.

[0479] Alternatively, foreign object detection processing using the above-described waveform attenuation method is performed during the power transmission phase. After performing the foreign object detection processing, the coupling state index is measured using the first measurement method or the second measurement method, and a more appropriate threshold value may be set based on the measurement result.

[0480] The following will refer to Figure 13 to describe the third threshold setting method. Figure 13 is a diagram for explaining the threshold setting method in state detection using the coupling state index. In Figure 13 the horizontal axis represents the power transmitted, and the vertical axis represents the coupling state index.

[0481] On the graph line indicated by the straight line segment 1202, the point 1200 corresponds to the power transmission value Pt1 and the coupling state index value k1 of the power transmitted, and the point 1201 corresponds to the power transmission value Pt2 and the coupling state index value k2 of the power transmitted.

[0482] On this graph line, the point 1203 corresponds to the power transmission value Pt3 and the coupling state index value k3 of the power transmitted. When calculating each coupling state index value, the above-described first measurement method or second measurement method may be used.

[0483] As Figure 3 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 according to the state of each load. In order to evaluate the presence or absence of a state abnormality according to the state of the load, a threshold value needs to be set for the coupling state index.

[0484] First, when power is transmitted from the TX, the RX controls the load so that the load is in a light load state. The light load state is a state in which no power is supplied to the load of the RX or power equal to or less than the threshold value is supplied.

[0485] Alternatively, the light load state is a load state in which the power reception value of the RX falls within a predetermined range (hereinafter referred to as the "fifth range") that has been previously determined. The power transmission value of the TX in this state is set to Pt1. In addition, the RX transmits a packet for instructing a request to perform measurement of the coupling state index to the TX.

[0486] Alternatively, the TX may send a packet to the RX to indicate the execution of the measurement of the coupling state index. In this state, the TX and the RX measure the power transmission voltage on the TX side and the power reception voltage on the RX side.

[0487] The TX and the RX exchange information such as the values of V1 to V7, the values of the self-inductances L1 and L2, or constants calculated using the electrical characteristics of the power transmission antenna and the power reception antenna, and the TX or the RX calculates the coupling state index value k1.

[0488] When the RX calculates the coupling state index value k1, the RX reports the result to the TX. When the TX calculates the coupling state index value k1, the TX reports the result and Pt1 to the RX. At this time, the TX identifies the power transmission power value Pt1 and stores the CP 1200 associating Pt1 with k1 in the memory.

[0489] In addition, alternatively, the RX stores the CP 1200 associating Pt1 with k1 in the memory. Subsequently, when power is transmitted from the TX, the RX controls the load of the RX such that the RX is in the load connection state. The load connection state is a state in which the maximum power is supplied to the load of the RX and a state in which power equal to or greater than the threshold value is supplied.

[0490] Here, the "maximum power" refers to the power whose value is close to the reference power. Alternatively, the load state is a load state in which the power reception power value of the RX falls within a predetermined range (hereinafter referred to as the "sixth range") that has been previously determined.

[0491] Here, the sixth range is a range of power values higher than the fifth range. The power transmission power value of the TX in this state is set to Pt2. In addition, the RX sends a packet to the TX to indicate a request to execute the measurement of the coupling state index. Alternatively, the TX sends a packet to the RX to indicate a request to execute the measurement of the coupling state index.

[0492] In this state, the TX and the RX measure the power transmission voltage on the TX side and the power reception voltage on the RX side. The TX and the RX exchange information such as the values of V1 to V7, the values of the self-inductances L1 and L2, or constants calculated using the electrical characteristics of the power transmission antenna and the power reception antenna, and the TX or the RX calculates the coupling state index value k2.

[0493] When the RX calculates the coupling state index value k2, the RX reports the result to the TX. When the TX calculates the coupling state index value k2, the TX reports the result and Pt2 to the RX. The TX stores the CP 1201 associating Pt2 with k2 in the memory.

[0494] Alternatively, RX stores CP 1201 that associates Pt2 with k2 in a memory. Subsequently, TX performs linear interpolation between CP1200 and CP 1201 to generate line segment 1202.

[0495] Line segment 1202 shows the relationship between the power transmission power and the coupling state index in a state where there is no state abnormality around TX and RX. Using line segment 1202, TX can estimate the coupling state index value for each power transmission power value in a state where there is no state abnormality around TX and RX.

[0496] For example, assume that the power transmission power value is Pt3. In this case, the coupling state index value k3 can be estimated based on point 1203 corresponding to the power transmission power value Pt3 on line segment 1202. Based on the estimation result, TX can calculate a threshold for evaluating the presence of a state abnormality for each power transmission power value.

[0497] For example, the coupling state index value obtained by considering a predetermined value (a value corresponding to a measurement error) in the estimation result of the coupling state index value in the case of the absence of a state abnormality at a certain power transmission power value can be set as the evaluation threshold.

[0498] In this way, the calibration process performed by power transmission device 100 and power reception device 200 to obtain a combination of a power transmission power value and a coupling state index value by power transmission device 100 is referred to as the "CAL process of the coupling state index measurement method". In addition, power transmission device 100 and power reception device 200 can perform the CAL process of the coupling state index measurement method multiple times.

[0499] The CAL process of the coupling state index measurement method performed again after performing the CAL process of the coupling state index measurement method once is hereinafter referred to as the "recalibration process of the coupling state index measurement method".

[0500] In addition, the recalibration process is abbreviated as the RECAL process. RX can control the load to enter the light load state and the load connection state after reporting the execution control to TX. In addition, either one of these two controls can be performed first.

[0501] In this embodiment, the operation for calculating the evaluation threshold for state detection for each load (or for each power transmission power value) is performed, for example, in the calibration phase. In this phase, TX acquires the data required for performing foreign object detection using the power loss method.

[0502] At this time, TX acquires data related to the power loss amounts when the load state of RX is in the light load state and when the load state of RX is in the load connection state. Therefore, in the calibration phase, when RX is in the light load state and in the load connection state,Figure 13 The measurements of CP 1200 and CP 1201 in can be performed together with the measurement of power loss.

[0503] That is, when the TX receives the first reference received power information from the RX, in addition to the predetermined processing to be performed in the calibration phase, the TX also measures CP 1200. Although the first reference received power information is based on the information of RP1 defined in the WPC standard, other messages can also be used.

[0504] In addition, when the TX receives the second reference received power information from the RX, in addition to the predetermined processing to be performed in the calibration phase, the TX also measures CP 1201. Although the second reference received power information is based on the information of RP2 defined in the WPC standard, other messages can also be used. In this way, since there is no need to set a separate time period for measuring CP 1200 and CP 1201, CP 1200 and CP 1201 can be measured in a shorter time.

[0505] The fourth threshold setting method is a method in which the TX or RX pre-sets a threshold for the coupling state index whose value falls within a predetermined range. Regarding this threshold, a predetermined value that has been determined in advance is held by the TX or RX as a common value of the RX that does not depend on the transmitted power.

[0506] The threshold can be a fixed value that does not depend on the situation, or can be a variable value determined by the TX or RX according to the situation. For example, if the coupling state index is defined as the coupling coefficient k, the range of the k value satisfies "0 ≤ k ≤ 1".

[0507] For example, when "0 ≤ k < 0.2" is satisfied, the TX or RX determines that the state is "presence of abnormal state", and when "0.2 ≤ k < 0.5" is satisfied, the TX or RX determines that the state is "high possibility of abnormal state". When "0.5 ≤ k < 0.8" is satisfied, the TX or RX determines that the state is "low possibility of abnormal state", and when "0.8 ≤ k ≤ 1" is satisfied, the TX or RX determines that the state is "absence of abnormal state".

[0508] Data related to the conditions for the k value is pre-held in the memory, and the determination process is performed based on this data.

[0509] Alternatively, when "0 ≤ k < 0.2" is satisfied, for example, the TX or RX can determine that "predetermined power transmission efficiency is not obtained" or "the coupling between the power transmission antenna and the power reception antenna is weak".

[0510] When "0.2 ≤ k < 0.5" is satisfied, the TX or RX determines that "there is a high possibility of not obtaining the predetermined power transmission efficiency" or "there is a possibility that the coupling between the power transmission antenna and the power reception antenna is weak".

[0511] When TX or RX satisfies "0.5 ≤ k < 0.8", it is determined that "there is a high possibility of achieving the predetermined power transmission efficiency" or "there is a possibility that the coupling state between the power transmission antenna and the power reception antenna is good".

[0512] When TX or RX satisfies "0.8 ≤ k ≤ 1", it is determined that "the predetermined power transmission efficiency has been achieved" or "the coupling state between the power transmission antenna and the power reception antenna is good". Data related to the conditions for the k value is pre-stored in the memory, and the determination process is performed based on this data.

[0513] In addition, even when setting the evaluation threshold for state detection using the coupling state index, a value obtained by considering a predetermined value (a value corresponding to the measurement error) in the coupling state index value calculated based on the measurement result or received information can be set as the evaluation threshold. As described above, the threshold is not limited to one, and multiple thresholds can be set step by step.

[0514] The timing for calculating the coupling state between the power transmission antenna and the power reception antenna using the first measurement method or the second measurement method will be described below. The calculation (measurement) of the coupling state index is performed by RX that sends a predetermined packet to TX.

[0515] Here, the predetermined packet is a signal strength data packet sent by RX to TX. Alternatively, the predetermined packet can be an identification data packet, an extended identification data packet, or a configuration data packet in the I&C phase.

[0516] Alternatively, the predetermined packet can be a packet in the calibration phase or the power transmission phase. That is, the predetermined packet can be RP1, RP2, or RP0.

[0517] When TX receives the predetermined packet from RX, TX calculates the coupling state index between the power transmission antenna and the power reception antenna. In addition, TX performs an evaluation by comparing the evaluation threshold set by the above method with the calculated coupling state index.

[0518] When it is evaluated that "there is no state abnormality", TX sends an affirmative response ACK for RX or state information indicating "there is no state abnormality" to RX. When it is evaluated that "the possibility of state abnormality is low" and when it is evaluated that "the possibility of state abnormality is high", TX sends state information indicating each evaluation result to RX.

[0519] When it is evaluated that "there is a state abnormality", TX sends a negative response NAK for RX or state information indicating "there is a state abnormality" to RX.

[0520] Alternatively, when it is evaluated as "achieved the predetermined power transmission efficiency" or "good coupling state between the power transmission antenna and the power reception antenna", the TX sends an affirmative response ACK to the RX or sends status information indicating the evaluation result to the RX.

[0521] When it is evaluated as "high possibility of achieving the predetermined power transmission efficiency" or "possibility of good coupling state between the power transmission antenna and the power reception antenna", the TX sends status information indicating the evaluation result to the RX.

[0522] When it is evaluated as "high possibility of not achieving the predetermined power transmission efficiency" or "possibility of weak coupling between the power transmission antenna and the power reception antenna", the TX sends status information indicating the evaluation result to the RX.

[0523] When it is evaluated as "did not achieve the predetermined power transmission efficiency" or "weak coupling between the power transmission antenna and the power reception antenna", the TX sends a negative response NAK to the RX or sends status information indicating the evaluation result to the RX.

[0524] The status information is, for example, numerical information corresponding to the status as follows.

[0525] · Status information "0" corresponding to the following evaluation results: "no status anomaly", "achieved the predetermined power transmission efficiency", or "good coupling state between the power transmission antenna and the power reception antenna".

[0526] · Status information "1" corresponding to the following evaluation results: "low possibility of status anomaly", "high possibility of achieving the predetermined power transmission efficiency", or "possibility of good coupling state between the power transmission antenna and the power reception antenna".

[0527] · Status information "2" corresponding to the following evaluation results: "high possibility of status anomaly", "fact of high possibility of not achieving the predetermined power transmission efficiency", or "possibility of weak coupling between the power transmission antenna and the power reception antenna".

[0528] · Status information "3" corresponding to the following evaluation results: "status anomaly exists", "cannot achieve the predetermined power transmission efficiency", or "weak coupling between the power transmission antenna and the power reception antenna".

[0529] Alternatively, the calculation (measurement) of the coupling state index is performed by the TX that sends a predetermined packet to the RX. The predetermined packet is a power supply device capability (CAP) data packet sent by the TX to the RX.

[0530] Alternatively, the predetermined packet is a power supply device identification (ID) data packet. When the RX receives the predetermined packet from the TX, the RX calculates the coupling state index of the power transmission antenna and the power reception antenna.

[0531] In addition, the RX evaluates the state by comparing the evaluation threshold set by the above method with the calculated coupling state index. When the evaluation is "no state abnormality exists", the RX sends a predetermined packet including state information indicating the evaluation result to the TX.

[0532] When the evaluation is "low possibility of state abnormality" and when the evaluation is "high possibility of state abnormality", the RX sends a predetermined packet including state information indicating each evaluation result to the TX. When the evaluation is "state abnormality exists", the RX sends a predetermined packet including state information indicating the evaluation result to the TX.

[0533] Alternatively, when the evaluation is "predetermined power transmission efficiency achieved" or "good coupling state between the power transmission antenna and the power reception antenna", the RX sends state information indicating the evaluation result to the TX.

[0534] When the evaluation is "high possibility of achieving predetermined power transmission efficiency" or "possibility of good coupling state between the power transmission antenna and the power reception antenna", the RX sends state information indicating the evaluation result to the TX.

[0535] When the evaluation is "fact of high possibility of not achieving predetermined power transmission efficiency" or "possibility of weak coupling between the power transmission antenna and the power reception antenna", the RX sends state information indicating the evaluation result to the TX.

[0536] When the evaluation is "unable to achieve predetermined power transmission efficiency" or "weak coupling between the power transmission antenna and the power reception antenna", the RX sends state information indicating the evaluation result to the TX. Examples of the state information are as described above.

[0537] A foreign object detection method based on the temperature of the TX or RX will be described below. It is assumed that the TX and the RX each have temperature sensors at multiple locations. In particular, the power transmission antenna 105, the charging stand 300, and the power reception antenna 205 are arranged with temperature sensors at a higher density than other locations.

[0538] Foreign objects existing between the TX and the RX can be detected with higher accuracy. The TX or the RX performs foreign object detection processing based on the detected temperature. The TX acquires the detection values of the respective temperature sensors at a predetermined timing.

[0539] The predetermined timing occurs for each predetermined time period that has been previously determined, or occurs when the TX receives a predetermined packet from the RX. When the detection value of the temperature sensor is greater than the threshold, the TX evaluates that the possibility of foreign object existence is high.

[0540] In addition, the TX calculates a temperature rise rate based on a plurality of temperature detection values acquired at a predetermined timing. If the temperature rise rate is greater than the threshold, the TX evaluates that the possibility of foreign object existence is high.

[0541] The evaluation result is reported to the RX using a predetermined packet. Alternatively, when the evaluation result is obtained, the TX performs control to limit the above power transmission (stop power transmission or reduce power transmission power).

[0542] The foreign object detection process based on the temperature of the RX will be described below. The RX acquires the detection values of the respective temperature sensors at a predetermined timing. The predetermined timing occurs for each predetermined time period that has been previously determined, or when the RX receives a predetermined packet from the TX.

[0543] When the detection value of the temperature sensor is greater than the threshold value, the RX evaluates that the possibility of the presence of a foreign object is high. In addition, the RX calculates the temperature rise rate based on the plurality of temperature detection values acquired at the predetermined timing.

[0544] When the temperature rise rate is greater than the threshold value, the RX evaluates that the possibility of the presence of a foreign object is high. The RX reports the evaluation result to the TX using a predetermined packet. Alternatively, when the evaluation result is obtained, the RX performs a process of sending a predetermined packet to the TX to request restriction of power transmission (stop power transmission or reduce power transmission power).

[0545] The foreign object detection method based on the current value related to the current flowing through the power transmission antenna of the TX (hereinafter referred to as the "first current value") and the current value related to the current flowing through the power reception antenna of the RX (hereinafter referred to as the "second current value") will be described below.

[0546] The TX or RX performs a foreign object detection process based on the detected first current value or second current value. The TX acquires the first current value at a predetermined timing. The predetermined timing occurs for each predetermined time period that has been previously determined, or when the TX receives a predetermined packet from the RX.

[0547] When the first current value is greater than the threshold value, the TX evaluates that the possibility of the presence of a foreign object is high. In addition, the TX calculates the increase rate of the current value based on the first current value obtained at the predetermined timing.

[0548] When the increase rate of the current value is greater than the threshold value, the TX evaluates that the possibility of the presence of a foreign object is high. The evaluation result is reported to the RX using a predetermined packet. Alternatively, when the evaluation result is obtained, the TX performs control to limit power transmission (stop power transmission or reduce power transmission power).

[0549] The foreign object detection process based on the second current value in the RX will be described below. The RX acquires the second current value at a predetermined timing. The predetermined timing occurs for each predetermined time period that has been previously determined, or when the RX receives a predetermined packet from the TX.

[0550] When the second current value is greater than the threshold, RX evaluates that the possibility of foreign matter presence is high. In addition, RX calculates the increase rate of the current value based on the second current value obtained at a predetermined timing. When the increase rate of the current value is greater than the threshold, RX evaluates that the possibility of foreign matter presence is high.

[0551] The evaluation result is reported to TX using a predetermined packet. Alternatively, when the evaluation result is obtained, RX performs a process of sending a predetermined packet to TX to request restriction of power transmission (stopping power transmission or reducing power transmission). As described above, by measuring the first current value or the second current value, more accurate foreign matter detection can be performed based on the measurement result.

[0552] When an abnormal state of TX or RX is detected, TX and RX can perform detection through a combination of multiple foreign matter detection processes. That is, the Q value measurement method, the power loss method, the waveform attenuation method, the coupling state index measurement method, the foreign matter detection process based on temperature, and the foreign matter detection process based on the current flowing through the power transmission antenna or the power reception antenna can be combined.

[0553] The foreign matter detection process based on the coupling state index measurement method is called the first foreign matter detection process, the foreign matter detection process based on the temperature of TX is called the second foreign matter detection process, and the foreign matter detection process based on the current flowing through the power transmission antenna is called the third foreign matter detection process.

[0554] It is assumed that the entity that executes the first to third foreign matter detection processes is TX. In this case, TX executes the foreign matter detection process selected from the first to third foreign matter detection processes and reports the foreign matter evaluation result to RX. When the foreign matter evaluation result is "high possibility of foreign matter presence" or "foreign matter present", RX reports a packet to TX to request execution of a predetermined foreign matter detection process.

[0555] The predetermined foreign matter detection process is a foreign matter detection process based on one or more of the Q value measurement method, the power loss method, and the waveform attenuation method. TX executes the predetermined foreign matter detection process according to the execution request from RX and reports the foreign matter evaluation result to RX.

[0556] When the foreign matter evaluation result is "high possibility of foreign matter presence" or "foreign matter present", RX sends a packet to request restriction of power transmission or a packet to request the above-mentioned RECAL process to TX. The packet to request restriction of power transmission or the packet to request the above-mentioned RECAL process (hereinafter, these packets will be referred to as restriction request packets) are, for example, a packet to request setting the GP value to a lower value, or RP1 or RP2 to request the RECAL process of the power loss method.

[0557] Alternatively, the packet is a packet for requesting a RECAL process of the waveform attenuation method or a RECAL process of the coupling state index measurement method. Alternatively, the packet is an EPT packet for requesting power supply interruption.

[0558] Alternatively, the TX performs a foreign object detection process based on one or more of the Q-value measurement method, the power loss method, and the waveform attenuation method, and reports the foreign object evaluation result to the RX. When the foreign object evaluation result is "high possibility of foreign object presence" or "foreign object present", the RX sends a packet to the TX for requesting to perform a foreign object detection process selected from the first to the third foreign object detection processes.

[0559] The TX performs any one or more of the first to the third foreign object detection processes according to the packet, and reports the foreign object evaluation result to the RX. When the foreign object evaluation result is "high possibility of foreign object presence" or "foreign object present", the RX sends a restriction request packet to the TX.

[0560] In addition, the foreign object detection process based on the temperature of the RX is called the fourth foreign object detection process, and the foreign object detection process based on the current flowing through the power receiving antenna is called the fifth foreign object detection process. It is assumed that the entity performing the first, fourth, and fifth foreign object detection processes is the RX.

[0561] In this case, the RX performs a foreign object detection process selected from the first, fourth, and fifth foreign object detection processes, and reports the foreign object evaluation result to the TX. When the foreign object evaluation result is "high possibility of foreign object presence" or "foreign object present", the RX reports a packet for requesting to perform a predetermined foreign object detection process to the TX.

[0562] The predetermined foreign object detection process is a foreign object detection process based on one or more of the Q-value measurement method, the power loss method, and the waveform attenuation method. The TX performs the predetermined foreign object detection process according to the request from the RX, and reports the foreign object evaluation result to the RX.

[0563] When the judgment result of the foreign object detection process is "high possibility of foreign object presence" or "foreign object present", the RX sends a restriction request packet to the TX.

[0564] Alternatively, the TX performs a foreign object detection process based on one or more of the Q-value measurement method, the power loss method, and the waveform attenuation method, and reports the foreign object evaluation result to the RX. It is assumed that the foreign object evaluation result is "high possibility of foreign object presence" or "foreign object present".

[0565] In this case, the RX acquires a coupling state index, a temperature detection value of the RX, or a current value flowing through the power receiving antenna of the RX, performs foreign object detection processing, and reports the foreign object evaluation result to the TX. When the foreign object evaluation result is "high possibility of foreign object presence" or "foreign object present", the RX sends a restriction request packet to the TX.

[0566] In the above example, the TX or the RX performs the first foreign object detection processing, the second foreign object detection processing, or the fourth foreign object detection processing, the third foreign object detection processing, or the fifth foreign object detection processing, and other foreign object detection processing at different times. The other foreign object detection processing is foreign object detection processing based on one or more of the Q-value measurement method, the power loss method, and the waveform attenuation method.

[0567] Not limited to this example, the TX or the RX may perform the first foreign object detection processing, the second foreign object detection processing, or the fourth foreign object detection processing, the third foreign object detection processing, or the fifth foreign object detection processing, and other foreign object detection processing simultaneously.

[0568] When the RX (or TX) designates a timing, the RX (or TX) reports the timing by sending a predetermined packet to the TX (or RX). For example, when the TX (or RX) receives the predetermined packet, the TX (or RX) performs the second (or fourth) foreign object detection processing and the foreign object detection processing using the power loss method.

[0569] Alternatively, when the TX (or RX) receives the predetermined packet, the TX (or RX) performs the second (or fourth) foreign object detection processing and the foreign object detection processing using the waveform attenuation method.

[0570] Alternatively, when the TX (or RX) receives the predetermined packet, the TX (or RX) performs the second (or fourth) foreign object detection processing, the foreign object detection processing using the power loss method, and the foreign object detection processing using the waveform attenuation method. Regarding the foreign object detection processing, any combination is possible, and the combination can be changed according to the setting details such as predetermined conditions.

[0571] In addition, in the above example, the restriction request packet is defined as "a packet for requesting restriction of power transmission or a packet for requesting the above RECAL processing". Not limited to this, the above restriction request packet may be interpreted as two packets: "a packet for requesting restriction of power transmission and a packet for requesting RECAL processing".

[0572] In this embodiment, any one of the above-described multiple foreign object detection processes is executed as a state detection process based on a physical quantity measurement process (CAL process) related to the power transmission device. Based on the information acquired during the first state detection and the information obtained during the second state detection (which is based on the measurement process executed after the measurement process executed during the first state detection), it is determined whether to limit power transmission or execute the RECAL process.

[0573] It is assumed that the power transmission device has determined that the power receiving device needs to request the power transmission device to execute the RECAL process. In this case, the power transmission device sends the detection results related to the first state detection or the second state detection and the information related to the execution request of the RECAL process to the power receiving device. According to this embodiment, in the wireless power transmission from the power transmission device to the power receiving device, more appropriate control can be executed based on multiple state detection results.

[0574] [Second Embodiment]

[0575] The second embodiment will be described below. In the first embodiment, the Q-value measurement method, the power loss method, the waveform attenuation method, the coupling state index measurement method, the foreign object detection method based on temperature, and the foreign object detection method based on the current flowing through the power transmission antenna or the power receiving antenna have been described.

[0576] The "state detection method" of the present disclosure refers to these methods, and any one of these methods can be used. The foreign object detection method is an example of the state detection method. "The presence of a foreign object" can be considered as "the presence of an abnormal state".

[0577] For example, in the first embodiment, the expression "detecting the presence of a foreign object" will be described as the expression "detecting an abnormal state" below. In this embodiment, the description of the same matters as in the first embodiment will be omitted, and the differences will be mainly described. The method for which the description is omitted will be the same in the embodiments described later.

[0578] Describe the operations of the TX and RX when the TX executes the state detection method and detects an abnormal state. Figure 14 It is a flowchart for explaining the operation of the TX. Figure 15 It is a flowchart for explaining the operation of the RX.

[0579] In Figure 14 The process starts in S1401, and the power of the TX is turned on in S1402. After passing through the selection stage and the Ping stage, the TX detects the RX in S1403. After passing through the I&C stage, the negotiation stage, and the calibration stage, in S1404, the TX starts to transmit power to the detected RX in the power transmission stage. Subsequently, the process proceeds to the process of S1405.

[0580] In S1405, the TX evaluates whether it has received an execution request packet for the state detection method from the RX ( Figure 15 : S1506). The execution request packet will be described later. When the TX has not received the execution request packet ("No" in S1405), the TX continues to supply power and repeatedly executes the evaluation process in S1405. In addition, when the TX has received the execution request packet ("Yes" in S1405), the TX proceeds to the process in S1406.

[0581] In S1406, the TX executes the state detection method, measures a physical quantity related to the TX, and compares the measurement result with a threshold value to evaluate whether there is a state abnormality. For example, when the TX executes the state detection method, the TX evaluates the possibility (probability) of a state abnormality step by step. The following shows the evaluation results.

[0582] · <State 1>: A state in which the physical quantity measured by the TX is significantly lower than the threshold value and "the probability of a state abnormality is very low".

[0583] · <State 2>: A state in which the physical quantity measured by the TX is slightly lower than the threshold value and "the probability of a state abnormality is low".

[0584] · <State 3>: A state in which the physical quantity measured by the TX is slightly greater than the threshold value and "the probability of a state abnormality is high".

[0585] · <State 4>: A state in which the physical quantity measured by the TX is significantly greater than the threshold value and "the probability of a state abnormality is very high".

[0586] In this example, if the physical quantity measured by the TX is greater than the threshold value, it is evaluated that there is a possibility of a state abnormality.

[0587] In another example, if the physical quantity measured by the TX is lower than the threshold value, it is evaluated that there is a possibility of a state abnormality. The following shows the evaluation results.

[0588] · <State 1>: A state in which the physical quantity measured by the TX is significantly greater than the threshold value and "the possibility of a state abnormality is very low".

[0589] · <State 2>: A state in which the physical quantity measured by the TX is slightly greater than the threshold value and "the possibility of a state abnormality is low".

[0590] · <State 3>: A state in which the physical quantity measured by the TX is slightly lower than the threshold value and "the possibility of a state abnormality is high".

[0591] · <State 4>: A state in which the physical quantity measured by the TX is significantly lower than the threshold value and "the possibility of a state abnormality is very high".

[0592] Assume that <State 3> and <State 4> in this example are as follows: The physical quantity measured by TX is outside the threshold-based range and it is evaluated that there is a possibility of a state anomaly, but power transmission from TX to RX can be performed.

[0593] In S1407 after S1406, as a result of executing the state detection method, TX evaluates whether there is a possibility of a state anomaly. When TX evaluates that there is no possibility of a state anomaly or the possibility of a state anomaly is low ("No" in S1407), the process of TX proceeds to the process of S1405, and TX continues to transmit power to RX.

[0594] For example, the case where it is evaluated that "the possibility of a state anomaly is low" is the case where <State 1> or <State 2> is detected. On the other hand, when it is evaluated that there is a possibility of a state anomaly ("Yes" in S1407), TX proceeds to the process of S1408. For example, the case where it is evaluated that there is a "possibility of a state anomaly" is the case where <State 3> or <State 4> is detected.

[0595] In S1408, TX sends a packet for requesting permission for reporting information (communication) to RX, or in S1408, TX sends a packet for requesting attention to RX.

[0596] For example, the packet is a response (ATN) defined in the WPC standard. When RX receives the ATN sent by TX, RX sends a packet that permits the transmission of a data packet to TX.

[0597] Alternatively, when RX receives the ATN sent by TX, RX sends a packet for requesting the transmission of a data packet to TX. Specifically, the packet is a DSR / poll packet or a DSR / poll data packet determined in the WPC standard.

[0598] In S1409, TX evaluates whether TX has received a DSR / poll packet or a DSR / poll data packet from RX. When TX has not received a packet from RX ("No" in S1409), TX continues power transmission and repeatedly executes the evaluation process of S1409. In addition, when TX has received a packet from RX ("Yes" in S1409), TX proceeds to the process of S1410.

[0599] In S1410, TX sends a state detection result packet to RX. The state detection result packet is a packet including information for indicating the result of the state detection method executed by TX. For example, TX reports the following first information related to the state detection method included in the state detection result packet to RX.

[0600] · Information for indicating which state detection method has been executed.

[0601] · Information indicating the possibility of a status anomaly.

[0602] · Index information showing the result of comparing the measured physical quantity with a threshold value (e.g., any one of <Status 1> to <Status 4>).

[0603] As status detection methods, there are a Q - value measurement method, a power loss method, a waveform attenuation method, a coupling - state index measurement method, a foreign - object detection method based on temperature, and a foreign - object detection method based on the current flowing through a power - transmitting antenna or a power - receiving antenna.

[0604] The first information includes information indicating which of these status detection methods is used to perform status detection. In addition, as a result of status detection by the status detection method, the first information includes index information indicating the possibility of a status anomaly. It can also be considered that the index information is the information obtained by comparing the measured physical quantity and the threshold value.

[0605] Subsequently, in S1411, the TX sends a RECAL processing request packet to the RX. The RECAL processing request packet is a packet including information for requesting RECAL processing. For example, the TX reports the following second information related to the RECAL processing request included in the RECAL processing request packet to the RX.

[0606] · Information indicating whether to request the execution of RECAL processing for the power loss method.

[0607] · Information indicating whether to request the execution of RECAL processing for the waveform attenuation method.

[0608] · Information indicating whether to request the execution of RECAL processing for the coupling - state index measurement method.

[0609] · Information indicating the type of RECAL processing that requests the execution of the power loss method, the waveform attenuation method, or the coupling - state index measurement method.

[0610] Here, the "type of RECAL processing" refers to the following first RECAL processing or second RECAL processing.

[0611] · First RECAL processing

[0612] Discard the existing calibration points or the line segments for which interpolation processing has been performed between calibration points. The RX sends RP1 and RP2 to the TX again, and the TX creates new calibration points or creates line segments for which interpolation has been performed between calibration points.

[0613] · Second RECAL processing

[0614] Maintain the existing calibration points or the line segments where interpolation has been performed between the calibration points. The RX sends RP2 to the TX, and the TX adds a new calibration point to the existing calibration points or the line segments where interpolation has been performed between the calibration points.

[0615] For example, assume that the TX executes a state detection method and the evaluation is "high possibility of abnormal state" or "very high possibility of abnormal state".

[0616] Regarding the calibration points generated in the CAL process executed in the state of "low possibility of abnormal state" or the line segments where interpolation has been performed between the calibration points, due to the occurrence of an abnormal state, there may be a deviation.

[0617] Therefore, depending on the possibility of an abnormal state, it may be necessary to execute the RECAL process in some cases. Thus, the second information includes information related to whether to request the execution of the RECAL process. In addition, the second information includes information for indicating which state detection method is used for the RECAL process.

[0618] Subsequently, in S1412, the TX receives an execution request packet for the RECAL process from the RX. The execution request packet is, for example, RP1 and RP2. In S1413, the TX executes the RECAL process based on the information in the received execution request packet for the RECAL process.

[0619] The variable of the counter that counts the number of times the RECAL process has been executed is represented by A. In S1414, the TX increments (increases) the value of the variable A by 1. In addition, the process proceeds to the process of S1415.

[0620] In S1415, the TX evaluates whether the value of the variable A of the counter is equal to or greater than a predetermined number (threshold). As an evaluation result, when it is evaluated that the value of the variable A is equal to or greater than the predetermined number ("yes" in S1415), the TX proceeds to the process of S1416.

[0621] In addition, when it is evaluated that the value of the variable A is less than the predetermined number ("no" in S1415), the process proceeds to S1405, and the TX continues to supply power to the RX. In S1416, the TX executes control to limit the power supply (the RX executes control to limit the received power), and ends the series of processes of S1417.

[0622] The following will refer to Figure 15 to illustrate the operation of the RX. The process starts in S1501, and the power of the RX is turned on in S1502. If the RX is placed on the TX in S1503, after passing through the selection stage and the Ping stage, the RX is detected by the TX.

[0623] After the I&C phase, the negotiation phase, and the calibration phase, in S1504, the RX starts receiving power transmitted from the TX in the power transmission phase.

[0624] Subsequently, in S1505, the RX determines whether to request the TX to execute the status detection method. When a predetermined condition is satisfied (being "Yes" in S1505), the RX determines to request the TX to execute the status detection method and proceeds to the process of S1506.

[0625] On the other hand, when the predetermined condition is not satisfied (being "No" in S1505), the RX determines not to request the TX to execute the status detection method, continues to receive power, and repeatedly executes the process of S1505.

[0626] Here, the "predetermined condition" in S1505 will be described. This condition can include, for example, the TX or the RX detecting one or more of the following items.

[0627] · An error occurs in the communication between the TX and the RX.

[0628] · A decrease in the power transmission from the TX to the RX is observed.

[0629] · An outlier in the calibration data obtained.

[0630] · An increase in temperature in the TX and the RX is observed.

[0631] · There is a high possibility of a status anomaly in the status detection method.

[0632] · The RX receives information from the TX indicating a high possibility of a status anomaly in the status detection method.

[0633] Alternatively, the "predetermined condition" refers to the following situations.

[0634] · The case where the power transmission from the TX to the RX increases or decreases.

[0635] · The case where information (set value) related to the power transmission of the TX or information (set value) related to the power reception of the RX held by the TX or the RX changes.

[0636] · The case where a measurement process (CAL process) for setting a threshold value used when executing the status detection method is performed.

[0637] · The case where the RX reports the status of the RX (e.g., the received power received by the RX, etc.) to the TX.

[0638] The above-mentioned "predetermined conditions" are preset in the RX. When one or more of the set "predetermined conditions" are satisfied, the RX determines that the status detection is to be performed. As the "predetermined conditions", conditions based on matters other than those exemplified may be set, or any conditions may be set.

[0639] The timing for executing the status detection method may be determined by the TX instead of the RX, and the status detection method may be executed at an appropriate time. The TX may execute the status detection method at an appropriate time when the "predetermined conditions" are satisfied.

[0640] In S1506, the RX sends an execution request packet for the status detection method to the TX and proceeds to the process of S1507. In addition, in S1507, the RX evaluates whether it has received the ATN from the TX ( Figure 14 : S1408).

[0641] When the RX receives the ATN from the TX (yes in S1507), the RX proceeds to the process of S1508. When the RX does not receive the ATN from the TX (no in S1507), the RX continues to be powered on and repeatedly executes the evaluation process in S1507 until the ATN is received.

[0642] In S1508, the RX sends a packet (DSR / polling packet or DSR / polling data packet) that permits the TX to send data packets.

[0643] In S1509, the RX evaluates whether the RX has received a status detection result packet from the power supply device ( Figure 14 : S1410). When it is evaluated in S1509 that the RX has received a status detection result packet from the TX, the RX proceeds to the process of S1510.

[0644] When it is evaluated that the status detection result packet has not been received, the evaluation process in S1509 is repeatedly executed until the packet is received. In S1510, the RX evaluates whether the RX has received a RECAL process request packet from the TX ( Figure 14 : S1411).

[0645] When it is evaluated in S1510 that the RX has received a RECAL process request packet from the TX, the RX proceeds to the process of S1511. When it is evaluated that the RECAL process request packet has not been received, the evaluation process in S1510 is repeatedly executed until the packet is received.

[0646] In S1511, the RX sends an execution request packet for the RECAL process to the TX. In the following S1512, the RX evaluates whether the RX has received a packet for controlling the limit of the power supply power from the TX.

[0647] As a result of the evaluation of TX, when RX has received the packet from TX (yes in S1512), RX proceeds to the process of S1513. In addition, when RX has not received the packet from TX (no in S1512), RX proceeds to S1505 and continues to be powered on.

[0648] In S1513, RX performs control for restricting power transmission (control for restricting the power received by RX), and ends the series of processes of S1514.

[0649] In the present embodiment, for example, it is assumed that TX sends a status detection result packet ( Figure 14 : S1410) to RX, and then sends ATN to RX again (S1408).

[0650] In this case, when RX receives the ATN sent by TX ( Figure 15 : yes in S1507), RX sends a DSR / poll packet or a DSR / poll data packet to TX (S1508).

[0651] When TX receives the DSR / poll packet or the DSR / poll data packet (yes in S1409), TX proceeds to the process of S1411. That is, TX sends a RECAL process request packet to RX. This also applies to TX and RX in the third embodiment to be described later.

[0652] Regarding the information shown in the description related to the above first information or second information, at least one piece of information is sent from TX to RX. The first information or the second information is determined based on the information indicating the possibility of a status anomaly.

[0653] For example, when it is evaluated that there is a possibility of a status anomaly (<status 3> or <status 4>), in Figure 14 the status detection result packet sent by TX to RX in S1410 includes the following information.

[0654] · In the case of <status 3>

[0655] The first information includes information for indicating the status detection method performed and information for indicating that the status is in a state of "high possibility of status anomaly".

[0656] · In the case of <status 4>

[0657] The first information includes information for indicating the status detection method performed and information for indicating that the status is in a state of "very high possibility of status anomaly".

[0658] In addition, in Figure 14In S1411, the RECAL processing request packet sent from TX to RX includes the following information.

[0659] · In the case of <Status 3>

[0660] · The second information includes information for requesting the execution of at least one RECAL process among the RECAL processes for the power loss method, the waveform attenuation method, and the coupling state index measurement method, and information for requesting the execution of the second RECAL process.

[0661] · In the case of <Status 4>

[0662] · The second information includes information for requesting the execution of at least one RECAL process among the RECAL processes for the power loss method, the waveform attenuation method, and the coupling state index measurement method, and information for requesting the execution of the first RECAL process.

[0663] Alternatively, TX can use the same packet to send the first information and the second information to RX. Thus, when it is evaluated that "there is a status abnormality" or "the possibility of a status abnormality is high", TX and RX can quickly and appropriately execute the control corresponding to the evaluation result.

[0664] The control in the case where TX executes the status detection method multiple times and as a result obtains the evaluation results of <Status 3> or <Status 4> multiple times will be described below. As a result of the evaluation, when the status is detected as "the possibility of a status abnormality is high" or "the possibility of a status abnormality is very high" (hereinafter referred to as "the second detection status"), the RECAL process is executed.

[0665] In addition, it is assumed that TX executes the status detection method and is re-evaluated as being in the second detection status. In this case, TX executes the RECAL process again. Initially, the CAL process is a process executed when no status abnormality is detected in the first detection status.

[0666] Executing the RECAL process when the status is in the second detection status means that the CP or the line segment interpolated between CPs has changed. That is, the CP in the second detection status or the line segment interpolated between CPs replaces the ideal CP created in the CAL process or the line segment interpolated between CPs.

[0667] If the fact that the probability of a status abnormality is detected multiple times, then the RECAL process is executed multiple times. In this case, every time the RECAL process is executed, the CP in the first detection status or the line segment interpolated between CPs will deviate.

[0668] As a result, if the reliability of the CP used as a reference when performing the state detection method or the line segment obtained by interpolating between CPs decreases, it may not be possible to detect a state abnormality with high accuracy.

[0669] Therefore, when the TX needs to detect the second detection state multiple times and needs to perform the RECAL process (the first RECAL process or the second RECAL process) a predetermined number of times or more, the TX and the RX limit the power transmitted by the TX or the power received by the RX. The method for limiting the power transmitted by the TX or the method for limiting the power received by the RX are as follows.

[0670] The TX requests the execution of the RECAL process using the second information, and controls the power transmission power of the TX using predetermined information (hereinafter referred to as "third information"). The third information is information for controlling the power transmission power of the TX so that the power transmission power is equal to or less than a predetermined power value.

[0671] Alternatively, the TX controls the maximum load power value of the load that can be output (supplied) to the RX so that the maximum load power value is equal to or less than a predetermined power value. Here, the predetermined power value is, for example, 5 (watts). Alternatively, the TX sends predetermined information (hereinafter referred to as fourth information) for switching the mode of the TX or the RX to the RX. The fourth information is, for example, information for instructing a request to switch to a mode that only allows power transmission of up to 5 watts.

[0672] Alternatively, when it is necessary to perform the RECAL process a predetermined number of times or more, the TX sends a packet requesting the transmission of an EPT packet to the RX. The RX that receives this packet sends an EPT packet to the TX and ends the power transmission phase.

[0673] Alternatively, the TX detects the second detection state multiple times and requests the RX to perform the RECAL process a predetermined number of times or more. If the RX is requested to perform the RECAL process a predetermined number of times or more, the RX controls the negotiation with the TX so that the value of GP is equal to or less than a predetermined power value.

[0674] Here, the predetermined power value is, for example, 5 (watts). Alternatively, the RX may send a predetermined packet including information for requesting the TX or the RX to switch its mode to a predetermined mode to the TX. The predetermined mode is the basic power profile (BPP) mode specified by the WPC standard, and in this BPP mode, only power transmission of up to 5 watts is allowed.

[0675] Here, the meaning of setting GP to be equal to or less than 5 watts will be described. When the TX supplies power to the RX in a state where there is a foreign object between the TX and the RX, in some cases, the foreign object may generate heat.

[0676] The heat generated by a foreign object increases as the power transmitted from the TX increases. On the other hand, when the power transmitted by the TX (the power received by the RX) is limited to be equal to or less than a predetermined value, the heat generation amount can be suppressed within a predetermined range (a safe range).

[0677] In the WPC standard, even if foreign object detection is performed and there is a possibility of a foreign object being present, there are cases where, if the GP is equal to or less than 5 watts, power transmission from the TX to the RX is permitted. Thus, power transmission control can be performed with the above-mentioned predetermined power value set to 5 (watts).

[0678] For the same reason, the power transmitted by the TX is controlled to be equal to or less than 5 watts, or the maximum load power value of the output (supply) from the TX to the load of the RX is controlled to be equal to or less than 5 watts. Alternatively, when a request to perform the RECAL process a predetermined number of times or more is provided, the RX sends an EPT packet to the TX and ends the power transmission phase.

[0679] Reference will be made Figures 14 to 16 to explain the operations of the above-mentioned TX and RX. Figure 16 is a sequence diagram showing the operations of the TX and RX, with the operations of the TX shown on the left and the operations of the RX shown on the right.

[0680] In Figure 16 the example, if the power supplies of the TX and RX are turned on and the RX is placed on the TX, the phase transitions to the selection phase and the Ping phase. The TX detects the placement of the RX and starts transmitting power, and the RX starts receiving power.

[0681] After performing measurement processing (CAL processing) related to state detection, the RX requests the TX to perform a state detection method, and the TX performs the state detection method according to the execution request from the RX. When it is evaluated that there is a possibility of a state abnormality in the TX, the TX sends a packet including information related to the state detection result to the RX and sends a RECAL processing request packet.

[0682] The RX sends an execution request packet for the RECAL process to the TX. The TX performs the RECAL process according to this execution request packet.

[0683] In Figure 14 S1410 of, the TX sends a state detection result packet to the RX. When it is evaluated in S1509 that the RX has received the state detection result packet from the TX (yes in S1509), the RX proceeds to the process of S1510.

[0684] When the RX receives a RECAL processing request packet from the TX (Yes in S1510), the RX uses the second information in the RECAL processing request packet to identify that the TX requests the RX to execute the RECAL processing.

[0685] In S1511, the RX sends a RECAL processing execution request packet (RP1, RP2) to the TX. The TX that receives this execution request packet from the RX executes the RECAL processing in S1413 based on the information in the execution request packet.

[0686] In S1414, the value of variable A of the counter is incremented by 1. Additionally, when it is evaluated in S1415 that the value of variable A is equal to or greater than a predetermined number of times (Yes in S1415), in S1416, the TX executes control for restricting the power transmission or the power received by the RX.

[0687] When it is evaluated that the value of variable A is less than the predetermined number of times (No in S1415), the process proceeds to S1405 and the TX continues power transmission. When the RX receives a packet for executing control for restricting power transmission from the TX (Yes in S1512), the RX enters S1513 and executes control for restricting the power received by the RX.

[0688] In Figure 14 and Figure 15 In the flowchart of, the function of counting the number of times the RECAL processing is executed is implemented in S1413 and S1414, but this function can be implemented at other processing positions. For example, the processing from S1413 to S1415 can be executed after S1410 or S1411. Additionally, the processing from S1413 to S1415 can be executed after obtaining an affirmative ("Yes") evaluation result in S1407 (before S1408).

[0689] The reason is that even if the processing from S1413 to S1415 is executed at the above-mentioned processing positions, the TX can identify that at these points, the operations after these points will move it away from the CP without any state anomalies or the line segment where interpolation between CPs has been performed.

[0690] Here, a method for determining the GP related to the power transmission of the TX or the power reception of the RX will be described. Based on this method, control operations for restricting the power transmission are executed. There are the following methods: In the negotiation phase or the renegotiation phase, the TX and the RX negotiate to determine the GP.

[0691] The RX sends a request for load power information to the TX. The requested load power is the power that the RX requests the TX to output to the load and is the power consumed by the load of the RX.

[0692] A load refers to a system that receives power from the power receiving unit of the RX, and examples thereof include the charging unit 206 and the battery 207 of the RX. On the other hand, the TX pre - has a value of potential load power or a value of negotiable load power.

[0693] The potential load power is the maximum load power value (highest load power level) that the TX can negotiate and provide output (supply) to the load of the RX.

[0694] In addition, the negotiable load power is the maximum load power value (highest load power level) that the TX can negotiate and provide output (supply) to the RX load during a predetermined time period or under predetermined conditions.

[0695] When the requested load power value is less than the negotiable load power value, the negotiation is successful. The TX and the RX set the requested load power value as the value of the GP and hold the set value in the memory.

[0696] That is, when the TX receives the requested load power value from the RX and this value is less than the negotiable load power value, the TX sends an affirmative response ACK to the RX.

[0697] The TX and the RX set the requested load power value as the value of the GP and hold the set value in the memory. In addition, when the TX receives the requested load power value from the RX and this value is greater than the negotiable load power value, the TX sends a negative response NAK to the RX.

[0698] The RX reduces the requested load power value and sends the information indicating the requested load power value to the TX again. The RX repeatedly performs this process until the RX receives an affirmative response ACK from the TX.

[0699] If the RX receives an affirmative response ACK from the TX, the TX and the RX set the requested load power value as the value of the GP and hold the set value in the memory.

[0700] By setting the value of the GP to be equal to or less than a predetermined value, the power transmission power of the TX and the power reception power of the RX can be reduced. For this reason, the TX sets the potential load power or the negotiable load power to be equal to or less than a predetermined value.

[0701] Alternatively, the RX sets the requested load power value to be equal to or less than a predetermined value. In the present disclosure, when the TX requests the RX to reduce the power transmission power of the TX or the power reception power of the RX, the TX or the RX will perform the above operation.

[0702] Alternatively, when the RX requests the TX to reduce the power transmission power of the TX or the power reception power of the RX, the TX or the RX performs the above operation.

[0703] Furthermore, by setting the value of GP to be equal to or greater than a predetermined value, the transmitted power of TX and the received power of RX can be increased. For this reason, TX sets the potential load power or the negotiable load power to be equal to or greater than a predetermined value.

[0704] Alternatively, RX sets the value of the requested load power to a predetermined value or more. In the present disclosure, when TX requests RX to increase the transmission power of TX or the reception power of RX, TX or RX will perform the above operation.

[0705] In the state detection method, the Q value measurement method, the waveform attenuation method, the coupling state index measurement method, the foreign object detection processing based on temperature, and the foreign object detection processing based on the current flowing through the power transmission antenna are performed. The method for evaluating the possibility (probability) of the state abnormality of TX in this case will be described.

[0706] For example, it is assumed that TX performs any of the state detection methods and evaluates that TX is in <state 3> or <state 4>. In this case, TX sets a threshold value to be used in the subsequent state detection method. The threshold value is set based on the physical quantity measured when the state detection method is performed and TX is recognized to be in <state 3> or <state 4>.

[0707] That is, TX performs evaluation regarding <State 1> to <State 4> based on information regarding the deviation amount and deviation direction (positive direction or negative direction) of the physical quantity measured when TX is evaluated to be in <State 3> or <State 4>.

[0708] In this embodiment, when the state detection method is executed and it is evaluated as "high possibility of state abnormality" or "very high possibility of state abnormality", RECAL processing is executed. When RECAL processing is executed a predetermined number of times or more, control is performed to limit the transmission power of TX or the reception power of RX.

[0709] [Third embodiment]

[0710] The third embodiment will be described below. In this embodiment, when TX executes the state detection method and evaluates at least once that "the possibility of state abnormality is high" or "the possibility of state abnormality is very high", the control described in the second embodiment is executed.

[0711] After that, TX executes the state detection method again, and the control performed when the predetermined condition indicating that the device state has improved is satisfied will be described. Figure 14 , Figure 17 and Figure 18 To illustrate the operation of TX, and will refer to Figure 15 To illustrate the operation of RX.

[0712] When the TX executes the state detection method and it is evaluated as "high possibility of abnormal state" or "very high possibility of abnormal state", the TX executes the control shown in the second embodiment. The operations up to now are operations corresponding to the processes in Figure 17 S1401 to S1413 of

[0713] In Figure 15 S1505 of

[0714] the RX determines whether to request the TX to execute the state detection method. When a predetermined condition is satisfied, the RX determines that it requests the TX to execute the above-mentioned state detection method ("Yes" in S1505), and proceeds to S1506.

[0715] In Figure 17 after S1413 of Figure 18 the TX proceeds to the process of S1801 in Figure 15 and the TX evaluates whether it has received an execution request packet for the state detection method from the RX (

[0716] : S1506). When the TX receives an execution request packet for the state detection method from the RX ("Yes" in S1801), the TX proceeds to the process of S1802.

[0717] In addition, when the TX does not receive an execution request packet for the state detection method from the RX ("No" in S1801), the TX continues to supply power and repeatedly executes the evaluation process of S1801.

[0718] In S1802, the TX executes the state detection method. The timing for executing the state detection method can be determined by the TX instead of the RX. If it is evaluated that the above-mentioned predetermined condition is satisfied, the TX can execute the state detection method.

[0719] The TX measures a physical quantity related to the TX and compares the measurement result with a threshold value to evaluate whether there is an abnormal state. In this embodiment, it is assumed that: when the TX executes the state detection method, the TX gradually evaluates the possibility (probability) of an abnormal state.

[0720] In S1803, as a result of the execution state detection method, TX evaluates whether there is a possibility of a state anomaly. For example, the evaluation result of the fact that "there is a possibility of a state anomaly" corresponds to the case where the above <State 3> or <State 4> is detected.

[0721] If it is evaluated that there is a possibility of a state anomaly ( "yes" in S1803), the process transitions from Figure 18 node B in Figure 14 to the process of S1408 via node B in Figure 14 Node B in

[0722] is the node to be connected after the evaluation result in S1407 is "yes".

[0723] On the other hand, when it is determined that "there is no possibility of a state anomaly" or "the possibility of a state anomaly is low" ( "no" in S1803), the process proceeds to the process of S1804. For example, the evaluation result of "the possibility of a state anomaly is low" corresponds to the case where the above <State 1> or <State 2> is detected or the case of <State 5> described below is detected.

[0723] In S1804, TX has previously been evaluated to be in a state with a high possibility of a state anomaly, and TX evaluates whether the RECAL process has been executed. When it is previously evaluated in S1804 that the RECAL process has not been executed in a state with a high possibility of a state anomaly ( "no" in S1804), TX continues power transmission and transitions to S1801.

[0724] In addition, when it is evaluated that the RECAL process has been executed in a state with a high possibility of a state anomaly ( "yes" in S1804), the process proceeds to the process of S1805. In S1805, TX evaluates whether the following <State 5> has been detected.

[0725] <State 5> is a state that satisfies a predetermined condition for indicating that the device condition has improved. As an example, a state where a foreign object that has existed between TX and RX has been removed is provided. When it is evaluated in S1805 that <State 5> has not been detected ( "no" in S1805), TX continues power transmission and transitions to S1801.

[0726] For example, the evaluation result of " <State 5> has not been detected" corresponds to the case where the above <State 1> or <State 2> is detected. In addition, when it is evaluated that <State 5> has been detected ( "yes" in S1805), the process proceeds to the process of S1806.

[0727] The execution order of the processes of S1804 and S1805 can be reversed. When the RECAL process has been executed in a state with a high possibility of a state anomaly in the past, a CP is created or an interpolation is performed between CPs for the line segment.

[0728] Therefore, for example, when it is evaluated in S1805 that <State 5> is detected, the RECAL process needs to be executed. The reason is that: if a CP is not created or an interpolated line segment between CPs has been performed in a state where the device conditions have improved (a state with a low possibility of state abnormality), high-accuracy state detection will no longer be possible.

[0729] The process after S1806 is a process for executing the RECAL process. In S1806, the TX sends an ATN to the RX. In Figure 15 S1507, when the RX does not receive the ATN sent by the TX ("No" in S1507), the RX continues to be powered and waits until the RX receives the ATN.

[0730] In addition, when the RX receives the ATN sent by the TX ("Yes" in S1507), the RX enters the process of S1508. In S1508, the RX sends a packet that permits the transmission of data packets to the TX.

[0731] The packet is a DSR / poll packet or a DSR / poll data packet defined by the WPC standard.

[0732] In S1807, the TX evaluates whether the TX has received the DSR / poll packet or the DSR / poll data packet sent by the RX. When the TX does not receive the packet ("No" in S1807), the TX continues to supply power and waits until the TX receives the packet.

[0733] In addition, when the TX receives the packet from the RX ("Yes" in S1807), the TX enters the process of S1808. In S1808, the TX sends a state detection result packet including information indicating the execution result of the state detection method to the RX. Subsequently, in S1809, the TX sends a RECAL process request packet including information requesting the RECAL process to the RX.

[0734] In this embodiment, when the state abnormality has been evaluated as "high possibility of state abnormality" or "very high possibility of state abnormality" at least once, the control described in the second embodiment is executed. After that, the following condition is detected: a predetermined condition for indicating that the device conditions have improved is satisfied.

[0735] This state is set to <State 5>. As an example, a state where a foreign object that has existed between the TX and the RX has been removed is provided. <State 1> and <State 2> are states that may occur even when there is a foreign object between the TX and the RX (because a CP as an evaluation threshold and an interpolated line segment between CPs have been created in a state where a foreign object already exists).

[0736] On the other hand, <State 5> corresponds to a state in which the cause of the state anomaly no longer exists (a state without a state anomaly or a state with a low possibility of a state anomaly). A method for detecting <State 5> will be described later.

[0737] When <State 5> is detected, TX sends a state detection result packet including the following first information to RX.

[0738] · The first information includes information indicating the state detection method performed and information indicating that the current state is <State 5>.

[0739] In addition, when <State 5> is detected, TX sends a RECAL processing request packet including the following second information to RX.

[0740] · The second information includes information requesting the execution of RECAL processing based on at least one of the power loss method, the waveform attenuation method, and the coupling state index measurement method, and information requesting the execution of the first RECAL processing or the second RECAL processing.

[0741] Alternatively, when <State 5> is detected, in Figure 18 S1808 of, TX may send a state detection result packet including the following first information to RX.

[0742] · The first information includes information indicating the state detection method performed and information indicating that the current state is <State 1>.

[0743] When <State 5> is detected, RX can identify that RX is in <State 5> by receiving a RECAL processing request packet and a state detection result packet including the above-mentioned predetermined information from TX.

[0744] TX can send the above-mentioned first information and second information to RX using the same packet. Thus, when it is evaluated that "a state anomaly exists" or "the possibility of a state anomaly is high", TX and RX can quickly and appropriately execute the corresponding control.

[0745] At the stage where this evaluation has been performed, TX executes the control described in the second embodiment and executes RECAL processing. That is, when <State 3> or <State 4> is detected, a CP is created or a line segment interpolated between CPs is created.

[0746] After that, when <State 5> is detected, the possibility of the state being improved is high, or the possibility of the state anomaly being removed is high. Therefore, RECAL processing is executed due to the change in the state.

[0747] Since the state detection method can be performed based on the CP in a state where the possibility of state improvement or the elimination of state abnormality is high, or a line segment interpolated between CPs, more accurate state detection can be performed.

[0748] In Figure 15 RX receives the state detection result packet from TX ("Yes" in S1509) and receives the RECAL processing request packet ("Yes" in S1510). RX uses the second information in the RECAL processing request packet to identify that the execution of RECAL is being requested. In addition, RX sends an execution request packet (RP1, RP2) for the execution of RECAL processing to TX (S1511).

[0749] In Figure 18 In S1810 of

[0750] TX receives the execution request packet (RP1, RP2) for the RECAL processing from RX. In S1811, TX performs the RECAL processing based on the information in the execution request packet. In addition, in S1812, this series of processes ends.

[0751] · When the state detection method is the Q-value measurement method

[0752] Assume that TX sets a first threshold when performing the Q-value measurement method. In this case, in addition to the first threshold set for detecting state abnormality, TX also sets a new second threshold for detecting <State 5>.

[0753] When the measured value of the Q-value is greater than the second threshold, TX evaluates the state as <State 5>. Alternatively, TX stores the Q-value measured when <State 1> or <State 2> is detected in the memory. After that, TX calculates the difference between the Q-value measured when performing the state detection method and the stored Q-value.

[0754] If the value of the difference is within a predetermined value, the state is evaluated as being in <State 5> according to the value of the difference. Alternatively, TX stores the Q-value measured when <State 3> or <State 4> is detected in the memory.

[0755] After that, TX compares the Q-value measured when performing the state detection method with the stored Q-value (stored value). When the measured value of the Q-value is greater than the stored value and the difference between the measured value and the stored value is equal to or greater than the predetermined value, the state is evaluated as being in <State 5> according to the value of the difference.

[0756] · When the state detection method is the power loss method

[0757] At the stage where it is evaluated as "high possibility of abnormal state" or "very high possibility of abnormal state", the TX executes the control described in the first embodiment and executes the RECAL process.

[0758] That is, when <State 3> or <State 4> is detected, a CP or a line segment where interpolation between CPs has been performed is created, and the power loss method is executed using the threshold set based on this.

[0759] Assume that the power loss due to abnormal state (Ploss_FO) calculated by the TX is a first value when the power loss method is executed again under the above state. Assume that the power loss due to abnormal state calculated by the TX is less than a first threshold, and this first threshold is based on the power loss derived from the CP or the line segment where interpolation between CPs has been performed.

[0760] In this case, it is evaluated as <State 1> or <State 2>. Assume that the TX evaluates that there is a high possibility that the state does not change or will not change, and the TX does not send a packet including the above first information to third information to the RX.

[0761] Alternatively, when the TX detects <State 2>, the TX may request the RX to execute a state detection method different from the power loss method. In addition, assume that the power loss method is executed again under the above conditions, and the power loss due to abnormal state (Ploss_FO) calculated by the TX is a second value.

[0762] Assume that the second value is a positive value (there is power loss). Assume that the power loss due to abnormal state calculated by the TX is greater than a first threshold, and this first threshold is based on the power loss derived from the CP or the line segment where interpolation between CPs has been performed. In this case, it is evaluated as <State 3> or <State 4>, and the same control as in the second embodiment is executed.

[0763] On the other hand, when <State 5> is detected, assume that the power loss method is executed based on the threshold set in <State 3> or <State 4>. Assume that the power loss method is executed again under the above conditions, and the power loss due to abnormal state (Ploss_FO) calculated by the TX is a third value.

[0764] In this case, the threshold of the power loss method has been set in <State 3> or <State 4>. The TX executes the power loss method to calculate the power loss due to abnormal state. For example, when the current state is <State 5>, the third value may be a negative value.

[0765] The reason is that the set threshold is the threshold in <State 3> or <State 4>. That is to say, the reason is that if the power loss method is executed in <State 5>, since the state anomaly is eliminated, the power loss caused by the state anomaly calculated by the TX will decrease.

[0766] Therefore, in order to detect <State 5>, the TX uses the CP or the line segment interpolated between the CPs to set the second threshold. The second threshold is different from the first threshold, and the second threshold is smaller than the first threshold. When the value of the power loss caused by the state anomaly calculated by the TX is less than the second threshold, it is evaluated as <State 5>.

[0767] As another method, there is a method of comparing the first value with the third value and making an evaluation based on the comparison result. The first value is the value of the power loss caused by the state anomaly calculated by the TX when it is evaluated as <State 1> or <State 2>.

[0768] On the other hand, the third value is the value of the power loss caused by the state anomaly calculated by the TX when it is evaluated as <State 5>. The third value is smaller than the first value. When the difference equal to or greater than the predetermined value occurs between the third value and the first value, it is evaluated as the state being in <State 5> according to the value of the difference.

[0769] That is to say, when the TX pre-stores the first value, the power loss (Ploss_FO) caused by the state anomaly calculated when the state detection method is executed is less than the first value, and the difference equal to or greater than the predetermined value occurs, the TX evaluates that the TX is in <State 5> according to the value of the difference.

[0770] Alternatively, when the power loss (Ploss_FO) caused by the state anomaly is less than the first value and this value is negative, the TX evaluates that the TX is in <State 5> according to the value of the difference.

[0771] Alternatively, when the power loss (Ploss_FO) caused by the state anomaly is less than the first value, the difference equal to or greater than the predetermined value occurs, and this value is negative, the TX evaluates that the TX is in <State 5> according to the value of the difference.

[0772] · When the state detection method is the waveform attenuation method

[0773] Assume that the TX sets the threshold based on the fourth threshold setting method when executing the waveform attenuation method. That is to say, the threshold is determined based on the result of the CAL process of the waveform attenuation method.

[0774] In this case, the same process can be executed as in the case of the power loss method described above. The TX uses the CP or a line segment interpolated between the CPs to set a threshold for detecting <State 5>.

[0775] When the value of the waveform attenuation rate calculated by the TX (set as the Q value) is greater than the threshold, it is evaluated as <State 5>. Alternatively, the TX stores the value of the waveform attenuation rate calculated when evaluated as <State 1> or <State 2> in the memory.

[0776] After that, assume that the value of the waveform attenuation rate calculated by the TX when executing the state detection method is greater than the stored value of the waveform attenuation rate. When the difference between these values of the waveform attenuation rate is equal to or greater than a predetermined value, the state can be evaluated as being in <State 5> based on the value of the difference.

[0777] Alternatively, assume that when the TX executes the waveform attenuation method, it sets the threshold based on the first threshold setting method, the second threshold setting method, or the third threshold setting method. In addition to the first threshold set based on the first threshold setting method, the second threshold setting method, or the third threshold setting method, the TX also sets a new second threshold for detecting <State 5>.

[0778] Furthermore, when the value of the waveform attenuation rate calculated by the TX (set as the Q value) is greater than the second threshold, it is evaluated as <State 5>. Alternatively, the TX stores the value of the waveform attenuation rate calculated when evaluated as <State 1> or <State 2> in the memory.

[0779] After that, assume that the value of the waveform attenuation rate calculated by the TX when executing the state detection method is greater than the stored value of the waveform attenuation rate. When the difference between these values of the waveform attenuation rate is equal to or greater than a predetermined value, the state can be evaluated as being in <State 5> based on the value of the difference.

[0780] · Case where the state detection method is a coupling state index measurement method

[0781] Assume that when the TX executes the coupling state index measurement method, it sets the threshold based on the third threshold setting method.

[0782] This threshold is determined based on the result of the CAL process of the coupling state index measurement method. In this case, the same process can be used as in the case of the power loss method described above. The TX uses the CP or a line segment interpolated between the CPs to set a threshold for detecting <State 5>.

[0783] When the value of the coupling state index (set as the coupling coefficient) is greater than the threshold, the TX evaluates the state as <State 5>. Alternatively, the TX stores the value of the coupling state index calculated by the TX when evaluated as <State 1> or <State 2> in the memory.

[0784] After that, assume that the value of the coupling state index calculated by TX when executing the state detection method is greater than the stored coupling state index value. When the difference between these values of the coupling state index is equal to or greater than a predetermined value, the state can be evaluated as being in <State 5> based on the value of this difference.

[0785] Alternatively, when executing the coupling state index measurement method, assume that TX sets the threshold based on the first threshold setting method, the second threshold setting method, or the fourth threshold setting method. In addition to the first threshold set based on the first threshold setting method, the second threshold setting method, or the fourth threshold setting method, TX also sets a new second threshold for detecting <State 5>.

[0786] When the value of the coupling state index (set as the coupling coefficient) calculated by TX is greater than the second threshold, it is evaluated as <State 5>. Alternatively, TX stores the value of the coupling state index (set as the k value) calculated when evaluated as <State 1> or <State 2> in the memory.

[0787] After that, assume that the value of the coupling state index calculated by TX when executing the state detection method is greater than the stored coupling state index value. When the difference between these values of the coupling state index is equal to or greater than a predetermined value, the state can be evaluated as being in <State 5> based on the value of this difference.

[0788] · When the state detection method is a temperature-based foreign object detection process

[0789] Assume that TX sets the first threshold when executing the temperature-based foreign object detection process. In addition to the first threshold set for detecting an abnormal state, TX also sets a new second threshold for detecting <State 5>.

[0790] When the measured temperature value is less than the second threshold, TX evaluates that TX is in <State 5>. Alternatively, TX stores the measured temperature value when judged as <State 1> or <State 2> in the memory.

[0791] After that, assume that the difference between the measured temperature value when TX executes the state detection method and the stored temperature value is within a predetermined value. In this case, the state can be evaluated as being in <State 5> based on the value of this difference.

[0792] Alternatively, TX stores the measured temperature value when evaluated as <State 3> or <State 4> in the memory. After that, assume that the measured temperature value when TX executes the state detection method is less than the stored temperature value.

[0793] In this case, when the difference between these values of the temperature is equal to or greater than a predetermined value, it can be evaluated based on the value of the difference that the state is in <State 5>.

[0794] · The state detection method is a case of foreign object detection processing based on the current flowing through the power transmission antenna

[0795] Assume that TX sets a first threshold when performing foreign object detection processing based on the current flowing through the power transmission antenna.

[0796] In addition to the first threshold set for detecting an abnormal state, TX also sets a new second threshold for detecting <State 5>. When the value of the current flowing through the power transmission antenna measured by TX is less than the second threshold, it is evaluated as <State 5>.

[0797] Alternatively, TX stores the value of the current flowing through the power transmission antenna measured by TX when it is evaluated as <State 1> or <State 2> in a memory. After that, assume that the difference between the value of the current flowing through the power transmission antenna measured by TX when performing the state detection method and the stored current value is within a predetermined value.

[0798] In this case, TX evaluates that TX is in <State 5> based on the value of the difference. Alternatively, TX stores the value of the current flowing through the power transmission antenna measured by TX when it is evaluated as <State 3> or <State 4> in a memory.

[0799] After that, assume that the value of the current flowing through the power transmission antenna measured by TX when performing the state detection method is less than the stored current value. When the difference between these values of the current is equal to or greater than a predetermined value, TX evaluates that TX is in <State 5> based on the value of the difference.

[0800] Figure 19 is a sequence diagram showing the operations of the power transmission device and the power reception device in this embodiment. It will be described Figure 19 and Figure 16 the differences between. TX performs an initial RECAL process, and then RX determines to request TX to perform the state detection method. RX sends an execution request packet for the state detection method to TX.

[0801] TX that has received the execution request packet performs the state detection method specified by RX. Assume that TX evaluates that the possibility of a state abnormality is low. TX evaluates that the RECAL process has been performed in a state where the possibility of a state abnormality was high before the current time.

[0802] TX evaluates that <State 5> has been detected. In addition, TX sends an ATN to RX, and RX sends a DSR / poll packet or a DSR / poll data packet to TX.

[0803] TX sends a status detection result packet and a RECAL processing request packet to RX. RX sends an execution request packet for RECAL processing to TX, and TX that has received the execution request packet executes RECAL processing.

[0804] In this embodiment, when it is evaluated that "the possibility of a status anomaly is high" or "the possibility of a status anomaly is very high", the control shown in the second embodiment is executed, and then appropriate control can be executed when it is detected that the device conditions have improved.

[0805] [Application Field of the Present Disclosure]

[0806] Some (or in some cases, all) of the constituent elements in the embodiment can be replaced with other constituent components that perform other similar functions, or can be omitted, or other constituent elements can be added. In addition, the present disclosure is not limited to the WPC standard and can be applied to various standards.

[0807] In addition, the power transmission device and the power reception device can be, for example, an imaging device (such as a still camera or a video camera, etc.) or an image input device such as a scanner, and can be an image output device such as a printer, a copier, or a projector.

[0808] In addition, the device can be a storage device such as a hard disk device or a memory device, or can be an information processing device such as a personal computer (PC), a smart phone, or a tablet device.

[0809] In addition, the power reception device of the present disclosure can be an information terminal device. For example, the information terminal device has a display unit (display), and power received from the power reception antenna is supplied to the display unit (display), and the display unit (display) displays information to the user.

[0810] Power received from the power reception antenna is accumulated in a power storage unit (battery), and power is supplied from the battery to the display unit. In this case, the power reception device can have a communication unit that communicates with other devices different from the power transmission device. The communication unit can be compatible with communication standards such as NFC communication and the fifth generation (5G) mobile communication system.

[0811] In addition, the power reception device of the present disclosure can be a vehicle such as an automobile. For example, an automobile as the power reception device can receive power from a charger (power transmission device) via a power transmission antenna installed in a parking lot. In addition, an automobile as the power reception device can receive power from a charger (power transmission device) via a power transmission antenna embedded in a road.

[0812] Such a vehicle supplies the received electric power to a battery. The electric power of the battery can be supplied to a drive unit (motor, electric unit) for driving wheels, and can be used to drive sensors for driving assistance or a communication unit for communicating with an external device.

[0813] That is to say, in this case, the power receiving device may include, in addition to wheels, a battery, a motor or a sensor driven by the received electric power, and may even include a communication unit for communicating with a device other than the power transmitting device. In addition, the power receiving device may have an accommodation part for accommodating a person.

[0814] For example, as the sensor, there are sensors for measuring the distance between vehicles and the distance between a vehicle and other obstacles. The communication unit can be compatible with, for example, the Global Positioning System (Global Positioning Satellite (GPS)).

[0815] In addition, the communication unit can be compatible with communication standards such as the fifth generation (5G) mobile communication system. In addition, the vehicle can be a bicycle or a motorcycle.

[0816] In addition, the power receiving device of the present disclosure can be a power tool or a household appliance, etc. These devices used as the power receiving device can have, in addition to a battery, a motor driven by the received electric power accumulated in the battery.

[0817] In addition, these devices can have a reporting component for reporting the remaining amount of the battery, etc. In addition, these devices can have a communication unit for communicating with other devices different from the power transmitting device. The communication unit can be compatible with communication standards such as NFC and the fifth generation (5G) mobile communication system.

[0818] In addition, the power transmitting device of the present disclosure can be an in-vehicle charger for transmitting power to a mobile information terminal device such as a smart phone or a tablet computer that supports wireless power transmission in a vehicle such as an automobile. Such an in-vehicle charger can be installed anywhere in the vehicle.

[0819] For example, the in-vehicle charger can be installed in the console of the vehicle, or can be installed in the dashboard (instrument panel), in the position between the passenger seats, in the ceiling or in the door. Here, it is best not to install the in-vehicle charger in a place that will interfere with driving.

[0820] In addition, although an in-vehicle charger has been used as an example to illustrate the power transmitting device, such a charger is not limited to a charger installed in a vehicle, and can be installed in transportation vehicles such as trains, airplanes and ships. The charger in this case can also be installed between the passenger seats, in the ceiling or in the door.

[0821] In addition, a vehicle such as an automobile including an in-vehicle charger can be a power transmission device. In this case, the power transmission device has wheels and a battery, and uses the power of the battery to supply power to a power reception device using a power transmission circuit unit or a power transmission antenna.

[0822] [Other Embodiments]

[0823] The present disclosure can also be implemented using a process for supplying a program that implements one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and causing one or more processors in a computer of the system or apparatus to read and execute the program.

[0824] In addition, the present disclosure can be implemented using a circuit (e.g., ASIC) that implements one or more functions. Further, a part of the process described in the flowchart in the present disclosure can be implemented using hardware.

[0825] For example, a dedicated circuit can be automatically generated on an FPGA from a program for implementing each step using a predetermined compiler. In addition, a gate array circuit can be formed in the same manner as an FPGA and implemented as hardware.

[0826] According to an embodiment, the power transmission device determines appropriate control based on a plurality of state detection results and reports a plurality of information related to the control to the power reception device, so that the power transmission device and the power reception device can perform more appropriate control.

[0827] This application claims the benefit of Japanese Patent Application No. 2022-191548, filed on Nov. 30, 2022. The entire content of the above Japanese patent application is incorporated herein by reference.

Claims

1. A power transmission device, comprising: A power transmission component configured to wirelessly transmit power to a power receiving device using a power transmission antenna; A communication component configured to communicate with the power receiving device; A detection component configured to perform measurement processing on a physical quantity related to the power transmission device and to perform state detection of the power transmission device; And A control component configured to control the power transmission component and to perform control related to the measurement processing, wherein, when the power receiving device determines, based on information obtained during a first state detection performed based on the measurement processing and information obtained during a second state detection performed based on a measurement processing performed after the measurement processing, that it requests the power transmission device to perform the measurement processing again, the control component performs control to use the communication component to send a signal to the power receiving device, the signal including information related to a state detection result related to the first state detection or the second state detection and a signal including information related to the request to perform the measurement processing again.

2. The power transmission device according to claim 1, wherein When it is determined, during the state detection, that there is a possibility of a state abnormality related to the power transmission device, the control component performs control to use the communication component to send a signal to the power transmission device, the signal including a first piece of information for indicating a state detection result and a second piece of information for the power receiving device to request the power transmission device to perform the measurement processing again, and when the communication component receives an execution request for requesting the measurement processing again from the power receiving device, the control component performs control to perform the measurement processing again.

3. The power transmission device according to claim 2, wherein, The control component counts the number of times the measurement processing is performed again, and when the number is equal to or greater than a threshold, performs control to limit the power transmission using the power transmission component.

4. The power transmission device according to claim 3, wherein, In the control for limiting the power transmission of the power transmission device, the control component controls the power transmission power of the power transmission device or the power reception power of the power receiving device to be equal to or less than a predetermined value, or sends a signal to the power transmission device to request the power receiving device to send a request to stop power transmission.

5. The power transmission device according to any one of claims 1 to 4, wherein, When it is determined, by comparing the physical quantity measured using the detection component with a threshold, that there is a possibility of a state abnormality related to the power transmission device, the control component performs control to use the communication component to send a signal to the power receiving device, the signal including information for requesting the power receiving device to send an execution request for requesting the measurement processing again to the power transmission device.

6. The power transmission device according to any one of claims 1 to 4, wherein, In a case where it is determined that the possibility of a state abnormality related to the power transmission device is low by comparing the physical quantity measured using the detection component with a threshold value, or in a case where a state in which there is a possibility of a state abnormality related to the power transmission device transitions to a state where the possibility of a state abnormality is small or there is no possibility of a state abnormality, and in a case where the measurement process has been executed again in a state where the possibility of a state abnormality related to the power transmission device is high, the control component controls to use the communication component to send a signal including the following information to the power receiving device, and this information is used to request the power receiving device to send an execution request for requesting the measurement process to be executed again to the power transmission device.

7. The power transmission device according to claim 1, wherein, The detection component executes a plurality of state detection methods among the following state detection methods: a state detection method based on a quality factor related to the power transmission antenna, a state detection method based on the difference between the power transmission power value and the power reception power value, a state detection method based on an index indicating the attenuation of the power transmission waveform using the power transmission device, a state detection method based on an index indicating the electromagnetic coupling state between the power transmission antenna and the power reception antenna owned by the power receiving device, a state detection method based on the temperature of the power transmission device or the power receiving device, and a state detection method based on the current flowing through the power transmission antenna or the power reception antenna.

8. The power transmission device according to claim 7, wherein, After executing any one of the state detection methods and using the communication component to send a signal including information related to the state detection result to the power receiving device, the control component controls to use the communication component to send a signal including the following information to the power receiving device, and this information is used to request the power receiving device to send an execution request for requesting the measurement process to be executed again to the power transmission device.

9. A power receiving device, comprising: A power receiving component for wirelessly receiving power from the power transmission device according to claim 1 using a power receiving antenna; A communication component for communicating with the power transmission device; And A control component for controlling the power receiving component.

10. The power receiving device according to claim 9, wherein, In a case where the communication component receives a signal including information related to the state detection result and a signal including information related to an execution request for re-executing the measurement process, the control component controls to use the communication component to send an execution request for requesting the power transmission device to re-execute the measurement process to the power transmission device.

11. A wireless power transmission system, comprising a power transmission device and a power receiving device, Among them, The power transmission device includes: A power transmission component for wirelessly transmitting power to the power receiving device using a power transmission antenna; A first communication component for communicating with the power receiving device; A detection component for executing a measurement process for a physical quantity related to the power transmission device and performing state detection of the power transmission device; and A first control component for controlling the power transmission component and performing control related to the measurement process, The power receiving device includes: A power receiving component for wirelessly receiving power from the power transmission device using a power receiving antenna; A second communication component for communicating with the power transmission device; and A second control component for controlling the power receiving component, When the power receiving device determines, based on the information obtained when performing the first state detection based on the measurement process and the information obtained when performing the second state detection based on the measurement process performed after the measurement process, that it requests the power transmission device to perform the measurement process again, the first control component performs control to use the first communication component to send a signal including information related to the state detection result related to the first state detection or the second state detection and a signal including information related to the request to perform the measurement process again to the power receiving device, and When the communication component receives a signal including information related to the state detection result and a signal including information related to the execution request to perform the measurement process again, the second control component performs control to use the second communication component to send an execution request to the power transmission device to request the power transmission device to perform the measurement process again.

12. A control method performed in a power transmission device for wirelessly transmitting power to a power receiving device, the control method of the power transmission device comprising: A step of using a power transmission component to wirelessly transmit power to the power receiving device using a power transmission antenna; A step of using a communication component to communicate with the power receiving device; A detection step of performing a measurement process on a physical quantity related to the power transmission device and performing a state detection of the power transmission device using a detection component; And A control step of using a control component to perform control of the power transmission component and control related to the measurement process, wherein, in the control step, when the power receiving device determines, based on the information obtained when performing the first state detection based on the measurement process and the information obtained when performing the second state detection based on the measurement process performed after the measurement process, that it requests the power transmission device to perform the measurement process again, the control component performs control to use the communication component to send a signal including information related to the state detection result related to the first state detection or the second state detection to the power receiving device and send a signal including information related to the request to perform the measurement process again to the power receiving device.

13. A storage medium for storing a computer program, the computer program being configured to cause a computer of a power transmission device for wirelessly transmitting power to a power receiving device to perform each of the following steps, the steps including: A step of using a power transmission component to wirelessly transmit power to the power receiving device using a power transmission antenna; A step of using a communication component to communicate with the power receiving device; A detection step of performing a measurement process on a physical quantity related to the power transmission device and performing a state detection of the power transmission device using a detection component; And A control step of using a control component to perform control of the power transmission component and control related to the measurement process, Among them, in the control step, control is executed such that when the power receiving device determines to request the power sending device to execute the measurement process again based on the information obtained when executing the first state detection based on the measurement process and the information obtained when executing the second state detection based on the measurement process executed after the measurement process, the communication component is used to execute sending a signal including information related to the state detection result related to the first state detection or the second state detection to the power receiving device and sending a signal including information related to the request to execute the measurement process again to the power receiving device.

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