Power transmission equipment, power receiving equipment, methods performed by power transmission equipment, methods performed by power receiving equipment, and programs

Abstract

This invention provides a technology for appropriately determining the state between power transmission equipment and power receiving equipment. [Solution] A power transmission device according to one aspect of the present disclosure is a power transmission device that wirelessly transmits power to a power receiving device, and is characterized by having a receiving means for receiving first information from the power receiving device regarding the distance between a power receiving coil having the power receiving device and an enclosure having the power receiving device that encloses the power receiving coil, and a processing means for performing specific processing based on the first information.

Description

[Technical Field]

[0001] This disclosure relates to power transmission equipment, power receiving equipment, methods performed by power transmission equipment, methods performed by power receiving equipment, and programs. [Background technology]

[0002] Patent Document 1 discloses a power transmission device that improves the accuracy of detecting metallic foreign objects by detecting the state of electromagnetic coupling with the secondary coil based on a correction value, thereby suppressing the influence of the metal casing of a portable device or the like, which is the receiving side (secondary side). Hereinafter, the state of electromagnetic coupling will also be referred to as the electromagnetic coupling state or simply the coupling state. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2012-244732 [Overview of the project] [Problems that the invention aims to solve]

[0004] The distance between the transmitting coil and the receiving coil affects the detection (or determination) of the coupling state between the power transmitting device and the power receiving device, as well as the detection of whether foreign matter is present between the power transmitting device and the power receiving device. Therefore, in the conventional technology described above, if the coefficients (correction values) used for coupling state detection and foreign matter detection are not determined based on the distance between the transmitting coil and the receiving coil, it may not be possible to properly determine the state between the power transmitting device and the power receiving device.

[0005] In view of the foregoing, one aspect of this disclosure provides a technology for appropriately determining the state between a power transmission device and a power receiving device. [Means for solving the problem]

[0006] A power transmission device according to one aspect of the present disclosure is a power transmission device that wirelessly transmits power to a power receiving device, and is characterized by comprising: a receiving means for receiving first information from the power receiving device regarding the distance between a power receiving coil having the power receiving device and an enclosure having the power receiving device that encloses the power receiving coil; and a processing means for performing specific processing based on the first information. [Effects of the Invention]

[0007] According to one aspect of this disclosure, the state between the power transmission device and the power receiving device can be appropriately determined. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram showing an example configuration of a wireless charging system according to the first embodiment. [Figure 2] This is a functional block diagram showing an example configuration of a power transmission device according to the first embodiment. [Figure 3] This is a functional block diagram showing an example configuration of a power receiving device according to the first embodiment. [Figure 4] This diagram illustrates the threshold setting method for state detection using the Power Loss method. [Figure 5] This is a diagram explaining the Q-value measurement method. [Figure 6] This is a block diagram showing an example of the functional configuration of the control unit of a power transmission device according to the first embodiment. [Figure 7] This flowchart shows an example of processing in a power transmission device. [Figure 8] This is a flowchart showing an example of processing by a power receiving device. [Figure 9] This diagram illustrates the distance between the antenna (coil) and the enclosure. [Figure 10] This is a conceptual diagram of the information held in the memory of the power transmission device according to the embodiment. [Figure 11] This figure shows an example of the format of an ID packet transmitted by a power receiving device according to this embodiment. [Figure 12] This is a flowchart showing an example of processing by a power transmission device according to the embodiment. [Figure 13] This is a flowchart showing an example of processing by a power receiving device according to the embodiment. [Figure 14] This is a sequence diagram showing an example of processing for a power receiving device and a power transmitting device according to an embodiment. [Modes for carrying out the invention]

[0009] The embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. Although the embodiments describe several features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the accompanying drawings, the same or similar configurations are given the same reference numeral. Each embodiment shows a wireless charging system to which a wireless power transmission system is applied. As an example, wireless power transmission based on the standards formulated by the Wireless Power Consortium (WPC), a standardization organization for wireless charging (hereinafter referred to as the WPC standard), will be described. An example of a WPC standard is the Qi standard.

[0010] [First Embodiment] This embodiment will be described with reference to the drawings. Figure 1 is a diagram showing an example of the configuration of a wireless charging system according to the first embodiment. This wireless charging system comprises a power transmission device 100, a power receiving device 200, and a charging cradle (Interface Surface) 300.

[0011] In the following, for the sake of brevity, the power receiving device 200 may be referred to as RX200 and the power transmitting device 100 as TX100. The detailed configurations of TX100 and RX200 will be described later using Figures 2 and 3.

[0012] The RX200 is an electronic device that receives power wirelessly from the TX100 and charges its internal battery when placed on the charging cradle 300. The TX100 is an electronic device that wirelessly transmits power to the RX200 when it is placed on the charging cradle 300. Since the charging cradle 300 constitutes part of the TX100, in the following, when the RX200 is "placed on the charging cradle 300", it may be referred to as "placed on the TX100". The spatial range in which the RX200 can receive power from the TX100 is schematically shown in Figure 1 by the area of ​​the dotted line frame 400. The RX200 and TX100 may have functions to perform applications other than wireless charging. For example, the RX200 is a smartphone, and the TX100 is an accessory device for charging the RX200's battery. However, this disclosure is not limited to this example.

[0013] Next, with reference to Figure 2, an example configuration of the power transmission device 100 will be described. Figure 2 is a functional block diagram showing an example configuration of the power transmission device 100. TX100 includes a control unit 101, a power supply unit 102, a power transmission unit 103, a first communication unit 104, a power transmission antenna (power transmission coil) 105, a memory 106, a resonant capacitor 107, a switch unit 108, a second communication unit 109, and a user interface unit 110. Hereinafter, the user interface will be referred to as UI. In Figure 2, each functional block element is shown as a separate entity, but any multiple functional block elements may be implemented as the same hardware module (for example, on the same chip).

[0014] The control unit 101 controls the entire TX100 by executing a control program stored in the memory 106. The control unit 101 also performs power transmission control, including communication for device authentication in the TX100. Furthermore, the control unit 101 can perform control for applications other than wireless power transmission. The control unit 101 is configured to include one or more processors, such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). Alternatively, the control unit 101 may be configured to include hardware such as an Application Specific Integrated Circuit (ASIC). The control unit 101 may also be configured to include an array circuit such as an FPGA (Field Programmable Gate Array) compiled to perform predetermined processing. The control unit 101 can perform processing to store information that should be stored during the execution of various processes in the memory 106, and can perform timing processing using a timer (not shown).

[0015] 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 the commercial power supply and a battery. The battery is charged by power supplied from the commercial power supply.

[0016] The power transmission unit 103 converts the DC power or AC power input from the power supply unit 102 into AC power in the frequency band used for wireless power transmission, and inputs the converted AC power to the power transmission antenna 105 to generate electromagnetic waves for the RX200 to receive power. For example, the power transmission unit 103 is equipped with an inverter and converts the DC voltage supplied by the power supply unit 102 into an AC voltage using a switching circuit in a half-bridge or full-bridge configuration. The power transmission unit 103 includes a plurality of FETs (Field Effect Transistors) that constitute a bridge and a gate driver that controls the ON / OFF state of the plurality of FETs.

[0017] The power transmission unit 103 controls the intensity of the electromagnetic waves (transmitted power) output by adjusting the voltage (transmission voltage) or current (transmission current), or both, input to the power transmission antenna 105. The strength of the electromagnetic waves (strength of the transmitted power) is controlled by the magnitude of the transmission voltage or transmission current.

[0018] Alternatively, the power transmission unit 103 controls the intensity of the electromagnetic waves it outputs (power transmission) by adjusting the voltage, current, or both input to the inverter it has. The voltage input to this inverter will be referred to as the inverter input voltage below. The current input to this inverter will be referred to as the inverter input current below. The strength of the electromagnetic waves (strength of the power transmission) is controlled by the magnitude of the inverter input voltage or inverter input current.

[0019] Alternatively, the power transmission unit 103 controls the intensity of the electromagnetic waves (transmitted power) by adjusting the voltage, current, or both output from the inverter of the power transmission unit 103. The voltage output from this inverter will be referred to as the inverter output voltage below. The current output from this inverter will be referred to as the inverter output current below. The strength of the electromagnetic waves (strength of the transmitted power) is controlled by the magnitude of the inverter output voltage or inverter output current.

[0020] The power transmission unit 103 controls the output power of AC frequency electromagnetic waves so that it can start or stop power transmission by the power transmission antenna 105 or control the intensity of the electromagnetic waves to be output, based on instruction signals from the control unit 101. The power transmission unit 103 is also assumed to have the power supply capacity to output / supply 15 watts (W) of power to the charging section of the power receiving device 200 which complies with the WPC standard.

[0021] The first communication unit 104 is connected to the control unit 101 and the power transmission unit 103, and communicates with the RX200 for power transmission control based on the WPC standard. The first communication unit 104 performs frequency shift modulation of the electromagnetic waves output from the power transmission antenna 105 and transmits information to the RX200 for communication. The first communication unit 104 also demodulates the electromagnetic waves transmitted from the power transmission antenna 105, which have been modulated by the RX200, and obtains the information transmitted by the RX200. Communication by the first communication unit 104 is performed by superimposing a communication signal on the electromagnetic waves transmitted from the power transmission antenna 105. The first communication unit 104 performs so-called in-band communication.

[0022] Memory 106 can store information regarding the status of TX100 and RX200, in addition to the control program. This information includes the transmitted power value, the received power value, etc. Information regarding the status of TX100 is acquired by the control unit 101. Information regarding the status of RX200 is acquired by the control unit of RX200 and can be received by the first communication unit 104 or the second communication unit 109, which will be described later.

[0023] The switch unit 108 is connected in parallel to the series circuit of the resonant capacitor 107 and the power transmitting antenna 105. The control unit 101 transmits a control signal to the switch unit 108 to control its ON / OFF state. The power transmitting antenna 105 is connected to the resonant capacitor 107. When the switch unit 108 is turned ON and short-circuited by the control signal from the control unit 101, the power transmitting antenna 105 and the resonant capacitor 107 form a series resonant circuit and resonate at a specific frequency fA. At this time, current flows through the closed circuit formed by the power transmitting antenna 105, the resonant capacitor 107 and the switch unit 108. On the other hand, when the switch unit 108 is turned OFF and the circuit is opened by the control signal from the control unit 101, power is supplied to the power transmitting antenna 105 and the resonant capacitor 107 from the power transmitting unit 103.

[0024] The second communication unit 109 is connected to the control unit 101 and communicates with the RX200 using a standard different from the WPC standard. For example, the second communication unit 109 communicates with the RX200 using an antenna (not shown) different from the transmitting antenna 105. Examples of communication methods used by the second communication unit 109 include wireless LAN (Local Area Network), Bluetooth® Low Energy (BLE), and NFC (Near Field Communication). For BLE, any communication method compatible with Bluetooth standard version 4.0 or later is acceptable. The frequency band used for power transmission from the transmitting antenna 105 is different from the frequency band used for communication by the second communication unit 109. The second communication unit 109 performs so-called out-of-band communication.

[0025] Regarding communication between the TX100 and the RX200, the TX100 may selectively use one of several communication standards to communicate with the RX200. For example, the following communication configurations using multiple communication standards selectively are possible. • Communication based on the first standard (WPC standard) between the first communication unit 104 of TX100 and the first communication unit 204 of RX200 (see Figure 3). • Communication based on a second standard (a standard other than the WPC standard) between the second communication unit 109 of TX100 and the second communication unit 212 of RX200 (see Figure 3).

[0026] The UI unit 110 is connected to the control unit 101 and provides various outputs to the user. These outputs include screen displays, blinking and color changes of LEDs (Light Emitting Diodes), audio output from the speaker, and vibration of the TX100 unit. The UI unit 110 is implemented using an LCD panel, speaker, vibration motor, etc.

[0027] Next, an example configuration of the power receiving device 200 will be described with reference to Figure 3. Figure 3 is a functional block diagram showing an example configuration of the power receiving device 200. The RX200 includes a control unit 201, a UI unit 202, a power receiving unit 203, a first communication unit 204, a power receiving antenna 205, a charging unit 206, a battery 207, and a memory 208. The RX200 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. In this embodiment, an example is shown in which the functional block elements in Figure 3 are individual elements, but multiple functional block elements may be realized as a single hardware module (for example, within the same chip).

[0028] The control unit 201 controls each functional block element of the RX200 by executing a control program stored in the memory 208. Furthermore, the control unit 201 can perform control for executing applications other than wireless power transmission. The control unit 201 is configured to include one or more processors such as a CPU or MPU. In addition, the control unit 201 can control the entire RX200 (for example, the entire smartphone) in cooperation with the OS (Operating System) it is running. Alternatively, the control unit 201 is configured to include hardware such as an ASIC, or array circuits such as an FPGA compiled to perform predetermined processing. The control unit 201 stores information that should be stored during the execution of various processes in the memory 208, and can also perform timing processing using a timer (not shown).

[0029] The UI unit 202 is connected to the control unit 201 and provides various outputs to the user. These outputs include screen displays, LED blinking and color changes, audio output from the speaker, and vibration of the RX200 unit. The UI unit 202 is implemented using an LCD panel, speaker, vibration motor, etc.

[0030] The power receiving unit 203 receives AC power (AC voltage and AC current) generated by electromagnetic induction based on electromagnetic waves radiated from the TX100's transmitting antenna 105 via the power receiving antenna (power receiving coil) 205. The power receiving unit 203 then converts the AC power into DC power 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 rectifier unit (rectifier, rectifier circuit) and a voltage control unit necessary for supplying power to the load in the RX200. The rectifier unit converts the AC voltage and AC current from the transmitting antenna, received via the power receiving antenna 205, into DC voltage and DC current. This DC voltage will be referred to as the rectifier unit output voltage below. This DC current will be referred to as the rectifier unit output current below. The voltage control unit converts the level of the DC voltage (rectifier unit output voltage) output by the rectifier unit to a predetermined level. The predetermined level is the DC voltage level at which the control unit 201 and the charging unit 206 can operate. The power receiving unit 203 supplies power from the charging unit 206 to the battery 207 for charging. The power receiving unit 203 is assumed to have the power supply capacity to output 15 watts (W) of power to the charging unit 206.

[0031] The first communication unit 204 communicates with the first communication unit 104 of the TX100 for power receiving control based on the WPC standard. The first communication unit 204 is connected to the power receiving antenna 205 and the control unit 201. The first communication unit 204 demodulates the electromagnetic waves input from the power receiving antenna 205 and acquires information transmitted from the TX100. The first communication unit 204 performs load modulation, amplitude modulation, or backscatter modulation on the input electromagnetic waves and superimposes a signal concerning the information to be transmitted to the TX100 onto the electromagnetic waves, thereby communicating with the TX100.

[0032] Memory 208 stores information regarding the status of TX100 and RX200, in addition to the control program. Information regarding the status of RX200 is acquired by the control unit 201. Information regarding the status of TX100 is acquired by the control unit 101 of TX100 and can be received by the first communication unit 204 or the second communication unit 212, which will be described later.

[0033] The second communication unit 212 is connected to the control unit 201 and communicates with the TX100 using a standard different from the WPC standard. For example, the second communication unit 212 communicates with the TX100 using an antenna different from the receiving antenna 205. Examples of communication methods used by the second communication unit 212 include wireless LAN, BLE, and NFC. For BLE, any communication method compatible with Bluetooth standard version 4.0 or later is acceptable. The frequency band used when receiving power with the receiving antenna 205 is different from the frequency band used by the second communication unit 212 for communication.

[0034] Regarding communication between the TX100 and the RX200, the RX200 may selectively use one of several communication standards to communicate with the TX100. For example, the following communication configurations using multiple communication standards selectively are possible. • Communication based on the first standard (WPC standard) between the first communication unit 104 of TX100 and the first communication unit 204 of RX200. • Communication between the second communication unit 109 of TX100 and the second communication unit 212 of RX200, based on a second standard (a standard other than the WPC standard).

[0035] The first switch unit 209 is located between the charging unit 206 and the battery 207 and is controlled by the control unit 201. The first switch unit 209 has the function of controlling whether or not to supply the power received by the power receiving unit 203 to the battery 207, and the function of controlling the magnitude of the load. When the first switch unit 209 is turned OFF and opened by the control unit 201, the power received by the power receiving unit 203 is not supplied to the battery 207. When the first switch unit 209 is turned ON and short-circuited by the control unit 201, the power received by the power receiving unit 203 is supplied to the battery 207.

[0036] In Figure 3, the first switch unit 209 is located between the charging unit 206 and the battery 207, but the first switch unit 209 may also be located between the power receiving unit 203 and the charging unit 206.

[0037] Alternatively, the first switch unit 209 may be positioned between the closed circuit formed by the receiving antenna 205, the resonant capacitor 211, and the second switch unit 210, and the receiving unit 203. In this case, the first switch unit 209 has the function of controlling whether or not to supply the power received by the receiving antenna 205 to the receiving unit 203.

[0038] Furthermore, although the first switch unit 209 is described as a single functional block element in the example of Figure 3, it is possible to implement the first switch unit 209 as part of the charging unit 206 or the power receiving unit 203. Moreover, this disclosure is not limited to a configuration in which the first switch unit 209 is inserted in series between the charging unit 206 and the battery 207; the first switch unit 209 may also be inserted in parallel between the charging unit 206 and the battery 207. In this case, when the first switch unit 209 is turned OFF and opened by the control unit 201, the power received by the power receiving unit 203 is supplied to the battery 207. When the first switch unit 209 is turned ON and short-circuited by the control unit 201, the power received by the power receiving unit 203 is not supplied to the battery 207.

[0039] On the input side of the power receiving unit 203, the second switch unit 210 is connected in parallel with the resonant capacitor 211. The resonant capacitor 211 is connected to the power receiving antenna 205 via the third switch unit 213. The second switch unit 210 and the third switch unit 213 are controlled by the control unit 201. The third switch unit 213 has the function of controlling whether or not to open the terminals of the power receiving antenna 205. When the control unit 201 turns the third switch unit 213 OFF, the terminals of the power receiving antenna 205 are open. When the control unit 201 turns the third switch unit 213 ON, the power receiving antenna 205 is connected to the power receiving unit 203 via the resonant capacitor 211.

[0040] When the control unit 201 turns on the third switch unit 213 and the second switch unit 210 turns on and short-circuits, the receiving antenna 205 and the resonant capacitor 211 form a series resonant circuit and resonate at a specific frequency fB. At this time, current flows through the closed circuit formed by the receiving antenna 205, the resonant capacitor 211 and the second switch unit 210, but no current flows to the receiving unit 203. On the other hand, when the second switch unit 210 turns off and the circuit is opened, the power received by the receiving antenna 205 and the resonant capacitor 211 is supplied to the receiving unit 203. Note that this disclosure is not limited to the example in Figure 3, and the second switch unit 210 may be placed between the receiving antenna 205 and the resonant capacitor 211. When the third switch unit 213 is ON and the second switch unit 210 is ON, the terminals of the receiving antenna 205 are short-circuited. Furthermore, the third switch unit 213 may be positioned between the resonant capacitor 211 and the power receiving unit 203.

[0041] In this wireless charging system, the TX100 and RX200 transmit wireless power between the transmitting antenna 105 and the receiving antenna 205 in accordance with the WPC standard. The WPC standard defines the agreed-upon load power level between the RX200 and TX100 as a value called Guaranteed Load Power (hereinafter referred to as "GP"). Load power is the power consumed by the load. For example, GP represents the power value at which the output from the RX200 to the load is guaranteed even if the coupling between the receiving antenna 205 and the transmitting antenna 105 weakens and the power transmission efficiency decreases due to a change in the relative positions of the RX200 and TX100. In this specification, the coupling state between the transmitting antenna (transmitting coil) 105 and the receiving antenna (receiving coil) 205 may also be referred to as the coupling state between the TX100 and RX200. The load of the RX200 is the charging unit 206, the battery 207, etc., and the value of GP corresponds to the power that is guaranteed to be output from the power receiving unit 203. Alternatively, the value of GP corresponds to the power that is guaranteed to be output from the rectifier unit of the power receiving unit 203. For example, let's assume that the value of GP is 5 (watts) 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 TX100 will perform power transmission control so that it can output 5 watts to the load of the RX200. Furthermore, GP is determined by negotiation between the TX100 and the RX200. Note that this disclosure is not limited to GP, and this embodiment can be applied to a configuration in which power transmission and reception are performed with power determined by negotiation between the TX100 and the RX200.

[0042] Furthermore, when transmitting power from TX100 to RX200, we consider the case where an object is present near TX100. In this case, the object is one that may affect the power transmission from TX100 to RX200, and is a different object (foreign object) from RX200. Electromagnetic waves for power transmission may affect the foreign object, potentially causing a temperature rise or destruction of the foreign object. In this disclosure, a foreign object is an object that is neither a part of the power receiving device and the product into which the power receiving device is incorporated, nor a part of the power transmitting device and the product into which the power transmitting device is incorporated, but which may generate heat when exposed to a power signal. Examples of foreign objects include paper clips and IC cards. Objects that are essential parts of the power receiving device and the product into which the power receiving device is incorporated, or the power transmitting device and the product into which the power transmitting device is incorporated, but which may unintentionally generate heat when exposed to the radio power transmitted by the power transmitting antenna, are not considered foreign objects.

[0043] The WPC standard specifies a method to suppress 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 base 300. The Power Loss method is a method of detecting foreign objects by the difference between the power transmitted by TX100 and the power received by RX200. The Q-value measurement method is a method of detecting foreign objects by the change in the Quality Factor (also called Q-factor, quality coefficient, Q value, etc.) of the power transmission antenna 105 (power transmission coil) in TX100. Alternatively, the Q-value measurement method is a method of detecting foreign objects by the change in the Quality Factor of the resonant circuit including the power transmission antenna 105 and the resonant capacitor 107 in TX100. In this disclosure, the Quality Factor of the power transmission antenna 105 and the Quality Factor of the resonant circuit including the power transmission antenna 105 and the resonant capacitor 107 are referred to as the Quality Factor related to the power transmission antenna 105. However, the foreign objects detected by TX100 are not limited to objects located on the charging base 300. TX100 can detect foreign objects located in its vicinity. For example, TX100 can detect foreign objects located within its power transmission range.

[0044] Referring to Figure 4, we will explain foreign object detection based on the Power Loss method specified in the WPC standard. In Figure 4, the horizontal axis represents the power transmitted by TX100, and the vertical axis represents the power received by RX200. On the graph line shown by the straight line segment 1002, point 1000 corresponds to the first transmitted power value Pt1 and the first received power value Pr1, and point 1001 corresponds to the second transmitted power value Pt2 and the second received power value Pr2. On the same graph line, point 1003 corresponds to the third transmitted power value Pt3 and the third received power value Pr3. The foreign objects to be detected are conductive metal pieces, etc.

[0045] First, TX100 transmits power to RX200 at a first transmission power value Pt1, and RX200 receives power at a first reception power value Pr1. Hereafter, this state will be referred to as the Light Load state. Then, TX100 holds the first transmission power value Pt1 (for example, in memory 106). At this time, RX200 performs load control so that the power received is the minimum power. Alternatively, RX200 performs load control so that the power received is within a predetermined range or below a predetermined threshold. Here, in "power within a predetermined range" or "power below a predetermined threshold," "power" refers to power that is approximately 10% of the Reference Power, which will be described later. Furthermore, RX200 may disconnect the load from the receiving antenna 205 so that the received power is not supplied to the load (charging unit 206, battery 207, etc. in Figure 3). Alternatively, RX200 may control the load so that a predetermined power is supplied to the load. This can be achieved by controlling the first switch unit 209. Subsequently, RX200 notifies TX100 of the first received power value Pr1 by transmitting a signal relating to the first received power value Pr1 to TX100. Upon receiving the signal relating to the first received power value Pr1 from RX200, TX100 calculates the power loss between TX100 and RX200. The power loss at this time is Pt1-Pr1 (=Ploss1). TX100 can generate a calibration point (hereinafter abbreviated as CP) 1000 that shows the correspondence between Pt1 and Pr1.

[0046] Next, TX100 changes the transmission power value to the second transmission power value Pt2 and transmits power to RX200, which receives power at the second received power value Pr2. Hereafter, this state will be referred to as the Connected Load state (load connected state, maximum load state). Then, TX100 holds the second transmission power value Pt2 (for example, in memory 106). At this time, RX200 performs load control so that the power it receives is the maximum power. Here, "maximum power" is a power value close to the Reference Power, which will be described later. Alternatively, RX200 performs load control so that the power it receives is within a predetermined range or above a predetermined threshold. For example, RX200 connects the receiving antenna 205 to the load so that the received power is supplied to the load. These can be achieved by controlling the first switch unit 209. Next, RX200 notifies TX100 of the second power received value Pr2 by transmitting a signal related to the second power received value Pr2 to TX100. Upon receiving the signal related to the second power received value Pr2 from RX200, TX100 calculates the power loss between TX100 and RX200. The power loss at this time is Pt2-Pr2 (=Ploss2). TX100 can then generate CP1001, which shows the correspondence between Pt2 and Pr2.

[0047] TX100 performs linear interpolation between CP1000 and CP1001 to generate line segment 1002. Line segment 1002 shows the relationship between transmitted power and received power in a state in which no foreign objects are detected in the vicinity of TX100 and RX200 (hereinafter referred to as the first detection state). Based on line segment 1002, TX100 can estimate the power value that RX200 will receive when power is transmitted at a predetermined transmitted power in the first detection state. For example, consider the case where TX100 transmits power at a third transmitted power value Pt3. In this case, TX100 can estimate the third received power value Pr3 that RX200 will receive from point 1003 on line segment 1002, which corresponds to Pt3.

[0048] As described above, based on multiple combinations of the power transmission value of TX100 and the power reception value of RX200 measured while varying the load, the power loss between TX100 and RX200 according to the load can be determined. Furthermore, by interpolation processing from multiple combinations of power transmission and reception values, the power loss between TX100 and RX200 for all loads can be estimated. The calibration process performed by TX100 and RX200 to obtain the combination of power transmission and reception values ​​is called the "Power Loss method Calibration process." The Calibration process is also abbreviated as CAL. In addition, performing the Calibration process again after it has been executed once to update or add calibration points is called the Recalibration process, and is abbreviated as ReCAL.

[0049] Let's assume that after CAL processing using the Power Loss method, TX100 actually transmits power to RX200 at the third transmission power value Pt3, and TX100 receives a signal from RX200 regarding the received power value Pr3* (is notified of the received power value Pr3*). This signal regarding the received power value Pr3* is the Received Power data packet (mode0) specified in the WPC standard, but other messages may be used. Hereafter, the Received Power data packet (mode0) will be referred to as RP0. RP0 contains the value of the received power value Pr3*. TX100 calculates Pr3-Pr3* (=Ploss_FO) by subtracting the received power value Pr3* actually notified by RX200 from the received power value Pr3 in the first detection state. Ploss_FO can be estimated as the power consumed by foreign objects if they are present in the vicinity of TX100 and RX200, i.e., power loss. Hereinafter, the state in which a foreign object is detected near the TX100 and RX200 will be referred to as the second detection state.

[0050] In the second detection state, TX100 compares the power loss Ploss_FO, which is estimated to have been consumed by the foreign object, with a predetermined threshold. If the value of the power loss Ploss_FO exceeds the threshold, TX100 can determine that a foreign object is present. Alternatively, TX100 obtains the third received power value Pr3 from RX200 in the first detection state and pre-calculates the power loss Pt3-Pr3 (=Ploss3) between TX100 and RX200.

[0051] Next, TX100 obtains the power received value Pr3* from RX200 in the second detection state and calculates the power loss Pt3-Pr3* (=Ploss3*) between TX100 and RX200 in the second detection state. Then, TX100 can estimate the power loss Ploss_FO using Ploss3*-Ploss3.

[0052] As described above, there are two methods for calculating Ploss_FO in the second detection state. • The first method for calculating Ploss_FO from Pr3-Pr3*. A second method for calculating Ploss_FO from Ploss3*-Ploss3.

[0053] This embodiment primarily describes the second method, but the contents of this embodiment can also be applied to the first method.

[0054] Next, with reference to Figure 5, we will explain foreign object detection based on the Q-value measurement method specified in the WPC standard. Figure 5(A) is a schematic circuit diagram illustrating the Quality Factor measurement method using the Q-value measurement method. The AC power supply 901 corresponds to the power supply that outputs AC power generated by the power transmission unit 103 of TX100. The power transmission antenna 902 corresponds to the power transmission antenna 105, and the capacitor 903 corresponds to the resonant capacitor 107. The power transmission antenna 902 and the capacitor 903 are connected in series. The voltage value V8 is a voltage value at a predetermined frequency generated by the power transmission unit 103 to operate the wireless power transmission system (wireless charging system). The voltage value V9 is the voltage value applied to the power transmission antenna 902. Here, it is assumed that TX100 can change the frequency related to the voltage value. Furthermore, voltage values ​​V8 and V9 are the voltage values ​​measured by TX100 when TX100 transmits Analog Ping (hereinafter referred to as "AP") or Digital Ping (hereinafter referred to as "DP") to RX200. Note that since voltage values ​​V8 and V9 are AC voltage values, their RMS values ​​may also be used.

[0055] Figure 5(B) shows an example of the measurement results of V9 / V8 against frequency, with a peak at 100 kHz. The horizontal axis is the frequency axis, and the vertical axis represents the voltage ratio "V9 / V8". Since V9 / V8 represents the Quality Factor related to the transmitting antenna 902, its value changes when an object is placed near the transmitting antenna 902. The change in Quality Factor differs depending on whether an object is placed on TX100, whether RX200 is placed on TX100, whether foreign matter (metal fragments, etc.) is placed on TX100, and whether RX200 and foreign matter are placed on TX100.

[0056] In the Negotiation phase, as defined in the WPC standard and described later, the TX100 receives a FOD Status data packet signal from the RX200. The FOD Status data packet includes the Reference Quality Factor Value and the Reference Resonance Frequency Value. The Reference Quality Factor Value is the Quality Factor that can be measured at the terminal of the power transmission antenna of the test TX100 when the RX200 is mounted on the test TX100 and no foreign objects are nearby. The Reference Resonance Frequency Value is as follows: it is the resonant frequency calculated from the inductance value that can be measured at the terminal of the power transmission antenna of the test TX100 when the RX200 is mounted on the test TX100 and no foreign objects are nearby. Using 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 actually measured V9 / V8. Alternatively, a threshold can be set based on the Reference Resonance Frequency Value. Foreign object detection is performed by comparing this threshold with the resonance frequency, which is actually determined by measuring V9 / V8.

[0057] In this embodiment, the RX200 and TX100 communicate for power transmission and reception control based on the WPC standard. The WPC standard defines multiple phases, including the Power Transfer phase in which power transmission is performed and one or more phases prior to actual power transmission. Communication for necessary power transmission and reception control is performed in each phase. For example, foreign object detection using the Power Loss method is performed in the Power Transfer phase based on data obtained in the Calibration phase. Foreign object detection using the Q-value measurement method is performed before power transmission (before Digital Ping transmission and in the Negotiation phase or Renegotiation phase).

[0058] The WPC standard includes three phases prior to power transmission: the Selection phase, the Ping phase, and the Configuration phase. In addition, there are the Negotiation phase and the Calibration phase. The processing of each phase is described below.

[0059] During the Selection phase, the TX100 intermittently transmits Analog Pings to detect when an object is placed on the TX100's charging base. Analog Ping is a short-duration power signal applied to detect the presence of an object. However, this power signal does not activate the control unit of the power receiving device. For example, it detects when an RX200 or a conductive piece is placed on the charging base. The TX100 detects either or both the voltage and / or current values ​​of the transmitting antenna 105 when the Analog Ping is transmitted. If the voltage value falls below a threshold, or the current value exceeds a threshold, the TX100 determines that an object is present and transitions to the Ping phase. Alternatively, if the Quality Factor calculated from the voltage value satisfies a predetermined condition, or if the Quality Factor calculated from the current value satisfies a predetermined condition, the TX100 determines that an object is present and transitions to the Ping phase.

[0060] In the Ping phase, TX100 transmits a Digital Ping, which has a higher power output than Analog Ping. Digital Ping is a power signal that activates the control unit of RX200, which is mounted on top of TX100. RX200 notifies TX100 of the received voltage value. In this way, TX100 recognizes that the object detected in the Selection phase is RX200 by receiving a response from RX200 that has received the Digital Ping. Upon receiving notification of the received voltage value from RX200, TX100 transitions to the Configuration phase. Also, before transmitting Digital Ping, TX100 measures the Quality Factor related to the transmitting antenna 105, for example, using Analog Ping. This measurement result is used when performing foreign object detection processing using the Q-value measurement method. Note that depending on the version of the WPC standard, the Selection phase described above may be included as part of the Ping phase and referred to as the Ping phase.

[0061] During the Configuration phase, TX100 identifies RX200 and obtains device configuration information (capability information) from RX200. RX200 transmits an ID data packet and a Configuration data packet. The ID data packet contains RX200's identifier information, and the Configuration data packet contains RX200's device configuration information (capability information). Upon receiving the ID data packet and Configuration data packet signals, TX100 responds with an acknowledgment (ACK). The Configuration phase then ends.

[0062] In the Negotiation phase, the GP value is determined based on the GP value requested by RX200 and the power transmission capacity of TX100. TX100 also receives an FOD Status data packet from RX200, which includes the Reference Quality Factor Value and Reference Resonance Frequency Value. In the Q-value measurement method, the presence or absence of foreign matter is determined based on thresholds using the Reference Quality Factor Value and Reference Resonance Frequency Value. TX100 performs foreign matter detection processing using the Q-value measurement method according to the request from RX200. Furthermore, the WPC standard specifies a method where, after transitioning to the Power Transfer phase, the same processing as the Negotiation phase is performed again at the request of RX200. The phase in which these processes are performed after transitioning from the Power Transfer phase is called the Renegotiation phase.

[0063] In the Calibration phase, the Power Loss Calibration process (hereinafter referred to as "Power Loss Calibration Process") is performed based on the WPC standard. The RX200 also notifies the TX100 of a predetermined power received value, allowing the TX100 to make adjustments for efficient power transmission. The predetermined power received value is, for example, the power received under light load conditions or connected load conditions. The power received value notified to the TX100 is used for foreign object detection processing using the Power Loss method.

[0064] In the Power Transfer phase, the TX100 and RX200 perform control for starting and continuing power transmission, error handling, and stopping power transmission upon full charge. The TX100 and RX200 perform communication processing for these power transmission and reception control operations. For example, when performing wireless power transmission based on the WPC standard, the transmitting antenna 105 and receiving antenna 205 are used, and communication is performed by superimposing signals onto the electromagnetic waves transmitted from the transmitting antenna 105 or the receiving antenna 205. The range in which communication based on the WPC standard is possible between the TX100 and RX200 is the same as the power transmission range of the TX100. Depending on the version of the WPC standard, the Calibration phase described above may also be referred to as the Power Transfer phase, as it is part of the Power Transfer phase.

[0065] Next, the functions of the control unit of TX100 will be described with reference to Figure 6. Figure 6 is a block diagram showing an example of the functional configuration of the control unit 101 of the power transmission device 100 (TX100). 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.

[0066] The communication control unit 301 performs communication control with the RX200 based on the WPC standard via the first communication unit 104, or performs communication control with the RX200 via the second communication unit 109.

[0067] The power transmission control unit 302 controls the power transmission unit 103 to control the power transmission to the RX200.

[0068] The measurement unit 303 measures the power transmitted to the RX200 via the power transmission unit 103 and measures the average transmitted power per unit time. The measurement unit 303 also measures the Quality Factor related to the power transmission antenna 105. The measurement unit 303 also measures the temperature using temperature sensors placed at multiple locations on the TX100. The measurement unit 303 also measures a quantity (e.g., coupling coefficient) that represents the electromagnetic coupling state between the power transmission antenna 105 and the power receiving antenna 205. The quantity representing the electromagnetic coupling state, such as the coupling coefficient, may also be called a coupling state index. In this specification, measuring the coupling state index and correcting the coupling state index (by correcting the coupling coefficient as described later) to obtain the corrected coupling state index may be considered as calculating or determining the coupling state between the power transmission antenna 105 and the power receiving antenna 205.

[0069] The setting unit 304 calculates and sets the threshold for foreign object detection in the Q-value measurement method and the threshold for foreign object detection in the Power Loss method using the method described above. The setting unit 304 also calculates and sets the threshold for foreign object detection or the threshold for detecting misalignment between TX100 and RX200 based on, for example, the coupling state index between the transmitting antenna 105 and the receiving antenna 205 measured by the measurement unit 303. The setting unit 304 also calculates and sets the threshold for foreign object detection or the threshold for detecting misalignment between TX100 and RX200 based on, for example, the temperature of the power transmission device measured by the measurement unit 303.

[0070] The state detection unit 305 performs state detection between the TX100 and the RX200. For example, the state detection unit 305 detects foreign objects present between the TX100 and the RX200, and also detects misalignment between the transmitting antenna 105 and the receiving antenna 205. More specifically, state detection processing is possible based on the Power Loss method, Q-value measurement method, temperature measured in the TX100, and the electromagnetic coupling state (e.g., coupling coefficient) between the transmitting antenna 105 and the receiving antenna 205. The state detection unit 305 can perform foreign object detection and misalignment detection between the transmitting antenna 105 and the receiving antenna 205 using other methods. For example, in a TX100 equipped with NFC communication functionality, the state detection unit 305 performs state detection processing using the NFC standard's peer detection function. In addition to detecting the presence or absence of foreign objects and the electromagnetic coupling state between the transmitting and receiving antennas, the state detection unit 305 can also detect changes in the state of the TX100. For example, the state detection unit 305 can detect an increase or decrease in the number of RX200s on the TX100.

[0071] The setting unit 304 sets a threshold that serves as a criterion for determining the presence or absence of foreign matter when the TX100 performs state detection. State detection can be, for example, based on the Power Loss method, the Q-value measurement method, state detection based on the temperature measured in the TX100, or state detection based on the coupling state index of the transmitting antenna 105 and the receiving antenna 205. The setting unit 304 can also set a threshold for determination necessary for state detection processing using other methods. Based on the threshold set by the setting unit 304 and the measurement results from the measurement unit 303, the state detection unit 305 can perform foreign matter detection processing and positional misalignment detection processing between the transmitting antenna 105 and the receiving antenna 205. For example, the state detection unit 305 can acquire data such as transmitted power, Quality Factor, temperature measured in the TX100, and coupling coefficient between the transmitting antenna 105 and the receiving antenna 205 as measurement results from the measurement unit 303.

[0072] The processes performed by the communication control unit 301, power transmission control unit 302, measurement unit 303, setting unit 304, and state detection unit 305 shown in Figure 6 can be implemented using programs executed by the CPU or other components of the control unit 101. Each process is executed in parallel according to an independent program, while maintaining synchronization between programs through event processing or the like. However, two or more of these processes may be incorporated into a single program.

[0073] Next, an example of the processing flow related to power transmission and reception control performed by TX100 and RX200 will be described. Figure 7 is a flowchart of an example of power transmission control processing performed by TX100. This processing is realized, for example, by the control unit 101 of TX100 executing a program read from memory 106. This processing may also be performed in response to the power being turned on to TX100, in response to the user of TX100 inputting a command to start a wireless power transmission application, or in response to TX100 being connected to a commercial power source and receiving power. This processing may also be started by other triggers.

[0074] In S1201, TX100 performs the processes defined as the Selection and Ping phases of the WPC standard and waits for RX200 to be placed. Specifically, TX100 repeatedly and intermittently transmits Analog Ping according to the WPC standard to detect objects within the power transmission range. For example, TX100 can detect when RX200 or conductive pieces are placed on the charging base 300. If TX100 detects the presence of an object within the power transmission range, it transmits a Digital Ping.

[0075] When TX100 receives a predetermined response to Digital Ping, it determines that the detected object is RX200 and that RX200 has been placed on the charging base 300. Here, the "predetermined response" is the Signal Strength (SIG) data packet transmitted by RX200. This packet includes a Signal Strength Value representing the signal strength of the signal received by RX200. The Signal Strength Value is calculated from the following parameters: the voltage output by the rectifier of the power receiving unit 203 measured by RX200 (rectifier output voltage), the voltage of the open circuit including the power receiving antenna 205 measured by RX200 (open circuit voltage), or the power received value measured by RX200.

[0076] Furthermore, before transmitting a Digital Ping, the TX100 measures the Quality Factor of the power transmission antenna 105. This measurement result is used when performing foreign object detection processing using the Q-value measurement method.

[0077] After the placement of the RX200 is detected, in S1202, the TX100 obtains (receives) identification information from the RX200 through the Configuration phase communication defined by the WPC standard. During the Configuration phase, the RX200 sends an Identification data packet (ID Packet) to the TX100. The ID Packet contains the Manufacturer Code and Basic Device ID, which are the identification information for each individual RX200, as well as information elements that can identify the version of the WPC standard it supports.

[0078] Furthermore, the RX200 sends a Configuration data packet to the TX100. The Configuration data packet contains the following capability information for the RX200. • Maximum Power Value or Reference Power, which is a value that identifies the maximum power that the RX200 can supply to a load. Information indicating whether the RX200 has the WPC standard negotiation function. • A parameter used in frequency-shifted modulation, a communication modulation method used when the TX100 transmits information to the RX200. • Information indicating whether the RX200 supports out-of-band communication functionality.

[0079] When TX100 receives the above packet from RX200, it sends an acknowledgment (ACK) to RX200, and the Configuration phase ends. Note that TX100 may obtain the identification information of RX200 by a method other than the Configuration phase communication of the WPC standard. The identification information for each RX200 may be the Wireless Power ID. Alternatively, it may be any other identification information that can identify the individual RX200, such as the Bluetooth Address (hereinafter referred to as "BD_ADDR") unique to the second communication unit 212 of RX200. Note that BD_ADDR is an 8-byte address used in BLE. BD_ADDR is a Public Address defined in the BLE standard that indicates, for example, the manufacturer of RX200 or the individual identification information of the BLE communication function (second communication unit 212). BD_ADDR may also be a Random Address.

[0080] Next, in S1203, TX100 determines the GP through negotiation with RX200 based on the request from RX200 and its own power transmission capacity. In S1203, the Negotiation phase of the WPC standard communication takes place. For example, RX200 notifies TX100 of the power value it requests by sending a Specific Request. TX100 determines whether to accept the request based on its own power transmission capacity and other conditions. If TX100 accepts the request, it sends an acknowledgment (ACK) to RX200; if it does not accept the request, it sends a negation (NACK) or NAK to RX200. The GP value determined through negotiation with RX200 will be the value requested by RX200 if TX100 accepts the request from RX200. If TX100 does not accept the request from RX200, the GP value may be a predetermined value as defined in the WPC standard (e.g., 5 watts). Furthermore, if the TX100 receives information indicating that the RX200 does not support the Negotiation phase (for example, S1302 described below), it will not perform Negotiation phase communication and will determine the GP value to a predetermined value. The predetermined value is, for example, a value specified in advance by the WPC standard (for example, 5 watts).

[0081] Furthermore, TX100 performs foreign object detection processing using the Q-value measurement method in accordance with requests from RX200. TX100 receives a FOD Status data packet from RX200. This packet includes the Reference Quality Factor Value and Reference Resonance Frequency Value mentioned above. Then, TX100 performs foreign object detection using the Q-value measurement method. This foreign object detection is performed based on the following information. • Quality Factor and resonant frequency of the transmitting antenna 105, as measured by TX100 before transmitting a Digital Ping. • A threshold value based on the Reference Quality Factor Value and Reference Resonance Frequency Value received by the TX100 from the RX200.

[0082] Next, in S1204, TX100 and RX200 perform the Calibration phase processing (CAL processing) of the WPC standard. In the Calibration phase, TX100 performs CAL processing using the Power Loss method based on the determined Reference Power value or GP value. First, RX200 transmits a signal to TX100 containing information about the power received under light load conditions (hereinafter referred to as the first reference power received information). Light load conditions include, for example, a load disconnection state, a load condition in which the power received value of RX200 is below a first threshold, or a load condition in which the power received value of RX200 is within a predetermined range (hereinafter referred to as the "first range"). In this embodiment, the first reference power received information is assumed to be 500 milliwatts (however, the first reference power received information is not limited to 500 milliwatts). The first reference power received information is information included in the Received Power data packet (mode1) specified in the WPC standard, but other messages may be used. Hereafter, Received Power data packet (mode1) will be referred to as RP1. TX100 determines whether to accept the first reference power information based on the Control Error Value contained in the Control Error (CE) data packet received from RX200. If TX100 accepts the first reference power information, it sends an acknowledgment (ACK) to RX200. If TX100 does not accept the first reference power information, it sends a negative response (NAK) to RX200.

[0083] Next, the RX200 performs processing to transmit a signal to the TX100 containing information about the power received in a load-connected state (hereinafter referred to as the second reference power received information). The load-connected state is, for example, the maximum load state, the load state in which the transmitted power value is equal to or greater than the second threshold, or the load state in which the power received by the RX200 is the maximum power. Here, "maximum power" is power close to the Reference Power. Alternatively, the load-connected state is the load state in which the power received by the RX200 falls within a predetermined range (hereinafter referred to as the "second range"). Here, the second range is a range of power values ​​higher than the first range. In this embodiment, the second reference power received information is set to 15 watts (however, the second reference power received information is not limited to 15 watts). The second reference power received information is information included in the Received Power data packet (mode2) specified in the WPC standard, but other messages may be used. Hereinafter, the Received Power data packet (mode2) will be referred to as RP2. Based on the Control Error Value contained in the Control Error (CE) data packet received from RX200, TX100 determines whether to accept the second reference power information. If TX100 accepts the second reference power information, it sends an acknowledgment (ACK) to RX200. If TX100 does not accept the second reference power information, it sends a negative response (NAK) to RX200. TX100 then sends an acknowledgment (ACK) to RX200 in response to the second reference power information and completes the CAL process.

[0084] Through the CAL processing described above, TX100 can calculate the amount of power loss between TX100 and RX200 in light-load and load-connected states based on the power transmission value of TX100 and the power reception values ​​included in the first and second reference power reception information. Furthermore, TX100 can calculate the amount of power loss between TX100 and RX200 for all power transmission values ​​that TX100 can take by performing interpolation processing between multiple power loss values. All power transmission values ​​that TX100 can take refer to any power within the range where the power reception received by RX200 in this embodiment ranges from 500 milliwatts to 15 watts. Note that the CAL processing described above is not required.

[0085] Subsequently, in S1205, TX100 transmits power until the RX200's battery 207 is fully charged. In S1205, communication of the Power Transfer phase according to the WPC standard takes place. RX200 repeatedly sends Control Error data packets (hereinafter referred to as "CE packets") to TX100 at time intervals of t_interval. t_interval is a value defined in the WPC standard, for example, 250 milliseconds. The CE packets contain a request for how much to increase or decrease the transmitted power. Based on the received CE packets, TX100 adjusts the transmitted power by controlling the current or voltage of the transmitting antenna 105. In other words, the CE packets contain parameter data for adjusting the transmitted power. By repeating this process, power transmission at the appropriate power level according to RX200's requests is performed in near real-time.

[0086] When the battery 207 is fully charged, the RX200 sends an End Power Transfer data packet (hereinafter referred to as the "EPT packet") to terminate the Power Transfer phase. The RX200 may send an EPT packet for reasons other than full charge. Also, when the Power Transfer phase is completed, the TX100 stops supplying power for charging the RX200.

[0087] Furthermore, if TX100 fails to receive the next CE packet after a time t_timeout has elapsed since the last CE packet was received, it determines that RX200 has been removed from the charging cradle 300. In this case, TX100 terminates the Power Transfer phase. t_timeout is a value defined by the WPC standard, for example, 1500 milliseconds.

[0088] The RX200 may send packets other than CE packets to the TX100 during the Power Transfer phase. For example, there is a Charge Status data packet that notifies the TX100 of the status of the RX200's battery 207. This packet contains a Charge Status Value that indicates the percentage of charge of the battery 207. When the TX100 receives the Charge Status data packet, it notifies the user of the charging status by displaying text or a diagram based on the Charge Status Value, for example, using the UI unit 110. The TX100 may receive the Charge Status data packet at any time and may notify the user at any time of its choosing.

[0089] During the Power Transfer phase, TX100 transmits power to RX200 and performs foreign object detection processing using the Power Loss method. For example, CAL processing calculates the amount of power loss between TX100 and RX200 in the first detection state during power transmission from the difference between the transmitted power value and the received power value. The calculated amount of power loss corresponds to the reference power loss when no foreign objects are present. Then, if TX100 determines that the difference between the amount of power loss between TX100 and RX200 measured during power transmission after CAL processing and the reference power loss is greater than or equal to a threshold, it determines that a second detection state has been reached.

[0090] Referring to Figure 8, an example of the processing flow related to power reception control performed by RX200 will be explained. This processing is achieved, for example, by the control unit 201 of RX200 executing a program read from memory 208.

[0091] In S1301, RX200 performs the processes defined as the Selection phase and Ping phase of the WPC standard and waits for itself to be placed on TX100. RX200 detects that it has been placed on TX100, for example, by detecting a Digital Ping from TX100.

[0092] When RX200 detects that it has been placed on TX100, in S1302 it sends a signal to TX100 containing its identification information via an ID Packet and a Configuration data packet. Note that the identification information of RX200 may be transmitted by a method other than the communication in the Configuration phase of the WPC standard. In addition, other identification information such as BD_ADDR may be used as long as it is information that can identify each individual RX200. Furthermore, in S1302, RX200 can also transmit information other than identification information to TX100.

[0093] Next, in S1303, RX200 transmits a signal to TX100 containing information about the power values ​​it requests, and negotiates with TX100 to determine the GP. In S1303, the Negotiation phase of the WPC standard communication takes place. RX200 transmits an FOD Status data packet to TX100. This packet includes the Reference Quality Factor Value and the Reference Resonance Frequency Value.

[0094] Next, in S1304, the RX200 and TX100 perform the Calibration phase (CAL processing) according to the WPC standard. The processing performed by the RX200 in this phase is as described above. Note that the CAL processing described above is optional.

[0095] Subsequently, in S1305, RX200 receives power until battery 207 is fully charged. The processing performed by RX200 in this phase is as described above. In the Power Transfer phase, RX200 and TX100 perform foreign object detection processing using the Power Loss method. In S1305, RX200 repeatedly sends CE packets at intervals of t_interval, and finally sends an EPT packet to TX100 to terminate processing.

[0096] Here, we will explain the MPP (Magnetic Power Profile) of the Qi standard. MPP is adopted in the "Qi2 (Qi standard v2.0)" standard of the wireless power receiving standard "Qi". In the WPC standard, there are BPP (Baseline Power Profile) which transmits 5 watts or less of power to the RX200, EPP (Extended Power Profile) which transmits 15 watts or less of power, and the aforementioned MPP. Here, a power profile is a set of features that defines the compliance level of a power transmitting device or a power receiving device. MPP has the function of fixing the TX100 and RX200 in predetermined positions with high precision. Several means can be considered to fix the TX100 and RX200 in predetermined positions with high precision. For example, the transmitting antenna (transmitting coil) of the TX100 and the receiving antenna (receiving coil) of the RX200 can be precisely opposed (facing each other) by using the magnets built into the TX100 and RX200, respectively. In other words, in this case, MPP can be described as an extension of BPP, a power profile that uses magnets to align the power transmission and reception equipment. The magnets can be permanent magnets or electromagnets. When transmitting large amounts of power in rapid charging mode, increasing power transmission efficiency and reducing power loss is desirable for the environment. Note that BPP and EPP use the 100kHz band, while MPP uses a frequency of 360kHz.

[0097] The processing sequences for the RX200 and TX100, which support MPP, will be explained using Figure 14.

[0098] When the RX200 is mounted on top of the TX100, the TX100 transmits a Digital Ping (hereinafter referred to as D-Ping) using a frequency of 128kHz (F1400).

[0099] When the RX200 receives a 128kHz D-Ping (F1400), it sends a Signal Strength (SIG) data packet (SIG packet) to the TX100 (F1401). Subsequently, the RX200 sends an ID packet to the TX100 (F1402). The ID packet contains the major and minor versions of the standards supported by the RX200.

[0100] Then, RX200 sends an Extended Identification (XID) packet to TX100 (F1403). RX200 advertises to TX100 that it supports MPP by storing 0xFE in Bank0 (B0), which indicates the MPP Sub Header (MPP-Selector), within the XID packet. Upon receiving this XID packet, TX100, which supports MPP, recognizes that RX200 supports MPP.

[0101] Next, RX200 sends a Configuration data packet (CFG packet) to TX100 (F1404). Since TX100 supports MPP, and RX200 also supports MPP, TX100 sends an MPP pattern (MPP) to RX200 in response to the CFG packet (F1405). In this way, TX100 notifies RX200 that TX100 itself also supports MPP. An MPP pattern is a bit pattern response that is different from ACK and NAK, and is defined in the Qi standard.

[0102] When RX200 receives an MPP pattern, it sends a GRQ(ID) from the General Request Packet to TX100 requesting identification information (Identifier) ​​from the power transmission equipment (F1406). Upon receiving the GRQ(ID), TX100 sends its own ID to RX200 (F1407). Subsequently, RX200 sends a GET / PTx Extended ID to TX100 to request the transmission of Extended Identification (F1408). Upon receiving the GET / PTx Extended ID, TX100 sends its own XID to RX200 (F1409).

[0103] Next, RX200 sends an SRQ / freqsel to TX100 using a Negotiation phase with a frequency of 128kHz (F1410). This causes RX200 to select an operating frequency of 360kHz and request a change in operating frequency. TX100 sends an ACK to SRQ / freqsel (F1411). This confirms that TX100 has accepted the above request for a change in operating frequency.

[0104] TX100 has a function to temporarily stop power transmission and then resume it after a specified delay period (this is EPT / rep, as described later). RX200 sends an SRQ / rep packet containing the above delay period to TX100 (F1412). If TX100 accepts the delay period, it sends an ACK to RX200 (F1413).

[0105] Subsequently, RX200 sends SRQ / en to TX100, requesting the termination of the Negotiation phase using a frequency of 128kHz (F1414). TX100 sends an ACK to SRQ / en, terminating the Negotiation phase (F1415). RX200 then sends End Power Transfer / re-ping (EPT / rep) to TX100 (F1416). EPT / rep is used to have TX100 resume power transfer after a specified delay.

[0106] When TX100 receives an EPT / rep, it removes the power signal (stops transmitting power) and resumes D-Ping transmission after a specified delay. At this point, when TX100 resumes transmission, it transmits D-Ping using the 360kHz frequency selected by RX200 in SRQ / freqsel (F1417).

[0107] When RX200 receives D-Ping, it sends a SIG packet (F1418) and an ID packet (F1419) to TX100. Subsequently, RX200 sends an MPP Extended Identification (MPP-XID) packet to TX100 (F1420). The MPP-XID packet contains various parameters. These parameters include the DC output voltage V rectified by the RX200's rectifier circuit. RECT This includes α, which is a parameter used to estimate the coupling coefficients, as described later. 0rx (Alpha0 Rx), α 0rx (Alpha1 Rx) and α k_threshold (Alpha-Kth Rx) is included.

[0108] Next, RX200 sends a CFG packet to TX100 (F1421) and receives an MPP response from TX100 (F1422). Upon receiving the MPP response, RX200 transitions to the 360kHz Negotiation phase.

[0109] The RX200 sends a GET / PTx Extended ID (GET / PTX XID) packet to the TX100 requesting additional information to identify the TX100 (F1423). The TX100 then sends an Extended Power Transmitter Identification (PTX XID) packet to the RX200 (F1424). This XID packet contains the device identification information of the TX100.

[0110] Subsequently, RX200 transmits an Extended Power Receiver Capabilities (ECAP) packet providing the capabilities information of the power receiving device to TX100 (F1425), and receives an ACK from TX100 as a response (F1426). Then, RX200 transmits a GET / ECAP packet to TX100 to request the capabilities information of TX100 (F1427). TX100 transmits an Extended Power Transmitter Extended Capabilities (ECAP) packet to RX200 (F1428).

[0111] Then, RX200 transmits a GET / PLAP packet to TX100 to request the transmission of Power Loss Accounting Parameters (PLAP) (F1429). TX100 transmits PLAP to RX200 (F1430). The PLAP transmitted by TX100 is the parameter g coil loss,RX for calculating or determining the power loss P of the power receiving coil, which will be described later. coil,RX subsequently, RX200 transmits the PLAP of RX200 to TX100 (F1431). The PLAP of RX200 includes the parameters α FM loss and P coil loss,TX for calculating or determining P FM (Alpha_FM), α FM,DC (Alpha_FM_DC) and g coil,TX (g_coil_TX). RX200 receives an ACK from TX100 as a response to the PLAP (F1432).

[0112] RX200 transmits a GET / EGPL packet, which is an Extended Power Level Selection packet for negotiating the power level of the load power, to TX100 (F1433). TX100 transmits an ACK to RX200 if it can accept the power level stored in the GET / EGPL packet (F1434).

[0113] Then, RX200 sends SRQ / en to TX100 (F1435). This prompts RX200 to request the end of the negotiation phase using the 360kHz frequency. TX100 sends an ACK to RX200 for SRQ / en, ending the negotiation phase (F1436).

[0114] Once the negotiation phase is complete, RX200 periodically sends XCE packets to TX100 (F1437) that provide feedback (the Control Error Value mentioned above) regarding the power level required in MPP. The XCE packets correspond to the CE packets mentioned above. TX100 sends an ACK to RX200 if it accepts the voltage change request indicated by the Control Error Value stored in the XCE packet (F1438). RX200 also periodically sends Power Loss Accounting (PLA) packets to TX100 (F1439) which are used for foreign object detection in MPP. The PLA packets contain Received Power, which is the estimated received power value at RX200, and the power P measured by the rectifier circuit. RECT The data is stored there. TX100 performs foreign object detection based on the PLA packet. If TX100 determines that there is no foreign object and that power transmission is safe, it sends an ACK to RX200 (F1440).

[0115] Here, we will explain MPP Power Loss Accounting (MPLA), which is a foreign object detection function in MPP.

[0116] The TX100 reduces power loss P in foreign matter. FO Calculate P FO P is compared with the threshold. FOIf the value exceeds a threshold, TX100 determines that a foreign object is present or potentially present and limits the transmitted power. Then, RX200 limits the received power. Here, the state in which a foreign object is present (or potentially present) between TX100 and RX200, and the state in which no foreign object is present between TX100 and RX200, are examples of states between the power transmission device and the power receiving device. Furthermore, the various coefficients described later are examples of information used to calculate or determine the state in which a foreign object is present between TX100 and RX200.

[0117] P FO P FO =P PT -P PR It is expressed as P PT This is the total amount of power transmitted by TX100 through the interface surface of TX100. PR This is the total amount of power received (power received by the RX200) through the interface surface of the RX200. The interface surface of the TX100 is the flat part of the TX100's surface closest to the transmitting coil. The interface surface of the RX200 is the flat part of the RX200's surface closest to the receiving coil.

[0118] Next, P PT This explains P PT P PT =V IN I IN -P circuit loss,TX +P coil loss,TX +P FM loss It is expressed as follows.

[0119] The first term V on the right-hand side of the above equation IN I IN Regarding V IN This is the DC input voltage of the TX100 inverter, and I IN This is the DC input current of the TX100 inverter. TX100 is V IN and I INBecause it is possible to measure V IN I IN It is possible to calculate this.

[0120] The second term P on the right-hand side of the above equation. circuit loss,TX This is the power loss in the circuit including the inverter of the TX100. The TX100 is P circuit loss,TX It is possible to measure or calculate this.

[0121] The third term P on the right-hand side of the above equation. coil loss,TX This is the power loss in the transmission coil. coil loss,TX teeth,

number

[0122] b coil R coil air,TX Here, R represents the equivalent mated resistances corresponding to the power transmission coil, which TX100 has stored in memory 106 beforehand. coil air,TX This represents the AC (Alternative Current) resistance of the transmission coil at the switching frequency, and is pre-stored in memory 106 by TX100.

[0123] I TX This is the AC output current of the TX100 inverter (AC input current of the transmission coil or resonant capacitor), which the TX100 can measure or calculate.

[0124] g coil,TX This is the Ecosystem scaling coefficient. TX100 is g coil,TX Using

number

[0125] Here, g coil,TX is

Number

Number

[0126] Here, the "power transmission device of the system model" is the reference power transmission device, and its specifications are disclosed in the Qi standard. Hereinafter, in this specification, the "power transmission device of the system model" is referred to as the reference power transmission device. Also, the "power receiving device of the system model" is the reference power receiving device, and its specifications are disclosed in the Qi standard. Hereinafter, in this specification, the "power receiving device of the system model" is referred to as the reference power receiving device.

[0127]

Number

Number

[0128] The RX200 holds g coil,TX This information is stored in the PLAP packet mentioned above and notified to TX100.

[0129] The fourth term P on the right-hand side of the above equation FM loss This refers to power loss in friendly metal. Friendly metal refers to essential parts (components) of the RX200 or TX100 that may unintentionally generate heat when exposed to power signals (power signals, the power transmitted by the TX100). FM loss teeth,

number

[0130] Friendly metal loss coefficient α FM and α FM,DC This is a characteristic value when the reference power transmission device and the power receiving device to be actually used (i.e., the RX200 itself) are facing each other. FM loss teeth,

number

number

[0131] TX100 uses the ecosystem scaling factor g FM and g FM,DC to correct each term on the right side of [Number] <000963> .

[0132] The coefficient g FM is [Number] expressed as. [Number] Assuming that, the descriptions of {a} and {b} are [Number] the same as the description above, so the description is omitted. [Number] is a scaling factor representing the characteristics when the power transmission device actually being used (i.e., TX100 itself) is opposed to the reference power receiving device. TX100 [Number] pre-holds in memory 106. Furthermore, TX100 holds the characteristic value [Number] in memory 106.

[0133] The TX100 is

number

number

number

number

[0134] Also, the coefficient g FM,DC teeth,

number

number

number

number

[0135] The TX100 is

number

[0136] TX100 calculates or determines g FM,DC and α FM,DC from g FM,DC α FM,DC to calculate or determine g.

[0137] Through the above processing, TX100 calculates or determines P PT to calculate or determine P.

[0138] Next, P PR will be described. P PR is P PR = V RECT I RECT + P circuit [[ID=**44**]] loss,RX + P coil loss,RX and is expressed as follows.

[0139] Regarding the first term V RECT I RECT on the right side of the above equation, V RECT is the DC output voltage rectified in the rectifier circuit of RX200, and I RECT is the DC output current rectified in the rectifier circuit. RX200 can measure V RECT and I RECT .

[0140] Regarding the second term P circuit loss,RX on the right side of the above equation, it is the power loss in the circuit including the rectifier circuit of RX200. RX200 can measure or calculate P circuit loss,RX .

[0141] Regarding the third term P coil loss,RX on the right side of the above equation, it is the power loss in the power receiving coil. P coil loss,RX is Note: There seems to be an extra closing tag loss,RX in the original text at line 44 which might be a mistake. I've translated it as is but it's possible there was an error in the original source.

number

[0142] R coil air,RX This represents the AC resistance of the receiving coil at the switching frequency, and is pre-stored in memory 208 by the RX200.

[0143] Also, P coil loss,RX To accurately calculate this, the RX200 uses the AC current I flowing through the receiving coil. coil,RX It is necessary to measure, but the RX200 is coil,RX It is difficult to calculate accurately. Therefore, P coil loss,RX To calculate this,

number

number

[0144] Ecosystem scaling coefficient g coil,RX teeth,

number

number

number

number

number

[0145] The TX100 is

number

number

[0146] Through the above process, the RX200 is V RECT I RECT , P circuit loss,RX and P coil loss,RX From, P PR The RX200 periodically calculates or determines the P PR This information is stored in the aforementioned PLA packet (F1438) and periodically notified to the TX100.

[0147] Through the above process, TX100 becomes P PT and P PR Calculate or determine P FO Foreign object detection is performed based on the following criteria.

[0148] Next, the configuration of the power transmission device in the Qi standard will be explained using Figure 9(a). Figure 9(a) is a diagram illustrating the power transmission antenna and the power transmission device enclosure. The power transmission device enclosure (casing) contains the power transmission antenna (power transmission coil). In this specification, as shown in Figure 9(a), the distance from the bottom surface of the power transmission antenna (power transmission coil) to the interface surface (top surface, bottom surface) of the power transmission device enclosure is defined as dZ. PTX This is defined as follows. Therefore, dZ PTX This can be described as the distance between the power transmission antenna (power transmission coil) and the power transmission device enclosure.

[0149] Figure 9(b) shows the configuration of a power receiving device in the Qi standard and illustrates the power receiving antenna and power receiving device enclosure. The power receiving device enclosure (casing) contains the power receiving antenna (power receiving coil). In this specification, as shown in Figure 9(b), the distance from the bottom surface of the power receiving antenna (power receiving coil) to the interface surface (top surface, bottom surface) of the power receiving device enclosure is defined as dZ. PRX This is defined as follows. Therefore, dZ PRX This can be described as the distance between the receiving antenna (receiving coil) and the receiving device enclosure.

[0150] Furthermore, in the Qi standard, the dZ of MPP power receiving devices and reference power receiving devices PRX Regarding this, the nominal value is 0.66 mm. In other words, the dZ of the reference power receiving device and the power receiving device (RX200) PRX If the nominal value is equivalent to 0.66 mm, then the explained g FM , g FM,DC and g coil,RX Using P FMloss and P coil loss,RX It can be calculated with high accuracy. However, the dZ of the power receiving device (RX200) PRX However, if it differs from the nominal value of 0.66 mm by more than a certain amount (for example, 1.5 mm or 2.0 mm), P FM loss and P coil loss,RX The calculation accuracy decreases, making it difficult to accurately detect foreign objects.

[0151] Therefore, in this embodiment, the dZ of the power receiving device (RX200) PRX This technology provides accurate detection of foreign objects when their size differs from the nominal value of 0.66 mm by a certain amount or more.

[0152] Figure 10 is a conceptual diagram of the information held in the memory 106 of TX100 according to this embodiment. More specifically, Figure 10 shows an example of the ecosystem scaling coefficient that TX100 has pre-stored in the memory 106. Figure 10(a) shows P FM loss and P coil loss,RX This shows the ecosystem scaling coefficients related to the calculation of [the relevant value].

[0153] Memory 106 contains dZ PRX The nominal value of 1000 is maintained. 0.66mm is the nominal value of the current Qi standard. Also, 1.5mm is the dZ of the RX200. PRX This is the nominal value.

[0154] Memory 106 also contains g FM 1001, g FM,DC 1002 and g coil,RX 1003 is also retained. According to Figure 10(a), dZ PRX If it is 0.66 mm, g FM is A, and g FM,DC is B, and g coil,RX It is C. Also, dZ PRX If it is 1.5 mm, g FM is D, and g FM,DC is E, and gcoil,RX It is F. Thus, the TX100 has multiple dZ PRX Each instance maintains multiple corresponding ecosystem scaling factors.

[0155] The information shown in Figure 10(a) is an example of correspondence information (which may also be called correspondence information in which distance information and parameters are associated) that links distance information with information for calculating or determining the state between the power transmission device and the power receiving device.

[0156] Figure 11 shows an example of the format of an ID packet transmitted by the RX200 according to this embodiment. More specifically, Figure 11 shows an example of a Report [PRX Identification] packet transmitted by the RX200 in MPP. As shown in Figure 11, the three bits from bit 2 (b2) to bit 4 (b4) of Bank0 (B0) are dZ PRX This indicates this dZ PRX The 3 bits indicating this represent the RX200's dZ PRX Information indicating nominal values ​​related to this will be stored. Specifically, the dZ of the current MPP standard. PRX The information indicating the nominal value of 0.66mm is set to "000", and the RX200's dZ PRX For example, the information indicating the nominal value of 1.5 mm is set to "001". In this case, 3 bits are used to create up to 8 different dZ values. PRX It is possible to store the nominal value of dZ. This information is dZ PRX This may also be information indicating whether the value is below a predetermined threshold or within a predetermined range. For example, dZ PRX If the value is 0.66 mm or more and less than 1.0 mm, the information will be set to "000" and dZ PRX If the value is between 1.0 mm and 1.5 mm, the information may be set to "001". Also, dZ PRX If it is less than 1.5 mm, the information will be set to "000" and dZ PRX If the value is 1.5 mm or more, the information may be set to "001". In this case, it is possible to store up to 8 different ranges using 3 bits.

[0157] The method of storing the information is not limited to the above. For example, the information may be stored in an MPP-Extended Identification Packet (Qi MPP Extended Identification, MPP-XID data packet). Alternatively, the information may be stored in a newly defined packet.

[0158] Figure 12 is a flowchart showing an example of processing in a power transmission device according to an embodiment. Figure 12(a) is a flowchart showing the MPLA-related processing in the TX100 according to the first embodiment.

[0159] TX100, for example, upon receiving the aforementioned Report[PRX Identification] packet, will enter the dZ PRX Information regarding the RX200 is received from the TX100 (F1200). Then, the TX100 obtains foreign object detection parameters corresponding to the information obtained (received) by the F1200 (F1201). Specifically, the TX100 obtains the dZ information from the RX200 in F1200. PRX Let's assume that information indicating a nominal value of 1.5 mm has been received. Then, in F1201, TX100 will, based on the information held in memory 106 shown in Figure 10(a), g FM is D, and g FM,DC is E, and g coil,RX The information obtained is that it is F. Then, TX100 uses the obtained parameters to P FO The value is calculated and foreign object detection is performed (F1202).

[0160] The following explanation will use the sequence diagram shown in Figure 14 to describe the example explained with reference to Figure 12(a).

[0161] The RX200 uses an ID packet (F1419) to determine its own dZ PRX The information that it is 1.5 mm is notified to TX100. Based on the notified information, TX100 uses the information held in memory 106 shown in Figure 10(a) to determine g coil,RXThe TX100 sends a PLAP packet containing the value F to the RX200 (F1430). The TX100 then receives the PLA packet from the RX200 (F1439). Upon receiving this PLA packet, the TX100 uses the information stored in memory 106 shown in Figure 10(a) to determine the dZ of the RX200. PRX g corresponding to FM D and g are FM,DC Using E, P FO Calculate (F1202). Here, V IN , I IN and I TX TX100 can measure or calculate α. FM , α FM,DC and g coil,RX This is acquired when TX100 receives PLAP from RX200. TX100 is V IN , I IN and I TX And, α FM , α FM,DC and g coil,RX And, g obtained in F1201 FM and g FM,DC Based on that, P FO The system calculates the value and performs foreign object detection.

[0162] Thus, the TX100 is the RX200's dZ PRX Using foreign object detection parameters corresponding to the nominal value of P FO By calculating this, foreign object detection can be performed with high accuracy.

[0163] Note that ID packets are sent by RX200 to TX100 regardless of whether RX200 is receiving 128kHz D-Ping or 360kHz D-Ping (e.g., F1402 and F1419). However, RX200 only includes its own DZ in the ID packet when it is receiving (or has received) 360kHz D-Ping. PRX It stores its own dZ when it receives (or is receiving) a 128kHz D-Ping. PRX Do not store it.

[0164] Furthermore, the RX200 uses its own dZ in the XID packet. PRX When storing the XID packet, the XID packet is sent to the TX100 by the RX200. This transmission of the XID packet occurs regardless of whether the RX200 is receiving a 128kHz D-Ping or a 360kHz D-Ping (e.g., F1403 and F1420). However, the RX200 only stores its own dZ in the XID packet when it is receiving (or has received) a 360kHz D-Ping. PRX It stores its own dZ when it receives (or is receiving) a 128kHz D-Ping. PRX It does not store dZ. PRX This is because all related processes are used in MPP-related functions (MPLA or coupling coefficient estimation, which will be described later).

[0165] Also, in Figure 10(a), dZ PRX g FM , g FM,DC and g coil,RX An example was shown in which g is retained, FM , g FM,DC and g coil,RX Parameters for calculating or determining each of these may be stored in memory 106.

[0166] Figure 10(b) shows g, which is held in memory 106. FM , g FM,DC and g coil,RX This shows an example of parameters for calculating or determining each of these. Note that the information shown in Figure 10(b) is an example of correspondence information, which associates distance information with information for calculating or determining the state between the power transmission device and the power receiving device.

[0167] As shown in Figure 10(b), dZ PRX Each, g FM Constitutes

number

number

number

number

[0168] Also, as shown in Figure 10(b), dZ PRX Each, g FM,DC Constitutes

number

number

[0169] Also, as shown in Figure 10(b), dZ PRX Each, g coil,RX Constitutes

number

number

[0170] The same effect can be obtained with the configuration shown in Figure 10(b).

[0171] [Second Embodiment] In the first embodiment, TX100 is the dZ of RX200 PRXA configuration for obtaining parameters for foreign object detection and performing foreign object detection based on dZ was described. In this embodiment, TX100 is dZ PRX A method for calculating the coupling state index based on the above will be described. Note that the configurations, operations, and processes in the second embodiment described below are the same as or similar to those in the first embodiment, and therefore the description of those configurations, operations, and processes will be omitted.

[0172] First, we will explain the method for measuring the coupling state index between the transmitting and receiving antennas in the Qi standard MPP. Here, the coupling state between TX100 and RX200 is an example of the state between the transmitting and receiving equipment. Furthermore, the various coefficients described later are examples of information used to calculate or determine the coupling state between TX100 and RX200.

[0173] TX100 represents the coupling state (inductive coupling factor) between TX100 and RX200. est k is calculated (estimated or calculated) using the following formula: est This represents the coupling state (inductive coupling coefficient) between the transmitting coil of TX100 and the receiving coil of RX200. k est =E 0xg α 0rx p+E 1xg α 1rx Here, α 0rx =E 0gy / E 0gg And α 1rx =E 1gy / E 1gg And,

number

[0174] The above eigencoefficient is E 0xg , E 1xg , E 0gy , E 0gg , E 1gy and E 1gg These each mean the following:

[0175] Let E{a}{b}{c}, a is {0 or 1}, 0: The slope of linear curve fit. 1: The intercept of a linear curve fit. It means...

[0176] Furthermore, b is a description of the power transmission equipment. g: Power transmission equipment in system model x: General power transmission equipment It means...

[0177] Furthermore, c is a description of the power receiving device. g: Power receiving device of the system model y: General power receiving device It means...

[0178] In other words, E 0gg and E 1gg This is a scaling factor that represents the characteristics when the reference power transmission device and the reference power reception device are placed opposite each other. These scaling factors are calculated in advance by measurement, and their values ​​are stored in memory 208 by the RX200.

[0179] Also, E 0xg and E 1xg This is a scaling factor that represents the characteristics when the reference power receiving device and the power transmitting device (TX100) to be actually used are placed opposite each other. These scaling factors are calculated in advance by measurement, and their values ​​are stored in memory 106 by TX100.

[0180] Also, E 0gy and E 1gyThis is a scaling factor that represents the characteristics when the reference power transmission device and the power receiving device (RX200) to be actually used are paired. These scaling factors are calculated in advance by measurement, and their values ​​are stored in memory 208 by the RX200.

[0181] Also, V rect This is the output voltage after rectification in the RX200's rectifier circuit when the RX200 receives a Digital Ping. The RX200 is V rect After measuring, information regarding the measured value (information indicating the measured value) is transmitted to TX100.

[0182]

number

[0183] Also, V in This is the DC voltage input to the inverter of the TX100, as measured by the TX100, or the voltage output by the inverter of the TX100, as measured by the TX100.

[0184] α 0rx The RX200 holds E in memory 208 0gy and E 0gg From there, calculated or determined by RX200, α 1rx The RX200 holds E in memory 208 1gy and E 1gg It is calculated or determined by the RX200. The RX200 is α 0rx and α 1rx The values ​​are stored in memory 208, and information about these values ​​(information indicating these values) is sent to TX100. α 0rx and α 1rx This is the ecosystem scaling factor.

[0185] E 0xg and E 1xgThis is pre-stored in memory 106 by TX100.

[0186] The TX100 receives V from the RX200. rect Information regarding α 0rx Information regarding and α 1rx Information regarding the TX100 measurements

number

[0187] As described above, the TX100 is the same as the V measured by the RX200. rect The TX100 measured the following:

number

[0188] In the current Qi standard MPP, the RX200's dZ PRX This is based on the premise that it is equivalent to 0.66 mm, and the scaling factor and k mentioned above. est The calculation method for the RX200's dZ is also designed under that premise. Therefore, the RX200's dZ PRX If the distance differs from 0.66 mm by a certain amount or more, the premise is broken, so k est This could potentially make it impossible to calculate accurately.

[0189] Therefore, below, the RX200 dZ PRX When the distance differs from 0.66 mm by a certain amount or more, k est A method for accurately calculating this will be explained using Figures 10 and 12.

[0190] Figure 10(e) shows an example of eigencoefficients related to coupling coefficient estimation that are stored in memory 106. As shown in Figure 10(e), memory 106 contains E 0xg 1004 and E 1xg 1005 is retained. According to Figure 10(e), dZ PRX If it is 0.66 mm, E 0xg G is E 1xg is H. Also, dZ PRX If it is 1.5 mm, E 0xg is I, and E 1xg This is J. Note that the information shown in Figure 10(e) is an example of correspondence information, which associates distance information with information for calculating or determining the state between the power transmission device and the power receiving device.

[0191] Figure 12(b) is a flowchart showing the process related to coupling coefficient estimation in the TX100 process according to the second embodiment.

[0192] TX100, for example, upon receiving the aforementioned Report[PRX Identification] packet, will enter the dZ PRX Information is received (F1200). Then, TX100 obtains parameters for coupling coefficient estimation (coupling coefficient estimation parameters) corresponding to the information obtained (received) in F1200 (F1203). Specifically, in F1200, TX100 obtains the dZ of RX200. PRX Let's assume that information indicating a nominal value of 1.5 mm has been received. Then, in F1203, based on the information held in memory 106 shown in Figure 10(e), E 0xg is I, and E 1xg The information obtained is that it is J. Then, TX100 uses the obtained parameter k est Calculate (F1204).

[0193] The following explanation uses the sequence diagram in Figure 14 to describe the example described in Figure 12(b).

[0194] When TX100 receives an ID packet from RX200 (F1419), it uses the information stored in memory 106 shown in Figure 10(e) to determine E 0xg We obtain the value I as E 1xg The value J is obtained as (F1203). Then, TX100 calculates k based on the coupling coefficient estimation method already described. est The V is calculated (F1204). Specifically, the TX100 obtains the V by receiving the MPP-XID (F1420). rect , α 0rx , α 1rx and α k_threshold And, E obtained in F1203 0xg and E 1xg And, measurable

number

[0195] Thus, the TX100 is the RX200's dZ PRX Using foreign object detection parameters corresponding to the nominal value of k est By calculating this, the coupling coefficients can be estimated with high accuracy.

[0196] [Example 1] In the first embodiment, the dZ of the RX200 PRX If the value differs from the nominal value by a certain amount or more, the TX100 will be the RX200's dZ PRX Based on this, a configuration for obtaining parameters for foreign object detection and performing foreign object detection was described. In this modified example, dZ PRX not only dZ PTX This section will explain cases where the value differs from the nominal value by a certain amount or more.

[0197] In the Qi standard, the dZ of MPP power transmission equipment and reference power transmission equipment PTX The nominal value is 1.2 mm. In other words, the reference power transmission device and the dZ of the power transmission device PTX When the nominal value is equivalent to 1.2 mm, the g already explainedcoil,TX Using P coil loss,TX This can be calculated with high accuracy. Similarly, the dZ of the reference power transmission device and the power transmission device PTX When the nominal value is equivalent to 1.2 mm, α FM and α FM,DC Using P FM loss It can be calculated with high accuracy. However, the dZ of the power transmission device (TX100) PTX If it differs from the nominal value of 1.2 mm by more than a certain value, P coil loss,TX and P FM loss Because the calculation accuracy is low, foreign object detection cannot be performed accurately.

[0198] Therefore, this modified example describes a method for accurately detecting foreign objects even in such cases.

[0199] The TX100 has parameters for foreign object detection and the distance dZ between the transmitting and receiving coils. PTX +dZ PRX It stores multiple pieces of information that associate with each other. To simplify the explanation, the TX100's dZ PTX The nominal value is said to be 2.0mm, unlike the current standard of 1.2mm. The TX100 is dZ PTX The information that it is 2.0mm is stored in memory 106.

[0200] Furthermore, the TX100 also holds the following information (examples of correspondence information, where distance information and information for calculating or determining the state between the power transmission device and the power receiving device are associated with each other). ·dZ PTX +dZ PRX g in the case of =3.5mm FM , g FM,DC and g coil,RX (dZ PRX (This corresponds to 1.5 mm). ·dZ PTX +dZ PRX g in the case of =4.0mm FM , g FM,DC and g coil,RX(dZ PRX (This corresponds to 2.0 mm).

[0201] Here, TX100 receives dZ from RX200. PRX Based on the information, dZ PTX +dZ PRX Calculate or determine the dZ PTX +dZ PRX g corresponding to FM , g FM,DC and g coil,RX Select this option.

[0202] Similar effects can be achieved even with this configuration.

[0203] Furthermore, the configuration relating to this modified example may also be applied to the second embodiment. In that case, TX100 has multiple dZ PTX +dZ PRX Each, E 0xg and E 1xg It is sufficient to retain this. This also allows for accurate estimation of the coupling coefficients.

[0204] [Differentiation 2] In the first embodiment, the dZ of the RX200 PRX An example of correcting the coefficients based on [the given formula] was explained. This modified example describes other examples.

[0205] Specifically, g FM Regarding

number

number

number

number

number

number

[0206] Figure 10(c) shows

number

number

number

[0207] According to Figure 10(c), the RX200's dZ PRX (1.5mm)

number

number

number

number

number

number

[0208] Even in this way, one of the coefficients is corrected, so the current dZ for RX200 PRX This method enables more accurate foreign object detection compared to using the (0.66mm) coefficient directly.

[0209] Also, Figure 10(d) shows

number

number

number

[0210] According to Figure 10(d), the RX200's dZ PRX (1.5mm)

number

number

number

number

number

number

[0211] Even in this way, one of the coefficients is corrected, so the current dZ for RX200 PRX This method enables more accurate foreign object detection compared to using the (0.66mm) coefficient directly.

[0212] Furthermore, the configuration of this modified example may also be applied to Modified Example 1. In that case, TX100 has multiple dZ PTX +dZ PRX It maintains multiple ecosystem scaling factors corresponding to each.

[0213] [Difference 3] In the first embodiment, TX100 is a multiple dZ of RX200 PRX Each, g FM , g FM,DC and g coil,RX A configuration in which this is stored in memory 106 was described.

[0214] In this modified example, the weighting coefficient for the reference value is dZ PRX The configuration to be maintained for each will be explained.

[0215] Here, the reference value is dZ PRX When g is the nominal value of the current standard, which is 0.6 mm FM and g FM,DC We define this as follows, and define the corresponding weighting coefficients as X and Y.

[0216] Then, P FM loss teeth,

number

[0217] Referring to Figure 10(a), g FMis A, g FM,DC is B. Here, dZ PRX When the value is 1.5 mm, X becomes D / A and Y becomes E / B.

[0218] Also, P coil loss,RX Regarding this, if we define the weighting coefficient as Z,

number

[0219] Now, referring to Figure 10(a), g coil,RX is C, and Z is F / C.

[0220] Similar effects can be achieved even with the configuration described above.

[0221] Furthermore, it is clear that the configuration of this modified example may also be applied to Modified Example 1.

[0222] Furthermore, the configuration of this modified example may also be applied to Modified Example 2. PRX Each,

number

number

number

number

number

number

[0223] P coil loss,RX Regarding

number

number

[0224] Similarly, referring to Figure 10(d),

number

number

number

[0225] P coil loss,RX Regarding

number

number

[0226] The configuration of this modified example may also be applied to Modified Example 2. In this case, the same effect can be obtained.

[0227] Furthermore, the configuration of this modified example may also be applied to the second embodiment. If the weighting coefficients are V and W, k est =VE 0xg α 0rx p+WE 1xg α 1rx This can be written as follows. Now, referring to Figure 10(e), E 0xg It becomes G, and E 1xg This becomes H. And dZ PRX When the ratio is 1.5 mm, V becomes I / G and W becomes J / H.

[0228] [Other variations] In the first embodiment, the second embodiment, modification 1, modification 2, and modification 3, TX100 is dZ PRX It was explained that it holds coefficients corresponding to each of two values. However, TX100 may hold coefficients corresponding to three or more values, rather than just two.

[0229] Furthermore, the TX100 has multiple dZ PRX We have described how to maintain the corresponding coefficients and how to select the appropriate coefficient from the maintained coefficients, but the appropriate coefficient may be selected, calculated, or determined by other means. For example, dZ PRX =0.66mm and dZ PRX When = 1.5 mm, the coefficient g described in the first embodiment, second embodiment, modified example 1, modified example 2, and modified example 3 applies to each case. FM , g FM,DC , g coil,RX ,

number

number

number

number

number

number

[0230] Furthermore, Figure 13 shows a flowchart illustrating an example of operation when the power receiving device according to the first embodiment is mounted on a power transmission device that complies with the current (or earlier) Qi standard, which does not correspond to the operation flow shown in Figure 12.

[0231] The RX200 uses PLAP packets with dZ PRX Information regarding the corresponding alpha FM , α FM,DC and g coil,TX It stores and sends a PLAP packet (F1300). Here, RX200 is dZ PRX Information regarding this is stored in the reserved area of ​​the current PLAP packet. For example, the RX200 stores information in the dZ PRX The value "001", indicating that it is 1.5 mm, is stored in the reserved area.

[0232] Here, power transmission equipment that does not conform to the operation flow shown in Figure 12 and is based on the current standard is dZ PRX The information regarding the packet cannot be understood. Therefore, the power transmission device does not send an ACK to the PLAP packet, but responds with NAK (Not Defined) to indicate rejection or ND (Not Defined) to indicate that the packet cannot be understood. Therefore, NAK and ND are dZ PRX This can be described as a negative response to information regarding that topic.

[0233] If the RX200 does not receive an ACK and instead receives a NAK or ND (NO in S1301), it limits the power received (F1302). Also, if the RX200 receives an ACK (YES in F1302), it terminates processing.

[0234] Here, "limiting the received power" can mean sending an EPT (Electronic Power Transfer) instructing a power cutoff, or limiting the received power to a specific power value (e.g., 5 watts). Methods for limiting to a specific power value include BPP (Broadband Power Packing), where the maximum received power is 5 watts, or MPP-Restricted mode, which is a type of MPP but uses the BPP protocol to perform one-way communication at an operating frequency of 360 kHz. Here, the one-way communication mentioned above is communication from the power receiving device to the power transmitting device. It is also possible to operate in MPP Full mode, which allows for more complex operations than Restricted mode, but with a configuration where the received power (the power requested by the SRQ / EGPL mentioned above) is limited to a maximum of 5 watts. In MPP Full mode, a maximum received power of 15 watts, bidirectional communication, power negotiation exchange and authentication are possible, but in this configuration, the received power is limited to a maximum of 5 watts. Furthermore, the RX200 may autonomously decide which one or more of the above-mentioned methods for "limiting the received power" to use, or the TX100 may notify or instruct the RX200 to use.

[0235] Thus, if the power transmission equipment is an older (or current) standard power transmission equipment that does not support the operation flow shown in Figure 12, the RX200 can reduce the risk of foreign object overheating or ignition by limiting the received power, which can prevent accurate foreign object detection.

[0236] [Other embodiments] Some (or all) of the configurations in the above embodiments may be replaced with other configurations that perform similar functions, or omitted, and other configurations may be added. Furthermore, it is not limited to the WPC standard and can be applied to various standards.

[0237] Furthermore, for example, the receiving device may possess some or all of the functions of the power transmission device (see, for example, Figure 6). Alternatively, the receiving device may perform some or all of the processes that the power transmission device should perform (see, for example, Figures 7 and 12).

[0238] Furthermore, the configurations in the above-described embodiments may be combined as appropriate.

[0239] Furthermore, the power transmission and receiving devices may be, for example, image input devices such as imaging devices (still cameras, video cameras, etc.) or scanners, or image output devices such as printers, copiers, or projectors. In addition, the power transmission and receiving devices may be storage devices such as hard disk drives or memory devices, or information processing devices such as personal computers (PCs), smartphones, or tablet devices.

[0240] Furthermore, the power receiving device in this disclosure may also be an information terminal device. For example, an information terminal device has a display unit that displays information to the user and is supplied with power received from a power receiving antenna. The power received from the power receiving antenna is stored in a power storage unit (battery), and power is supplied to the display unit from the battery. In this case, the power receiving device may also have a communication unit that communicates with other devices different from the power transmitting device. The communication unit may support communication standards such as NFC communication or fifth-generation mobile communication systems (5G).

[0241] Furthermore, the power receiving device in this disclosure may be a vehicle such as an automobile. For example, an automobile that is a power receiving device may receive power from a charger (power transmission device) via a power transmission antenna installed in a parking lot. Alternatively, an automobile that is a power receiving device may receive power from a charger (power transmission device) via a power transmission antenna embedded in the road. Such an automobile supplies the received power to a battery. The power from the battery may be supplied to a drive unit (motor, electric unit) that drives the wheels, or it may be used to drive sensors used for driving assistance or a communication unit that communicates with external devices. In other words, in this case, the power receiving device may have a battery, motors and sensors that are driven using the received power, and a communication unit that communicates with devices other than the power transmission device, in addition to the wheels. Furthermore, the power receiving device may have a compartment for accommodating people. For example, sensors may be used to measure the distance between vehicles or the distance to other obstacles. The communication unit may be compatible with, for example, the Global Positioning System (Global Positioning Satellite, GPS). Furthermore, the communication unit may support communication standards such as the fifth-generation mobile communication system (5G). Also, the vehicle may be a bicycle or a motorcycle.

[0242] Furthermore, the power receiving device in this disclosure may be a power tool, a home appliance, or the like. These power receiving devices may have a battery, as well as a motor driven by the power received from the battery. These devices may also have a notification means for notifying the remaining battery level, etc. These devices may also have a communication unit that communicates with other devices different from the power transmitting device. The communication unit may support communication standards such as NFC or fifth-generation mobile communication systems (5G).

[0243] Furthermore, the power transmission device in this disclosure may also be an in-vehicle charger that transmits power to portable information terminal devices such as smartphones and tablets that support wireless power transmission within a vehicle. Such an in-vehicle charger may be installed anywhere in the vehicle. For example, the in-vehicle charger may be installed on the vehicle's console, on the instrument panel (dashboard), between passenger seats, on the ceiling, or on the door. However, it is preferable not to install it in a location that would interfere with driving. In addition, although the power transmission device has been described using the example of an in-vehicle charger, such chargers are not limited to those installed in vehicles, but may also be installed in transport vehicles such as trains, airplanes, and ships. In this case, the charger may also be installed between passenger seats, on the ceiling, or on the door.

[0244] Alternatively, a vehicle such as an automobile equipped with an on-board charger may also serve as a power transmission device. In this case, the power transmission device has wheels and a battery, and uses the power from the battery to supply power to the power receiving device via a power transmission circuit and a power transmission antenna.

[0245] This disclosure can also be implemented by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be implemented by a circuit (e.g., an ASIC) that implements one or more functions.

[0246] Furthermore, some of the processes described in this disclosure with reference to the flowchart may be implemented in hardware. For example, a dedicated circuit can be automatically generated on the FPGA from a program to implement each step by using a predetermined compiler. Alternatively, a Gate Array circuit may be formed in the same way as the FPGA and implemented in hardware.

[0247] Furthermore, the following additional information is disclosed regarding the above embodiments.

[0248] [Note 1] A power transmission device that wirelessly transmits power to a power receiving device, A receiving means that receives first information from the power receiving device regarding the distance between a power receiving coil in the power receiving device and an enclosure in the power receiving device that encloses the power receiving coil, Processing means that perform specific processing based on the first information, A power transmission device characterized by having the following features.

[0249] [Note 2] The power transmission device according to Appendix 1, characterized in that the aforementioned specific process is a process for detecting foreign matter.

[0250] [Note 3] The power transmission device according to Appendix 1, characterized in that the aforementioned specific process is a process that determines the coupling state between the power transmission device and the power receiving device.

[0251] [Note 4] The power transmission device according to any one of the appendices 1 to 3, characterized in that the processing means determines a parameter corresponding to the first information from a plurality of parameters and performs the specific processing based on the determined parameter.

[0252] [Note 5] The power transmission device according to Appendix 4, characterized in that the processing means determines a parameter corresponding to the first information from the plurality of parameters based on correspondence information in which distance information and parameters are associated.

[0253] [Note 6] The power transmission device according to Appendix 5, characterized in that the distance information indicates the distance between the power receiving coil and the enclosure enclosing the power receiving coil.

[0254] [Note 7] Transmission coil and The enclosure containing the aforementioned power transmission coil, It further possesses, The aforementioned distance information represents the sum of the distance between the transmitting coil and the enclosure enclosing the transmitting coil, and the distance between the receiving coil and the enclosure enclosing the receiving coil. The power transmission device according to Appendix 5, characterized in that the processing means determines the distance between the power transmission coil and the enclosure, and parameters corresponding to the first information, based on the corresponding information.

[0255] [Note 8] The aforementioned first information is included in the aforementioned corresponding information, The power transmission device according to any one of appendices 5 to 7, characterized in that the processing means determines the parameter associated with the first information in the corresponding information.

[0256] [Note 9] The aforementioned first information is not included in the aforementioned corresponding information. The power transmission device according to any one of Appendix 5 to 7, characterized in that the processing means determines parameters corresponding to the first information based on a graph or calculation formula determined from the corresponding information.

[0257] [Note 10] A power receiving device that receives power wirelessly from a power transmission device, The power receiving coil and The enclosure containing the aforementioned power receiving coil, A transmitting means for transmitting information regarding the distance between the power receiving coil and the enclosure to the power transmission device, A power receiving device characterized by having the following features.

[0258] [Note 11] A receiving means for receiving a negative response to the aforementioned information from the power transmission device, In response to the aforementioned negative response, a limiting means for limiting the received power, The power receiving device according to Appendix 10, further characterized by having the following:

[0259] [Note 12] A method used by a power transmission device to wirelessly transmit power to a power receiving device, A step of receiving first information from the power receiving device regarding the distance between a power receiving coil in the power receiving device and an enclosure in the power receiving device that encloses the power receiving coil, A step of performing a specific process based on the first information mentioned above, A method characterized by having the following:

[0260] [Note 13] A method used by a power receiving device that receives power wirelessly from a power transmission device, A process of transmitting to the power transmission device information regarding the distance between a power receiving coil in the power receiving device and an enclosure in the power receiving device that encloses the power receiving coil. A method characterized by having the following:

[0261] [Note 14] A program that causes a computer to perform the actions described in Appendix 12 or 13. [Explanation of symbols]

[0262] 100: Power transmission equipment 101, 201: Control Unit 103: Power Transmission Section 105: Power transmission antenna 200: Power receiving device 203: Power receiving section 205: Receiving antenna 303:Measurement part 304: Settings Section 305: State detection unit

Claims

1. A power transmission device that wirelessly transmits power to a power receiving device, A receiving means that receives first information from the power receiving device regarding the distance between a power receiving coil in the power receiving device and an enclosure in the power receiving device that encloses the power receiving coil, Processing means that perform specific processing based on the first information, A power transmission device characterized by having the following features.

2. The power transmission device according to claim 1, characterized in that the aforementioned specific process is a process for detecting foreign matter.

3. The power transmission device according to claim 1, characterized in that the aforementioned specific process is a process that determines the coupling state between the power transmission device and the power receiving device.

4. The power transmission device according to claim 1, characterized in that the processing means determines a parameter corresponding to the first information from a plurality of parameters and performs the specific processing based on the determined parameter.

5. The power transmission device according to claim 4, characterized in that the processing means determines a parameter corresponding to the first information from the plurality of parameters based on correspondence information in which distance information and parameters are associated.

6. The power transmission device according to claim 5, characterized in that the distance information indicates the distance between the power receiving coil and the enclosure enclosing the power receiving coil.

7. Transmission coil and The enclosure containing the aforementioned power transmission coil, It further possesses, The aforementioned distance information represents the sum of the distance between the transmitting coil and the enclosure enclosing the transmitting coil, and the distance between the receiving coil and the enclosure enclosing the receiving coil. The power transmission device according to claim 5, characterized in that the processing means determines the distance between the power transmission coil and the enclosure, and parameters corresponding to the first information, based on the corresponding information.

8. The aforementioned first information is included in the aforementioned corresponding information, The power transmission device according to claim 5, characterized in that the processing means determines the parameters associated with the first information in the corresponding information.

9. The aforementioned first information is not included in the aforementioned corresponding information. The power transmission device according to claim 5, characterized in that the processing means determines parameters corresponding to the first information based on a graph or calculation formula determined from the corresponding information.

10. A power receiving device that receives power wirelessly from a power transmission device, The power receiving coil and The enclosure containing the aforementioned power receiving coil, A transmitting means for transmitting information regarding the distance between the power receiving coil and the enclosure to the power transmission device, A power receiving device characterized by having the following features.

11. A receiving means for receiving a negative response to the aforementioned information from the power transmission device, In response to the aforementioned negative response, a limiting means for limiting the received power, The power receiving device according to claim 10, further comprising the above.

12. A method used by a power transmission device to wirelessly transmit power to a power receiving device, A step of receiving first information from the power receiving device regarding the distance between a power receiving coil in the power receiving device and an enclosure in the power receiving device that encloses the power receiving coil, A step of performing a specific process based on the first information mentioned above, A method characterized by having the following:

13. A method used by a power receiving device that receives power wirelessly from a power transmission device, A process of transmitting to the power transmission device information regarding the distance between a power receiving coil in the power receiving device and an enclosure in the power receiving device that encloses the power receiving coil. A method characterized by having the following:

14. A program for causing a computer to perform the method described in claim 12 or 13.

Images