Power reception device, power transmission device, method performed by power reception device, method performed by power transmission device, and program

Abstract

A power reception device according to one aspect of the present disclosure wirelessly receives power from a power transmission device, is used for foreign object detection, and transmits individual parameters for each of a plurality of states to the power transmission device.

Description

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

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

[0002] Japanese Patent Publication No. 2012-244732 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.

[0003] Regarding the correction values ​​for detecting foreign objects near power transmission and / or power receiving equipment, these values ​​change depending on the environment (the circumstances or conditions in which the power transmission and / or power receiving equipment are located), such as the temperature of the power transmission and / or power receiving equipment. In such cases, if an appropriate correction value is not selected and used according to the environment, foreign object detection may not be performed properly, and wireless power transmission may not be performed properly.

[0004] Japanese Patent Publication No. 2012-244732

[0005] Regarding the correction values ​​for detecting foreign objects near the device and power receiving equipment, these values ​​change depending on the environment (the circumstances or state in which the power transmitting and / or power receiving equipment is located), such as the temperature of the power transmitting and / or power receiving equipment. In such cases, if an appropriate correction value is not selected and used according to the environment, foreign object detection may not be performed properly, and wireless power transmission may not be performed properly.

[0006] One aspect of this disclosure provides, in view of the above, a technology for appropriately performing wireless power transmission.

[0007] A power receiving device according to one aspect of the present disclosure is characterized by comprising: a power receiving means for wirelessly receiving power from a power transmitting device; and a communication means used for detecting foreign objects and transmitting individual parameters for each of a plurality of states to the power transmitting device.

[0008] A power receiving device according to one aspect of the present disclosure is characterized by comprising: a power receiving means for wirelessly receiving power from a power transmitting device; and a communication means used for detecting foreign objects and transmitting individual parameters for each of a plurality of states to the power transmitting device.

[0009] This is a diagram showing an example configuration of a wireless charging system according to the first embodiment. This is a functional block diagram showing an example configuration of a power transmission device according to the first embodiment. This is a functional block diagram showing an example configuration of a power receiving device according to the first embodiment. This is a flowchart showing an example of wireless power transmission processing based on the Qi standard by the power receiving device according to the first embodiment. This is a flowchart showing details of a processing example in the Negotiation phase by the power receiving device according to the first embodiment. This is a sequence diagram showing an example of the overall processing of a wireless charging system according to the first embodiment. This is a diagram showing an example of a PLAP packet transmitted by the power receiving device according to the first embodiment to the power transmission device This is a diagram showing an example of a PLAP packet transmitted by a power receiving device according to the first embodiment to a power transmitting device. This is a diagram showing an example of a PLAP packet transmitted by a power receiving device according to the first embodiment to a power transmitting device. This is a diagram showing an example of a PLAP packet transmitted by a power receiving device according to the first embodiment to a power transmitting device. This is a diagram showing an example of a PLAP packet transmitted by a power receiving device according to the first embodiment to a power transmitting device. This is a diagram showing an example of a PLAP packet transmitted by a power receiving device according to the second embodiment to a power transmitting device. This is a diagram showing an example of a PLAP packet transmitted by a power receiving device according to the second embodiment to a power transmitting device. This is a flowchart showing details of a processing example in the Negotiation phase and Power Transfer phase by a power receiving device according to the third embodiment. This is a sequence diagram showing an overall processing example of a wireless charging system according to the third embodiment.This is a diagram illustrating the enclosure of the power transmission device according to the third embodiment. This is a diagram illustrating the enclosure of the power receiving device according to the third embodiment. This is a diagram showing an example of a PLAP packet transmitted by a power receiving device to a power transmission device according to another embodiment. This is a diagram showing an example of a coupling state index measurement method between a power transmission device and a power receiving device according to the third embodiment.

[0010] The embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. Although the embodiments describe multiple features, not all of these features are necessarily essential to the invention, and the features may be combined in any way. Furthermore, in the accompanying drawings, the same or similar configurations will be 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.

[0011] <First Embodiment> [System Configuration] 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 stand (Interface Surface) 300.

[0012] The detailed configurations of the power transmission device 100 and the power receiving device 200 will be described later with reference to Figures 2 and 3.

[0013] The power receiving device 200 is an electronic device that, while placed on the charging base 300, wirelessly receives power from the power transmitting device 100 to charge its built-in battery. The power transmitting device 100 is an electronic device that wirelessly transmits power to the power receiving device 200 while it is placed on the charging base 300. Since the charging base 300 constitutes part of the power transmitting device 100, in the following, when the power receiving device 200 is "placed on the charging base 300", it may be referred to as "placed on the power transmitting device 100". The spatial range in which the power receiving device 200 can receive power from the power transmitting device 100 is schematically shown in Figure 1 by the area of ​​the dotted line frame 400. The power receiving device 200 and the power transmitting device 100 may have functions to perform applications other than wireless charging. For example, the power receiving device 200 may be a smartphone, and the power transmitting device 100 may be an accessory device for charging the battery of the power receiving device 200. However, this disclosure is not limited to this example.

[0014] [Configuration of Power Transmission and Receiving Devices] Next, an example of the configuration of the power transmission device 100 will be described with reference to Figure 2. Figure 2 is a functional block diagram showing an example of the configuration of the power transmission device 100. The power transmission device 100 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 detection 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).

[0015] The control unit 101 controls the entire power transmission device 100 by executing a control program stored in the memory 106. The control unit 101 also performs power transmission control, including communication for equipment authentication within the power transmission device 100. Furthermore, the control unit 101 can perform control for executing applications other than wireless power transmission. The control unit 101 is configured to include one or more processors, such as a 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 execute predetermined processing. The control unit 101 can perform processes to store information that should be stored during the execution of various processes in the memory 106, and can also perform timing processes using a timer (not shown).

[0016] 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 the power supplied from the commercial power supply.

[0017] 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 power receiving device 200 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.

[0018] 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.

[0019] 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.

[0020] Alternatively, the power transmission unit 103 controls the intensity of the electromagnetic waves (power transmission) 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 power transmission) is controlled by the magnitude of the inverter output voltage or inverter output current.

[0021] 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 50 watts (W) of power to the charging section of the power receiving device 200 which complies with the WPC standard.

[0022] The first communication unit 104 is connected to the control unit 101 and the power transmission unit 103, and communicates with the power receiving device 200 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 power receiving device 200 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 power receiving device 200, and acquires the information transmitted by the power receiving device 200. 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.

[0023] In addition to the control program, the memory 106 can store information regarding the status of the power transmission device 100 and the power receiving device 200. This information regarding the status of the power transmission device 100 and the power receiving device 200 includes the power transmission value, the power reception value, etc. Information regarding the status of the power transmission device 100 is acquired by the control unit 101. Information regarding the status of the power receiving device 200 is acquired by the control unit of the power receiving device 200 and can be received by the first communication unit 104 or the second communication unit 109, which will be described later.

[0024] The detection unit 108 detects whether an object is placed on the power transmission device 100 based on the WPC standard. Specifically, the detection unit 108 detects whether an object is placed on the Interface Surface of the power transmission device 100. For example, the detection unit 108 detects at least one of the voltage value and current value of the power transmission coil 105 when the power transmission unit 103 transmits an Analog Ping according to the WPC standard via the power transmission coil 105. The detection unit 108 may also detect a change in impedance. The detection unit 108 can then determine that an object is placed on the power transmission device 100 if the voltage value falls below a predetermined voltage value or the current value exceeds a predetermined current value.

[0025] Whether this object is the power receiving device 200 or some other foreign object is determined by whether or not there is a predetermined response to the Digital Ping subsequently transmitted by the first communication unit 104. That is, if the power transmitting device 100 receives the predetermined response, it is determined that the object is the power receiving device 200; otherwise, it is determined that the object is something other than the power receiving device. The detection unit 108 is mainly an example of a state detection means for detecting whether the power receiving device is able to receive power from the power transmitting device.

[0026] Thus, in this disclosure, the placement of a power receiving device on a power transmitting device means that the power receiving device becomes capable of receiving power from the power transmitting device (for example, by being positioned in a location where it can receive power).

[0027] Here, it is conceivable that even when a power receiving device is mounted on a power transmitting device, it may not necessarily be in a state where it can receive power. For example, this could occur if the power receiving device is fitted with a cover, case, or other component that blocks or attenuates electromagnetic waves, or if there is an unintended component between the power transmitting device and the power receiving device that blocks or attenuates electromagnetic waves. The phrase "the power receiving device is mounted on the power transmitting device," which will be explained later using flowcharts, is merely one example of when the power receiving device becomes capable of receiving power from the power transmitting device.

[0028] Furthermore, the state in which a power receiving device is capable of receiving power is not limited to the state in which the power receiving device is mounted on the power transmitting device. For example, the state in which a power receiving device is capable of receiving power may be a state in which the power receiving device and the power transmitting device are in contact or in close proximity due to mechanical engagement, or the state in which the power receiving device is in contact with the power transmitting device by magnetic force.

[0029] In this disclosure, the state in which the power receiving device 200 is mounted on the power transmitting device 100 is used as a typical example of a state in which the power receiving device 200 is capable of receiving power, and this explanation will be provided accordingly.

[0030] The second communication unit 109 is connected to the control unit 101 and communicates with the power receiving device 200 using a standard different from the WPC standard. For example, the second communication unit 109 communicates with the power receiving device 200 using an antenna (not shown) different from the power 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). BLE can be any communication method compatible with Bluetooth standard version 4.0 or later. The frequency band used for power transmission from the power 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.

[0031] Regarding communication between the power transmission device 100 and the power receiving device 200, the power transmission device 100 may selectively use one of several communication standards to communicate with the power receiving device 200. For example, the following communication configurations using multiple communication standards selectively are possible: • Communication based on a first standard (WPC standard) between the first communication unit 104 of the power transmission device 100 and the first communication unit 204 of the power receiving device 200 (see Figure 3). • Communication based on a second standard (a standard other than the WPC standard) between the second communication unit 109 of the power transmission device 100 and the second communication unit 212 of the power receiving device 200 (see Figure 3).

[0032] 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 a speaker, and vibration of the power transmission device 100. The UI unit 110 is implemented using a liquid crystal panel, a speaker, a vibration motor, etc.

[0033] Next, an example of the 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 of the configuration of the power receiving device 200. The power receiving device 200 includes a control unit 201, a UI unit 202, a power receiving unit 203, a first communication unit 204, a power receiving antenna (power receiving coil) 205, a charging unit 206, a battery 207, and a memory 208. The power receiving device 200 further includes a detection unit 209 and a second communication unit 212. 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).

[0034] The control unit 201 controls each functional block element of the power receiving device 200 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 entire power receiving device 200 (for example, the entire smartphone) can be controlled in cooperation with the OS (Operating System) that the control unit 201 is running on. Alternatively, the control unit 201 is configured to include hardware such as an ASIC, or array circuits such as an FPGA compiled to execute predetermined processing. The control unit 201 stores information that should be stored during the execution of various processes in the memory 208, and is also capable of executing timing processing using a timer (not shown).

[0035] 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 power receiving device 200. The UI unit 202 is implemented using a liquid crystal panel, speaker, vibration motor, etc.

[0036] The power receiving unit 203 receives AC power (AC voltage and AC current) generated by electromagnetic induction based on electromagnetic waves radiated from the power transmitting antenna 105 of the power transmitting device 100 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 power receiving device 200. The rectifier unit converts the AC voltage and AC current from the power 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 for charging the battery 207 from the charging unit 206. The power receiving unit 203 is assumed to have the power supply capacity to output 50 watts (W) of power to the charging unit 206.

[0037] The first communication unit 204 communicates with the first communication unit 104 of the power transmission device 100 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 power transmission device 100. The first communication unit 204 performs load modulation, amplitude modulation, or backscatter modulation on the input electromagnetic waves and superimposes a signal related to the information to be transmitted to the power transmission device 100 onto the electromagnetic waves, thereby communicating with the power transmission device 100.

[0038] The memory 208 stores information regarding the status of the power transmission device 100 and the power receiving device 200, in addition to the control program. Information regarding the status of the power receiving device 200 is acquired by the control unit 201. Information regarding the status of the power transmission device 100 is acquired by the control unit 101 of the power transmission device 100 and can be received by the first communication unit 204 or the second communication unit 212, which will be described later.

[0039] The second communication unit 212 is connected to the control unit 201 and communicates with the power transmission device 100 using a standard different from the WPC standard. For example, the second communication unit 212 communicates with the power transmission device 100 using an antenna different from the receiving antenna 205. Examples of communication methods used by the second communication unit 212 include wireless LAN, BLE, NFC, etc. BLE can be any communication method compatible with Bluetooth standard version 4.0 or later. 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.

[0040] Regarding communication between the power transmission device 100 and the power receiving device 200, the power receiving device 200 may selectively use one of several communication standards to communicate with the power transmission device 100. For example, the following communication configurations using multiple communication standards selectively are possible: • Communication based on a first standard (WPC standard) between the first communication unit 104 of the power transmission device 100 and the first communication unit 204 of the power receiving device 200. • Communication based on a second standard (a standard other than the WPC standard) between the second communication unit 109 of the power transmission device 100 and the second communication unit 212 of the power receiving device 200.

[0041] The detection unit 209 detects that the power receiving device 200 is mounted on the power transmitting device 100 based on the WPC standard. The detection unit 209 detects, for example, at least one of the voltage value and current value of the power receiving coil 205 when the power receiving unit 203 receives a WPC standard Digital Ping via the power receiving coil 205. The detection unit 209 can determine, for example, that the power receiving device 200 is mounted on the power transmitting device 100 if the voltage value falls below a predetermined voltage threshold or the current value exceeds a predetermined current threshold.

[0042] In this wireless charging system, the power transmission device 100 and the power receiving device 200 perform wireless power transmission between the power transmission antenna 105 and the power receiving antenna 205 in accordance with the WPC standard. In the WPC standard, the level of load power agreed upon between the power receiving device 200 and the power transmission device 100 is defined by a value called Guaranteed Load Power (hereinafter referred to as "GP"). Load power is the power consumed by the load. For example, GP is the power value at which the output of the power receiving device 200 to the load is guaranteed even if the coupling state between the power receiving antenna 205 and the power transmission antenna 105 weakens and the power transmission efficiency decreases due to a change in the positional relationship between the power receiving device 200 and the power transmission device 100. In this specification, the coupling state between the power transmission antenna (power transmission coil) 105 and the power receiving antenna (power receiving coil) 205 may also be referred to as the coupling state between the power transmission device 100 and the power receiving device 200. The load of the power receiving device 200 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 that the positional relationship between the power receiving antenna 205 and the power transmitting antenna 105 changes.

[0043] In this case, even if the power transmission efficiency decreases, the power transmission device 100 performs power transmission control so that it can output 5 watts to the load of the power receiving device 200. Furthermore, the GP is determined by negotiations between the power transmission device 100 and the power receiving device 200. This disclosure is not limited to the GP, and this embodiment can be applied to any configuration in which power is transmitted and received at a power level determined by negotiations between the power transmission device 100 and the power receiving device 200.

[0044] [Method for detecting foreign objects during wireless power transmission] Next, we will explain the method for detecting foreign objects while the power transmission device 100 is wirelessly transmitting power to the power receiving device 200 in the MPP (Magnetic Power Profile) of the Qi standard. MPP is adopted in the Qi standard "Qi2". In the WPC standard, there are BPP (Baseline Power Profile) which transmits 5 watts or less of power to the power receiving device 200, EPP (Extended Power Profile) which transmits 15 watts or less of power, and the above-mentioned MPP. Here, a power profile is a set of features that defines the compliance level of the power transmission device or the power receiving device. MPP has the function of precisely fixing the power transmission device 100 and the power receiving device 200 in predetermined positions. Multiple means can be considered for precisely fixing the power transmission device 100 and the power receiving device 200 in predetermined positions. For example, the power transmission antenna (power transmission coil) 105 of the power transmission device 100 and the power receiving antenna (power receiving coil) 205 of the power receiving device 200 can be precisely opposed (facing directly) by using magnets built into the power transmission device 100 and the power receiving device 200, respectively. The magnets may be permanent magnets or electromagnets. MPP is an extended function of BPP and can be described as a profile (power profile) that uses magnets to align the power transmission device and the power receiving device.

[0045] During power transmission, power loss P occurs due to foreign objects present near the transmitting antenna 105 of the power transmission device 100 and the receiving antenna 205 of the power receiving device 200. ＦＯ P is calculated by the following (Equation 1). ＦＯ = P ＰＴ -P ＰＲ (Formula 1)

[0046] P in (Equation 1) ＰＴ This is the power transmitted by the power transmission device 100,

[0047]

[0048] That is the case.

[0049] In (Equation 2), V ＩＮis the input voltage (DC voltage) to the inverter of the power transmission device 100, and I ＩＮ is the input current (DC current) to the inverter of the power transmission device 100. That is, V ＩＮ I ＩＮ is the input power to the inverter of the power transmission device 100. V ＩＮ and I ＩＮ are measured by the power transmission device 100 at any time during power transmission.

[0050] P in (Equation 2) ｃｉｒｃｕｉｔ ｌｏｓｓ，ＴＸ is the loss in the power transmission circuit of the power transmission device 100. The loss is, for example, the loss due to the switching of the inverter in the power transmission circuit and the parasitic resistance, and the loss due to the parasitic resistance of each component. P ｃｉｒｃｕｉｔ ｌｏｓｓ，ＴＸ The value of is calculated in advance by measurement and held by the power transmission device 100 in the memory 106. Note that P ｃｉｒｃｕｉｔ ｌｏｓｓ，ＴＸ is not necessarily a constant. For example, P ｃｉｒｃｕｉｔ ｌｏｓｓ，ＴＸ is a function having I ＩＮ as a variable may be.

[0051] P in (Equation 2) ｃｏｉｌ ｌｏｓｓ，ＴＸ is the loss in the power transmission antenna 105 of the power transmission device 100 and is calculated by the following (Equation 3).

[0052]

[0053] In (Equation 3),

[0054]

[0055] and R ｃｏｉｌ ａｉｒ，ＴＸ is the resistance value of the power transmission antenna 105 at the switching frequency of the inverter in the power transmission circuit when the power receiving device is not facing. Also, I in (Equation 3) ＴＸ is the current flowing through the power transmission antenna 105.

[0056] In (Equation 4)

[0057]

[0058] and

[0059]

[0060] Furthermore, b in (Equation 3) ｃｏｉｌ The vertical axis is P ｃｏｉｌ ｌｏｓｓ，ＴＸ Take the horizontal axis and

[0061]

[0062] This represents the slope of the linear approximation curve in the graph drawn using this method (hereinafter referred to as the transmission antenna loss graph).

[0063]

[0064] This is the slope of the linear approximation curve of the transmission antenna loss graph when the system model's transmission device and the system model's receiving device are facing each other.

[0065] Here, the "system model power transmission device" refers to the reference power transmission device. Hereafter, in this specification, the "system model power transmission device" will be referred to as the reference power transmission device. Similarly, the "system model power receiving device" refers to the reference power receiving device. Hereafter, in this specification, the "system model power receiving device" will be referred to as the reference power receiving device.

[0066] In other words,

[0067]

[0068] This is the slope of the linear approximation curve of the transmission antenna loss graph when the reference transmission device and the reference reception device are facing each other. In this case, R ｃｏｉｌ ａｉｒ，ＴＸ This is the resistance value of the power transmission antenna of the reference power transmission device at the switching frequency of the inverter in the power transmission circuit of the reference power transmission device when the power receiving device is not facing it. ＴＸ This is the current flowing through the transmission antenna of the reference power transmission device.

[0069]

[0070] ​​This is the slope of the linear approximation curve of the transmission antenna loss graph when the reference transmission device and the power receiving device 200 are facing each other. In this case, R ｃｏｉｌ ａｉｒ，ＴＸ This is the resistance value of the power transmission antenna of the reference power transmission device at the switching frequency of the inverter in the power transmission circuit of the reference power transmission device when the power receiving device is not facing it. ＴＸ This is the current flowing through the transmission antenna of the reference power transmission device.

[0071]

[0072] and

[0073]

[0074] The value is calculated in advance by measurement.

[0075]

[0076] and

[0077]

[0078] g calculated from the value ｃｏｉｌ，ＴＸ The value of is stored in the memory 208 of the power receiving device 200. Also, g ｃｏｉｌ，ＴＸ The value is notified from the power receiving device 200 to the power transmitting device 100 during the Configuration phase or Negotiation phase described above, and is stored in the memory 106 of the power transmitting device 100.

[0079] b ｃｏｉｌ This is the slope of the linear approximation curve of the power transmission antenna loss graph when the power transmission device 100 and the reference power receiving device are facing each other. In this case, R ｃｏｉｌ ａｉｒ，ＴＸ This is the resistance value of the power transmission antenna 105 of the power transmission device 100 at the switching frequency of the inverter of the power transmission circuit of the power transmission device 100 when the power receiving device is not facing it. ＴＸ This is the current flowing through the power transmission antenna 105 of the power transmission device 100. ｃｏｉｌ The value is calculated in advance by measurement and stored in the memory 106 of the power transmission device 100.

[0080] ​​As described above, P ｃｏｉｌ ｌｏｓｓ，ＴＸ This is the current I flowing through the power transmission antenna 105 of the power transmission device 100. ＴＸ and, g ｃｏｉｌ，ＴＸ , b ｃｏｉｌ and R ｃｏｉｌ ａｉｒ，ＴＸ The current I is calculated by the power transmission device 100 using the above. ＴＸ This is measured periodically by the power transmission device 100 during power transmission. ｃｏｉｌ，ＴＸ , b ｃｏｉｌ and R ｃｏｉｌ ａｉｒ，ＴＸ It is held in the memory 106 of the power transmission device 100.

[0081] P in (Equation 2) ＦＭ ｌｏｓｓ This refers to the loss caused by metal components arranged around the two antennas when the transmitting antenna 105 of the power transmission device 100 and the receiving antenna 205 of the power receiving device 200 are facing each other. Hereafter, an integral part of a product including the power receiving device 200 or a product including the power transmission device 100 that may unintentionally generate heat when exposed to a power signal will be referred to as friendly metal. ＦＭ ｌｏｓｓ This is called friendly metal loss. Friendly metal loss is approximated by the following equation (5).

[0082]

[0083] In (Equation 5),

[0084]

[0085] And,

[0086]

[0087] That is the case.

[0088] In (Equation 6)

[0089]

[0090] and

[0091] ​​​​​

[0092] Furthermore, α in (Equation 5) ＦＭ The vertical axis is P ＦＭ ｌｏｓｓ Take the horizontal axis and

[0093]

[0094] This represents the slope of the linear approximation curve in the graph drawn using this method (hereinafter referred to as the friendly metal loss graph).

[0095] Similarly, in (Equation 7)

[0096]

[0097] and

[0098]

[0099] Furthermore, α in (Equation 5) ＦＭ，ＤＣ This represents the intercept of the linear approximation curve in the friendly metal loss graph.

[0100]

[0101] This is the slope of the linear approximation curve of the friendly metal loss graph when the reference transmission device and the reference reception device are facing each other.

[0102]

[0103] This is the intercept of the linear approximation curve of the friendly metal loss graph when the reference transmission device and the reference reception device are facing each other. In this case, I ＴＸ This is the current flowing through the transmission antenna of the reference power transmission device.

[0104]

[0105] This is the slope of the linear approximation curve of the friendly metal loss graph when the power transmission device 100 and the reference power receiving device are facing each other.

[0106]

[0107] ​This is the intercept of the linear approximation curve of the friendly metal loss graph when the power transmission device 100 and the reference power receiving device are facing each other. At this time, I ＴＸ This is the current flowing through the power transmission antenna of the power transmission device 100.

[0108]

[0109] ,

[0110]

[0111] ,

[0112]

[0113] and

[0114]

[0115] The values ​​were calculated in advance by measurement, and g was calculated from these values. ＦＭ and g ＦＭ，ＤＣ The value is stored in the memory 106 by the power transmission device 100.

[0116] α ＦＭ This is the slope of the linear approximation curve of the friendly metal loss graph when the reference power transmission device and the power receiving device 200 are facing each other. Also, α ＦＭ，ＤＣ This is the intercept of the linear approximation curve of the friendly metal loss graph when the reference power transmission device and the power receiving device 200 are facing each other. At this time, I ＴＸ This is the current flowing through the transmission antenna of the reference power transmission device. α ＦＭ and α ＦＭ，ＤＣ The value of is calculated in advance by measurement and stored in the memory 208 of the power receiving device 200. Also, α ＦＭ and α ＦＭ，ＤＣ The value is notified from the power receiving device 200 to the power transmitting device 100 during the Configuration phase or Negotiation phase described above, and is stored in the memory 106 of the power transmitting device 100.

[0117] As described above, P ＦＭ ｌｏｓｓ This is the current I flowing through the power transmission antenna 105 of the power transmission device 100. ＴＸ and, g ＦＭ ​, g ＦＭ，ＤＣ , α ＦＭ and α ＦＭ，ＤＣ are used to calculate the current I by the power transmission device 100. The current I ＴＸ is measured by the power transmission device 100 at any time during power transmission. g ＦＭ , g ＦＭ，ＤＣ , α ＦＭ and α ＦＭ，ＤＣ are stored in the memory 106 of the power transmission device 100. Also, P ＰＴ is calculated by the power transmission device 100 using (Equation 2), and the value is stored in the memory 106 by the power transmission device 100.

[0118] Next, P in (Equation 1) ＰＲ is the received power of the power receiving device 200,

[0119]

[0120] is.

[0121] In (Equation 8), V[[ID=3)]] ＲＥＣＴ is the output voltage (DC voltage) after being rectified in the rectifier circuit of the power receiving device 200, and I ＲＥＣＴ is the output current (DC current) after being rectified in the rectifier circuit of the power receiving device 200. That is, V ＲＥＣＴ I ＲＥＣＴ is the output power after being rectified in the rectifier circuit of the power receiving device 200. V ＲＥＣＴ and I ＲＥＣＴ are measured by the power receiving device 200 at any time during power transmission by the power transmission device 100.

[0122] P in (Equation 8) ｃｉｒｃｕｉｔ ｌｏｓｓ，ＲＸ is the loss in the power receiving circuit of the power receiving device 200. The loss is, for example, the loss due to switching of the rectifier circuit in the power receiving circuit, parasitic resistance, or the loss due to parasitic resistance of each component. P ｃｉｒｃｕｉｔ ｌｏｓｓ，ＲＸ The value of is calculated in advance by measurement and is held in the memory 208 of the power receiving device 200. Note that P ｃｉｒｃｕｉｔ ｌｏｓｓ，ＲＸ is not necessarily a constant. For example, P ｃｉｒｃｕｉｔ ｌｏｓｓ，ＲＸ is I ＲＥＣＴIt could also be a function that takes as a variable.

[0123] P in (Equation 8) ｃｏｉｌ ｌｏｓｓ，ＲＸ This is the loss in the receiving antenna 205 of the power receiving device 200, and is calculated by the following (Equation 9).

[0124]

[0125] In (Equation 9),

[0126]

[0127] And R ｃｏｉｌ ａｉｒ，ＲＸ This is the resistance value of the receiving antenna 205 at the switching frequency of the rectifier circuit of the receiving circuit of the receiving device 200 when the power transmission devices are not facing each other. ＲＥＣＴ This is as stated above.

[0128] In (Equation 10)

[0129]

[0130] and

[0131]

[0132] Furthermore, m in (Equation 9) ｃｏｉｌ The vertical axis is P ｃｏｉｌ ｌｏｓｓ，ＲＸ Take the horizontal axis and

[0133]

[0134] This represents the slope of the linear approximation curve in the graph drawn using this method (hereinafter referred to as the receiving antenna loss graph).

[0135]

[0136] This is the slope of the linear approximation curve of the receiving antenna loss graph when the reference power transmission device and the reference power receiving device are facing each other. In this case, R ｃｏｉｌ ａｉｒ，ＲＸ This is the resistance value of the receiving antenna of the reference power receiving device at the switching frequency of the rectifier circuit of the receiving circuit of the reference power receiving device, when the power transmitting device is not facing it.​​​​ＲＥＣＴ This is the current flowing through the rectifier circuit of the power receiving circuit of the reference power receiving device.

[0137]

[0138] This is the slope of the linear approximation curve of the receiving antenna loss graph when the power transmission device 100 and the reference power receiving device are facing each other. In this case, R ｃｏｉｌ ａｉｒ，ＲＸ This is the resistance value of the receiving antenna of the reference power receiving device at the switching frequency of the rectifier circuit of the receiving circuit of the reference power receiving device, when the power transmitting device is not facing it. ＲＥＣＴ This is the current flowing through the rectifier circuit of the power receiving circuit of the reference power receiving device.

[0139]

[0140] and

[0141]

[0142] The value is calculated in advance by measurement.

[0143]

[0144] and

[0145]

[0146] g calculated from the value ｃｏｉｌ，ＲＸ The value of is stored in the memory 106 of the power transmission device 100. Also, g ｃｏｉｌ，ＲＸ The value is notified from the power transmission device 100 to the power receiving device 200 before power transmission and is stored in the memory 208 of the power receiving device 200.

[0147] I understand ｃｏｉｌ This is the slope of the linear approximation curve of the receiving antenna loss graph when the reference power transmission device and the power receiving device 200 are facing each other. In this case, R ｃｏｉｌ ａｉｒ，ＲＸ This is the resistance value of the receiving antenna 205 of the receiving device 200 at the switching frequency of the rectifier circuit of the receiving circuit of the receiving device 200, when the power transmission devices are not facing each other. ＲＥＣＴ This is the current flowing through the rectifier circuit of the power receiving circuit of the power receiving device 200.​​ｃｏｉｌ The value is calculated in advance by measurement and stored in the memory 208 of the power receiving device 200.

[0148] As described above, P ｃｏｉｌ ｌｏｓｓ，ＲＸ This is the current I output from the rectifier circuit of the power receiving circuit of the power receiving device 200. ＲＥＣＴ and, g ｃｏｉｌ，ＲＸ , m ｃｏｉｌ and R ｃｏｉｌ ａｉｒ，ＲＸ The current I is calculated by the power receiving device 200 using the above. ＲＥＣＴ This is measured periodically by the power receiving device 200 while the power transmission device 100 is transmitting power. ｃｏｉｌ，ＲＸ , m ｃｏｉｌ and R ｃｏｉｌ ａｉｒ，ＲＸ This is stored in the memory 208 of the power receiving device 200.

[0149] Also, P ＰＲ This is calculated by the power receiving device 200 using (Equation 8).

[0150] While the power transmission device 100 is transmitting power wirelessly, the power receiving device 200 is P ＰＲ The power transmission device 100 is periodically notified of this. The power transmission device 100 will then... ＰＲ This is stored in memory 106.

[0151] The power transmission device 100 holds P in memory 106 ＰＴ and P ＰＲ Using (Equation 1), the power loss P due to foreign matter present near the transmitting antenna 105 of the power transmission device 100 and the receiving antenna 205 of the power receiving device 200 is calculated. ＦＯ Calculate P ＦＯ Since this changes when there are changes in the environment surrounding the power transmission antenna 105 of the power transmission device 100 and the power receiving antenna 205 of the power receiving device 200, the power transmission device 100 is P ＦＯ P is calculated periodically. ＦＯ If the object falls outside the predetermined range, the power transmission device 100 determines that there is a foreign object and reduces the transmitted power or stops the power transmission.

[0152] ​​​In this way, the power transmission device 100 can detect foreign objects present near the power transmission antenna 105 of the power transmission device 100 and the power receiving antenna 205 of the power receiving device 200 while transmitting power wirelessly. This foreign object detection method is called MPP Power Loss Accounting (MPLA). The parameters used in MPLA are called MPP Power Loss Accounting Parameters (PLAP). As mentioned above, PLAP is α ＦＭ , α ＦＭ，ＤＣ , g ｃｏｉｌ，ＴＸ , g ｃｏｉｌ，ＲＸ And so on.

[0153] PLAP may also be referred to as parameters related to foreign object detection (processing), parameters used for foreign object detection (processing), parameters related to foreign object detection (processing), parameters for detecting whether or not a foreign object is present, parameters for detecting a foreign object, etc. PLAP may also be referred to as parameters related to MPLA, parameters used in MPLA, parameters related to MPLA, etc.

[0154] [Measurement Method for the Coupling State Index Between the Transmitting Antenna and the Receiving Antenna] Next, we will explain the measurement method for the coupling state index between the transmitting antenna and the receiving antenna. In wireless power transmission, power is transmitted by electromagnetic coupling the transmitting antenna 105 and the receiving antenna 205. By passing an alternating current through the transmitting antenna 105 and changing the magnetic flux passing through the receiving antenna 205, a voltage is induced in the receiving antenna 205. Regarding the coupling coefficient (denoted as k or k value), which is an index representing the coupling state between the transmitting antenna and the receiving antenna, for example, when all (100%) of the magnetic flux generated by the transmitting antenna passes through the receiving antenna, it becomes "k = 1". Also, when 70% of the magnetic flux generated by the transmitting antenna passes through the receiving antenna, it becomes "k = 0.7". In this case, the remaining (30%) of the magnetic flux generated by the transmitting antenna becomes leakage flux. This is the magnetic flux generated by the transmitting antenna that did not pass through the receiving antenna. Therefore, when the coupling between the transmitting antenna and the receiving antenna is good and the k value is large, the power transmission efficiency from the transmitting device 100 to the receiving device 200 is high. Conversely, when the coupling is not good and the k value is small, the power transmission efficiency from the transmitting device 100 to the receiving device 200 is low.

[0155] Factors that cause a decrease in the coupling coefficient include the presence of foreign objects (such as metal fragments) between the transmitting and receiving antennas, and misalignment between the transmitting and receiving antennas. Alternatively, an increase in the distance between the transmitting and receiving antennas can be a contributing factor. If foreign objects are present between the transmitting and receiving antennas, heat may be generated in the foreign objects. Furthermore, misalignment or separation between the transmitting and receiving antennas increases leakage flux, which can generate significant noise in the surrounding environment. When the k value is small, appropriate control is necessary to achieve safer and higher-quality wireless power transmission. In this embodiment, in order to improve the detection accuracy of foreign objects and the detection accuracy when misalignment or distance (separation) is large, the transmitting device 100 and / or receiving device 200 perform a process to detect, calculate, or determine the coupling state (including the coupling coefficient) between the transmitting and receiving antennas.

[0156] Referring to Figure 23, a method for measuring the coupling state index between a transmitting antenna and a receiving antenna will be explained. Figure 23 is an equivalent circuit diagram illustrating an example of a measurement method for measuring the coupling state index.

[0157] The definitions of various quantities related to the power transmission antenna (power transmission coil) on the primary side (power transmission device 100) are shown below: • r1: Winding resistance of the power transmission antenna. • L1: Self-inductance of the power transmission antenna. • V1: Power transmission voltage (input voltage) applied to the power transmission antenna as measured by the power transmission device 100.

[0158] Furthermore, the definitions of various quantities related to the receiving antenna (receiving coil) on the secondary side (receiving device 200) are shown below: • r2: Winding resistance of the receiving antenna. • L2: Self-inductance of the receiving antenna. • V2: Receiving voltage (output voltage) applied to the receiving antenna as measured by the receiving device 200.

[0159] The coupling coefficient k between the transmitting antenna and the receiving antenna can be calculated by the following equation (Equation 11): k = (V2 / V1) * √(L1 / L2) (Equation 11)

[0160] The value of the coupling coefficient k is sometimes referred to as the "k-value."

[0161] When the power transmission device 100 calculates the coupling coefficient k, the power receiving device 200 notifies the power transmission device 100 of the measured receiving voltage V2 and the value of the self-inductance L2 of the receiving antenna that the power receiving device 200 has stored in advance. The power transmission device 100 calculates the k value using the measured transmission voltage V1, the value of the self-inductance L1 of the transmission antenna that it has stored in advance, and the received voltage V2 and the value of the self-inductance L2 received from the power receiving device 200. Alternatively, the power receiving device 200 notifies the power transmission device 100 of a constant calculated using all or either of L1 and L2, and V2. The power transmission device 100 can then calculate the k value using the constant and V2 received from the power receiving device 200 and the transmission voltage V1 measured by the power transmission device 100.

[0162] On the other hand, when the receiving device 200 calculates the coupling coefficient k, the transmitting device 100 notifies the receiving device 200 of the measured transmitting voltage V1 and the value of the self-inductance L1 of the transmitting antenna, which is stored in advance. The receiving device 200 calculates the k value using the measured receiving voltage V2, the value of the self-inductance L2 of the receiving antenna, which is stored in advance, and the values ​​of the transmitting voltage V1 and self-inductance L1 received from the transmitting device 100. Alternatively, the transmitting device 100 notifies the receiving device 200 of a constant calculated using all or either of L1 and L2, and V1. The receiving device 200 can then calculate the k value using the constant and V1 received from the transmitting device 100 and the receiving voltage V2 measured by the receiving device 200.

[0163] The transmission voltage V1 is either actually measured by the transmission device 100 at the voltage applied to the transmission antenna, or calculated by the transmission device 100 from the set value of the transmission power. Alternatively, the transmission voltage V1 may be set to the transmission voltage setting value at the time of transmission. Furthermore, the transmission voltage V1 applied to the transmission antenna 105 can be determined from the transmission voltage (denoted as V3) applied to the circuit (e.g., inverter) of the transmission unit 103 of the transmission device 100 and the voltage across the resonant capacitor (not shown) connected to the transmission antenna 105. Here, the transmission voltage V3 applied to the circuit of the transmission unit 103 of the transmission device 100 is, for example, the inverter input voltage input to the inverter of the transmission unit 103 of the transmission device 100, or the inverter output voltage output of the inverter. In this case, the transmission voltage V3 may also be calculated by the transmission device 100 from the set value of the transmission power. Alternatively, the power transmission device 100 may actually measure the transmission voltage V3 and the voltage across the resonant capacitor (not shown) connected to the power transmission antenna 105, and use these to determine the transmission voltage V1. Alternatively, the power transmission device 100 may transmit the measured transmission voltage V3 and the voltage across the resonant capacitor (not shown) connected to the power transmission antenna 105 to the power receiving device 200. The power receiving device 200 may then calculate the k value by determining the transmission voltage V1 using the received voltage value.

[0164] Furthermore, when the power transmission device 100 or the power receiving device 200 performs coupling state index measurement between the power transmission antenna and the power receiving antenna, the power receiving device 200 may control the terminals of the power receiving antenna 205 to be in an open state. Since the coupling state index measurement between the power transmission antenna and the power receiving antenna is not affected by the power receiving unit 203, the charging unit 206, and the battery 207, it becomes possible to measure the coupling coefficient k with higher accuracy. In addition, the power receiving voltage V2 applied to the power receiving antenna 205 can be determined from the power receiving voltage (denoted as V4) applied to the circuit (e.g., rectifier) ​​of the power receiving unit 203 of the power receiving device 200 and the voltage across the resonant capacitor (not shown) connected to the power receiving antenna 205. Here, the power receiving voltage V4 applied to the circuit of the power receiving unit 203 of the power receiving device 200 is, for example, the rectifier input voltage input to the rectifier of the power receiving unit 203 of the power receiving device 200. Alternatively, the receiving voltage V2 applied to the receiving antenna 205 can be determined from the receiving voltage (denoted as V5) of the circuit (e.g., rectifier) ​​of the receiving section 203 of the power receiving device 200 and the voltage across the resonant capacitor (not shown) connected to the receiving antenna 205. Here, the receiving voltage V5 applied to the circuit of the receiving section 203 of the power receiving device 200 is, for example, the rectifier output voltage output from the rectifier section of the receiving section 203 of the power receiving device 200. In this case, the power receiving device 200 may actually measure the receiving voltage V4 and the voltage across the resonant capacitor (not shown) connected to the receiving antenna 205 and use them to determine the receiving voltage V2. Alternatively, the power receiving device 200 may actually measure the receiving voltage V5 and the voltage across the resonant capacitor (not shown) connected to the receiving antenna 205 and use them to determine the receiving voltage V2. Alternatively, the power receiving device 200 may transmit the measured power receiving voltage V4 and the voltage across the resonant capacitor (not shown) connected to the power receiving antenna 205 to the power transmitting device 100. The power transmitting device 100 may then calculate the k value by determining the power receiving voltage V2 using the received voltage value. Alternatively, the power receiving device 200 may transmit the measured power receiving voltage V5 and the voltage across the resonant capacitor (not shown) connected to the power receiving antenna 205 to the power transmitting device 100.The power transmission device 100 may then calculate the k value by determining the receiving voltage V2 using the received voltage value.

[0165] Alternatively, when the power transmission device 100 or the power receiving device 200 performs coupling state index measurement between the power transmission antenna and the power receiving antenna, the power receiving device 200 may be controlled to be in a light load state or a load-connected state. By keeping the load state of the power receiving device 200 constant, it becomes possible to measure the coupling coefficient k with higher accuracy. Alternatively, the power transmission device 100 or the power receiving device 200 may be controlled to perform coupling state index measurement between the power transmission antenna and the power receiving antenna in both the light load state and the load-connected state of the power receiving device 200. Alternatively, the power transmission device 100 or the power receiving device 200 may be controlled to perform coupling state index measurement between the power transmission antenna and the power receiving antenna in each of three or more load states. By measuring the coupling state in multiple load states of the power receiving device 200 and determining the coupling state based on these measurements, the coupling state can be determined with higher accuracy.

[0166] In addition to the coupling coefficient, there are several other quantities that can be used to represent the electromagnetic coupling state between the transmitting antenna and the receiving antenna. In this embodiment, these are collectively referred to as "coupling state indices." Each coupling state index has a value that corresponds to the electromagnetic coupling state between the transmitting antenna and the receiving antenna.

[0167] The contents of this embodiment can be similarly applied when using coupling state indicators other than coupling coefficients.

[0168] For example, one method for calculating the coupling state index is to use the transmission voltage V3 applied to the circuit (e.g., inverter) of the transmission unit 103 of the power transmission device 100 and the receiving voltage V4 applied to the circuit (e.g., rectifier) ​​of the receiving unit 203 of the power receiving device 200. Here, the transmission voltage V3 applied to the circuit of the transmission unit 103 of the power transmission device 100 is, for example, the inverter input voltage input to the inverter of the transmission unit 103 of the power transmission device 100, or the inverter output voltage output by the inverter. The receiving voltage V4 applied to the circuit of the receiving unit 203 of the power receiving device 200 is, for example, the rectifier input voltage input to the rectifier of the receiving unit 203 of the power receiving device 200. Using these, the coupling state index between the power transmission antenna and the power receiving antenna can be calculated. Alternatively, the coupling state index between the transmitting antenna and the receiving antenna can be calculated using the transmission voltage V3 applied to the circuit (e.g., inverter) of the transmitting unit 103 of the transmitting device 100 and the receiving voltage V5 of the circuit (e.g., rectifier) ​​of the receiving unit 203 of the receiving device 200. Here, the receiving voltage V5 applied to the circuit of the receiving unit 203 of the receiving device 200 is, for example, the rectifier output voltage output from the rectifier of the receiving unit 203 of the receiving device 200. Alternatively, the receiving voltage V5 applied to the circuit of the receiving unit 203 of the receiving device 200 is the voltage applied to the load (charging unit, battery). The transmitting device 100 notifies the receiving device 200 of the transmission voltage V3, and the receiving device 200 can calculate the coupling state index using the notified V3 and V4 or V5. At this time, the power transmission device 100 notifies the power receiving device 200 of a constant calculated using the electrical characteristics (e.g., L1) of the power transmission antenna, and the power receiving device 200 can calculate a coupling state index using this constant.

[0169] Alternatively, the receiving device 200 notifies the transmitting device 100 of the receiving voltage V4 or V5, and the transmitting device 100 calculates the value of the coupling state index using the notified V4 or V5 and V3. At this time, the receiving device 200 also notifies the transmitting device 100 of a constant calculated using the electrical characteristics of the receiving antenna (e.g., L2), and the transmitting device 100 can calculate the coupling state index using this constant.

[0170] The power transmission device 100 and the power receiving device 200 exchange information such as the voltage values ​​V1 to V5, the values ​​of the self-inductances L1 and L2, and / or constants representing the electrical characteristics of the power transmission antenna and the power receiving antenna. The timing of voltage value measurement and the timing of transmission and reception of each piece of information will be explained below.

[0171] The measurement of each voltage value is performed, for example, during the Ping phase. During the Ping phase, the power transmission device 100 sends a Digital Ping to the power receiving device 200. Therefore, any of the voltage values ​​V1, V2, V3, V4, and V5 that are generated when the Digital Ping is sent can be used. During the Ping phase, the power transmission device 100 or the power receiving device 200 measures any of the values ​​from V1 to V5 and stores them in memory 106 or memory 208. Alternatively, the power transmission device 100 sends a predetermined packet to the power receiving device 200 to notify it of the timing for measuring the voltage value. Upon receiving the predetermined packet, the power receiving device 200 measures any of the voltage values ​​V2, V4, and V5. The power receiving device 200 measures any of the values ​​V2, V4, and V5 and stores them in memory 208. Alternatively, the power receiving device 200 transmits a predetermined packet to the power transmitting device 100 to notify it of the timing for measuring the voltage value. Upon receiving the predetermined packet, the power transmitting device 100 measures either the voltage value of V1 or V3. The power transmitting device 100 measures either the value of V1 or V3 and stores it in the memory 106.

[0172] The power transmission device 100 sends a predetermined transmission request packet to the power receiving device 200 to request the transmission of a packet containing information on any or all of the voltage values ​​of V2, V4, and V5. Upon receiving the transmission request packet, the power receiving device 200 sends a predetermined packet containing information on any or all of the voltage values ​​of V2, V4, and V5 to the power transmission device 100. The power transmission device 100 receives the predetermined packet containing information on any or all of the voltage values ​​of V2, V4, and V5 notified by the power receiving device 200 and stores the information in the memory 106. The information contained in the predetermined packet may include not only the voltage of the power receiving device 200, but also the received power, the requested received power value, the value of the self-inductance L2, and constants calculated using the electrical characteristics of the receiving antenna. Additionally or alternatively, the information contained in the predetermined packet may include information regarding the temperature of the power receiving device 200. The power transmission device 100 receives the information from the power receiving device 200 and can perform more appropriate control using the information and the calculated coupling state index. The power transmission device 100 can be notified of the information from the power receiving device 200 using a Signal Strength data packet as a predetermined packet. Alternatively, the predetermined packet may be an Identification data packet or an Extended Identification data packet in the Configuration phase. Alternatively, the predetermined packet may be a Configuration data packet. Alternatively, the predetermined packet may be a packet in the Calibration phase or Power Transfer phase. In other words, the predetermined packet may be RP1, RP2, or RP0. This disclosure is not limited to the example in which the voltage value generated when the power transmission device 100 transmits a Digital Ping is used. Any voltage value from V1 to V5 generated when the power transmission device 100 transmits an Analog Ping in the Ping phase may be used. Alternatively, any voltage value from V1 to V5 generated when the power transmission device 100 transmits power to the power receiving device 200 in the Power Transfer phase may be used.

[0173] The power receiving device 200 sends a predetermined transmission request packet to the power transmitting device 100 to request the transmission of a packet containing information on one or all of the voltage values ​​of V1 and V3. Upon receiving the transmission request packet, the power transmitting device 100 sends a predetermined packet containing information on one or all of the voltage values ​​of V1 and V3 to the power receiving device 200.

[0174] The power receiving device 200 receives a predetermined packet containing information on one or all of the voltage values ​​V1 and V3 notified by the power transmitting device 100, and stores this information in the memory 208. The information contained in the predetermined packet may include not only the voltage of the power transmitting device 100, but also information such as the power transmission value, the power transmissionable value, the value of the self-inductance L1, and constants calculated using the electrical characteristics of the power transmitting antenna. The power receiving device 200 receives this information from the power transmitting device 100 and can perform more appropriate control using this information and the coupling state index it calculates. In addition, the power transmitting device 100 can notify the power receiving device 200 of information using a Power Transmitter Capabilities (CAP) data packet as a predetermined packet. Alternatively, information from the power transmission device 100 can be notified to the power receiving device 200 using a predetermined packet, namely a Power Transmitter Identification (ID) data packet. This disclosure is not limited to the example using voltage values ​​generated when the power transmission device 100 transmits a Digital Ping. Any voltage value from V1 to V5 generated when the power transmission device 100 transmits an Analog Ping in the Ping phase may be used. Alternatively, any voltage value from V1 to V5 generated when the power transmission device 100 transmits power to the power receiving device 200 in the Power Transfer phase may be used.

[0175] When measuring the coupling state index between the transmitting antenna and the receiving antenna, the power receiving device 200 may be controlled so that the terminals of the circuit consisting of the receiving antenna 205 and the resonant capacitor connected to the receiving antenna 205 are open. This prevents the power receiving unit 203, the charging unit 206, and the battery 207 from influencing the coupling state index measurement between the transmitting antenna and the receiving antenna, thus enabling more accurate measurement of the coupling state index.

[0176] [Processing of the Power Receiving Device] Figure 4 is a flowchart showing an example of wireless power transmission processing based on the Qi standard by the power receiving device 200. In this embodiment, an example using MPP as the power profile is shown. This processing can be realized, for example, by the control unit 201 of the power receiving device 200 executing a program read from the memory 208. At least a part of the following procedure may be realized by hardware. In this case, the hardware can be realized, for example, by automatically generating a dedicated circuit using a gate array circuit such as an FPGA from a program to realize each processing step using a predetermined compiler.

[0177] In S401, the power receiving device 200 performs the processing defined as the Ping phase of the Qi standard and waits for itself to be placed on the power transmitting device 100. The power receiving device 200 detects that it has been placed on the power transmitting device 100, for example, by detecting a Digital Ping from the power transmitting device 100. Once the power receiving device 200 receives a Digital Ping from the power transmitting device 100, it sends a Signal Strength (SIG) data packet to the power transmitting device 100.

[0178] In S402, the power receiving device 200 executes the process defined as the Configuration phase of the Qi standard. In the Configuration phase, the power receiving device 200 transmits an Identification data package (ID Package) to the power transmitting device 100. The ID Package contains the Manufacturer Code and Basic Device ID, which are individual identification information for the power receiving device 200, as well as information elements that can identify the version of the corresponding Qi standard.

[0179] The power receiving device 200 may transmit its identification information to the power transmitting device 100 using an Extended Identification data package (XID Package). The power receiving device 200 also transmits a Configuration data package to the power transmitting device 100. The Configuration data package contains the following capability information (equipment configuration information) of the power receiving device 200: - Information that allows the power receiving device 200 to identify the version of the Qi standard it supports. - Maximum Power Value or Reference Power, which is a value that identifies the maximum power that the power receiving device 200 can supply to the load. - Information indicating whether the power receiving device 200 has the Qi standard Negotiation function. - Parameters used in frequency shift modulation, which is a communication modulation method used when the power transmission device 100 transmits information to the power receiving device 200.

[0180] However, this information is merely an example, and the identification information and capability information of the power receiving device 200 may be replaced by other information or may include other information. For example, the identification information may be any other identification information that can identify an individual power receiving device 200, such as a Wireless Power ID. Furthermore, the power receiving device 200 may transmit the identification information and capability information by a method other than the communication in the Configuration phase of the Qi standard.

[0181] Here, the receiving device 200 notifies the transmitting device 100 of the power profile information of the Qi standard supported by its device, including this information in either an ID Packet, an XID Packet, or a Configuration data pack. The receiving device 200 also uses one of these packets to notify the transmitting device 100 of the parameters necessary for estimating, calculating, or determining the coupling state index between the transmitting coil 105 of the transmitting device 100 and the receiving coil 205 of the receiving device 200. The parameters necessary for estimating, calculating, or determining the coupling state index are, for example, as described in the "Method for Measuring the Coupling State Index Between a Transmitting Antenna and a Receiving Antenna" above.

[0182] Upon receiving this notification, the power transmission device 100 compares the Qi standard power profile information supported by the power receiving device 200 with the Qi standard power profile supported by the power transmission device 100 to determine which power profile to use. In this case, MPP will be used as the power profile.

[0183] When the power receiving device 200 transmits identification information and capacity information, in S403 it initiates communication in the Negotiation phase as defined by the Qi standard. In the Negotiation phase, PLAP information is sent and received and the power transmission is negotiated between the power transmitting device 100 and the power receiving device 200.

[0184] Figure 5 is a flowchart showing a detailed example of processing in the Negotiation phase by the power receiving device 200.

[0185] First, in S501, the power receiving device 200 notifies the power transmitting device 100 of its capacity information. For notifying the capacity information, for example, the Extended Power Receiver Capabilities packet of the Qi standard can be used. Here, the capacity information of the power receiving device 200 refers to the minimum required power received value, etc.

[0186] Next, in S502, the power receiving device 200 requests capacity information from the power transmitting device 100. For example, a Get Request [ECAP] packet can be used to request capacity information.

[0187] In S503, the power receiving device 200 receives capability information of the power transmitting device 100, which has been transmitted from the power transmitting device 100 in response to a request from the power receiving device 200. The power transmitting device 100 notifies the capability information, for example, using an Extended Power Transmitter Extended Capabilities packet. Here, the capability information of the power transmitting device 100 includes the maximum power that can be transmitted, the range of power that can be transmitted, etc.

[0188] In S504, the power receiving device 200 requests a PLAP (Planning and Application Processing) from the power transmitting device 100 regarding the power transmitting device 100. For example, a Get Request [PLAP] packet can be used to request the PLAP.

[0189] In S505, the power receiving device 200 receives the PLAP of the power transmitting device 100, which was sent from the power transmitting device 100 in response to a request from the power receiving device 200. For sending (notifying) the PLAP, for example, a PLAP packet can be used. Here, the PLAP is, for example, the g described in the explanation of MPLA. ｃｏｉｌ，ＲＸ That is the case.

[0190] In S506, the power receiving device 200 notifies the power transmitting device 100 of the PLAP of the power receiving device 200. Here, the power receiving device 200 stores the information (PLAP) in a single packet and notifies it. For example, a PLAP packet can be used to notify the PLAP.

[0191] Here, an example of a PLAP packet transmitted by the power receiving device 200 to the power transmitting device 100 is shown in Figure 7. In Figure 7, the overall data (payload) structure 700 of the PLAP packet is shown.

[0192] Bits 701 (Alpha_FM), 702 (Alpha_FM_DC), and 703 (g_coil_TX) are the α described in the MPLA explanation, respectively. ＦＭ , α ＦＭ，ＤＣ and g ｃｏｉｌ，ＴＸ This is the bit that stores the value of α. ＦＭ , α ＦＭ，ＤＣ and g ｃｏｉｌ，ＴＸThis is the PLAP of the power receiving device 200. In this specification, parentheses around bits indicate field names. The field names listed are for illustrative purposes only.

[0193] Bit 711 (More) indicates whether there are any other PLAP packets (PLAPs) to be notified besides this packet. For example, if bit 711 is 1, it indicates that there are other PLAP packets to be notified besides this packet, and if it is 0, it indicates that there are no other PLAP packets to be notified besides this packet. The meanings of "1" and "0" may be reversed.

[0194] Bits 712 (Condition_Min), 713 (Condition_Max), and 714 (Condition) specify the conditions under which the power transmission device 100 will use the PLAP stored in this PLAP packet. As described above, PLAP is α ＦＭ , α ＦＭ，ＤＣ and g ｃｏｉｌ，ＴＸ Figure 8 shows an example of the contents of the information stored in bits 712, 713, and 714.

[0195] The following describes an example of the structure of a PLAP packet using Figures 7 and 8.

[0196] Bit 714 is a bit that stores the type of condition. Figure 8 shows the contents of the condition type 814. Bit 712, for example, if it is 0, indicates that the type of condition is the temperature of the power transmission device 100. Also, if bit 712, for example, if it is 1, indicates that the type of condition is the power transmitted by the power transmission device 100. Also, if bit 712, for example, if it is 2, indicates that the type of condition is the coupling coefficient between the power transmission coil 105 of the power transmission device 100 and the power receiving coil 205 of the power receiving device 200. As shown in Figure 8, the conditions set (specified) are the temperature of the power transmission device 100, the power transmitted by the power transmission device 100, and the coupling coefficient between the power transmission coil 105 of the power transmission device 100 and the power receiving coil 205 of the power receiving device 200. If no conditions are set and PLAP are each set as a single constant, the power receiving device 200 selects and stores 3 as the condition. When 3 is selected for the condition, the values ​​stored in bits 713 and 712, described later, are ignored.

[0197] In this embodiment, when the power receiving device 200 notifies the power transmitting device 100 of multiple PLAP packets, the type of condition (Condition) is the same for all of them. That is, if the Condition is set to 0 (temperature) in the first PLAP packet, the Condition of the PLAP packets notified thereafter will also be set to 0 (temperature), and there will be only one type of condition.

[0198] Bit 713 sets the upper limit of the Condition selected in bit 714. Figure 8 shows the contents of bit 713 for the upper limit of the Condition. When 0 (temperature) is selected for Condition, bit 713 indicates, for example, that if it is 0, the upper limit is 30°C; if it is 1, the upper limit is 60°C; and if it is 2, the upper limit is 90°C. When 1 (transmission power) is selected for Condition, bit 713 indicates, for example, that if it is 0, the upper limit is 5W; if it is 1, the upper limit is 25W; and if it is 2, the upper limit is 50W. When 2 (coupling coefficient) is selected for Condition, bit 713 indicates, for example, that if it is 0, the upper limit is 0.7; if it is 1, the upper limit is 0.8; and if it is 2, the upper limit is 0.9. Furthermore, if bit 713 is, for example, 3, then no upper limit is set regardless of whether 0, 1, or 2 is selected in Condition. Thus, the content of the upper limit differs depending on the Condition selected in bit 714.

[0199] Bit 712 sets the lower limit of the Condition selected in bit 714. Figure 8 shows the contents of bit 712 for the lower limit of the Condition. When 0 (temperature) is selected for Condition, bit 712 indicates, for example, that if it is 0, the lower limit is 30°C; if it is 1, the lower limit is 60°C; and if it is 2, the lower limit is 90°C. When 1 (power transmission) is selected for Condition, bit 712 indicates, for example, that if it is 0, the lower limit is 5W; if it is 1, the lower limit is 25W; and if it is 2, the lower limit is 50W. When 2 (coupling coefficient) is selected for Condition, bit 712 indicates, for example, that if it is 0, the lower limit is 0.7; if it is 1, the lower limit is 0.8; and if it is 2, the lower limit is 0.9. Furthermore, if bit 712 is, for example, 3, then no lower limit is set regardless of whether 0, 1, or 2 is selected in Condition. Thus, the content of the lower limit differs depending on the Condition selected in bit 714.

[0200] The power receiving device 200 uses multiple such PLAP packets to specify the conditions for use and notifies the power transmitting device 100 of the PLAP. The power receiving device 200, for example, uses the four PLAP packets shown in Figure 9A to send a PLAP (α ＦＭ , α ＦＭ，ＤＣ and g ｃｏｉｌ，ＴＸLet's assume that the power transmission device 100 is notified of the conditions for using each PLAP. Then, the power transmission device 100 uses each PLAP under the conditions shown in Figure 9B to detect foreign objects. Based on the contents shown in Figures 7 and 8, the PLAP packet in sequence "1" shown in Figure 9A corresponds to the PLAP with the condition "greater than 90°C" shown in Figure 9B. Similarly, the PLAP packet in sequence "2" shown in Figure 9A corresponds to the PLAP with the condition "30°C or less" shown in Figure 9B. Also, the PLAP packet in sequence "3" shown in Figure 9A corresponds to the PLAP with the condition "greater than 60°C, 90°C or less" shown in Figure 9B. Also, the PLAP packet in sequence "4" shown in Figure 9A corresponds to the PLAP with the condition "greater than 30°C, 60°C or less" shown in Figure 9B. In this way, the power receiving device 200 transmits PLAP packets to the power transmitting device 100 for each of the multiple temperature ranges indicated by the multiple conditions, thereby transmitting a separate PLAP to the power transmitting device 100 for each of the multiple temperature ranges indicated by the multiple conditions. As a result, the power transmitting device 100 can perform foreign object detection using a separate PLAP for each of the multiple temperature ranges.

[0201] Furthermore, when a transmission power range or coupling coefficient range is specified as a condition, the receiving device 200 transmits individual PLAPs to the transmission device 100 for each of the multiple transmission power ranges or coupling coefficient ranges indicated by the multiple conditions. This allows the transmission device 100 to perform foreign object detection using individual PLAPs for each of the multiple transmission power ranges or coupling coefficient ranges.

[0202] The temperature range, power transmission range, and coupling coefficient range described above are examples of the states related to this disclosure and may be referred to as environmental states, environmental conditions, etc. The states (environmental states, environmental conditions) can be said to be states (conditions) relating to the temperature, power transmission, and / or coupling state index of the power transmission device 100 and / or power receiving device 200.

[0203] Next, another example of a PLAP packet will be explained using Figures 10, 11, 12A, and 12B.

[0204] Figure 10 shows another example of the structure of a PLAP packet. In Figure 10, the entire data (payload) structure of a PLAP packet is shown.

[0205] Bits 1001, 1002, 1003, and 1011 are identical to bits 701, 702, 703, and 711 shown in Figure 7, respectively.

[0206] Bits 1012 (Condition_Max) and 1013 (Condition) specify the conditions under which the power transmission device 100 will use the PLAP stored in this PLAP packet. An example of the contents of the information stored in bits 1012 and 1013 is shown in Figure 11.

[0207] Bit 1013 is a bit that stores the type of condition. In Figure 11, the contents of the condition type 1113 are shown. For example, if bit 1013 is 0, it indicates that the type of condition is the temperature of the power transmission device 100. Also, if bit 1013 is 1, it indicates that the type of condition is the power transmitted by the power transmission device 100. Also, if bit 1013 is 2, it indicates that the type of condition is the coupling coefficient between the power transmission coil 105 of the power transmission device 100 and the power receiving coil 205 of the power receiving device 200. As shown in Figure 11, the conditions are set to the temperature of the power transmission device 100, the power transmitted by the power transmission device 100, and the coupling coefficient between the power transmission coil 105 of the power transmission device 100 and the power receiving coil 205 of the power receiving device 200. If no conditions are set and PLAP are each set as a single constant, the power receiving device 200 selects and stores 3 as the condition. When 3 is selected for the condition, the value stored in bit 1012, described later, is ignored.

[0208] Bit 1012 is a bit that sets the upper limit of the Condition selected in bit 1013. Figure 11 shows the contents of the upper limit of the Condition. If 0 (temperature) is selected for Condition, bit 1012 will store, for example, "upper limit (T [°C]) ÷ 4". If 1 (power transmission) is selected for Condition, bit 1012 will store, for example, "upper limit (P [W]) ÷ 2". If 2 (coupling coefficient) is selected for Condition, bit 1012 will store, for example, "upper limit (k) × 60 - 30". Note that if bit 1012 is, for example, 31, no upper limit will be set regardless of whether 0, 1, or 2 is selected for Condition. Thus, the contents of the upper limit differ depending on the Condition selected in bit 1013.

[0209] In this example, there is no bit to set the lower limit of the Condition, but the power transmission device 100 will fill in the lower limit. When the power transmission device 100 receives multiple PLAP packets from the power receiving device 200, the lower limit of the Condition of a given PLAP packet (hereinafter referred to as "this packet") is as follows: That is, the lower limit is the largest value among the upper limits of the Condition set in other PLAP packets that is less than the upper limit of the Condition of this packet. The power transmission device 100 will fill in the lower limit of the Condition of each PLAP packet after it has finished receiving all PLAP packets from the power receiving device 200.

[0210] The power receiving device 200 uses multiple such PLAP packets to specify the conditions for use and notifies the power transmitting device 100 of the PLAP. The power receiving device 200, for example, uses the four PLAP packets shown in Figure 12A to send a PLAP (α ＦＭ , α ＦＭ，ＤＣ and g ｃｏｉｌ，ＴＸAssume that the conditions for using each PLAP are notified to the power transmission device 100. Then, the power transmission device 100 uses each PLAP under the conditions shown in Figure 12B to perform foreign object detection. Note that Condition_Min shown in Figure 12A is a value supplemented by the power transmission device 100. Based on the contents shown in Figures 10 and 11, the PLAP packet in sequence "1" shown in Figure 12A corresponds to the PLAP with the condition "greater than 88°C" shown in Figure 12B. Similarly, the PLAP packet in sequence "2" shown in Figure 12A corresponds to the PLAP with the condition "28°C or less" shown in Figure 12B. Also, the PLAP packet in sequence "3" shown in Figure 12A corresponds to the PLAP with the condition "greater than 60°C, 80°C or less" shown in Figure 12B. Furthermore, the PLAP packet in sequence "4" shown in Figure 12A corresponds to the PLAP packet with the condition "greater than 28°C, 60°C or less" shown in Figure 12B. In this way, the power receiving device 200 transmits PLAP packets to the power transmitting device 100 for each of the multiple temperature ranges indicated by the multiple conditions, thereby transmitting a separate PLAP packet to the power transmitting device 100 for each of the multiple temperature ranges indicated by the multiple conditions. As a result, the power transmitting device 100 can perform foreign object detection using a separate PLAP packet for each of the multiple temperature ranges.

[0211] Furthermore, when a transmission power range or coupling coefficient range is specified as a condition, the receiving device 200 transmits individual PLAPs to the transmission device 100 for each of the multiple transmission power ranges or coupling coefficient ranges indicated by the multiple conditions. This allows the transmission device 100 to perform foreign object detection using individual PLAPs for each of the multiple transmission power ranges or coupling coefficient ranges.

[0212] The temperature range, power transmission range, and coupling coefficient range described above are examples of the states related to this disclosure and may be referred to as environmental states, environmental conditions, etc. The states (environmental states, environmental conditions) can be said to be states (conditions) relating to the temperature, power transmission, and / or coupling state index of the power transmission device 100 and / or power receiving device 200.

[0213] The above describes an example in which the power receiving device 200 notifies the upper limit of the Condition and the power transmitting device 100 supplements the lower limit of the Condition. However, this disclosure is not limited to this example, and the power receiving device 200 may notify the lower limit of the Condition and the power transmitting device 100 supplements the upper limit of the Condition. In this case, in Figures 10 and 11, Condition_Max is replaced with Condition_Min.

[0214] Further examples of PLAP packets will be explained using Figures 13, 14, 15A, and 15B.

[0215] Figure 13 shows yet another example of the structure of a PLAP packet. In Figure 13, the entire data (payload) structure of a PLAP packet is shown.

[0216] Bits 1301, 1302, 1303, and 1311 are identical to bits 701, 702, 703, and 711 shown in Figure 7, respectively.

[0217] Bits 1312 (Condition_value) and 1313 (Condition) specify the conditions under which the power transmission device 100 will use the PLAP stored in this PLAP packet. An example of the contents of the information stored in bits 1312 and 1313 is shown in Figure 14.

[0218] Bit 1313 is a bit that stores the type of condition. In Figure 14, the content of the condition type 1413 is shown. For example, if bit 1313 is 0, it indicates that the type of condition is the temperature of the power transmission device 100. Also, if bit 1313 is 1, it indicates that the type of condition is the power transmitted by the power transmission device 100. Also, if bit 1313 is 2, it indicates that the type of condition is the coupling coefficient between the power transmission coil 105 of the power transmission device 100 and the power receiving coil 205 of the power receiving device 200. As shown in Figure 14, the conditions are set as the temperature of the power transmission device 100, the power transmitted by the power transmission device 100, and the coupling coefficient between the power transmission coil 105 of the power transmission device 100 and the power receiving coil 205 of the power receiving device 200. If no conditions are set and PLAP are each set as a single constant, the power receiving device 200 selects and stores 3 as the condition. When 3 is selected for the condition, the value stored in bit 1312, described later, is ignored.

[0219] Bit 1312 is a bit that sets the value of Condition selected in bit 1313. Figure 14 shows the contents of the Condition value 1412. If 0 (temperature) is selected for Condition, bit 1312 will store, for example, "value (T [°C]) ÷ 4". If 1 (power transmission) is selected for Condition, bit 1312 will store, for example, "value (P [W]) ÷ 2". If 2 (coupling coefficient) is selected for Condition, bit 1312 will store, for example, "value (k) × 60 - 30". Note that if bit 1312 is, for example, 31, no value will be set regardless of whether 0, 1, or 2 is selected for Condition. Thus, the contents of the value differ depending on the Condition selected in bit 1313.

[0220] In this example, there are no bits to set upper and lower limits for Condition; only one value for Condition is set. Between the set Condition values, the power transmission device 100 performs linear interpolation, as described below.

[0221] The power receiving device 200 uses multiple such PLAP packets to specify the conditions for use and notifies the power transmitting device 100 of the PLAP. The power receiving device 200, for example, uses the four PLAP packets shown in Figure 15A to send a PLAP (α ＦＭ , α ＦＭ，ＤＣ and g ｃｏｉｌ，ＴＸ Let's assume that the power transmission device 100 is notified of the conditions for using each PLAP. Then, as shown in Figure 15B, the power transmission device 100 linearly interpolates the PLAPs between the conditions specified in the PLAP packet (one value of Condition) (e.g., between (88°C, c) and (124°C, a)) using a linear segment of 1500. Note that Figure 15B shows, as an example, α of the PLAPs. ＦＭ This shows that the power transmission device 100 uses each PLAP based on the conditions and linear interpolation shown in Figure 15B to detect foreign objects. Based on the contents shown in Figures 13 and 14, the PLAP packet in sequence "1" shown in Figure 15A corresponds to Packet 1 shown in Figure 15B. Similarly, the PLAP packet in sequence "2" shown in Figure 15A corresponds to Packet 2 shown in Figure 15B. Also, the PLAP packet in sequence "3" shown in Figure 15A corresponds to Packet 3 shown in Figure 15B. Furthermore, the PLAP packet in sequence "4" shown in Figure 15A corresponds to Packet 4 shown in Figure 15B. In this way, the power receiving device 200 transmits a PLAP packet to the power transmission device 100 for each of the multiple temperatures indicated by the multiple conditions, thereby transmitting a separate PLAP to the power transmission device 100 for each of the multiple temperatures indicated by the multiple conditions. As a result, the power transmission device 100 can perform foreign object detection using a separate PLAP for each of the multiple temperatures. Furthermore, the power transmission device 100 can perform foreign object detection using a separate PLAP for each of the temperatures between the multiple temperatures indicated by the multiple conditions by linear interpolation.

[0222] Instead of using linear interpolation as described above, more generally, if n values ​​are provided, an n-1th order interpolation formula may be used to interpolate between the set Condition values.

[0223] Furthermore, even when transmission power or coupling coefficients are specified as conditions, the receiving device 200 transmits individual PLAPs to the transmission device 100 for each of the multiple transmission powers or coupling coefficients indicated by the multiple conditions. This allows the transmission device 100 to perform foreign object detection using individual PLAPs for each of the multiple transmission powers or coupling coefficients. In addition, the transmission device 100 can perform foreign object detection using individual PLAPs for each of the multiple transmission powers or coupling coefficients between the multiple transmission powers or coupling coefficients indicated by the multiple conditions by linear interpolation.

[0224] The temperature, power transmission, and coupling coefficient described above are examples of the state relating to this disclosure and may be referred to as environmental state, environmental conditions, etc. The state (environmental state, environmental conditions) can be said to be the state (condition) relating to the temperature, power transmission, and / or coupling state index of the power transmission device 100 and / or power receiving device 200.

[0225] Returning to the explanation of Figure 5, in S506, the receiving device 200 notifies the transmitting device 100 of its PLAP using one packet, and then proceeds to S507. In S507, the receiving device 200 determines whether or not it has notified the transmitting device 100 of all PLAPs. If not all PLAPs have been notified (No in S507), the receiving device 200 returns to S506 and notifies the transmitting device 100 of the unnotified PLAPs using another PLAP packet. If all PLAPs have been notified (Yes in S507), the receiving device 200 negotiates with the transmitting device 100 regarding the power transmission (GP) in S508. The receiving device 200 transmits the requested power value to the transmitting device 100, and the GP value is determined with the transmitting device 100. GP is an example of power information indicating the power that the receiving device requests from the transmitting device. When the power receiving device 200 notifies the power transmitting device of the requested power value, it can use, for example, a Qi standard Specific Request [Power Level] packet. When the power transmitting device 100 approves the requested power notified by the power receiving device 200, it sends an ACK packet (hereinafter also simply referred to as ACK) to the power receiving device 200.

[0226] Returning to the explanation of Figure 4, when the power receiving device 200 transmits information on the received power value, it starts receiving power in S404 through communication in the Power Transfer phase as defined by the Qi standard. Subsequently, when full charge is reached, the power receiving device 200 transmits an End Power Transfer (EPT) packet of the Qi standard. This stops the power transmission from the power transmitting device 100, and the series of processes for wireless charging are completed.

[0227] [Overall System Processing] Figure 6 is a sequence diagram showing an example of the overall processing of a wireless charging system. In this example sequence diagram, the initial state is assumed to be when the power receiving device 200 is not mounted on the power transmitting device 100 (a state in which power cannot be received), and at F601, the power receiving device 200 is mounted on the power transmitting device 100.

[0228] In F601, the power receiving device 200 is placed on the power transmitting device 100. In F602, the power transmitting device 100 and the power receiving device 200 perform Qi standard Ping phase communication, and the power transmitting device 100 detects that the power receiving device 200 has been placed on it (F603). Also, in F604, the power receiving device 200 detects that it has been placed on the power transmitting device 100.

[0229] The power receiving device 200 transmits identification information and capability information to the power transmitting device 100 via the Configuration phase communication of the Qi standard (not shown). In the Configuration phase, at F605, the power receiving device 200 notifies the power transmitting device 100 of the Qi standard power profile information supported by the power receiving device 200. At F606, the power transmitting device 100 determines the power profile to use based on the Qi standard power profile information supported by the power receiving device 200 and the Qi standard power profile information supported by the power transmitting device 100. Here, the power transmitting device 100 decides to use MPP as the power profile. At F607, the power receiving device 200 requests the power transmitting device 100 for information on the power profile to be used. This request can be made by sending a General Request data package to the power transmitting device 100. In F608, the power transmission device 100 responds to a request from the power receiving device 200 for information on the power profile to be used and notifies the power receiving device 200 of the power profile it has decided to use. Notifying the power profile it has decided to use can be achieved by transmitting a Power Transmitter Identification data package (TX ID Package) from the power transmission device 100 to the power receiving device 200.

[0230] Next, in F609, the power receiving device 200 notifies the power transmitting device 100 of capacity information via communication in the Negotiation phase of the Qi standard. For example, the Extended Power Receiver Capabilities packet of the Qi standard can be used to notify the capacity information. Here, the capacity information of the power receiving device 200 is the minimum required power value, etc. Upon receiving the capacity information from the power receiving device 200, the power transmitting device 100 sends an ACK packet to the power receiving device 200 (F610).

[0231] Next, in F611, the power receiving device 200 requests capability information from the power transmitting device 100. For example, a Get Request [ECAP] packet can be used to request capability information.

[0232] In F612, the power receiving device 200 receives capability information of the power transmitting device 100, which is transmitted from the power transmitting device 100 in response to a request from the power receiving device 200. The power transmitting device 100 notifies the capability information, for example, using an Extended Power Transmitter Extended Capabilities packet. Here, the capability information of the power transmitting device 100 includes the maximum power that can be transmitted, the range of power that can be transmitted, etc.

[0233] In F613, the power receiving device 200 requests a PLAP (Planning and Application of Information) from the power transmitting device 100. For example, a Get Request [PLAP] packet can be used to request the PLAP.

[0234] In F614, the power receiving device 200 receives the PLAP of the power transmitting device 100, which is transmitted from the power transmitting device 100 in response to a request from the power receiving device 200. For example, a PLAP packet can be used to transmit the PLAP.

[0235] In step F615, the power receiving device 200 notifies the power transmitting device 100 of its PLAP. For example, a PLAP packet can be used to notify the PLAP. When the power transmitting device 100 receives a PLAP packet from the power receiving device 200, it sends an ACK packet (F616). If the power receiving device 200 has another PLAP to notify the power transmitting device 100, the power receiving device 200 sends a PLAP packet to the power transmitting device 100. The power receiving device 200 is to receive an ACK packet from the power transmitting device 100 after sending one PLAP packet.

[0236] The receiving device 200 transmits the last PLAP packet to the transmitting device 100 (F617), and upon receiving an ACK packet from the transmitting device 100 (F618), it negotiates with the transmitting device 100 regarding the power to be transmitted in F619. When the negotiation regarding the power to be transmitted is terminated, the receiving device 200 notifies the transmitting device 100 of the termination of the negotiation (F620). For example, the Qi standard Specific Request [End negotiation] packet can be used to notify the termination of the negotiation. Upon receiving the Specific Request [End negotiation] packet from the receiving device 200, the transmitting device 100 transmits an ACK packet to the receiving device 200 in F621.

[0237] Next, at F622, the power transmission device 100 and the power receiving device 200 proceed to the Power Transfer phase and begin the power transmission and reception process. When the battery is fully charged, at F623, the power receiving device 200 sends an End Power Transfer data package (EPT Package) to the power transmission device 100 requesting that power transmission be stopped. Upon receiving the EPT Package, the power transmission device 100 stops transmitting power.

[0238] According to the embodiment described above, the power receiving device 200 notifies the power transmitting device 100 of a PLAP corresponding to one of the conditions among the conditions of the power transmitting device 100 and / or the power receiving device 200, such as temperature, power transmission, and coupling coefficient. The power transmitting device 100 can then select and use these PLAPs according to the conditions and perform foreign object detection processing. In other words, the power transmitting device 100 can select and use appropriate correction values ​​according to the environment, perform foreign object detection appropriately, and perform wireless power transmission appropriately.

[0239] <Second Embodiment> In the first embodiment, an example was described in which there is one type of PLAP condition notified from the power receiving device 200 to the power transmitting device 100. In this embodiment, an example is described in which there are multiple types of PLAP conditions notified from the power receiving device 200 to the power transmitting device 100. Note that redundant explanations will be omitted for configurations and processes that are the same as or similar to those in the first embodiment.

[0240] The configuration examples of the wireless charging system, power transmission device, and power receiving device in this embodiment, as well as the method for detecting foreign objects during wireless power transmission, are the same as in the first embodiment, so their explanation will be omitted.

[0241] [Processing of the Power Receiving Device] In this embodiment, as in the first embodiment, an example of processing of wireless power transmission based on the Qi standard by the power receiving device 200 will be explained using the flowchart shown in Figure 4. In this embodiment, an example using MPP as the power profile is shown. This processing can be realized, for example, by the control unit 201 of the power receiving device 200 executing a program read from the memory 208. At least a part of the following procedure may be realized by hardware. In this case, the hardware can be realized, for example, by automatically generating a dedicated circuit using a gate array circuit such as an FPGA from a program to realize each processing step using a predetermined compiler.

[0242] The processing specified in the Ping phase of the Qi standard in S401 and the processing specified in the Configuration phase of the Qi standard in S402 are the same as in the first embodiment.

[0243] In S403, the power receiving device 200 initiates communication in the Negotiation phase as defined by the Qi standard. During the Negotiation phase, PLAP information is sent and received between the power transmitting device 100 and the power receiving device 200, and negotiations regarding the transmitted power take place.

[0244] In this embodiment, as in the first embodiment, the details of the processing example in the Negotiation phase by the power receiving device 200 will be explained using the flowchart shown in Figure 5.

[0245] The process from S501 to S505 is the same as in the first embodiment.

[0246] In S506, the power receiving device 200 notifies the power transmitting device 100 of the PLAP of the power receiving device 200. Here, the power receiving device 200 stores the information (PLAP) in a single packet and notifies it. For example, a PLAP packet can be used to notify the PLAP.

[0247] Here, an example of a PLAP packet transmitted by the power receiving device 200 to the power transmitting device 100 is shown in Figure 16. In Figure 16, the entire data (payload) structure of the PLAP packet is shown.

[0248] Bits 1601 (Alpha_FM), 1602 (Alpha_FM_DC), and 1603 (g_coil_TX) are the α described in the MPLA explanation, respectively. ＦＭ , α ＦＭ，ＤＣ and g ｃｏｉｌ，ＴＸ This is the bit that stores the value of α. ＦＭ , α ＦＭ，ＤＣ and g ｃｏｉｌ，ＴＸ This is the PLAP of the power receiving device 200.

[0249] Bit 1611 (More) indicates whether there are any other PLAP packets (PLAPs) to be notified besides this packet. For example, if bit 1611 is 1, it indicates that there are any other PLAP packets to be notified besides this packet, and if it is 0, it indicates that there are no other PLAP packets to be notified besides this packet. The meanings of "1" and "0" may be reversed.

[0250] Bits 1612 (Condition_P), 1613 (Condition_k), and 1614 (Condition_T) specify the conditions under which the power transmission device 100 will use the PLAP stored in this PLAP packet. As described above, PLAP is α ＦＭ , α ＦＭ，ＤＣ and g ｃｏｉｌ，ＴＸ Figure 17 shows an example of the information stored in bits 1612, 1613, and 1614.

[0251] Below, an example of the structure of a PLAP packet according to this embodiment will be described using Figures 16 and 17.

[0252] Bit 1614 is a bit that specifies the type of the first condition. Here, an example is shown where the type of the first condition is the temperature of the power transmission device 100. Figure 17 shows the content of the temperature condition 1714. For example, if bit 1614 is 0, it indicates that the temperature condition is 50°C or less; if it is 1, it indicates that the temperature condition is greater than 50°C and 90°C or less; and if it is 2, it indicates that the temperature condition is greater than 90°C. Note that if 3 is selected for bit 1614, it means that no temperature condition is specified.

[0253] Bit 1613 specifies the type of the second condition. Here, we show an example where the type of the second condition is the coupling coefficient between the power transmission coil 105 of the power transmission device 100 and the power receiving coil 205 of the power receiving device 200. Figure 17 shows the content of the coupling coefficient condition 1713. For example, if bit 1613 is 0, it indicates that the coupling coefficient condition is 0.8 or less; if it is 1, it indicates that the coupling coefficient condition is greater than 0.8 and 0.9 or less; and if it is 2, it indicates that the coupling coefficient condition is greater than 0.9. Note that if 3 is selected for bit 1613, it means that no coupling coefficient condition is specified.

[0254] Bit 1612 is a bit that specifies the type of the third condition. Here, an example is shown where the type of the third condition is the power transmitted by the power transmission device 100. Figure 17 shows the content of the power transmission condition 1712. For example, if bit 1612 is 0, it indicates that the power transmission condition is 25W or less; if it is 1, it indicates that the power transmission condition is greater than 25W and 50W or less; and if it is 2, it indicates that the power transmission condition is greater than 50W. Note that if 3 is selected for bit 1612, it means that no power transmission condition is specified.

[0255] The power receiving device 200 uses multiple such PLAP packets to specify the conditions for use and notifies the power transmitting device 100 of the PLAP. The power receiving device 200, for example, uses the nine PLAP packets shown in Figure 18A to send a PLAP (α ＦＭ , α ＦＭ，ＤＣ and g ｃｏｉｌ，ＴＸ Let's assume that the power transmission device 100 is notified of the conditions for using each PLAP. Then, the power transmission device 100 uses each PLAP under the conditions shown in Figure 18B to detect foreign objects. Figure 18B shows, as an example, α of the PLAPs. ＦＭ This shows that, based on the contents shown in Figures 16 and 17, the PLAP packet in order "1" shown in Figure 18A and the α with the temperature condition "50°C or less" and the coupling coefficient condition "less than 0.8" shown in Figure 18B ＦＭAnd correspond. Similarly, the PLAP packet in order "5" shown in Figure 18A and the α with the temperature condition "greater than 50°C and less than 90°C" and the coupling coefficient condition "0.8 or more and less than 0.9" shown in Figure 18B ＦＭ For example, the two conditions correspond to each other. The power receiving device 200 sends PLAP packets to the power transmitting device 100 for each of the multiple temperature range-coupling coefficient range combinations indicated by the multiple conditions. In this way, the power receiving device 200 sends a separate PLAP to the power transmitting device 100 for each of the multiple temperature range-coupling coefficient range combinations indicated by the multiple conditions. As a result, the power transmitting device 100 can perform foreign object detection using a separate PLAP for each of the multiple temperature range-coupling coefficient range combinations.

[0256] Furthermore, if any two or more combinations of the temperature range, power transmission range, and coupling coefficient range are specified as conditions, the power receiving device 200 also transmits a separate PLAP to the power transmitting device 100 for each of the multiple combinations indicated by the multiple conditions. This allows the power transmitting device 100 to perform foreign object detection using a separate PLAP for each of the multiple combinations.

[0257] Any two or more combinations of the temperature range, power transmission range, and coupling coefficient range described above are examples of states relating to this disclosure and may be referred to as environmental states, environmental conditions, etc. A state (environmental state, environmental conditions) can be said to be a state (condition) relating to the temperature, power transmission, and / or coupling state index of the power transmission device 100 and / or power receiving device 200.

[0258] Returning to the explanation of Figure 5, in S506, the power receiving device 200 notifies the power transmitting device 100 of its PLAP using one packet, and then proceeds to S507. In S507, the power receiving device 200 determines whether or not it has notified the power transmitting device 100 of all PLAPs. If not all PLAPs have been notified (No in S507), the power receiving device 200 returns to S506 and notifies the power transmitting device 100 of the unnotified PLAPs using separate PLAP packets. If all PLAPs have been notified (Yes in S507), the power receiving device 200 negotiates with the power transmitting device 100 regarding the power transmission (GP) in S508. The processing in S508 is the same as in the first embodiment, so the explanation is omitted.

[0259] Returning to the explanation of Figure 4, when the power receiving device 200 transmits information on the received power value, it starts receiving power in S404 through communication in the Power Transfer phase as defined by the Qi standard. Subsequently, when full charge is reached, the power receiving device 200 transmits an End Power Transfer (EPT) packet of the Qi standard. This stops the power transmission from the power transmitting device 100, and the series of processes for wireless charging are completed.

[0260] The overall processing of the wireless charging system is the same as in the first embodiment, so a description will be omitted.

[0261] According to the embodiment described above, the power receiving device 200 notifies the power transmitting device 100 of PLAPs corresponding to multiple types of conditions such as the temperature of the power transmitting device 100 and / or the power receiving device 200, the power transmitted, and the coupling coefficient conditions. The power transmitting device 100 can then select and use these PLAPs according to the conditions and perform the foreign object detection process. In other words, the power transmitting device 100 can select and use appropriate correction values ​​according to the environment, perform foreign object detection appropriately, and perform wireless power transmission appropriately.

[0262] <Third Embodiment> In the first and second embodiments, an example was described in which a PLAP corresponding to one or more types of conditions is notified from the power receiving device 200 to the power transmitting device 100. In this embodiment, an example is described in which a PLAP corresponding to one or more types of conditions is notified from the power receiving device 200 to the power transmitting device 100 when power is transmitted from the power transmitting device 100 to the power receiving device 200 using the rapid charging mode. Note that redundant explanations will be omitted for configurations and processes that are the same as or similar to those in the first or second embodiment.

[0263] The configuration examples of the wireless charging system, power transmission device, and power receiving device in this embodiment, as well as the method for detecting foreign objects during wireless power transmission, are the same as in the first embodiment, so their explanation will be omitted.

[0264] [Processing of the Power Receiving Device] In this embodiment, as in the first embodiment, an example of wireless power transmission processing based on the Qi standard by the power receiving device 200 will be explained using the flowchart shown in Figure 4 and the sequence diagram shown in Figure 20. In this embodiment, an example using MPP as the power profile will be shown. This processing can be realized, for example, by the control unit 201 of the power receiving device 200 executing a program read from the memory 208. At least a part of the following procedure may be realized by hardware. In this case, the hardware can be realized, for example, by automatically generating a dedicated circuit using a gate array circuit such as an FPGA from a program to realize each processing step using a predetermined compiler.

[0265] The processing specified in the Ping phase of the Qi standard S401 (F2001 to F2004) and the processing specified in the Configuration phase of the Qi standard S402 (F2005 to F2008) are the same as in the first embodiment.

[0266] In S403, the power receiving device 200 initiates communication in the Negotiation phase as defined by the Qi standard. Furthermore, in S404, the power receiving device 200 begins receiving power through communication in the Power Transfer phase as defined by the Qi standard (F2030). Subsequently, when full charge is reached, the power receiving device 200 transmits an End Power Transfer (EPT) packet according to the Qi standard (F2032). This stops power transmission from the power transmitting device 100, and the series of processes for wireless charging are completed.

[0267] Figure 19 shows detailed examples of processing in the Negotiation phase and Power Transfer phase. Hereinafter, details of processing examples in the Negotiation phase and Power Transfer phase by the power receiving device 200 in this embodiment will be explained using Figures 19 and 20.

[0268] First, in S1901 (F2009), the power receiving device 200 notifies the power transmitting device 100 of its capabilities. For notifying the capabilities, for example, the Extended Power Receiver Capabilities packet of the Qi standard can be used. The capabilities information of the power receiving device 200 to be notified includes information indicating that the power receiving device 200 supports the fast charging mode. Here, "supporting the fast charging mode" means that the power transmitting device 100 or the power receiving device 200 has hardware, control means and functions that enable it to operate in the fast charging mode. This packet is provided with a 1-bit field indicating whether or not it supports the fast charging mode. If the power receiving device 200 notifies the power transmitting device 100 that it supports the fast charging mode, it stores "1" in the field, and if it notifies the power transmitting device 100 that it does not support the fast charging mode, it stores "0" in the field. Note that the meanings of "1" and "0" stored in the field may be reversed. This packet also includes the minimum required power value. Upon receiving the capacity information of the power receiving device 200 from the power receiving device 200, the power transmitting device 100 sends an acknowledgment (ACK) to the power receiving device 200 (F2010).

[0269] Next, in S1902 (F2011), the power receiving device 200 requests capability information from the power transmitting device 100. For example, a Get Request [ECAP] packet can be used to request capability information. Upon receiving the capability information request from the power receiving device 200, the power transmitting device 100 notifies the power receiving device 200 of its capability information (F2012). The power transmitting device 100 makes this notification, for example, using an Extended Power Transmitter Extended Capabilities packet. Here, the capability information of the power transmitting device 100 includes information indicating that it supports the rapid charging mode. When the power transmitting device 100 notifies the power receiving device 200 that it supports the rapid charging mode, it stores "1" in the corresponding field, and when it notifies the power transmitting device 100 that it does not support the rapid charging mode, it stores "0" in the corresponding field. Note that the meanings of "1" and "0" stored in the relevant field may be reversed. This packet also includes information such as the maximum power that can be transmitted and the range of power that can be transmitted.

[0270] In S1904, the power receiving device 200 determines whether it has received a packet from the power transmitting device 100 containing information indicating that it supports the rapid charging mode. If it does not receive a packet, the power receiving device 200 periodically or irregularly makes the determination in S1904 until a predetermined time has elapsed (No in S1904, No in S1918). If the power receiving device 200 does not receive a packet containing information indicating that the power transmitting device 100 supports the rapid charging mode within the predetermined time (No in S1904, Yes in S1918), it terminates the process. That is, the power receiving device 200 returns to the Ping phase.

[0271] The above example shows a scenario in which the power receiving device 200 transmits information to the power transmitting device 100 stating that "the power receiving device 200 supports rapid charging mode," then requests capability information, and receives information that "the power transmitting device 100 supports rapid charging mode." However, the order of information transmission and reception may be reversed. In other words, the power receiving device 200 may receive information from the power transmitting device 100 stating that "the power transmitting device 100 supports rapid charging mode," and then transmit the same information to the power transmitting device 100.

[0272] Furthermore, the information that "the power receiving device 200 supports rapid charging mode" may be transmitted before the Configuration phase. This information may be stored in the Signal Strength data packet transmitted from the power receiving device 200 to the power transmitting device 100 during the Ping phase. Alternatively, this information may be stored in a packet transmitted during the Configuration phase. As the packet in which this information is stored, an Identification data packet, an Extended Identification data packet, a Configuration data packet, etc., can be used.

[0273] Next, the power receiving device 200 transmits a packet to the power transmitting device 100 containing "information for determining whether or not the conditions for transitioning to rapid charging mode are met" (S1905, F2013). For example, the Qi standard Extended Power Receiver Capabilities packet can be used as this packet. Note that the Extended Power Receiver Capabilities packet transmitted in S1901 and S1905 may be the same single packet. In this case, S1901 and S1905 are performed in a single process (S1901). Note that any packet used in the Negotiation phase may be used instead of the Extended Power Receiver Capabilities packet.

[0274] Here, we will explain the conditions under which rapid charging mode can be activated. These conditions may include all of the following conditions, a combination of some of them, or just one of them.

[0275] (First condition) The first condition is that the power transmission device 100 and the power receiving device 200 are compatible with MPP. MPP has the function of fixing the power transmission device 100 and the power receiving device 200 in predetermined positions with high precision. When transmitting a large amount of power in rapid charging mode, it is desirable for the environment to increase the power transmission efficiency and reduce power loss. Therefore, if the power transmission device 100 and the power receiving device 200 are compatible with MPP and capable of operating in MPP mode, the power transmission device 100 and the power receiving device 200 are controlled to operate in rapid charging mode.

[0276] Furthermore, the information that the power receiving device 200 is compatible with MPP has already been notified to the power transmission device 100 during the Configuration phase. Therefore, this information does not need to be notified in S1905.

[0277] (Second Condition) The second condition is that the coupling state index between the transmitting antenna (transmitting coil) of the power transmission device 100 and the receiving antenna (receiving coil) of the power receiving device 200 is equal to or exceeds a predetermined value. Here, the coupling state index is the coupling coefficient between the transmitting coil 105 of the power transmission device 100 and the receiving coil 205 of the power receiving device 200, as measured by the power transmission device 100 or the power receiving device 200. The method for measuring the coupling state index is as described in the "Method for Measuring the Coupling State Index Between the Transmitting Antenna and the Receiving Antenna" above. If the transmitting antenna of the power transmission device 100 and the receiving antenna of the power receiving device 200 are facing each other, the value of the coupling state index will also be a good value (a large value in the case of the coupling coefficient), the power transmission efficiency will be high, and this is preferable. Therefore, if the measured coupling state index between the power transmission device 100 and the power receiving device 200 is equal to or exceeds a set threshold, the power transmission device 100 and the power receiving device 200 are controlled to operate in rapid charging mode.

[0278] Furthermore, the parameters necessary for the power transmission device 100 to measure the coupling state index between the power transmission coil 105 of the power transmission device 100 and the power receiving coil 205 of the power receiving device 200 have already been notified to the power transmission device 100 in the Configuration phase. Therefore, these parameters do not need to be notified in S1905.

[0279] (Third Condition) The third condition is that the temperature of a predetermined location on the power transmission device 100 and / or the power receiving device 200 is below or equal to a predetermined value. When transmitting high power in rapid charging mode, the components of the power transmission device 100 or the power receiving device 200 (transmission antenna, receiving antenna, battery, etc.) generate more heat than when transmitting low power. Therefore, if the power transmission device 100 or the power receiving device 200 is at a high temperature when the system switches to rapid charging mode and transmits high power, it may lead to the destruction of the power transmission device 100 or the power receiving device 200. Therefore, when the temperature of the power transmission device 100 and / or the power receiving device 200 is below or equal to a predetermined value, the power transmission device 100 and the power receiving device 200 are controlled to operate in rapid charging mode.

[0280] Here, a control method based on the temperature of the power transmission device 100 will be described. The power transmission device 100 and the power receiving device 200 each have temperature sensors at multiple locations. In particular, the power transmission antenna 105 and the charging base 300, and the power receiving antenna 205, have a higher density of temperature sensors compared to other locations.

[0281] In S1905, the power receiving device 200 transmits a packet to the power transmitting device 100 that includes "timing information indicating when the power transmitting device 100 acquires temperature information from the temperature sensor of the power transmitting device 100". This information may also include information used to determine the temperature threshold to be set.

[0282] (Fourth condition) The fourth condition is that the power transmission device 100 and the power receiving device 200 are operating in MPP mode as described above. The power transmission device 100 and the power receiving device 200 operate in MPP mode by performing predetermined control. When the power transmission device 100 and the power receiving device 200 are operating in MPP mode, they determine that "the conditions for transitioning to rapid charging mode are met" and control them to operate in rapid charging mode.

[0283] The above explanation uses the first to fourth conditions as examples to describe the "conditions for switching to fast charging mode." Note that the "conditions for switching to fast charging mode" may also be a combination of any two or more of the first to fourth conditions described above. For example, the condition where both the first and second conditions are met may be considered the "condition for switching to fast charging mode." Furthermore, the condition may be not only a combination of two of the first to fourth conditions, but also a combination of three or all of them, and the condition where all of these conditions are met may be considered the "condition for switching to fast charging mode."

[0284] When the power transmission device 100 receives a packet containing "information for determining whether or not the conditions for transitioning to rapid charging mode are met," it determines whether or not the conditions for transitioning to rapid charging mode are met based on that information (F2014). If it is determined that "the conditions for transitioning to rapid charging mode are met" (Yes in F2014), the power transmission device 100 sends a packet to the power receiving device 200 containing information indicating that "the conditions for transitioning to rapid charging mode are met" (F2015). The packet used is an acknowledgment (ACK).

[0285] The power receiving device 200 determines whether it has received a packet from the power transmitting device 100 containing information indicating that the conditions for transitioning to rapid charging mode have been met (S1906). If the power receiving device 200 has not received the packet from the power transmitting device 100 (for example, if it receives a negative response, NAK), it performs the determination in S1906 periodically or irregularly until a predetermined period has elapsed (No in S1906, No in S1919). If the power receiving device 200 does not receive a packet containing information indicating that the conditions for transitioning to rapid charging mode have been met within a predetermined time (No in S1906, Yes in S1919), it terminates the process. In other words, the power receiving device 200 returns to the Ping phase.

[0286] When the power receiving device 200 receives the packet from the power transmitting device 100 (Yes in S1906), it sends a packet to the power transmitting device 100 containing information indicating a request to switch to rapid charging mode (S1907, F2016). For this request (transmission), for example, a Qi standard Specific Request packet can be used. This packet has a 1-bit field indicating whether or not to request a switch to rapid charging mode. If the power receiving device 200 requests the power transmitting device 100 to switch to rapid charging mode, it stores "1" in the field; if it does not request a switch to rapid charging mode, it stores "0" in the field. Note that the meanings of "1" and "0" stored in the field may be reversed. In addition, any packet used in the Negotiation phase may be used instead of the Specific Request packet.

[0287] When the power transmission device 100 receives a packet from the power receiving device 200 containing information indicating a request to switch to rapid charging mode, it sends an acknowledgment (ACK) to the power receiving device 200 (F2017). The power receiving device 200 determines whether or not it has received an ACK from the power transmission device 100 (S1908). If the power receiving device 200 does not receive an ACK from the power transmission device 100, it periodically or irregularly makes the determination in S1908 until a predetermined time has elapsed (No in S1908, No in S1920). If the power receiving device 200 has not received an ACK even after the predetermined time has elapsed (No in S1908, Yes in S1920), it terminates the process. That is, the power receiving device 200 returns to the Ping phase. If the power receiving device 200 has received an ACK from the power transmission device 100 (Yes in S1908), it proceeds to S1909.

[0288] The processing from S1909 to S1912 (F2018 to F2023) is the same as S504 to S507 in Figure 5 (F613 to F618 in Figure 6) described in the first embodiment, so the explanation is omitted.

[0289] In S1913 (F2024), the receiving device 200 negotiates the power transmission (GP) with the transmitting device 100. The receiving device 200 transmits the requested power value to the transmitting device 100, and the GP value is determined with the transmitting device 100. GP is an example of power information indicating the power that the receiving device requests from the transmitting device. When the receiving device 200 notifies the transmitting device 100 of the requested power value, it can use, for example, the Qi standard Specific Request [Power Level] packet. If the transmitting device 100 approves the requested power notified by the receiving device 200, it sends an ACK to the receiving device 200. Here, the receiving device 200 can set the requested power to the transmitting device 100 to more than 15 watts or 15 watts or more.

[0290] When negotiating the end of power transmission, the receiving device 200 notifies the transmission device 100 of the termination of negotiations (F2025). For example, the Qi standard Specific Request [End negotiation] packet can be used to notify the termination of negotiations. When the transmission device 100 receives the Specific Request [End negotiation] packet sent from the receiving device 200, it sends an ACK packet to the receiving device 200 in F2026.

[0291] Next, in S1914 (F2027), the power receiving device 200 begins receiving low-power power of less than 5 watts or 5 watts or less from the power transmitting device 100. Then, in S1915 (F2028), the power receiving device 200 performs authentication. Here, authentication is the process by which the power receiving device 200 authenticates the power transmitting device 100. Authentication includes the process by which the power receiving device 200 determines whether or not the power transmitting device 100 is compatible with authentication.

[0292] If the power receiving device 200 determines that the power transmitting device 100 is compatible with authentication, it transmits a predetermined first packet to the power transmitting device 100. The power receiving device 200 determines whether the response from the power transmitting device 100 that received the predetermined first packet satisfies predetermined conditions. If the power receiving device 200 determines that the predetermined conditions are met, it transmits a predetermined second packet to the power transmitting device 100. Based on the content of the response from the power transmitting device 100 that received the predetermined second packet, the power receiving device 200 determines whether authentication was successful (F2029).

[0293] Alternatively, in the authentication process, in addition to the process in which the power receiving device 200 authenticates the power transmitting device 100, the power transmitting device 100 may also perform a process in which it authenticates the power receiving device 200. Authentication includes a process in which the power transmitting device 100 determines whether or not the power receiving device 200 is compatible with authentication. If the power transmitting device 100 determines that the power receiving device 200 is compatible with authentication, it transmits a predetermined third packet to the power receiving device 200. The power transmitting device 100 determines whether or not the response from the power receiving device 200 that received the predetermined third packet satisfies predetermined conditions. If the power transmitting device 100 determines that the predetermined conditions are met, it transmits a predetermined fourth packet to the power receiving device 200. The power transmitting device 100 determines whether or not authentication was successful based on the content of the response from the power receiving device 200 that received the predetermined fourth packet. In this case, the power transmission device 100 and the power receiving device 200 determine that "authentication is successful" when the power receiving device 200 determines that the authentication of the power transmission device 100 is successful, and the power transmission device 100 determines that the authentication of the power receiving device 200 is successful (F2029).

[0294] If authentication is successful (Yes in S1915), the power receiving device 200 executes control for operation in rapid charging mode (S1916, F2030). Successful authentication allows the power receiving device 200 to receive power from the reliable power transmitting device 100. Therefore, when the power receiving device 200 attempts to receive high power in rapid charging mode from the power transmitting device 100, it controls itself to switch to rapid charging mode only when authentication is successful. Rapid charging mode enables power transmission up to GP determined in S1913. Here, the control during operation in rapid charging mode is control to solve problems that occur during operation in rapid charging mode. Such control is, for example, control to prevent noise leakage into the surroundings, communication instability, deterioration of foreign object detection accuracy, etc.

[0295] Next, in S1917 (S2031), the power receiving device 200 starts receiving power in rapid charging mode.

[0296] On the other hand, if authentication fails (No in S1915), in S1921, the receiving device 200 negotiates with the transmitting device 100 again regarding the power transmission (GP). The receiving device 200 transmits the requested power value to the transmitting device 100, and the GP value is determined with the transmitting device 100. Here, the receiving device 200 sets the requested power to the transmitting device 100 to 5 watts or less. When the receiving device 200 notifies the transmitting device of the requested power value, for example, the Qi standard Specific Request [Power Level] packet can be used. If the transmitting device 100 approves the requested power notified by the receiving device 200, it sends an ACK to the receiving device 200. Next, in S1922, the receiving device 200 starts receiving power at low power.

[0297] In this embodiment, when the conditions for receiving power from the power receiving device 200 are met, the power receiving device 200 notifies the power transmitting device 100 of PLAP. Here, the conditions for receiving power from the power receiving device 200 are met, for example, when the MPP rapid charging mode specified in the Qi standard is applied to the power receiving of the power receiving device 200, as described above. Alternatively, the conditions for receiving power from the power receiving device 200 may also be met, for example, when the power received by the power receiving device 200 is greater than 15 watts or 15 watts or more.

[0298] According to the embodiment described above, when transmitting power from the power transmission device 100 to the power receiving device 200 using the rapid charging mode, the power receiving device 200 notifies the power transmission device 100 of one or more types of conditions. Here, the one or more types of conditions are one or more of the conditions of the power transmission device 100 and / or the power receiving device 200, such as temperature, transmitted power, and coupling coefficient. The power transmission device 100 can then select and use these PLAPs according to the conditions and perform foreign object detection processing. In other words, only when using the rapid charging mode, the power transmission device 100 can select and use appropriate correction values ​​according to the environment, perform foreign object detection appropriately, and perform wireless power transmission appropriately.

[0299] <Other Embodiments> In the embodiments described above, an example was shown in which the power receiving device 200 notifies the power transmission device 100 of the PLAP of the power receiving device 200 before the negotiation of the power transmission power between the power receiving device 200 and the power transmission device 100. However, this disclosure is not limited thereto, and the order may be reversed. That is, the power receiving device 200 may notify the power transmission device 100 of the PLAP of the power receiving device 200 after the negotiation of the power transmission power between the power receiving device 200 and the power transmission device 100. In this case, since the power transmission power of the power transmission device 100 has been determined, the power receiving device 200 may narrow down the conditions of the PLAP to be notified to the power transmission device 100 according to the determined power transmission power.

[0300] Furthermore, in each of the embodiments described above, an example was shown in which the power receiving device 200 notifies the power transmitting device 100 of the PLAP of the power receiving device 200 during the Negotiation phase. However, this disclosure is not limited thereto. The power receiving device 200 may notify the power transmitting device 100 of the PLAP, for example, during the Configuration phase.

[0301] In this case, the packets used include Identification data packets (ID packets), Extended Identification data packets (XID packets), Configuration data packets, etc.

[0302] Furthermore, in each of the embodiments described above, the PLAP that the power receiving device 200 notifies the power transmitting device 100 is α as shown in "Method for detecting foreign objects during wireless power transmission". ＦＭ , α ＦＭ，ＤＣ and g ｃｏｉｌ，ＴＸ However, this disclosure is not limited to this. For example, the types of PLAP may be increased.

[0303] In the "Method for detecting foreign objects during wireless power transmission," an example of calculating friendly metal loss using (Equation 5) was shown. This equation approximates the friendly metal loss graph with a linear function. However, this disclosure is not limited to a linear function. For example, the friendly metal loss graph may be approximated with a quadratic function by increasing the number of terms. In this case, the friendly metal loss can be calculated using (Equation 12) below.

[0304]

[0305] In this case, the power receiving device 200 is a parameter related to the power receiving device 200, α ＦＭ２ This is notified to the power transmission device 100. For example, the PLAP packet shown in Figure 7 is modified, and as shown in Figure 22, α ＦＭ２ It may be possible to notify the following. If bit 2215 (Type) shown in Figure 22 is 0, the information of bits 2201 to 2203 is the same as bits 701 to 703 shown in Figure 7. On the other hand, if bit 2215 (Type) is 1, the power receiving device 200 will send α to bit 2201. ＦＭ２ This shall store the Reserved bit (B) in the PLAP packet shown in Figure 16. ０ b in ６ Similarly, by changing to the Type mentioned above, α ＦＭ２ It is possible to notify them of this.

[0306] 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.

[0307] Furthermore, for example, the receiving device may possess some or all of the functions of the power transmission device. Alternatively, the receiving device may perform some or all of the processing that the power transmission device would normally perform.

[0308] Furthermore, the configurations in the above-described embodiments may be combined as appropriate.

[0309] 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.

[0310] 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).

[0311] 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, for example, be compatible with the Global Positioning System (Global Positioning Satellite, GPS). The communication unit may also be compatible with communication standards such as the fifth-generation mobile communication system (5G). Furthermore, the vehicle may be a bicycle or a motorcycle.

[0312] Furthermore, the power receiving device in this disclosure may also be a power tool, a home appliance, etc. These devices, which are 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. Furthermore, these devices may 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).

[0313] 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.

[0314] 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.

[0315] 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., ASIC) that implements one or more functions.

[0316] 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.

[0317] Furthermore, the following additional information is disclosed regarding the above embodiments.

[0318] [Note 1] A power receiving device characterized by comprising: a power receiving means for receiving power wirelessly from a power transmission device; and a communication means used for detecting foreign objects, which transmits individual parameters for each of a plurality of states to the power transmission device.

[0319] [Note 2] The power receiving means is characterized in that it can receive power wirelessly from the power transmitting device based on the MPP (Magnetic Power Profile) specified in the standards formulated by the Wireless Power Consortium, as described in Note 1.

[0320] [Note 3] The power receiving device according to Note 1 or 2, characterized in that the parameter is a parameter relating to MPP Power Loss Accounting.

[0321] [Note 4] The power receiving device according to any one of Notes 1 to 3, characterized in that the state is a state relating to the temperature of the power transmitting device and / or the power receiving device, the power transmitted by the power transmitting device, and / or an indicator of the coupling state between the power transmitting coil of the power transmitting device and the power receiving coil of the power receiving device.

[0322] [Note 5] The power receiving device according to any one of Notes 1 to 4, characterized in that the communication means transmits a single packet to the power transmitting device, which includes the value of the parameter and information about the state in which the parameter is used among the plurality of states.

[0323] [Appendix 6] The power receiving device according to Appendix 5, characterized in that the communication means transmits one packet to the power transmitting device for a number of times equal to the number of states.

[0324] [Note 7] The power receiving device according to any one of Notes 1 to 6, wherein the communication means transmits the parameters to the power transmitting device when the conditions for receiving power of the power receiving device are met.

[0325] [Note 8] The power receiving device according to Note 7, characterized in that the power received by the power receiving device exceeds 15 watts.

[0326] [Appended Note 9] The power receiving device according to Appended Note 7, wherein the condition is that a rapid charging mode is applied to the power reception of the power receiving device.

[0327] [Appended Note 10] A power transmission device, comprising: a power transmission means for wirelessly transmitting power to a power receiving device; and a communication means for use in foreign object detection, which receives individual parameters for each of a plurality of states from the power receiving device.

[0328] [Appended Note 11] The power transmission device according to Appended Note 10, wherein the power transmission means is capable of wirelessly transmitting power to the power receiving device based on an MPP (Magnetic Power Profile) defined by a standard formulated by the Wireless Power Consortium.

[0329] [Appended Note 12] The power transmission device according to Appended Note 10 or 11, wherein the parameter is a parameter related to MPP Power Loss Accounting.

[0330] [Appended Note 13] The power transmission device according to any one of Appended Notes 10 to 12, wherein the state is a state related to an index of the temperature of the power transmission device and / or the power receiving device, the power transmission power of the power transmission device, and / or the coupling state between a power transmission coil of the power transmission device and a power receiving coil of the power receiving device.

[0331] [Appended Note 14] The power transmission device according to any one of Appended Notes 10 to 13, wherein the communication means receives, from the power receiving device, one packet including a value of the parameter and information related to a state in which the parameter is used among the plurality of states.

[0332] [Appended Note 15] The power transmission device according to Appended Note 14, wherein the communication means receives the one packet from the power receiving device for each number of the plurality of states.

[0333] [Appended Note 16] The power transmission device according to any one of Appended Notes 10 to 15, further comprising a foreign object detection means for performing the foreign object detection using the parameter.

[0334] [Appended Note 17] A method performed by a power receiving device, comprising: a step of wirelessly receiving power from a power transmitting device; and a step of transmitting individual parameters for each of a plurality of states, which are used for foreign object detection, to the power transmitting device.

[0335] [Appended Note 18] A method performed by a power transmitting device, comprising: a step of wirelessly transmitting power to a power receiving device; and a step of receiving individual parameters for each of a plurality of states, which are used for foreign object detection, from the power receiving device.

[0336] [Appended Note 19] A program for causing a computer to execute the method according to Appended Note 17 or 18.

[0337] The present invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, the following claims are appended to disclose the scope of the present invention.

[0338] This application claims priority based on Japanese Patent Application No. 2024-172694 filed on October 1, 2024, and incorporates all of the description therein.

Claims

1. A power receiving device characterized by comprising: a power receiving means for wirelessly receiving power from a power transmission device; and a communication means used for detecting foreign objects, which transmits individual parameters for each of a plurality of states to the power transmission device.

2. The power receiving device according to claim 1, characterized in that the power receiving means is capable of receiving power wirelessly from the power transmitting device based on the MPP (Magnetic Power Profile) specified in the standards formulated by the Wireless Power Consortium.

3. The power receiving device according to claim 2, characterized in that the parameter is a parameter relating to MPP Power Loss Accounting.

4. The power receiving device according to claim 1, characterized in that the state is a state relating to the temperature of the power transmitting device and / or the power receiving device, the power transmitted by the power transmitting device, and / or an indicator of the coupling state between the power transmitting coil of the power transmitting device and the power receiving coil of the power receiving device.

5. The power receiving device according to claim 1, characterized in that the communication means transmits a single packet to the power transmitting device, the packet containing the value of the parameter and information relating to the state in which the parameter is used among the plurality of states.

6. The power receiving device according to claim 5, characterized in that the communication means transmits one packet to the power transmitting device for a number of times equal to the number of states.

7. The power receiving device according to claim 1, characterized in that the communication means transmits the parameters to the power transmitting device when the conditions for receiving power of the power receiving device are met.

8. The power receiving device according to claim 7, characterized in that the condition is that the power received by the power receiving device exceeds 15 watts.

9. The power receiving device according to claim 7, characterized in that the condition is that a rapid charging mode is applied to the power receiving device.

10. A power transmission device characterized by comprising: a power transmission means for wirelessly transmitting power to a power receiving device; and a communication means used for detecting foreign objects, which receives individual parameters for each of a plurality of states from the power receiving device.

11. The power transmission device according to claim 10, characterized in that the power transmission means is capable of wirelessly transmitting power to the power receiving device based on the MPP (Magnetic Power Profile) specified in the standards formulated by the Wireless Power Consortium.

12. The power transmission device according to claim 11, characterized in that the parameter is a parameter relating to MPP Power Loss Accounting.

13. The power transmission device according to claim 10, characterized in that the state is a state relating to the temperature of the power transmission device and / or the power receiving device, the power transmitted by the power transmission device, and / or an indicator of the coupling state between the power transmission coil of the power transmission device and the power receiving coil of the power receiving device.

14. The power transmission device according to claim 10, characterized in that the communication means receives a single packet from the power receiving device, the packet containing the value of the parameter and information relating to the state in which the parameter is used among the plurality of states.

15. The power transmission device according to claim 14, characterized in that the communication means receives one packet from the power receiving device for a number of times equal to the number of states.

16. The power transmission device according to claim 10, further comprising a foreign object detection means for performing the foreign object detection using the parameters.

17. A method performed by a power receiving device, comprising the steps of: receiving power wirelessly from a power transmitting device; and transmitting to the power transmitting device individual parameters for each of a plurality of states, which are used for foreign object detection.

18. A method performed by a power transmission device, comprising the steps of: wirelessly transmitting power to a power receiving device; and receiving individual parameters from the power receiving device for each of a plurality of states, which are used for detecting foreign objects.

19. A program for causing a computer to perform the method described in claim 17 or 18.

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