Power receiver, power transmitter, wireless power transfer system, program, and control method

Abstract

A wireless power transfer system (10) includes a power transmitter (20) having a power transmitter circuit (400) with a power transmitter coil (22), and a power receiver (100) having a power receiver circuit (500) with a power receiver coil (102). The power transmitter coil (22) is energized to perform wireless power transfer to a power receiver coil (102). The power transmitter (20) includes a power-transmitter control unit (70) that transmits a test radio wave having a predetermined power waveform before performing wireless power transfer. The test radio wave has a waveform corresponding to an output characteristic of the power transmitter circuit (400). The power receiver (100) includes a power-receiver control unit (230) that determines whether power has been normally transmitted by the test radio wave, determines the output characteristic of the power transmitter circuit (400) based on the waveform of the test radio wave, and changes at least determination of whether the wireless power transfer is possible based on the determined output characteristic.

Description

POWER RECEIVER, POWER TRANSMITTER, WIRELESS POWER TRANSFER SYSTEM, PROGRAM, AND CONTROL METHODCross Reference

[0001] This application is based on Japanese Patent Application No. 2025-019560 filed on February 7, 2025, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a power receiver, a power transmitter, a wireless power transfer system, a program, and a control method.

[0003] Conventionally, as described in, for example, Patent Literature 1, a wireless power transfer system is known, which includes a power transmitter circuit having a power transmitter coil arranged along the travel path of a vehicle, and a power receiver circuit provided in the vehicle and having a power receiver coil, wherein wireless power transfer is performed from the power transmitter coil to the power receiver coil.

[0004] JP 2024-122073 A

[0005] In a case where the power transmitter circuit does not have an output characteristic required by the power receiver circuit, disadvantages may occur. For example, a large current may flow from the power receiver circuit to the in-vehicle battery during the wireless power transfer.

[0006] It is a main object of the present disclosure to provide a power receiver, a power transmitter, a wireless power transfer system, a program, and a control method, which are capable of suppressing occurrence of disadvantages caused by a difference in output characteristics.

[0007] According to an aspect of the present disclosure, a power receiver is for a wireless power transfer system including a vehicle-side device and a ground-side device. One of the vehicle-side device and the ground-side device is a power transmitter having a power transmitting antenna and a power transmitter circuit. Another of the vehicle-side device and the ground-side device is the power receiver having a power receiving antenna and a power receiver circuit. The power transmitting antenna is configured to be energized to perform wireless power transfer to the power receiving antenna. The power transmitter is configured to transmit a test radio wave having a power waveform that includes one or multiple predetermined cycles, before performing the wireless power transfer. The waveform of the test radio wave corresponds to an output characteristic of the power transmitter circuit. The power receiver includes a power transmission determination unit configured to determine whether power has been normally transmitted via the test radio wave and determine the output characteristic of the power transmitter circuit based on the waveform of the test radio wave. The power receiver includes a power-receiver control unit configured to change, based on the output characteristic identified by the power transmission determination unit, at least one of control related to the wireless power transfer, a configuration of the power receiver circuit, and determination of whether the wireless power transfer is possible.

[0008] According to the above configuration, even when a combination of the power receiver circuit and the power transmitter circuit is not appropriate, the occurrence of the above-described disadvantages can be suppressed.

[0009] According to an aspect of the present disclosure, a power transmitter is for a wireless power transfer system including a vehicle-side device and a ground-side device. One of the vehicle-side device and the ground-side device is the power transmitter having a power transmitting antenna and a power transmitter circuit. Another of the vehicle-side device and the ground-side device is a power receiver having a power receiving antenna and a power receiver circuit. The power transmitting antenna is configured to be energized to perform wireless power transfer to the power receiving antenna. The power transmitter includes a power-transmitter control unit configured to transmit a test radio wave having a power waveform that includes one or multiple predetermined cycles, before performing the wireless power transfer. The waveform of the test radio wave corresponds to an output characteristic of the power transmitter circuit.

[0010] According to the above configuration, even when a combination of the power receiver circuit and the power transmitter circuit is not appropriate, the occurrence of the above-described disadvantages can be suppressed.

[0011] According to an aspect of the present disclosure, a wireless power transfer system includes a vehicle-side device and a ground-side device. One of the vehicle-side device and the ground-side device is a power transmitter having a power transmitting antenna and a power transmitter circuit. Another of the vehicle-side device and the ground-side device is a power receiver having a power receiving antenna and a power receiver circuit. The power transmitting antenna is configured to be energized to perform wireless power transfer to the power receiving antenna. The power transmitter includes a power-transmitter control unit configured to transmit a test radio wave having a power waveform that includes one or multiple predetermined cycles, before performing the wireless power transfer. The waveform of the test radio wave corresponds to an output characteristic of the power transmitter circuit. The power receiver includes a power transmission determination unit configured to determine whether power has been normally transmitted via the test radio wave and determine the output characteristic of the power transmitter circuit based on the waveform of the test radio wave. The power receiver includes a power-receiver control unit configured to change, based on the output characteristic identified by the power transmission determination unit, at least one of control related to the wireless power transfer, a configuration of the power receiver circuit, and determination of whether the wireless power transfer is possible.

[0012] According to the above configuration, even when the combination of the power receiver circuit and the power transmitter circuit is not appropriate, the occurrence of the above-described disadvantages can be suppressed.

[0013] According to an aspect of the present disclosure, a program is for a power receiver of a wireless power transfer system. The wireless power transfer system includes a vehicle-side device and a ground-side device. One of the vehicle-side device and the ground-side device is a power transmitter having a power transmitting antenna and a power transmitter circuit. Another of the vehicle-side device and the ground-side device is the power receiver having a power receiving antenna and a power receiver circuit. The power transmitting antenna is configured to be energized to perform wireless power transfer to the power receiving antenna. The power transmitter is configured to transmit a test radio wave having a power waveform that includes one or multiple predetermined cycles, before performing the wireless power transfer. The waveform of the test radio wave corresponds to an output characteristic of the power transmitter circuit. The program causes the power receiver to execute: a power transmission determination step of determining whether power has been normally transmitted via the test radio wave, and determining the output characteristic of the power transmitter circuit based on the waveform of the test radio wave; and a power-receiver control step of changing, based on the output characteristic identified by the power transmission determination step, at least one of control related to the wireless power transfer, a configuration of the power receiver circuit, and determination of whether the wireless power transfer is possible.

[0014] According to the above configuration, even when the combination of the power receiver circuit and the power transmitter circuit is not appropriate, the occurrence of the above-described disadvantages can be suppressed.

[0015] According to an aspect of the present disclosure, a control method is performed by a power receiver of a wireless power transfer system. The wireless power transfer system includes a vehicle-side device and a ground-side device. One of the vehicle-side device and the ground-side device is a power transmitter having a power transmitting antenna and a power transmitter circuit. Another of the vehicle-side device and the ground-side device is the power receiver having a power receiving antenna and a power receiver circuit. The power transmitting antenna is configured to be energized to perform wireless power transfer to the power receiving antenna. The power transmitter is configured to transmit a test radio wave having a power waveform that includes one or multiple predetermined cycles, before performing the wireless power transfer. The waveform of the test radio wave corresponds to an output characteristic of the power transmitter circuit. The method includes: a power transmission determination step of determining whether power has been normally transmitted via the test radio wave, and determining the output characteristic of the power transmitter circuit based on the waveform of the test radio wave; and a power-receiver control step of changing, based on the output characteristic identified by the power transmission determination step, at least one of control related to the wireless power transfer, a configuration of the power receiver circuit, and determination of whether the wireless power transfer is possible.

[0016] According to the above configuration, even when the combination of the power receiver circuit and the power transmitter circuit is not appropriate, the occurrence of the above-described disadvantages can be suppressed.

[0017] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.FIG. 1 is an overall configuration diagram of the wireless power transfer system according to the first embodiment.FIG. 2 is an overall configuration diagram of the wireless power transfer system.FIG. 3 is a diagram illustrating the power transmitter and the power receiver.FIG. 4 is a diagram illustrating a configuration of wide-area wireless communication between the power transmitter and a vehicle.FIG. 5 is a diagram illustrating an example of an appropriate combination of a power transmitter circuit and a power receiver circuit of the SS system.FIG. 6 is a diagram illustrating an example of an appropriate combination of a power transmitter circuit and a power receiver circuit of the Double-LCC system.FIG. 7 is a diagram illustrating an example of a case where the combination of the power transmitter circuit and the power receiver circuit is not an appropriate combination.FIG. 8 is a flowchart of the power supply start process.FIG. 9 is a time chart illustrating a power waveform during tracking.FIG. 10 is a block diagram of the information acquisition unit according to the modification.FIG. 11 is a configuration diagram of the power receiver circuit according to the second embodiment.FIG. 12 is a flowchart of the power supply start process according to the second embodiment.FIG. 13 is a flowchart of the power supply start process according to the third embodiment.FIG. 14 is a configuration diagram of the power receiver circuit according to the fourth embodiment.FIG. 15 is a flowchart of the power supply start process according to the fourth embodiment.FIG. 16 is a configuration diagram of the power receiver circuit according to the fifth embodiment.FIG. 17 is a configuration diagram of the power receiver circuit according to the sixth embodiment.FIG. 18 is a configuration diagram of the power receiver circuit according to the seventh embodiment.FIG. 19 is a configuration diagram of the power receiver circuit according to the eighth embodiment.FIG. 20 is a configuration diagram of the power receiver circuit according to the ninth embodiment.

[0018] Hereinafter, a plurality of embodiments of the present disclosure will be described with reference to the drawings. In a plurality of embodiments, functionally and / or structurally corresponding and / or associated portions may be provided with the same reference numerals or reference numerals differing in one hundred or more places. For a corresponding portion and / or an associated portion, reference may be made to descriptions of other embodiments.

[0019] First Embodiment 　　　　　　 Hereinafter, the first embodiment embodying a wireless power transfer system according to the present disclosure will be described with reference to the drawings.

[0020] First, an overall configuration of a wireless power transfer system will be described. As illustrated in FIGS. 1, 2, and 3, a wireless power transfer system 10 includes a power transmitter 20 and a power receiver 100. The power receiver 100 is a vehicle-side device mounted on a vehicle 11 as a mobile body traveling on a road RS. The vehicle 11 is, for example, an electric car or a hybrid car. Power is supplied from the power transmitter 20 to the power receiver 100 while the vehicle 11 is traveling or stopped. The wireless power transfer system 10 performs wireless power transfer from the power transmitter 20 to the power receiver 100 by magnetic field resonance coupling (magnetic field resonance). The wireless power transfer system 10 is referred to as a dynamic wireless power transfer (D-WPT) system.

[0021] The power transmitter 20 is a ground-side device including a power-transmitter coil unit 21 and a transmission power supply unit 51 that supplies power to the power-transmitter coil unit 21. The power transmitter 20 is, for example, a stationary device. The power-transmitter coil unit 21 is installed (for example, embedding) on the road RS, a parking lot, or the like. The transmission power supply unit 51 is installed, for example, beside the road RS. The power-transmitter coil unit 21 is connected to the transmission power supply unit 51. The transmission power supply unit 51 is connected to an AC power supply 15, and supplies AC power of the AC power supply 15 to the power-transmitter coil unit 21. The AC power supply 15 is, for example, a commercial power supply. A plurality of the power-transmitter coil units 21 is disposed along the lane of the road RS. FIG. 2 illustrates an example in which four power-transmitter coil units 21 disposed side by side along the road RS are connected to one transmission power supply unit 51. That is, one transmission power supply unit 51 is provided for every four power-transmitter coil units 21.

[0022] The configuration is not limited to the configuration in which one transmission power supply unit 51 is provided for the plurality of the power-transmitter coil units 21, and one transmission power supply unit 51 may be provided for one power-transmitter coil unit 21.

[0023] The transmission power supply unit 51 includes a PFC circuit 61, an inverter 60, and a filter circuit 52. The PFC circuit 61 includes an AC / DC converter and is connected to the AC power supply 15. Switching control of a switching element (for example, IGBTs or MOSFETs) included in the PFC circuit 61 improves the power factor of the AC power input from the AC power supply 15, and converts the input AC power into DC power. In the present embodiment, the PFC circuit 61 functions as a DC voltage source.

[0024] The inverter 60 is connected to the PFC circuit 61. The switching elements (for example, IGBTs or MOSFETs) S1H, S1L, S2H, and S2L included in the inverter 60 are subjected to switching control, whereby the DC power input from the PFC circuit 61 is converted into AC power.

[0025] The filter circuit 52 removes noise included in the AC current input from the inverter 60, and supplies the AC current from which the noise has been removed to the power-transmitter coil unit 21. The filter circuit 52 is, for example, an LC filter including a coil and a capacitor. As the filter circuit 52, circuits having various configurations are used, and specifically, for example, a T-type filter circuit may be used.

[0026] The power-transmitter coil unit 21 includes a power transmitter coil 22 (corresponding to a “power transmitting antenna”), a power-transmitter resonant circuit 30, and a power-transmitter communication coil 40. The power-transmitter resonant circuit 30 supplies the AC power supplied from the filter circuit 52 to the power transmitter coil 22. As the power-transmitter resonant circuit 30, various known resonant circuits such as a circuit including a resonant capacitor can be used.

[0027] In the present embodiment, the inverter 60, the filter circuit 52, and the power-transmitter resonant circuit 30 constitute a power transmitter circuit 400.

[0028] The power receiver 100 includes a power-receiver coil unit 101 and a power-receiver power supply unit 181. The power-receiver coil unit 101 includes a power receiver coil 102 (corresponding to a “power receiving antenna”). The power-receiver coil unit 101 is provided at the bottom of the vehicle body of the vehicle 11. The power-receiver coil unit 101 is provided at the bottom of the vehicle body so as to face the ground face. When the vehicle 11 travels on the road RS in which the power transmitter coil 22 is embedded, the ground power transmitter coil 22 and the power receiver coil 102 included in the vehicle 11 face each other in the vertical direction.

[0029] The power receiver 100 includes a power-receiver resonant circuit 140. The power receiver coil 102 is connected to the power-receiver resonant circuit 140. Power is transmitted from the power transmitter coil 22 to the power receiver coil 102. The power receiver coil 102 supplies the received power to the power-receiver resonant circuit 140. As the power-receiver resonant circuit 140, various known resonant circuits such as a circuit including a resonant capacitor can be used.

[0030] The power receiver 100 includes a filter circuit 182, a rectifier circuit 200 functioning as a DC / AC conversion circuit, and a smoothing capacitor 210. The filter circuit 182 removes noise included in the AC current input from the power-receiver resonant circuit 140, and supplies the AC current from which the noise has been removed to the rectifier circuit 200. The filter circuit 182 of the present embodiment is, for example, an LC filter including a reactor and a capacitor.

[0031] The rectifier circuit 200 converts the input alternating current into a direct current to output the direct current. The rectifier circuit 200 is, for example, a full-bridge circuit including a semiconductor switching element or a diode rectifier circuit. The first end of the smoothing capacitor 210 is connected to the high potential output terminal of the rectifier circuit 200. The second end of the smoothing capacitor 210 is connected to the low potential output terminal of the rectifier circuit 200. The rectifier circuit 200 is referred to as an electronic rectification box (ERB).

[0032] In the present embodiment, the power-receiver resonant circuit 140, the filter circuit 182, and the rectifier circuit 200 constitute a power receiver circuit 500.

[0033] The vehicle 11 includes a high potential main switch 301H, a low potential main switch 301L, and a high-voltage storage battery 300 as a power storage unit. The high potential main switch 301H and the low potential main switch 301L are relays (specifically, the mechanical relays), for example. A positive electrode terminal of the high-voltage storage battery 300 is connected to a high potential output terminal of the rectifier circuit 200 via the high potential main switch 301H. A negative electrode terminal of the high-voltage storage battery 300 is connected to the low potential output terminal of the rectifier circuit 200 via the low potential main switch 301L. The high-voltage storage battery 300 is a secondary battery that can be charged and discharged, and has a rated voltage of, for example, several hundred V. The high-voltage storage battery 300 is, for example, a lithium ion storage battery or a nickel-metal hydride storage battery.

[0034] The vehicle 11 includes a traveling inverter 310 and a rotation electrical machine 320. The traveling inverter 310 is a three-phase inverter, and is connected to the high-voltage storage battery 300 via the high potential main switch 301H and the low potential main switch 301L. The armature winding of the rotation electrical machine 320 is connected to the upper and lower arm switches constituting the traveling inverter 310. When the upper and lower arm switches of the traveling inverter 310 are subjected to switching control in a state where the high potential main switch 301H and the low potential main switch 301L are turned on, the traveling inverter 310 converts DC power supplied from the high-voltage storage battery 300 into AC power and supplies the AC power to the armature winding. As a result, the rotor of the rotation electrical machine 320 rotates, and the wheels 12 (drive wheels) of the vehicle 11 rotate by the rotational power of the rotor. As a result, the vehicle 11 travels.

[0035] In the present embodiment, the high-voltage storage battery 300 corresponds to a “device to be powered”.

[0036] The transmission power supply unit 51 constituting the power transmitter 20 includes a power-transmitter control unit 70. The power-transmitter control unit 70 includes a power-transmitter controller 71. The power-transmitter controller 71 is an electronic control unit (ECU) that performs various kinds of control of the power transmitter 20, and includes a processor as hardware, a storage unit, and a communication bus that connects the processor and the storage unit.

[0037] The storage unit includes a memory and a storage as hardware. The memory is a storage device for storing data used for processing of the power-transmitter controller 71. The memory provides, for example, a work area for the processor to temporarily use when the processor performs processing. The memory includes, for example, a ROM or a RAM. The storage is a storage device that stores various programs and data to be read and executed by the processor, and is a non-transitory tangible storage medium. The storage includes, for example, an HDD or a flash memory. The storage stores program information and the like for processing to be described later.

[0038] The power-receiver power supply unit 181 constituting the power receiver 100 includes a power-receiver control unit 230. The power-receiver control unit 230 includes a power-receiver controller 231. The power-receiver controller 231 is an ECU that performs various types of control of the power receiver 100, and includes a processor as hardware, a storage unit, and a communication bus that connects the processor and the storage unit.

[0039] The storage unit includes a memory and a storage as hardware. The memory is a storage device for storing data used for processing of the power-receiver controller 231. The memory provides, for example, a work area for the processor to temporarily use when the processor performs processing. The memory includes, for example, a ROM or a RAM. The storage is a storage device that stores various programs and data to be read and executed by the processor, and is a non-transitory tangible storage medium. The storage includes, for example, an HDD or a flash memory. The storage stores program information and the like for processing to be described later.

[0040] The power-transmitter controller 71 performs switching control of the PFC circuit 61 and switching control of the inverter 60. By switching control of the inverter 60, a high-frequency AC voltage is applied to the power transmitter coil 22. As a result, a high-frequency current flows through the power transmitter coil 22, and a magnetic field for power transfer is generated in the power transmitter coil 22.

[0041] In the present embodiment, the power-transmitter controller 71 performs the switching control of the inverter 60 so that the frequency of the high-frequency voltage applied to the power transmitter coil 22 is a first specified frequency (specifically, 85 kHz) of 10 kHz or more and 100 GHz or less. The resonance frequency of the power-transmitter resonant circuit 30 and the power-receiver resonant circuit 140 is set to the frequency same as the first specified frequency or a frequency close to the first specified frequency.

[0042] When the magnetic field generated in the power transmitter coil 22 is interlinked with the power receiver coil 102 of the vehicle 11, a high-frequency current that fluctuates at the frequency of the high-frequency current flowing through the power transmitter coil 22 flows through the power receiver coil 102. The high-frequency current flowing through the power receiver coil 102 is supplied to the rectifier circuit 200 via the power-receiver resonant circuit 140 and the filter circuit 182. The rectifier circuit 200 converts the supplied alternating current into a direct current to output the direct current. In a state where the high potential main switch 301H and the low potential main switch 301L are turned on, the output current of the rectifier circuit 200 is supplied to the high-voltage storage battery 300 and the traveling inverter 310.

[0043] The vehicle 11 includes a low-voltage storage battery 302. The rated voltage of the low-voltage storage battery 302 is lower than the rated voltage of the high-voltage storage battery 300. The low-voltage storage battery 302 is, for example, a lead-acid battery. Power is supplied from the low-voltage storage battery 302 to the power-receiver controller 231, whereby the power-receiver controller 231 is operable.

[0044] The power receiver 100 and the power transmitter 20 have a configuration for communication between the power receiver 100 and the power transmitter 20. Specifically, the power-receiver coil unit 101 constituting the power receiver 100 includes a power-receiver communication coil 170 (corresponding to a “power-receiver communication antenna”). The power-receiver control unit 230 includes a power-receiver communication device 240 (corresponding to a "power-receiver communication unit").

[0045] The power-transmitter coil unit 21 constituting the power transmitter 20 includes the power-transmitter communication coil 40 (corresponding to a “power-transmitter communication antenna”). The power-transmitter control unit 70 includes a power-transmitter communication device 80. The power-receiver communication coil 170 and the power-transmitter communication coil 40 are communication coils for performing narrow-area wireless communication. The narrow-area wireless communication is communication with a communication distance of less than 10 meters (for example, up to 3 meters). The narrow-area wireless communication is communication having a shorter communication distance than wide-area wireless communication.

[0046] Various types of short-range wireless communication can be used as the narrow-area wireless communication, and for example, communication conforming to any communication standard formulated by IEEE, ISO, IEC, or the like is used. Specifically, for example, Wi-Fi (registered trademark), Bluetooth (registered trademark), ZigBee (registered trademark), radio frequency identification (RFID), or dedicated short range communication (DSRC) is used as the narrow-area wireless communication.

[0047] The power-receiver communication device 240 is connected to the power-receiver controller 231. The power-receiver communication coil 170 is connected to the power-receiver communication device 240. The power-receiver controller 231 controls the power-receiver communication device 240 in order to supply a signal to the power-receiver communication coil 170 at the time of transmission. For example, the power-receiver controller 231 controls the power-receiver communication device 240 in order to supply a power supply request signal COMM to the power-receiver communication coil 170. The power supply request signal COMM is a signal requesting the power transmitter coil 22 near the vehicle 11 to transmit power to the power receiver coil 102.

[0048] The power-receiver control unit 230 supplies the power-receiver communication coil 170 with the vehicle signal, the power supply request signal COMM being included in one frame. As a result, a high-frequency voltage is applied from the power-receiver communication device 240 to the power-receiver communication coil 170. As a result, a high-frequency current flows through the power-receiver communication coil 170, and a magnetic field for information communication is generated in the power-receiver communication coil 170. In the present embodiment, the power supply request signal includes ID information identifying the vehicle 11 and a required power Weq that is a required value of the power supply to the vehicle 11.

[0049] When the magnetic field generated from the power-receiver communication coil 170 interlinks the power-transmitter communication coil 40 in a state where the power-receiver coil unit 101 of the vehicle 11 approaches the ground power-transmitter coil unit 21, a high-frequency current flows through the power-transmitter communication coil 40. The high-frequency current is input to the power-transmitter communication device 80. The power-transmitter communication device 80 recognizes information based on the input signal of the power-transmitter communication coil 40. For example, the power-transmitter communication device 80 recognizes the presence or absence of the power supply request and the ID information based on the input power supply request signal COMM of the power-transmitter communication coil 40. In addition, the power-transmitter communication device 80 acquires the required power Weq of the vehicle 11 having the recognized ID information based on the power supply request signal COMM. The information recognized by the power-transmitter communication device 80 is input to the power-transmitter controller 71.

[0050] In the present embodiment, the power-receiver controller 231 controls the power-receiver communication device 240 so that the frequency of the high-frequency voltage applied to the power-receiver communication coil 170 is a second specified frequency of 10 kHz or more and 100 GHz or less at the time of signal transmission. In the present embodiment, the second specified frequency is a frequency deviated from the first specified frequency, specifically, a frequency (specifically, 13.56 MHz) higher than the first specified frequency.

[0051] The power-transmitter controller 71 can determine whether to energize the power transmitter coil 22 based on the input signal from the power-transmitter communication device 80. Specifically, the power-transmitter controller 71 applies a high-frequency voltage to the power transmitter coil 22 by performing switching control of the inverter 60 and the PFC circuit 61 on condition that it is determined that there is a power supply request based on an input signal from the power-transmitter communication device 80.

[0052] Specifically, when determining that there is no power supply request, the power-transmitter controller 71 stops the switching control of the PFC circuit 61 and the inverter 60. As a result, the switching elements of the PFC circuit 61 and the inverter 60 are kept off, and the power transmitter coil 22 is not energized.

[0053] On the other hand, when determining that there is a power supply request, the power-transmitter controller 71 applies a high-frequency voltage to the power transmitter coil 22 by performing switching control of the PFC circuit 61 and the inverter 60 over a predetermined period. As a result, a high-frequency current flows through the power transmitter coil 22 over a predetermined period. In this case, power is contactlessly supplied from the power transmitter coil 22 to the power receiver coil 102 facing the power transmitter coil 22 in the vertical direction. After energizing the power transmitter coil 22 for a predetermined period, the power-transmitter controller 71 does not energize the power transmitter coil 22 until it is determined next time that there is a power supply request.

[0054] The power-transmitter controller 71 performs the frequency control when the high-frequency voltage is applied to the power transmitter coil 22. The frequency control is control to adjust an active power Wact supplied from the inverter 60 to the filter circuit 52 by adjusting a frequency fout of the output voltage from the inverter 60 to the filter circuit 52. The power-transmitter controller 71 alternately turns on a set of the first upper arm switch S1H and the second lower arm switch S2L and a set of the first lower arm switch S1L and the second upper arm switch S2H in order to adjust the frequency fout of the output voltage based on the required power Weq.

[0055] The power-receiver communication device 240 has a reception function similar to that of the power-transmitter communication device 80, and the power-transmitter communication device 80 has a transmission function similar to that of the power-receiver communication device 240. The power-transmitter communication device 80 can transmit a signal, and the signal (information) transmitted from the power-transmitter communication device 80 can be received by the power-receiver communication device 240.

[0056] FIG. 4 is a schematic diagram for describing wide-area wireless communication in the wireless power transfer system 10. In the wireless power transfer system 10, each vehicle 11 can communicate with each power transmitter 20 via the communication network 16. The communication network 16 includes, for example, a wide area network (WAN) which is a public communication network such as the Internet, a telephone communication network of a mobile phone, an information communication network of ETC, and an information communication network of a road traffic information communication system (vehicle information and communication system: VICS (registered trademark)). The wide-area wireless communication is communication having a longer communication distance than the narrow-area wireless communication. The wide-area wireless communication is communication with a communication distance of, for example, 10 meters to 10 kilometers. As the wide-area wireless communication, for example, 3GPP (registered trademark), 4G, LTE, and 5G, which are formulated by IEEE, or WiMAX (registered trademark) is used.

[0057] The vehicle 11 includes a position sensor 330, a navigation device 331, and a communication unit 332. The position sensor 330 is a sensor that detects the current position of the vehicle 11, and is, for example, a GPS sensor. The storage unit (for example, storage) of the navigation device 331 stores map information including road information. The navigation device 331 receives current position information and weather information of the vehicle 11 detected by the position sensor 330. The power-transmitter control unit 70 of the power transmitter 20 includes a communication unit 90. The communication unit 332 of the vehicle 11 and the communication unit 90 of the power-transmitter control unit 70 perform wide-area wireless communication via the communication network 16.

[0058] The wireless power transfer system 10 includes a server 410. The server 410 is, for example, a cloud server, and includes a server control unit 411 and a communication unit 412. The server control unit 411 is an electronic control unit (ECU) that performs various kinds of control of the server 410, and includes a processor as hardware, a storage unit, and a communication bus that connects the processor and the storage unit. The storage unit includes a memory and a storage as hardware. The memory is a storage device for storing data used for processing of the server control unit 411. The memory provides, for example, a work area for the processor to temporarily use when the processor performs processing. The memory includes, for example, a ROM or a RAM. The storage is a storage device that stores various programs and data to be read and executed by the processor, and is a non-transitory tangible storage medium. The storage includes, for example, an HDD or a flash memory. The storage stores program information and the like for processing to be described later.

[0059] The server control unit 411 is connected to the communication unit 412. The server control unit 411 performs wide-area wireless communication with the communication unit 332 of the vehicle 11 and the communication unit 90 of the power-transmitter control unit 70 via the communication unit 412 and the communication network 16.

[0060] For example, program information stored in a non-transitory tangible storage medium is installed in the storage units of the power-receiver controller 231, the power-transmitter controller 71, and the server control unit 411. The storage medium is, for example, a USB memory, a CD-ROM, or a DVD. Furthermore, for example, program information transmitted via a communication network 16 such as Over The Air (OTA) is installed in the storage unit.

[0061] An output characteristic of the power transmitter circuit 400 and an output characteristic of the power transmitter circuit 400 required by the power receiver circuit 500 will be described. Here, the output characteristic indicates what kind of current or voltage the power is supplied to a power transmission target (device to be powered or the like) to be a power supply destination, that is, indicates the characteristic. The output characteristic includes, for example, a current source characteristic of supplying power at a constant current to a power transmission target that is a power supply destination, and a voltage source characteristic of supplying power at a constant voltage to the power transmission target. Although there is an intermediate characteristic between the current source characteristic and the voltage source characteristic, the characteristic is roughly classified into a characteristic close to the current source characteristic or a characteristic close to the voltage source characteristic. In the present embodiment, a circuit having the characteristics close to the current source characteristic and a circuit having the current source characteristic are collectively referred to as a current source, and a circuit having characteristics close to the voltage source characteristic and a circuit having the voltage source characteristic are collectively referred to as a voltage sources.

[0062] In order to identify the output characteristic, the current and the voltage may be measured while changing the load at the time of power supply. In order to identify the output characteristic of the power transmitter circuit 400, the current and the voltage flowing from the power transmitter circuit 400 to power transmitter coil 22 may be measured. In order to identify the output characteristic of the power receiver circuit 500, the current and the voltage flowing from the power transmitter circuit 400 to the high-voltage storage battery 300 may be measured. The output characteristic may be identified from the circuit configuration in some cases. In addition, when the output characteristic of the power transmitter circuit 400 required by the power receiver circuit 500 matches the output characteristic of the power transmitter circuit 400, it is indicated that the combination of the power transmitter circuit 400 and the power receiver circuit 500 is appropriate, and the power receiver circuit 500 is compatible with the output characteristic of the power transmitter circuit 400. When having compatibility, the power receiver circuit 500 can appropriately receive power from the power transmitter circuit 400.

[0063] Next, a combination of the output characteristic of the power transmitter circuit 400 with respect to the output characteristic of the power receiver circuit 500 will be described. FIGS. 5 and 6 illustrate examples of representative combinations.

[0064] FIG. 5 illustrates the wireless power transfer system 10 of the SS system. The power transmitter circuit 400 of this system includes a band-pass filter as the filter circuit 52. The band-pass filter includes a parallel capacitor 53A connected in parallel to the power transmitter coil 22, a series capacitor 53B connected in series to the power transmitter coil 22, and an inductor 53C connected in series to the series capacitor 53B. The power transmitter circuit 400 includes two series capacitors 23 as the power-transmitter resonant circuit 30. One end of the power transmitter coil 22 is connected to the first end of each series capacitor 23. The second end of each of the series capacitors 23 is connected to the parallel capacitor 53A of the band-pass filter. In the present embodiment, the output characteristic of the power transmitter circuit 400 refers to an output characteristic from the power-transmitter resonant circuit 30 when viewed from the power transmitter coil 22.

[0065] The power receiver circuit 500 of the wireless power transfer system 10 of the SS system includes a band-pass filter as the filter circuit 182. The band-pass filter includes a parallel capacitor 183A connected in parallel to the power receiver coil 102, a series capacitor 183B connected in series to the power receiver coil 102, and an inductor 183C connected in series to a series capacitor 183B. In addition, the power receiver circuit 500 includes two series capacitors 141 as the power-receiver resonant circuit 140. One end of the power receiver coil 102 is connected to the first end of each series capacitor 141. The second end of each of the series capacitors 141 is connected to the parallel capacitor 183A of a band-pass filter.

[0066] In the wireless power transfer system 10 of the SS system, the inverter 60 is supplied with power from the PFC circuit 61 functioning as a voltage source, and switching control is performed so that an output characteristic is a voltage source when viewed from the filter circuit 52. Since the filter circuit 52 does not have a function as an immittance conversion unit that performs immittance conversion, when the inverter 60 serves as a voltage source, the output characteristic from the filter circuit 52 is a voltage source when viewed from the power-transmitter resonant circuit 30 as the power transmission destination. Immittance conversion refers to impedance and admittance conversion. In the present embodiment, when the power source is a current source, the output characteristic is converted into a voltage source, and when the power source is a voltage source, the output characteristic is converted into a current source.

[0067] Since the power-transmitter resonant circuit 30 only includes the two series capacitors 23, when the output characteristic from the filter circuit 52 is a voltage source, the output characteristic from the power-transmitter resonant circuit 30 is a voltage source when viewed from the power transmitter coil 22 as the power transmission destination.

[0068] In addition, in the present embodiment, since the power transmitter coil 22 and the power receiver coil 102 have a function as an immittance conversion unit, the output characteristic is a current source when viewed from the power-receiver resonant circuit 140 as the power transmission destination. In addition, in the present embodiment, since the power-receiver resonant circuit 140 only includes the two series capacitors 141, when the output characteristic from the power receiver coil 102 is a current source, the output characteristic is a current source when viewed from the filter circuit 182 as the power transmission destination.

[0069] Since the filter circuit 182 does not have a function as an immittance conversion unit, the output characteristic from the filter circuit 182 is a current source when viewed from the rectifier circuit 200 as the power transmission destination. As a result, the output characteristic to the rectifier circuit 200 and the high-voltage storage battery 300 is a current source. In the present embodiment, the rectifier circuit 200 performs switching control on the high-voltage storage battery 300 so that its output characteristic is not converted. That is, when viewed from the high-voltage storage battery 300, the output characteristic of the rectifier circuit 200 is a current source.

[0070] In the present embodiment, the output characteristic of the power transmitter circuit 400 required by the power receiver circuit 500 is an output characteristic of the power transmitter circuit 400 that can appropriately receive power by the current power receiver circuit 500, and is determined by the circuit configuration of the power receiver circuit 500, the control by the power-receiver controller 231, and the device to be powered to which power is supplied from the power receiver circuit 500. When charging, the high-voltage storage battery 300 requests a current source as an output characteristic of a power supply source, and the power receiver circuit 500 illustrated in FIG. 5 converts the output characteristic of the power transmitter circuit 400 and supplies power to the high-voltage storage battery 300. For this reason, the output characteristic of the power transmitter circuit 400 required by the power receiver circuit 500 illustrated in FIG. 5 is a voltage source. Whether the power receiver circuit 500 converts the output characteristic of the power transmitter circuit 400 and supplies power to the device to be powered (such as the high-voltage storage battery 300) depends on the circuit configuration of the power receiver circuit 500 and the control content of the power-receiver control unit 230 for the power receiver circuit 500.

[0071] In FIG. 5, the power transmitter circuit 400 may not include the filter circuit 52, or power receiver circuit 500 may not include the filter circuit 182.

[0072] FIG. 6 illustrates the wireless power transfer system 10 of the Double-LCC system. The power transmitter circuit 400 of this system includes an immittance filter as the filter circuit 52. The immittance filter includes a first inductor 54A connected in series to the power transmitter coil 22, a second inductor 54C connected in series to the first inductor 54A, and a capacitor 54B. The capacitor 54B is connected to a connection point between the first inductor 54A and the second inductor 54C. Further, the power transmitter circuit 400 includes two series capacitors 23 as the power-transmitter resonant circuit 30 as in FIG. 5.

[0073] The power receiver circuit 500 of the wireless power transfer system 10 of the Double-LCC system includes an immittance filter as the filter circuit 182. The immittance filter includes a first inductor 184A connected in series to the power receiver coil 102, a second inductor 184C connected in series to the first inductor 184A, and a capacitor 184B. The capacitor 184B is connected to a connection point between the first inductor 184A and the second inductor 184C. In addition, the power receiver circuit 500 includes two series capacitors 141 as the power-receiver resonant circuit 140 as in FIG. 5.

[0074] In the wireless power transfer system 10 of the Double-LCC system, since the filter circuit 52 has a function as an immittance conversion unit, when the inverter 60 serves as a voltage source, the output characteristic from the filter circuit 52 is a current source when viewed from the power-transmitter resonant circuit 30 as the power transmission destination.

[0075] Since the power-transmitter resonant circuit 30 only includes the two series capacitors 23, when the output characteristic from the filter circuit 52 is a current source, the output characteristic from the power-transmitter resonant circuit 30 is a current source when viewed from the power transmitter coil 22 as the power transmission destination.

[0076] In addition, in the present embodiment, since the power transmitter coil 22 and the power receiver coil 102 have a function as an immittance conversion unit, the output characteristic is a voltage source when viewed from the power-receiver resonant circuit 140 as the power transmission destination. In addition, in the present embodiment, since the power-receiver resonant circuit 140 only includes the two series capacitors 141, when the output characteristic from the power receiver coil 102 serves as a voltage source, the output characteristic is a voltage source when viewed from the filter circuit 182 as the power transmission destination.

[0077] Since the filter circuit 182 has a function as an immittance conversion unit, the output characteristic from the filter circuit 52 is a current source when viewed from the rectifier circuit 200 as the power transmission destination. As a result, the power source for the rectifier circuit 200 and the high-voltage storage battery 300 is a current source. The rectifier circuit 200 performs switching control on the high-voltage storage battery 300 so that its output characteristic is not converted.

[0078] When charging, the high-voltage storage battery 300 requests a current source as a power supply source, and the power receiver circuit 500 illustrated in FIG. 6 transmits the output characteristic of the power transmitter circuit 400 to the high-voltage storage battery 300 as it is. For this reason, the output characteristic of the power transmitter circuit 400 required by the power receiver circuit 500 illustrated in FIG. 6 is a current source.

[0079] In FIG. 6, in the filter circuit 52 of the power transmitter circuit 400, the first inductor 54A of the power transmitter coil 22 may not be provided, and the function of the first inductor 54A may be substituted by the inductance of the power transmitter coil 22. In the filter circuit 182 of the power receiver circuit 500, the first inductor 184A of the power receiver coil 102 may not be provided, and the function of the first inductor 184A may be substituted by the inductance of the power receiver coil 102.

[0080] As illustrated in FIGS. 5 and 6, when viewed from the high-voltage storage battery 300, the output characteristic from the power receiver circuit 500 is a current source. On the other hand, a plurality of specifications of the power transmitter circuit 400 distributed in the market may be set. In addition, a plurality of specifications of the power receiver circuit 500 distributed in the market may be set. In this case, the power transmitter circuit 400 and the power receiver circuit 500 may not be an appropriate combination, and the output characteristic of the power transmitter circuit 400 required by the power receiver circuit 500 may not match the output characteristic of the power transmitter circuit 400. As an example in which the combination is not appropriate, FIG. 7 illustrates a case in which the power transmitter circuit 400 is a circuit of the Double-LCC system (the power transmitter circuit 400 in FIG. 6), and the filter circuit 182 of the power receiver circuit 500 is a band-pass filter instead of an immittance filter (the power receiver circuit 500 in FIG. 5).

[0081] In the case illustrated in FIG. 7, since the output characteristic of the power transmitter circuit 400 is a current source, and the output characteristic of the power transmitter circuit 400 required by the power receiver circuit 500 is a voltage source, the combination is not appropriate. When the combination is not appropriate, the power source for the high-voltage storage battery 300 is a voltage source, which may cause disadvantages. Specifically, when the output voltage of the rectifier circuit 200 is higher than that of the high-voltage storage battery 300 during the wireless power transfer, a large current may flow from the rectifier circuit 200 to the high-voltage storage battery 300. In addition, when the output voltage of the rectifier circuit 200 is lower than that of the high-voltage storage battery 300 during the wireless power transfer, a current may not be supplied from the rectifier circuit 200 to the high-voltage storage battery 300.

[0082] In order to cope with such disadvantages, the power-receiver control unit 230 determines whether the wireless power transfer is possible based on the output characteristic of the power transmitter circuit 400 before power supply to the high-voltage storage battery 300 (device to be powered) is performed. Hereinafter, a flow until power-receiver control unit 230 checks the output characteristic of the power transmitter circuit 400 and starts the wireless power transfer will be described with reference to FIG. 8. FIG. 8 is a flowchart illustrating a flow of the power supply start process executed by the power-receiver controller 231. The power supply start process is executed at a predetermined timing.

[0083] The power-receiver control unit 230 performs wide-area wireless communication via the communication unit 332 to acquire the first power-transmitter information about the power transmitter 20 through which the vehicle 11 is scheduled to pass next (step S1). As a result, the communication unit 332 functions as an information acquisition unit. The communication partner of the power-receiver control unit 230 may be the power transmitter 20 through which the vehicle 11 is scheduled to pass next, or may be the server 410. The power transmitter 20 through which the vehicle 11 is scheduled to pass next can be identified by, for example, position information about the vehicle 11, road information during traveling, and the like.

[0084] The power-transmitter information includes at least an output characteristic of the power transmitter circuit 400. The power-transmitter information may include, in addition to the output characteristic, antenna information related to the power transmitter coil 22, communication standard information related to a communication standard, power information related to transmission power, activation sequence information, and the like.

[0085] The antenna information is information related to the power transmitter coil 22, such as a coil shape (including a size and a power transmission range) of the power transmitter coil 22, the number of the power transmitter coils 22, and inductance of the power transmitter coil 22. The antenna information may include information about the power-transmitter communication coil 40.

[0086] The communication standard information is information about what kind of communication is performed. For example, it is information such as whether wide-area wireless communication is executable, whether narrow-area wireless communication is executable, or whether other communication methods are executable. Furthermore, in a case where narrow-area wireless communication is executable, information about a specific communication standard of narrow-area wireless communication may be included. For example, the communication standard of the narrow-area wireless communication may include information about which communication standard among the communication standards such as Wi-Fi (registered trademark) and Bluetooth (registered trademark) is to be used. Note that, in a case where another communication method (wide-area wireless communication or the like) is executable, information about a specific communication standard of the communication method may be included.

[0087] The activation sequence information is information related to a procedure until wireless power transfer is started. In the present embodiment, the activation sequence information includes that a procedure of first performing wide-area wireless communication, then performing narrow-area wireless communication, then transmitting and receiving a power supply request signal, performing tracking, and finally performing wireless power transfer (main power transfer) is defined.

[0088] The tracking in the present embodiment is to transmit experimentally predetermined power (test radio wave) before starting power supply to the device to be powered (before starting main power transfer), and to check whether the power is appropriately transmitted from the power transmitter coil 22 to the power receiver coil 102.

[0089] The power information is information about an amount of power to be transmitted, an amount of power that can be transmitted from the power transmitter 20, or the like.

[0090] Next, the power-receiver control unit 230 performs narrow-area wireless communication, and acquires second power-transmitter information about the power transmitter 20 through which the vehicle 11 is scheduled to pass next (step S2). In the present embodiment, the second power-transmitter information is acquired by receiving a signal output from the power-transmitter communication coil 40 using the power-receiver communication device 240 and the power-receiver communication coil 170. In the present embodiment, the power-receiver communication device 240 also corresponds to an information acquisition unit.

[0091] The second power-transmitter information includes at least an output characteristic of the power transmitter circuit 400. The second power-transmitter information may include, in addition to the output characteristic, antenna information related to the power transmitter coil 22, communication standard information related to a communication standard, power information related to transmission power, activation sequence information, and the like. In addition, the second power-transmitter information may include information that is not included in the first power-transmitter information, and conversely, may not include information that is included in the first power-transmitter information.

[0092] Next, the power-receiver control unit 230 checks consistency between the first power-transmitter information acquired in step S1 and the second power-transmitter information acquired in step S2 (step S3). In step S3, it is determined whether content of the information included in the first power-transmitter information matches content of the information included in the second power-transmitter information. For example, it is determined whether the output characteristic of the power transmitter circuit 400 included in the first power-transmitter information matches the output characteristic of the power transmitter circuit 400 included in the second power-transmitter information. Specifically, when the output characteristic of the power transmitter circuit 400 included in the first power-transmitter information is the current source, it is determined that the output characteristics match in a case where the output characteristic of the power transmitter circuit 400 included in the second power-transmitter information is the current source, and it is determined that the output characteristics do not match in a case where the output characteristic is the voltage source.

[0093] Note that, as described above, the information included in the first power-transmitter information and the second power-transmitter information may be different from each other. Therefore, it is not checked whether the information included in the first power-transmitter information is included in the second power-transmitter information. It is determined whether the content of the included information matches.

[0094] When the first power-transmitter information and the second power-transmitter information are not consistent with each other (step S3: NO), the power-receiver control unit 230 ends the process. On the other hand, when the first power-transmitter information and the second power-transmitter information are consistent with each other (step S3: YES), the power-receiver control unit 230 determines whether the power receiver circuit 500 is compatible with the power transmitter circuit 400 in the output characteristic included in the power-transmitter information (step S4). In step S4, it is determined whether the output characteristic of the power transmitter circuit 400 matches the output characteristic of the power transmitter circuit 400 required by the power receiver circuit 500, that is, whether the combination of the power transmitter circuit 400 and the power receiver circuit 500 is appropriate. The output characteristic of the power transmitter circuit 400 required by the power receiver circuit 500 is stored in, for example, the storage unit of the power-receiver controller 231.

[0095] For example, when the output characteristic of the power transmitter circuit 400 is the current source, in a case where the output characteristic required by the power receiver circuit 500 (the output characteristic that can be appropriately received by the power receiver circuit 500) is the current source, affirmative determination is made in step S4, and in a case where the output characteristic is the voltage source, negative determination is made in step S4. Similarly, when the output characteristic of the power transmitter circuit 400 is the voltage source, in a case where the output characteristic required by the power receiver circuit 500 is the voltage source, affirmative determination is made in step S4, and in a case where the output characteristic is the current source, negative determination is made in step S4.

[0096] When the determination result of step S4 is negative, the power-receiver control unit 230 ends the process. That is, the power-receiver control unit 230 cancels the wireless power transfer. On the other hand, when the determination result of step S4 is affirmative, the power-receiver control unit 230 transmits the power supply request signal COMM (step S5). When receiving the power supply request signal COMM, the power-transmitter controller 71 causes the power transmitter circuit 400 to transmit experimentally predetermined power (test radio wave), and starts tracking.

[0097] Here, tracking will be described with reference to FIG. 9. FIG. 9 is a time chart schematically illustrating a waveform of power transmitted from the power transmitter 20. When the power supply request signal COMM is transmitted from the power-receiver control unit 230 (time point T10) and the power-transmitter controller 71 receives the power supply request signal COMM, thereafter, a test radio wave TW is transmitted (time point T11). The test radio wave TW has a power waveform of one or a plurality of predetermined cycles. In FIG. 9, a power waveform for one cycle is included. The power waveform of the test radio wave TW varies depending on the output characteristic of the power transmitter circuit 400. In the present embodiment, the output characteristic of the power transmitter circuit 400 is set so that the frequency is different between the case of the voltage source and the case of the current source.

[0098] The power-receiver control unit 230 receives the power transmitted by the tracking by the power receiver circuit 500 (step S6). At the time of receiving power in step S6, a current sensor (not illustrated) measures a power waveform (here, a current waveform) received by the power receiver coil 102. The power-receiver control unit 230 acquires the power waveform of the test radio wave TW measured by the current sensor.

[0099] The power-receiver control unit 230 determines whether tracking has been normally performed (step S7). In step S7, it is determined whether the test radio wave TW transmitted by tracking is a predetermined test radio wave TW. Specifically, it is determined whether the power waveform (amplitude, frequency, and the like) of the test radio wave TW is predetermined. There is no need to completely match the predetermined waveform, and it is required that a difference between the received power waveform and the predetermined power waveform is within a certain error range.

[0100] When the determination result is negative, the power-receiver control unit 230 does not start the wireless power transfer (main power transfer), and ends the process. At this time, the power-receiver control unit 230 may transmit a cancel signal making a notification that the wireless power transfer is cancelled (stopped) via narrow-area wireless communication (or wide-area wireless communication).

[0101] On the other hand, when the determination result in step S7 is affirmative, the power-receiver control unit 230 determines the output characteristic of the power transmitter circuit 400 based on the power waveform of the test radio wave TW, and determines whether the output characteristic matches the output characteristic included in the power-transmitter information (step S8). By the process of steps S7 and S8, the power-receiver control unit 230 corresponds to a power transmission determination unit, and the process of steps S7 and S8 executed by the power-receiver control unit 230 corresponds to a power transmission determination step.

[0102] In step S8, the power-receiver control unit 230 determines whether the output characteristic of the power transmitter circuit 400 is a voltage source or a current source based on the difference in frequency of the test radio wave TW. Then, the power-receiver control unit 230 determines whether the determination result matches the output characteristic included in the power-transmitter information. Here, the output characteristic included in the power-transmitter information is identical to the output characteristic in step S4.

[0103] When the determination result is negative, the power-receiver control unit 230 does not start the wireless power transfer (main power transfer), and ends the process. At this time, the power-receiver control unit 230 may transmit a cancel signal making a notification that the wireless power transfer is cancelled (stopped) by narrow-area wireless communication (or wide-area wireless communication).

[0104] On the other hand, when the determination result of step S8 is affirmative, the power-receiver control unit 230 starts wireless power transfer (main power transfer) (step S9). Specifically, the power-transmitter controller 71 starts main power transfer at time point T12 a predetermined time after time point T10 at which tracking is performed. As a result, power (power PW of the main power transfer) is supplied to the power receiver 100 as illustrated in FIG. 9. On the other hand, the power-receiver control unit 230 supplies power to the high-voltage storage battery 300 to be the device to be powered and charges the high-voltage storage battery 300 after the start of the main power transfer (after time point T12).

[0105] The power-receiver control unit 230 performs short-circuit control of the power receiver coil 102 by the protection circuit (in the present embodiment, the rectifier circuit 200) to restrict power supply to the high-voltage storage battery 300 until the main power transfer is started (until time point T12), and after the start of the main power transfer, releases the short-circuit control, performs rectification by the rectifier circuit 200, and starts power supply to the high-voltage storage battery 300.

[0106] According to the first embodiment, the following effects are obtained.

[0107] The power-receiver control unit 230 determines the output characteristic of the power transmitter circuit 400 based on the power waveform of the test radio wave TW transmitted in the tracking. Then, when the output characteristic determined based on the test radio wave TW is different from the output characteristic included in the power-transmitter information, the wireless power transfer is cancelled. That is, when the output characteristic determined based on the test radio wave TW is different from the output characteristic required by the power receiver circuit 500, the wireless power transfer is cancelled. As a result, in the tracking, it is possible to determine whether the power can be appropriately transmitted and finally check the output characteristic of the power transmitter circuit 400. Therefore, it is possible to appropriately perform power supply or appropriately restrict power supply.

[0108] When the output characteristic acquired in advance by the power-transmitter information is identical to the output characteristic determined by the test radio wave TW during tracking, the power supply to the high-voltage storage battery 300 is started. Therefore, it is possible to more reliably determine that the output characteristics are consistent with each other.

[0109] During tracking, the power supply to the high-voltage storage battery 300 is restricted by performing short-circuit control of the power receiver coil 102 by the rectifier circuit 200 until the output characteristic is checked by the test radio wave TW. Therefore, power supply can be performed more safely.

[0110] The current waveform of the test radio wave TW is measured by the current sensor, and the frequency of the current waveform is measured, whereby the output characteristic can be easily grasped.

[0111] The power-receiver control unit 230 changes determination of whether the wireless power transfer is possible based on the output characteristic of the power transmitter circuit 400 included in the power-transmitter information acquired by the power-receiver communication device 240 or the communication unit 332 before the wireless power transfer is performed. That is, when the output characteristic of the power transmitter circuit 400 matches the output characteristic required by the power receiver circuit 500, and the combination of the power transmitter circuit 400 and the power receiver circuit 500 is appropriate, the wireless power transfer is started. On the other hand, when the output characteristic of the power transmitter circuit 400 does not match the output characteristic required by the power receiver circuit 500, and the combination of the power transmitter circuit 400 and the power receiver circuit 500 is not appropriate, the wireless power transfer is cancelled. As a result, it is possible to appropriately perform power supply or appropriately restrict power supply. Therefore, the processing of steps S1 and S2 corresponds to an information acquisition step executed by the power-receiver control unit 230. The processing of steps S3, S4 and S9 corresponds to a power-receiver control step executed by the power-receiver control unit 230.

[0112] The power-receiver control unit 230 determines whether the power transmitter circuit 400 is compatible with the power receiver circuit 500 based on the output characteristic of the power transmitter circuit 400 included in the power-transmitter information. Then, the power-receiver control unit 230 changes determination of whether the wireless power transfer is possible according to the presence or absence of compatibility. As a result, in a case where there is no compatibility with the power receiver circuit 500, it is possible to restrict power transfer and prevent failure.

[0113] The power-receiver control unit 230 changes determination of whether the wireless power transfer is possible based on the power-transmitter information before transmitting the power supply request signal COMM. Specifically, it is possible to change determination of whether the wireless power transfer is possible before the tracking. As a result, it is possible to reliably prevent the power transmitter from being erroneously started from the power transmitter 20, and it is possible to appropriately perform the power supply or appropriately limit the power supply.

[0114] The power-receiver communication device 240 capable of executing narrow-area wireless communication is provided as the first information acquisition unit, and the communication unit 332 capable of executing wide-area wireless communication is provided as the second information acquisition unit. The power-receiver control unit 230 acquires the first power-transmitter information by at least the communication unit 332 before the wireless power transfer is performed. As a result, since the power-transmitter information can be acquired from a farther distance, it is possible to make preparations such as changing the control in advance.

[0115] The power-receiver communication device 240 and the communication unit 332 acquire the first power-transmitter information and the second power-transmitter information, respectively, before the wireless power transfer is performed, and the power-receiver controller 231 checks whether content of the second power-transmitter information and content of the first power-transmitter information are consistent with each other. Therefore, the output characteristic can be known more accurately. As a result, it is possible to more appropriately perform power supply or appropriately restrict power supply. Therefore, abnormality can be reliably prevented.

[0116] When content of the second power-transmitter information and content of the first power-transmitter information are not consistent with each other, the power-receiver control unit 230 cancels the wireless power transfer. As a result, abnormality can be reliably prevented.

[0117] Modification of First Embodiment 　　　　　　 A modification in which the configuration of the first embodiment is partially changed will be described below.

[0118] In the above embodiment, the frequency of the test radio wave TW is varied depending on the difference in output characteristics. As a modification, at least any of the amplitude, the frequency, the wavelength, the number of waves, the current amount, and the transmission period of the test radio wave TW may be varied according to the output characteristic of the power transmitter circuit 400.

[0119] In the above embodiment, both the first power-transmitter information and the second power-transmitter information are acquired, but only one of the first power-transmitter information and the second power-transmitter information may be acquired.

[0120] In the above embodiment, the consistency between the first power-transmitter information and the second power-transmitter information is determined, but whether the wireless power transfer is possible may be determined based on either of the power-transmitter information.

[0121] In the above embodiment, the procedure until the start of the wireless power transfer may be changed based on the power-transmitter information. For example, in a case where it is determined not to acquire the first power-transmitter information by the wide-area wireless communication based on the activation sequence information, the subsequent processing may be executed based on only the second power-transmitter information. In this case, the consistency of the power-transmitter information is not determined. Similarly, when it is determined not to acquire the second power-transmitter information by the narrow-area wireless communication based on the activation sequence information, the subsequent processing may be executed based on only the first power-transmitter information. In this case, the consistency of the power-transmitter information is not determined. Similarly, in a case where it is determined not to perform tracking based on the activation sequence information, wireless power transfer may be started without checking tracking.

[0122] In the above embodiment, the communication method or the like may be changed based on the antenna information or the communication standard information included in the power-transmitter information. As a result, the control can be more appropriately changed according to the configuration of the power transmitter, the control content, and the like before the wireless power transfer is performed. In addition, the amount of power to be transmitted or the like may be changed based on the power information included in the power-transmitter information. As a result, power can be transmitted with an appropriate amount of power.

[0123] In the first embodiment, the traveling inverter 310 may be the “device to be powered”. In this case, the supply source of the power to the traveling inverter 310 is desirably a voltage source. Accordingly, the output characteristic required by the power receiver circuit 500 in the first embodiment is changed.

[0124] In the above embodiment, inter-vehicle communication for performing wireless communication between the vehicle 11 (host vehicle) and another vehicle around the vehicle may be configured to be available. Then, as illustrated in FIG. 10, an inter-vehicle communication unit 91 that acquires, from another vehicle by inter-vehicle communication, the power-transmitter information of the power transmitter 20 through which the vehicle 11 acquired by the another vehicle is scheduled to pass next may be provided. The inter-vehicle communication unit 91 may be part of the information acquisition unit. That is, the inter-vehicle communication unit 91 may be used instead of other information acquisition units (such as narrow-area wireless communication and wide-area wireless communication), or may be used together with other information acquisition units (such as narrow-area wireless communication and wide-area wireless communication).

[0125] In the above embodiment, a position information acquisition unit 92 that acquires position information about the vehicle 11 from a GPS sensor or the like and acquires power-transmitter information of the power transmitter 20 through which the vehicle is scheduled to pass next based on the position information may be provided. For example, the power-transmitter information may be stored in advance in association with each position information, and the power-transmitter information may be read based on the acquired position information about the vehicle 11. Further, the power-transmitter information corresponding to the acquired position information about the vehicle 11 may be acquired from an external server using wide-area wireless communication or the like.

[0126] As illustrated in FIG. 10, the position information acquisition unit 92 may be part of the information acquisition unit. That is, the position information acquisition unit 92 may be used instead of other information acquisition units (such as narrow-area wireless communication and wide-area wireless communication), or may be used together with other information acquisition units (such as narrow-area wireless communication and wide-area wireless communication).

[0127] In the above embodiment, an image recognition unit 93 that captures an image of a sign provided at the road RS through which the vehicle 11 passes and performs image recognition of the captured sign to acquire power-transmitter information of the power transmitter 20 through which the vehicle 11 is scheduled to pass next may be provided. That is, the power-transmitter information displayed on the recognized sign may be acquired. Alternatively, the power-transmitter information stored in advance in the storage unit or the like in association with the sign may be read.

[0128] As illustrated in FIG. 10, the image recognition unit 93 may be part of the information acquisition unit. That is, the image recognition unit 93 may be used instead of other information acquisition units (such as narrow-area wireless communication and wide-area wireless communication), or may be used together with other information acquisition units (such as narrow-area wireless communication and wide-area wireless communication).

[0129] In the above embodiment, a marker recognition unit 94 that recognizes a marker provided at the road RS through which the vehicle 11 passes and acquires power-transmitter information of the power transmitter 20 through which the vehicle 11 is scheduled to pass next based on the marker may be provided. For example, the marker recognition unit 94 may emit a signal such as an electric signal, an optical signal, or a magnetic signal from the marker, and acquire the power-transmitter information by recognizing the signal. At this time, the power-transmitter information may be directly included in the signal, or information about the marker such as the type and position information about the marker may be acquired from the signal from the marker, and the power-transmitter information stored in the storage unit or the external device may be identified from the information about the marker.

[0130] As illustrated in FIG. 10, the marker recognition unit 94 may be part of the information acquisition unit. That is, the marker recognition unit 94 may be used instead of other information acquisition units (such as narrow-area wireless communication and wide-area wireless communication), or may be used together with other information acquisition units (such as narrow-area wireless communication and wide-area wireless communication).

[0131] In the above embodiment, the information acquisition unit includes only two information acquisition units: the second information acquisition unit that acquires the power-transmitter information using the wide-area wireless communication, and the first information acquisition unit that acquires the power-transmitter information using the narrow-area wireless communication; but may include three or more information acquisition units. The information acquisition unit may include any of the inter-vehicle communication unit 91, the position information acquisition unit 92, the image recognition unit 93, and the marker recognition unit 94 described above.

[0132] Second Embodiment 　　　　　　 Hereinafter, the second embodiment will be described with reference to the drawings, focusing on differences from the first embodiment.

[0133] In the first embodiment, when the combination of the power receiver circuit 500 and the power transmitter circuit 400 is not appropriate, the wireless power transfer is cancelled. However, in the second embodiment, the control of the power-receiver control unit 230 is changed to convert the output characteristic from the power receiver circuit 500, and appropriate power is supplied to the high-voltage storage battery 300. Details will be described below.

[0134] As illustrated in FIG. 11, the power receiver circuit 500 according to the second embodiment includes a DC-DC converter 201 between the rectifier circuit 200 and the high-voltage storage battery 300. The DC-DC converter 201 is configured to be capable of transforming the DC voltage input from the rectifier circuit 200 and outputting the transformed DC voltage to the high-voltage storage battery 300. The DC-DC converter 201 is configured to be controlled by the power-receiver controller 231.

[0135] Next, the power supply start process of the second embodiment will be described with reference to FIG. 12. Steps S1 to S9 are similar to those in the first embodiment, and thus description thereof is omitted. In the second embodiment, when the determination result of step S4 is negative, the power-receiver controller 231 performs the switching process for changing the output characteristic (step S10). In step S10, it is determined to change the control of the DC-DC converter 201 in order to change the output characteristic of the power receiver circuit 500. Then, the power-receiver controller 231 advances the process to step S5.

[0136] After performing step S10, when main power transfer (wireless power transfer) is started in step S9, the power-receiver controller 231 performs a process of adjusting the output voltage Vout of the DC-DC converter 201. For example, the power-receiver controller 231 adjusts the output voltage Vout so that a constant current flows through the high-voltage storage battery 300.

[0137] By adjusting the output voltage Vout in this manner, the output voltage from the rectifier circuit 200 to the high-voltage storage battery 300 can be adjusted so as to suppress the occurrence of the above-described disadvantages. That is, substantially, the output characteristic from the rectifier circuit 200 can be changed from the voltage source to the current source by the DC-DC converter 201. As a result, power can be supplied from the rectifier circuit 200 to the high-voltage storage battery 300 without causing overcurrent to flow from the rectifier circuit 200 to the high-voltage storage battery 300. Therefore, the processing of steps S3, S4, S9 and S10 corresponds to a power-receiver control step executed by the power-receiver control unit 230.

[0138] Third Embodiment 　　　　　　 Hereinafter, the third embodiment will be described with reference to the drawings, focusing on differences from the first embodiment.

[0139] In the second embodiment, the DC-DC converter 201 is provided, and the control of the DC-DC converter 201 by the power-receiver controller 231 is changed, so that the output characteristic from the power receiver circuit 500 is changed. On the other hand, in the third embodiment, the output characteristic from the power receiver circuit 500 is changed by changing the control in the rectifier circuit 200 instead of the DC-DC converter 201 without providing the DC-DC converter 201. In the third embodiment, the rectifier circuit 200 is a full-bridge circuit including a semiconductor switching element. Specifically, the configuration may be identical to that of the power receiver circuit 500 in FIG. 5 or 6.

[0140] Next, the power supply start process of the third embodiment will be described with reference to FIG. 13. Steps S1 to S9 are similar to those in the first embodiment, and thus description thereof is omitted. In the third embodiment, when the determination result of step S4 is negative, the power-receiver controller 231 performs the switching process for changing the output characteristic (step S11). In step S11, the power-receiver controller 231 determines to change the control of the rectifier circuit 200. Specifically, the power-receiver controller 231 determines to switch the control of the rectifier circuit 200 from the frequency control to the Duty control. In the Duty control, a set of the first upper arm switch S11H and the second lower arm switch S12L and a set of the first lower arm switch S11L and the second upper arm switch S12H are alternately turned on at a predetermined switching cycle Tsw.

[0141] In the Duty control, a Duty ratio (=Ton / Tsw), which is a ratio of an ON period Tоn of a set of the first upper arm switch S11H and the second lower arm switch S12L (or a set of the first lower arm switch S11L and the second upper arm switch S12H) to the switching cycle Tsw, is adjusted. The larger the Duty ratio, the larger the active power Wact.

[0142] Then, the power-receiver controller 231 advances the process to step S5. After step S11, when main power transfer (wireless power transfer) is started in step S8, the power-receiver controller 231 changes the switching control of the rectifier circuit 200 in order to change the output characteristic. Specifically, the power-receiver controller 231 adjusts the Duty ratio so that a constant current flows through the high-voltage storage battery 300. As a result, the output characteristic from the rectifier circuit 200 can be changed from the voltage source to the current source. Therefore, in the third embodiment, power can be appropriately supplied from the rectifier circuit 200 to the high-voltage storage battery 300 without including the DC-DC converter 201 illustrated in FIG. 11. Therefore, the processing of steps S3, S4, S9 and S11 corresponds to a power-receiver control step executed by the power-receiver control unit 230.

[0143] Fourth Embodiment 　　　　　　 Hereinafter, the fourth embodiment will be described with reference to the drawings, focusing on differences from the first embodiment.

[0144] In the fourth embodiment, the circuit configuration is changed by switching the power receiver circuit 500, and the output characteristic of the power receiver circuit 500 can be changed. More specifically, in the power receiver circuit 500, the presence or absence of a circuit having a function as an immittance conversion unit can be switched. Specifically, the power receiver circuit 500 is a circuit illustrated in FIG. 14. In the fourth embodiment, the power receiver circuit 500 serving as a base is a circuit of the Double-LCC system.

[0145] The power receiver circuit 500 includes a characteristic changeover switch SW (in the fourth embodiment, the characteristic changeover switch SWA). The characteristic changeover switch SWA is a switch that energizes and de-energizes a bypass path connecting an output unit of the power-receiver resonant circuit 140 and an input unit of the rectifier circuit 200. When the characteristic changeover switch SWA is turned off, the output unit of the power-receiver resonant circuit 140 and the input unit of the rectifier circuit 200 are connected via the filter circuit 182 (specifically, an immittance filter) functioning as an immittance conversion unit. On the other hand, when the characteristic changeover switch SWA is turned on, the output unit of the power-receiver resonant circuit 140 and the input unit of the rectifier circuit 200 are connected without the filter circuit 182, that is, bypassed. The characteristic changeover switch SWA is turned off in the normal state, and the power receiver circuit 500 in the normal state is a circuit of the Double-LCC system. Therefore, the output characteristic required by the power receiver circuit 500 is a current source.

[0146] FIG. 15 is a flowchart of the power supply start process executed by the power-receiver controller 231. Steps S1 to S9 are identical to those in the first embodiment, and thus description thereof is omitted.

[0147] In the fourth embodiment, when the determination result in step S4 is negative, that is, when the output characteristic of the power transmitter circuit 400 is the voltage source (in the case of the SS system), the power-receiver controller 231 performs the switching process (step S12). In step S12, the power-receiver controller 231 turns on the characteristic changeover switch SWA. As a result, the filter circuit 182 that is an immittance filter is bypassed, and the number of the immittance conversion units is reduced by one, so that the output characteristic is not changed by the filter circuit 182. Then, the power-receiver controller 231 advances the process to step S5.

[0148] After step S12, when main power transfer (wireless power transfer) is started in step S8, the output characteristic is not converted by the filter circuit 182 in the power receiver circuit 500, and the output characteristic from the power receiver circuit 500 to the high-voltage storage battery 300 can be the current source. As a result, the combination of the power receiver circuit 500 and the power transmitter circuit 400 is appropriate. Therefore, the processing of steps S3, S4, S9 and S12 corresponds to a power-receiver control step executed by the power-receiver control unit 230.

[0149] When the characteristic changeover switch SW is turned off in the normal state, the power receiver circuit 500 is identical to the circuit of the Double-LCC system. In the normal state, since the filter circuit 182 is interposed between the power-receiver resonant circuit 140 and the rectifier circuit 200, harmonics can be reduced.

[0150] Fifth Embodiment 　　　　　　 Hereinafter, the fifth embodiment will be described with reference to the drawings, focusing on differences from the fourth embodiment. In the present embodiment, the power receiver circuit 500 is a circuit illustrated in FIG. 16. In the fifth embodiment, the power receiver circuit 500 serving as a base is a circuit of the SS system.

[0151] The power receiver circuit 500 includes a characteristic changeover switch SWB connected in parallel to each series capacitor 183B.

[0152] When the characteristic changeover switch SWB is turned off, the filter circuit 182, which is a band-pass filter, does not function as an immittance converter. That is, the circuit is a normal band-pass filter. On the other hand, when the characteristic changeover switch SW is turned on, the parallel capacitor 183A is bypassed by the characteristic changeover switch SWB. As a result, the filter circuit 182 is an immittance filter and functions as an immittance converter. As a result, in the power receiver circuit 500, the number of immittance conversion units is increased by one, and the output characteristic is changed.

[0153] The power-receiver controller 231 performs a power supply start process similar to the process of FIG. 15. Specifically, the power-receiver controller 231 turns on or off the characteristic changeover switch SWB (in the drawing, the characteristic changeover switch SW) according to the determination result of whether the combination is appropriate in step S4.

[0154] For example, when it is determined that the power transmitter circuit 400 is the circuit of the SS system illustrated in FIG. 5, that is, when the output characteristic of the power transmitter circuit 400 is the voltage source, the power-receiver controller 231 determines that the combination is appropriate, and turns off the characteristic changeover switch SWB. On the other hand, when it is determined that the power transmitter circuit 400 is the circuit of the Double-LCC system illustrated in FIG. 6, that is, when the output characteristic of the power transmitter circuit 400 is the current source, the power-receiver controller 231 determines that the combination is not appropriate, and turns on the characteristic changeover switch SWB. As a result, the output characteristic is converted by the filter circuit 182, and as a result, the output characteristic of the power receiver circuit 500 (rectifier circuit 200) is a current source when viewed from the high-voltage storage battery 300.

[0155] In addition, according to the present embodiment, since the circuit format can be switched by effectively using the band-pass filter, it is possible to reduce the number of elements or the like added to change the output characteristic.

[0156] Sixth Embodiment 　　　　　　 Hereinafter, the sixth embodiment will be described with reference to the drawings, focusing on differences from the fourth embodiment. In the present embodiment, the power receiver circuit 500 is a circuit illustrated in FIG. 17. In the present embodiment, the power receiver circuit 500 serving as a base is a circuit of the Double-LCC system. In the present embodiment, the capacitor 184B is referred to as a first capacitor 184B.

[0157] The filter circuit 182 includes a second capacitor 184D connected in parallel to the power receiver coil 102 and a characteristic changeover switch SWC. The series connection body of the second capacitor 184D and the characteristic changeover switch SWC connects one of the both ends of each first inductor 184A, the one end being close to the power-receiver resonant circuit 140.

[0158] The power-receiver controller 231 performs a power supply start process similar to the process of FIG. 15. Specifically, the power-receiver controller 231 turns on or off the characteristic changeover switch SWC (in the drawing, the characteristic changeover switch SW) according to the determination result of whether the combination is appropriate in step S4. When the characteristic changeover switch SWC is turned on, the filter circuit 182 functions as a fourth-order filter.

[0159] For example, when it is determined that the power transmitter circuit 400 is the circuit of the Double-LCC system illustrated in FIG. 6, that is, when the output characteristic of the power transmitter circuit 400 is the current source, the power-receiver controller 231 determines that the combination is appropriate, and turns off the characteristic changeover switch SWC. As a result, the power receiver circuit 500 is identical to the circuit of the normal Double-LCC system illustrated in FIG. 6, and power can be appropriately supplied.

[0160] On the other hand, when it is determined that the power transmitter circuit 400 is the circuit of the SS system illustrated in FIG. 5, that is, when the output characteristic of the power transmitter circuit 400 is the voltage source, the power-receiver controller 231 determines that the combination is not appropriate, and turns on the characteristic changeover switch SWC. As a result, the number of immittance conversion units in the power receiver circuit 500 is increased by one. In this case, the output characteristic is not converted by the filter circuit 182. As a result, when viewed from the high-voltage storage battery 300, the output characteristic of the power receiver circuit 500 (rectifier circuit 200) is a current source.

[0161] According to the present embodiment described above, the same effects as those of the fifth embodiment can be obtained.

[0162] Modification of Sixth Embodiment 　　　　　　 The characteristic changeover switch SWD may be connected in series to the first capacitor 184B instead of the second capacitor 184D.

[0163] Seventh Embodiment 　　　　　　 Hereinafter, the seventh embodiment will be described with reference to the drawings, focusing on differences from the sixth embodiment. In the present embodiment, the power receiver circuit 500 is a circuit illustrated in FIG. 18. In the present embodiment, the power receiver circuit 500 serving as a base is a circuit of the Double-LCC system. The electrostatic capacitance of the first capacitor 184B is identical to the electrostatic capacitance of the second capacitor 184D.

[0164] The power receiver circuit 500 includes a characteristic changeover switch SWD. The series connection body of the second capacitor 184D and the characteristic changeover switch SWD connects one of the both ends of each first inductor 184A, the one end being close to the rectifier circuit 200.

[0165] The power-receiver controller 231 performs a power supply start process similar to the process of FIG. 15. Specifically, the power-receiver controller 231 turns on or off the characteristic changeover switch SWD (the characteristic changeover switch SW in the drawing) according to the determination result of whether the combination is appropriate in step S4.

[0166] For example, when it is determined that the power transmitter circuit 400 is the circuit of the Double-LCC system illustrated in FIG. 6, that is, when the output characteristic of the power transmitter circuit 400 is the current source, the power-receiver controller 231 determines that the combination is appropriate, and turns off the characteristic changeover switch SWD. As a result, the power receiver circuit 500 is identical to the circuit of the normal Double-LCC system illustrated in FIG. 6, and power can be appropriately supplied.

[0167] On the other hand, when it is determined that the power transmitter circuit 400 is the circuit of the SS system illustrated in FIG. 5, that is, when the output characteristic of the power transmitter circuit 400 is the voltage source, the power-receiver controller 231 determines that the combination is not appropriate, and turns on the characteristic changeover switch SWD. As a result, the number of immittance conversion units in the power receiver circuit 500 is increased by one. In this case, the output characteristic is not converted by the filter circuit 182. As a result, when viewed from the high-voltage storage battery 300, the output characteristic of the power receiver circuit 500 (rectifier circuit 200) is a current source.

[0168] According to the present embodiment described above, the same effects as those of the fifth embodiment can be obtained.

[0169] Eighth Embodiment 　　　　　　 Hereinafter, the eighth embodiment will be described with reference to the drawings, focusing on differences from the above embodiments. In the present embodiment, as illustrated in FIG. 19, the power receiver circuit 500 is configured to be switchable between an S system (series system) and a P system (parallel system).

[0170] The power-receiver resonant circuit 140 includes a parallel capacitor 142, a first switch SW1, and a second switch SW2. A series connection body of the parallel capacitor 142 and the first switch SW1 is connected in parallel to the power receiver coil 102. The second switch SW2 is connected in parallel to each series capacitor 141.

[0171] The power-receiver controller 231 performs a power supply start process similar to the process of FIG. 15. Specifically, the power-receiver controller 231 turns on or off the first switch SW1 and the second switch SW2 (simply referred to as SW in the drawing) according to the determination result of whether the combination is appropriate in step S4.

[0172] For example, when it is determined that the power transmitter circuit 400 is the circuit of the SS system illustrated in FIG. 5, that is, when the output characteristic of the power transmitter circuit 400 is the voltage source, the power-receiver controller 231 determines that the combination is appropriate, and turns off the first switch SW1 and the second switch SW2. When the first switch SW1 and the second switch SW2 are turned off, the power-receiver resonant circuit 140 is set to the S system in which each series capacitor 23 is connected in series to the power receiver coil 102. As a result, the power receiver circuit 500 is identical to the circuit of the normal SS system illustrated in FIG. 5, and power can be appropriately supplied.

[0173] On the other hand, when it is determined that the power transmitter circuit 400 is the circuit of the Double-LCC system illustrated in FIG. 6, that is, when the output characteristic of the power transmitter circuit 400 is the current source, the power-receiver controller 231 determines that the combination is not appropriate, and turns on the first switch SW1 and the second switch SW2. When the first switch SW1 and the second switch SW2 are turned on, the power-receiver resonant circuit 140 is set to the P system in which the parallel capacitor 142 is connected in parallel to the power receiver coil 102. By being set to the P system, the power-receiver resonant circuit 140 changes the output characteristic. As a result, the output characteristic from the power receiver circuit 500 is a current source, and power can be appropriately supplied.

[0174] Ninth Embodiment 　　　　　　 Hereinafter, the ninth embodiment will be described with reference to the drawings, focusing on differences from the eighth embodiment. Also in the present embodiment, as illustrated in FIG. 20, the output characteristic can be switched by providing a resonant coil 25 that resonates with the power receiver coil 102.

[0175] The power receiver circuit 500 includes a resonant coil 25 magnetically coupled to the power receiver coil 102, a sub-capacitor 26, and a third switch SW3. A series connection body of the sub-capacitor 26 and the third switch SW3 is connected in parallel to the resonant coil 25.

[0176] The power-receiver controller 231 performs the power supply process similar to the process of FIG. 15. Specifically, the power-receiver controller 231 turns on or off the third switch SW3 (referred to as SW in the drawing) according to the determination result of whether the combination is appropriate in step S4.

[0177] For example, when it is determined that the power transmitter circuit 400 is the circuit of the SS system illustrated in FIG. 5, that is, when the output characteristic of the power transmitter circuit 400 is the voltage source, the power-receiver controller 231 determines that the combination is appropriate, and turns off the third switch SW3. When the third switch SW3 is turned off, the closed circuit including the resonant coil 25 and the sub-capacitor 26 is cut off. As a result, the power receiver circuit 500 is identical to the power receiver circuit 500 of the SS system illustrated in FIG. 5, and power can be appropriately supplied.

[0178] On the other hand, when it is determined that the power transmitter circuit 400 is the circuit of the Double-LCC system illustrated in FIG. 6, that is, when the output characteristic of the power transmitter circuit 400 is the current source, the power-receiver controller 231 determines that the combination is not appropriate, and turns on the third switch SW3. When the third switch SW3 is turned on, a closed circuit including the resonant coil 25 and the sub-capacitor 26 is energized to resonate with the power receiver coil 102. As a result, the output characteristic is not changed between the power transmitter coil 22 and the power receiver coil 102. Therefore, the output characteristic from the power receiver circuit 500 is a current source, and power can be appropriately supplied.

[0179] Other Embodiments 　　　　　　 Each of the above embodiments may be modified as follows.

[0180] In the power supply start process (FIGS. 8, 12, 13, and 15) of each of the above embodiments, when the determination result of step S8 is negative, the wireless power transfer is stopped, but the wireless power transfer (main power transfer) may be executed assuming that the output characteristic, of the power transmitter circuit 400, identified by the power waveform of the test radio wave TW is correct.

[0181] More specifically, when the determination result in step S8 is negative and the output characteristic, of the power transmitter circuit 400, identified by the power waveform of the test radio wave TW matches the output characteristic of the power transmitter circuit 400 required by the power receiver circuit 500 in the normal state (that is, before the process in steps S10, S11, and S12), the power receiver circuit 500 in the normal state performs the process in step S9.

[0182] On the other hand, when the output characteristic, of the power transmitter circuit 400, identified by the power waveform of the test radio wave TW does not match the output characteristic of the power transmitter circuit 400 required by the power receiver circuit 500 in the normal state, the output characteristic of the power receiver circuit 500 is changed as in each of the above embodiments, and the process of step S9 is performed.

[0183] When the output characteristic of the power receiver circuit 500 is changed, as a premise, the circuit configuration of the power receiver circuit 500 described in the second embodiment to the ninth embodiment is included, and the power-receiver control unit 230 changes the control of the wireless power transfer or the circuit configuration of the power receiver circuit 500 as in the second to ninth embodiments.

[0184] In step S8 of the power supply start process (FIGS. 8, 12, 13, and 15) of each of the above embodiments, the output characteristic of the power transmitter circuit 400 is determined based on the power waveform of the test radio wave TW, and it is determined whether the output characteristic matches the output characteristic included in the power-transmitter information. As a modification, the output characteristic of the power transmitter circuit 400 may be determined based on the power waveform of the test radio wave TW, and it may be determined whether the determined output characteristic matches the output characteristic required by the power receiver circuit 500, that is, whether the power receiver circuit 500 is compatible with the determined output characteristic.

[0185] In this modification, it is not necessary to acquire the power-transmitter information. In addition, in the case of this modification, it is not necessary to identify the output characteristic included in the power-transmitter information, and it is not necessary to determine whether the power receiver circuit 500 is compatible with the output characteristic included in the power-transmitter information.

[0186] When the output characteristic based on the test radio wave TW does not match the output characteristic required by the power receiver circuit 500, the output characteristic of the power receiver circuit 500 may be changed as in each of the above embodiments.

[0187] When the output characteristic of the power receiver circuit 500 is changed, as a premise, the circuit configuration of the power receiver circuit 500 described in the second embodiment to the ninth embodiment is included, and the power-receiver control unit 230 changes the control of the wireless power transfer or the circuit configuration of the power receiver circuit 500 as in the second to ninth embodiments.

[0188] In step S3 of the power supply start process (FIGS. 8, 12, 13, and 15) of each embodiment, when the first power-transmitter information and the second power-transmitter information are not consistent with each other, the second power-transmitter information, that is, the power-transmitter information acquired by the narrow-area wireless communication may be regarded as correct information, and the process in and after step S4 may be performed.

[0189] That is, assuming that the second power-transmitter information acquired at a shorter distance and more immediately before is correct, the power-receiver control unit 230 may change one of control related to the wireless power transfer, the power receiver circuit 500, and determination of whether the wireless power transfer is possible. As a result, it is possible to more appropriately perform power supply or appropriately restrict power supply.

[0190] The wireless power transfer system may have a second function of performing wireless power transfer from the vehicle-side device to the ground-side device in addition to a first function of performing wireless power transfer from the ground-side device to the vehicle-side device. In this case, the in-vehicle power receiver 100 has a power transmitting function in addition to a power receiving function. Further, the ground power transmitter 20 has a power receiving function in addition to a power transmitting function. Hereinafter, the second function will be described with reference to FIG. 3 as an example.

[0191] The power-receiver controller 231 applies a high-frequency AC voltage to the power receiver coil 102 by switching control of the rectifier circuit 200. As a result, a high-frequency current flows through the power receiver coil 102, and a magnetic field for power transmitter is generated in the power receiver coil 102.

[0192] When the magnetic field generated in the power receiver coil 102 interlinks with the power transmitter coil 22, a high-frequency current that fluctuates at the frequency of the high-frequency current flowing in the power receiver coil 102 flows through the power transmitter coil 22. The high-frequency current flowing through the power transmitter coil 22 is supplied to the AC power supply 15 via the power-transmitter resonant circuit 30, the filter circuit 52, the inverter 60, and the PFC circuit 61. In this case, the power-transmitter controller 71 performs switching control of the inverter 60 and the PFC circuit 61.

[0193] Note that, in the wireless power transfer system having the second function, for example, the power transmitter 20 may include a transmitter that supplies the power supply request signal to the power-transmitter communication coil 40. In addition, the power receiver 100 may include a receiver that receives the power supply request signal received by the power-receiver communication coil 170 and inputs the power supply request signal to the power-receiver controller 231.

[0194] The wireless power transfer system may have a function of performing wireless power transfer from the vehicle-side device to the ground-side device instead of the function of performing wireless power transfer from the ground-side device to the vehicle-side device.

[0195] The power-receiver communication antenna and the power-transmitter communication antenna are not limited to the communication coil, and various antennas can be used. For example, the communication antenna is a dipole antenna or a monopole antenna.

[0196] The method of wireless power transfer by the power transmitting antenna and the power receiving antenna is not limited to the magnetic field resonance method, and may be an electric field coupling method. In this case, a power transmitting antenna and a power receiving antenna that are different from the coil and are of an electric field coupling method may be used.

[0197] The vehicle identification information used in the process of each of the above embodiments is not limited to the vehicle ID information, and may be, for example, a token or credit card information of a vehicle user.

[0198] The vehicle on which the power receiver 100 is mounted is not limited to a vehicle traveling on the road RS, and may be, for example, an AGV (automated guided vehicle) or a traveling robot. In this case, the power-transmitter coil unit 21 is not buried in the road RS, but may be installed at a sidewalk, a parking lot, or a route on which the AGV travels, adjacent to the road RS.

[0199] The control section and the method thereof described in the present disclosure may be realized by a dedicated computer provided by configuring a processor and a memory programmed to execute one or a plurality of functions embodied by a computer program. Alternatively, the control section and the method thereof described in the present disclosure may be realized by a dedicated computer provided by configuring a processor by one or more dedicated hardware logic circuits. Alternatively, the control section and the method thereof described in the present disclosure may be realized by one or more dedicated computers configured by a combination of a processor and a memory programmed to execute one or a plurality of functions and a processor configured by one or more hardware logic circuits. Furthermore, the computer program may be stored in a computer-readable non-transitory tangible recording medium as an instruction executed by a computer.

Claims

1. A power receiver for a wireless power transfer system (10) including a vehicle-side device and a ground-side device, one of the vehicle-side device and the ground-side device being a power transmitter (20) having a power transmitting antenna (22) and a power transmitter circuit (400), another of the vehicle-side device and the ground-side device being the power receiver having a power receiving antenna (102) and a power receiver circuit (500), the power transmitting antenna being configured to be energized to perform wireless power transfer to the power receiving antenna, 　　　　　　 the power transmitter being configured to transmit a test radio wave having a power waveform that includes one or multiple predetermined cycles, before performing the wireless power transfer, 　　　　　　 the waveform of the test radio wave corresponding to an output characteristic of the power transmitter circuit, 　　　　　　 the power receiver comprising: 　　　　　　 a power transmission determination unit (230) configured to determine whether power has been normally transmitted via the test radio wave and determine the output characteristic of the power transmitter circuit based on the waveform of the test radio wave; and 　　　　　　 a power-receiver control unit (230) configured to change, based on the output characteristic identified by the power transmission determination unit, at least one of 　　　　　　　　　　　　　 control related to the wireless power transfer, 　　　　　　　　　　　　　 a configuration of the power receiver circuit, and 　　　　　　　　　　　　　 determination of whether the wireless power transfer is possible.

2. The power receiver according to claim 1, wherein 　　　　　　 the power-receiver control unit is configured to 　　　　　　　　　　　　　 check compatibility of the power receiver circuit with the output characteristic identified by the power transmission determination unit, and 　　　　　　　　　　　　　 determine whether the wireless power transfer is possible.

3. The power receiver according to claim 1 or 2, further comprising 　　　　　　 an information acquisition unit (240, 332) configured to acquire power-transmitter information including at least the output characteristic of the power transmitter circuit before the wireless power transfer is performed, wherein 　　　　　　 the power-receiver control unit is configured to start power supply to a power supply target device when determining that the output characteristic identified based on the power-transmitter information acquired by the information acquisition unit is identical to the output characteristic determined by the power transmission determination unit.

4. The power receiver according to any one of claims 1 to 3, further comprising: 　　　　　　 a power-receiver communication unit (240) configured to transmit a power supply request signal for a power supply request to the power transmitter, wherein 　　　　　　 the power transmitter is configured to transmit the test radio wave having the power waveform that includes one or multiple predetermined cycles after receiving the power supply request signal and before performing the wireless power transfer.

5. The power receiver according to claim 4, wherein 　　　　　　 the power-receiver control unit is configured to 　　　　　　　　　　　　　 prevent power supply from the power receiving antenna to a power supply target device until the waveform of the test radio wave is determined by the power transmission determination unit after receiving the power supply request signal, and 　　　　　　　　　　　　　 start the power supply from the power receiving antenna to the power supply target device after the waveform of the test radio wave is determined by the power transmission determination unit.

6. The power receiver according to any one of claims 1 to 5, wherein 　　　　　　 the test radio wave varies in at least one of amplitude, frequency, wavelength, number of waves, amount of current, or transmission period depending on the output characteristic.

7. A power transmitter (20) for a wireless power transfer system (10) including a vehicle-side device and a ground-side device, one of the vehicle-side device and the ground-side device being the power transmitter having a power transmitting antenna (22) and a power transmitter circuit (400), another of the vehicle-side device and the ground-side device being a power receiver (100) having a power receiving antenna (102) and a power receiver circuit (500), the power transmitting antenna being configured to be energized to perform wireless power transfer to the power receiving antenna, the power transmitter (20) comprising: 　　　　　　 a power-transmitter control unit (70) configured to transmit a test radio wave having a power waveform that includes one or multiple predetermined cycles, before performing the wireless power transfer, wherein 　　　　　　 the waveform of the test radio wave corresponds to an output characteristic of the power transmitter circuit.

8. A wireless power transfer system (10) comprising a vehicle-side device and a ground-side device, wherein 　　　　　　 one of the vehicle-side device and the ground-side device is a power transmitter (20) having a power transmitting antenna (22) and a power transmitter circuit (400), 　　　　　　 another of the vehicle-side device and the ground-side device is a power receiver (100) having a power receiving antenna (102) and a power receiver circuit (500), 　　　　　　 the power transmitting antenna is configured to be energized to perform wireless power transfer to the power receiving antenna, 　　　　　　 the power transmitter includes a power-transmitter control unit (70) configured to transmit a test radio wave having a power waveform that includes one or multiple predetermined cycles, before performing the wireless power transfer, wherein 　　　　　　 the waveform of the test radio wave corresponds to an output characteristic of the power transmitter circuit, and 　　　　　　 the power receiver includes 　　　　　　 a power transmission determination unit (230) configured to determine whether power has been normally transmitted via the test radio wave and determine the output characteristic of the power transmitter circuit based on the waveform of the test radio wave, and 　　　　　　 a power-receiver control unit (230) configured to change, based on the output characteristic identified by the power transmission determination unit, at least one of 　　　　　　 　　　　　　 control related to the wireless power transfer, 　　　　　　　　　　　　　 a configuration of the power receiver circuit, and 　　　　　　　　　　　　　 determination of whether the wireless power transfer is possible.

9. A program for a power receiver of a wireless power transfer system (10), the wireless power transfer system including a vehicle-side device and a ground-side device, one of the vehicle-side device and the ground-side device being a power transmitter (20) having a power transmitting antenna (22) and a power transmitter circuit (400), another of the vehicle-side device and the ground-side device being the power receiver having a power receiving antenna (102) and a power receiver circuit (500), the power transmitting antenna being configured to be energized to perform wireless power transfer to the power receiving antenna, 　　　　　　 the power transmitter being configured to transmit a test radio wave having a power waveform that includes one or multiple predetermined cycles, before performing the wireless power transfer, 　　　　　　 the waveform of the test radio wave corresponding to an output characteristic of the power transmitter circuit, 　　　　　　 the program causing the power receiver to execute: 　　　　　　 a power transmission determination step of determining whether power has been normally transmitted via the test radio wave, and determining the output characteristic of the power transmitter circuit based on the waveform of the test radio wave; and 　　　　　　 a power-receiver control step of changing, based on the output characteristic identified by the power transmission determination step, at least one of 　　　　　　　　　　　　　 control related to the wireless power transfer, 　　　　　　　　　　　　　 a configuration of the power receiver circuit, and 　　　　　　　　　　　　　 determination of whether the wireless power transfer is possible.

10. A control method performed by a power receiver of a wireless power transfer system (10), the wireless power transfer system including a vehicle-side device and a ground-side device, one of the vehicle-side device and the ground-side device being a power transmitter (20) having a power transmitting antenna (22) and a power transmitter circuit (400), another of the vehicle-side device and the ground-side device being the power receiver having a power receiving antenna (102) and a power receiver circuit (500), the power transmitting antenna being configured to be energized to perform wireless power transfer to the power receiving antenna, 　　　　　　 the power transmitter being configured to transmit a test radio wave having a power waveform that includes one or multiple predetermined cycles, before performing the wireless power transfer, 　　　　　　 the waveform of the test radio wave corresponding to an output characteristic of the power transmitter circuit, 　　　　　　 the control method comprising: 　　　　　　 a power transmission determination step of determining whether power has been normally transmitted via the test radio wave, and determining the output characteristic of the power transmitter circuit based on the waveform of the test radio wave; and 　　　　　　 a power-receiver control step of changing, based on the output characteristic identified by the power transmission determination step, at least one of 　　　　　　　　　　　　　 control related to the wireless power transfer, 　　　　　　　　　　　　　 a configuration of the power receiver circuit, and 　　　　　　　　　　　　　 determination of whether the wireless power transfer is possible.

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