Power receiver, 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 the power receiver coil (102). When detecting an abnormality during the wireless power transfer, a power-receiver control unit (230) of the power receiver (100) protects the power receiver circuit (500) by using a protection unit. The power-receiver control unit (230) includes a power-receiver communication device (240) that acquires power-transmitter information including at least an output characteristic of the power transmitter circuit (400) via narrow-area wireless communication, and changes a protection mode of the protection unit according to the output characteristic.

Description

POWER RECEIVER, PROGRAM, AND CONTROL METHODCross Reference

[0001] This application is based on Japanese Patent Application No. 2025-019565 filed on February 7, 2025, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a power receiver, 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] It is common that the power receiver circuit of the vehicle includes a protection circuit for protecting the power receiver circuit at the time of abnormality.

[0006] However, the ground-side coils have various circuit topologies, and there are a power transmitter circuit having an output characteristic close to a voltage source and a power transmitter circuit having an output characteristic close to a current source. When the protection circuit is not adapted to the output characteristic of the power transmitter circuit, appropriate circuit protection cannot be performed, and there is a possibility that a large current flows during circuit protection or a voltage exceeding the withstand voltage of the circuit element is applied.

[0007] It is a main object of the present disclosure to provide a power receiver, a program, and a control method, which are capable of suppressing occurrence of disadvantage due to a difference in output characteristics.

[0008] 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 receiver includes an abnormality detection unit configured to detect an abnormality during the wireless power transfer, a protection unit configured to execute protection of the power receiver circuit when the abnormality is detected by the abnormality detection unit, an information acquisition unit configured to acquire power-transmitter information including at least an output characteristic of the power transmitter circuit, and a power-receiver control unit configured to change a protection mode of the protection unit according to the output characteristic acquired by the information acquisition unit.

[0009] According to the above configuration, since the protection mode is changed according to the output characteristic of the power transmitter circuit, the occurrence of the above-described disadvantage can be suppressed.

[0010] 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 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 program causes the power receiver to execute: an abnormality detection step of detecting an abnormality during the wireless power transfer; a protection step of executing protection of the power receiver circuit by using a protection unit when the abnormality is detected in the abnormality detection step; an information acquisition step of acquiring power-transmitter information including at least an output characteristic of the power transmitter circuit; and a change step of changing a protection mode of the protection unit according to the output characteristic acquired in the information acquisition step.

[0011] According to the above configuration, since the protection mode is changed according to the output characteristic of the power transmitter circuit, the occurrence of the above-described disadvantage can be suppressed.

[0012] 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 control method includes: an abnormality detection step of detecting an abnormality during the wireless power transfer; a protection step of executing protection of the power receiver circuit by using a protection unit when an abnormality is detected in the abnormality detection step; an information acquisition step of acquiring power-transmitter information including at least an output characteristic of the power transmitter circuit; and a change step of changing a protection mode of the protection unit according to the output characteristic acquired in the information acquisition step.

[0013] According to the above configuration, since the protection mode is changed according to the output characteristic of the power transmitter circuit, the occurrence of the above-described disadvantage can be suppressed.

[0014] 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 topology.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 topology.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 view illustrating the protection unit.FIG. 10 is a flowchart of the protection process.FIG. 11 is a block diagram of the information acquisition unit according to the modification.FIG. 12 is a flowchart of the power supply start process according to the second embodiment.FIG. 13 is a view illustrating the protection unit according to the third embodiment.FIG. 14 is a flowchart of the protection process according to the third embodiment.FIG. 15 is a view illustrating the protection unit according to the fourth embodiment.FIG. 16 is a flowchart of the protection process according to the fourth embodiment.FIG. 17 is a diagram illustrating a relationship between a drive frequency and a resonance frequency.FIG. 18 is a configuration diagram of the power receiver circuit according to the fifth embodiment.FIG. 19 is a flowchart of the power supply start process according to the fifth embodiment.FIG. 20 is a configuration diagram of the power receiver circuit according to the sixth embodiment.FIG. 21 is a flowchart of the power supply start process according to the sixth embodiment.FIG. 22 is a configuration diagram of the power receiver circuit according to the seventh embodiment.FIG. 23 is a configuration diagram of the power receiver circuit according to the eighth embodiment.FIG. 24 is a configuration diagram of the power receiver circuit according to the ninth embodiment.FIG. 25 is a configuration diagram of the power receiver circuit according to the tenth embodiment.FIG. 26 is a configuration diagram of the power receiver circuit according to the eleventh embodiment.

[0015] 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. For a corresponding portion and / or an associated portion, reference may be made to descriptions of other embodiments.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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. In the present embodiment, the inverter 60, the filter circuit 52, and the power-transmitter resonant circuit 30 constitute a power transmitter circuit 400.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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). 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. In addition, the rectifier circuit 200 of the present embodiment is a full-bridge circuit including a semiconductor switching element.

[0028] 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.

[0029] 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. In the present embodiment, the high-voltage storage battery 300 corresponds to a “power supply target device”.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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 (power supply target device 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.

[0056] 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 addition, the output characteristic of the power receiver coil 102 between the power receiver coil 102 and the power receiver circuit 500 at the time of wireless power transfer may be obtained by measuring a current and a voltage flowing from the power receiver coil 102 to the power receiver circuit 500 (in the present embodiment, the power-receiver resonant circuit 140). 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.

[0057] 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.

[0058] FIG. 5 illustrates the wireless power transfer system 10 of the SS topology. The power transmitter circuit 400 of this topology 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.

[0059] The power receiver circuit 500 of the wireless power transfer system 10 of the SS topology 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.

[0060] In the wireless power transfer system 10 of the SS topology, 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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 power supply target device 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 power supply target device (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.

[0065] 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.

[0066] FIG. 6 illustrates the wireless power transfer system 10 of the Double-LCC topology. The power transmitter circuit 400 of this topology 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.

[0067] The power receiver circuit 500 of the wireless power transfer system 10 of the Double-LCC topology 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.

[0068] In the wireless power transfer system 10 of the Double-LCC topology, 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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 topology (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).

[0075] 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 a disadvantage. 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.

[0076] In order to cope with such a disadvantage, the power-receiver control unit 230 acquires the power-transmitter information about the power transmitter 20 before the wireless power transfer is performed, and changes the control of the power receiver circuit 500 based on the output characteristic of the power transmitter circuit 400 included in the acquired power-transmitter information. Hereinafter, a flow until the power-receiver control unit 230 checks the power-transmitter information and starts 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.

[0077] 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 and a second 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.

[0078] The power-transmitter information includes at least information about an output characteristic of the power transmitter circuit 400. The information about the output characteristic of the power transmitter circuit 400 may be information directly indicating the output characteristic of the power transmitter circuit 400, such as a voltage source, or may be information indirectly indicating a model number (such as an identification number or a serial number) of the power transmitter 20 if the output characteristic of the power transmitter circuit 400 and the model number are stored in association with each other. 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.

[0079] 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.

[0080] 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.

[0081] 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 supply) is defined.

[0082] The tracking in the present embodiment is to transmit experimentally predetermined power (test radio wave) before starting power supply to the power supply target device (before starting main power supply), and to check whether the power is appropriately transmitted from the power transmitter coil 22 to the power receiver coil 102.

[0083] 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.

[0084] 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 corresponds to an information acquisition unit and a first information acquisition unit. The processing of steps S1 and S2 corresponds to an information acquisition step.

[0085] The second power-transmitter information includes at least information about an output characteristic of the power transmitter circuit 400. Furthermore, the second power-transmitter information may include, in addition to the information about the output characteristics, antenna information about the power transmitter coil 22, communication standard information about a communication standard, power information about 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.

[0086] 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.

[0087] 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.

[0088] 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. In the initial state (normal state), 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.

[0089] 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.

[0090] 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. The power-receiver control unit 230 receives the power transmitted by the tracking by the power receiver circuit 500 (step S6).

[0091] 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 transmitted by the tracking is a predetermined test radio wave. Specifically, it is determined whether the waveform (amplitude, frequency, and the like) of the test radio wave is predetermined.

[0092] When the determination result is negative, the power-receiver control unit 230 does not start the wireless power transfer (main power supply), 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).

[0093] On the other hand, when the determination result of step S7 is affirmative, the power-receiver control unit 230 starts wireless power transfer (main power supply) (step S8). Specifically, the power-transmitter controller 71 starts the main power supply a predetermined time after the tracking was performed. On the other hand, after the start of the main power supply, the power-receiver control unit 230 supplies power to the high-voltage storage battery 300 serving as the power supply target device and charges the high-voltage storage battery 300.

[0094] The power-receiver control unit 230 performs short-circuit control of the power receiver coil 102 by the rectifier circuit 200 until main power supply is started, restricts power supply to the high-voltage storage battery 300, and after the main power supply is started, cancels the short-circuit control, performs rectification by the rectifier circuit 200, and starts power supply to the high-voltage storage battery 300.

[0095] On the other hand, when the determination result of step S4 is negative, the power-receiver control unit 230 performs the switching process for changing the output characteristic (step S9). In step S9, the power-receiver control unit 230 determines to change the control of the rectifier circuit 200, and sets the change. Specifically, the power-receiver controller 231 determines (sets) 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.

[0096] 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.

[0097] Then, the power-receiver control unit 230 advances the process to step S5. After the process of step S9, when main power supply (wireless power transfer) is started in step S8, the power-receiver control unit 230 changes the switching control of the rectifier circuit 200 as determined in step S9 in order to change the output characteristic. Specifically, the power-receiver control unit 230 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.

[0098] Incidentally, the power receiver circuit 500 is usually provided with a protection unit for protecting the power receiver circuit 500 when an abnormality occurs. An example of the protection unit includes a short-circuit switch that short-circuits the power receiver coil 102 to restrict power supply to the high-voltage storage battery 300. According to this short-circuit switch, when the output characteristic of the power transmitter circuit 400 is the voltage source (that is, the case of the SS topology), application of a large voltage by short-circuit control can be suppressed.

[0099] However, when short-circuit control is performed in the power receiver circuit 500 configured to be able to receive power even when the output characteristic of the power transmitter circuit 400 is a current source as in the present embodiment, there is a possibility that a large current flows. That is, since the input to the power receiver circuit 500 serves as a voltage source, there is a possibility that a large current flows when the short circuit control is performed.

[0100] Therefore, in the present embodiment, the protection unit capable of appropriately protecting the power receiver circuit 500 at the time of abnormality is provided regardless of whether the output characteristic of the power transmitter circuit 400 is the current source or the voltage source. Details will be described below.

[0101] First, the configuration of the protection unit of the present embodiment will be described. As illustrated in FIG. 9, a short-circuit switch SW11 is provided so as to connect both ends of the power receiver coil 102. When the short-circuit switch SW11 is turned on, the power receiver coil 102 is short-circuited. As illustrated in FIG. 9, an open switch SW12 is provided on an electric path between the power receiver coil 102 and the power-receiver resonant circuit 140. When the open switch SW12 is turned on, electric current flows between the power receiver coil 102 and the power-receiver resonant circuit 140, and when turned on, electric current is cut off between the power receiver coil 102 and the power-receiver resonant circuit 140. The open switch SW12 is in the closed state in the normal state, and is in the closed state during the wireless power transfer.

[0102] In the present embodiment, the short-circuit switch SW11 and the open switch SW12 constitute a protection unit 501. The short-circuit switch SW11 and the open switch SW12 are configured to be switched between on and off states by an instruction from the power-receiver control unit 230, more specifically, the power-receiver controller 231.

[0103] Next, a flow of the protection process at the time of abnormality detection will be described with reference to FIG. 10. The protection process is performed by the power-receiver control unit 230. The power-receiver control unit 230 determines whether an abnormality has occurred in the power receiver circuit 500 (step S101). As a result, the power-receiver control unit 230 corresponds to an abnormality determination unit, and the processing of step S101 corresponds to an abnormality determination step. The method of determining abnormality of the power receiver circuit 500 may be a known method, and for example, an abnormality is detected based on whether a detection value from a current sensor that detects a current flowing through the power receiver circuit 500 is an abnormal value. For example, the abnormality is detected based on whether the detection value from a voltage sensor that detects a voltage applied from the power receiver circuit 500 to high-voltage storage battery 300 is an abnormal value. For example, the abnormality is detected based on whether the detection value from the temperature sensor that detects the temperature of the power receiver circuit 500 is an abnormal value. Other abnormality detection methods may be used, or these methods may be combined. In the present embodiment, the power-receiver control unit 230 corresponds to an abnormality detection unit.

[0104] When the determination result of step S101 is negative, the power-receiver control unit 230 ends the protection process. On the other hand, when the determination result of step S101 is affirmative, the power-receiver control unit 230 checks (determines) the characteristic of the protection unit 501 (step S102). The characteristic of the protection unit 501 is a characteristic of power input to the protection unit 501, and in the present embodiment, since the protection unit 501 is provided between the power receiver coil 102 and the power receiver circuit 500, the characteristic is equal to the output characteristic of the power receiver coil 102. The output characteristic of the power receiver coil 102 can be determined from the output characteristic of the power transmitter circuit 400 as described above. The output characteristic of the power transmitter circuit 400 is confirmed (determined) by, for example, information about the output characteristic included in the power-transmitter information for which the consistency is confirmed in step S3. Therefore, in the present embodiment, when the output characteristic of the power transmitter circuit 400 checked from the power-transmitter information is the current source, it is determined that the characteristic of the protection unit 501 is the voltage source, and when the output characteristic of the power transmitter circuit 400 checked from the power-transmitter information is the voltage source, it is determined that the characteristic of the protection unit 501 is the current source.

[0105] Next, the power-receiver control unit 230 determines whether the characteristic of the protection unit 501 is a current source (step S103). That is, it is determined whether the power transmitter circuit 400 is a circuit of the SS topology (see FIG. 5). As described above, since the output characteristic is converted when power is transmitted from the power transmitter coil 22 to the power receiver coil 102, in step S103, it is determined whether the output characteristic (characteristic of the protection unit 501) of the power receiver coil 102 is a current source when viewed from the power receiver circuit 500.

[0106] When the determination result is affirmative, the power-receiver control unit 230 performs the short-circuit control to turn on the short-circuit switch SW11 (step S104). That is, the power receiver circuit 500 is protected in the short-circuit protection mode.

[0107] On the other hand, when the determination result in step S103 is affirmative, that is, when the power transmitter circuit 400 is a circuit of the Double-LCC topology (circuit in FIG. 6), and the output characteristic (characteristic of protection unit 501) of the power receiver coil 102 is the voltage source when viewed from the power receiver circuit 500, the power-receiver control unit 230 performs the opening control of turning off the short-circuit switch SW11 and turning on the open switch SW12 (step S104). That is, the power receiver circuit 500 is protected in the open protection mode. The processing of steps S102 and S103 corresponds to a change step, and the processing of steps S104 and S105 corresponds to a protection step.

[0108] According to the first embodiment, the following effects are obtained.

[0109] The power-receiver control unit 230 changes the protection mode of the protection unit 501 at the time of abnormality 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. This makes it possible to prevent disadvantage due to a difference in output characteristic at the time of abnormality.

[0110] 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, preparation such as changing the protection mode can be performed in advance.

[0111] 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, the protection mode can be more appropriately determined, and abnormality can be reliably prevented.

[0112] The power-receiver control unit 230 changes the control related to the wireless power transfer 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 control related to the wireless power transfer is changed so as to switch the output characteristic of the power receiver circuit 500.

[0113] Specifically, the power-receiver control unit 230 changes the output characteristic of the power receiver circuit 500 so that the output characteristic is closer to the voltage source characteristic or the current source characteristic than before the change. In the present embodiment, the power-receiver control unit 230 switches the output characteristic of the power receiver circuit 500 by controlling the rectifier circuit 200 (rectifier) so that the output characteristic from the power receiver circuit 500 to the high-voltage storage battery 300 is close to the voltage source characteristic or the current source characteristic. As a result, power supply can be appropriately performed regardless of the output characteristic of the power transmitter circuit 400. In addition, it is sufficient to change the control of the rectifier circuit 200, and it is not necessary to provide a special circuit configuration.

[0114] 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 the control related to the wireless power transfer depending on the presence or absence of compatibility. As a result, when the power receiver circuit 500 is not compatible, it is possible to prevent failure.

[0115] The power-receiver control unit 230 changes the control based on the power-transmitter information before transmitting the power supply request signal COMM. Specifically, before the tracking, the process of step S9 can be performed to change the control related to the wireless power transfer. As a result, it is possible to reliably prevent the power transfer from being erroneously started from the power transmitter 20, and it is possible to appropriately supply power.

[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. In step S4 of the power supply start process of the above embodiment, 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. As another example, the output characteristic of the power receiver coil 102 during the wireless power transfer may be determined from the information about the output characteristic of the power transmitter circuit 400, and it may be determined whether the output characteristic of the power receiver coil 102 matches the output characteristic of the power receiver coil 102 required by the power receiver circuit 500. The output characteristic of the power receiver coil 102 can be determined from the output characteristic of the power transmitter circuit 400 and the configuration of the power receiver coil 102 in the power receiver 100. For example, in the case of the circuit configuration illustrated in FIGS. 5 and 6, an inversion (current source to voltage source or voltage source to current source) of the output characteristic of the power transmitter circuit 400 corresponds to the output characteristic of the power receiver coil 102. Therefore, the power-receiver control unit 230 may invert the output characteristic of the power transmitter circuit 400 included in the received power-transmitter information.

[0118] In addition, the output characteristic of the power receiver coil 102 may be measured and stored in advance for each model of the power transmitter 20, and the power-receiver control unit 230 may read and identify the output characteristic of the power receiver coil 102 from the model information included in the acquired power-transmitter information. In this case, the model information corresponds to information related to the output characteristic of the power transmitter circuit 400.

[0119] In addition, whether the power transmitter 20 and its own power receiver 100 are an appropriate combination may be directly determined. For example, a list of model information or the like indicating the model of the power transmitter 20 that can appropriately receive power without change (initial state) may be stored in advance, and the determination may be made based on whether the model information indicated in the acquired power-transmitter information is included in the list.

[0120] In the above embodiment, the short-circuit control is performed by the short-circuit switch SW11 at the time of abnormality detection, but the short-circuit control may be performed by turning off the switches S11H and S12H or the switches S11L and S122L of the rectifier circuit 200. Therefore, the rectifier is a switching rectifier including multiple switching elements S11H, S12H, S11L, S12L, and one or some of the switching elements S11H, S12H, S11L, S12L constituting the rectifier may be used as the short-circuit switch. 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. In the above embodiment, the consistency between the first power-transmitter information and the second power-transmitter information is determined, but the protection mode may be changed based on either of the power-transmitter information without determining the consistency.

[0121] In the above embodiment, when content of the first power-transmitter information and content of the second power-transmitter information are inconsistent, the following process may be performed based on the second power-transmitter information (information acquired by narrow-area wireless communication). For example, the control may be changed based on the second power-transmitter information, and the protection mode of the protection unit 501 at the time of abnormality may be changed. Therefore, when the power-receiver control unit determines that the content of the first power-transmitter information acquired by the second information acquisition unit (e.g., communication unit 332 capable of executing wide-area wireless communication) and the content of the second power-transmitter information acquired by the first information acquisition unit (e.g., power-receiver communication device 240 capable of executing narrow-area wireless communication) are not consistent, the power-receiver control unit may be configured to change the protection mode of the protection unit according to the output characteristic included in the second power-transmitter information acquired by the first information acquisition unit without using the first power-transmitter information acquired by the second information acquisition unit.

[0122] In addition, in general, on the same road, the power transmitters 20 are also often of the same type, and the output characteristics are also often the same. Therefore, in the case of the inconsistency, when multiple pieces of the power-transmitter information in which the contents (output characteristics) are consistent are acquired from two or more power transmitters 20 within a predetermined period using the narrow-area wireless communication, the output characteristic of the power-transmitter information may be trusted. That is, the control may be changed based on the output characteristic of the power-transmitter information, and the protection mode of the protection unit 501 at the time of abnormality may be changed.

[0123] In the above embodiment, the short-circuit control may be performed by turning on 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 of the rectifier circuit 200 instead of the short-circuit switch SW11.

[0124] In the above embodiment, the protection unit 501 may change the impedance of the power receiver circuit 500 according to the protection mode. In the above embodiment, the characteristic of the protection unit 501 is identified by the place where the protection unit 501 is provided. For example, in a case where the protection unit 501 is provided between the power-receiver resonant circuit 140 and the filter circuit 182, the characteristic is identified depending on the output characteristic from the power-receiver resonant circuit 140 to the filter circuit 182. Similarly, in a case where the protection unit 501 is provided between the filter circuit 182 and the rectifier circuit 200, the characteristic is identified depending on the output characteristic from the filter circuit 182 to the rectifier circuit 200. At this time, when determining the characteristic of the protection unit 501, the filter circuit 182 determines whether to invert the output characteristic of the power receiver coil 102 depending on the band-pass filter illustrated in FIG. 5 or the immittance filter illustrated in FIG. 6. Therefore, in step S3, the power-receiver control unit 230 determines the characteristic of the protection unit 501 based on the output characteristic of the power transmitter circuit 400 included in the power-transmitter information, the place where the protection unit 501 is provided, and the configuration of the power receiver circuit 500.

[0125] 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.

[0126] 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.

[0127] In the first embodiment, the traveling inverter 310 may be the “power supply target device”. 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.

[0128] 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. 11, 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 power-receiver control unit 230 may use the inter-vehicle communication unit 91 instead of other information acquisition units (such as narrow-area wireless communication and wide-area wireless communication), or may use the inter-vehicle communication unit together with other information acquisition units (such as narrow-area wireless communication and wide-area wireless communication).

[0129] 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.

[0130] As illustrated in FIG. 11, the position information acquisition unit 92 may be part of the information acquisition unit. That is, the power-receiver control unit 230 may use the position information acquisition unit 92 instead of other information acquisition units (such as narrow-area wireless communication and wide-area wireless communication), or may use the position information acquisition unit together with other information acquisition units (such as narrow-area wireless communication and wide-area wireless communication).

[0131] 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.

[0132] As illustrated in FIG. 11, the image recognition unit 93 may be part of the information acquisition unit. That is, the power-receiver control unit 230 may use the image recognition unit 93 instead of other information acquisition units (such as narrow-area wireless communication and wide-area wireless communication), or may use the image recognition unit together with other information acquisition units (such as narrow-area wireless communication and wide-area wireless communication).

[0133] 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.

[0134] As illustrated in FIG. 11, the marker recognition unit 94 may be part of the information acquisition unit. That is, the power-receiver control unit 230 may use the marker recognition unit 94 instead of other information acquisition units (such as narrow-area wireless communication and wide-area wireless communication), or may use the marker recognition unit together with other information acquisition units (such as narrow-area wireless communication and wide-area wireless communication).

[0135] 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 either of the inter-vehicle communication unit 91, the position information acquisition unit 92, the image recognition unit 93, or the marker recognition unit 94 described above.

[0136] In the above embodiment, the protection mode of the protection unit 501 may be set in advance after the output characteristic of the power transmitter circuit 400 is identified and before the main power supply is started, and the protection unit 501 may be immediately operated in the protection mode set in advance at the time of abnormality. For example, the protection mode may be set immediately after reception of the first power-transmitter information, or the protection mode may be set immediately after reception of the second power-transmitter information. In addition, the protection mode may be set immediately after the consistency of the power-transmitter information is checked.

[0137] Second Embodiment 　　　　　　 Hereinafter, the second embodiment will be described with reference to the drawings, focusing on differences from the first embodiment.

[0138] In the second embodiment, the power transmitter 20 varies the power waveform of the test radio wave during tracking according to the output characteristic of the power transmitter circuit 400. Specifically, at least one of the amplitude, the frequency, the wavelength, the number of waves, the current amount, and the transmission period of the test radio wave is varied according to the output characteristic of the power transmitter circuit 400. In the present embodiment, the frequencies are varied.

[0139] A power supply start process according to the second embodiment will be described with reference to FIG. 12. Since steps S1 to S9 are identical to those of the first embodiment, the description thereof will be omitted.

[0140] In the case of the affirmative determination in step S7 of the power supply start process, 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 (step S10), and advances the process to step S8 to start the main power supply. In this case, the power-receiver control unit 230 is an information acquisition unit and corresponds to a power transmission determination unit. Then, when checking the output characteristic in step S102 of the protection process, the power-receiver control unit 230 makes a determination by the output characteristic determined based on the test radio wave.

[0141] According to the second embodiment, the output characteristic can be checked even if the power-transmitter information cannot be acquired. In addition, since the output characteristic can be checked from the actually received power during tracking, the output characteristic can be accurately determined.

[0142] Third Embodiment 　　　　　　 Hereinafter, the third embodiment will be described with reference to the drawings, focusing on differences from the first embodiment.

[0143] In the third embodiment, the output characteristic of the power transmitter circuit 400 is determined based on the value of current flowing from the power receiver coil 102 under a condition that the power receiver coil 102 is short-circuited by the short-circuit switch SW11 turned on at the start of the wireless power transfer. Details will be described below.

[0144] In the third embodiment, as illustrated in FIG. 13, a current sensor 502 together with the short-circuit switch SW11 is provided on an electric path connecting both ends of the power receiver coil 102. The measurement result of the current sensor 502 is input to the power-receiver control unit 230.

[0145] Next, the output characteristic check process of the third embodiment will be described with reference to FIG. 14. The output characteristic check process of FIG. 14 is executed, for example, immediately after the start of the main power supply illustrated in step S8. Not limited to this timing, the process may be performed at the timing when the wireless power transfer is performed from the power transmitter 20.

[0146] When the output characteristic check process is started, the power-receiver control unit 230 turns on the short-circuit switch SW11 so that the protection unit 501 is in the short-circuit protection mode (step S201). Next, the power-receiver control unit 230 acquires the current value from current sensor 502, and determines whether the current value increases (step S202).

[0147] When the current value increases (when step S202 is affirmative), that is, when the current input from the power receiver coil 102 to the power receiver circuit 500 is not the constant current, the power-receiver control unit 230 identifies that the output characteristic of the power transmitter circuit 400 is the current source (step S203). As described above, when the output characteristic of the power transmitter circuit 400 is the current source, the output is converted between the power transmitter coil 22 and the power receiver coil 102. Therefore, in this case, the output characteristic of the power receiver coil 102 when viewed from the power receiver circuit 500 is the voltage source.

[0148] When the current increases, a large current flows if the current is left as it is. Therefore, when the current increases to some extent, the power-receiver control unit 230 turns off the short-circuit switch SW11.

[0149] On the other hand, when the current value does not increase (when step S202 is negative), that is, when the current input from the power receiver coil 102 to the power receiver circuit 500 is the constant current, the power-receiver control unit 230 identifies that the output characteristic of the power transmitter circuit 400 is the voltage source (step S204). As described above, when the output characteristic of the power transmitter circuit 400 is the voltage source, the output is converted between the power transmitter coil 22 and the power receiver coil 102. Therefore, in this case, the output characteristic of the power receiver coil 102 when viewed from the power receiver circuit 500 is the current source.

[0150] In step S202 of the protection process of the third embodiment, it is confirmed that the output characteristic is the output characteristic identified in the output characteristic check process. As a result, the power-receiver control unit 230 corresponds to a characteristic determination unit.

[0151] According to the third embodiment, it is not necessary to acquire the power-transmitter information by narrow-area wireless communication, wide-area wireless communication, or the like. In addition, since the output characteristic is determined based on the actually transmitted power, the output characteristic can be accurately identified.

[0152] Fourth Embodiment 　　　　　　 Hereinafter, the fourth embodiment will be described with reference to the drawings, focusing on differences from the first embodiment.

[0153] In the fourth embodiment, the current increase is suppressed by changing the inductor or capacitance of the power receiver circuit 500 at the time of abnormality.

[0154] First, a circuit configuration of the fourth embodiment will be described with reference to FIG. 15. As illustrated in FIG. 15, a series connection body of the short-circuit switch SW11 and the current sensor 502 is provided between the power-receiver resonant circuit 140 and the filter circuit 182. More specifically, a series connection body of the short-circuit switch SW11 and the current sensor 502 is connected to one of the both ends of each series capacitor 141 constituting power-receiver resonant circuit 140, the one end being away from the power receiver coil 102 (that is, close to the filter circuit 182).

[0155] In the present embodiment, the series capacitor 141 constituting power-receiver resonant circuit 140 is referred to as a first capacitor 141A. A series connection body of a second capacitor 141B and a first change switch SW21 is connected in parallel to each first capacitor 141A of the power-receiver resonant circuit 140. The capacitance (electrostatic capacitance) of the first capacitor 141A is larger than the capacitance of the second capacitor 141B. When the first change switch SW21 is turned on, the capacitance of the whole circuit of the power-receiver resonant circuit 140 increases.

[0156] The power receiver coil 102 of the fourth embodiment includes a first coil 102a and a second coil 102b. The second coil 102b is configured to be short-circuited by a second change switch SW22. That is, the inductance of the closed circuit including the power receiver coil 102 and the power-receiver resonant circuit 140 when the short-circuit switch SW11 is turned on can be changed (reduced) by turning on the second change switch SW22.

[0157] On / off of the first change switch SW21 and the second change switch SW22 is controlled by an instruction of the power-receiver control unit 230. The short-circuit switch SW11, the second capacitor 141B, the first change switch SW21, and the second change switch SW22 constitute a protection unit 511 of the fourth embodiment. The protection mode of the protection unit 511 is changed by turning on and off the first change switch SW21 and the second change switch SW22.

[0158] Next, a flow of the protection process at the time of abnormality detection according to the fourth embodiment will be described with reference to FIG. 16. The protection process is performed by the power-receiver control unit 230.

[0159] As in step S101, the power-receiver control unit 230 determines whether an abnormality has occurred in the power receiver circuit 500 (step S301).

[0160] When the determination result of step S301 is negative, the power-receiver control unit 230 ends the protection process. On the other hand, when the determination result of step S301 is affirmative, the power-receiver control unit 230 turns on the short-circuit switch SW11 to short-circuit power receiver coil 102 (step S302).

[0161] Next, the power-receiver control unit 230 determines whether the output characteristic of the power transmitter circuit 400 is a voltage source (step S303). The output characteristic of the power transmitter circuit 400 is confirmed (determined) by, for example, the output characteristic included in the power-transmitter information of which the consistency is confirmed in step S3. In step S303, it is determined whether the power transmitter circuit 400 is of the SS topology. As described above, since the output characteristic is converted when power is transmitted from the power transmitter coil 22 to the power receiver coil 102, in step S303, it is determined whether the output characteristic of the power receiver coil 102, that is, the output characteristic at both ends of the short-circuit switch SW11 when viewed from the filter circuit 182 is the current source.

[0162] When the determination result is affirmative, the power-receiver control unit 230 ends the process while keeping the short-circuit switch SW11 turned on. On the other hand, when the determination result in step S303 is negative, that is, when the power transmitter circuit 400 is a circuit of the Double-LCC topology and the output characteristic at both ends of the short-circuit switch SW11 is a voltage source, the power-receiver control unit 230 changes either the inductance or the capacitance of the closed circuit including the power receiver coil 102 and the power-receiver resonant circuit 140 according to the drive frequency of the power transmitter 20 (step S304).

[0163] In step S304, either the inductance or the capacitance of the closed circuit is changed so that the peak of the resonance frequency of the closed circuit is away from the drive frequency of the power transmitter 20. When the change switches SW21 and SW22 are turned off, the peak of the resonance frequency of the closed circuit can be calculated by the inductance of the power receiver coil 102 and the first capacitor 141A. In the present embodiment, the peak is stored in advance in the storage unit of the power-receiver control unit 230. In addition, the drive frequency of the power transmitter 20 is included in, for example, the power-transmitter information, and the power-receiver control unit 230 can identify the drive frequency band by acquiring the power-transmitter information.

[0164] Then, as illustrated in FIG. 17, when the drive frequency band BW1 is smaller than the peak PK of the resonance frequency (in the case of the left), the inductance or capacitance of the closed circuit is reduced so that the peak PK of the resonance frequency is shifted to the right, that is, is a high frequency. Specifically, the power-receiver control unit 230 turns on the second change switch SW22, and changes the power receiver coil 102 to the first coil 102a in the closed circuit to reduce the inductance of the closed circuit. As a result, the power receiver coil 102 (first coil 102a) is less likely to receive power from the power transmitter coil 22, and a large current can be suppressed. Although the second coil 102b is short-circuited, the capacitance and inductance are reduced, so that a large current can be suppressed.

[0165] In addition, as illustrated in FIG. 17, when the drive frequency band BW2 is larger than the peak PK of the resonance frequency (in the case of the right), the inductance or capacitance of the closed circuit is increased so that the peak PK of the resonance frequency is shifted to the left, that is, is a low frequency. Specifically, the power-receiver control unit 230 turns on first change switch SW21, and energizes second capacitor 141B in the closed circuit to increase the capacitance of the closed circuit. As a result, the power receiver coil 102 is less likely to receive power from the power transmitter coil 22, and a large current can be suppressed.

[0166] Fifth Embodiment 　　　　　　 Hereinafter, the fifth embodiment will be described with reference to the drawings, focusing on differences from the first embodiment.

[0167] As illustrated in FIG. 18, the power receiver circuit 500 in the fifth 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.

[0168] Next, the power supply start process of the fifth embodiment will be described with reference to FIG. 19. Steps S1 to S8 are similar to those in the first embodiment, and thus description thereof is omitted. In the fifth embodiment, when the determination result of step S4 is negative, the power-receiver control unit 230 performs the switching process for changing the output characteristic (step S11). In step S11, 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, and the change is set. Then, the power-receiver control unit 230 advances the process to step S5.

[0169] After performing step S11, when main power supply (wireless power transfer) is started in step S8, 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.

[0170] 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 disadvantage. That is, substantially, the output characteristic from the power receiver circuit 500 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 power receiver circuit 500 to the high-voltage storage battery 300.

[0171] Sixth Embodiment 　　　　　　 Hereinafter, the sixth embodiment will be described with reference to the drawings, focusing on differences from the first embodiment.

[0172] In the sixth 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. 20. In the sixth embodiment, the power receiver circuit 500 serving as a base is a circuit of the Double-LCC topology.

[0173] The power receiver circuit 500 includes a characteristic changeover switch SW (in the sixth 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 (open state) in the normal state, and the power receiver circuit 500 in the normal state is a circuit of the Double-LCC topology. Therefore, the output characteristic required by the power receiver circuit 500 is a current source.

[0174] FIG. 21 is a flowchart of the power supply start process executed by the power-receiver control unit 230. Steps S1 to S8 are identical to those in the first embodiment, and thus description thereof is omitted.

[0175] In the sixth 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 topology), the power-receiver control unit 230 performs the switching process (step S12). In step S12, the power-receiver control unit 230 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 control unit 230 advances the process to step S5.

[0176] After step S12, when main power supply (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.

[0177] When the characteristic changeover switch SWA is turned off in the normal state, the power receiver circuit 500 is identical to the circuit of the Double-LCC topology. 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.

[0178] 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. 22. In the fifth embodiment, the power receiver circuit 500 serving as a base is a circuit of the SS topology.

[0179] The power receiver circuit 500 includes a characteristic changeover switch SWB connected in parallel to each series capacitor 183B. When the characteristic changeover switch SWB is turned off, the filter circuit 182 functions as a normal band-pass filter and does not function as an immittance converter. On the other hand, when the characteristic changeover switch SWB is turned on, the series capacitor 183B 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.

[0180] The power-receiver control unit 230 performs a power supply start process similar to the process of FIG. 21. Specifically, the power-receiver control unit 230 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.

[0181] For example, when it is determined that the power transmitter circuit 400 is the circuit of the SS topology illustrated in FIG. 5, that is, when the output characteristic of the power transmitter circuit 400 is the voltage source, the power-receiver control unit 230 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 topology illustrated in FIG. 6, that is, when the output characteristic of the power transmitter circuit 400 is the current source, the power-receiver control unit 230 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.

[0182] 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.

[0183] Eighth Embodiment 　　　　　　 Hereinafter, the eighth 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. 23. In the present embodiment, the power receiver circuit 500 serving as a base is a circuit of the Double-LCC topology. In the present embodiment, the capacitor 184B is referred to as a first capacitor 184B.

[0184] 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.

[0185] The power-receiver control unit 230 performs a power supply start process similar to the process of FIG. 21. Specifically, the power-receiver control unit 230 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.

[0186] For example, when it is determined that the power transmitter circuit 400 is the circuit of the Double-LCC topology illustrated in FIG. 6, that is, when the output characteristic of the power transmitter circuit 400 is the current source, the power-receiver control unit 230 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 topology illustrated in FIG. 6, and power can be appropriately supplied.

[0187] On the other hand, when it is determined that the power transmitter circuit 400 is the circuit of the SS topology illustrated in FIG. 5, that is, when the output characteristic of the power transmitter circuit 400 is the voltage source, the power-receiver control unit 230 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.

[0188] According to the present embodiment described above, the same effects as those of the sixth embodiment can be obtained.

[0189] Modification of Eighth Embodiment 　　　　　　 The characteristic changeover switch SWD may be connected in series to the first capacitor 184B instead of the second capacitor 184D.

[0190] Ninth Embodiment 　　　　　　 Hereinafter, the ninth embodiment will be described with reference to the drawings, focusing on differences from the seventh embodiment. In the present embodiment, the power receiver circuit 500 is a circuit illustrated in FIG. 24. In the present embodiment, the power receiver circuit 500 serving as a base is a circuit of the Double-LCC topology. The electrostatic capacitance of the first capacitor 184B is identical to the electrostatic capacitance of the second capacitor 184D.

[0191] 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.

[0192] The power-receiver controller 231 performs a power supply start process similar to the process of FIG. 21. 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.

[0193] For example, when it is determined that the power transmitter circuit 400 is the circuit of the Double-LCC topology illustrated in FIG. 6, that is, when the output characteristic of the power transmitter circuit 400 is the current source, the power-receiver control unit 230 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 topology illustrated in FIG. 6, and power can be appropriately supplied.

[0194] On the other hand, when it is determined that the power transmitter circuit 400 is the circuit of the SS topology illustrated in FIG. 5, that is, when the output characteristic of the power transmitter circuit 400 is the voltage source, the power-receiver control unit 230 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.

[0195] According to the present embodiment described above, the same effects as those of the sixth embodiment can be obtained.

[0196] Tenth Embodiment 　　　　　　 Hereinafter, the tenth embodiment will be described with reference to the drawings, focusing on differences from the above embodiments. In the present embodiment, as illustrated in FIG. 25, the power receiver circuit 500 is configured to be switchable between an S topology (series topology) and a P topology (parallel topology).

[0197] 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.

[0198] The power-receiver control unit 230 performs a power supply start process similar to the process of FIG. 21. Specifically, the power-receiver control unit 230 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.

[0199] For example, when it is determined that the power transmitter circuit 400 is the circuit of the SS topology illustrated in FIG. 5, that is, when the output characteristic of the power transmitter circuit 400 is the voltage source, the power-receiver control unit 230 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 topology in which each series capacitor 141 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 topology illustrated in FIG. 5, and power can be appropriately supplied.

[0200] On the other hand, when it is determined that the power transmitter circuit 400 is the circuit of the Double-LCC topology illustrated in FIG. 6, that is, when the output characteristic of the power transmitter circuit 400 is the current source, the power-receiver control unit 230 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 topology in which the parallel capacitor 142 is connected in parallel to the power receiver coil 102. By being set to the P topology, 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.

[0201] Eleventh Embodiment 　　　　　　 Hereinafter, the eleventh embodiment will be described with reference to the drawings, focusing on differences from the tenth embodiment. Also in the present embodiment, as illustrated in FIG. 26, the output characteristic can be switched by providing a resonant coil 25 that resonates with the power receiver coil 102.

[0202] 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.

[0203] The power-receiver control unit 230 performs the power supply process similar to the process of FIG. 21. 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.

[0204] For example, when it is determined that the power transmitter circuit 400 is the circuit of the SS topology illustrated in FIG. 5, that is, when the output characteristic of the power transmitter circuit 400 is the voltage source, the power-receiver control unit 230 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 topology illustrated in FIG. 5, and power can be appropriately supplied.

[0205] On the other hand, when it is determined that the power transmitter circuit 400 is the circuit of the Double-LCC topology illustrated in FIG. 6, that is, when the output characteristic of the power transmitter circuit 400 is the current source, the power-receiver control unit 230 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.

[0206] Other Embodiments 　　　　　　 Each of the above embodiments may be modified as follows.

[0207] In step S3 of the above 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.

[0208] 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.

[0209] 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.

[0210] 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 transfer is generated in the power receiver coil 102.

[0211] 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.

[0212] 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.

[0213] 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.

[0214] 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.

[0215] 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.

[0216] 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.

[0217] 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.

[0218] 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 receiver comprising: 　　　　　　 an abnormality detection unit (230) configured to detect an abnormality during the wireless power transfer; 　　　　　　 a protection unit (501) configured to execute protection of the power receiver circuit when the abnormality is detected by the abnormality detection unit; 　　　　　　 an information acquisition unit (240, 332) configured to acquire power-transmitter information including at least an output characteristic of the power transmitter circuit; and 　　　　　　 a power-receiver control unit (230) configured to change a protection mode of the protection unit according to the output characteristic acquired by the information acquisition unit.

2. The power receiver according to claim 1, wherein 　　　　　　 the information acquisition unit includes a first information acquisition unit configured to acquire information from within a predetermined range, and a second information acquisition unit configured to acquire information from within a range wider than the predetermined range, and 　　　　　　 at least the second information acquisition unit of the power-receiver control unit is configured to acquire the power-transmitter information before the wireless power transfer is performed.

3. The power receiver according to claim 2, wherein 　　　　　　 the first information acquisition unit and the second information acquisition unit of the information acquisition unit are configured to acquire the power-transmitter information before the wireless power transfer is performed, and wherein 　　　　　　 the power-receiver control unit is configured to change the protection mode of the protection unit according to the output characteristic included in the power-transmitter information when the power-receiver control unit determines that content of the power-transmitter information acquired by the second information acquisition unit and content of the power-transmitter information acquired by the first information acquisition unit are consistent with each other.

4. The power receiver according to claim 3, wherein 　　　　　　 the power-receiver control unit is configured to change the protection mode of the protection unit according to the output characteristic included in the power-transmitter information acquired by the first information acquisition unit when the power-receiver control unit determines that the content of the power-transmitter information acquired by the second information acquisition unit and the content of the power-transmitter information acquired by the first information acquisition unit are not consistent.

5. The power receiver according to claim 3, wherein 　　　　　　 the power-receiver control unit is configured to change the protection mode of the protection unit according to the output characteristic included in the power-transmitter information when the power-receiver control unit determines that the content of the power-transmitter information acquired by the second information acquisition unit and the content of the power-transmitter information acquired by the first information acquisition unit are not consistent, and the first information acquisition unit acquires multiple pieces of the power-transmitter information which are consistent in content from two or more power transmitters within a predetermined period.

6. The power receiver according to claim 1, wherein 　　　　　　 the power transmitter is configured to transmit a test radio wave having a power waveform that includes one or multiple predetermined cycles, before power is supplied to a power supply target device by the wireless power transfer, 　　　　　　 the waveform of the test radio wave corresponds to the output characteristic of the power transmitter circuit, 　　　　　　 the information acquisition unit 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 　　　　　　 the power-receiver control unit is configured to change the protection mode of the protection unit according to the output characteristic determined by the power transmission determination unit.

7. The power receiver according to claim 1, wherein 　　　　　　 the protection unit includes a short-circuit switch (SW11) configured to short-circuit the power receiving antenna to restrict power supply from the power receiving antenna to a power supply target device, 　　　　　　 the information acquisition unit includes a characteristic determination unit (230) configured to 　　　　　　　　　　　　　 monitor a value of current flowing from the power receiving antenna under a condition that the power receiving antenna is short-circuited by the short-circuit switch turned on at a start of the wireless power transfer, and 　　　　　　　　　　　　　 determine the output characteristic based on whether the value of current increases, and 　　　　　　 the power-receiver control unit changes the protection mode of the protection unit according to the output characteristic determined by the characteristic determination unit.

8. The power receiver according to any one of claims 1 to 7, wherein 　　　　　　 the protection unit includes an open switch (SW12) is configured to switch between energization and de-energization between the power receiving antenna and a power supply target device, and a short-circuit switch (SW11) configured to short-circuit the power receiving antenna to restrict power supply from the power receiving antenna to the power supply target device, 　　　　　　 the protection unit is configured to be set to an open protection mode, in which energization between the power receiving antenna and the power supply target device is cut off by turning off the open switch, and a short-circuit protection mode, in which the power receiving antenna is short-circuited by turning on the short-circuit switch, and 　　　　　　 the power-receiver control unit is configured to 　　　　　　　　　　　　　 determine a characteristic of the protection unit based on the output characteristic of the power transmitter circuit, 　　　　　　　　　　　　　 control the protection unit to be set to the short-circuit protection mode in an event of the abnormality when the characteristic of the protection unit is close to a current source characteristic, and 　　　　　　　　　　　　　 control the protection unit to be set to the open protection mode in the event of the abnormality when the characteristic of the protection unit is close to a voltage source characteristic.

9. The power receiver according to claim 8, further comprising: 　　　　　　 a rectifier (200) configured to rectify a current input from the power receiving antenna, wherein 　　　　　　 the rectifier is a switching rectifier including multiple switching elements, and 　　　　　　 one or some of switching elements (S11H, S12H, S11L, S12L) constituting the rectifier is used as the short-circuit switch.

10. The power receiver according to any one of claims 1 to 7, wherein 　　　　　　 the protection unit has a circuit configuration configured to change at least either value of an inductance of an inductor (102, 102a, 102b) or a capacitance of a capacitor (141A, 141B), the inductor constituting the power receiver circuit between the power receiving antenna and a power supply target device (300), the capacitor constituting the power receiver circuit, and 　　　　　　 the power-receiver control unit is configured to control the protection unit to change at least either of the inductance or the capacitance when the output characteristic acquired by the information acquisition unit is a voltage source characteristic.

11. The power receiver according to claim 10, wherein 　　　　　　 the power-transmitter information acquired by the information acquisition unit includes a drive frequency of the power transmitter, and 　　　　　　 the power-receiver control unit is configured to control the protection unit to change at least either of the inductance or the capacitance so that a peak of a resonance frequency of the power receiver circuit moves away from the drive frequency of the power transmitter when the output characteristic acquired by the information acquisition unit is the voltage source characteristic.

12. The power receiver according to claim 10, wherein 　　　　　　 the protection unit includes a short-circuit switch (SW11) configured to short-circuit the power receiving antenna to restrict power supply from the power receiving antenna to the power supply target device, and 　　　　　　 the power-receiver control unit is configured to change at least either of the inductance or the capacitance in a state of the short-circuit protection mode in which the power receiving antenna is short-circuited by turning on the short-circuit switch in an event of the abnormality when the output characteristic acquired by the information acquisition unit is the voltage source characteristic.

13. The power receiver according to any one of claims 1 to 7, wherein 　　　　　　 the protection unit is configured to change impedance of the power receiver circuit according to the protection mode.

14. A program for a power receiver (100) 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 program causing the power receiver to execute: 　　　　　　 an abnormality detection step of detecting an abnormality during the wireless power transfer; 　　　　　　 a protection step of executing protection of the power receiver circuit by using a protection unit when the abnormality is detected in the abnormality detection step; 　　　　　　 an information acquisition step of acquiring power-transmitter information including at least an output characteristic of the power transmitter circuit; and 　　　　　　 a change step of changing a protection mode of the protection unit according to the output characteristic acquired in the information acquisition step.

15. A control method performed by a power receiver (100) 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 control method comprising: 　　　　　　 an abnormality detection step of detecting an abnormality during the wireless power transfer; 　　　　　　 a protection step of executing protection of the power receiver circuit by using a protection unit when an abnormality is detected in the abnormality detection step; 　　　　　　 an information acquisition step of acquiring power-transmitter information including at least an output characteristic of the power transmitter circuit; and 　　　　　　 a change step of changing a protection mode of the protection unit according to the output characteristic acquired in the information acquisition step.

Images