Power receiver device, vehicle, wireless power transfer system, wireless power transfer program, and control method for wireless power transfer system

Abstract

The power-receiver control unit (230) supplies a stop request signal, which indicates a request to stop power supply to a power transmitter antenna, to a power-receiver communication antenna (170), when a specified stop condition, which is for requesting the power transmitter antenna (22) to stop supplying power, is satisfied. When determining that there is a power supply stop request based on the stop request signal received by the power-transmitter communication antenna (40), the power-transmitter control unit (70) stops the power supply prior to determination that there is a power supply request. The power-receiver control unit determines that a function of the power-receiver communication antenna to transmit the stop request signal or a function of the power-transmitter communication antenna to receive the stop request signal is abnormal, based on power supply that is performed even though the stop request signal is supplied to the power-receiver communication antenna.

Description

POWER RECEIVER DEVICE, VEHICLE, WIRELESS POWER TRANSFER SYSTEM, WIRELESS POWER TRANSFER PROGRAM, AND CONTROL METHOD FOR WIRELESS POWER TRANSFER SYSTEMCross Reference

[0001] This application is based on Japanese Application No. 2024-208024 filed on November 29, 2024, the contents of which are incorporated herein by reference.

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

[0003] For example, Patent Literature 1 discloses a system for executing wireless power transfer from a ground-based power transmitter to a power receiver installed in an electric vehicle. The power transmitter device includes a power transmitter coil and a power-transmitter communication antenna. The power receiver device includes a power receiver coil, which is supplied with electric power wirelessly from the power transmitter coil, and a power-receiver communication antenna. The power receiver device supplies a power supply request signal, which indicates a power supply request to the power transmitter coil, to the power-receiver communication antenna. the power transmitter device determines whether there is the power supply request based on an output signal of the power-transmitter communication antenna. When the power transmitter device determines that there is the power supply request, the power transmitter device energizes the power transmitter coil. On the other hand, when the power transmitter device determines that there is no power supply request, the power transmitter device stops energization of the power transmitter coil.

[0004] JP2024-8088A

[0005] However, for some reason, a communication range of the power supply request signal transmitted from the vehicle may become excessively large. In this case, even though no power supply request signal is transmitted to the power-receiver communication antenna, there is a risk that electric power would be supplied from the power transmitter coil (power transmitter antenna) to the power receiver coil (power receiver antenna) of another vehicle near the vehicle that causes the excessively extended communication range.

[0006] In this regard, it is conceivable to cause the power-receiver communication antenna in the power receiver device to supply a stop request signal, which indicates a request to stop power supply with respect to the power transmitter coil. However, even in this case, there is a risk that an abnormality would occur in the function to transmit and receive the stop request signal of the wireless power transfer system. Therefore, a technique that enables to detect such an abnormality is desirable.

[0007] It is an object of the present disclosure to enable to determine whether a function of a wireless power transfer system for transmitting and receiving a stop request signal is abnormal.

[0008] According to a first aspect to address the above-mentioned issue, a power receiver device is to be applied to a wireless power transfer system. The wireless power transfer system includes: a power transmitter device including a power transmitter antenna, at least one power-transmitter communication antenna, and a power-transmitter control unit; and the power receiver device, the power receiver device comprises: a power receiver antenna configured to wirelessly receive power from the power transmitter antenna; at least one power-receiver communication antenna configured to wirelessly communicate with the power-transmitter communication antenna; and a power-receiver control unit. The power-receiver control unit is configured to supply a power supply request signal, which indicates power supply request to the power transmitter antenna, to the power-receiver communication antenna, and stop supply of the power supply request signal. The power-transmitter control unit is configured to, based on the power supply request signal received by the power-transmitter communication antenna, cause the power transmitter antenna to supply power to the power receiver antenna when determining that there is the power supply request, and stop power supply when determining that there is no power supply request. The receiver control unit is configured to supply a stop request signal, which indicates power supply stop request for requesting the power transmitter antenna to stop power supply, to the power-receiver communication antenna, when a specified stop condition, which is for requesting the power transmitter antenna to stop power supply, is satisfied. The power-transmitter control unit is configured to stop power supply, prior to determination that there is the power supply request, when determining that there is the power supply stop request based on the stop request signal received by the power-transmitter communication antenna. The receiver control unit is configured to determine that a function of the power-receiver communication antenna to transmit the stop request signal or a function of the power-transmitter communication antenna to receive the stop request signal is abnormal, based on power supply that is performed even though supplying the stop request signal to the power-receiver communication antenna.

[0009] According to the above configuration, the power receiver antenna wirelessly receives power from the power transmitter antenna. The at least one power-receiver communication antenna performs wireless communication with the power-transmitter communication antenna.

[0010] Herein, the power-receiver control unit supplies the power supply request signal to the power-receiver communication antenna and stops supplying of the power supply request. The power-transmitter control unit is configured to, based on the power supply request signal received by the power-transmitter communication antenna, cause the power transmitter antenna to supply power to the power receiver antenna when determining that there is a power supply request, and stop the power supply when determining that there is no power supply request. Therefore, the power-receiver control unit enables to switch between supplying power from the power transmitter antenna to the power receiver antenna and stopping the power supply by supplying the power supply request signal and stopping the supply of the power supply request signal.

[0011] However, even when the power-receiver control unit does not supply the power supply request signal, for example, power may be supplied from the power transmitter antenna to the power receiver antenna. In view of this, the receiver control unit is configured to supply a stop request signal, which is for requesting the power transmitter antenna to stop power supply, to the power-receiver communication antenna, when a specified stop condition, which is for requesting the power transmitter antenna to stop power supply, is satisfied. The power-transmitter control unit is configured to stop power supply, prior to determination that there is the power supply request, when determining that there is the power supply stop request based on the stop request signal received by the power-transmitter communication antenna. Therefore, when power is supplied from the power transmitter antenna to the power receiver antenna, even though no power supply is requested, the power-receiver control unit enables to stop the power supply.

[0012] However, when an abnormality occurs in the function of the wireless power transfer system to transmit and receive the stop request signal, there is a risk that power may be supplied from the transmitter antenna to the receiving antenna even though no power supply request is made. In view of this, the receiver control unit is configured to determine that a function of the power-receiver communication antenna to transmit the stop request signal or a function of the power-transmitter communication antenna to receive the stop request signal is abnormal, based on power supply that is performed even though supplying the stop request signal to the power-receiver communication antenna. Therefore, it is possible to determine that the function of the wireless power transfer system to transmit and receive the stop request signal is abnormal.

[0013] According to a second aspect, a wireless power transfer program is to be applied to a wireless power transfer system. The wireless power transfer system includes: a power transmitter device including a power transmitter antenna, a power-transmitter communication antenna, and a power-transmitter control unit; and a power receiver device including a power receiver antenna configured to wirelessly receive power from the power transmitter antenna, at least one power-receiver communication antenna configured to wirelessly communicate with the power-transmitter communication antenna, and a power-receiver control unit. The wireless power transfer program is configured to carry out: executing a process to cause the power-receiver control unit to supply a power supply request signal, which indicates power supply request to the power transmitter antenna, to the power-receiver communication antenna, and stop supply of the power supply request signal; executing a process to cause the power-transmitter control unit to, based on the power supply request signal received by the power-transmitter communication antenna, cause the power transmitter antenna to supply power to the power receiver antenna when determining that there is the power supply request, and stop power supply when determining that there is no power supply request; executing a process to cause the receiver control unit to supply a stop request signal, which indicates power supply stop request for requesting the power transmitter antenna to stop power supply, to the power-receiver communication antenna, when a specified stop condition, which is for requesting the power transmitter antenna to stop power supply, is satisfied; executing a process to cause the power-transmitter control unit to stop power supply, prior to determination that there is the power supply request, when determining that there is the power supply stop request based on the stop request signal received by the power-transmitter communication antenna; and executing a process to cause the receiver control unit to determine that a function of the power-receiver communication antenna to transmit the stop request signal or a function of the power-transmitter communication antenna to receive the stop request signal is abnormal, based on power supply that is performed even though supplying the stop request signal to the power-receiver communication antenna.

[0014] The above configuration enables, in the wireless power transfer program to be applied to the wireless power transfer system, to achieve the same advantageous effects as those of the first aspect.

[0015] According to a third aspect, a control method is for a wireless power transfer system. The wireless power transfer system includes: a power transmitter device including a power transmitter antenna, a power-transmitter communication antenna, and a power-transmitter control unit; and a power receiver device including a power receiver antenna configured to wirelessly receive power from the power transmitter antenna, at least one power-receiver communication antenna configured to wirelessly communicate with the power-transmitter communication antenna, and a power-receiver control unit. The control method comprises: executing a process to cause the power-receiver control unit to supply a power supply request signal, which indicates power supply request to the power transmitter antenna, to the power-receiver communication antenna, and stop supply of the power supply request signal; executing a process to cause the power-transmitter control unit to, based on the power supply request signal received by the power-transmitter communication antenna, cause the power transmitter antenna to supply power to the power receiver antenna when determining that there is the power supply request, and stop power supply when determining that there is no power supply request; executing a process to cause the receiver control unit to supply a stop request signal, which indicates power supply stop request for requesting the power transmitter antenna to stop power supply, to the power-receiver communication antenna, when a specified stop condition, which is for requesting the power transmitter antenna to stop power supply, is satisfied; executing a process to cause the power-transmitter control unit to stop power supply, prior to determination that there is the power supply request, when determining that there is the power supply stop request based on the stop request signal received by the power-transmitter communication antenna; and executing a process to cause the receiver control unit to determine that a function of the power-receiver communication antenna to transmit the stop request signal or a function of the power-transmitter communication antenna to receive the stop request signal is abnormal, based on power supply that is performed even though supplying the stop request signal to the power-receiver communication antenna.

[0016] The above configuration enables, in the control method for the wireless power transfer system, to achieve the same advantageous effects as those of the first aspect.

[0017] The drawings described herein are intended to illustrate selected embodiments, do not depict all possible embodiments, and are not intended to limit the scope of the present disclosure.

[0018] FIG. 1 is an overall configuration diagram of a wireless power transfer system according to a first embodiment.FIG. 2 is a diagram showing the wireless power transfer system and a vehicle.FIG. 3 is a diagram illustrating a power transmitter and a power receiver.FIG. 4 is a diagram illustrating a power-receiver control unit and its peripheral configuration.FIG. 5 is a flowchart showing a transmission process of a power supply request signal executed by the power receiver.FIG. 6 is a diagram showing a state in which erroneous power supply occurs due to a vehicle with an expanded communication range.FIG. 7 is a flowchart of a transmission process of a stop request signal and an abnormality determination process executed by the power receiver.FIG. 8 is a diagram showing an example of instructing a driver to deviate from a power supply lane.FIG. 9 is a flowchart of a power transmitter coil energization control process executed by the power transmitter.FIG. 10 is a flowchart of a transmission process of a stop request signal and an abnormality determination process executed by a power receiver according to a second embodiment.FIG. 11 is a diagram showing a modified example of a power transmitter and a modified example of a power receiver.FIG. 12 is a diagram showing a modified example of a power transmitter and a power receiver.FIG. 13 is a diagram showing a modified example of a power transmitter and a power receiver.FIG. 14 is a diagram showing an arrangement of a power-transmitter communication coil.

[0019] Multiple embodiments will be described with reference to the drawings. In some embodiments, parts that are functionally and / or structurally corresponding to each other and / or associated with each other are given the same reference numerals, or reference numerals with different hundred digit or more digits. The corresponding and / or associated parts may refer to the explanation in the other embodiments.

[0020] <First Embodiment> A first embodiment of a wireless power transfer system of the present disclosure will be described below with reference to the drawings.

[0021] First, an overall configuration of the wireless power transfer system will be described. As shown in FIGS. 1, 2, and 3, the wireless power transfer system 10 includes a power transmitter 20 and a power receiver 100. The power receiver 100 is mounted on a vehicle 11 as a moving object that travels on a road RS, and is a vehicle-side device. The vehicle 11 is, for example, an electric automobile or a hybrid vehicle. While the vehicle 11 is traveling or stopped (including parked), electric power is supplied from the power transmitter 20 to the power receiver 100. The wireless power transfer system 10 executes wireless power transfer from the power transmitter 20 to the power receiver 100 through magnetic field resonance coupling (magnetic field resonance). The wireless power transfer system 10 is also referred to as a dynamic wireless power transfer (D-WPT) system.

[0022] The power transmitter 20 is a ground-side device and has a power-transmitter coil unit 21 and a power-transmitter 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 (also indicated as "GA") is installed (for example, buried) on a road RS, a parking lot, or the like. The power-transmitter power supply unit 51 (also indicated as "MU") is installed, for example, at the side of the road RS. The power-transmitter coil unit 21 is connected to the power-transmitter power supply unit 51. The power-transmitter power supply unit 51 is connected to an AC power source 15 and supplies AC (alternating-current) power from the AC power source 15 to the power-transmitter coil unit 21. The AC power source 15 is, for example, a commercial power source. Multiple power-transmitter coil units 21 are arranged along the lanes of the road RS. FIG. 2 shows an example of four power-transmitter coil units 21 aligned along the road RS and connected to one power-transmitter power supply unit 51. In other words, one power-transmitter power supply unit 51 is provided for the four power-transmitter coil units 21. The configuration is not limited to one power-transmitter power supply unit 51 for the multiple power-transmitter coil units 21, but one power-transmitter power supply unit 51 may be provided for each power-transmitter coil unit 21.

[0023] The power-transmitter power supply unit 51 includes a PFC (Power Factor Correction) 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 source 15. The PFC circuit 61 includes switching elements (e.g., IGBTs or MOSFETs) that are switched and controlled to convert the input AC power to DC (direct current) power and improve a power factor of the AC power input from the AC power source 15.

[0024] The inverter 60 is connected to the PFC circuit 61. The inverter 60 includes switching elements (e.g., IGBTs or MOSFETs) that are switched and controlled to convert the DC power input from the PFC circuit 61 to AC power.

[0025] The filter circuit 52 removes noise contained in the AC current input from the inverter 60 and supplies the AC current from which noise has been removed to the power-transmitter coil unit 21. The filter circuit 52 is, for example, an LC filter that includes a coil and a capacitor. Circuits having various configurations can be used as the filter circuit 52, and, for example, a T-type filter circuit is used as the filter circuit 52.

[0026] The power-transmitter coil unit 21 includes a power transmitter coil 22 (corresponding to power transmitter 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 by the filter circuit 52 to the power transmitter coil 22. The power-transmitter resonant circuit 30 can employ various well-known resonant circuits such as a circuit including a resonant capacitor.

[0027] 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 receiver antenna"). The power-receiver coil unit 101 is located at the bottom of the vehicle body of the vehicle 11. When the vehicle 11 travels on the road RS where the power transmitter coil 22 is buried, the power transmitter coil 22 on the ground side and the power receiver coil 102 of the vehicle 11 face each other in the vertical direction.

[0028] 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. The power receiver coil 102 is supplied with power from the power transmitter coil 22. The power receiver coil 102 supplies the received power to the power-receiver resonant circuit 140. The power-receiver resonant circuit 140 can employ various well-known resonant circuits such as a circuit including a resonant capacitor.

[0029] The power receiver 100 includes a filter circuit 182, a rectifier circuit 200 that functions as a DC-AC conversion circuit, and a smoothing capacitor 210. The filter circuit 182 removes noise contained in the AC current input from the power-receiver resonant circuit 140 and supplies the AC current from which noise has been removed to the rectifier circuit 200. The filter circuit 182 of the present embodiment is, for example, an LC filter that includes reactor and a capacitor.

[0030] The rectifier circuit 200 converts the input AC current into a DC current and outputs the DC current. The rectifier circuit 200 is, for example, a full-bridge circuit including semiconductor switching elements, or a diode rectifier circuit. A first end of the smoothing capacitor 210 is connected to a high potential side output terminal of the rectifier circuit 200. A second end of the smoothing capacitor 210 is connected to a low potential side output terminal of the rectifier circuit 200. The rectifier circuit 200 is also referred to as an ERB (Electronic Rectification Box).

[0031] 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, for example, relays (specifically, mechanical relays). The high potential side output terminal of the rectifier circuit 200 is connected to a positive terminal of the high-voltage storage battery 300 via the high potential main switch 301H. The low potential side output terminal of the rectifier circuit 200 is connected to a negative terminal of the high-voltage storage battery 300 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 several hundred volts, for example. The high-voltage storage battery 300 is, for example, a lithium-ion storage battery or a nickel-metal hydride storage battery.

[0032] The vehicle 11 includes a travelling inverter 310 and a rotary electric machine 320. The travelling inverter 310 is a 3-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 windings of the rotary electric machine 320 are connected to the upper and lower arm switches that constitute the travelling inverter 310. By switching control of the upper and lower arm switches of the travelling inverter 310 while the high potential main switch 301H and the low potential main switch 301L are turned on, the travelling inverter 310 converts the DC power supplied from the high-voltage storage battery 300 into AC power and supplies the AC power to the armature winding. This configuration causes the rotor of the rotary electric machine 320 to rotate, and the rotational power of the rotor rotates drive wheels of the vehicle 11. As a result, the vehicle 11 travels.

[0033] As shown in FIG. 3, the power-transmitter power supply unit 51, which constitutes the power transmitter 20, includes a power-transmitter control unit 70. As shown in FIG. 3, the power-transmitter control unit 70 includes a power-transmitter control device 71. The power-transmitter control device 71 is an electronic control unit (ECU) that executes various controls of the power transmitter 20 and includes, as hardware, a processor, a storage unit, and a communication bus connecting the processor with the storage unit.

[0034] The storage unit includes a memory and a storage as hardware. The memory is a storage device for storing data used in the processing of the power-transmitter control device 71. The memory, for example, provides the processor with a work area for temporary use when the processor performs processing. The memory 212 includes, for example, RAM and ROM. 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, HDD or flash memory. The storage contains program information and other information for the processes described below.

[0035] The power-receiver power supply unit 181, which constitutes the power receiver 100, includes a power-receiver control device 231. The power-receiver control device 231 is an ECU that executes various controls of the power receiver 100, and includes a processor as hardware, a storage unit, and a communication bus that connects the processor and storage unit.

[0036] The storage unit includes a memory and a storage as hardware. The memory is a storage device for storing data used in the processing of the power-receiver control device 231. The memory, for example, provides the processor with a work area for temporary use when the processor performs processing. The memory 212 includes, for example, RAM and ROM. 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, HDD or flash memory. The storage contains program information and other information for the processes described below.

[0037] For example, the program information stored on the non-transitory tangible storage medium is installed in the storage units of the power-receiver control device 231 and the power-transmitter control device 71. The storage medium is, for example, a USB memory, CD-ROM or DVD. In addition, the program information transmitted over a communication network, such as OTA (Over The Air), for example, is installed in the storage unit.

[0038] The power-transmitter control device 71 executes a switching control of the PFC circuit 61 and a switching control of the inverter 60. Through the switching control of the inverter 60, a high-frequency AC voltage is applied to the power transmitter coil 22. This causes a high-frequency current to flow in the power transmitter coil 22 and a magnetic field for power transmission is generated in the power transmitter coil 22.

[0039] In this embodiment, the power-transmitter control device 71 switches and controls the inverter 60 so that the frequency of the high-frequency voltage applied to the power transmitter coil 22 is becomes a first specified frequency between 10 kHz and 100 GHz, specifically, 85 kHz. The resonant frequencies of the power-transmitter resonant circuit 30 and the power-receiver resonant circuit 140 are set at the same frequency or close to the first specified frequency.

[0040] When the magnetic field generated in the power transmitter coil 22 links with the power receiver coil 102 of the vehicle 11, a high-frequency current flows in the power receiver coil 102, varying with the frequency of the high-frequency current flowing in the power transmitter coil 22. The high-frequency current flowing in the power transmitter coil 22 is transmitted to the rectifier circuit 200 through the power-receiver resonant circuit 140 and the filter circuit 182. The rectifier circuit 200 converts the transmitted AC current into a DC current and outputs the DC current. While 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 travelling inverter 310.

[0041] 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. The power supplied from the low-voltage storage battery 302 to the power-receiver control device 231 enables the power-receiver control device 231 to operate.

[0042] The power receiver 100 includes a voltage sensor 330, a current sensor 340, and an intensity sensor 350 (corresponding to an "intensity detection unit"). The voltage sensor 330 detects voltages of various in-vehicle devices of the vehicle 11 (specifically, components of the power receiver 100), for example, a voltage of the smoothing capacitor 210. The current sensor 340 detects currents flowing in various in-vehicle devices of the vehicle 11 (specifically, the components of the power receiver 100), for example, currents flowing in the power receiver coil 102 and the rectifier circuit 200. The intensity sensor 350 detects an intensity value of short-range wireless communication transmitted from another vehicle present around the vehicle 11. The intensity sensor 350 can be a variety of sensors, such as, for example, a magnetoresistive sensor or a Hall effect sensor. The detected values of the sensors 330, 340, 350 are input to the power-receiver control device 231.

[0043] The power receiver 100 and the power transmitter 20 each have a configuration for communication between the power receiver 100 and the power transmitter 20. In detail, the power-receiver coil unit 101, which constitutes the power receiver 100, includes a power-receiver communication coil 170 (corresponding to a power-receiver communication antenna). A power-receiver control unit 230 includes a transmitter 240 (also indicated as "TX").

[0044] The power-transmitter coil unit 21, which constitutes 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 receiver 80 (also indicated as "RX"). The power-receiver communication coil 170 and the power-transmitter communication coil 40 are communication coils for narrow area wireless communication. The narrow area wireless communication is those with a communication distance of less than 10 meters (e.g., a maximum of about 3 meters). The narrow area wireless communication is a communication with a shorter communication distance than wide area wireless communication.

[0045] Various short-range wireless communications can be used as the narrow area wireless communication. For example, communications compliant with any communication standards established by IEEE, ISO, and IEC can be used. Specifically, for example, Wi-Fi (registered trademark), Bluetooth (registered trademark), ZigBee (registered trademark), RFID (Radio Frequency Identification), or DSRC (Dedicated Short Range Communication) can used as the narrow area wireless communication.

[0046] The transmitter 240 is connected to the power-receiver control device 231. The transmitter 240 is connected to the power-receiver communication coil 170. The power-receiver control device 231 controls the transmitter 240 to supply a power supply request signal COMM to the power-receiver communication coil 170. The power supply request signal is a signal requesting the power transmitter coil 22 near the vehicle 11 to transmit power to the power receiver coil 102. For example, when the state of charge (SOC) of the high-voltage storage battery 300 is 70% or less, the power-receiver control device 231 controls the transmitter 240 to supply the power supply request signal to the power-receiver communication coil 170.

[0047] The power-receiver control unit 230 controls the transmitter 240 to supply a vehicle-side signal including, in one frame, the power supply request signal and a traveling speed signal (corresponding to a traveling state signal) indicating a traveling speed Vsp (corresponding to a traveling state) of the vehicle 11 to the power-receiver communication coil 170. The power supply request signal includes ID information of the vehicle 11 and requested power Weq, which is a requested value of power to be supplied to the vehicle 11. This control causes a high-frequency voltage to be applied from the transmitter 240 to the power-receiver communication coil 170. Consequently, a high-frequency current flows in the power-receiver communication coil 170, and a magnetic field for information communication is generated in the power-receiver communication coil 170. The power-receiver control unit 230 is capable of communicating with, for example, a vehicle ECU that controls the vehicle 11, and acquires the ID information and the traveling speed Vsp of the vehicle 11 from the vehicle ECU. The communication between the power-receiver control unit 230 and the vehicle ECU may be wired communication or wireless communication. That is, the power-receiver control unit 230 is capable of communicating with the vehicle 11.

[0048] When the power-receiver coil unit 101 of the vehicle 11 approaches the power-transmitter coil unit 21 on the ground side, the generated magnetic field links to the power-transmitter communication coil 40, and a high-frequency current flows through the power-transmitter communication coil 40. This high frequency current is input to the receiver 80 shown in FIG. 3. The receiver 80 recognizes the presence or absence of a power supply request and ID information based on the input signal from the power-transmitter communication coil 40. The receiver 80 also acquires the requested power Weq for the vehicle 11 with the recognized ID information, based on the signal from the power-transmitter communication coil 40. The information recognized by the receiver 80 and the requested power Weq are input to the power-transmitter control device 71.

[0049] In this embodiment, the power-receiver control device 231 controls the transmitter 240 so that the frequency of the high-frequency voltage applied to the power-receiver communication coil 170 becomes a second specified frequency between 10 kHz and 100 GHz. In this embodiment, the second specified frequency is a frequency that deviates from the first specified frequency above, specifically a frequency higher than the first specified frequency (e.g., 13.56 MHz).

[0050] The power-transmitter control device 71 determines whether to energize the power transmitter coil 22 based on the input signal from the receiver 80. In detail, when the power-transmitter control device 71 determines that there is the power supply request based on the input signal from the receiver 80, the power-transmitter control device 71 applies high-frequency voltage to the power transmitter coil 22 by performing switching control of the inverter 60 and the PFC circuit 61. This results in a wireless power transfer from the power transmitter coil 22 to the power receiver coil 102. In addition, when the power-transmitter control device 71 determines that there is the power supply request, it actually performs a coupling determination process prior to executing the switching control of the inverter 60 and the PFC circuit 61 to determine whether the degree of magnetic coupling between the power receiver coil 102 and the power transmitter coil 22 is appropriate for power transmission. The power-transmitter control device 71 executes the switching control of the inverter 60 and the PFC circuit 61 on condition that the power-transmitter control device 71 has determined that the degree of magnetic coupling between the power receiver coil 102 and the power transmitter coil 22 is appropriate. As a result, the power transmitter coil 22 is energized while the power receiver coil 102 and the power transmitter coil 22 are in close proximity to each other.

[0051] The transmitter 240 and its peripheral configuration will be described with reference to FIG. 4.

[0052] The transmitter 240 includes a generating circuit 241, and a power-receiver amplifier 242. The generating circuit 241 is connected to the power-receiver control device 231 and the power-receiver amplifier 242. The generating circuit 241 generates a vehicle-side signal, which is a high-frequency signal including the power supply request signal and traveling speed signal, based on a command from the power-receiver control device 231. The frequency of the vehicle-side signal is the second specified frequency. The power-receiver amplifier 242 amplifies the high-frequency signal generated by the generating circuit 241 and supplies the amplified signal to the power-receiver communication coil 170.

[0053] The power-receiver control device 231 instructs the generating circuit 241 to generate a vehicle-side signal. The high-frequency signal output from the generating circuit 241 is amplified by the power-receiver amplifier 242. The amplified signal is supplied to the power-receiver communication coil 170.

[0054] FIG. 5 shows a flowchart of a transmission process of the power supply request signal executed by the power receiver 100.

[0055] In step S30, the power-receiver control device 231 determines whether there is the power supply request. When determining that there is the power supply request, the process proceeds to step S11 in which the power-receiver control device 231 instructs the generation circuit 241 to generate a vehicle-side signal including the power supply request signal. As a result, the vehicle-side signal from the generating circuit 241 is input to the power-receiver amplifier 242. The power-receiver amplifier 242 amplifies the input vehicle-side signal and supplies the amplified signal to the power-receiver communication coil 170.

[0056] On the other hand, when determining in step S10 that there is no power supply request, the process proceeds to step S12, in which the power-receiver control device 231 instructs the generation circuit 241 to stop generating the vehicle side signal. This causes the generation circuit 241 to stop outputting the vehicle side signal. As a result, the supply of the vehicle-side signal to the power-receiver communication coil 170 is stopped.

[0057] Returning to FIG. 3, the receiver 80 amplifies the high-frequency signal (high-frequency current or voltage signal) output from the power-transmitter communication coil 40. The high-frequency signal output from the power-transmitter communication coil 40 contains a frequency component that fluctuates at the second specified frequency.

[0058] Based on the high-frequency signal input from the power-transmitter amplifier, the receiver 80 calculates an intensity Intd which is an amplitude or effective value of the input high-frequency signal. The receiver 80 determines whether there is the power supply request to the power transmitter coil 22 based on the calculated intensity value Intd. Specifically, when determining that the intensity Intd exceeds a determination threshold Ijde, the receiver 80 determines that there is the power supply request. On the other hand, when determining that the intensity value Intd is lower than the determination threshold Ijde, the receiver 80 determines that there is no power supply request. The determination result information of the receiver 80 is input to the power-transmitter control device 71.

[0059] When determining that there is no power supply request based on the input determination result information, the power-transmitter control device 71 stops the switching control of the PFC circuit 61 and the inverter 60. As a result, the switches of the PFC circuit 61 and the inverter 60 are kept off, and the power transmitter coil 22 is not energized.

[0060] On the other hand, when determining that there is the power supply request based on the determination result information, the power-transmitter control device 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. This causes a high-frequency current to flow through the power transmitter coil 22. In this case, wireless power transfer from the power transmitter coil 22 to the power-receiver coil 102 that faces the power transmitter coil 22 in the vertical direction is performed.

[0061] Herein, in some cases, the intensity value of the power supply request signal supplied to the power-receiver communication coil 170 of the vehicle becomes excessively large, and a communication range of the power supply request signal transmitted from the vehicle may be excessively expanded. In FIG. 6, 500 indicates a vehicle with an excessively extended communication range. In case where the bottom of a vehicle 500 is at a high position, and the power-receiver coil unit 101 is at a high position, the communication range of the power supply request signal transmitted from the vehicle 500 may be excessively expanded.

[0062] In another vehicle 11 present near the vehicle 500 with the communication range, which has been excessively expanded, the power-transmitter communication coil 40 present nearby would receive the power supply request signal, even though the power supply request signal is not supplied to the power-receiver communication coil 170. As a result, the nearby power transmitter coil 22 is energized, and power is transmitted from the power transmitter coil 22 to the power receiver coil 102 of the vehicle 11, even though there is no power supply request to the vehicle 11.

[0063] In addition to the case where the vehicle 500 with the expanded communication range and another vehicle 11 are stopped, this issue would occur in a case where the vehicle 500 with the expanded communication range and another vehicle 11 are traveling, and where the relative speed between the vehicle 500 with the extended communication range and the other vehicle 11 is close to zero. Further, even if an abnormality occurs in a function that stops the power supply request signal (also if an abnormality occurs that causes the power supply request signal kept transmitted) in the power receiver 100, the issue that causes power transmission from the power transmitter coil 22 to the power receiver coil 102 of the vehicle 11 may occur, even though there is no power supply request for the vehicle 11.

[0064] In order to address such issues, the power-receiver control unit 230 supplies a stop request signal STOPCOMM to the power-receiver communication coil 170, when determining that a stop request condition (corresponding to specified stop condition) for requesting the power transmitter coil 22 to stop power supply is satisfied. The power-transmitter control unit 70 stops energization of the power transmitter coil 22, when determining that the stop request signal is input based on the output signal of the power-transmitter communication coil 40.

[0065] FIG. 7 is a flowchart of a transmission process for the stop request signal executed by the power-receiver control unit 230.

[0066] In step S20, the power-receiver control device 231 determines whether the stop request condition is satisfied. The stop request condition is, for example, a condition for detecting the presence of the vehicle 500 with an excessively extended communication range around the vehicle 11. The stop request condition is, for example, any one of the following conditions (A1) to (A4).

[0067] (A1) A condition that the power-receiver control device 231 determines that the vehicle 11 has switched from a state where there is the power supply request to a state where there is no power supply request. That is, in the process of FIG. 5, the condition (A1) is satisfied when the state where the determination is affirmative in step S10 is switched to the state where the determination is negative. According to the condition (A1), when there is no request for power supply to the vehicle 11, energization of the power transmitter coil 22 present near the vehicle 11 is stopped.

[0068] (A2) A condition that there is no power supply request in the vehicle 11 and a current is flowing through the power receiver coil 102. The state in which a current flows through the power receiver coil 102 even though there is no power supply request in the vehicle 11 means that there is a high possibility that the vehicle 500 with an excessively extended communication range of the power supply request signal is present nearby. The stop request condition (A2) enables to accurately determine that such a state exists. It may be determined whether a current flows through the power receiver coil 102 based on, for example, a current value of the power receiver coil 102 or the rectifier circuit 200 detected by the current sensor 340, or a voltage value of the power receiver coil 102 or the rectifier circuit 200 detected by the voltage sensor 330.

[0069] (A3) A condition that the intensity value ILoud detected by the intensity sensor 350 exceeds an intensity threshold value ILth. A state in which the intensity value ILoud detected by the intensity sensor 350 becomes excessively large and exceeds the intensity threshold value ILth is a state in which there is a high possibility that the vehicle 500 with an excessively extended communication range of the power supply request signal is present nearby. The stop request condition (A3) enables to accurately determine that such a state exists. The intensity threshold ILth is, for example, a value larger than the determination threshold Ijde.

[0070] (A4) A condition that the intensity value ILoud detected by the intensity sensor 350 exceeds the intensity threshold ILth and there is no power supply request in the vehicle 11. The stop request condition (A4) enables to more accurately determine that the vehicle 500 with an excessively extended communication range is highly likely to be present near the vehicle 11.

[0071] When determining in step S20 that the stop request condition is satisfied, the process proceeds to step S21 in which the power-receiver control device 231 instructs the generation circuit 241 to generate the stop request signal, which is a high frequency signal. As a result, the stop request signal generated by the generation circuit 241 is input to the power-receiver amplifier 242. The stop request signal amplified by the power-receiver amplifier 242 is supplied to the power-receiver communication coil 170. This causes the power-receiver communication coil 170 to transmit the stop request signal.

[0072] Regardless of the result of the determination of the presence or absence of the power supply request in the process of FIG. 5, when determining that the stop request condition is satisfied, the power-receiver control device 231 instructs the generation circuit 241 to stop generating the power supply request signal. That is, when determining that there is a power supply stop request based on the stop request signal received by the power-transmitter communication coil 40, the power supply is stopped prior to the determination that there is the power supply request.

[0073] The stop request signal is a signal different from the power supply request signal.

[0074] For example, the stop request signal is a signal having a greater intensity value than the power supply request signal. A large intensity value means that the amplitude or effective value of the signal is large. In this case, the frequency of the stop request signal may be, for example, the same as the frequency of the power supply request signal.

[0075] For example, the stop request signal is a signal having a different bit length from the power supply request signal. In this case, the frequency of the stop request signal may be, for example, the same as the frequency of the power supply request signal.

[0076] For example, the stop request signal is a signal having a different frequency from the power supply request signal.

[0077] The stop request signal enables the power-transmitter control unit 70 to appropriately distinguish between the power supply request signal and the stop request signal.

[0078] When the stop request signal is a signal having a different bit length from the power supply request signal, the stop request signal may be a signal having a shorter bit length than the power supply request signal. This enables the energization stop request to the power transmitter coil 22 to be notified to the power-transmitter control unit 70 as early as possible.

[0079] In step S20, when determining that the stop request condition is not satisfied, the process proceeds to step S22, where the power-receiver control device 231 instructs the generation circuit 241 to stop generating the stop request signal, and the process proceeds to step S20. As a result, the generation circuit 241 does not output the stop request signal.

[0080] After completion of step S21, the process proceeds to step S23 in which the power-receiver control device 231 determines whether power supply from the power transmitter coil 22 to the power receiver coil 102 is being executed. Specifically, the power-receiver control device 231 determines whether a period during which a current has continuously flowed through the power receiver coil 102 has exceeded a continuity threshold value since the supply of the stop request signal was started in the process of step S21. That is, it is determined whether the period during which the power receiver coil 102 has continuously received power since the stop request signal was supplied to the power-receiver communication coil 170 has exceeded the continuous threshold value. The continuous threshold value is set in advance to an appropriate value according to, for example, an expected mode of power supply to the power receiver coil 102. It may be determined whether a current flows through the power receiver coil 102 based on, for example, a current value of the power receiver coil 102 or the rectifier circuit 200 detected by the current sensor 340, or a voltage value of the power receiver coil 102 or the rectifier circuit 200 detected by the voltage sensor 330.

[0081] When it is determined in step S23 that power supply from the power transmitter coil 22 to the power receiver coil 102 is being performed, the process proceeds to step S24, and it is determined that the function of the wireless power transfer system 10 to transmit and receive the stop request signal is abnormal (malfunction). Specifically, it is determined that the function of the power-receiver communication coil 170 to transmit the stop request signal or the function of the power-transmitter communication coil 40 to receive the stop request signal is abnormal (malfunction).

[0082] Next, the process proceeds to step S25, where the power-receiver control device 231 transmits a notification signal to the vehicle ECU. The notification signal includes a signal instructing the driver of the vehicle 11 to move away from the location where power is being supplied. The place where power supply is performed is a lane or location in a parking lot, a taxi pool, a bus stop, a charging station, and the like where power is supplied to the vehicle 11 that is moving, stopped, or parked, and a lane in a road RS where multiple power transmitter coils 22 are embedded to supply power to the traveling vehicle 11, and the like.

[0083] FIG. 8 shows an example of a case where the driver is instructed to deviate from a driving lane DL1 (corresponding to power supply lane) in which multiple power transmitter coils 22 are embedded on a one-way or two-lane road RS. Specifically, the vehicle ECU that receives the notification signal causes an instrument panel of the vehicle 11 to display, for example, a message instructing the driver to deviate from the driving lane DL1. This prompts the driver to drive the vehicle 11 so as to move from the driving lane DL1 to the driving lane DL2. Then, the procedure is terminated (END). When it is determined that the function of the wireless power transfer system 10 to transmit the stop request signal is abnormal (malfunction) in the specific vehicle 11, power supply from the power transmitter coil 22 to the power receiver coil 102 is not performed in the power supply lane for the specific vehicle 11. When it is determined that the function of the wireless power transfer system 10 to transmit the stop request signal is abnormal (malfunction) in the specific vehicle 11, notification is made to notify the specific vehicle that the malfunction occurs.

[0084] On the other hand, if it is determined in step S23 that power supply from the power transmitter coil 22 to the power receiver coil 102 is not being performed, in step S26, the power-receiver control device 231 determines whether an end condition for terminating the transmission of the stop request signal is satisfied.

[0085] For example, when the stop request condition is the condition (A1), the end condition may be a condition that a state where there is no power supply request is switched to a state where there is the power supply request. That is, in the process of FIG. 5, the end condition is satisfied when the state where the determination is negative in step S10 is switched to the state where the determination is affirmative.

[0086] For example, when the stop request condition is condition (A2), the end condition may be a condition that a current no longer flows through the power receiver coil 102. It may be determined whether a current flows through the power receiver coil 102 based on, for example, a current value of the power receiver coil 102 or the rectifier circuit 200 detected by the current sensor 340, or a voltage value of the power receiver coil 102 or the rectifier circuit 200 detected by the voltage sensor 330.

[0087] For example, when the stop request condition is condition (A3) or (A4), the end condition may be a condition that the intensity value ILoud detected by the intensity sensor 350 falls below the intensity threshold value ILth. This enables to stop supplying the stop request signal when the short-range wireless communication of vehicle 500 with the excessively expanded communication range no longer reaches the vehicle 11.

[0088] When it is determined in step S26 that the end condition is satisfied, the process proceeds to step S27 where the power-receiver control device 231 instructs the generation circuit 241 to stop generating the stop request signal. Then, the procedure is terminated (END). When determination in step S26 is affirmative in a state where there is the power supply request in the process shown in the flowchart of FIG. 5, the power-receiver control device 231 instructs the generation circuit 241 to start generating the power supply request signal.

[0089] On the other hand, when it is determined in step S26 that the end condition is not satisfied, the power-receiver control device 231 executes the process again from step S23.

[0090] FIG. 9 is a flowchart of a process for energization control of the power transmitter coil 22 executed by the power- transmitter control unit 70.

[0091] In step S30, the power-transmitter control device 71 acquires determination result of whether there is the power supply request from the receiver 80. The power-transmitter control device 71 determines whether there is the power supply request based on the determination result.

[0092] In step S30, when the power-transmitter control device 71 determines that there is the power supply request, the process proceeds to step S31. In step S31, the power-transmitter control device 71 acquires from the receiver 80 the determination result of whether the stop request signal is received. The receiver 80 determines whether the stop request signal is received based on the high frequency signal input from the power-transmitter amplifier.

[0093] When determining in step S31 that the stop request signal has not been received, the process proceeds to step S32 where the power-transmitter control device 71 sets a flag F to 0. In the following step S33, the power-transmitter control device 71 performs switching control of the inverter 60 and the PFC circuit 61 to energize the power transmitter coil 22.

[0094] On the other hand, when determining in step S31 that the stop request signal is received, the process proceeds to step S34 where the power-transmitter control device 71 sets the flag F to 1. In the following step S35, the power-transmitter control device 71 stops the switching control of the inverter 60 and the PFC circuit 61 to stop energization of the power transmitter coil 22. The power-transmitter control device 71 executes the process of step S35 also when determination in step S30 is negative.

[0095] When the stop request signal is a signal having a different frequency from the power supply request signal, the carrier frequency and the modulation frequency for generating the stop request signal may be different from each other. In digital communication using a subcarrier, for example, in a case where the modulation frequency is normally set to 3.3 kHz, the power-transmitter control unit 70 may determine that the stop request signal is received, when a modulation frequency of 1 kHz is received by the power-transmitter control unit 70.

[0096] In step S36, the power-transmitter control device 71 determines whether the flag F is 1. When determining that the flag F is 0 (that is, flag F is not 1), the power-transmitter control device 71 determines that the stop request signal is not received, and the process proceeds to step S30.

[0097] On the other hand, when determining that the flag F is 1, the power-transmitter control device 71 determines that the stop request signal is received, and the process proceeds to step S37. In step S37, the power-transmitter control device 71 determines whether a release condition for releasing energization stop of the power transmitter coil 22 is satisfied. The release condition is, for example, the following condition (B1) or (B2).

[0098] (B1) A condition in which it is determined that the power supply stop request is not received, and the intensity value Intd of the power supply request signal is lower than the detection threshold value Ith. The detection threshold Ith is a value for determining whether the vehicle 500 with the excessively extended communication range is present near the vehicle 11, and is, for example, a value larger than the determination threshold Ijde.

[0099] (B2) A condition that a specified period has elapsed since determination that the power supply stop request is not received. The specified period is, for example, a period on the order of a few seconds to a few minutes. For example, the condition (B2) is used when the vehicle 11 is stopped.

[0100] When the power-transmitter control device 71 determines in step S37 that the release condition is not satisfied, the process proceeds to step S30. On the other hand, when the power-transmitter control device 71 determines that the release condition is satisfied, the process proceeds to step S38, and the power-transmitter control device 71 releases energization stop of the power transmitter coil 22. As a result, when determining that there is the power supply request, the power-transmitter control device 71 performs switching control of the inverter 60 and the PFC circuit 61 to energize the power transmitter coil 22. Then, the procedure is terminated (END).

[0101] A program for causing the wireless power transfer system 10 to execute the process shown in the flowcharts of FIGS. 7 and 9 corresponds to a wireless power transfer program. A method for causing the wireless power transfer system 10 to execute the process shown in the flowcharts of FIGS. 7 and 9 corresponds to a control method for the wireless power transfer system.

[0102] The present embodiment described above has the following advantages.

[0103] The power-receiver control unit 230 supplies the power supply request signal COMM to the power-receiver communication coil 170 and stops the supply of the power supply request signal COMM. The power-transmitter control unit 70 causes the power transmitter coil 22 to supply power to the power receiver coil 102 on condition of determination that there is the power supply request based on the power supply request signal received by the power-transmitter communication coil 40, and causes the power transmitter coil 22 to stop the power supply on condition of determination that there is no power supply request. Therefore, the power-receiver control unit 230 enables to switch between supplying power from the power transmitter coil 22 to the power receiver coil 102 and stopping the power supply by supplying the power supply request signal and stopping the supply of the power supply request signal.

[0104] The power-receiver control unit 230 supplies the stop request signal STOPCOMM, which indicates the power supply stop request with respect to the power transmitter coil 22 to stop power supply, to the power-receiver communication coil 170, when the stop request condition for requesting the power transmitter coil 22 to stop power supply is satisfied. When determining that there is the power supply stop request based on the stop request signal received by the power-transmitter communication coil 40, the power-transmitter control unit 70 stops the power supply prior to determination that there is the power supply request. Therefore, when power is supplied from the power transmitter coil 22 to the power receiver coil 102, even though no power supply is requested, the power-receiver control unit 230 enables to stop the power supply.

[0105] The power-receiver control unit 230 determines that the function of the power-receiver communication coil 170 to transmit the stop request signal or the function of the power-transmitter communication coil 40 to receive the stop request signal is abnormal, based on power supply that is performed even though the stop request signal is supplied to the power-receiver communication coil 170. Therefore, it is possible to determine that the function of the wireless power transfer system 10 to transmit and receive the stop request signal is abnormal.

[0106] The power-receiver control unit 230 determines that a function of the power-receiver communication coil 170 to transmit the stop request signal or a function of the power-transmitter communication coil 40 to receive the stop request signal is abnormal, when a period, during which the power receiver coil 102 has continuously received power since the stop request signal was supplied to the power-receiver communication coil 170, exceeds a continuous threshold. This configuration enables to easily determine occurrence of an abnormality, when the power receiver coil 102 continues to receive power, even after the power-receiver control unit 230 supplies the stop request signal to the power-receiver communication coil 170.

[0107] The power-receiver control unit 230 is capable of communicating with the vehicle ECU of the vehicle 11, which is provided with the power receiver 100, and transmits a notification signal to the vehicle ECU, when determining that the function of the power-receiver communication coil 170 to transmit the stop request signal or the function of the power-transmitter communication coil 40 to receive the stop request signal is abnormal. This configuration enables to notify occurrence of an abnormality to the vehicle ECU by the notification signal, thereby to enable to facilitate display of an indication of occurrence of an abnormality in the vehicle 11 and the like.

[0108] The notification signal includes a signal that instructs the driver of the vehicle 11 to deviate from the driving lane DL1 in which power is supplied. This configuration enables the vehicle 11 that has received the notification signal to easily display a message or the like to the driver to instruct the driver to deviate from the driving lane DL1, thereby to facilitate to encourage the driver to drive outside the driving lane DL1.

[0109] <Second Embodiment> Hereinafter, a second embodiment will be described with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, as shown in FIG. 10, the transmission process of the stop request signal is changed.

[0110] In step S20, when determining that the stop request condition is satisfied, the process proceeds to step S20A where the power-receiver control device 231 determines whether there is the power supply request from the vehicle 11. When the power-receiver control device 231 determines that there is no power supply request, the process proceeds to step S22.

[0111] On the other hand, when determining that there is the power supply request, the process proceeds to step S20B where the power-receiver control device 231 determines whether the received power Wr of the power receiver coil exceeds the requested power Weq. The received power Wr of the power receiver coil 102 may be calculated, for example, based on the current value of the power receiver coil 102 or the rectifier circuit 200 detected by the current sensor 340, or the voltage value of the power receiver coil 102 or the rectifier circuit 200 detected by the voltage sensor 330.

[0112] When determining that the received power Wr is lower (does not exceed) than the requested power Weq, the process proceeds to step S22 where the power-receiver control device 231 instructs the generation circuit 241 to stop generating the stop request signal. As a result, power is transmitted from the power transmitter coil 22 to the power receiver coil 102 of the vehicle 11 in response to the power supply request signal transmitted from the vehicle 11.

[0113] On the other hand, when determining that the received power Wr exceeds the requested power Weq, the process proceeds to step S21 where the power-receiver control device 231 instructs the generation circuit 241 to stop generating the power supply request signal and to start generating the stop request signal.

[0114] According to the present embodiment described above, when the vehicle 11 can tolerate receiving power, wireless power transfer to the vehicle 11 can be continued, even when it is determined that the stop request condition is satisfied.

[0115] <Other Embodiments> The above embodiments may be changed and carried out as follows. The same parts as those in each embodiment are denoted by the same reference numerals, and the description thereof will be incorporated herein.

[0116] Even when the power-receiver control unit 230 supplies the stop request signal to the power-receiver communication coil 170 to temporarily stop power supply, power supply may still be performed intermittently. In view of this, the process of step S23 in the flowchart of FIG. 7 may be executed in the following manner. That is, the power-receiver control device 231 determines whether an integrated value of power supplied to the power receiver coil 102 since starting supply of the stop request signal in the process of step S21, has exceeded an integrated threshold value. The integrated threshold value is set in advance to an appropriate value according to, for example, an expected mode of power supply to the power receiver coil 102. This configuration enables to determine that an abnormality occurs, when power supply is performed intermittently, and when the integrated value of the power supplied to the power receiver coil 102 exceeds the integrated threshold.

[0117] The power-receiver control unit 230 may determine that the function of the power-receiver communication coil 170 to transmit the stop request signal or the function of the power-transmitter communication coil 40 to receive the stop request signal is abnormal, when 1) the period, during which the power receiver coil 102 continuously receives power after supply of the stop request signal, exceeds a continuous threshold value, and 2) the integrated value of the power, which is supplied to the power receiver coil 102 after supply of the stop request signal, exceeds an integrated threshold value. This configuration enables to more accurately determine that power is supplied to the power receiver coil 102.

[0118] The process of step S25 in the flowchart of FIG. 7 may be modified as follows. The power-receiver control device 231 may cause the instrument panel of the vehicle 11 to display a message, which instructs the driver to leave the driving lane DL1 (corresponding to location where power is supplied), without via the vehicle ECU.

[0119] The notification signal may include a signal that instructs to display that the function of the power-receiver communication coil 170 to transmit the stop request signal is abnormal. The vehicle ECU that receives the notification signal displays, for example, a message on the instrument panel of the vehicle 11 to inform the driver that the power-receiver communication coil 170 is abnormal.

[0120] The notification signal may include a signal that instructs the vehicle 11 to automatically travel outside the driving lane DL1 (corresponding to location where power is supplied). Furthermore, the vehicle 11 may have a function of automatically traveling away from the location where power is supplied when receiving the notification signal. For example, the vehicle 11 may have a function to control the rotary electric machine 320 via the traveling inverter 310, a function to control a steering wheels via a steering device, a function to control a brake via a brake device, and the like, based on control of the vehicle ECU. This configuration enables the vehicle 11 that receives the notification signal to automatically travel outside the driving lane DL1. This enables to more reliably eliminate the state in which power is supplied from the power transmitter coil 22 to the power receiver coil 102 even though the power-receiver control unit 230 is not supplying the power supply request signal.

[0121] As shown in FIG. 11, the power receiver 100 may include in addition to the power-receiver communication coil 170 (corresponding to first power-receiver communication antenna) and the transmitter 240, a power-receiver communication coil 170A (corresponding to second power-receiver communication antenna) and a transmitter 240A. Furthermore, the power transmitter 20 may be equipped with, in addition to the power-transmitter communication coil 40 (corresponding to first power-transmitter communication antenna) and the receiver 80, a power-transmitter communication coil 40A (corresponding to second power-transmitter communication antenna) and a receiver 80A.

[0122] The power-receiver control unit 230 supplies the power supply request signal to the power-receiver communication coil 170 and stops the supply of the power supply request signal based on the processing of the flowchart in FIG. The power-transmitter control unit 70 causes the power transmitter coil 22 to supply power to the power receiver coil 102 on condition of determination that there is the power supply request based on the power supply request signal received by the power-transmitter communication coil 40, and causes the power transmitter coil 22 to stop the power supply on condition of determination that there is no power supply request. Furthermore, when determining in the process of step S20 of the flowcharts in FIGS. 7 and 10 that the stop request condition is satisfied, the power-receiver control unit 230 supplies the stop request signal to the power-receiver communication coil 170A. Based on the process of the flowchart in FIG. 9, when determining that there is the power supply stop request based on the stop request signal received by the power-transmitter communication coil 40A, the power-transmitter control unit 70 stops the power supply prior to determination that there is the power supply request.

[0123] According to the above configuration, the function to transmit the power supply request signal and to stop the transmission of the power supply request signal and the function to transmit the stop request signal and to stop the transmission of the stop request signal can be assigned to the power-receiver communication coil 170 and the power-receiver communication coil 170A, respectively. Therefore, even when an abnormality occurs in the function of the power-receiver communication coil 170 to stop the power supply request signal, the power supply from the power transmitter coil 22 to the power receiver coil 102 can be stopped by the function of the power receiver communication coil 170A to transmit the stop request signal.

[0124] However, when the function of the wireless power transfer system 10 to transmit and receive the stop request signal is abnormal, power may be supplied from the power transmitter coil 22 to the power receiver coil 102 even when no power supply request is made. In view of this, the power-receiver control unit 230 determines that the function of the power-receiver communication coil 170A to transmit the stop request signal or the function of the power-transmitter communication coil 40A to receive the stop request signal is abnormal, based on power supply that is performed even though the stop request signal is supplied to the power-receiver communication coil 170A. Therefore, it is possible to determine that the function of the wireless power transfer system 10 to transmit and receive the stop request signal is abnormal.

[0125] In addition, the function to receive the power supply request signal and the function to receive the stop request signal can be assigned to the power-transmitter communication coil 40 and the power-transmitter communication coil 40A, respectively. Therefore, even when an abnormality occurs in the function of the power-transmitter communication coil 40 to recognize stop of the power supply request signal, the power supply from the power transmitter coil 22 to the power receiver coil 102 can be stopped by the function of the power-transmitter communication coil 40A to receive the stop request signal.

[0126] The wireless power transfer system 10 in FIG. 11 may be modified as shown in FIG. 12. That is, the power receiver 100 includes the power-receiver communication coil 170 and the transmitter 240, but does not include the power-receiver communication coil 170A and the transmitter 240A. In this case, the power-receiver control unit 230 supplies the power supply request signal to the power-receiver communication coil 170 and stops the supply of the power supply request signal based on the processing of the flowchart in FIG. 5. The power-transmitter control unit 70 causes the power transmitter coil 22 to supply power to the power receiver coil 102 on condition of determination that there is the power supply request based on the power supply request signal received by the power-transmitter communication coil 40, and causes the power transmitter coil 22 to stop the power supply on condition of determination that there is no power supply request. Furthermore, when determining in the process of step S20 of the flowcharts in FIGS. 7 and 10 that the stop request condition is satisfied, the power-receiver control unit 230 supplies the stop request signal to the power-receiver communication coil 170. Based on the process of the flowchart in FIG. 9, when determining that there is the power supply stop request based on the stop request signal received by the power-transmitter communication coil 40A, the power-transmitter control unit 70 stops the power supply prior to determination that there is the power supply request.

[0127] In the above configuration, the function to receive the power supply request signal and the function to receive the stop request signal can be assigned to the power-transmitter communication coil 40 and the power-transmitter communication coil 40A, respectively. Therefore, even when an abnormality occurs in the function of the power-transmitter communication coil 40 to recognize stop of the power supply request signal, the power supply from the power transmitter coil 22 to the power receiver coil 102 can be stopped by the function of the power-transmitter communication coil 40A to receive the stop request signal.

[0128] The wireless power transfer system 10 in FIG. 11 may be modified as shown in FIG. 13. That is, the power transmitter 20 includes the power-transmitter communication coil 40 and the receiver 80, but does not include the power-transmitter communication coil 40A and the receiver 80A. In this case, the power-receiver control unit 230 supplies the power supply request signal to the power-receiver communication coil 170 and stops the supply of the power supply request signal based on the processing of the flowchart in FIG. 5. The power-transmitter control unit 70 causes the power transmitter coil 22 to supply power to the power receiver coil 102 on condition of determination that there is the power supply request based on the power supply request signal received by the power-transmitter communication coil 40, and causes the power transmitter coil 22 to stop the power supply on condition of determination that there is no power supply request. Furthermore, when determining in the process of step S20 of the flowcharts in FIGS. 7 and 10 that the stop request condition is satisfied, the power-receiver control unit 230 supplies the stop request signal to the power-receiver communication coil 170A. Based on the process of the flowchart in FIG. 9, when determining that there is the power supply stop request based on the stop request signal received by the power-transmitter communication coil 40, the power-transmitter control unit 70 stops the power supply prior to determination that there is the power supply request.

[0129] According to the above configuration, the function to transmit the power supply request signal and to stop the transmission of the power supply request signal and the function to transmit the stop request signal and to stop the transmission of the stop request signal can be assigned to the power-receiver communication coil 170 and the power-receiver communication coil 170A, respectively. Therefore, even when an abnormality occurs in the function of the power receiver communication coil 170 to stop the power supply request signal, the power supply from the power transmitter coil 22 to the power receiver coil 102 can be stopped by the function of the receiving side communication coil 170A to transmit the stop request signal. The power-receiver control unit 230 determines that the function of the power-receiver communication coil 170A to transmit the stop request signal or the function of the power-transmitter communication coil 40 to receive the stop request signal is abnormal, based on power supply that is performed even though the stop request signal is supplied to the power-receiver communication coil 170A. Therefore, it is possible to determine that the function of the wireless power transfer system 10 to transmit and receive the stop request signal is abnormal.

[0130] In the power receiver 100 in FIGS. 11 and 13, the power-receiver communication coil 170 and the power-receiver communication coil 170A may transmit the stop request signal. In the power transmitter 20 in FIGS. 11 and 12, the power-transmitter communication coil 40 and the power-transmitter communication coil 40A may receive the stop request signal.

[0131] As shown by the solid line in FIG. 14, the power-transmitter communication coil 40A (corresponding to second power-transmitter communication antenna) in FIGS. 11 and 12 may be, for example, buried (installed) in an outer edge of the road RS in the driving lane DL1. In a case where the power-transmitter communication coil 40A is configured to receive the power supply request signal and the stop request signal, this configuration enables to prevent the power-transmitter communication coil 40A from receiving the power supply request signal transmitted from a vehicle traveling in the travel lane DL2. As shown by the dashed line in FIG. 14, the power-transmitter communication coil 40A may be buried in the end of the driving lane DL1 on the center side of the road RS, or may be buried near the center of the driving lane DL1. In addition, the power-transmitter communication coil 40A may be of the same size as the power-transmitter communication coil 40 and installed as one for each power transmitter coil 22, or multiple coils smaller than the power-transmitter communication coil 40 may be installed for each power transmitter coil 22.

[0132] The power-transmitter communication coil 40A may be modified to include a passive element such as a coil, a capacitor, and an LED, without including the power source. The LED may be turned on by an induced electromotive force generated when the stop request signal is input to the coil, thereby notifying the driver that the power receiver 100 is transmitting the stop request signal.

[0133] The power-receiver communication antenna and the power-transmitter communication antenna are not limited to communication coils, and may employ various antennas.

[0134] The method of wireless power transmission by the power transmitter antenna and the power receiver antenna is not limited to the magnetic field resonance method, and may be an electric field coupling method. In this case, a power transmitter antenna and a power receiver antenna that are different in form from coils and use an electric field coupling method may be used.

[0135] In the wireless power transfer system 10, the power transmitter 20 may perform wide-area wireless communication with the power receiver 100. Wide area wireless communication is a communication with a longer communication distance than the narrow area wireless communication. Examples of the wide area wireless communication include 3GPP (registered trademark), 4G, LTE, 5G, and WiMAX (registered trademark) developed by IEEE. The power-transmitter control unit 70 and the power-receiver control unit 230 may transmit and receive information using the wide area wireless communication. Furthermore, when determining that the function of the power-receiver communication coil 170 and 170A to transmit the stop request signal or the function of the power-transmitter communication coil 40 and 40A to receive the stop request signal is abnormal, the power-receiver control unit 230 may transmit a power supply stop signal to the power transmitter 20 to stop power supply. When receiving the power supply stop signal from the power-transmitter communication coil 40 and 40A, the power-transmitter control unit 70 may stop the power supply by giving priority to the determination that there is the power supply request. This configuration enables, by using wide area wireless communication, to stop power supply to the power transmitter 20 even when the power transmitter 20 is away from the vehicle 11 while the vehicle 11 is traveling.

[0136] The power-transmitter control unit 70 and the power-receiver control unit 230 (wireless power transfer system 10) and the method thereof described in the present disclosure may be implemented by a special purpose computer which is configured with a memory and a processor programmed to execute one or more particular functions embodied in computer programs of the memory. Alternatively, the power-transmitter control unit 70 and the power-receiver control unit 230 and the method thereof described in the present disclosure may be implemented by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the power-transmitter control unit 70 and the power-receiver control unit 230 and the method thereof described in the present disclosure may be implemented by one or more dedicated computers constituted by a combination of the processor and the memory programmed to execute one or more functions and the processor with one or more hardware logic circuits. The computer programs may be stored, as instructions to be executed by a computer, in a tangible non-transitory computer-readable medium.

[0137] The present disclosure has been described based on examples, but it is understood that the present disclosure is not limited to the examples or structures. The present disclosure also encompasses various modifications and variations within the scope of equivalents. Furthermore, although various combinations and modes are described in the present disclosure, the scope and idea of the present disclosure further include other combinations and modes including only one element, more elements, or less elements in these.

[0138] The above-described embodiments and the modified examples may be combined to a possible extent.

[0139] Characteristic configurations extracted from each of the above-described embodiments will be described below.

[0140] As follows, characteristic configurations of the above-described embodiments will be described. (Configuration 1) A power receiver device is to be applied to a wireless power transfer system (10). The wireless power transfer system includes: a power transmitter device (20) including a power transmitter antenna (22), at least one power-transmitter communication antenna (40, 40A), and a power-transmitter control unit (70); and the power receiver device (100). The power receiver device (100) includes: a power receiver antenna (102) configured to wirelessly receive power from the power transmitter antenna; at least one power-receiver communication antenna (170, 170A) configured to wirelessly communicate with the power-transmitter communication antenna; and a power-receiver control unit (230). The power-receiver control unit is configured to supply a power supply request signal, which indicates power supply request to the power transmitter antenna, to the power-receiver communication antenna, and stop supply of the power supply request signal. The power-transmitter control unit is configured to, based on the power supply request signal received by the power-transmitter communication antenna, cause the power transmitter antenna to supply power to the power receiver antenna when determining that there is the power supply request, and stop power supply when determining that there is no power supply request. The receiver control unit is configured to supply a stop request signal, which indicates power supply stop request for requesting the power transmitter antenna to stop power supply, to the power-receiver communication antenna, when a specified stop condition, which is for requesting the power transmitter antenna to stop power supply, is satisfied. The power-transmitter control unit is configured to stop power supply, prior to determination that there is the power supply request, when determining that there is the power supply stop request based on the stop request signal received by the power-transmitter communication antenna. The receiver control unit is configured to determine that a function of the power-receiver communication antenna to transmit the stop request signal or a function of the power-transmitter communication antenna to receive the stop request signal is abnormal, based on power supply that is performed even though supplying the stop request signal to the power-receiver communication antenna. (Configuration 2) The power receiver device according to the configuration 1, in which the power-receiver communication antenna includes a first power-receiver communication antenna (170) and a second power-receiver communication antenna (170A), the power-receiver control unit is configured to supply the power supply request signal to the first power-receiver communication antenna and stop supply of the power supply request signal, the power-receiver control unit is configured to supply the stop request signal to the second power-receiver communication antenna when the specified stop condition is satisfied, and the receiver control unit is configured to determine that a function of the second power-receiver communication antenna to transmit the stop request signal or the function of the power-transmitter communication antenna to receive the stop request signal is abnormal, based on power supply that is performed even though supplying the stop request signal to the second power-receiver communication antenna. (Configuration 3) The power receiver device according to the configuration 1 or 2, in which the receiver control unit is configured to determine that the function of the power-receiver communication antenna to transmit the stop request signal or the function of the power-transmitter communication antenna to receive the stop request signal is abnormal, when a period, during which the power receiver antenna continues to receive power after supplying the stop request signal to the power-receiver communication antenna, exceeds a continuous threshold. (Configuration 4) The power receiver device according to any one of the configurations 1 to 3, in which the receiver control unit is configured to determine that the function of the power-receiver communication antenna to transmit the stop request signal or the function of the power-transmitter communication antenna to receive the stop request signal is abnormal, when an integrated value of power, which is supplied to the power receiver antenna after supplying the stop request signal to the power-receiver communication antenna, exceeds an integrated threshold. (Configuration 5) The power receiver device according to any one of the configurations 1 to 4, in which the power-receiver control unit is capable of performing wide area wireless communication with the power transmitter device, and configured to transmit a power supply stop signal, which is to stop power supply, to the power transmitter device, when determining that the function of the power-receiver communication antenna to transmit the stop request signal or the function of the power-transmitter communication antenna to receive the stop request signal is abnormal. (Configuration 6) The power receiver device according to any one of the configurations 1 to 5, in which the power-receiver control unit is capable of communicating with a vehicle (11) equipped with the power receiver device, and configured to transmit a notification signal to the vehicle, when determining that the function of the power-receiver communication antenna to transmit the stop request signal or the function of the power-transmitter communication antenna to receive the stop request signal is abnormal. (Configuration 7) The power receiver device according to the configuration 6, in which the notification signal includes a signal for instructing a driver of the vehicle to move away from a location where power supply is performed. (Configuration 8) A vehicle equipped with the power receiver device according to the configuration 6 or 7, in which the notification signal includes a signal for instructing the vehicle to automatically travel away from a location where power supply is performed, and the vehicle has a function to automatically travel away from the location where power supply is performed when receiving the notification signal.

Claims

1. A power receiver device to be applied to a wireless power transfer system (10), the wireless power transfer system including: a power transmitter device (20) including a power transmitter antenna (22), at least one power-transmitter communication antenna (40, 40A), and a power-transmitter control unit (70); and the power receiver device (100), the power receiver device (100) comprising: a power receiver antenna (102) configured to wirelessly receive power from the power transmitter antenna; at least one power-receiver communication antenna (170, 170A) configured to wirelessly communicate with the power-transmitter communication antenna; and a power-receiver control unit (230), wherein the power-receiver control unit is configured to supply a power supply request signal, which indicates power supply request to the power transmitter antenna, to the power-receiver communication antenna, and stop supply of the power supply request signal, the power-transmitter control unit is configured to, based on the power supply request signal received by the power-transmitter communication antenna, cause the power transmitter antenna to supply power to the power receiver antenna when determining that there is the power supply request, and stop power supply when determining that there is no power supply request, the receiver control unit is configured to supply a stop request signal, which indicates power supply stop request for requesting the power transmitter antenna to stop power supply, to the power-receiver communication antenna, when a specified stop condition, which is for requesting the power transmitter antenna to stop power supply, is satisfied, the power-transmitter control unit is configured to stop power supply, prior to determination that there is the power supply request, when determining that there is the power supply stop request based on the stop request signal received by the power-transmitter communication antenna, and the receiver control unit is configured to determine that a function of the power-receiver communication antenna to transmit the stop request signal or a function of the power-transmitter communication antenna to receive the stop request signal is abnormal, based on power supply that is performed even though supplying the stop request signal to the power-receiver communication antenna.

2. The power receiver device according to claim 1, wherein the power-receiver communication antenna includes a first power-receiver communication antenna (170) and a second power-receiver communication antenna (170A), the power-receiver control unit is configured to supply the power supply request signal to the first power-receiver communication antenna and stop supply of the power supply request signal, the power-receiver control unit is configured to supply the stop request signal to the second power-receiver communication antenna when the specified stop condition is satisfied, and the receiver control unit is configured to determine that a function of the second power-receiver communication antenna to transmit the stop request signal or the function of the power-transmitter communication antenna to receive the stop request signal is abnormal, based on power supply that is performed even though supplying the stop request signal to the second power-receiver communication antenna.

3. The power receiver device according to claim 1 or 2, wherein the receiver control unit is configured to determine that the function of the power-receiver communication antenna to transmit the stop request signal or the function of the power-transmitter communication antenna to receive the stop request signal is abnormal, when a period, during which the power receiver antenna continues to receive power after supplying the stop request signal to the power-receiver communication antenna, exceeds a continuous threshold.

4. The power receiver device according to claim 1 or 2, wherein the receiver control unit is configured to determine that the function of the power-receiver communication antenna to transmit the stop request signal or the function of the power-transmitter communication antenna to receive the stop request signal is abnormal, when an integrated value of power, which is supplied to the power receiver antenna after supplying the stop request signal to the power-receiver communication antenna, exceeds an integrated threshold.

5. The power receiver device according to claim 1 or 2, wherein the power-receiver control unit is capable of performing wide area wireless communication with the power transmitter device, and configured to transmit a power supply stop signal, which is to stop power supply, to the power transmitter device, when determining that the function of the power-receiver communication antenna to transmit the stop request signal or the function of the power-transmitter communication antenna to receive the stop request signal is abnormal.

6. The power receiver device according to claim 1 or 2, wherein the power-receiver control unit is capable of communicating with a vehicle (11) equipped with the power receiver device, and configured to transmit a notification signal to the vehicle, when determining that the function of the power-receiver communication antenna to transmit the stop request signal or the function of the power-transmitter communication antenna to receive the stop request signal is abnormal.

7. The power receiver device according to claim 6, wherein the notification signal includes a signal for instructing a driver of the vehicle to move away from a location where power supply is performed.

8. A vehicle equipped with the power receiver device according to claim 6, wherein the notification signal includes a signal for instructing the vehicle to automatically travel away from a location where power supply is performed, and the vehicle has a function to automatically travel away from the location where power supply is performed when receiving the notification signal.

9. A wireless power transfer system (10) comprising: a power transmitter device (20) including a power transmitter antenna (22), at least one power-transmitter communication antenna (40, 40A), and a power-transmitter control unit (70); and a power receiver device (100) including a power receiver antenna (102) configured to wirelessly receive power from the power transmitter antenna, at least one power-receiver communication antenna (170, 170A) configured to wirelessly communicate with the power-transmitter communication antenna, and a power-receiver control unit (230), wherein the power-receiver control unit is configured to supply a power supply request signal, which indicates power supply request to the power transmitter antenna, to the power-receiver communication antenna, and stop supply of the power supply request signal, the power-transmitter control unit is configured to, based on the power supply request signal received by the power-transmitter communication antenna, cause the power transmitter antenna to supply power to the power receiver antenna when determining that there is the power supply request, and stop power supply when determining that there is no power supply request, the receiver control unit is configured to supply a stop request signal, which indicates power supply stop request for requesting the power transmitter antenna to stop power supply, to the power-receiver communication antenna, when a specified stop condition, which is for requesting the power transmitter antenna to stop power supply, is satisfied, the power-transmitter control unit is configured to stop power supply, prior to determination that there is the power supply request, when determining that there is the power supply stop request based on the stop request signal received by the power-transmitter communication antenna, and the receiver control unit is configured to determine that a function of the power-receiver communication antenna to transmit the stop request signal or a function of the power-transmitter communication antenna to receive the stop request signal is abnormal, based on power supply that is performed even though supplying the stop request signal to the power-receiver communication antenna.

10. The wireless power transfer system according to claim 9, wherein the power-transmitter communication antenna includes a first power-transmitter communication antenna (40) and a second power-transmitter communication antenna (40A), the power-transmitter control unit is configured to, based on the power supply request signal received by the first power-transmitter communication antenna, cause the power transmitter antenna to supply power to the power receiver antenna when determining that there is the power supply request, and stop power supply when determining that there is no power supply request, and the power-transmitter control unit is configured to stop power supply, prior to determination that there is the power supply request, when determining that there is the power supply stop request based on the stop request signal received by the second power-transmitter communication antenna.

11. The wireless power transfer system according to claim 9 or 10, wherein the power-receiver control unit is capable of performing wide area wireless communication with the power transmitter device, configured to transmit a power supply stop signal, which is to stop power supply, to the power transmitter device, when determining that the function of the power-receiver communication antenna to transmit the stop request signal or the function of the power-transmitter communication antenna to receive the stop request signal is abnormal, and the power-transmitter control unit is configured to stop power supply prior to determination that there is the power supply request, when receiving the power supply stop signal by the power-transmitter communication antenna.

12. A wireless power transfer program to be applied to a wireless power transfer system (10) including: a power transmitter device (20) including a power transmitter antenna (22), a power-transmitter communication antenna (40, 40A), and a power-transmitter control unit (70); and a power receiver device (100) including a power receiver antenna (102) configured to wirelessly receive power from the power transmitter antenna, at least one power-receiver communication antenna (170, 170A) configured to wirelessly communicate with the power-transmitter communication antenna, and a power-receiver control unit (230), the wireless power transfer program configured to carry out: executing a process to cause the power-receiver control unit to supply a power supply request signal, which indicates power supply request to the power transmitter antenna, to the power-receiver communication antenna, and stop supply of the power supply request signal; executing a process to cause the power-transmitter control unit to, based on the power supply request signal received by the power-transmitter communication antenna, cause the power transmitter antenna to supply power to the power receiver antenna when determining that there is the power supply request, and stop power supply when determining that there is no power supply request; executing a process to cause the receiver control unit to supply a stop request signal, which indicates power supply stop request for requesting the power transmitter antenna to stop power supply, to the power-receiver communication antenna, when a specified stop condition, which is for requesting the power transmitter antenna to stop power supply, is satisfied; executing a process to cause the power-transmitter control unit to stop power supply, prior to determination that there is the power supply request, when determining that there is the power supply stop request based on the stop request signal received by the power-transmitter communication antenna; and executing a process to cause the receiver control unit to determine that a function of the power-receiver communication antenna to transmit the stop request signal or a function of the power-transmitter communication antenna to receive the stop request signal is abnormal, based on power supply that is performed even though supplying the stop request signal to the power-receiver communication antenna.

13. A control method for a wireless power transfer system (10) including: a power transmitter device (20) including a power transmitter antenna (22), a power-transmitter communication antenna (40, 40A), and a power-transmitter control unit (70); and a power receiver device (100) including a power receiver antenna (102) configured to wirelessly receive power from the power transmitter antenna, at least one power-receiver communication antenna (170, 170A) configured to wirelessly communicate with the power-transmitter communication antenna, and a power-receiver control unit (230), the control method comprising: executing a process to cause the power-receiver control unit to supply a power supply request signal, which indicates power supply request to the power transmitter antenna, to the power-receiver communication antenna, and stop supply of the power supply request signal; executing a process to cause the power-transmitter control unit to, based on the power supply request signal received by the power-transmitter communication antenna, cause the power transmitter antenna to supply power to the power receiver antenna when determining that there is the power supply request, and stop power supply when determining that there is no power supply request; executing a process to cause the receiver control unit to supply a stop request signal, which indicates power supply stop request for requesting the power transmitter antenna to stop power supply, to the power-receiver communication antenna, when a specified stop condition, which is for requesting the power transmitter antenna to stop power supply, is satisfied; executing a process to cause the power-transmitter control unit to stop power supply, prior to determination that there is the power supply request, when determining that there is the power supply stop request based on the stop request signal received by the power-transmitter communication antenna; and executing a process to cause the receiver control unit to determine that a function of the power-receiver communication antenna to transmit the stop request signal or a function of the power-transmitter communication antenna to receive the stop request signal is abnormal, based on power supply that is performed even though supplying the stop request signal to the power-receiver communication antenna.

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