JP6248883B2 - Power receiving device - Google Patents

Description

  The present invention relates to a power reception device, and more particularly, to a power reception device including a power reception unit that can receive power from a power transmission device in a contactless manner and charge a battery, and a control unit that controls the power reception unit.

  Conventionally, as a power receiving device that is mounted on a vehicle and can receive power from a power transmission device in a non-contact manner and charge the power storage device, a power receiving unit having a power receiving coil and AC power received by the power receiving unit are converted into DC power. Alignment with one terminal connected to the rectifier circuit that outputs to the power storage device side, the charge relay that connects and disconnects the rectifier circuit and the power storage device, and the positive line between the rectifier circuit and the charge relay And an alignment relay that connects and disconnects the negative electrode side line between the rectifier circuit and the charging relay and the other terminal of the load resistor has been proposed ( For example, see Patent Document 1).

  In a non-contact power transmission / reception system including a power reception device configured in this manner and a power transmission device including a power transmission unit having a power transmission coil, before starting full-scale charging of the power storage device, a charging relay of the power reception device is set. While turning off and turning on the positioning relay, weak power as a test signal is transmitted from the power transmission unit of the power transmission device to the power reception unit of the power reception device. In addition, when charging the power storage device by non-contact power transmission / reception between the power transmission unit of the power transmission device and the power reception unit of the power reception device, the relay for positioning the power reception device is turned off and the charging relay is turned on to transmit power. A predetermined power is transmitted from the power transmission unit of the device to the power reception unit of the power reception device, and the power is rectified by a rectifier circuit and supplied to the power storage device.

JP 2013-135572 A

  In such a power receiving device, while the charging relay is turned on and the position detection relay is turned off, any abnormality occurs while the power storage device is being charged with the power transmitted from the power transmitting unit of the power transmitting device to the power receiving unit of the power receiving device. If this occurs, the charging relay may be turned off in order to stop charging the power storage device. At this time, if the charging relay is simply turned off, the impedance of the power receiving device as seen from the power transmitting device changes greatly, and a part of the transmitted power (relatively large power) from the power transmitting device is reflected by the power receiving device to the power transmitting device. May return. If this reflected power is large, the power factor of the power transmission device may be greatly deteriorated. In addition, when the reflected power is large, it is necessary to secure a large margin for the reflected power when designing the power transmission device by setting the withstand voltage and the withstand current of the power transmission device.

  The power receiving device according to the present invention reflects the reflected power by the power receiving device with respect to the power from the power transmitting device when any abnormality occurs while the battery is being charged by receiving power from the power transmitting device without contact and charging the battery. The main purpose is to reduce the size.

  The power receiving device of the present invention employs the following means in order to achieve the main object described above.

  The power receiving device of the present invention includes a power receiving unit that can receive power from the power transmitting device in a non-contact manner and charge the battery, and a control unit that controls the power receiving unit. The power receiving unit includes a resonance circuit having a power receiving coil for receiving power from a power transmission coil of the power transmission device in a non-contact manner, and charging for supplying AC power to the battery by converting AC power received by the resonance circuit into DC power A first relay that connects and disconnects the circuit, the battery and the resonant circuit; and a first relay connected between the resonant circuit and the first relay and in parallel with the resonant circuit and in series with each other. 2 relays and resistors. The control means turns off the second relay and turns on the first relay, and when an abnormality occurs in the power receiving unit during charging of the battery by power transmitted from the power transmission device to the power receiving unit. The first relay is turned off after the second relay is turned on.

  In this power receiving device of the present invention, when an abnormality occurs in the power receiving unit while the second relay of the power receiving unit is turned off and the first relay is turned on and the battery is being charged by the power transmitted from the power transmitting device to the power receiving unit. Then, after turning on the second relay, the first relay is turned off to stop charging the battery. As a result, when an abnormality occurs in the power receiving unit during charging of the battery, the first relay is turned off as compared with the case where the first relay is turned off without turning on the second relay. The change in the impedance of the power receiving device viewed from the power transmission device at the time (when charging of the battery is stopped) can be suppressed, and the reflected power by the power receiving device with respect to the transmitted power from the power transmission device can be reduced. As a result, it is possible to suppress the power factor of the power transmission device from greatly deteriorating. Further, when the power transmission device is designed by determining the withstand voltage and current resistance of the power transmission device, the margin for the reflected power can be set small. Here, as “abnormality of the power receiving unit”, when the transmitted power of the power transmitting apparatus is equal to or higher than the first power threshold and the received power of the power receiving apparatus is less than the second threshold smaller than the first power threshold, the transmitted power of the power transmitting apparatus When the power difference between the power and the power received by the power receiving apparatus is equal to or greater than the power difference threshold, the temperature of the resonance circuit is equal to or higher than the first temperature threshold, the battery temperature is equal to or higher than the second temperature threshold, and the like.

It is a block diagram which shows the outline of a structure of the non-contact power transmission / reception system 10 provided with the power receiving apparatus as one Example of this invention. It is a block diagram which shows the outline of a structure of the non-contact power transmission / reception system 10 provided with the power receiving apparatus as one Example of this invention. It is a block diagram which shows the outline of a structure of the motor vehicle 20B of a modification.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 and FIG. 2 are configuration diagrams showing an outline of the configuration of a non-contact power transmission / reception system 10 including a power receiving device as one embodiment of the present invention. As shown in FIGS. 1 and 2, the non-contact power transmission / reception system 10 according to the embodiment receives power from the power transmission device 130 installed in a parking lot or the like, the battery 26 and the power transmission device 130 and charges the battery 26. And an automobile 20 on which the power receiving device 30 is mounted.

  The power transmission device 130 includes a power transmission unit 131 connected to an AC power source 190 such as a household power source (for example, 200 V, 50 Hz), and a power transmission electronic control unit (hereinafter referred to as “power transmission ECU”) 170 that controls the power transmission unit 131. And a communication unit 180 that communicates with the power transmission ECU 170 and wirelessly communicates with a communication unit 80 (described later) of the automobile 20.

  The power transmission unit 131 includes a power transmission resonance circuit 132 and a high-frequency power circuit 140 provided between the AC power supply 190 and the power transmission resonance circuit 132. Here, the power transmission resonance circuit 132 includes a power transmission coil 134 installed on a floor surface of a parking lot, and a capacitor 136 connected in series to the power transmission coil 134. The power transmission resonance circuit 132 is designed such that the resonance frequency is a predetermined frequency Fset (several tens to several hundreds kHz). The high frequency power supply circuit 140 is configured as a circuit that converts power from the AC power supply 190 into power having a predetermined frequency Fset and outputs the power to the power transmission resonance circuit 132, and includes a filter, a frequency conversion circuit, a leakage breaker, and the like.

  Although not shown, power transmission ECU 170 is configured as a microprocessor centered on a CPU, and includes a ROM for storing processing programs, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The power transmission ECU 170 detects by converting the current Itr of the power transmission resonance circuit 132 from the current sensor 150 that detects the AC current flowing in the power transmission resonance circuit 132 and the AC voltage between the terminals of the power transmission resonance circuit 132 into a DC voltage. The voltage (transmission voltage) Vtr between terminals of the resonance circuit 132 for power transmission from the voltage detection unit 152 to be input is input via the input port. The voltage detection unit 152 includes a rectifier circuit and a voltage sensor. From the power transmission ECU 170, a control signal to the high-frequency power supply circuit 140 is output via an output port.

  The automobile 20 is configured as an electric vehicle, and includes a traveling motor 22, an inverter 24 for driving the motor 22, a battery 26 that exchanges electric power with the motor 22 via the inverter 24, and the inverter 24 and the battery. 26, a system main relay 28, a power receiving unit 31 connected to the battery 26, a vehicle electronic control unit (hereinafter referred to as “vehicle ECU”) 70 for controlling the entire vehicle, and a vehicle ECU 70. And a communication unit 80 that communicates with the communication unit 180 of the power transmission device 130 and performs wireless communication.

  The power receiving unit 31 includes a power receiving resonance circuit 32, a charging circuit 40 provided between the power receiving resonance circuit 32 and the battery 26, and a charging circuit provided between the power receiving resonance circuit 32 and the charging circuit 40. The relay 42 includes a relay 44 and a resistor 46 that are connected between the power receiving resonance circuit 32 and the charging relay 42 and in parallel with the power receiving resonance circuit and in series with each other. Here, the power receiving resonance circuit 32 includes a power receiving coil 34 installed on the bottom surface (floor panel) of the vehicle body, and a capacitor 36 connected in series to the power receiving coil 34. The power receiving resonance circuit 32 is designed such that the resonance frequency becomes a frequency (ideally, the predetermined frequency Fset) near the predetermined frequency Fset (resonance frequency of the power transmission resonance circuit 132). The charging circuit 40 is configured as a circuit capable of converting AC power received by the power receiving resonance circuit 32 into DC power and supplying the DC power to the battery 26, and includes a rectifier circuit, a smoothing circuit, and the like. The charging relay 42 connects and disconnects the power receiving resonance circuit 32 side and the charging circuit 42 side. The relay 44 is a resistor having one terminal connected to a positive line between the power receiving resonance circuit 32 and the charging relay 42 and a negative line between the power receiving resonance circuit 32 and the charging relay 42. Connection to and release from the other terminal.

  Although not shown, the vehicle ECU 70 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The vehicle ECU 70 detects the rotational position θm of the rotor of the motor 22 from the rotational position detection sensor that detects the rotational position of the rotor of the motor 22 and the current that detects the phase current flowing in each phase of the three-phase coil of the motor 22. Phase currents Iu, Iv, Iw from the sensor, a battery voltage Vb from a voltage sensor 27a installed between terminals of the battery 26, a battery current Ib from a current sensor 27b attached to a positive terminal of the battery 26, and the battery 26 The battery temperature Tb from the temperature sensor 27c that detects the temperature of the battery is input via the input port. The vehicle ECU 70 also includes an ignition signal from an ignition switch (start switch), a shift position SP from a shift position sensor that detects the operation position of the shift lever, and an accelerator from an accelerator pedal position sensor that detects the amount of depression of the accelerator pedal. The opening degree Acc, the brake pedal position BP from the brake pedal position sensor that detects the depression amount of the brake pedal, and the vehicle speed V from the vehicle speed sensor are input via the input port. Further, the vehicle ECU 70 supplies the current Ire of the power receiving resonance circuit 32 from the current sensor 50 that detects the alternating current flowing in the power receiving resonance circuit 32, the voltage between the terminals of the power receiving resonance circuit 32 from the voltage detection unit 52 (power reception). Voltage) Vre1, the voltage Vre2 between the input sides of the charging circuit 40 from the voltage detection unit 54, the voltage Vre3 between the terminals of the resistor 46 from the voltage detection unit 56, and the substrate mounted with the power receiving resonance circuit 32. The temperature Tre of the power receiving resonance circuit 32 from the temperature sensor 58 is input via the input port. The voltage detection unit 52 includes a rectifier circuit that converts an AC voltage between terminals of the power receiving resonance circuit 32 into a DC voltage, and a voltage sensor that detects the converted DC voltage. The voltage detection unit 54 is provided between the charging circuit 40 and the charging relay 42 and converts an AC voltage between the positive electrode side line and the negative electrode side line (voltage between terminals on the input side of the charging circuit 40) into a DC voltage. A rectifier circuit; and a voltage sensor that detects the converted DC voltage. The voltage detection unit 56 includes a rectifier circuit that converts an AC voltage between the terminals of the resistor 46 into a DC voltage, and a voltage sensor that detects the converted DC voltage. From the vehicle ECU 70, a switching control signal to a switching element (not shown) of the inverter 24, an on / off signal to the system main relay 28, an on / off signal to the charging relay 42, an on / off signal to the relay 44, and the like are output via an output port. Has been. The vehicle ECU 70 calculates the storage ratio SOC of the battery 26 based on the integrated value of the battery current Ib of the battery 26 detected by the current sensor 27b.

  Here, in the embodiment, the power receiving device 30 mainly corresponds to the power receiving unit 31, the vehicle ECU 70, and the communication unit 80.

  In the non-contact power transmission / reception system 10 of the embodiment configured as described above, the power transmission coil 134 of the power transmission resonance circuit 132 and the power reception coil 34 of the power reception resonance circuit 32 are close to each other, and the charging relay 42 or the relay 44. When the power of the predetermined frequency Fset is supplied from the AC power supply 190 to the power transmission resonance circuit 132 via the high frequency power supply circuit 140 when the power is turned on, the power transmission coil 134 and the power reception coil 34 generate an electromagnetic field. Energy (electric power) is transmitted from the power transmission coil 134 to the power reception coil 34. The energy transmission by the resonance is performed when the Q value indicating the resonance intensity between the power transmission coil 134 and the power reception coil 34 is equal to or greater than a predetermined value Qref (for example, 100).

  In the non-contact power transmission / reception system 10, when the vehicle 20 travels, the vehicle ECU 70 causes the accelerator opening Acc and the engine opening degree Acc and the charging relay 42 and the relay 44 to be off while the system main relay 28 is on. The vehicle travels by switching the switching element of the inverter 24 so that the motor 22 is driven by the required torque Tr * for traveling set according to the vehicle speed V.

  In addition, the automobile 20 outputs a request for charging the battery 26 from the vehicle ECU 70 via the communication unit 80 during traveling. When power transmission ECU 170 receives a request for charging battery 26 via communication unit 180, communication is started between power transmission ECU 170 and vehicle ECU 70 via communication units 180 and 80. After the communication between the power transmission ECU 170 and the vehicle ECU 170 is started in this way, the automobile 20 is suitable for non-contact charging in which the battery 26 is charged with electric power transmitted from the power transmission unit 131 to the power reception unit 31 in a parking lot or the like. When the vehicle ECU 70 approaches the contactless charging position (position where the power transmission coil 134 of the power transmission resonance circuit 132 and the power reception coil 34 of the power reception resonance circuit 32 substantially face each other) to some extent, the vehicle ECU 70 turns on the relay 44, The power transmission ECU 170 starts control of the high-frequency power circuit 140 so that weak power is supplied to the power transmission coil 134. In general, as the power transmission coil 134 and the power reception coil 34 approach each other, the power transmitted from the power transmission coil 134 to the power reception coil 34 increases, and the power supplied to the resistor 46 increases. Therefore, the distance between the power transmission coil 134 and the power reception coil 34 can be estimated by using the voltage Vre3 between the terminals of the resistor 46 detected by the voltage detection unit 56. Then, the vehicle ECU 70 determines the power transmission coil 134 based on the inter-terminal voltage Vre3 of the resistor 46 and an image of the surroundings of the automobile 20 taken by a camera (not shown) so that the automobile 20 stops at the non-contact charging position. The positional relationship (distance and direction) with the power receiving coil 34 is estimated, and this positional relationship is displayed on a display of a navigation device (not shown) to guide the vehicle 20 to approach the contactless charging position. .

  Thus, when the automobile 20 stops (parks) near the non-contact charging position and the ignition is turned off, the vehicle ECU 70 turns off the system main relay 28 and the relay 44 (the charging relay 42 is held off). ), The charging relay 42 is turned on, and a power transmission start request (a request to start charging the battery 26) is transmitted to the power transmission ECU 170 via the communication units 80 and 180. Then, when the power transmission ECU 170 receives the power transmission start request, the power transmission ECU 170 controls the high-frequency power circuit 140 so that power larger than the above-described weak power (power for charging the battery 26) is supplied to the power transmission coil 134. In the automobile 20, the power receiving coil 34 receives power from the power transmitting coil 134 in a contactless manner, and the AC power is converted into DC power by the charging circuit 40 and supplied to the battery 26. Thereby, the battery 26 is charged. When the storage ratio SOC of the battery 26 reaches a threshold value Sref (for example, 80%, 85%, 90%, etc.) at which charging ends, the vehicle ECU 70 sends a power transmission end request (battery 26 charging end request) to the communication unit. The power transmission ECU 170 transmitted to the power transmission ECU 170 via 80 and 180 receives the signal, and stops driving the high-frequency power circuit 140. Further, the vehicle ECU 70 turns off the charging relay 42. Thereby, charging of the battery 26 is completed.

  When an abnormality occurs in the power receiving unit 31 during charging of the battery 26 by such a sequence, the vehicle ECU 70 turns off the charging relay 42 after turning on the relay 44 and sends an emergency power transmission end request to the communication unit 80. , 180 to the power transmission ECU 170. And power transmission ECU170 which received this stops a high frequency power circuit 170 drive.

  Here, the reason why the charging relay 42 is turned off after the relay 44 is turned on when an abnormality occurs in the power receiving unit 31 while the battery 26 is being charged will be described. If the charging relay 42 is turned off without turning on the relay 44 while the battery 26 is being charged (power is being transmitted and received without contact between the power transmission coil 134 and the power receiving coil 34), the power reception seen from the power transmission unit 131 is performed. The impedance of the unit 31 fluctuates greatly, which may cause part of the power from the power transmission unit 131 (relatively large power) to be reflected by the power receiving unit 31 and return to the power transmission unit 131. On the other hand, when the relay 44 is turned on and then the charging relay 42 is turned off, a change in impedance of the power receiving unit 31 viewed from the power transmission unit 131 can be suppressed. The power reflected by the power receiving unit 31 can be reduced. As a result, the power factor of the power transmission unit 131 can be prevented from greatly deteriorating. Further, when the withstand voltage and withstand current of the power transmission unit 131 are determined and the power transmission unit 131 and thus the power transmission device 130 are designed, a margin for the reflected power can be set small.

  Further, as an abnormality of the power receiving unit 31, when the transmitted power Ptr of the power transmitting device 130 is equal to or higher than the first threshold Pref1 and the received power Pre of the power receiving device 30 is lower than the second threshold Pref2, which is smaller than the first threshold Pref1, the power receiving unit 31 For example, when the temperature Tre of the circuit 32 is equal to or higher than the threshold value Tref, the battery temperature Tb of the battery 26 is equal to or higher than the threshold value Tbref. The transmission power Ptr of the power transmission device 130 is calculated using the current Itr of the power transmission resonance circuit 132 detected by the current sensor 150 and the terminal voltage Vtr of the power transmission resonance circuit 132 detected by the voltage detection unit 152. Can do. The received power Pre of the power receiving device 30 is calculated using the current Ire of the power receiving resonance circuit 32 detected by the current sensor 50 and the terminal voltage Vre1 of the power receiving resonance circuit 32 detected by the voltage detection unit 52. Can do. A value detected by the temperature sensor 58 can be used as the temperature Tre of the power receiving resonance circuit 32. As the temperature Tb of the battery 26, a value detected by the temperature sensor 27c can be used. Instead of when the transmission power Ptr of the power transmission device 130 is equal to or higher than the first threshold Pref1 and the power reception power Pre of the power reception device 30 is less than the second threshold Pref2, the power transmission power Ptr of the power transmission device 130 and the power reception power of the power reception device 30 are replaced. A case where the power difference ΔP from Pre is equal to or larger than the threshold value ΔPref may be considered. Further, the input / output power Pb of the battery 26 may be used instead of the received power Pre of the power receiving device 30. The input / output power Pb of the battery 26 can be calculated using the battery voltage Vb detected by the voltage sensor 27a and the battery current Ib detected by the current sensor 27b.

  According to the power receiving device 30 mounted on the automobile 20 of the embodiment described above, the relay 44 of the power receiving unit 31 is turned off and the charging relay 42 is turned on to transmit power from the power transmitting unit 131 to the power receiving unit 31 in a contactless manner. When an abnormality occurs in the power receiving unit 31 while the battery 26 is being charged, the charging relay 42 is turned off after the relay 44 is turned on. Therefore, the impedance of the power receiving unit 31 viewed from the power transmission unit 131 is reduced. The change can be suppressed, and the reflected power by the power reception unit 31 with respect to the transmission power from the power transmission unit 131 can be reduced. As a result, the power factor of the power transmission unit 131 can be prevented from greatly deteriorating. Further, when the withstand voltage and withstand current of the power transmission unit 131 are determined and the power transmission unit 131 and thus the power transmission device 130 are designed, a margin for the reflected power can be set small.

  In the automobile 20 of the embodiment, the charging circuit 40 includes a rectifier circuit and a smoothing circuit. However, in addition to these, the charging circuit 40 may include a voltage conversion circuit that converts a voltage.

  In the automobile 20 of the embodiment, the power receiving unit 31 of the power receiving device 30 is arranged in the order of the power receiving resonance circuit 32, the relay 44 and the resistor 46, the charging relay 42, and the charging circuit 40 from the power receiving resonance circuit 32 side to the battery 26 side. 3, the power receiving unit 31B of the power receiving device 30B is connected from the power receiving resonance circuit 32 side to the battery 26 side, as illustrated in the modified example of the automobile 20B in FIG. The circuit 40B, the relay 44 and the resistor 46, the charging relay 42, and the DC / DC converter 41B may be arranged in this order. Here, the DC / DC converter 41B is controlled by the vehicle ECU 70. In the power receiving device 30B, the battery 26 side of the rectifier circuit 40B is in the DC power range, so that the voltage detecting units 54 and 56 (units having the rectifier circuit and the voltage sensor) provided in the power receiving device 30 of the embodiment are replaced. The voltage sensors 54B and 56B can be used without using a rectifier circuit. Thereby, the number of parts can be reduced.

  Although the automobile 20B according to this modification includes the DC / DC converter 41B, the automobile 20B may not include this. In the automobile 20B, the DC / DC converter 41B is provided on the battery 26 side of the charging relay 42. However, the DC / DC converter 41B may be provided between the rectifier circuit 40B and the charging relay 42. Good.

  In the automobiles 20 and 20B according to the embodiment and the modified example, the power receiving devices 30 and 30B include the voltage detection unit 56 and the voltage sensor 56B that detect the voltage Vre3 between the terminals of the resistor 46. A voltage detection unit or a voltage sensor that detects a voltage between the positive electrode side line and the negative electrode side line between the circuit 40B and the charging relay 42 may be used.

  In the embodiment, the vehicle 20 is an electric vehicle, but may be any vehicle provided with a battery or a power receiving device, and may be a hybrid vehicle, a fuel cell vehicle, or the like.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the power receiving unit 31 including the power receiving resonance circuit 32, the charging circuit 40, the charging relay 42, the relay 44, and the resistor 46 corresponds to the “power receiving unit”, and the vehicle ECU 70 corresponds to the “control unit”.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention can be used in the power receiving device manufacturing industry and the like.

  DESCRIPTION OF SYMBOLS 10 Non-contact power transmission / reception system, 20, 20B Car, 22 Motor, 24 Inverter, 26 Battery, 27a Voltage sensor, 27b Current sensor, 27c Temperature sensor, 28 System main relay, 30, 30B Power receiving device, 31, 31B Power receiving unit, 32 Receiving resonance circuit, 34 Receiving coil, 36 Capacitor, 40 Charging circuit, 40B Rectifier circuit, 41B DC / DC converter, 42 Charging relay, 44 Relay, 46 Resistance, 50 Current sensor, 52, 54, 56 Voltage detection Unit, 54B, 56B voltage sensor, 58 temperature sensor, 70 vehicle electronic control unit (vehicle ECU), 80 communication unit, 130 power transmission device, 131 power transmission unit, 132 power transmission resonance circuit, 134 power transmission coil, 136 capacitor, 140 High Frequency power supply circuit, 150 current sensor, 152 voltage detection unit, 170 electronic control unit for power transmission (power transmission ECU), 180 communication unit, 190 AC power source.

Claims (1)

A power receiving device comprising: a power receiving unit capable of receiving power from a power transmitting device in a non-contact manner and charging a battery; and a control means for controlling the power receiving unit,
The power receiving unit is:
A resonance circuit having a power reception coil for receiving power from a power transmission coil of the power transmission device in a contactless manner;
A charging circuit that converts AC power received by the resonance circuit into DC power and supplies the battery;
A first relay for connecting and releasing the connection between the battery and the resonant circuit;
A second relay and a resistor connected between the resonant circuit and the first relay and in parallel with the resonant circuit and in series with each other;
With
The control means turns off the second relay and turns on the first relay, and when an abnormality occurs in the power receiving unit during charging of the battery by power transmitted from the power transmission device to the power receiving unit. , After turning on the second relay, turning off the first relay,
A power receiving device.

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