Test method, power reception device, and non-contact power supply system

Abstract

This test method causes a DC voltage to be applied from a battery (84) to a rectification circuit (82) during a period in which a power reception device (80) is not receiving power and includes: a first abnormality determination using a detection voltage of a parallel switching element (SWp) after the parallel switching element (SWp) is turned on; and a second abnormality determination using a detection voltage of the parallel switching element (SWp) after the parallel switching element (SWp) is turned off.

Description

Inspection Method, Power Receiving Device, and Contactless Power Supply System Cross - Reference to Related Applications

[0001] This application is based on Japanese Application No. 2024 - 208874 filed on November 29, 2024, the contents of which are incorporated herein by reference.

[0002] This disclosure relates to an inspection method, a power receiving device, and a contactless power supply system.

[0003] Patent Document 1 discloses a device that short - circuits, for example, the first diode of a diode bridge for rectifying an alternating current by a switch in order to recirculate the received alternating current in a power receiving device for contactless power supply.

[0004] Special Table 2013 - 535948 Gazette

[0005] When a power receiving device includes a switch for circulating an alternating current as in the above - mentioned technology, this switch may fail. Note that this problem is not limited to the case where the rectifier circuit for rectifying the alternating current is a diode bridge, but is common in rectifier circuits with other circuit configurations as well.

[0006] This disclosure can be realized in the following forms.

[0007] In a first embodiment of this disclosure, a method for inspecting a power receiving device that receives power from a power transmitting device in a non-contact manner is provided. The power receiving device comprises a power receiving coil that is magnetically coupled to a power transmitting coil of the power transmitting device, a rectifier circuit that rectifies the AC power received by the power receiving coil and outputs DC power, and a battery to which the DC power is supplied. The rectifier circuit has a plurality of leg circuits and a first output terminal and a second output terminal that output the DC power, the second output terminal being a terminal set to a reference voltage, each of the plurality of leg circuits having a first semiconductor element electrically connected to the first output terminal and a second semiconductor element connected in series with the first semiconductor element, each of the first and second semiconductor elements being a diode or a switching element, one of the semiconductor elements being a diode, and the rectifier circuit being connected in parallel with the one semiconductor element. The inspection method comprises a parallel switching element and includes a first step of applying a DC voltage output from the battery to the rectifier circuit during a period when the power receiving device is not receiving power, and at least one of a second step and a third step performed after the first step, wherein in the second step, a first abnormality determination is made using at least one of the detection voltage of one semiconductor element and the detection voltage of the other semiconductor element among the first and second semiconductor elements after each of the parallel switching elements of the plurality of leg circuits is turned on, and in the third step, a second abnormality determination is made using at least one of the detection voltage of one semiconductor element and the detection voltage of the other semiconductor element after each of the plurality of leg circuits is turned off.

[0008] This configuration allows for testing whether or not a parallel switching element is faulty.

[0009] A second embodiment of the present disclosure provides a method for inspecting a power receiving device that receives power from a power transmitting device in a non-contact manner. The power receiving device comprises a power receiving coil that is magnetically coupled to a power transmitting coil of the power transmitting device, a rectifier circuit that rectifies the AC power received by the power receiving coil and outputs DC power, and a battery to which the DC power is supplied, wherein the rectifier circuit has a plurality of leg circuits and a first output terminal and a second output terminal that output the DC power, the second output terminal being a terminal set to a reference voltage, each of the plurality of leg circuits having a first semiconductor element electrically connected to the first output terminal and a second semiconductor element connected in series with the first semiconductor element, each of the first and second semiconductor elements being a diode or a switching element, and one of the semiconductor elements being the switching element. The inspection method includes a first step of applying a DC voltage output from the battery to the rectifier circuit during a period when the power receiving device is not receiving power, and at least one of a second step and a third step performed after the first step, wherein in the second step, a third abnormality determination is made using at least one of the detection voltage of one semiconductor element and the detection voltage of the other semiconductor element among the first and second semiconductor elements after each of the switching elements of the plurality of leg circuits is turned on, and in the third step, a fourth abnormality determination is made using at least one of the detection voltage of one semiconductor element and the detection voltage of the other semiconductor element after each of the switching elements of the plurality of leg circuits is turned off.

[0010] This configuration allows for testing whether or not a switching element is faulty.

[0011] In a third embodiment of the present disclosure, a power receiving device is provided that receives power from a power transmission device in a non-contact manner. The power receiving device comprises a power receiving coil that is magnetically coupled to a power transmission coil of the power transmission device, a rectifier circuit that rectifies the AC power received by the power receiving coil and outputs DC power, a battery to which the DC power is supplied, and a control device, wherein the rectifier circuit has a plurality of leg circuits and a first output terminal and a second output terminal that output the DC power, the second output terminal being a terminal set to a reference voltage, each of the plurality of leg circuits having a first semiconductor element electrically connected to the first output terminal and a second semiconductor element connected in series with the first semiconductor element, each of the first and second semiconductor elements being a diode or a switching element, and one of the semiconductor elements being a diode The rectifier circuit includes a parallel switching element connected in parallel to one of the semiconductor elements and a voltage sensor for detecting the voltage of the parallel switching element. The control device performs a first step of applying a DC voltage output from the battery to the rectifier circuit during a period when the power receiving device is not receiving power, and at least one of a second step and a third step performed after the first step. In the second step, a first abnormality determination is made using the detected voltage detected by the voltage sensor after each of the parallel switching elements of the plurality of leg circuits has been turned on. In the third step, a second abnormality determination is made using the detected voltage after each of the parallel switching elements of the plurality of leg circuits has been turned off.

[0012] This configuration allows for testing whether or not a parallel switching element is faulty.

[0013] In a fourth embodiment of the present disclosure, a contactless power supply system comprising a power transmission device and a power receiving device is provided. The power transmission device has a power transmission coil, the power receiving device comprises a power receiving coil magnetically coupled to the power transmission coil, a rectifier circuit that rectifies the AC power received by the power receiving coil and outputs DC power, a battery to which the DC power is supplied, and a control device, the rectifier circuit having a plurality of leg circuits, a first output terminal and a second output terminal that output the DC power, the second output terminal being a terminal set to a reference voltage, each of the plurality of leg circuits having a first semiconductor element electrically connected to the first output terminal and a second semiconductor element connected in series with the first semiconductor element, each of the first and second semiconductor elements being a diode or a switching element, and one of the semiconductor elements being a diode The rectifier circuit comprises a parallel switching element connected in parallel to one of the semiconductor elements and a voltage sensor for detecting the voltage of the parallel switching element. The control device performs a first step of applying a DC voltage output from the battery to the rectifier circuit during a period when the power receiving device is not receiving power, and at least one of a second step and a third step performed after the first step. In the second step, a first abnormality determination is made using the detected voltage detected by the voltage sensor after each of the parallel switching elements of the plurality of leg circuits has been turned on. In the third step, a second abnormality determination is made using the detected voltage after each of the parallel switching elements of the plurality of leg circuits has been turned off.

[0014] This configuration allows for testing whether or not a parallel switching element is faulty.

[0015] The above-mentioned and other purposes, features and advantages of this disclosure will be further clarified by the following detailed description with reference to the attached drawings. The drawings are as follows: Figure 1 is a schematic diagram showing the configuration of a contactless power supply system; Figure 2 is a circuit diagram of the contactless power supply system; Figure 3 is a flowchart showing the procedure of the inspection process; Figure 4 is a circuit diagram of a rectifier circuit of a second embodiment; Figure 5 is a circuit diagram of a rectifier circuit of a third embodiment; Figure 6 is a circuit diagram of a rectifier circuit of a fourth embodiment; and Figure 7 is a circuit diagram of a rectifier circuit of a fifth embodiment.

[0016] A. First Embodiment: A1. Schematic Configuration of the Contactless Power Supply System: As shown in Figure 1, the contactless power supply system 1 comprises a power transmission device 10 and a power receiving device 80. In this embodiment, the power transmission device 10 is buried under the road RS. The power receiving device 80 is mounted on a vehicle VE, which is a mobile body traveling on the road RS. While the vehicle VE is traveling, the power receiving device 80 is supplied with power from the power transmission device 10. Here, "while traveling" includes cases where the vehicle VE is moving and cases where the vehicle is stopped, such as at a traffic light. The vehicle VE is configured as, for example, an electric vehicle or a hybrid vehicle.

[0017] The power transmission device 10 includes a power transmission resonant circuit 12 having a power transmission coil L1, and an AC power supply 11 that supplies power to the power transmission resonant circuit 12. The AC power supply 11 supplies power to multiple power transmission resonant circuits 12. The multiple power transmission coils L1 are arranged along the direction of extension of the road RS.

[0018] Furthermore, the mobile device on which the power receiving device 80 is mounted is not limited to vehicles VE traveling on road RS, but may also be, for example, an AGV (Automated Guided Vehicle) or a mobile robot. Also, the power transmission device 10 may be installed not under the road RS, but on a sidewalk adjacent to the road RS, a parking lot, or along the route where the AGV travels.

[0019] The power receiving device 80 includes a battery 84, an auxiliary battery 94, a rectifier circuit 82, a power receiving resonant circuit 81 having a power receiving coil L2, a DC-DC converter 92, an inverter 91, a motor generator 93, an auxiliary device 95, a control device 96, and a vehicle speed sensor 97. In this embodiment, the power receiving coil L2 is located on the underside of the vehicle VE, opposite the power transmission coil L1.

[0020] A rectifier circuit 82 is connected to the power receiving resonant circuit 81. In the power receiving state, the rectifier circuit 82 converts the AC power received by the power receiving resonant circuit 81 into DC power, and supplies the converted DC power to the battery 84, the DC-DC converter 92, and the inverter 91.

[0021] The battery 84 is a secondary battery that is charged by the supplied DC power. The inverter 91 uses the supplied DC power to drive the motor generator 93. The motor generator 93 operates as a three-phase AC motor and generates the driving force for propulsion. In addition, the motor generator 93 operates as a generator when the vehicle VE is decelerated and regenerates power. The regenerated three-phase AC power is converted to DC power by the inverter 91 and used to charge the battery 84.

[0022] The DC-DC converter 92 steps down the DC power supplied from the rectifier circuit 82 and supplies the stepped-down DC power to the auxiliary battery 94 and the auxiliary equipment 95. The auxiliary equipment 95 includes the vehicle VE's air conditioning system, electric power steering system, headlights, turn signals, wipers and other peripheral equipment, and vehicle VE accessories. The auxiliary battery 94 is a secondary battery for powering the auxiliary equipment 95. The vehicle speed sensor 97 detects the vehicle VE's moving speed and outputs a signal indicating the detected moving speed to the control device 96.

[0023] The control device 96 controls various parts of the power receiving device 80, such as the inverter 91. The control device 96 is implemented including an ECU (engine control unit). The ECU may be implemented with a single microcontroller or with multiple microcontrollers. When multiple microcontrollers are included, for example, it may include a microcontroller that controls mechanisms related to the drive of the vehicle VE, such as the motor generator 93, and a microcontroller that controls mechanisms related to the battery 84, such as the rectifier circuit 82. Furthermore, the control device 96 may be implemented including an ECU that controls various parts and a higher-level ECU that controls multiple ECUs in a unified manner.

[0024] A microcontroller is configured as a computer, including a processor and memory. The processor executes programs stored in memory, thereby realizing each function.

[0025] A2. Circuit configuration of the contactless power supply system: As shown in Figure 2, the power transmission device 10 is equipped with a power transmission capacitor C1 in addition to the above configuration. The power transmission capacitor C1 is connected in series with the power transmission coil L1 to form a power transmission resonant circuit 12. Note that in Figure 2, only one of the multiple power transmission resonant circuits 12 connected to the AC power supply 11 is shown, and the other power transmission resonant circuits 12 are not shown.

[0026] The AC power supply 11 applies AC power at a predetermined operating frequency to the power transmission resonant circuit 12. In this embodiment, the operating frequency is 85 kHz. When the power transmission coil L1 and the power receiving coil L2 are magnetically coupled, the power transmission resonant circuit 12 enters a resonant state at the operating frequency.

[0027] In addition to the above configuration, the power receiving device 80 includes two power receiving capacitors C2, a filter 88, and an SMR (system main relay) 89 as a relay circuit. The power receiving coil L2 has one end L2a and the other end L2b. The two power receiving capacitors C2 are connected in series to each of the two ends L2a and L2b of the power receiving coil L2, respectively, to form a power receiving resonant circuit 81.

[0028] In this embodiment, the rectifier circuit 82 is implemented as a diode bridge. Specifically, the rectifier circuit 82 includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, and a smoothing capacitor C3. The rectifier circuit 82 has a first output terminal T1 and a second output terminal T2. The first output terminal T1 and the second output terminal T2 are terminals that output DC power. The first output terminal T1 is connected to the positive terminal of the battery 84. The second output terminal T2 is connected to the negative terminal of the battery 84 and is set to a reference voltage which is ground.

[0029] The rectifier circuit 82 has a plurality of leg circuits 98. The plurality of leg circuits 98 include a first leg circuit 98a and a second leg circuit 98b. The first leg circuit 98a has a first diode D1 and a third diode D3. The first diode D1 is a diode whose cathode is connected to the first output terminal T1. The third diode D3 is connected in series with the first diode D1. The cathode of the third diode D3 is connected in series with the anode of the first diode D1. The second leg circuit 98b has a second diode D2 and a fourth diode D4. The second diode D2 is a diode whose cathode is connected to the first output terminal T1. The fourth diode D4 is connected in series with the second diode D2. The cathode of the fourth diode D4 is connected in series with the anode of the second diode D2.

[0030] The transmission path through which the received AC current is transmitted, connected to one end L2a of the receiving coil L2, is called the first transmission path TLa. In this embodiment, the first transmission path TLa is the transmission path from one end L2a to the connection point between the first diode D1 and the third diode D3. The transmission path through which the received AC current is transmitted, connected to the other end L2b of the receiving coil L2, is called the second transmission path TLb. In this embodiment, the second transmission path TLb is the transmission path from the other end L2b to the connection point between the second diode D2 and the fourth diode D4.

[0031] The rectifier circuit 82 further includes two protection switches SWp and two voltage sensors 99. The two protection switches SWp are parallel switching elements connected in parallel to the third diode D3 and the fourth diode D4, respectively. One of the two protection switches SWp is connected in parallel to the third diode D3. The other of the two protection switches SWp is connected in parallel to the fourth diode D4. In this embodiment, the protection switches SWp are implemented using N-channel MOSFETs (metal-oxide-semiconductor field-effect transistors). Each voltage sensor 99 detects the voltage of the protection switch SWp and transmits a detection signal indicating the detected voltage Vde to the control device 96. Note that the protection switches SWp are connected in parallel to either the third diode D3 or the fourth diode D4. Therefore, the detected voltage Vde acquired by each voltage sensor 99 is also the voltage of the third diode D3 or the voltage of the fourth diode D4.

[0032] The control device 96 controls the two protection switches SWp using the first signal Sig1 input to the gate terminals of each of the two protection switches SWp.

[0033] Filter 88 suppresses the passage of noise components and allows signals in the desired frequency band to pass through. In Figure 2, filter 88 is shown as a second-order filter, but other filters such as low-pass filters or band-pass filters may also be used.

[0034] The SMR 89 electrically connects the rectifier circuit 82 and the battery 84 when it is ON, and disconnects the electrical connection between the rectifier circuit 82 and the battery 84 when it is OFF. The ON state of the SMR 89 refers to the state in which the contacts of the relay built into the SMR 89 are in contact. The OFF state of the SMR 89 refers to the state in which the contacts of the relay built into the SMR 89 are not in contact. Typically, when an abnormality occurs in the power receiving device 80, the control device 96 sets the SMR 89 to the OFF state, disconnecting the electrical connection between the rectifier circuit 82 and the SMR 89. In Figure 2, a circuit configuration with two relays is shown for the SMR 89, but the circuit configuration is not limited to this. The SMR 89 may have only one relay, or it may be configured with three or more relays.

[0035] The ON state of the SMR89 is also called the authorized state, which allows the supply of DC power to the battery 84. The OFF state of the SMR89 is also called the shut-off state, which cuts off the supply of DC power to the battery 84.

[0036] In the contactless power supply system 1, contactless power is supplied to the power receiving device 80 by magnetic field resonance between the power transmission coil L1 and the power receiving coil L2.

[0037] A3. Function of the protective switch: The protective switch SWp is a switch that has the function of electrically connecting the first transmission line TLa and the second transmission line TLb. By electrically connecting the first transmission line TLa and the second transmission line TLb, when an alternating current flows through the receiving coil L2, a current path CA is formed between one end L2a and the other end L2b of the receiving coil L2 through which the current flows.

[0038] In this embodiment, by setting the protective switch SWp to the ON state, the current path CA shown by the dashed arrow in Figure 2 is formed. The protective switch SWp is used to protect the circuit, for example, when an abnormality occurs in the power receiving device 80. Specifically, for example, if an abnormality occurs in which the voltage of the battery 84 is abnormally high, the SMR 89 is set to the OFF state. This cuts off the input current to the battery 84, thus protecting the battery 84. In this case, the protective switch SWp is further set to the ON state. This protects the circuit elements of the circuit preceding the battery 84. If current continues to flow to the circuit preceding the battery 84 while the SMR 89 is set to OFF, there is a risk that a voltage exceeding the rated voltage will be applied to the circuit elements of the circuit preceding the battery 84. In this regard, the circuit elements can be protected by forming the current path CA and creating a current loop.

[0039] In the above explanation, it was stated that the SMR89 is set to the off state when an abnormality occurs. However, the above explanation is only one example of operation in the event of an abnormality. The control device 96 does not only turn on the protection switch SWp when the SMR89 is set to the off state. Regardless of whether the SMR89 is in the off or on state, turning on the protection switch SWp protects the circuit preceding the battery 84.

[0040] For example, circuit elements such as protective switches SWp can experience failures such as short circuits. Therefore, the inspection method described below is used to inspect these circuit elements.

[0041] A4. Inspection Method: The control device 96 controls the power receiving device 80 by executing a control program that includes an inspection process program stored in memory. The inspection method for the power receiving device 80 is realized when the control device 96 executes the control program stored in memory. The control device 96 performs the inspection process during periods when the power receiving coil L2 is not receiving power. In this embodiment, the inspection process is performed during periods when there is no magnetic field radiation from the power transmitting device 10. This reduces the impact on the outside due to magnetic field radiation.

[0042] There are various methods for the control device 96 to determine that the power receiving coil L2 is not receiving power. For example, the control device 96 acquires the position information where the power transmission device 10 is arranged and the position information of the vehicle VE, and determines that the power receiving coil L2 is not receiving power when the position of the vehicle VE is outside the arrangement location of the power transmission device 10. Also, for example, when the non-contact power supply system 1 has a communication function between the power transmission device 10 and the power receiving device 80, the control device 96 can determine that the power receiving coil L2 is not receiving power through communication with the power transmission device 10 or the like.

[0043] In step S10 of FIG. 3, the control device 96 sets the SMR 89 to on. As a result, the DC voltage output from the battery 84 is applied to the rectifier circuit 82.

[0044] In step S12, the control device 96 sets the two protection switches SWp to the on state. In this embodiment, the waveforms of the two first signals Sig1 input to the two protection switches SWp are controlled to be the same as each other. In step S14, the control device 96 determines whether the detected voltage Vde of each of the two voltage sensors 99 is greater than a predetermined first reference voltage Vth1.

[0045] In the normal case where there is no failure in the circuit elements of the rectifier circuit 82, when the protection switch SWp is turned on, the detected voltage Vde becomes approximately zero volts. Therefore, when the detected voltage Vde is not about zero volts, it can be determined that the circuit elements of the rectifier circuit 82 are abnormal. The first reference voltage Vth1 is a voltage that enables the determination that it is abnormal when the detected voltage Vde is greater than the first reference voltage Vth1, and is obtained through experiments or the like and is stored in the memory in advance.

[0046] In step S14, specifically, when at least one of the two detection voltages Vde is greater than the first reference voltage Vth1, the control device 96 determines that the detection voltage Vde is greater than the first reference voltage Vth1. Also, for either of the two detection voltages Vde, when the detection voltage Vde is not greater than the first reference voltage Vth1, the control device 96 determines that the detection voltage Vde is not greater than the first reference voltage Vth1.

[0047] In step S14, when it is determined that the detection voltage Vde of the voltage sensor 99 is greater than the first reference voltage Vth1, in step S16, the control device 96 determines an abnormality and advances the processing step to step S18. Possible abnormalities in this case include an open failure of the protection switch SWp, a short-circuit failure of the first diode D1 or the second diode D2, etc.

[0048] In step S14, when it is determined that the detection voltage Vde of the voltage sensor 99 is not greater than the first reference voltage Vth1, the control device 96 determines normal and advances the processing step to step S18.

[0049] In step S18, the control device 96 sets the two protection switches SWp to the off state. In this embodiment, the waveforms of the two first signals Sig1 input to the two protection switches SWp are controlled to be the same as each other. In step S20, the control device 96 determines whether the detection voltage Vde of each of the two voltage sensors 99 is less than a predetermined third reference voltage Vth3.

[0050] When the circuit elements of the rectifier circuit 82 are normal, when the protection switch SWp is turned off, the detection voltage Vde generally becomes a voltage less than half of the battery voltage, which is the voltage of the battery 84. Therefore, when the detection voltage Vde is less than a voltage about half of the battery voltage, it can be determined that the circuit elements of the rectifier circuit 82 are abnormal. The third reference voltage Vth3 is a voltage that enables determination of an abnormality when the detection voltage Vde is less than the third reference voltage Vth3, and is obtained through experiments, etc., and is stored in the memory in advance.

[0051] In step S20, more specifically, the control device 96 determines that the detected voltage Vde is smaller than the third reference voltage Vth3 if at least one of the two detected voltages Vde is smaller than the third reference voltage Vth3. Furthermore, the control device 96 determines that the detected voltage Vde is not smaller than the third reference voltage Vth3 if neither of the two detected voltages Vde is smaller than the third reference voltage Vth3.

[0052] In step S20, if the control device 96 determines that the voltage Vde detected by the voltage sensor 99 is less than the third reference voltage Vth3, in step S22, it determines that there is an abnormality and terminates this processing routine. Possible abnormalities in this case include a short-circuit failure of the protection switch SWp, or a short-circuit failure of the third diode D3 or the fourth diode D4.

[0053] In step S20, if the control device 96 determines that the voltage Vde detected by the voltage sensor 99 is not less than the third reference voltage Vth3, it determines that the operation is normal and terminates this processing routine.

[0054] If the control device 96 determines that an abnormality has occurred in step S16, or if it determines that an abnormality has occurred in step S22, it prompts the user to repair the malfunction using, for example, an indicator light provided by a power receiving device 80 (not shown).

[0055] In this embodiment, the voltage sensor 99 is configured to detect the voltage of the protective switch SWp. In another embodiment, one of the two voltage sensors 99 may be configured to detect the voltage of the first diode D1. Similarly, the other voltage sensor 99 may be configured to detect the voltage of the second diode D2.

[0056] In this embodiment, in step S14, the control device 96 determines whether the detected voltage Vde of each of the two voltage sensors 99 is smaller than a predetermined second reference voltage Vth2. As described above, when the rectifier circuit 82 is functioning normally, when the protection switch SWp is turned on, the voltage of the protection switch SWp becomes approximately zero volts, and the voltages of the first diode D1 and the second diode D2 become approximately the battery voltage. Therefore, if the detected voltage Vde is not approximately the battery voltage, it can be determined that the circuit elements of the rectifier circuit 82 are abnormal. If, in step S14, the control device 96 determines that the detected voltage Vde is smaller than the second reference voltage Vth2, then in step S16, the control device 96 determines that there is an abnormality. The second reference voltage Vth2 is determined in advance by experimentation or the like and stored in the memory of the control device 96.

[0057] Furthermore, in this embodiment, in step S20, the control device 96 determines whether the detected voltage Vde of each of the two voltage sensors 99 is greater than a predetermined fourth reference voltage Vth4. As described above, when the rectifier circuit 82 is functioning normally, when the protection switch SWp is turned off, the voltage of the protection switch SWp, the voltage of the first diode D1, and the voltage of the second diode D2 will be about half the battery voltage. Therefore, if the detected voltage Vde is not about the battery voltage, it can be determined that the circuit elements of the rectifier circuit 82 are abnormal. If, in step S20, the control device 96 determines that the detected voltage Vde is greater than the fourth reference voltage Vth4, then in step S2, the control device 96 determines that there is an abnormality. The fourth reference voltage Vth4 is determined in advance by experimentation or the like and stored in the memory of the control device 96.

[0058] For example, in the first leg circuit 98a, the voltage sensor 99 may be provided on either the first diode D1 or the third diode D3. This allows for redundant testing.

[0059] The first diode D1 and the second diode D2 are also called the first semiconductor element. The third diode D3 and the fourth diode D4 are also called the second semiconductor element. Step S10 is also called the first step. Steps S12 to S16 are also called the second step. Steps S18 to S22 are also called the third step. Step S16 is also called the first abnormality determination or the third abnormality determination. Step S22 is also called the second abnormality determination or the fourth abnormality determination.

[0060] According to the first embodiment described above, the power receiving device 80 includes a power receiving coil L2, a rectifier circuit 82, a battery 84, and a control device 96. The rectifier circuit 82 includes a protection switch SWp connected in parallel to the third diode D3 and a protection switch SWp connected in parallel to the fourth diode D4. In step S14 of the inspection process, if the detected voltage Vde after the protection switch SWp is turned on is greater than the first reference voltage Vth1, it is determined to be abnormal. In step S22 of the inspection process, if the detected voltage Vde after the protection switch SWp is turned off is less than the third reference voltage Vth3, it is determined to be abnormal. In this way, by following this inspection method, a fault in the rectifier circuit 82 including the protection switch SWp can be detected. Furthermore, the inspection process is performed without flowing current through the power transmitting coil L1 or the power receiving coil L2. As a result, there is no radiation of a magnetic field to the outside, and the inspection can be performed regardless of the surrounding conditions, such as when people or equipment are around the vehicle VE.

[0061] B. Second Embodiment: As shown in Figure 4, the rectifier circuit 182 of the second embodiment differs from the rectifier circuit 82 of the first embodiment in that it includes a first resistive element R1 and a second resistive element R2. The inspection process in this embodiment is performed in the same manner as in the first embodiment. The same reference numerals are used for the same components and processing steps as in the first embodiment, and detailed explanations are omitted as appropriate.

[0062] As shown in Figure 4, the first resistor R1 is connected in parallel with the first diode D1. The second resistor R2 is connected in parallel with the second diode D2. Here, the combined resistance of the resistance of the first resistor R1 and the resistance of the first diode D1 when a reverse voltage is applied is called the first combined resistance. The combined resistance of the resistance of the third diode D3 when a reverse voltage is applied and the off resistance, which is the resistance when the protection switch SWp is off, is called the second combined resistance. The resistance of the first resistor R1 is set such that the first combined resistance is smaller than the second combined resistance.

[0063] Furthermore, the combined resistance value of the second resistive element R2 and the resistance value of the second diode D2 when a reverse voltage is applied is called the third combined resistance value. The combined resistance value of the fourth diode D4 when a reverse voltage is applied and the off resistance value, which is the resistance value when the protection switch SWp is off, is called the fourth combined resistance value. The resistance value of the second resistive element R2 is set such that the third combined resistance value is smaller than the fourth combined resistance value.

[0064] When the protection switch SWp is set to OFF, the second combined resistance value is set to be greater than the first combined resistance value. Therefore, if the circuit elements of the rectifier circuit 182 are functioning correctly, the detected voltage Vde will be greater than half the battery voltage. Consequently, for example, if the protection switch SWp short-circuits, the decrease in the detected voltage Vde from its normal state will be greater. Therefore, in step S20 of Figure 3, when determining whether there is an abnormality after turning off the protection switch SWp, misjudgments can be suppressed.

[0065] The second embodiment described above provides the same effects as the first embodiment. The rectifier circuit 182 also includes a first resistive element R1 and a second resistive element R2. The resistance values ​​of the first resistive element R1 and the second resistive element R2 are set to satisfy the above conditions. Therefore, erroneous judgments can be suppressed when determining whether or not there is an abnormality after the protection switch SWp is turned off.

[0066] C. Third Embodiment: As shown in Figure 5, the rectifier circuit 282 of this embodiment differs from the first embodiment in that the semiconductor element connected to the first output terminal T1 is a switching element. The same reference numerals are used for the same components and processing steps as in the first embodiment, and detailed explanations are omitted as appropriate.

[0067] As shown in Figure 5, the rectifier circuit 282 comprises a first switching element Q1, a second switching element Q2, a third diode D3, and a fourth diode D4. In this embodiment, the first switching element Q1 and the second switching element Q2 are N-channel MOSFETs. The drain of the first switching element Q1 is connected to the first output terminal T1. The drain of the second switching element Q2 is connected to the first output terminal T1. Control signals output from the control device 96 are input to the gates of the first switching element Q1 and the second switching element Q2, respectively.

[0068] The inspection process in this embodiment is performed in the same manner as in the first embodiment. The differences between the inspection process of the first embodiment and the inspection process of this embodiment will be explained using Figure 3. In step S12, the first switching element Q1 and the second switching element Q2 are set to the off state, and the protection switch SWp is set to the on state.

[0069] In step S18, the first switching element Q1 and the second switching element Q2 are set to the ON state, and the protection switch SWp is set to the OFF state. In this embodiment, when the first switching element Q1 and the second switching element Q2 are set to the ON state, the battery voltage is applied between the source and drain of the protection switch SWp when the protection switch SWp is functioning normally and is not faulty. If, for example, the protection switch SWp is short-circuited, the detected voltage Vde will be less than the voltage of the battery 84. In this way, by setting the first switching element Q1 and the second switching element Q2 to the ON state in step S18, the battery voltage can be applied to the protection switch SWp to be inspected. Since the difference between the detected voltage Vde in the normal state and the detected voltage Vde in the abnormal state becomes large, erroneous judgments in step S20 can be suppressed. In this embodiment, the third reference voltage Vth3 is set to a voltage slightly lower than the battery voltage.

[0070] The third embodiment described above provides the same effects as the first embodiment. The rectifier circuit 282 also includes a first switching element Q1 and a second switching element Q2. As a result, when the first switching element Q1 and the second switching element Q2 are set to the ON state, the battery voltage is applied to the protection switch SWp, thereby suppressing erroneous judgments in step S20.

[0071] D. Fourth Embodiment: As shown in Figure 6, the rectifier circuit 382 of this embodiment differs from the first embodiment in that it is composed of a semiconductor switching element instead of a diode. The same reference numerals are used for the same components and processing steps as in the first embodiment, and detailed explanations are omitted as appropriate.

[0072] The rectifier circuit 382 is configured as a synchronous rectifier circuit having a first switching element Q1, a second switching element Q2, a third switching element Q3, and a fourth switching element Q4. The first switching element Q1, the second switching element Q2, the third switching element Q3, and the fourth switching element Q4 constitute a bridge circuit. In this embodiment, the first switching element Q1, the second switching element Q2, the third switching element Q3, and the fourth switching element Q4 are realized as N-channel MOSFETs.

[0073] The control device 96 controls the rectifier circuit 382 using control signals input to the gate terminals of the first switching element Q1, the second switching element Q2, the third switching element Q3, and the fourth switching element Q4.

[0074] In rectification driving, the control device 96 drives the first switching element Q1 and the second switching element Q2 complementaryly to each other. Similarly, in rectification driving, the third switching element Q3 and the fourth switching element Q4 are driven complementaryly to each other. The first switching element Q1 and the fourth switching element Q4 are set to the ON state when an ON signal is input to them simultaneously, and set to the OFF state when an OFF signal is input to them simultaneously. Similarly, the second switching element Q2 and the third switching element Q3 are set to the ON state when an ON signal is input to them simultaneously, and set to the OFF state when an OFF signal is input to them simultaneously.

[0075] In this embodiment, the third switching element Q3 and the fourth switching element Q4 function as a protective switch SWp. In this embodiment, the first transmission path TLa is a transmission path from one end L2a to the connection point between the first switching element Q1 and the third switching element Q3. In this embodiment, the second transmission path TLb is a transmission path from the other end L2b to the connection point between the second switching element Q2 and the fourth switching element Q4.

[0076] The inspection process in this embodiment is performed in the same manner as in the first embodiment. The differences between the inspection process of the first embodiment and the inspection process of this embodiment will be explained using Figure 3. In step S12, the first switching element Q1 and the second switching element Q2 are set to the off state, and the third switching element Q3 and the fourth switching element Q4, which are protective switches SWp, are set to the on state.

[0077] In step S18, the first switching element Q1 and the second switching element Q2 are set to the ON state, while the third switching element Q3 and the fourth switching element Q4, which are the protection switch SWp, are set to the OFF state. Similar to the third embodiment described above, in step S18, when the first switching element Q1 and the second switching element Q2 are set to the ON state, the battery voltage is applied to the protection switch SWp, thereby suppressing the misjudgment in step S22.

[0078] The first switching element Q1 and the second switching element Q2 are also referred to as the first semiconductor element. The third switching element Q3 and the fourth switching element Q4 are also referred to as the second semiconductor element. The fourth embodiment described above provides the same effects as the first embodiment.

[0079] E. Fifth Embodiment: As shown in Figure 7, the rectifier circuit 482 of this embodiment differs from the first embodiment in that it comprises three leg circuits 98 corresponding to three power receiving coils L2 corresponding to three phases. The same reference numerals are used for the same components and processing steps as in the first embodiment, and detailed descriptions are omitted as appropriate. The three leg circuits 98 include a first leg circuit 98a, a second leg circuit 98b, and a third leg circuit 98c. The first leg circuit 98a includes diodes D11 and D14. The second leg circuit 98b includes diodes D12 and D15. The third leg circuit 98c includes diodes D13 and D16. A protective switch SWp is connected in parallel to each of the diodes D14, D15, and D16.

[0080] In this embodiment as well, by turning on the three protection switches SWp, the first transmission line TLa, the second transmission line TLb, and the third transmission line TLc are electrically connected to each other, thereby forming a current path CA. In this embodiment as well, inspection can be performed using the detection voltage Vde when the protection switch SWp is turned on, and inspection can be performed using the detection voltage Vde when the protection switch SWp is turned off. The fifth embodiment described above provides the same effects as the first embodiment.

[0081] F. Other Embodiments: (F1) In the first embodiment described above, after the inspection with the protection switch SWp ON in step S12, the inspection with the protection switch SWp OFF in step S16 is performed. In another embodiment, the inspection with the protection switch SWp OFF is performed first, followed by the inspection with the protection switch SWp ON in step S12. In yet another embodiment, only one of the inspection with the protection switch SWp ON or the inspection with the protection switch SWp OFF is performed.

[0082] (F2) In the first embodiment described above, in steps S14 and S18, the waveforms of the two first signals Sig1 input to the two protection switches SWp are controlled to be the same. In another embodiment, the waveforms of the two first signals Sig1 input to the two protection switches SWp may be controlled to be different from each other. For example, in step S12, the timing of turning on the two protection switches SWp can be staggered so that the two protection switches SWp can be tested one at a time.

[0083] (F3) In each of the above embodiments, the protection switch SWp is implemented with an N-channel MOSFET. In other embodiments, the protection switch SWp may be a P-channel MOSFET, or other transistors such as IGBTs, thyristors, or triacs. Also, in the first embodiment, the third switching element Q3 and the fourth switching element Q4 are the protection switch SWp, but the first switching element Q1 and the second switching element Q2 may also be the protection switch SWp.

[0084] (F4) In the first embodiment described above, the protective switch SWp is connected to the third diode D3 and the fourth diode D4, respectively. In another embodiment, the protective switch SWp may be connected to the first diode D1 and the second diode D2, respectively.

[0085] (F5) In the fourth embodiment described above, a first switching element Q1 and a second switching element Q2 are connected to the first output terminal T1. In another embodiment, a diode may be connected to the first output terminal T1 instead of the switching element.

[0086] (F6) In the first embodiment described above, a voltage sensor 99 is provided on both the third diode D3 and the fourth diode D4. In other embodiments, a voltage sensor 99 may be provided on either the third diode D3 or the fourth diode D4. Even if two voltage sensors 99 are not provided, it is still possible to inspect the protective switch SWp on which the voltage sensor 99 is provided. The same applies to the second to fourth embodiments.

[0087] (F7) In the first embodiment described above, the first reference voltage Vth1 and the third reference voltage Vth3 are pre-stored in the memory of the control device 96. The method for comparing the magnitude relationship between the voltage sensor 99 and the first reference voltage Vth1 or the third reference voltage Vth3 is not limited to the above embodiment. For example, a reference voltage generation circuit that generates the first reference voltage Vth1 and the third reference voltage Vth3 from the battery voltage may be provided, and the generated first reference voltage Vth1 or the third reference voltage Vth3 may be compared with the detected voltage Vde of the voltage sensor 99.

[0088] (F8) In the first embodiment described above, the power transmission resonant circuit 12 has a power transmission capacitor C1 connected in series with the power transmission coil L1, and the power receiving resonant circuit 81 has a power receiving capacitor C2 connected in series with the power receiving coil L2, which is a so-called S-S circuit configuration. The circuit configuration of the power transmission resonant circuit 12 and the circuit configuration of the power receiving resonant circuit 81 are not limited to the S-S method. (a) For example, the power transmission resonant circuit 12 may have a power transmission capacitor C1 connected in parallel with the power transmission coil L1, and the power receiving resonant circuit 81 may have a power receiving capacitor C2 connected in series with the power receiving coil L2, which is a so-called P-S circuit configuration. (b) In addition to the power transmission capacitor C1 connected in series with the power transmission coil L1, the power receiving resonant circuit 81 may also have a capacitor connected in parallel with the power transmission coil L1, and each of the two power receiving capacitors C2 is connected in series with each of the ends of the power receiving coil L2, which is a so-called P-SS circuit configuration. (c) The power transmission resonant circuit 12 may also include a closed circuit in which a coil and a capacitor are connected in series. The coil in this closed circuit is positioned so as to be magnetically coupled with the receiving coil L2 when the power transmission coil L1 and the receiving coil L2 are magnetically coupled. (d) Furthermore, the capacitor in the closed circuit may be connected in parallel with the coil instead of in series. (e) The power transmission resonant circuit 12 may also include a coil connected in series with the power transmission coil L1, as well as a capacitor connected in parallel with the coil. This coil is positioned so as to be magnetically coupled with the receiving coil L2 when the power transmission coil L1 and the receiving coil L2 are magnetically coupled.

[0089] The control devices and methods described herein may be implemented by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. Alternatively, the control devices and methods described herein may be implemented by a dedicated computer provided by configuring a processor by one or more dedicated hardware logic circuits. Alternatively, the control devices and methods described herein may be implemented by one or more dedicated computers configured by a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by the computer on a computer-readable non-transitional tangible recording medium.

[0090] This disclosure is not limited to the embodiments and modifications described above, and can be implemented in various configurations without departing from its spirit. For example, the technical features in the embodiments and modifications corresponding to the technical features in each form described in the summary of the invention can be replaced or combined as appropriate in order to solve some or all of the above-mentioned problems, or to achieve some or all of the above-mentioned effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate.

[0091] Other forms: The features of this disclosure are as follows. (Form 1) A method for inspecting a power receiving device (80) that receives power from a power transmitting device (10) in a non-contact manner, wherein the power receiving device comprises: a power receiving coil (L2) that is magnetically coupled to a power transmitting coil (L1) provided by the power transmitting device; a rectifier circuit (82, 182, 282) that rectifies the AC power received by the power receiving coil and outputs DC power; and a battery (84) to which the DC power is supplied, wherein the rectifier circuit has a plurality of leg circuits (98), a first output terminal (T1) and a second output terminal (T2) that output the DC power, the second output terminal being a terminal set to a reference voltage, each of the plurality of leg circuits having a first semiconductor element (D1, D2, Q1, Q2) electrically connected to the first output terminal, and a second semiconductor element (D3, D4) connected in series with the first semiconductor element, and each of the first and second semiconductor elements being a diode or a switching element. The inspection method comprises: a first semiconductor element and a second semiconductor element, where one of the semiconductor elements is a diode; the rectifier circuit includes a parallel switching element (SWp) connected in parallel to the first semiconductor element; and a first step of applying a DC voltage output from the battery to the rectifier circuit during a period when the power receiving device is not receiving power; and at least one of a second step and a third step performed after the first step, wherein in the second step, a first abnormality determination is made using at least one of the detection voltage of the first semiconductor element and the detection voltage of the other semiconductor element of the first and second semiconductor elements after each of the parallel switching elements of the plurality of leg circuits is turned on; and in the third step, a second abnormality determination is made using at least one of the detection voltage of the first semiconductor element and the detection voltage of the other semiconductor element after each of the parallel switching elements of the plurality of leg circuits is turned off.(Form 2) A method for inspecting a power receiving device (80) that receives power from a power transmitting device (10) in a non-contact manner, wherein the power receiving device comprises: a power receiving coil (L2) that is magnetically coupled to a power transmitting coil (L1) provided by the power transmitting device; a rectifier circuit (382) that rectifies the AC power received by the power receiving coil and outputs DC power; and a battery (84) to which the DC power is supplied, wherein the rectifier circuit has a plurality of leg circuits (98), a first output terminal (T1) and a second output terminal (T2) that output the DC power, the second output terminal being a terminal set to a reference voltage, each of the plurality of leg circuits having a first semiconductor element (Q1, Q2) electrically connected to the first output terminal, and a second semiconductor element (Q3, Q4) connected in series with the first semiconductor element, and each of the first semiconductor element and the second semiconductor element being a diode or a switching element. The inspection method comprises: a first step of applying a DC voltage output from the battery to the rectifier circuit during a period when the power receiving device is not receiving power; and at least one of a second step performed after the first step and a third step performed after the first step, wherein in the second step, a third abnormality determination is made using at least one of the detection voltage of the one semiconductor element and the detection voltage of the other semiconductor element of the first semiconductor element and the second semiconductor element after each of the plurality of leg circuits has been turned on; and in the third step, a fourth abnormality determination is made using at least one of the detection voltage of the one semiconductor element and the detection voltage of the other semiconductor element after each of the plurality of leg circuits has been turned off. (Embodiment 3) An inspection method according to Embodiment 1, wherein in the first abnormality determination, an abnormality is determined if the detection voltage of one semiconductor element is greater than a predetermined first reference voltage, and an abnormality is determined if the detection voltage of the other semiconductor element is less than a predetermined second reference voltage.(Form 4) An inspection method according to Form 2, wherein in the third abnormality determination, an abnormality is determined if the detection voltage of one semiconductor element is greater than a predetermined first reference voltage, and an abnormality is determined if the detection voltage of the other semiconductor element is less than a predetermined second reference voltage. (Form 5) An inspection method according to Form 1 or 3, wherein in the second abnormality determination, an abnormality is determined if the detection voltage of one semiconductor element is less than a predetermined third reference voltage, and an abnormality is determined if the detection voltage of the other semiconductor element is greater than a predetermined fourth reference voltage. (Form 6) An inspection method according to Form 2 or 4, wherein in the fourth abnormality determination, an abnormality is determined if the detection voltage of one semiconductor element is less than a predetermined third reference voltage, and an abnormality is determined if the detection voltage of the other semiconductor element is greater than a predetermined fourth reference voltage. (Embodiment 7) An inspection method according to Embodiment 1, 3, or 5, wherein the other semiconductor element is a diode, the rectifier circuit further comprises resistive elements (R1, R2) connected in parallel to the other semiconductor element, and the resistance value of the resistive element is set such that the combined resistance value of the resistance value of the other semiconductor element when a reverse voltage is applied and the resistance value of the resistive element is smaller than the combined resistance value of the resistance value of the one semiconductor element when a reverse voltage is applied and the off-resistance value of the parallel switching element. (Embodiment 8) An inspection method according to Embodiment 1, 3, or 5, wherein the other semiconductor element is the switching element. (Embodiment 9) An inspection method according to any one of embodiments 1 to 8, wherein the power receiving device further comprises a relay circuit (89) connected between the rectifier circuit and the battery, which can be switched between an authorized state that permits the supply of the DC power to the battery and an interrupted state that interrupts the supply of the DC power to the battery, wherein in the first step, the relay circuit is set to the authorized state, and the first step and at least one of the second step and the third step are performed during a period when there is no magnetic field radiation from the power transmitting device.(Form 10) A power receiving device (80) that receives power from a power transmitting device (10) in a non-contact manner, comprising: a power receiving coil (L2) that is magnetically coupled to a power transmitting coil (L1) provided by the power transmitting device; a rectifier circuit (82, 182, 282) that rectifies the AC power received by the power receiving coil and outputs DC power; a battery (84) to which the DC power is supplied; and a control device (96), wherein the rectifier circuit has a plurality of leg circuits (98), a first output terminal (T1) and a second output terminal (T2) that output the DC power, the second output terminal being a terminal set to a reference voltage, and each of the plurality of leg circuits has a first semiconductor element (D1, D2, Q1, Q2) electrically connected to the first output terminal, and a second semiconductor element (D3, D4) connected in series with the first semiconductor element. Each of the first semiconductor element and the second semiconductor element is a diode or a switching element, and one of the semiconductor elements is a diode, the rectifier circuit comprises a parallel switching element (SWp) connected in parallel to the one semiconductor element and a voltage sensor (99) for detecting the voltage of the parallel switching element, the control device performs a first step of applying a DC voltage output from the battery to the rectifier circuit during a period when the power receiving device is not receiving power, at least one of a second step performed after the first step and a third step performed after the first step, in the second step a first abnormality determination is made using the detected voltage detected by the voltage sensor after each of the parallel switching elements of the plurality of leg circuits is turned on, and in the third step a second abnormality determination is made using the detected voltage after each of the parallel switching elements of the plurality of leg circuits is turned off, the power receiving device.(Embodiment 11) A power receiving device according to Embodiment 10, wherein the other semiconductor element of the first semiconductor element and the second semiconductor element is a diode, the rectifier circuit further comprises resistive elements (R1, R2) connected in parallel to the other semiconductor element, and the resistance value of the resistive element is set such that the combined resistance value of the resistance value of the other semiconductor element when a reverse voltage is applied and the resistance value of the resistive element is smaller than the combined resistance value of the resistance value of the first semiconductor element when a reverse voltage is applied and the off-resistance value of the parallel switching element.(Embodiment 12) A contactless power supply system (1) comprising a power transmission device (10) and a power receiving device (80), wherein the power transmission device has a power transmission coil (L1), the power receiving device comprises a power receiving coil (L2) that is magnetically coupled to the power transmission coil, a rectifier circuit (82, 182, 282) that rectifies the AC power received by the power receiving coil and outputs DC power, a battery (84) to which the DC power is supplied, and a control device (96), wherein the rectifier circuit has a plurality of leg circuits (98), a first output terminal (T1) and a second output terminal (T2) that output the DC power, the second output terminal is a terminal set to a reference voltage, and each of the plurality of leg circuits has a first semiconductor element (D1, D2, Q1, Q2) electrically connected to the first output terminal and a second semiconductor element (D3, D4) connected in series with the first semiconductor element. Each of the first semiconductor element and the second semiconductor element is a diode or a switching element, and one of the semiconductor elements is a diode, the rectifier circuit comprises a parallel switching element (SWp) connected in parallel to the one semiconductor element and a voltage sensor (99) for detecting the voltage of the parallel switching element, the control device performs a first step of applying a DC voltage output from the battery to the rectifier circuit during a period when the power receiving device is not receiving power, a second step performed after the first step and a third step performed after the first step, in the second step, a first abnormality determination is made using the detected voltage detected by the voltage sensor after each of the parallel switching elements of the plurality of leg circuits is turned on, and in the third step, a second abnormality determination is made using the detected voltage after each of the parallel switching elements of the plurality of leg circuits is turned off, a contactless power supply system.

Claims

1. A method for inspecting a power receiving device (80) that receives power from a power transmitting device (10) in a non-contact manner, wherein the power receiving device comprises: a power receiving coil (L2) that is magnetically coupled to a power transmitting coil (L1) provided by the power transmitting device; a rectifier circuit (82, 182, 282) that rectifies the AC power received by the power receiving coil and outputs DC power; and a battery (84) to which the DC power is supplied, wherein the rectifier circuit has a plurality of leg circuits (98), a first output terminal (T1) and a second output terminal (T2) that output the DC power, the second output terminal being a terminal set to a reference voltage, each of the plurality of leg circuits having a first semiconductor element (D1, D2, Q1, Q2) electrically connected to the first output terminal, and a second semiconductor element (D3, D4) connected in series with the first semiconductor element, and each of the first and second semiconductor elements being a diode or a switching element. The inspection method comprises: a first semiconductor element and a second semiconductor element, where one of the semiconductor elements is a diode; the rectifier circuit includes a parallel switching element (SWp) connected in parallel to the first semiconductor element; and a first step of applying a DC voltage output from the battery to the rectifier circuit during a period when the power receiving device is not receiving power; and at least one of a second step and a third step performed after the first step, wherein in the second step, a first abnormality determination is made using at least one of the detection voltage of the first semiconductor element and the detection voltage of the other semiconductor element of the first and second semiconductor elements after each of the parallel switching elements of the plurality of leg circuits is turned on; and in the third step, a second abnormality determination is made using at least one of the detection voltage of the first semiconductor element and the detection voltage of the other semiconductor element after each of the parallel switching elements of the plurality of leg circuits is turned off.

2. A method for inspecting a power receiving device (80) that receives power from a power transmitting device (10) in a non-contact manner, wherein the power receiving device comprises: a power receiving coil (L2) that is magnetically coupled to a power transmitting coil (L1) provided by the power transmitting device; a rectifier circuit (382) that rectifies the AC power received by the power receiving coil and outputs DC power; and a battery (84) to which the DC power is supplied, wherein the rectifier circuit has a plurality of leg circuits (98), a first output terminal (T1) and a second output terminal (T2) that output the DC power, the second output terminal being a terminal set to a reference voltage, each of the plurality of leg circuits having a first semiconductor element (Q1, Q2) electrically connected to the first output terminal, and a second semiconductor element (Q3, Q4) connected in series with the first semiconductor element, and each of the first and second semiconductor elements being a diode or a switching element. The inspection method comprises: a first step of applying a DC voltage output from the battery to the rectifier circuit during a period when the power receiving device is not receiving power; and at least one of a second step performed after the first step and a third step performed after the first step, wherein in the second step, a third abnormality determination is made using at least one of the detection voltage of the one semiconductor element and the detection voltage of the other semiconductor element of the first semiconductor element and the second semiconductor element after each of the plurality of leg circuits has been turned on; and in the third step, a fourth abnormality determination is made using at least one of the detection voltage of the one semiconductor element and the detection voltage of the other semiconductor element after each of the plurality of leg circuits has been turned off.

3. An inspection method according to claim 1, wherein, in the first abnormality determination, an abnormality is determined when the detection voltage of one semiconductor element is greater than a predetermined first reference voltage, and an abnormality is determined when the detection voltage of the other semiconductor element is less than a predetermined second reference voltage.

4. An inspection method according to claim 2, wherein in the third abnormality determination, an abnormality is determined when the detection voltage of one semiconductor element is greater than a predetermined first reference voltage, and an abnormality is determined when the detection voltage of the other semiconductor element is less than a predetermined second reference voltage.

5. An inspection method according to claim 1, wherein in the second abnormality determination, an abnormality is determined when the detection voltage of one semiconductor element is less than a predetermined third reference voltage, and an abnormality is determined when the detection voltage of the other semiconductor element is greater than a predetermined fourth reference voltage.

6. An inspection method according to claim 2, wherein in the fourth abnormality determination, an abnormality is determined when the detection voltage of one semiconductor element is less than a predetermined third reference voltage, and an abnormality is determined when the detection voltage of the other semiconductor element is greater than a predetermined fourth reference voltage.

7. An inspection method according to claim 1, wherein the other semiconductor element is a diode, the rectifier circuit further comprises resistive elements (R1, R2) connected in parallel to the other semiconductor element, and the resistance values ​​of the resistive elements are set such that the combined resistance value of the resistance value of the other semiconductor element when a reverse voltage is applied and the resistance value of the resistive elements is smaller than the combined resistance value of the resistance value of the one semiconductor element when a reverse voltage is applied and the off-resistance value of the parallel switching element.

8. The inspection method according to claim 1, wherein the other semiconductor element is the switching element.

9. The inspection method according to claim 1, wherein the power receiving device further comprises a relay circuit (89) connected between the rectifier circuit and the battery, which can be switched between an authorized state that permits the supply of the DC power to the battery and an interrupted state that interrupts the supply of the DC power to the battery, wherein in the first step, the relay circuit is set to the authorized state, and the first step and at least one of the second step and the third step are performed during a period when there is no magnetic field radiation from the power transmitting device.

10. A power receiving device (80) that receives power from a power transmitting device (10) in a non-contact manner, comprising: a power receiving coil (L2) that is magnetically coupled to a power transmitting coil (L1) provided by the power transmitting device; a rectifier circuit (82, 182, 282) that rectifies the AC power received by the power receiving coil and outputs DC power; a battery (84) to which the DC power is supplied; and a control device (96), wherein the rectifier circuit has a plurality of leg circuits (98), a first output terminal (T1) and a second output terminal (T2) that output the DC power, the second output terminal being a terminal set to a reference voltage, each of the plurality of leg circuits having a first semiconductor element (D1, D2, Q1, Q2) electrically connected to the first output terminal, and a second semiconductor element (D3, D4) connected in series with the first semiconductor element, each of the first and second semiconductor elements being a diode or a switching element. A power receiving device wherein one of the first semiconductor element and the second semiconductor element is a diode, the rectifier circuit comprises a parallel switching element (SWp) connected in parallel to the one semiconductor element and a voltage sensor (99) for detecting the voltage of the parallel switching element, the control device performs a first step of applying a DC voltage output from the battery to the rectifier circuit during a period when the power receiving device is not receiving power, and at least one of a second step and a third step performed after the first step, the second step of performing a first abnormality determination using the detected voltage detected by the voltage sensor after turning on each of the parallel switching elements of the plurality of leg circuits, and the third step of performing a second abnormality determination using the detected voltage after turning off each of the parallel switching elements of the plurality of leg circuits.

11. A power receiving device according to claim 10, wherein the other semiconductor element among the first semiconductor element and the second semiconductor element is a diode, the rectifier circuit further comprises resistive elements (R1, R2) connected in parallel to the other semiconductor element, and the resistance value of the resistive element is set such that the combined resistance value of the resistance value of the other semiconductor element when a reverse voltage is applied and the resistance value of the resistive element is smaller than the combined resistance value of the resistance value of the first semiconductor element when a reverse voltage is applied and the off-resistance value of the parallel switching element.

12. A contactless power supply system (1) comprising a power transmission device (10) and a power receiving device (80), wherein the power transmission device has a power transmission coil (L1), the power receiving device comprises a power receiving coil (L2) that is magnetically coupled to the power transmission coil, a rectifier circuit (82, 182, 282) that rectifies the AC power received by the power receiving coil and outputs DC power, a battery (84) to which the DC power is supplied, and a control device (96), wherein the rectifier circuit has a plurality of leg circuits (98), a first output terminal (T1) and a second output terminal (T2) that output the DC power, the second output terminal is a terminal set to a reference voltage, and each of the plurality of leg circuits has a first semiconductor element (D1, D2, Q1, Q2) electrically connected to the first output terminal and a second semiconductor element (D3, D4) connected in series with the first semiconductor element. Each of the first semiconductor element and the second semiconductor element is a diode or a switching element, and one of the semiconductor elements is a diode, the rectifier circuit comprises a parallel switching element (SWp) connected in parallel to the one semiconductor element and a voltage sensor (99) for detecting the voltage of the parallel switching element, the control device performs a first step of applying a DC voltage output from the battery to the rectifier circuit during a period when the power receiving device is not receiving power, a second step performed after the first step and a third step performed after the first step, in the second step, a first abnormality determination is made using the detected voltage detected by the voltage sensor after each of the parallel switching elements of the plurality of leg circuits is turned on, and in the third step, a second abnormality determination is made using the detected voltage after each of the parallel switching elements of the plurality of leg circuits is turned off, a contactless power supply system.

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