Non-contact power supply system, power reception device, and power transmission device

Abstract

To provide a non-contact power supply system capable of starting power at an early stage.SOLUTION: A non-contact power supply system 1 supplies power in a non-contact manner to a power reception device 80 from a power transmission device 10. The power reception device includes: a secondary side resonance circuit 81; a magnetic flux generation coil L2 for generating a magnetic flux discharged to a primary side coil L1; a magnetic flux generation circuit 86 that includes a pulse generation circuit 82 that supplies power to the magnetic flux generation coil, and a secondary side control circuit 85 that controls the pulse generation circuit; and a secondary side detection circuit M2 that detects at least any one of a voltage value supplied to the pulse generation circuit, a current value flowing through the secondary side coil, and a magnitude of the magnetic flux generated from the primary side coil. The power transmission device is shifted from a standby mode to a power transmission mode where a power transmission current is passed to the primary side coil in the case where an increase in magnetic flux linked to the primary side coil is detected by the primary side detection circuit, and the magnetic flux generation circuit adjusts the magnetic flux to be generated by using a detection value of the secondary side detection circuit.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a contactless power supply device, a power receiving device, and a power transmitting device. [Background technology]

[0002] Various technologies have been proposed for contactlessly supplying power from the power transmitting side to the power receiving side by electromagnetic induction (for example, Patent Document 1). In the technology of Patent Document 1, a charging device on the power transmitting side receives the measurement results of the electromagnetic field strength transmitted from a device on the power receiving side using two-way wireless communication, and the charging device moves to an optimal position and starts transmitting power. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-88178 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, if it takes time to communicate via two-way wireless communication before the start of power transmission, the start of power transmission may be delayed. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] According to a first embodiment of the present disclosure, there is provided a contactless power feeding system (1, 201, 301) that wirelessly feeds power from a power transmitting device (10, 210, 310) to a power receiving device (80, 280, 380). The power transmitting device includes a primary side resonant circuit (12) having a primary side coil (L1) and a primary side capacitor (C1), an AC power source (11) that applies AC power of a predetermined operating frequency to the primary side resonant circuit, and a primary side detection circuit (120) for detecting the magnitude of a magnetic flux interlinked with the primary side coil or the magnitude of a magnetic flux in the vicinity of the primary side coil. The power receiving device includes a secondary side resonant circuit (81) having a secondary side coil (L2) and a secondary side capacitor (C2) for magnetically coupling with the primary side coil, a magnetic flux generating coil (L2) for generating a magnetic flux to be radiated to the primary side coil in a standby state of the power transmitting device, and a pulse generating circuit (82) for supplying AC power to the magnetic flux generating coil. a secondary side detection circuit (M2, 281, M3) that detects at least one of a voltage value supplied to the pulse generating circuit, a current value flowing in the secondary coil or the pulse generating circuit, and a magnitude of magnetic flux generated from the primary side coil, and when an increase in magnetic flux linking with the primary side coil or magnetic flux in the vicinity of the primary side coil is detected by the primary side detection circuit, the power transmitting device transitions from the standby state to a power transmitting state in which a transmission current is passed through the primary side coil, and the magnetic flux generating circuit adjusts the generated magnetic flux using the detection value of the secondary side detection circuit.

[0007] According to this embodiment, the power transmitting device transitions from a standby state to a power transmitting state by detecting an increase in the magnetic flux linking the primary coil by the magnetic flux generating circuit or the magnetic flux near the primary coil by the primary detection circuit. Therefore, the contactless power supply system can start contactless power supply early. In addition, the magnetic flux generating circuit can appropriately control the magnitude of the magnetic flux generated by the magnetic flux generating coil by adjusting the generated magnetic flux using the detection value of the secondary detection circuit.

[0008] According to a second embodiment of the present disclosure, there is provided a power receiving device (80, 280, 380) that receives power contactlessly from a power transmitting device (10, 210, 310). The power transmitting device includes a primary resonant circuit (12) having a primary coil (L1) and a primary capacitor (C1), an AC power source (11) that applies AC power of a predetermined operating frequency to the primary resonant circuit, and a primary detection circuit (120) for detecting the magnitude of a magnetic flux interlinked with the primary coil or the magnitude of a magnetic flux in the vicinity of the primary coil. The power receiving device includes a secondary resonant circuit (81) having a secondary coil (L2) and a secondary capacitor (C2) for magnetically coupling with the primary coil, a magnetic flux generating coil (L2) for generating a magnetic flux to be radiated to the primary coil in a standby state of the power transmitting device, and a pulse generating circuit (82) for supplying AC power to the magnetic flux generating coil. a secondary side detection circuit (M2, 281, M3) that detects at least one of a voltage value supplied to the pulse generating circuit, a current value flowing in the secondary coil or the pulse generating circuit, and a magnitude of magnetic flux generated from the primary side coil, and when an increase in magnetic flux linking with the primary side coil or magnetic flux in the vicinity of the primary side coil is detected by the primary side detection circuit, the power transmitting device transitions from the standby state to a power transmitting state in which a transmission current is passed through the primary side coil, and the magnetic flux generating circuit adjusts the generated magnetic flux using the detection value of the secondary side detection circuit.

[0009] According to this embodiment, the power transmitting device transitions from a standby state to a power transmitting state by detecting an increase in the magnetic flux linking the primary coil by the magnetic flux generating circuit or the magnetic flux near the primary coil by the primary detection circuit. Therefore, the contactless power supply system can start contactless power supply early. In addition, the magnetic flux generating circuit can appropriately control the magnitude of the magnetic flux generated by the magnetic flux generating coil by adjusting the generated magnetic flux using the detection value of the secondary detection circuit.

[0010] According to a third embodiment of the present disclosure, there is provided a power transmitting device (10, 210, 310) that wirelessly supplies power to a power receiving device (80, 280, 380). The power transmitting device includes a primary resonant circuit (12) having a primary coil (L1) and a primary capacitor (C1), an AC power source (11) that applies AC power of a predetermined operating frequency to the primary resonant circuit, and a primary detection circuit (120) for detecting the magnitude of a magnetic flux interlinked with the primary coil or the magnitude of a magnetic flux in the vicinity of the primary coil. The power receiving device includes a secondary resonant circuit (81) having a secondary coil (L2) and a secondary capacitor (C2) for magnetically coupling with the primary coil, a magnetic flux generating coil (L2) for generating a magnetic flux to be radiated to the primary coil in a standby state of the power transmitting device, and a pulse generating circuit (82) for supplying AC power to the magnetic flux generating coil. a secondary side detection circuit (M2, 281, M3) that detects at least one of a voltage value supplied to the pulse generating circuit, a current value flowing in the secondary coil or the pulse generating circuit, and a magnitude of magnetic flux generated from the primary side coil, wherein the magnetic flux generating circuit adjusts the generated magnetic flux using the detection value of the secondary side detection circuit, and when the primary side detection circuit detects an increase in magnetic flux linking with the primary side coil or in the vicinity of the primary side coil, the power transmitting device transitions from the standby state to a power transmitting state in which a transmission current flows to the primary side coil.

[0011] According to this embodiment, the power transmitting device transitions from a standby state to a power transmitting state by detecting an increase in the magnetic flux linking the primary coil by the magnetic flux generating circuit or the magnetic flux near the primary coil by the primary detection circuit. Therefore, the contactless power supply system can start contactless power supply early. In addition, the magnetic flux generating circuit can appropriately control the magnitude of the magnetic flux generated by the magnetic flux generating coil by adjusting the generated magnetic flux using the detection value of the secondary detection circuit. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram of a contactless power supply system. [Diagram 2] FIG. 1 is a circuit diagram of a contactless power supply system according to a first embodiment. [Diagram 3] 6 is a diagram showing a change over time in the positional relationship between a primary coil and a secondary coil. [Figure 4] FIG. 4 is a diagram showing a power supply start sequence according to the first embodiment. [Diagram 5] FIG. 4 is a diagram showing the waveform of a control signal. [Figure 6] FIG. 4 is a diagram showing the relationship between the drive frequency and the current flowing through a secondary coil. [Figure 7] FIG. 4 is a diagram showing the relationship between waiting time and each period of burst driving. [Figure 8] FIG. 4 is a diagram showing the relationship between vehicle speed and burst period. [Figure 9] FIG. 11 is a circuit diagram of a non-contact power supply system according to a second embodiment. [Figure 10] FIG. 11 is a diagram showing a power supply start sequence according to the second embodiment. [Figure 11] FIG. 4 is a diagram for explaining control of a pulse generating circuit. [Figure 12] 1A and 1B are diagrams for explaining an equivalent circuit and a method for calculating a coupling coefficient. [Figure 13] FIG. 11 is a circuit diagram of a contactless power supply system according to a third embodiment. [Figure 14] FIG. 11 is a diagram showing a power supply start sequence according to the third embodiment. [Figure 15] 13 is a first flowchart showing an abnormality detection process according to the fourth embodiment. [Figure 16] 20 is a second flowchart showing the abnormality detection process according to the fourth embodiment. [Figure 17] FIG. 13 is a circuit diagram of a power receiving device according to a fifth embodiment. [Figure 18] FIG. 13 is a circuit diagram of a power receiving device according to a sixth embodiment. [Figure 19] FIG. 13 is a circuit diagram of a power receiving device according to a seventh embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] A. First embodiment: A1. Configuration of the wireless power supply system: As shown in FIG. 1, the contactless power supply system 1 includes a power transmission device 10 and a power receiving device 80. In this embodiment, the power transmission device 10 is buried under a road RS. The power receiving device 80 is mounted on a vehicle VE as a moving body that travels on the road RS. When the vehicle VE is traveling, power is supplied to the power receiving device 80 from the power transmission device 10. Here, traveling includes a case where the vehicle VE is moving and a case where the vehicle is stopped, such as waiting at a traffic light. The vehicle VE is configured as, for example, an electric vehicle or a hybrid vehicle.

[0014] The power transmission device 10 includes a primary resonant circuit 12 having a primary coil L1, and an AC power source 11 that supplies power to the primary resonant circuit 12. The AC power source 11 supplies power to the multiple primary resonant circuits 12. The multiple primary coils L1 are arranged along the extension direction of the road RS.

[0015] The moving body on which the power receiving device 80 is mounted is not limited to a vehicle VE traveling on the road RS, and may be, for example, an AGV (automated guided vehicle), a traveling robot, etc. The power transmitting device 10 may be installed not under the road RS, but on a sidewalk or parking lot adjacent to the road RS, or on a route along which the AGV travels.

[0016] The power receiving device 80 includes a battery 84, an auxiliary battery 94, a pulse generating circuit 82, a secondary resonant circuit 81 having a secondary coil L2, a DC / DC converter 92, an inverter 91, a motor generator 93, an auxiliary 95, a power receiving control unit 96, and a vehicle speed sensor 97 as a speed acquisition unit. In this embodiment, the secondary coil L2 is provided on the underside of the vehicle VE, facing the primary coil L1.

[0017] A pulse generating circuit 82 is connected to the secondary resonant circuit 81. In this embodiment, the pulse generating circuit 82 functions as a rectifier in a power receiving state of the power receiving device 80, which will be described later, and functions as an inverter in a non-power receiving state of the power receiving device 80, which will be described later. In the power receiving state, the pulse generating circuit 82 converts AC power received by the secondary 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.

[0018] Battery 84 is a secondary battery that is charged by the supplied DC power. Inverter 91 drives motor generator 93 using the supplied DC power. Motor generator 93 operates as a three-phase AC motor and generates driving force for traveling. In addition, motor generator 93 operates as a generator when vehicle VE decelerates and regenerates power. The regenerated three-phase AC power is converted to DC power by inverter 91 and used to charge battery 84.

[0019] The DC / DC converter 92 steps down the DC power supplied from the pulse generating circuit 82, and supplies the stepped-down DC power to an auxiliary battery 94 and an auxiliary 95. The auxiliary 95 includes an air conditioner, an electric power steering device, peripheral devices such as headlights, blinkers, and wipers of the vehicle VE, and accessories of the vehicle VE. The auxiliary battery 94 is a secondary battery for driving the auxiliary 95. The vehicle speed sensor 97 detects the moving speed of the vehicle VE, and outputs a signal indicating the detected moving speed to the power receiving side control unit 96.

[0020] The power receiving side control unit 96 controls each unit such as the inverter 91 in the power receiving device 80. The power receiving side control unit 96 is realized by including an ECU (engine control unit). The ECU may be realized by one microcontroller or may be realized by including multiple microcontrollers. The case where multiple microcontrollers are included is the case where, for example, the ECU includes 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 pulse generating circuit 82.

[0021] A2.Circuit configuration of the non-contact power supply system: As shown in Fig. 2, in addition to the above configuration, the power transmission device 10 includes a primary side capacitor C1 which is a variable capacitance capacitor, a primary side voltage sensor M1 as a primary side detection circuit, a primary side control circuit 13, and a detected unit 14. The primary side coil L1 and the primary side capacitor C1 are connected in series to configure a primary side resonant circuit 12. Note that, in Fig. 2, only one primary side resonant circuit 12 out of the multiple primary side resonant circuits 12 connected to the AC power supply 11 is shown, and the other primary side resonant circuits 12 are not shown.

[0022] The AC power source 11 applies AC power of a predetermined operating frequency to the primary side resonant circuit 12. In this embodiment, the operating frequency is 85 kHz. The primary side capacitor C1 has a function of making the primary side resonant circuit 12 resonate at the operating frequency and making the primary side resonant circuit 12 non-resonate at the operating frequency. In this embodiment, the primary side capacitor C1 is configured to be switchable between a first capacitance value and a second capacitance value smaller than the first capacitance value. The capacitance value of the primary side capacitor C1 is switched between the first capacitance value and the second capacitance value by a switching signal Sig1 output from the primary side control circuit 13. When the primary side coil L1 and the secondary side coil L2 are magnetically coupled and the primary side capacitor C1 has the first capacitance value, the primary side resonant circuit 12 resonates at the operating frequency. That is, the first capacitance value of the primary side capacitor C1 is set to a value at which the resonant frequency of the primary side resonant circuit 12 coincides with the operating frequency. On the other hand, when the primary side capacitor C1 has the second capacitance value, the resonant frequency of the primary side resonant circuit 12 deviates from the operating frequency, so that the primary side resonant circuit 12 is in a non-resonant state at the operating frequency.

[0023] The primary voltage sensor M1 is provided to detect the magnitude of the magnetic flux interlinked with the primary coil L1. The primary voltage sensor M1 detects a voltage induced in the primary coil L1 due to a change in the magnetic flux interlinked with the primary coil L1. The primary voltage sensor M1 detects a voltage value of the primary coil L1 and outputs a signal indicating the detected voltage value to the primary control circuit 13. The primary control circuit 13 outputs a switching signal Sig1 to the primary capacitor C1 using the signal output from the primary voltage sensor M1. Specifically, the primary control circuit 13 outputs the switching signal Sig1 when the voltage value indicated by the signal is greater than a predetermined threshold value.

[0024] The primary side detection circuit is not limited to a configuration that detects the voltage of the primary side coil L1, and may be a current sensor that detects the current flowing through the primary side coil L1. Alternatively, the primary side detection circuit may be a magnetic sensor that detects the magnitude of magnetic flux near the primary side coil L1, more specifically, a magnetic sensor with a built-in coil provided near the primary side coil L1. If the primary side detection circuit is a magnetic sensor, the power transmitting device 10 transitions from the standby state to the power transmitting state in step S4 described later when an increase in magnetic flux near the primary side coil L1 is detected.

[0025] The detected portion 14 is a two-dimensional code displayed on the surface of the road RS. As the two-dimensional code, various types of two-dimensional code such as QR code (registered trademark), micro QR code, iQR code, PDF417, etc. can be used.

[0026] In addition to the above configuration, the power receiving device 80 has a secondary capacitor C2, a secondary voltage sensor M2 as a secondary detection circuit, a secondary control circuit 85, and a device detection unit 87. The secondary coil L2 and the secondary capacitor C2 are connected in series to configure a secondary resonant circuit 81. In this embodiment, the secondary coil L2 functions as a power receiving coil and also functions as a magnetic flux generating coil for generating a magnetic flux to be radiated to the primary coil L1. The secondary coil L2 as a magnetic flux generating coil, the pulse generating circuit 82, and the secondary control circuit 85 configure a magnetic flux generating circuit 86.

[0027] The pulse generating circuit 82 is configured as a synchronous rectifier circuit. Specifically, the pulse generating circuit 82 has four switching elements Q1, Q2, Q3, and Q4 and a smoothing capacitor C3. The four switching elements Q1, Q2, Q3, and Q4 configure a bridge circuit. As a result, in a power receiving state in which AC power is supplied from the secondary side resonant circuit 81, the circuit functions as a rectifier, and in a power non-receiving state in which DC power is supplied from the battery 84, the circuit functions as an inverter. In this embodiment, the switching elements Q1 to Q4 are realized by MOSFETs (metal-oxide-semiconductor field-effect transistors). The pulse generating circuit 82 will be described in detail later. The power source of the secondary side control circuit 85 and the device detection unit 87 is the battery 84.

[0028] The secondary-side voltage sensor M2 serving as a secondary-side detection circuit is a voltage detection circuit that detects the output voltage value of the battery 84 and outputs a signal indicating the detected output voltage value to the secondary-side control circuit 85. The secondary-side control circuit 85 drives the pulse generation circuit 82 using the signal output from the secondary-side voltage sensor M2. Specifically, the pulse generation circuit 82 inputs a control signal to each of the gate terminals of the switching elements Q1 to Q4. The driving performed by the secondary-side control circuit 85 will be described in detail later.

[0029] The device detection unit 87 detects the detected unit 14. The device detection unit 87 is a two-dimensional code reader capable of reading two-dimensional codes. In this embodiment, the device detection unit 87 detects a QR code (registered trademark) by imaging. If the detected QR code (registered trademark) is a predetermined code, the device detection unit 87 outputs a signal Sig2 to the secondary side control circuit 85. When the signal Sig2 is input, the secondary side control circuit 85 drives the pulse generation circuit 82 to supply AC power to the pulse generation circuit 82.

[0030] When the primary coil L1 and the secondary coil L2 are magnetically coupled, the resonant frequency of the primary resonant circuit 12 and the resonant frequency of the secondary resonant circuit 81 are set to be substantially the same. This allows contactless power supply to the power receiving device 80 by magnetic field resonance between the primary coil L1 and the secondary coil L2. As described above, the DC power output from the secondary resonant circuit 81 is rectified by the pulse generating circuit 82 and supplied to the battery 84.

[0031] A3. Standby and power transmission states: As shown in FIG. 3, the primary coils L1 are arranged in the direction in which the road RS extends, and the secondary coils L2 receive power from the nearest primary coil L1 in a non-contact manner. In FIG. 3, the primary coils L1 and the secondary coils L2 that are transferring power are shown hatched. That is, the primary coils L1 that are not hatched are the primary coils L1 in a standby state, and the primary coils L1 that are hatched are the primary coils L1 in a power transmission state. The arrows shown in FIG. 3 indicate the traveling direction of the vehicle VE in which the secondary coils L2 are mounted. At "time t1" shown in FIG. 3, the secondary coils L2 approach the arranged primary coils L1. As shown in FIG. 3 at "time t2", when the secondary coils L2 approach the primary coils L1 at the end, a power supply start sequence, which will be described later, is performed, and non-contact power supply is started. As shown at "time t3" in Figure 3, when the vehicle VE travels and the distance between the primary coil L1 and the secondary coil L2 next to the terminal primary coil L1 becomes shorter than the distance between the terminal primary coil L1 and the secondary coil L2, the primary coil L1 that exchanges power switches from the terminal primary coil L1 to the primary coil L1 next to the terminal primary coil L1.

[0032] In addition, power is exchanged not only when the entire primary coil L1 faces the secondary coil L2 in the direction of the coil center axis of the primary coil L1, as shown at "time t3" in Figure 3, but also when only a portion of the primary coil L1 faces the secondary coil L2, as shown at "time t2" in Figure 3.

[0033] A4. Power supply start sequence: The contactless power supply system 1 starts and stops power supply between the power transmitting device 10 and the power receiving device 80 without using communication. In this embodiment, the power receiving side control unit 96 outputs a power supply permission signal to the secondary side control circuit 85 when permitting power reception by the secondary side resonant circuit 81. Then, the power receiving side control unit 96 outputs a power supply prohibition signal to the secondary side control circuit 85 when prohibiting power supply by the secondary side resonant circuit 81. The power receiving side control unit 96 outputs the power supply prohibition signal when, for example, the state of the battery 84 is not suitable for charging. In the following description, each step will be used to make it easier to understand.

[0034] 4, the device detector 87 of the power receiving device 80 detects the detected unit 14 of the power transmitting device 10. When the device detector 87 detects the detected unit 14, it outputs a signal Sig2 to the secondary-side control circuit 85.

[0035] When the signal Sig2 is input, the secondary control circuit 85 checks in step S2 whether a power supply permission signal has been input. If the power supply permission signal has been input, the device detection unit 87 drives the pulse generation circuit 82 to supply AC power at the resonant frequency or a frequency close to the resonant frequency to the secondary coil L2. As a result, in step S3 of FIG. 4, the secondary coil L2 functioning as a magnetic flux generating coil generates magnetic flux. As a result, the magnetic flux linking the primary coil L1 increases, and an electromotive force is generated in the primary coil L1 by electromagnetic induction, and the voltage of the primary coil L1 increases.

[0036] If a power supply prohibition signal is input instead of a power supply permission signal, the secondary-side control circuit 85 does not perform step S3 and sets the pulse generating circuit 82 to a stopped state, which will be described later. This makes it possible to avoid power supply when the battery 84 is not in a state suitable for charging. As another embodiment, if a power supply prohibition signal is input, the secondary-side control circuit 85 may not perform step S3, but may transition to a permission signal waiting state in which it waits for the input of a power supply permission signal, and may start driving using the input of a power supply start signal as a trigger to execute step S3. This makes it possible to receive power supply by inputting the power supply start signal, even if a power supply prohibition signal is input when the signal Sig2 is input.

[0037] When an increase in the magnetic flux linking the primary coil L1 is detected in step S4 of FIG. 4, the primary control circuit 13 outputs a switching signal Sig1 to the primary capacitor C1. Specifically, when the primary control circuit 13 determines that the voltage value indicated by the signal output from the primary voltage sensor M1 is greater than the threshold value, it outputs the switching signal Sig1 to the primary capacitor C1. As a result, in step S5 of FIG. 4, the capacitance value of the primary capacitor C1 as an impedance variable element is switched from the second capacitance value to the first capacitance value. As a result, the primary resonant circuit 12 is in a resonant state at the resonant frequency fs, transitions to a power transmission state in which a power transmission current flows through the primary coil L1, and power supply is started. In this way, when an increase in the magnetic flux linking the primary coil L1 is detected by the primary voltage sensor M1, the power transmitting device 10 transitions from the standby state to the power transmission state. At the point in time when the capacitance value of the primary capacitor C1 is switched, the power transmitting device 10 transitions from the standby state to the power transmission state. In step S6 as a switching process, the driving method of the pulse generating circuit 82 is switched from pause driving, which will be described later, to rectification driving, which causes the pulse generating circuit 82 to function as a rectifier. As a result, the power receiving device 80 transitions from a non-power receiving state to a power receiving state. In detail, the secondary side control circuit 85 detects the start of power transmission by the power transmitting device 10 by detecting a current flowing in a current path passing through the body diode of the switching element Q1 and the body diode of the switching element Q4 due to an electromotive force generated in the secondary side coil L2, for example, by a voltage sensor (not shown) that detects a source-drain voltage of the switching element Q4. Then, in the power receiving state, the secondary side control circuit 85 rectifies and drives the pulse generating circuit 82 in accordance with the phase of the AC power received by the secondary side coil L2 so that the pulse generating circuit 82 functions as a rectifier. As described above, the contactless power supply between the power transmitting device 10 and the power receiving device 80 is started without using communication, and therefore contactless power supply can be started earlier than when communication is used to start power supply.

[0038] A5. Control by secondary control circuit: In step S3 of FIG. 3, the pulse generating circuit 82 converts the DC power supplied from the battery 84 into AC power and inputs it to the secondary resonant circuit 81. Here, the output voltage value of the battery 84 may deviate from the target voltage value Vtg (FIG. 6). In addition, the value of the current flowing through the secondary coil L2 is proportional to the output voltage value of the battery 84. For this reason, when the output voltage value of the battery 84 is lower than the target voltage value Vtg, in step S3, the magnetic flux generated by the secondary coil L2 becomes smaller than the target magnetic flux, and even though the secondary coil L2 approaches, the magnetic flux interlinked with the primary coil L1 becomes smaller, and power supply may not be started. On the other hand, when the output voltage value of the battery 84 is higher than the target voltage value Vtg, in step S3, the magnetic flux generated by the secondary coil L2 becomes larger than the target magnetic flux, and this may cause a malfunction in the primary resonant circuit 12. Therefore, in this embodiment, the pulse generating circuit 82 is appropriately driven using the output power value of the battery 84. This makes it possible to appropriately set the magnitude of the magnetic flux generated in the secondary coil L2 in step S3.

[0039] As described above, the pulse generating circuit 82 shown in FIG. 2 has four switching elements Q1, Q2, Q3, and Q4. When the secondary side control circuit 85 causes the pulse generating circuit 82 to function as an inverter, the secondary side control circuit 85 drives the switching elements Q1 and Q2 constituting the upper arm connected to the positive terminal of the battery 84 in a complementary manner. Similarly, the secondary side control circuit 85 drives the switching elements Q3 and Q4 constituting the lower arm connected to the negative terminal of the battery 84 in a complementary manner. The switching elements Q1 and Q4 are set to an on state by simultaneously receiving an on signal, and are set to an off state by simultaneously receiving an off signal. Similarly, the switching elements Q2 and Q3 are set to an on state by simultaneously receiving an on signal, and are set to an off state by simultaneously receiving an off signal.

[0040] FIG. 5 is a diagram showing the waveforms of the control signals input to the switching elements Q1 and Q4. As shown in FIG. 5, in the non-power receiving state, the secondary side control circuit 85 periodically repeats a supply drive for causing the pulse generating circuit 82 to supply AC power to the secondary side coil L2 and a pause drive for causing the pulse generating circuit 82 to pause the supply of AC power to the secondary side coil L2. In detail, the secondary side control circuit 85 performs a burst drive in which a drive period Td in which an ON signal is output and a pause period Tp in which an ON signal is not output are periodically repeated in a second period T2. As a result, the pulse generating circuit 82 is driven intermittently. That is, the secondary side control circuit 85 outputs an ON signal to the pulse generating circuit 82 in the supply drive and does not output an ON signal to the pulse generating circuit 82 in the pause drive. Here, the ON signal is a high-level signal for turning the switching element Q1 ON in the case of the switching element Q1. Also, the OFF signal is a low-level signal for turning the switching element Q1 OFF in the case of the switching element Q1. The same is true for the switching elements Q2 to Q3. During the pause period Tp, an OFF signal is output to the switching elements Q1 to Q4. The secondary-side control circuit 85 adjusts the frequency and duty ratio of the control signal input to the pulse generating circuit 82. Here, the duty ratio is the ratio of an ON period Ton during which an ON signal is output to a first cycle T1 during the drive period Td.

[0041] When the frequency of the AC power input to the secondary resonant circuit 81 is the resonant frequency fs (FIG. 6), the current flowing through the secondary coil L2 is maximum. When the frequency of the AC power input to the secondary resonant circuit 81 deviates from the resonant frequency fs, the current flowing through the secondary coil L2 changes according to the frequency. Therefore, when the output voltage value of the battery 84 deviates from the target voltage value Vtg, the current flowing through the secondary coil L2 can be adjusted by adjusting the drive frequency of the pulse generating circuit 82. The drive frequency of the pulse generating circuit 82 is (1 / T1) using the first period T1.

[0042] Moreover, by adjusting the duty ratio of the control signal input to the pulse generating circuit 82, it is possible to adjust the effective voltage of the AC power input to the secondary resonant circuit 81. This makes it possible to adjust the current flowing through the secondary coil L2. Specifically, the smaller the duty ratio is, the smaller the effective voltage of the AC power input to the secondary resonant circuit 81 becomes, and the smaller the current flowing through the secondary coil L2 becomes.

[0043] Fig. 6 is a diagram showing the relationship between the drive frequency (horizontal axis) and the current flowing through the secondary coil L2 (vertical axis). The characteristic line Ds shown in Fig. 6 is a characteristic line when the output voltage value of the battery 84 is the target voltage value Vtg. The characteristic line D1 is a characteristic line when the output voltage value of the battery 84 is smaller than the target voltage value Vtg. The characteristic line D1 is a characteristic line when the voltage of the battery 84 is smaller than the target voltage value Vtg. The duty ratios of the characteristic lines Ds, D1, and D2 are all the same, a reference duty ratio.

[0044] As shown in FIG. 6, the target current value Itg, which is the target value of the current value flowing through the secondary coil L2, is the current value flowing through the secondary coil L2 when the output voltage value of the battery 84 is the target voltage value Vtg, the drive frequency is the reference frequency fd, and the duty ratio is driven at the reference duty ratio. The reference frequency fd is smaller than the resonance frequency fs. When the output voltage value of the battery 84 is higher than the target voltage value Vtg, the secondary control circuit 85 reduces the voltage value supplied to the secondary coil L2 by lowering the duty ratio from the reference duty ratio. This allows the current value flowing through the secondary coil L2 to be adjusted to the target current value Itg. On the other hand, when the output voltage value of the battery 84 is lower than the target voltage value Vtg, the secondary control circuit 85 increases the drive frequency from the reference frequency fd to approach the resonance frequency fs. This allows the current flowing through the secondary coil L2 to be adjusted to the target current value Itg. Therefore, even if the output voltage value of the battery 84 deviates from the target voltage value Vtg, an appropriate current can be supplied to the secondary coil L2. In this embodiment, the reference duty ratio is 50%.

[0045] The driving method when the output voltage value of the battery 84 deviates from the target voltage value Vtg is not limited to the above. In the above, the duty ratio is adjusted when the output voltage value is higher than the target voltage value Vtg, and the driving frequency is adjusted when the output voltage value is lower than the target voltage value Vtg, but regardless of whether the output voltage value is higher or lower than the target voltage value Vtg, the current value flowing through the secondary coil L2 can be adjusted to the target current value Itg by adjusting at least one of the driving frequency and the duty ratio.

[0046] Furthermore, the secondary control circuit 85 stops the supply of AC power by the pulse generating circuit 82 when the detection value of the secondary voltage sensor M2 is outside a predetermined range. Specifically, as shown in FIG. 4, when the detection value of the secondary voltage sensor M2 is smaller than the first threshold Vth1 and larger than the second threshold Vth2, the operation of the pulse generating circuit 82 is stopped. Specifically, an off signal is input to all of the switching elements Q1 to Q4. When the output voltage value of the battery 84 is smaller than the first threshold Vth1, for example, the battery 84 may not be properly connected. When the battery voltage is larger than the second threshold Vth2, for example, an abnormality may occur in the battery 84. In such an abnormal state, the current supply to the secondary coil L2 is stopped, so that the power transmitting device 10 transitions to a power transmitting state and the secondary resonant circuit 81 starts receiving power, thereby preventing the occurrence of an overvoltage in the secondary control circuit 85.

[0047] Furthermore, in the non-contact power supply system 1, a measure is taken so that the magnetic flux generated by the secondary coil L2 and the magnetic flux generated by the primary coil L1 do not overlap. Specifically, as shown in the "first case" of FIG. 7, the period from step S4 to step S5 in the power transmission device 10 is set to be longer than the driving period Td in the power receiving device 80. As described above, the secondary control circuit 85 drives the pulse generating circuit 82 during the driving period Td. That is, during the driving period Td, magnetic flux is continuously generated in the secondary coil L2. After the primary voltage sensor M1 detects an increase in the magnetic flux linking the primary coil L1 in step S4, the power transmission device 10 transitions to a power transmission state by performing step S5 after a standby time has elapsed. The standby time is longer than the response time for the primary control circuit 13 to perform step S4. The standby time is a predetermined time for the power transmitting device 10 to transition to a power transmitting state during the pause period Tp of the power receiving device 80. As a result, even if step S4 is performed at the start of the drive period Td, step S5 is performed during the pause period Tp. Note that, as shown in the "second case" of FIG. 7, the length of the standby time is set so that step S5 is performed during the pause period Tp even if step S4 is performed at the end of the drive period Td. As a result, it is possible to avoid the overlapping of the magnetic flux generated by the secondary coil L2 and the magnetic flux generated by the primary coil L1, thereby avoiding the occurrence of an overvoltage and an overcurrent.

[0048] Furthermore, the secondary control circuit 85 adjusts the period of the pause drive, specifically, the length of the pause period Tp, using the vehicle speed. As shown in FIG. 8, when the vehicle speed is higher than the reference speed, the pause period Tp is made longer than the reference length. On the other hand, when the vehicle speed is lower than the reference speed, the pause period Tp is made shorter than the reference length. In the non-contact power supply system 1, when the secondary coil L2 approaches a position where non-contact power supply is possible from the primary coil L1, non-contact power supply is started. The change over time of the distance between the primary coil L1 and the secondary coil L2 depends on the moving speed of the vehicle VE. Therefore, by adjusting the pause period Tp according to the moving speed, step S3 can be performed at appropriate time intervals in response to the change over time of the distance between the primary coil L1 and the secondary coil L2. Specifically, the time of the pause period Tp is set using a map in which the relationship between the vehicle speed and the time of the pause period Tp is previously associated. This map is stored in the power receiving side control unit 96, and the duration of the pause period Tp determined using the map is output from the power receiving side control unit 96 to the secondary side control circuit 85. As another embodiment, this map may be stored in the secondary side control circuit 85, and the secondary side control circuit 85 may set the duration of the pause period Tp using a signal indicating the vehicle speed output from the power receiving side control unit 96.

[0049] According to the first embodiment described above, when the primary voltage sensor M1 detects an increase in the magnetic flux linking the primary coil L1, the power transmitting device 10 transitions from a standby state to a power transmitting state. This allows for early start of contactless power supply. In addition, the magnetic flux generating circuit 86 adjusts the magnitude of the magnetic flux generated by the secondary coil L2 using the detection value of the secondary voltage sensor M2. This allows for appropriate adjustment of the magnetic flux density of the magnetic flux generated in the secondary coil L2 to cause the power transmitting device 10 to start power transmission.

[0050] Furthermore, in a non-power-receiving state, the secondary-side control circuit 85 adjusts the magnitude of the generated magnetic flux using a voltage value detected by the primary-side voltage sensor M1 that detects the output voltage value of the battery 84. This makes it possible to appropriately adjust the magnetic flux generated in the secondary-side coil L2 even if the output voltage value of the battery 84 deviates from the target voltage value Vtg.

[0051] Moreover, the secondary-side control circuit 85 adjusts the generated magnetic flux by adjusting at least one of the drive frequency and the duty ratio of the pulse generating circuit 82. This allows the secondary-side control circuit 85 to adjust the generated magnetic flux by adjusting either the drive frequency or the duty ratio.

[0052] Furthermore, when the detection value of the secondary-side voltage sensor M2 is smaller than the first threshold value Vth1 and larger than the second threshold value Vth2, the secondary-side control circuit 85 stops the supply of AC current by the pulse generating circuit 82. As a result, when an abnormality occurs in the power receiving device 80, the operation of the pulse generating circuit 82 is stopped, the power transmitting device 10 transitions to a power transmitting state, and the secondary-side resonant circuit 81 starts receiving power, thereby preventing the occurrence of an overvoltage in the secondary-side control circuit 85.

[0053] In addition, after the primary detection circuit detects an increase in magnetic flux near the primary coil L1 in step S4, the power transmitting device 10 transitions to a power transmitting state after a standby time has elapsed in step S5. This makes it possible to avoid the overlap of magnetic flux generated by the secondary coil L2 and the primary coil L1, thereby avoiding the occurrence of overvoltage and overcurrent.

[0054] Furthermore, if a power supply prohibition signal has been input, the secondary-side control circuit 85 does not perform step S3. This makes it possible to avoid power supply when the battery 84 is not in a state suitable for charging. If a power supply prohibition signal has been input, the secondary-side control circuit 85 does not execute step S3, but transitions to an enable signal standby state in which it waits for the input of a power supply permission signal, and executes step S3 using the input of a power supply start signal as a trigger. This makes it possible to receive power supply by inputting the power supply start signal, even if a power supply prohibition signal has been input when the signal Sig2 is input.

[0055] Moreover, the secondary control circuit 85 adjusts the length of the pause period Tp in accordance with the vehicle speed, so that the secondary control circuit 85 can perform step S3 at appropriate time intervals in response to the change over time in the distance between the primary coil L1 and the secondary coil L2.

[0056] B. Second embodiment: 9, the contactless power supply system 201 according to this embodiment differs from the first embodiment in the circuit configuration of the power transmitting device 210 and the circuit configuration of the power receiving device 280. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate.

[0057] The power transmitting device 210 according to this embodiment is different from the power transmitting device 10 according to the first embodiment in the configuration for changing the impedance of the primary side resonant circuit 212. The power transmitting device 210 has a first switch SW1 and capacitors C21 and C22. The capacitor C22 is connected in parallel with the connection between the first switch SW1 and the capacitor C21. The capacitance value of the capacitor C22 is smaller than the capacitance value of the capacitor C21. A switching signal Sig3 is input from the control circuit 50 to the first switch SW1.

[0058] When a high-level switching signal Sig3 is input to the first switch SW1, the first switch SW1 is turned on and a current flows through the capacitor C21. Here, the combined capacitance of the capacitors C21 and C22 and the inductance of the primary coil L1 are set to values ​​that provide a resonant state at the operating frequency. As a result, when the first switch SW1 is turned on, the capacitors C21, C22, and the primary coil L1 form a primary resonant circuit 212, which is a series resonant circuit. On the other hand, when a low-level switching signal Sig3 is input to the first switch SW1, the first switch SW1 is turned off and the capacitor C21 is in a non-conducting state. Then, the resonant frequency of the resonant circuit formed by the capacitor C22 and the primary coil L1 deviates from the operating frequency, so the primary coil L1 is in a standby state. In addition, since the capacitance value of the capacitor C22 is smaller than the capacitance value of the capacitor C21, when the first switch SW1 is in the off state, the impedance of the primary side resonant circuit 212 with respect to the input AC power increases, suppressing the current flowing through the primary side resonant circuit 212. In the standby state, the current flowing through the primary side coil L1 is called a standby current.

[0059] The power receiving device 280 according to this embodiment has a magnetic flux detection circuit 281 as a secondary detection circuit that detects the magnitude of the magnetic flux radiated from the primary coil L1, instead of the secondary voltage sensor M2 according to the first embodiment. The magnetic flux detection circuit 281 detects the magnitude of the magnetic flux generated from the primary coil L1. Specifically, the magnetic flux detection circuit 281 incorporates a detection coil Lsp arranged near the secondary coil L2, and detects the magnitude of the magnetic flux density using the voltage of the detection coil Lsp. The magnetic flux detection circuit 281 outputs a signal Sig4 indicating the magnitude of the detected magnetic flux density to the secondary control circuit 285. In detail, the detection coil Lsp is arranged at a position where it is magnetically coupled to the primary coil L1 when the primary coil L1 and the secondary coil L2 are magnetically coupled. As a result, the detection coil Lsp can detect the magnitude of the magnetic flux linking the primary coil L1 when the secondary coil L2 is not generating magnetic flux. Note that "detecting the magnitude of the magnetic flux linking the primary coil L1" does not only mean detecting all of the magnetic flux linking the primary coil L1, but also means detecting a part of the magnetic flux linking the primary coil L1 as in this embodiment. In this embodiment, the magnetic flux density detected by the secondary voltage sensor M2 decreases as the distance from the primary coil L1 increases. In other words, the detection value of the secondary voltage sensor M2 varies depending not only on the magnitude of the magnetic flux generated by the primary coil L1 but also on the distance between the primary coil L1 and the secondary voltage sensor M2.

[0060] The power supply start sequence of this embodiment is different from that of the first embodiment. In the standby state of the power transmitting device 10 shown in Fig. 10, the first switch SW1 is set to the off state, so that a standby current flows through the primary coil L1. In step S21, the standby current flows through the primary coil L1, so that the primary coil L1 generates a magnetic flux.

[0061] When the secondary coil L2 approaches the primary coil L1, the magnetic flux density detected by the magnetic flux detection circuit 281 increases in step S22. When the magnetic flux density indicated by the signal Sig4 exceeds a predetermined threshold, the secondary control circuit 285 outputs an ON signal to the pulse generation circuit 82 to drive it. As a result, in step S25, the secondary coil L2 as a magnetic flux generation coil generates magnetic flux. As a result, the magnetic flux linking the primary coil L1 is amplified.

[0062] When the primary side control circuit 13 determines in step S26 that the magnetic flux linking the primary side coil L1 has been amplified based on the detection value of the primary side voltage sensor M1 as the primary side detection circuit, it switches the voltage level of the switching signal Sig3. Specifically, when it determines that the voltage value indicated by the signal output from the primary side voltage sensor M1 is greater than the threshold value, it outputs a high-level switching signal Sig3 to the first switch SW1. As a result, in step S25, the combined capacitance of the capacitors C21 and C22 as the impedance variable elements is changed. As a result, the primary side resonant circuit 212 enters a resonant state at the operating frequency, and power supply is started.

[0063] In this embodiment, after supplying and driving the pulse generating circuit 82, the secondary side control circuit 285 continues the pause driving for a predetermined time or more when the detection value of the magnetic flux detection circuit 281 is within a predetermined magnetic flux range. Specifically, after performing step S25, the secondary side control circuit 285 performs step S28 during the pause period Tp. In step S28, the secondary side control circuit 285 determines whether the magnetic flux density indicated by the signal Sig4 output from the magnetic flux detection circuit 281 is greater than a predetermined first threshold value. Then, when the magnetic flux density indicated by the signal Sig4 is greater than the first threshold value, the secondary side control circuit 285 does not change the time of the predetermined pause period Tp because the power transmitting device 210 is transmitting power. In this case, that is, when the power transmitting device 210 is transmitting power, the secondary side control circuit 285 detects the power reception at the secondary side coil L2 using a voltage sensor (not shown) to cause the pulse generating circuit 82 to function as a rectifier. On the other hand, when the magnetic flux density indicated by the signal Sig4 is equal to or less than the first threshold, the power transmitting device 210 is not transmitting power, or the distance between the primary coil L1 and the secondary coil L2 is long enough that the secondary coil L2 cannot receive the transmitted power, so the secondary control circuit 285 extends the time of the predetermined pause period Tp and continues the pause drive for a predetermined period or more. By extending the period of the pause operation in which the pulse generating circuit 82 is not driven, it is possible to suppress power consumption of the battery 84. Note that the secondary control circuit 285 may drive the pulse generating circuit 82 after continuing the pause drive for a predetermined period or more, and may further continue the pause drive for a predetermined period or more. As described above, being within the magnetic flux range means that the detection value is equal to or less than the first threshold.

[0064] Moreover, the secondary side control circuit 285 stops the supply drive when the detection value of the magnetic flux detection circuit 281 is outside a predetermined range. Specifically, the secondary side control circuit 285 judges whether or not the magnetic flux density indicated by the signal Sig4 output from the magnetic flux detection circuit 281 is greater than a predetermined second threshold value. The second threshold value is a value greater than the first threshold value. The secondary side control circuit 285 stops the supply drive when the magnetic flux density indicated by the signal Sig4 is greater than the second threshold value. This makes it possible to avoid the occurrence of a malfunction in the primary side resonant circuit 212 caused by an increase in the electromotive force induced in the primary side coil L1 by the magnetic flux generated by the secondary side coil L2. As described above, the outside of the predetermined range refers to a case where the detection value is greater than the second threshold value.

[0065] In this embodiment, as in the first embodiment, the secondary control circuit 285 adjusts the drive frequency and duty ratio of the pulse generating circuit 82. However, while the secondary control circuit 85 in the first embodiment adjusts using the detection value of the secondary voltage sensor M2, the secondary control circuit 285 in this embodiment adjusts using the detection value of the magnetic flux detection circuit 281. The detection value of the secondary voltage sensor M2 increases as the distance between the primary coil L1 and the secondary coil L2 is closer and the coupling coefficient between the primary coil L1 and the secondary coil L2 is larger. Therefore, as in the first embodiment, when the coupling coefficient between the primary coil L1 and the secondary coil L2 is larger than a predetermined threshold value, at least one of the drive frequency and the duty ratio of the pulse generating circuit 82 is adjusted so that the magnetic flux generated by the secondary coil L2 does not become excessively large.

[0066] Specifically, the secondary-side control circuit 285 receives an input of a signal indicating the magnetic flux density detected in step S22 shown in Fig. 10, and when the magnetic flux density is equal to or greater than the first threshold value and less than the second threshold value, calculates a coupling coefficient in step S23 shown in Fig. 11. The secondary-side control circuit 285 calculates the coupling coefficient using a calculation formula stored in advance in a built-in memory.

[0067] The equivalent circuit shown in the upper part of FIG. 12 is the equivalent circuit used to derive the formula for calculating the coupling coefficient. m The bottom part of Fig. 12 shows the mutual inductance L m The derivation process of equation (5) for calculating

[0068] The current I1 of the primary coil satisfies the formula (1) shown in the lower part of FIG. 12. The current I2 of the secondary coil satisfies the formula (2). The voltage V of the secondary coil when the secondary resonant circuit is not resonating L2 satisfies equation (3). Equation (4) is obtained by substituting equation (2) for current I2 in equation (3). Equation (4) can be rearranged to obtain equation (5). Current I1 in equation (5) is the standby current value and is known. The values ​​of the other parameters are also known, so the voltage V of the secondary coil can be calculated as follows: L2 By giving the mutual inductance L m The value of the mutual inductance L m The coupling coefficient k can be calculated from the value of the inductance L1 of the primary coil and the value of the inductance L2 of the secondary coil. L2 A map showing the relationship between the voltage V of the secondary coil and the magnetic flux detection circuit 281 is stored in advance in the memory of the secondary control circuit 285. The secondary control circuit 285 uses this map to convert the detection value of the magnetic flux detection circuit 281 into the voltage V of the secondary coil. L2 The coupling coefficient k is calculated by converting the inductances L1 and L2 into the following equation:

[0069] The secondary side control circuit 285 changes the driving of the pulse generating circuit 82 depending on whether the calculated coupling coefficient k is greater than a predetermined threshold value. If step S24 is "NO", that is, if the calculated coupling coefficient k is not greater than the predetermined threshold value, the secondary side control circuit 285 drives the pulse generating circuit 82 in step S25a so that the generated magnetic flux becomes the target magnetic flux. On the other hand, if step S24 is "YES", that is, if the calculated coupling coefficient k is greater than the predetermined threshold value, the secondary side control circuit 285 drives the pulse generating circuit 82 in step S25b so that the generated magnetic flux becomes smaller than the target magnetic flux. Specifically, the secondary side control circuit 285 controls the pulse generating circuit 82 so that the current flowing through the secondary side coil L2 becomes smaller. This makes it possible to avoid malfunctions in the primary side resonant circuit 212 caused by a large electromotive force induced in the primary side coil L1 by the magnetic flux generated by the secondary side coil L2 when the distance between the primary side coil L1 and the secondary side coil L2 is shorter than the design condition.

[0070] In addition, the secondary-side control circuit 85 performs maximum efficiency control using the calculated coupling coefficient k. The maximum efficiency control is a control for maximizing the power supply efficiency. Specifically, the secondary-side control circuit 285 adjusts the voltage of the AC power supplied to the secondary-side resonant circuit 81 by adjusting the drive frequency of the pulse generating circuit 82.

[0071] According to the second embodiment described above, the secondary side control circuit 285 drives the pulse generating circuit 82 using the magnetic flux detection circuit 281, thereby achieving the same effect as the first embodiment. After performing the supply drive, when the detection value of the magnetic flux detection circuit 281 is within the magnetic flux range, that is, when the detection value of the magnetic flux detection circuit 281 is equal to or less than the first threshold value, the secondary side control circuit 285 continues the pause drive for a predetermined time or more. This makes it possible to suppress the power consumption of the battery 84. Also, when the detection value of the magnetic flux detection circuit 281 is outside the range, that is, when the detection value of the magnetic flux detection circuit 281 is greater than the second threshold value, the supply of AC current to the secondary side coil L2 by the pulse generating circuit 82 is stopped. This makes it possible to avoid the occurrence of a malfunction in the primary side resonant circuit 212 caused by the increase in the electromotive force induced in the primary side coil L1 by the magnetic flux generated by the secondary side coil L2. Also, the secondary side control circuit 285 performs control to maximize the power supply efficiency using the calculated coupling coefficient k. This makes it possible to optimize the power supply efficiency in the contactless power supply system 1.

[0072] C. Third embodiment: 13, the contactless power supply system 301 according to this embodiment differs from the first embodiment in the circuit configuration of the power transmitting device 310 and the circuit configuration of the power receiving device 380. The same components as those in the above embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate.

[0073] The power transmitting device 310 according to this embodiment is different from the power transmitting device 10 according to the first embodiment in the configuration for changing the impedance of the primary side resonant circuit 12. The power transmitting device 310 has a second switch SW2 and capacitors C31 and C32. The capacitors C31 and C32 are connected in series. The second switch SW2 is connected to one terminal and the other terminal of the capacitor C31. The second switch SW2 shorts or opens the one terminal and the other terminal of the capacitor C31. A switching signal Sig5 is input from the control circuit 50 to the second switch SW2.

[0074] When a high-level switching signal Sig5 is input to the second switch SW2, the second switch SW2 is turned on. As a result, one terminal and the other terminal of the capacitor C31 are short-circuited, and the capacitor C31 is turned off. Here, the capacitance of the capacitor C32 and the inductance of the primary coil L1 are set to values ​​that are in a resonant state at the operating frequency. As a result, when the second switch SW2 is turned on, the capacitor C32 and the primary coil L1 form a primary resonant circuit 312, which is a series resonant circuit. On the other hand, when a low-level switching signal Sig5 is input to the second switch SW2, the second switch SW2 is turned off and the capacitor C31 is turned on. Then, the resonant frequency of the resonant circuit formed by the capacitors C31 and C32 and the primary coil L1 deviates from the operating frequency, so the primary coil L1 is in a standby state. Furthermore, since the combined capacitance value of capacitors C31 and C32 is smaller than the capacitance value of capacitor C32, when the second switch SW2 is in the off state, the impedance of the resonant circuit formed by capacitors C31, C32 and the primary coil L1 with respect to the input AC power becomes large, and the current flowing through the primary coil L1 is suppressed.

[0075] The power receiving device 380 according to this embodiment has a current sensor M3, instead of the secondary voltage sensor M2, that detects the value of a current flowing through a wire connected to the positive terminal of the battery 84. The current sensor M3 detects the value of a current flowing through the pulse generating circuit 82. The current sensor M3 is a current detection circuit that outputs a signal Sig6 indicating the detected current value to the secondary control circuit 385.

[0076] The current sensor M3 may be located on the wiring connected to the positive terminal of the battery 84, on the wiring N1 connected to the negative terminal of the battery 84, or on the wirings N2 and N3 connecting the secondary resonant circuit 81 and the pulse generating circuit 82. In other words, the current sensor M3 may detect the value of a current flowing through the pulse generating circuit 82, or may detect the value of a current flowing through the secondary coil L2.

[0077] The power supply start sequence of this embodiment differs from that of the first embodiment in that a processing step subsequent to step S2 of the first embodiment is added. As shown in Fig. 14, after the generation of magnetic flux in the secondary coil L2 serving as a magnetic flux generating coil (step S2), the secondary control circuit 385 uses the signal Sig6 in step S31 to determine whether or not the detection value of the current sensor M3 is outside a predetermined range.

[0078] Specifically, the out-of-range state is when the detected current as the detected value is greater than the first threshold value Ith1 and less than the second threshold value Ith2. When the detected current is greater than the first threshold value Vth1, a fault such as a broken wire in the secondary resonant circuit 81 is assumed. When the detected current is less than the second threshold value Ith2, a fault in the power transmitting device 310 is assumed, for example, and magnetic coupling between the primary coil L1 and the secondary coil L2 is not generated. Therefore, when the detected current is greater than the first threshold value Ith1 and less than the second threshold value Ith2, the secondary control circuit 385 stops the supply drive, and in step S32, outputs an abnormality signal notifying the abnormality to the power receiving side control unit 96 (FIG. 1). When the abnormality signal is input, the power receiving side control unit 96, for example, displays a message notifying the abnormality on a display device (not shown) mounted on the vehicle VE. This allows a passenger in the vehicle VE to know that there is an abnormality in the charging. Furthermore, if the power receiving side control unit 96 has a communication interface capable of communicating with the power transmitting device 310, the power receiving side control unit 96 may transmit a notification of the abnormality to the power transmitting device 310.

[0079] Furthermore, if the detected current is equal to or greater than the first threshold Ith1 and equal to or less than the second threshold Ith2 but is not the target current value Itg, it is assumed that a resonance deviation occurs. The resonance deviation refers to a state in which at least one of the capacitance value and the inductance of the secondary resonant circuit 81 deviates from the target capacitance value or the target inductance value, causing the resonant frequency of the secondary resonant circuit 81 to deviate from the operating frequency. Therefore, similar to the first embodiment, the secondary control circuit 385 adjusts at least one of the drive frequency and the duty ratio of the pulse generating circuit 82 to appropriately adjust the magnetic flux generated by the secondary coil L2. Specifically, the secondary control circuit 385 performs feedback control by comparing the detected current value with the target current value Itg at a predetermined drive frequency that is stored in advance, so that the detected current value approaches the target current value Itg.

[0080] According to the third embodiment described above, the same effects as those of the above-mentioned embodiments are achieved. Furthermore, when the detection value is outside a predetermined range, that is, when the detection value is larger than the first threshold value Ith1 and smaller than the second threshold value Ith2, the secondary-side control circuit 385 outputs an abnormality signal to the power-receiving-side control unit 96. This allows the power-receiving-side control unit 96 to which the abnormality signal is input to execute processing to deal with the abnormality.

[0081] D. Fourth embodiment: The secondary side control circuit 85 of this embodiment differs from the first embodiment in that it performs the abnormality detection process shown in Figures 15 and 16. The same configurations and processing steps as those of the above embodiments are given the same reference numerals, and detailed explanations are omitted as appropriate. The secondary side control circuit 85 repeatedly performs the abnormality detection process when the power receiving device 80 is in a non-power receiving state. The secondary side voltage sensor M2 detects the voltage value supplied to the pulse generating circuit 82 in the non-power receiving state, and detects the voltage value output from the pulse generating circuit 82 in the power receiving state.

[0082] In step S1, the secondary side control circuit 85 detects the detection target 14. In step S100, the secondary side control circuit 85 sets the number of cycles Nm and the cumulative number of cycles Nt, which are variables used in this processing routine, to initial values ​​of zero. The number of cycles Nm is a variable for counting the number of second cycles T2 shown in FIG. 5, which are cycles of supply drive and pause drive in burst drive. The cumulative number of cycles Nt is a variable used to detect the occurrence of chattering. Note that in this embodiment, step S2 performed in the first embodiment is omitted.

[0083] In step S102, the secondary control circuit 85 increments the number of cycles Nm. In step S3, the secondary control circuit 85 generates a magnetic flux in the secondary coil L2 as a magnetic flux generating coil during the drive period Td. In step S104, the secondary control circuit 85 starts pause drive of the pulse generating circuit 82. The secondary control circuit 85 measures the elapsed time from the start of pause drive using a built-in timer circuit. When the power transmitting device 10 transitions to a power transmitting state during the pause period Tp, the secondary control circuit 85 executes the switching process shown in FIG. 4, so that the power receiving device 80 transitions to a power receiving state. In the power receiving state, the secondary control circuit 85 rectifies and drives the pulse generating circuit 82 to function as a rectifier. As a result, when no abnormality occurs, the detection voltage Vd of the secondary voltage sensor M2 becomes the target voltage.

[0084] In step S106, the secondary-side control circuit 85 determines whether the detection voltage Vd of the secondary-side voltage sensor M2 is greater than a predetermined reference voltage Vthd. In this embodiment, the determination of whether power supply by the power transmitting device 10 has started is performed in step S106. The reference voltage Vthd is smaller than the target voltage of the output voltage of the pulse generating circuit 82 when the power receiving device 80 is receiving power. Therefore, when the detection voltage Vd is greater than the reference voltage Vthd, it can be determined that the power receiving device 80 has transitioned from a non-power receiving state to a power receiving state.

[0085] As another method for determining whether or not the power transmission device 10 has started power supply, the secondary-side control circuit 85 may determine whether or not the drive method of the pulse generating circuit 82 has been switched from pause drive to rectification drive, that is, whether or not a switching process has been performed. In this case, the secondary-side control circuit 85 determines that the power transmission device 10 has started power supply when the switching process has been performed.

[0086] If it is determined in step S106 that the detected voltage Vd is not greater than the reference voltage Vth, that is, that the detected voltage Vd is equal to or less than the reference voltage Vth, the secondary-side control circuit 85 determines in step S108 whether or not the pause period Tp has elapsed by referring to the measurement time of the time-elapse circuit. If it is determined in step S108 that the pause period Tp has not elapsed, the secondary-side control circuit 85 returns the process to step S106 after a predetermined time has elapsed, since power supply from the power transmitting device 10 has not yet started. The predetermined time is, for example, several μs.

[0087] If it is determined in step S108 that the pause period Tp has elapsed, the secondary-side control circuit 85 determines in step S110 as a first determination process whether the cycle count Nm is equal to or greater than a predetermined reference cycle count Nth1. In step S108, it is determined that the pause period Tp has elapsed when power supply from the power transmitting device 10 has not started during the pause period Tp. The reference cycle count Nth1 is an integer equal to or greater than 2, and is "2" in this embodiment. If it is determined in step S110 that the cycle count Nm is not equal to or greater than the reference cycle count Nth1, that is, the cycle count Nm is smaller than the reference cycle count Nth1, the secondary-side control circuit 85 returns the process to step S102 after a predetermined time has elapsed. The predetermined time is, for example, several μs. The reason for returning the process to step S102 is to perform the supply drive and pause drive of the next cycle.

[0088] If it is determined in step S110 that the number of cycles Nm is equal to or greater than the reference number of cycles Nth1, it is determined that the power transmitting device 10 is broken, and the secondary-side control circuit 85 advances the process to step S32. Step S32 is performed because the number of cycles Nm during which the power transmitting device 10 did not transition to a power transmitting state despite the generation of magnetic flux in the secondary-side coil L2 in step S3 is equal to or greater than the reference number of cycles Nth1. In step S32, the secondary-side control circuit 85 performs output processing to output an abnormality signal notifying the power receiving-side control unit 96 of the abnormality. This allows a passenger in the vehicle VE to know that there is an abnormality in charging. After performing step S32, the secondary-side control circuit 85 ends this processing routine.

[0089] As another embodiment, the secondary-side control circuit 85 may perform a stop process for setting the pulse generating circuit 82 to a stopped state instead of the process content of step S32. The secondary-side control circuit 85 may perform both the output process and the stop process. Here, the stopped state of the pulse generating circuit 82 is a state in which an off signal is input to each of the switching elements Q1 to Q4 of the pulse generating circuit 82. The stop process is a process in which the secondary-side control circuit 85 outputs an off signal to each of the switching elements Q1 to Q4. The stop process by the secondary-side control circuit 85 can suppress power consumption of the battery 84. The same applies to step S118 described later.

[0090] If it is determined in step S106 that the detected voltage Vd is greater than the reference voltage Vth, the secondary-side control circuit 85 counts the cumulative number of times Nt that the detected voltage Vd has changed from within the power receiving range to outside the power receiving range during a predetermined detection period in step S112 of Fig. 16. The detection period is, for example, several hundred µs. Within the power receiving range means a range greater than the reference voltage Vthd. Outside the power receiving range means a range equal to or less than the reference voltage Vthd.

[0091] In step S114 as the second judgment process, the secondary side control circuit 85 judges whether the cumulative number Nt is equal to or greater than the reference cumulative number Nth2. The reference cumulative number Nth2 is an integer equal to or greater than 1, and is set to "1" in this embodiment. If it is judged in step S114 that the cumulative number Nt is equal to or greater than the reference cumulative number Nth2, it is judged that chattering has occurred due to a failure of the power transmitting device 10, and therefore, in step S118, the secondary side control circuit 85 performs an output process of outputting an abnormality signal notifying an abnormality to the power receiving side control unit 96, similar to step S32, and ends this processing routine. On the other hand, if it is judged in step S114 that the cumulative number Nt is not equal to or greater than the reference cumulative number Nth2, step S118 is skipped and this processing routine is ended.

[0092] According to the fourth embodiment described above, if it is determined in step S110 that the number of cycles Nm is equal to or greater than the reference number of cycles Nth1, the secondary-side control circuit 85 performs output processing to output an abnormality signal in step S32. This allows a passenger in the vehicle VE to know that an abnormality has occurred when the power transmitting device 10 has a malfunction. Also, if it is determined in step S114 that the cumulative number Nt is equal to or greater than the reference cumulative number, output processing is performed in step S118. This allows a passenger in the vehicle VE to know that an abnormality has occurred in the power supply when the power receiving device 80 is not receiving power well due to chattering.

[0093] E. Other embodiments: (E1) Fifth embodiment: 17 includes an immittance filter 88 in addition to the circuit configuration of the first embodiment. The immittance filter 88 is a T-LCL type immittance filter including a pair of coils L41, L42 and a capacitor C41. In this case, the secondary voltage sensor M2 may be attached at a position where the voltage of the capacitor C41 can be detected.

[0094] (E2) Sixth embodiment: 18, the coil L41 of the immittance filter 88 of the fifth embodiment is omitted. Even if the coil L41 is omitted, the immittance filter 88 can be configured by substituting the leakage inductance of the secondary coil L2 as the coil L41.

[0095] (E3) Seventh embodiment: The power receiving device 680 of the seventh embodiment shown in FIG. 19 is different from the first embodiment in that it includes a magnetic flux generating coil L61 in addition to the secondary coil L2 and a rectifier circuit 89 in addition to the pulse generating circuit 82. The rectifier circuit 89 is realized by a diode bridge. The magnetic flux generating coil L61 is attached to the secondary coil L2 at a position where it can be magnetically coupled to the primary coil L1. The pulse generating circuit 82 receives DC power from a battery 84. Even in the configuration including the pulse generating circuit 82 in addition to the rectifier circuit 89, the magnetic flux generated in the primary coil L1 can be appropriately controlled by adjusting the drive frequency and duty ratio of the pulse generating circuit 82.

[0096] (E4) In the above first embodiment, the power supplied to the secondary coil L2 serving as a magnetic flux generating coil is adjusted by adjusting the drive frequency and duty ratio of the pulse generating circuit 82. As another embodiment, a DC / DC converter may be provided between the pulse generating circuit 82 and the battery 84, and the power supplied to the magnetic flux generating coil may be adjusted by changing the voltage value supplied to the pulse generating circuit 82 using the DC / DC converter.

[0097] (E5) In the third embodiment, the pulse generating circuit 82 is driven so as to eliminate the deviation of the current value flowing through the secondary coil L2 from the target current value Itg caused by resonance offset, using the detection value of the current sensor M3. In this case, instead of the current sensor M3, a voltage sensor that detects the voltage of the secondary coil L2 or a voltage sensor that detects the voltage of the secondary capacitor C2 may be provided. Then, the secondary control circuit 385 may adjust the drive frequency and duty ratio of the pulse generating circuit 82 using the detection value of this voltage sensor instead of the detection value of the current sensor M3.

[0098] (E6) In the first embodiment, the primary side resonant circuit 12 has a primary side capacitor C1 connected in series to the primary side coil L1, and the secondary side resonant circuit 81 has a secondary side capacitor C2 connected in series to the secondary side coil L2, which is a so-called SS type circuit configuration. The circuit configuration of the primary side resonant circuit 12 and the circuit configuration of the secondary side resonant circuit 81 are not limited to the SS type. (a) For example, the primary side resonant circuit 12 may have a so-called PS type circuit configuration in which the primary side capacitor C1 is connected in parallel to the primary side coil L1, and the secondary side resonant circuit 81 may have a secondary side capacitor C2 connected in series to the secondary side coil L2. (b) Also, in addition to the primary side capacitor C1 connected in series to the primary side coil L1, a capacitor connected in parallel to the primary side coil L1 is provided, and the secondary side resonant circuit 81 may have a so-called P-SS type circuit configuration in which two secondary side capacitors C2 are connected in series to each of both terminals of the secondary side coil L2. (c) The primary resonant circuit 12 may also include a closed circuit in which a coil and a capacitor are connected in series. The coil of this closed circuit is arranged at a position where it can be magnetically coupled to the secondary coil L2 when the primary coil L1 and secondary coil L2 are magnetically coupled. (d) The capacitor of the closed circuit may also be connected in parallel to the coil, not in series. (e) The primary resonant circuit 12 may also include a coil connected in series to the primary coil L1, and a capacitor connected in parallel to the coil. The coil is arranged at a position where it can be magnetically coupled to the secondary coil L2 when the primary coil L1 and secondary coil L2 are magnetically coupled.

[0099] (E7) In the first embodiment, the switching elements Q1 to Q4 constituting the pulse generating circuit 82 are realized by MOSFETs. In another embodiment, the switching elements Q1 to Q4 may be realized by other semiconductor elements, for example, IGBTs (Insulated Gate Bipolar Transistors) connected to freewheeling diodes.

[0100] (E8) In the first embodiment, the power receiving side control unit 96 outputs a power supply permission signal or a power supply prohibition signal. When the power supply prohibition signal is input, the secondary side control circuit 85 does not drive the pulse generating circuit 82. In addition to this form, there is also a form in which the power receiving side control unit 96 outputs neither the power supply permission signal nor the power supply prohibition signal. In this case, when the power supply permission signal is not input, the secondary side control circuit 85 may be configured not to drive the pulse generating circuit 82 when the power supply prohibition signal is input. This makes it possible to avoid power supply when the battery 84 is not suitable for charging.

[0101] (E9) In the first embodiment, in the non-power receiving state, no current flows through the secondary coil L2 of the power receiving device 80. As another embodiment, in the non-power receiving state, a current may be passed through the secondary coil L2 of the power receiving device 80, and in step S3, the secondary control circuit 85 may increase the current passed through the secondary coil L2 to increase the magnetic flux radiated to the linkage with the primary coil L1.

[0102] The present disclosure is not limited to the above-mentioned embodiments and modifications, and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features in the embodiments and modifications corresponding to the technical features in each aspect described in the Summary of the Invention column can be appropriately replaced or combined 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 appropriately deleted.

[0103] Other forms: The features of the present disclosure are as follows: (Form 1) A contactless power supply system (1, 201, 301) that wirelessly supplies power from a power transmitting device (10, 210, 310) to a power receiving device (80, 280, 380), The power transmitting device is a primary side resonant circuit (12) having a primary side coil (L1) and a primary side capacitor (C1); an AC power source (11) that applies AC power having a predetermined operating frequency to the primary side resonant circuit; a primary side detection circuit (120) for detecting the magnitude of the magnetic flux interlinked with the primary side coil or the magnitude of the magnetic flux in the vicinity of the primary side coil; The power receiving device is a secondary-side resonant circuit (81) having a secondary-side coil (L2) for magnetically coupling with the primary-side coil and a secondary-side capacitor (C2); a magnetic flux generating circuit (86, 286, 386) including a magnetic flux generating coil (L2) for generating a magnetic flux to be radiated to the primary coil in a standby state of the power transmitting device, a pulse generating circuit (82) for supplying AC power to the magnetic flux generating coil, and a secondary control circuit (85, 285, 385) for controlling the pulse generating circuit; A secondary detection circuit (M2, 281, M3) that detects at least one of a voltage value supplied to the pulse generating circuit, a current value flowing through the secondary coil or the pulse generating circuit, and a magnitude of a magnetic flux generated from the primary coil; when the primary side detection circuit detects an increase in magnetic flux linking with the primary side coil or in the vicinity of the primary side coil, the power transmitting device transitions from the standby state to a power transmitting state in which a power transmitting current is passed through the primary side coil; The magnetic flux generating circuit adjusts the generated magnetic flux using the detection value of the secondary side detection circuit. (Form 2) The wireless power supply system according to aspect 1, The power receiving device further comprises: A battery (84) is provided to supply DC power to the pulse generating circuit; The secondary side detection circuit is a voltage detection circuit that detects an output voltage value of the battery as a voltage value supplied to the pulse generation circuit. (Form 3) The wireless power supply system according to aspect 2, The pulse generating circuit is configured as an inverter, The secondary side control circuit adjusts at least one of a drive frequency and a duty ratio of the pulse generating circuit to adjust a generated magnetic flux. (Form 4) The wireless power supply system according to aspect 2 or 3, The secondary side control circuit stops the supply of AC power by the pulse generating circuit when the detection value is outside a predetermined range. (Form 5) The wireless power supply system according to any one of aspects 2 to 3, the secondary-side control circuit, in a non-power-receiving state, periodically repeats a supply drive that causes the pulse generation circuit to supply AC power to the magnetic flux generating coil and a pause drive that causes the pulse generation circuit to pause the supply of AC power to the magnetic flux generating coil; The power transmitting device is a contactless power supply system in which, after the primary side detection circuit detects an increase in magnetic flux linking with the primary side coil or in the vicinity of the primary side coil, the system transitions to the power transmission state after a predetermined waiting time for transitioning to the power transmission state during the pause driving period has elapsed. (Form 6) The wireless power supply system according to any one of aspects 1 to 5, The secondary side detection circuit is a magnetic flux detection circuit that detects the magnitude of the magnetic flux generated in the primary side coil. (Form 7) 7. The wireless power supply system according to claim 6, the pulse generating circuit is configured as an inverter; The secondary side control circuit adjusts at least one of a drive frequency and a duty ratio of the pulse generating circuit to adjust a generated magnetic flux. (Form 8) The wireless power supply system according to aspect 6 or 7, The secondary side control circuit stops the supply of AC current by the pulse generating circuit when the detection value is outside a predetermined range. (Form 9) The wireless power supply system according to any one of aspects 6 to 8, The secondary side control circuit includes: a supply drive for supplying AC power from the pulse generating circuit to the magnetic flux generating coil and a pause drive for causing the pulse generating circuit to pause the supply of AC power to the magnetic flux generating coil are periodically repeated; and if the detection value is within a predetermined magnetic flux range after the supply drive is performed, the pause drive is continued for a predetermined time or longer. (Form 10) The wireless power supply system according to any one of aspects 6 to 9, The secondary side control circuit includes: A contactless power supply system that performs control so as to maximize power supply efficiency using a coupling coefficient calculated using the detection value. (Form 11) The wireless power supply system according to any one of aspects 1 to 10, The secondary side detection circuit is a current detection circuit that detects a current value flowing through the secondary side coil or the pulse generating circuit. (Form 12) 12. The wireless power supply system according to claim 11, the pulse generating circuit is configured as an inverter; The secondary side control circuit includes: A contactless power supply system that adjusts a generated magnetic flux by adjusting at least one of a drive frequency and a duty ratio of the pulse generating circuit using the detection value when the pulse generating circuit is driven under predetermined conditions. (Form 13) 13. The wireless power supply system according to claim 11, The secondary side control circuit includes: The non-contact power supply system outputs an abnormality signal when the detected value is outside a predetermined range. (Form 14) The wireless power supply system according to any one of aspects 1 to 13, The secondary side control circuit includes: A contactless power supply system, comprising: a power supply inhibiting signal receiving means for inhibiting a power supply from being transmitted to the power supply control means; a power supply enabling signal receiving means for inhibiting a power supply from being transmitted to the power supply control means; (Form 15) 15. The wireless power supply system according to claim 14, The secondary side control circuit includes: the contactless power supply system starts driving the pulse generating circuit when the power supply permission signal is received after the power supply prohibition signal is received. (Form 16) The wireless power supply system according to aspect 5, The power receiving device is mounted on a moving object (VE), The secondary side control circuit includes: The non-contact power supply system adjusts the period of the pause drive by using the moving speed acquired by a speed acquisition unit (97) that acquires the moving speed of the moving body. (Form 17) The wireless power supply system according to aspect 1, The power receiving device further includes a battery (84) that supplies DC power to the pulse generating circuit, the pulse generating circuit functions as an inverter that converts DC power supplied from the battery into AC power in a non-powered state, and functions as a rectifier that converts AC power output from the secondary resonant circuit into DC power in a power-receiving state; the secondary-side control circuit, in the non-power-receiving state, periodically repeats a supply drive that causes the pulse generation circuit to supply AC power to the magnetic flux generating coil for a predetermined drive period, and a pause drive that pauses the supply of AC power from the pulse generation circuit to the magnetic flux generating coil for a predetermined pause period after the supply drive; The secondary side control circuit includes: a switching process for switching from the pause drive to a rectification drive that causes the pulse generating circuit to function as the rectifier when power supply from the power transmitting device is started during the pause period; performing a first determination process for determining whether or not a number of cycles of the supply drive and the pause drive is equal to or greater than a predetermined reference number of cycles when the power transmission device has not started to supply power during the pause period after the pause period ends; When it is determined in the first determination process that the number of cycles is equal to or greater than the reference number of cycles, at least one of an output process that outputs an abnormality signal and a stop process that sets the pulse generating circuit to a stopped state is performed. (Form 18) The wireless power supply system according to aspect 1, The power receiving device further includes a battery (84) that supplies DC power to the pulse generating circuit, the secondary-side detection circuit, which detects a voltage value supplied to the pulse generating circuit, detects both a voltage value supplied to the pulse generating circuit and a voltage value output from the pulse generating circuit; the pulse generating circuit functions as an inverter that converts DC power supplied from the battery into AC power in a non-powered state, and functions as a rectifier that converts AC power output from the secondary resonant circuit into DC power in a power-receiving state; the secondary-side control circuit, in the non-power-receiving state, periodically repeats a supply drive that causes the pulse generation circuit to supply AC power to the magnetic flux generating coil for a predetermined drive period, and a pause drive that pauses the supply of AC power from the pulse generation circuit to the magnetic flux generating coil for a predetermined pause period after the supply drive; The secondary side control circuit includes: a switching process for switching from the pause drive to a rectification drive that causes the pulse generating circuit to function as the rectifier when power supply from the power transmitting device is started during the pause period; performing a second determination process for determining whether or not a cumulative number of times that the detection value changes from within a predetermined power receiving range to outside the power receiving range within a predetermined detection period is equal to or greater than a predetermined reference cumulative number of times while the rectification drive is being performed; when it is determined in the second determination process that the accumulated number is equal to or greater than the reference accumulated number, at least one of an output process of outputting an abnormality signal and a stop process of setting the pulse generating circuit to a stopped state is performed. (Form 19) The wireless power supply system according to aspect 1, The secondary coil is used as the magnetic flux generating coil, The power receiving device further includes a battery (84) that supplies DC power to the pulse generating circuit, the pulse generating circuit is a synchronous rectifier circuit, which functions as an inverter that converts DC power supplied from the battery into AC power in a non-powered state, and functions as a rectifier that converts AC power output from the secondary resonant circuit into DC power in a power-receiving state; The battery supplies DC power to the pulse generating circuit in the non-power-receiving state, and stores the DC power output from the secondary-side resonant circuit in the power-receiving state. (Form 20) A power receiving device (80, 280, 380) that receives power from a power transmitting device (10, 210, 310) in a wireless manner, The power transmitting device is a primary side resonant circuit (12) having a primary side coil (L1) and a primary side capacitor (C1); an AC power source (11) that applies AC power having a predetermined operating frequency to the primary side resonant circuit; a primary side detection circuit (120) for detecting the magnitude of the magnetic flux interlinked with the primary side coil or the magnitude of the magnetic flux in the vicinity of the primary side coil; The power receiving device is a secondary-side resonant circuit (81) having a secondary-side coil (L2) for magnetically coupling with the primary-side coil and a secondary-side capacitor (C2); a magnetic flux generating circuit (86, 286, 386) including a magnetic flux generating coil (L2) for generating a magnetic flux to be radiated to the primary coil in a standby state of the power transmitting device, a pulse generating circuit (82) for supplying AC power to the magnetic flux generating coil, and a secondary control circuit (85, 285, 385) for controlling the pulse generating circuit; A secondary detection circuit (M2, 281, M3) that detects at least one of a voltage value supplied to the pulse generating circuit, a current value flowing through the secondary coil or the pulse generating circuit, and a magnitude of a magnetic flux generated from the primary coil; when the primary side detection circuit detects an increase in magnetic flux linking with the primary side coil or in the vicinity of the primary side coil, the power transmitting device transitions from the standby state to a power transmitting state in which a power transmitting current is passed through the primary side coil; The magnetic flux generating circuit adjusts the generated magnetic flux using the detection value of the secondary side detection circuit. (Form 21) A power transmitting device (10, 210, 310) that wirelessly supplies power to a power receiving device (80, 280, 380), The power transmitting device is a primary side resonant circuit (12) having a primary side coil (L1) and a primary side capacitor (C1); an AC power source (11) that applies AC power having a predetermined operating frequency to the primary side resonant circuit; a primary side detection circuit (120) for detecting the magnitude of the magnetic flux interlinked with the primary side coil or the magnitude of the magnetic flux in the vicinity of the primary side coil; The power receiving device is a secondary-side resonant circuit (81) having a secondary-side coil (L2) for magnetically coupling with the primary-side coil and a secondary-side capacitor (C2); a magnetic flux generating circuit (86, 286, 386) including a magnetic flux generating coil (L2) for generating a magnetic flux to be radiated to the primary coil in a standby state of the power transmitting device, a pulse generating circuit (82) for supplying AC power to the magnetic flux generating coil, and a secondary control circuit (85, 285, 385) for controlling the pulse generating circuit; A secondary detection circuit (M2, 281, M3) that detects at least one of a voltage value supplied to the pulse generating circuit, a current value flowing through the secondary coil or the pulse generating circuit, and a magnitude of a magnetic flux generated from the primary coil; the magnetic flux generating circuit adjusts the generated magnetic flux using the detection value of the secondary side detection circuit; When the primary side detection circuit detects an increase in magnetic flux linking to the primary side coil or in the vicinity of the primary side coil, the power transmission device transitions from the standby state to a power transmission state in which a transmission current flows through the primary side coil. [Explanation of symbols]

[0104] 1... non-contact power supply system, 10... power transmission device, 11... AC power source, 12... primary side resonant circuit, 13... primary side control circuit, 80... power receiving device, 81... secondary side resonant circuit, 82... pulse generating circuit, 84... battery, 85... secondary side control circuit, 86... magnetic flux generating circuit, 120... primary side detection circuit, C1... primary side capacitor, C2... secondary side capacitor, L1... primary side coil, L2... secondary side coil, M1... primary side voltage sensor, M2... secondary side voltage sensor, M3... current sensor

Claims

1. A contactless power supply system (1, 201, 301) that supplies power from a power transmitting device (10, 210, 310) to a power receiving device (80, 280, 380) in a contactless manner, The power transmitting device is A primary resonant circuit (12) having a primary coil (L1) and a primary capacitor (C1); an AC power source (11) that applies AC power having a predetermined operating frequency to the primary side resonant circuit; A primary detection circuit (120) for detecting the magnitude of the magnetic flux interlinked with the primary coil or the magnitude of the magnetic flux in the vicinity of the primary coil, The power receiving device is a secondary-side resonant circuit (81) having a secondary-side coil (L2) for magnetically coupling with the primary-side coil and a secondary-side capacitor (C2); a magnetic flux generating circuit (86, 286, 386) including a magnetic flux generating coil (L2) for generating a magnetic flux to be radiated to the primary coil in a standby state of the power transmitting device, a pulse generating circuit (82) for supplying AC power to the magnetic flux generating coil, and a secondary control circuit (85, 285, 385) for controlling the pulse generating circuit; A secondary detection circuit (M2, 281, M3) that detects at least one of a voltage value supplied to the pulse generating circuit, a current value flowing through the secondary coil or the pulse generating circuit, and a magnitude of a magnetic flux generated from the primary coil, when the primary side detection circuit detects an increase in magnetic flux linking with the primary side coil or in the vicinity of the primary side coil, the power transmitting device transitions from the standby state to a power transmitting state in which a power transmitting current is passed through the primary side coil; The magnetic flux generating circuit adjusts the magnitude of the generated magnetic flux using the detection value of the secondary detection circuit when generating magnetic flux to be radiated to the primary coil.

2. The non-contact power supply system according to claim 1, The power receiving device further comprises: A battery (84) is provided to supply DC power to the pulse generating circuit; The secondary side detection circuit is a voltage detection circuit that detects an output voltage value of the battery as a voltage value supplied to the pulse generation circuit.

3. The non-contact power supply system according to claim 2, The pulse generating circuit is configured as an inverter, The secondary-side control circuit adjusts at least one of a drive frequency and a duty ratio of the pulse generating circuit to adjust a generated magnetic flux.

4. The contactless power supply system according to claim 2 or 3, The secondary side control circuit stops the supply of AC power by the pulse generating circuit when the detection value is outside a predetermined range.

5. The non-contact power supply system according to claim 3, the secondary-side control circuit, in a non-power-receiving state, periodically repeats a supply drive that causes the pulse generation circuit to supply AC power to the magnetic flux generating coil and a pause drive that causes the pulse generation circuit to pause the supply of AC power to the magnetic flux generating coil; The power transmitting device is a contactless power supply system in which, after the primary side detection circuit detects an increase in magnetic flux linking with the primary side coil or in the vicinity of the primary side coil, the system transitions to the power transmission state after a predetermined waiting time for transitioning to the power transmission state during the pause driving period has elapsed.

6. The non-contact power supply system according to claim 1, The secondary side detection circuit is a magnetic flux detection circuit that detects the magnitude of a magnetic flux generated in the primary side coil.

7. The non-contact power supply system according to claim 6, the pulse generating circuit is configured as an inverter; The secondary-side control circuit adjusts at least one of a drive frequency and a duty ratio of the pulse generating circuit to adjust a generated magnetic flux.

8. The contactless power supply system according to claim 6 or 7, The secondary side control circuit stops the supply of AC current by the pulse generating circuit when the detection value is outside a predetermined range.

9. The non-contact power supply system according to claim 7, The secondary side control circuit includes: a supply drive for supplying AC power from the pulse generating circuit to the magnetic flux generating coil and a pause drive for causing the pulse generating circuit to pause the supply of AC power to the magnetic flux generating coil are periodically repeated; and if the detection value is within a predetermined magnetic flux range after the supply drive is performed, the pause drive is continued for a predetermined time or longer.

10. The non-contact power supply system according to claim 6, The secondary side control circuit includes: A contactless power supply system that performs control so as to maximize power supply efficiency using a coupling coefficient calculated using the detection value.

11. The non-contact power supply system according to claim 1, The secondary side detection circuit is a current detection circuit that detects a value of a current flowing through the secondary side coil or the pulse generating circuit.

12. The non-contact power supply system according to claim 11, the pulse generating circuit is configured as an inverter; The secondary side control circuit includes: A contactless power supply system that adjusts a generated magnetic flux by adjusting at least one of a drive frequency and a duty ratio of the pulse generating circuit using the detection value when the pulse generating circuit is driven under predetermined conditions.

13. The contactless power supply system according to claim 11 or 12, The secondary side control circuit includes: The non-contact power supply system outputs an abnormality signal when the detected value is outside a predetermined range.

14. The non-contact power supply system according to claim 1, The secondary side control circuit includes: A contactless power supply system, comprising: a power supply inhibiting signal receiving means for inhibiting a power supply from being transmitted to the power supply control means; a power supply enabling signal receiving means for inhibiting a power supply from being transmitted to the power supply control means;

15. The contactless power supply system according to claim 14, The secondary side control circuit includes: the contactless power supply system starts driving the pulse generating circuit when the power supply permission signal is received after the power supply prohibition signal is received.

16. The non-contact power supply system according to claim 5, The power receiving device is mounted on a mobile object (VE), The secondary side control circuit includes: A contactless power supply system, comprising: a speed acquisition unit (97) that acquires a moving speed of the moving body; and a period of the pause drive that is adjusted using the moving speed acquired by the speed acquisition unit (97).

17. The non-contact power supply system according to claim 1, The power receiving device further includes a battery (84) that supplies DC power to the pulse generating circuit, the pulse generating circuit functions as an inverter that converts DC power supplied from the battery into AC power in a non-powered state, and functions as a rectifier that converts AC power output from the secondary resonant circuit into DC power in a power-receiving state; the secondary-side control circuit, in the non-power-receiving state, periodically repeats a supply drive that causes the pulse generation circuit to supply AC power to the magnetic flux generating coil for a predetermined drive period, and a pause drive that pauses the supply of AC power from the pulse generation circuit to the magnetic flux generating coil for a predetermined pause period after the supply drive; The secondary side control circuit includes: a switching process for switching from the pause drive to a rectification drive that causes the pulse generating circuit to function as the rectifier when power supply from the power transmitting device is started during the pause period; a first determination process for determining whether or not a number of cycles of the supply drive and the pause drive is equal to or greater than a predetermined reference number of cycles when the power transmission device does not start supplying power during the pause period after the pause period ends; a contactless power supply system that, when it is determined in the first judgment process that the number of cycles is equal to or greater than the reference number of cycles, performs at least one of an output process that outputs an abnormality signal and a stop process that sets the pulse generating circuit to a stopped state.

18. The non-contact power supply system according to claim 1, The power receiving device further includes a battery (84) that supplies DC power to the pulse generating circuit, the secondary-side detection circuit detects both a voltage value supplied to the pulse generating circuit and a voltage value output from the pulse generating circuit; the pulse generating circuit functions as an inverter that converts DC power supplied from the battery into AC power in a non-powered state, and functions as a rectifier that converts AC power output from the secondary resonant circuit into DC power in a power-receiving state; the secondary-side control circuit, in the non-power-receiving state, periodically repeats a supply drive that causes the pulse generation circuit to supply AC power to the magnetic flux generating coil for a predetermined drive period, and a pause drive that pauses the supply of AC power from the pulse generation circuit to the magnetic flux generating coil for a predetermined pause period after the supply drive; The secondary side control circuit includes: a switching process for switching from the pause drive to a rectification drive that causes the pulse generating circuit to function as the rectifier when power supply from the power transmitting device is started during the pause period; a second determination process for determining whether or not a cumulative number of times that the detection value changes from within a predetermined power receiving range to outside the power receiving range within a predetermined detection period is equal to or greater than a predetermined reference cumulative number of times while the rectification drive is being performed; when it is determined in the second determination process that the accumulated number is equal to or greater than the reference accumulated number, at least one of an output process of outputting an abnormality signal and a stop process of setting the pulse generating circuit to a stopped state is performed.

19. The non-contact power supply system according to claim 1, The secondary coil is used as the magnetic flux generating coil, The power receiving device further includes a battery (84) that supplies DC power to the pulse generating circuit, the pulse generating circuit is a synchronous rectifier circuit, which functions as an inverter that converts DC power supplied from the battery into AC power in a non-powered state, and functions as a rectifier that converts AC power output from the secondary resonant circuit into DC power in a power-receiving state; The battery supplies DC power to the pulse generating circuit in the non-power-receiving state, and stores the DC power output from the secondary-side resonant circuit in the power-receiving state.

20. A power receiving device (80, 280, 380) that receives power contactlessly from a power transmitting device (10, 210, 310), The power transmitting device is A primary resonant circuit (12) having a primary coil (L1) and a primary capacitor (C1); an AC power source (11) that applies AC power having a predetermined operating frequency to the primary side resonant circuit; A primary detection circuit (120) for detecting the magnitude of the magnetic flux interlinked with the primary coil or the magnitude of the magnetic flux in the vicinity of the primary coil, The power receiving device is a secondary-side resonant circuit (81) having a secondary-side coil (L2) for magnetically coupling with the primary-side coil and a secondary-side capacitor (C2); a magnetic flux generating circuit (86, 286, 386) including a magnetic flux generating coil (L2) for generating a magnetic flux to be radiated to the primary coil in a standby state of the power transmitting device, a pulse generating circuit (82) for supplying AC power to the magnetic flux generating coil, and a secondary control circuit (85, 285, 385) for controlling the pulse generating circuit; A secondary detection circuit (M2, 281, M3) that detects at least one of a voltage value supplied to the pulse generating circuit, a current value flowing through the secondary coil or the pulse generating circuit, and a magnitude of a magnetic flux generated from the primary coil, when the primary side detection circuit detects an increase in magnetic flux linking with the primary side coil or in the vicinity of the primary side coil, the power transmitting device transitions from the standby state to a power transmitting state in which a power transmitting current is passed through the primary side coil; The magnetic flux generating circuit adjusts the magnitude of the generated magnetic flux using the detection value of the secondary detection circuit when generating magnetic flux to be radiated to the primary coil.

21. A power transmitting device (10, 210, 310) that wirelessly supplies power to a power receiving device (80, 280, 380), The power transmitting device is A primary resonant circuit (12) having a primary coil (L1) and a primary capacitor (C1); an AC power source (11) that applies AC power having a predetermined operating frequency to the primary side resonant circuit; A primary detection circuit (120) for detecting the magnitude of the magnetic flux interlinked with the primary coil or the magnitude of the magnetic flux in the vicinity of the primary coil, The power receiving device is a secondary-side resonant circuit (81) having a secondary-side coil (L2) for magnetically coupling with the primary-side coil and a secondary-side capacitor (C2); a magnetic flux generating circuit (86, 286, 386) including a magnetic flux generating coil (L2) for generating a magnetic flux to be radiated to the primary coil in a standby state of the power transmitting device, a pulse generating circuit (82) for supplying AC power to the magnetic flux generating coil, and a secondary control circuit (85, 285, 385) for controlling the pulse generating circuit; A secondary detection circuit (M2, 281, M3) that detects at least one of a voltage value supplied to the pulse generating circuit, a current value flowing through the secondary coil or the pulse generating circuit, and a magnitude of a magnetic flux generated from the primary coil, the magnetic flux generating circuit adjusts the magnitude of the magnetic flux to be generated by using a detection value of the secondary detection circuit when generating magnetic flux to be radiated to the primary coil; The power transmission device transitions from the standby state to a power transmission state in which a transmission current flows through the primary coil when the primary side detection circuit detects an increase in magnetic flux linking with the primary side coil or in the vicinity of the primary side coil.

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