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

Abstract

A non-contact power supply system (1) is provided with a power transmission device (10) and a power reception device (80) that supplies power from the power transmission device in a non-contact manner. A power receiving device is provided with: a secondary-side resonance circuit (81); a magnetic flux generation circuit (86) having: a magnetic flux generation coil (L2) for generating magnetic flux radiated to the primary-side coil (L1); 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 one of the value of the voltage supplied to the pulse generation circuit, the value of the current flowing through the secondary-side coil, and the magnitude of the magnetic flux generated from the primary-side coil. The magnetic flux generation circuit shifts from a standby state to a power transmission state in which a power transmission current flows through the primary-side coil, and adjusts the generated magnetic flux using a detection value of the secondary-side detection circuit.

Description

Citation of Related Applications

[0001] This application is based on Japanese Patent Application No. 2022-199166 filed on December 14, 2022, the contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to a non-contact power supply device, a power receiving device, and a power transmission device. Background Art

[0003] Various techniques for non-contact power supply from a power transmission side to a power receiving side by electromagnetic induction have been proposed (for example, Patent Document 1). In the technique of Patent Document 1, using two-way wireless communication, the charging device on the power transmission side receives the measurement result of the electromagnetic field strength transmitted from the device on the power receiving side, and then starts power transmission after the charging device moves to the optimal position. Prior Art Documents Patent Documents

[0004] Patent Document 1: Japanese Patent Laid-Open No. 2010-88178 Summary of the Invention

[0005] However, when there is a time delay in the transmission during two-way wireless communication before the start of power transmission, the start of power transmission may be delayed.

[0006] The present disclosure can be implemented in the following manner.

[0007] According to a first aspect of the present disclosure, a non-contact power supply system for supplying power from a power transmission device to a power reception device in a non-contact manner is provided. The power transmission device includes: a primary-side resonant circuit having a primary-side coil and a primary-side capacitor; an AC power supply for applying AC power of a predetermined operating frequency to the primary-side resonant circuit; and a primary-side detection circuit for detecting the magnitude of the magnetic flux linked to the primary-side coil or the magnitude of the magnetic flux near the primary-side coil. The power reception device includes: a secondary-side resonant circuit having a secondary-side coil for magnetic coupling with the primary-side coil and a secondary-side capacitor; a magnetic flux generation circuit having: a magnetic flux generation coil for generating a magnetic flux radiated to the primary-side coil in a standby state of the power transmission device; a pulse generation circuit for supplying AC power to the magnetic flux generation coil; and a secondary-side control circuit for controlling the pulse generation circuit; and a secondary-side detection circuit for detecting at least any one of the voltage value supplied to the pulse generation circuit, the current value flowing through the secondary-side coil or the pulse generation circuit, and the magnitude of the magnetic flux generated from the primary-side coil. When the power transmission device detects an increase in the magnetic flux linked to the primary-side coil or the magnetic flux near the primary-side coil through the primary-side detection circuit, it transfers from the standby state to a power transmission state in which a power transmission current flows through the primary-side coil, and the magnetic flux generation circuit adjusts the generated magnetic flux using the detection value of the secondary-side detection circuit.

[0008] According to this aspect, the power transmission device detects an increase in the magnetic flux linked to the primary-side coil or the magnetic flux near the primary-side coil generated by the magnetic flux generation circuit through the primary-side detection circuit, and thereby transfers from the standby state to the power transmission state. Therefore, the non-contact power supply system can start non-contact power supply as early as possible. In addition, the magnetic flux generation circuit can appropriately control the magnitude of the magnetic flux generated by the magnetic flux generation coil by adjusting the generated magnetic flux using the detection value of the secondary-side detection circuit.

[0009] According to a second aspect of the present disclosure, there is provided a power receiving device that is powered in a non-contact manner from a power transmitting device. The power transmitting device includes: a primary side resonance circuit having a primary side coil and a primary side capacitor; an AC power supply that applies AC power of a predetermined operating frequency to the primary side resonance circuit; and a primary side detection circuit that detects the magnitude of the magnetic flux linked to the primary side coil or the magnitude of the magnetic flux near the primary side coil. The power receiving device includes: a secondary side resonance circuit having a secondary side coil and a secondary side capacitor that are magnetically coupled to the primary side coil; a magnetic flux generation circuit having: a magnetic flux generation coil that generates a magnetic flux radiated to the primary side coil in a standby state of the power transmitting device; a pulse generation circuit that supplies AC power to the magnetic flux generation coil; and a secondary side control circuit that controls the pulse generation circuit; and a secondary side detection circuit that detects at least any one of the voltage value supplied to the pulse generation circuit, the current value flowing through the secondary side coil or the pulse generation circuit, and the magnitude of the magnetic flux generated from the primary side coil. When the power transmitting device detects an increase in the magnetic flux linked to the primary side coil or the magnetic flux near the primary side coil through the primary side detection circuit, it transfers from the standby state to a power transmission state in which a power transmission current flows through the primary side coil. The magnetic flux generation circuit adjusts the generated magnetic flux using the detection value of the secondary side detection circuit.

[0010] According to this aspect, the power transmitting device detects an increase in the magnetic flux linked to the primary side coil or the magnetic flux near the primary side coil generated by the magnetic flux generation circuit through the primary side detection circuit, and thereby transfers from the standby state to the power transmission state. Therefore, the non-contact power supply system can start non-contact power supply as early as possible. In addition, the magnetic flux generation circuit can appropriately control the magnitude of the magnetic flux generated by the magnetic flux generation coil by adjusting the generated magnetic flux using the detection value of the secondary side detection circuit.

[0011] According to a third aspect of the present disclosure, there is provided a power transmission device that supplies power to a power receiving device in a non-contact manner. The power transmission device includes: a primary-side resonance circuit having a primary-side coil and a primary-side capacitor; an AC power source that applies AC power of a predetermined operating frequency to the primary-side resonance circuit; and a primary-side detection circuit that detects the magnitude of the magnetic flux linked to the primary-side coil or the magnitude of the magnetic flux near the primary-side coil. The power receiving device includes: a secondary-side resonance circuit having a secondary-side coil for magnetic coupling with the primary-side coil and a secondary-side capacitor; a magnetic flux generation circuit having: a magnetic flux generation coil that generates magnetic flux radiated to the primary-side coil in a standby state of the power transmission device; a pulse generation circuit that supplies AC power to the magnetic flux generation coil; and a secondary-side control circuit that controls the pulse generation circuit; and a secondary-side detection circuit that detects at least any one of the voltage value supplied to the pulse generation circuit, the current value flowing through the secondary-side coil or the pulse generation circuit, and the magnitude of the magnetic flux generated from the primary-side coil. The magnetic flux generation circuit adjusts the generated magnetic flux using the detection value of the secondary-side detection circuit. The power transmission device transfers from the standby state to a power transmission state in which a power transmission current flows through the primary-side coil when an increase in the magnetic flux linked to the primary-side coil or the magnetic flux near the primary-side coil is detected by the primary-side detection circuit.

[0012] According to this aspect, the power transmission device detects an increase in the magnetic flux linked to the primary-side coil or the magnetic flux near the primary-side coil generated by the magnetic flux generation circuit through the primary-side detection circuit, and thus transfers from the standby state to the power transmission state. Therefore, the non-contact power supply system can start non-contact power supply as early as possible. In addition, the magnetic flux generation circuit can appropriately control the magnitude of the magnetic flux generated by the magnetic flux generation coil by adjusting the generated magnetic flux using the detection value of the secondary-side detection circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The above objects, other objects, features, and advantages of the present disclosure can be made more apparent by referring to the accompanying drawings and the following detailed description. The accompanying drawings are as follows. Figure 1 is a schematic configuration diagram of a non-contact power supply system. Figure 2 is a circuit diagram of the non-contact power supply system according to the first embodiment. Figure 3 is a diagram showing a time change in the positional relationship between the primary-side coil and the secondary-side coil. Figure 4 is a diagram showing a power supply start sequence according to the first embodiment. Figure 5 is a diagram showing the waveform of a control signal. Figure 6It is a diagram showing the relationship between the drive frequency and the current flowing through the secondary side coil. Figure 7 It is a diagram showing the relationship between the standby time and each period of the burst drive. Figure 8 It is a diagram showing the relationship between the vehicle speed and the burst period. Figure 9 It is a circuit diagram of the contactless power supply system of the second embodiment. Figure 10 It is a diagram showing the power supply start sequence of the second embodiment. Figure 11 It is a diagram explaining the control of the pulse generation circuit. Figure 12 It is a diagram explaining the equivalent circuit and the calculation method of the coupling coefficient. Figure 13 It is a circuit diagram of the contactless power supply system of the third embodiment. Figure 14 It is a diagram showing the power supply start sequence of the third embodiment. Figure 15 It is the first flowchart showing the abnormality detection process of the fourth embodiment. Figure 16 It is the second flowchart showing the abnormality detection process of the fourth embodiment. Figure 17 It is a circuit diagram of the power receiving device of the fifth embodiment. Figure 18 It is a circuit diagram of the power receiving device of the sixth embodiment. Figure 19 It is a circuit diagram of the power receiving device of the seventh embodiment. Detailed Embodiments

[0014] A. First Embodiment: A1. Structure of the Contactless Power Supply System: As Figure 1 shown, 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 the road RS. The power receiving device 80 is installed on a vehicle VE as a moving body traveling on the road RS. During the travel of the vehicle VE, the power receiving device 80 is powered from the power transmission device 10. Here, the travel includes the case where the vehicle VE moves and the case where the vehicle stops due to waiting for a signal or the like. The vehicle VE is configured as an electric vehicle or a hybrid vehicle, for example.

[0015] The power transmission device 10 has: a primary side resonance circuit 12 having a primary side coil L1; and an AC power supply 11 that supplies power to the primary side resonance circuit 12. The AC power supply 11 supplies power to a plurality of primary side resonance circuits 12. The plurality of primary side coils L1 are arranged along the extension direction of the road RS.

[0016] In addition, the moving body equipped with the power receiving device 80 is not limited to the vehicle VE traveling on the road RS. For example, it can also be an AGV (Automated Guided Vehicle), a traveling robot, etc. In addition, the power transmitting device 10 may not be provided under the road RS, but may be provided on the sidewalk or parking lot adjacent to the road RS, or on the path where the AGV travels.

[0017] The power receiving device 80 includes a battery 84, an auxiliary battery 94, a pulse generation circuit 82, a secondary side resonance circuit 81 having a secondary side coil L2, a DC / DC converter 92, an inverter 91, an electric generator 93, an auxiliary machine 95, a power receiving side control unit 96, and a vehicle speed sensor 97 as a speed acquisition unit. In the present embodiment, the secondary side coil L2 is provided at a position opposite to the primary side coil L1, that is, on the lower surface of the vehicle VE.

[0018] The pulse generation circuit 82 is connected to the secondary side resonance circuit 81. In the present embodiment, the pulse generation circuit 82 functions as a rectifier in the power receiving state of the power receiving device 80 described later, and functions as an inverter in the non-power receiving state of the power receiving device 80 described later. In the power receiving state, the pulse generation circuit 82 converts the AC power received by the secondary side resonance circuit 81 into DC power, and supplies the converted DC power to the battery 84, the DC / DC converter 92, and the inverter 91.

[0019] The battery 84 is a secondary battery that is charged by the supplied DC power. The inverter 91 uses the supplied DC power to drive the electric generator 93. The electric generator 93 operates as a three-phase AC motor and generates a driving force for traveling. In addition, the electric generator 93 operates as a generator when the vehicle VE decelerates, and regenerates power. The regenerated three-phase AC power is converted into DC power by the inverter 91 and used for charging the battery 84.

[0020] The DC / DC converter 92 steps down the DC power supplied from the pulse generation circuit 82, and supplies the stepped-down DC power to the auxiliary battery 94 and the auxiliary machine 95. The auxiliary machine 95 includes peripheral devices such as an air conditioning device, an electric power steering device, headlights, turn signals, windshield wipers, etc. of the vehicle VE, and accessories of the vehicle VE. The auxiliary battery 94 is a secondary battery for driving the auxiliary machine 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.

[0021] The power receiving side control unit 96 controls each part in the power receiving device 80, such as the inverter 91. The power receiving side control unit 96 is implemented by including an ECU (engine control unit). In addition, the ECU can be implemented by one microcontroller or by including multiple microcontrollers. The case of including multiple microcontrollers is, for example, the case of including 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 generation circuit 82.

[0022] A2. Circuit structure of the non-contact power supply system: As Figure 2 shown, in addition to the above structure, the power transmission device 10 further includes a primary side capacitor C1 as 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 part 14. The primary side coil L1 is connected in series with the primary side capacitor C1 to form a primary side resonance circuit 12. In addition, in Figure 2 only one primary side resonance circuit 12 among the multiple primary side resonance circuits 12 connected to the AC power supply 11 is shown, and the illustration of the other primary side resonance circuits 12 is omitted.

[0023] The AC power supply 11 applies AC power with a predetermined operating frequency to the primary side resonance circuit 12. In this embodiment, the operating frequency is 85 kHz. The primary side capacitor C1 has a function of making the primary side resonance circuit 12 into a resonance state at the operating frequency and making the primary side resonance circuit 12 into a non-resonance state at the operating frequency. In this embodiment, the primary side capacitor C1 is configured to be able to switch to a first capacitance value and a second capacitance value smaller than the first capacitance value. Moreover, the capacitance value of the primary side capacitor C1 is switched to either the first capacitance value or 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 is at the first capacitance value, the primary side resonance circuit 12 becomes a resonance state at the operating frequency. That is, the first capacitance value of the primary side capacitor C1 is set to a value at which the resonance frequency of the primary side resonance circuit 12 coincides with the operating frequency. In contrast, when the primary side capacitor C1 is at the second capacitance value, since the resonance frequency of the primary side resonance circuit 12 deviates from the operating frequency, the primary side resonance circuit 12 becomes a non-resonance state at the operating frequency.

[0024] The primary-side voltage sensor M1 is provided to detect the magnitude of the magnetic flux linked with the primary-side coil L1. The primary-side voltage sensor M1 detects the voltage induced in the primary-side coil L1 due to the change in the magnetic flux linked with the primary-side coil L1. The primary-side voltage sensor M1 detects the voltage value of the primary-side coil L1 and outputs a signal representing the detected voltage value to the primary-side control circuit 13. The primary-side control circuit 13 uses the signal output from the primary-side voltage sensor M1 to output a switching signal Sig1 to the primary-side capacitor C1. Specifically, the primary-side control circuit 13 outputs the switching signal Sig1 when the voltage value indicated by the signal is greater than a predetermined threshold value.

[0025] In addition, the primary-side detection circuit is not limited to the structure for detecting the voltage of the primary-side coil L1, and may also be a current sensor for detecting the current flowing through the primary-side coil L1. Alternatively, the primary-side detection circuit may also be a magnetic sensor for detecting the magnitude of the magnetic flux near the primary-side coil L1. Specifically, it is a magnetic sensor having a coil provided near the primary-side coil L1 built therein. In addition, when the primary-side detection circuit is a magnetic sensor, the power transmission device 10 transfers from the standby state to the power transmission state when it detects an increase in the magnetic flux near the primary-side coil L1 in step S4 described later.

[0026] The detected portion 14 is a two-dimensional code displayed on the surface of the road RS. As the two-dimensional code, various two-dimensional codes such as QR Code (registered trademark), micro QR Code, iQR Code (registered trademark), and PDF417 can be used, for example.

[0027] In addition to the above structure, the power reception device 80 further includes a secondary-side capacitor C2, a secondary-side voltage sensor M2 as a secondary-side detection circuit, a secondary-side control circuit 85, and a device detection portion 87. The secondary-side coil L2 is connected in series with the secondary-side capacitor C2 to form a secondary-side resonance circuit 81. In the present embodiment, the secondary-side coil L2 functions as a power reception coil and also functions as a magnetic flux generation coil for generating a magnetic flux radiated to the primary-side coil L1. Moreover, a magnetic flux generation circuit 86 is constituted by the secondary-side coil L2 as the magnetic flux generation coil, a pulse generation circuit 82, and the secondary-side control circuit 85.

[0028] The pulse generation circuit 82 is configured as a synchronous rectification circuit. Specifically, the pulse generation circuit 82 includes four switching elements Q1, Q2, Q3, Q4 and a smoothing capacitor C3. The four switching elements Q1, Q2, Q3, Q4 form a bridge circuit. Thus, in the power receiving state where AC power is supplied from the secondary side resonant circuit 81, it functions as a rectifier, and in the non-power receiving state where DC power is supplied from the battery 84, it functions as an inverter. In the present embodiment, the switching elements Q1 to Q4 are implemented by MOSFETs (metal-oxide-semiconductor field-effect transistors). In addition, the details of the pulse generation circuit 82 will be described later. The power sources of the secondary side control circuit 85 and the device detection unit 87 are the battery 84.

[0029] The secondary side voltage sensor M2 as the secondary side detection circuit is a voltage detection circuit that detects the output voltage value of the battery 84 and outputs a signal representing 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 control signals to the respective gate terminals of the switching elements Q1 to Q4. In addition, the details of the driving performed by the secondary side control circuit 85 will be described later.

[0030] The device detection unit 87 detects the detected unit 14. The device detection unit 87 is a QR code reader capable of reading two-dimensional codes. In the present embodiment, the device detection unit 87 detects a QR code (registered trademark) by imaging. When the detected QR code (registered trademark) is a pre-determined 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 cause the pulse generation circuit 82 to supply AC power.

[0031] When the primary side coil L1 and the secondary side coil L2 are magnetically coupled, the resonance frequencies of the primary side resonant circuit 12 and the secondary side resonant circuit 81 are set to be substantially the same. Thus, non-contact power supply to the power receiving device 80 can be performed through the magnetic resonance of the primary side coil L1 and the secondary side coil L2. As described above, the DC power output from the secondary side resonant circuit 81 is rectified by the pulse generation circuit 82 and supplied to the battery 84.

[0032] A3. Standby state and power transmission state: As Figure 3 shown, the primary side coils L1 are arranged along the extension direction of the road RS, and the secondary side coil L2 receives non-contact power supply from the nearest primary side coil L1. In Figure 3In it, the primary side coil L1 and the secondary side coil L2 for power transmission are shown by hatched lines. That is, the primary side coil L1 without hatched lines is the primary side coil L1 in the standby state, and the primary side coil L1 with hatched lines is the primary side coil L1 in the power transmission state. Figure 3 The arrow shown indicates the traveling direction of the vehicle VE equipped with the secondary side coil L2. At Figure 3 the "time t1" shown depicts the appearance of the secondary side coil L2 approaching the arranged primary side coil L1. As Figure 3 shown at the "time t2", when the secondary side coil L2 approaches the primary side coil L1 at the end, the power supply start sequence described later is performed, and non-contact power supply starts. As Figure 3 shown at the "time t3", the vehicle VE travels. When the distance between the adjacent primary side coil L1 of the primary side coil L1 at the end and the secondary side coil L2 is shorter than the distance between the primary side coil L1 at the end and the secondary side coil L2, the primary side coil L1 for power transmission is switched from the primary side coil L1 at the end to the adjacent primary side coil L1 of the primary side coil L1 at the end.

[0033] In addition, in the direction of the coil center axis of the primary side coil L1, not only as Figure 3 shown at the "time t3", power is transmitted in a state where all of the primary side coil L1 faces the secondary side coil L2, but also as Figure 3 shown at the "time t2", power is also transmitted in a state where only a part of the primary side coil L1 faces the secondary side coil L2.

[0034] A4. Power supply start sequence: The non-contact power supply system 1 starts and stops power supply between the power transmission device 10 and the power reception device 80 without using communication. In addition, in the present embodiment, when the power reception side control unit 96 permits power reception of the secondary side resonance circuit 81, it outputs a power supply permission signal to the secondary side control circuit 85. And when the power reception side control unit 96 prohibits power supply to the secondary side resonance circuit 81, it outputs a power supply prohibition signal to the secondary side control circuit 85. The power reception side control unit 96 outputs a power supply prohibition signal, for example, when the state of the battery 84 is not a state suitable for charging. In the following description, for ease of understanding, each step is used for explanation.

[0035] When the power reception device 80 approaches the power transmission device 10, in Figure 4 step S1, the device detection unit 87 of the power reception device 80 detects the detected unit 14 of the power transmission device 10. When the device detection unit 87 detects the detected unit 14, it outputs a signal Sig2 to the secondary side control circuit 85.

[0036] When the secondary - side control circuit 85 receives the input of the signal Sig2, in step S2, it confirms whether a power - supply permission signal is input. When a power - supply permission signal is input, the device detection unit 87 drives the pulse generation circuit 82 to cause the secondary - side coil L2 to supply AC power at a frequency of the resonance frequency or a frequency close to the resonance frequency. Thus, in Figure 4 step S3, the secondary - side coil L2, which functions as a magnetic - flux generation coil, generates magnetic flux. As a result, the magnetic flux linked to the primary - side coil L1 increases, an electromotive force is generated in the primary - side coil L1 by electromagnetic induction, and the voltage of the primary - side coil L1 increases.

[0037] In addition, when a power - supply prohibition signal instead of a power - supply permission signal is input, the secondary - side control circuit 85 does not perform step S3, but sets the pulse generation circuit 82 to a stop state described later. Thus, power supply can be avoided when the battery 84 is not in a state suitable for charging. As another embodiment, when a power - supply prohibition signal is input, the secondary - side control circuit 85 may not execute step S3 and transfer to a permission - signal standby state waiting for the input of a power - supply permission signal, and start driving triggered by the input of a power - supply start signal to execute step S3. Thus, even when a power - supply prohibition signal is input when the signal Sig2 is input, power supply can be received by the input of a power - supply start signal.

[0038] In Figure 4 step S4, when the primary - side control circuit 13 detects an increase in the magnetic flux linked to the primary - side coil L1, it outputs a switching signal Sig1 to the primary - side capacitor C1. Specifically, when it is determined that the voltage value indicated by the signal output from the primary - side voltage sensor M1 is greater than the threshold value, the primary - side control circuit 13 outputs a switching signal Sig1 to the primary - side capacitor C1. Thus, in Figure 4In step S5, the capacitance value of the primary capacitor C1, which is an impedance variable element, is switched from the second capacitance value to the first capacitance value. As a result, the primary resonance circuit 12 becomes a resonance state at the resonance frequency fs, and transitions to a power transmission state in which a power transmission current flows through the primary coil L1, and power supply starts. In this way, when the power transmission device 10 detects an increase in the magnetic flux linked to the primary coil L1 through the primary voltage sensor M1, it transitions from the standby state to the power transmission state. At the moment when the capacitance value of the primary capacitor C1 is switched, the power transmission device 10 transitions from the standby state to the power transmission state. In step S6, which is a switching process, the driving method of the pulse generation circuit 82 is switched from the rest driving described later to the rectification driving in which the pulse generation circuit 82 functions as a rectifier. As a result, the power receiving device 80 transitions from the non-power receiving state to the power receiving state. Specifically, the secondary side control circuit 85 detects the start of power transmission from the power transmission device 10, for example, by detecting, with a voltage sensor (not shown) that detects the source-drain voltage of the switching element Q4, the current flowing in the current path passing through the body diodes of the switching element Q1 and the switching element Q4 due to the electromotive force generated in the secondary coil L2. Then, in the power receiving state, the secondary side control circuit 85 rectification-drives the pulse generation circuit 82 according to the phase of the AC power received by the secondary coil L2 so that the pulse generation circuit 82 functions as a rectifier. As described above, non-contact power supply between the power transmission device 10 and the power receiving device 80 is started without using communication, so non-contact power supply can be started earlier than in the case of starting power supply using communication.

[0039] A5. Control of the secondary side control circuit: In Figure 3 step S3, the pulse generation circuit 82 converts the DC power supplied from the battery 84 into AC power and inputs it to the secondary resonance circuit 81. Here, the output voltage value of the battery 84 may deviate from the target voltage value Vtg ( Figure 6 ). In addition, the current value flowing through the secondary coil L2 is proportional to the output voltage value of the battery 84. Therefore, when the output voltage value of the battery 84 is lower than the target voltage value Vtg, in step S3, the magnetic flux generated in the secondary coil L2 is smaller than the target magnetic flux, and although the secondary coil L2 is close, the magnetic flux linked to the primary coil L1 becomes smaller, and power supply may not start. 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 in the secondary coil L2 is larger than the target magnetic flux, and a failure may occur in the primary resonance circuit 12. Therefore, in the present embodiment, the output power value of the battery 84 is used to appropriately drive the pulse generation circuit 82. As a result, the magnitude of the magnetic flux generated in the secondary coil L2 in step S3 can be appropriately set.

[0040] As described above,Figure 2 The pulse generation circuit 82 shown has four switching elements Q1, Q2, Q3, and Q4. When the secondary side control circuit 85 causes the pulse generation circuit 82 to function as an inverter, the switching elements Q1 and Q2 that form the upper arm are driven complementarily to each other, and the upper arm is connected to the positive terminal of the battery 84. Similarly, the secondary side control circuit 85 drives the switching elements Q3 and Q4 that form the lower arm complementarily to each other, and the lower arm is connected to the negative terminal of the battery 84. Also, the switching elements Q1 and Q4 are set to the ON state by simultaneously inputting an ON signal to each other, and are set to the OFF state by simultaneously inputting an OFF signal to each other. Similarly, the switching elements Q2 and Q3 are set to the ON state by simultaneously inputting an ON signal to each other, and are set to the OFF state by simultaneously inputting an OFF signal to each other.

[0041] Figure 5 It is a diagram showing the waveforms of the control signals input to the switching elements Q1 and Q4. As Figure 5 shown, the secondary side control circuit 85 periodically repeats the supply drive for supplying AC power from the pulse generation circuit 82 to the secondary side coil L2 and the rest drive for stopping the pulse generation circuit 82 from supplying AC power to the secondary side coil L2 in the non-power receiving state. Specifically, the secondary side control circuit 85 performs burst drive, which periodically repeats the drive period Td of outputting an ON signal and the rest period Tp of not outputting an ON signal in the second period T2. Thereby, the pulse generation circuit 82 is driven intermittently. That is, the secondary side control circuit 85 outputs an ON signal to the pulse generation circuit 82 during the supply drive, and does not output an ON signal to the pulse generation circuit 82 during the rest drive. Here, the ON signal is a high-level signal for making the switching element Q1 in the ON state in the case of the switching element Q1. In addition, the OFF signal is a low-level signal for making the switching element Q1 in the OFF state in the case of the switching element Q1. The same applies to the switching elements Q2 to Q3. During the rest 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 generation circuit 82. Here, the duty ratio is the ratio of the ON period Ton of outputting an ON signal during the drive period Td to the first period T1.

[0042] When the frequency of the AC power input to the secondary side resonance circuit 81 is the resonance frequency fs ( Figure 6) When this occurs, the current flowing through the secondary-side coil L2 is at its maximum. Moreover, when the frequency of the AC power input to the secondary-side resonant circuit 81 deviates from the resonant frequency fs, the current flowing through the secondary-side 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-side coil L2 can be adjusted by adjusting the drive frequency of the pulse generation circuit 82. Additionally, using the first period T1, the drive frequency of the pulse generation circuit 82 is (1 / T1).

[0043] Furthermore, by adjusting the duty ratio of the control signal input to the pulse generation circuit 82, the effective voltage of the AC power input to the secondary-side resonant circuit 81 can be adjusted. Thereby, the current flowing through the secondary-side coil L2 can be adjusted. Specifically, the smaller the duty ratio, the smaller the effective voltage of the AC power input to the secondary-side resonant circuit 81, and the smaller the current flowing through the secondary-side coil L2.

[0044] Figure 6 is a graph showing the relationship between the drive frequency (horizontal axis) and the current flowing through the secondary-side coil L2 (vertical axis). Figure 6 The characteristic line Ds shown is the characteristic line when the output voltage value of the battery 84 is the target voltage value Vtg. The characteristic line D1 is the characteristic line when the output voltage value of the battery 84 is less than the target voltage value Vtg. The characteristic line D1 is the characteristic line when the voltage of the battery 84 is less than the target voltage value Vtg. The duty ratios of the characteristic lines Ds, D1, and D2 are all the same and are the reference duty ratio.

[0045] As Figure 6 shown, the target value of the current value flowing through the secondary-side coil L2, that is, the target current value Itg, is the current value flowing through the secondary-side 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 the reference duty ratio. The reference frequency fd is less than the resonant frequency fs. And when the output voltage value of the battery 84 is higher than the target voltage value Vtg, the secondary-side control circuit 85 decreases the duty ratio from the reference duty ratio to thereby reduce the voltage value supplied to the secondary-side coil L2. Thereby, the current value flowing through the secondary-side coil L2 can be adjusted to the target current value Itg. In contrast, when the output voltage value of the battery 84 is lower than the target voltage value Vtg, the secondary-side control circuit 85 increases the drive frequency from the reference frequency fd to approach the resonant frequency fs. Thereby, the current flowing through the secondary-side coil L2 can be adjusted to the target current value Itg. Therefore, even when the output voltage value of the battery 84 deviates from the target voltage value Vtg, an appropriate current can be supplied to the secondary-side coil L2. In the present embodiment, the reference duty ratio is 50%.

[0046] In addition, 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, when the output voltage value is higher than the target voltage value Vtg, the duty ratio is adjusted, and when the output voltage value is lower than the target voltage value Vtg, the driving frequency is adjusted, but regardless of whether the output voltage value is higher or lower than the target voltage value Vtg, by adjusting at least one of the driving frequency and the duty ratio, the current value flowing through the secondary side coil L2 can be adjusted to the target current value Itg.

[0047] In addition, when the detection value of the secondary side voltage sensor M2 is outside the predetermined range, the secondary side control circuit 85 stops the supply of AC power by the pulse generating circuit 82. Specifically, Figure 4 As shown, when the detection value of the secondary-side voltage sensor M2 is less than the first threshold value Vth1 and greater than the second threshold value Vth2, the operation of the pulse generating circuit 82 is stopped. Specifically, a disconnection signal is input to all the switching elements Q1 to Q4. When the output voltage value of the battery 84 is less than the first threshold value Vth1, for example, the battery 84 may not be properly connected. In addition, when the battery voltage is greater than the second threshold value Vth2, for example, it is considered that the battery 84 is abnormal. In the case of such an abnormal state, by stopping the current supply to the secondary-side coil L2, it is possible to avoid the generation of an overvoltage in the secondary-side control circuit 85 due to the start of power reception in the secondary-side resonant circuit 81 after the power transmission device 10 is transferred to the power transmission state.

[0048] Furthermore, in the contactless power supply system 1, a method is implemented to prevent the magnetic flux generated by the secondary coil L2 and the magnetic flux generated by the primary coil L1 from overlapping. Figure 7 As shown in the "first case" of , the period from step S4 to step S5 of the power transmitting device 10 is set to be longer than the driving period Td of the power receiving device 80. As described above, the secondary side control circuit 85 supplies drive to 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 side coil L2. In step S4, after the increase of the magnetic flux interlinked with the primary side coil L1 is detected by the primary side voltage sensor M1, the power transmitting device 10 transitions to the power transmitting state by performing step S5 after a standby time. The standby time is a time that is longer than the response time of the primary side control circuit 13 to perform step S4. Furthermore, the standby time is a predetermined time for the power transmitting device 10 to transition to the power transmitting state during the idle period Tp of the power receiving device 80. Therefore, even in the case where step S4 is performed at the start time of the driving period Td, step S5 is performed during the idle period Tp. In addition, as Figure 7As shown in the "second case", the length of the standby time is set such that step S5 is performed during the rest period Tp even when step S4 is performed at the end of the drive period Td. Thereby, it is possible to avoid the overlap of the magnetic flux generated by the secondary side coil L2 and the magnetic flux generated by the primary side coil L1, and thus avoid the generation of overvoltage and overcurrent.

[0049] In addition, the secondary side control circuit 85 adjusts the period of the rest drive using the vehicle speed, specifically, the length of the rest period Tp. As Figure 8 shown, when the vehicle speed is greater than the reference speed, the rest period Tp is made longer than the reference length. On the other hand, when the vehicle speed is less than the reference speed, the rest period Tp is made shorter than the reference length. In the non-contact power supply system 1, when the secondary side coil L2 approaches a position where non-contact power supply can be performed from the primary side coil L1, non-contact power supply starts. The temporal change in the distance between the primary side coil L1 and the secondary side coil L2 depends on the moving speed of the vehicle VE. Therefore, by adjusting the rest period Tp according to the moving speed, it is possible to perform step S3 at an appropriate time interval corresponding to the temporal change in the distance between the primary side coil L1 and the secondary side coil L2. Specifically, the time of the rest period Tp is set using a map in which the relationship between the vehicle speed and the time of the rest period Tp is previously corresponded. This map is stored in the power receiving side control unit 96, and the time of the rest 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, it may be that this map is stored in the secondary side control circuit 85, and the secondary side control circuit 85 sets the time of the rest period Tp using the signal indicating the vehicle speed output from the power receiving side control unit 96.

[0050] According to the first embodiment described above, when the power transmission device 10 detects an increase in the magnetic flux linked to the primary side coil L1 through the primary side voltage sensor M1, it transfers from the standby state to the power transmission state. Thereby, non-contact power supply can be started earlier. In addition, the magnetic flux generation circuit 86 adjusts the magnitude of the magnetic flux generated by the secondary side coil L2 using the detection value of the secondary side voltage sensor M2. Thereby, it is possible to appropriately adjust the magnetic flux density of the magnetic flux generated in the secondary side coil L2 for causing the power transmission device 10 to start power transmission.

[0051] In addition, the secondary side control circuit 85 adjusts the magnitude of the generated magnetic flux using the voltage value detected by the primary side voltage sensor M1 that detects the output voltage value of the battery 84 in the non-power receiving state. Thereby, even when the output voltage value of the battery 84 deviates from the target voltage value Vtg, it is possible to appropriately adjust the magnetic flux generated in the secondary side coil L2.

[0052] In addition, 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 generation circuit 82. Thus, the secondary-side control circuit 85 can adjust the generated magnetic flux by adjusting either the drive frequency or the duty ratio.

[0053] In addition, when the detected value of the secondary-side voltage sensor M2 is less than the first threshold value Vth1 and greater than the second threshold value Vth2, the secondary-side control circuit 85 stops the supply of the alternating current of the pulse generation circuit 82. Thus, in the case where an abnormality occurs in the power receiving device 80, the operation of the pulse generation circuit 82 can be stopped, and overvoltage generated in the secondary-side control circuit 85 due to the start of power reception in the secondary-side resonance circuit 81 after the power transmission device 10 is transferred to the power transmission state can be avoided.

[0054] In addition, after the power transmission device 10 detects an increase in the magnetic flux near the primary-side coil L1 through the primary-side detection circuit in step S4, after a standby time, it is transferred to the power transmission state in step S5. Thus, the overlap of the magnetic flux generated by the secondary-side coil L2 and the magnetic flux generated by the primary-side coil L1 can be avoided, and the generation of overvoltage and overcurrent can be avoided.

[0055] In addition, in the case where a power supply prohibition signal is input, the secondary-side control circuit 85 does not perform step S3. Thus, power supply in a state where the battery 84 is not suitable for charging can be avoided. In the case where a power supply prohibition signal is input, the secondary-side control circuit 85 does not execute step S3 and is transferred to the permission signal standby state waiting for the input of a power supply permission signal, and step S3 is executed triggered by the input of a power supply start signal. Thus, even in the case where a power supply prohibition signal is input when the input signal Sig2 is input, power supply can be received by the input of a power supply start signal.

[0056] In addition, the secondary-side control circuit 85 adjusts the length of the rest period Tp according to the vehicle speed. Thus, the secondary-side control circuit 85 can perform step S3 at an appropriate time interval corresponding to the temporal change in the distance between the primary-side coil L1 and the secondary-side coil L2.

[0057] B. Second Embodiment: As Figure 9 shown, the circuit structure of the power transmission device 210 and the circuit structure of the power receiving device 280 in the non-contact power supply system 201 of the present embodiment are different from those of the first embodiment. The same reference numerals are given to the same structures as those in the first embodiment, and the detailed description is appropriately omitted.

[0058] The structure for changing the impedance of the primary - side resonant circuit 212 in the power transmission device 210 of this embodiment is different from that of the power transmission device 10 of the first embodiment. The power transmission device 210 has a first switch SW1 and capacitors C21 and C22. The capacitor C22 is connected in parallel with the connection body of 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.

[0059] When a high - level switching signal Sig3 is input to the first switch SW1, the first switch SW1 becomes in the on - state, and current flows through the capacitor C21. Here, the combined capacitance of the capacitors C21 and C22 and the inductance of the primary - side coil L1 are set to values that become a resonant state at the operating frequency. Thus, when the first switch SW1 becomes in the on - state, the primary - side resonant circuit 212, which is a series - resonant circuit, is formed by the capacitors C21, C22, and the primary - side coil L1. In contrast, when a low - level switching signal Sig3 is input to the first switch SW1, the first switch SW1 becomes in the off - state, and the capacitor C21 becomes in the non - conducting state. Moreover, the resonant vibration frequency of the resonant circuit formed by the capacitor C22 and the primary - side coil L1 deviates from the operating frequency, so the primary - side coil L1 becomes in the 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 becomes larger, and the current flowing through the primary - side resonant circuit 212 is suppressed. The current flowing through the primary - side coil L1 in the standby state is called the standby current.

[0060] The power receiving device 280 of this embodiment has a magnetic flux detection circuit 281 instead of the secondary side voltage sensor M2 of the first embodiment. The magnetic flux detection circuit 281 serves as a secondary side detection circuit for detecting the magnitude of the magnetic flux radiated from the primary side coil L1. The magnetic flux detection circuit 281 detects the magnitude of the magnetic flux generated from the primary side coil L1. Specifically, the magnetic flux detection circuit 281 has a detection coil Lsp disposed near the secondary side coil L2, and uses the voltage of the detection coil Lsp to detect the magnitude of the magnetic flux density. The magnetic flux detection circuit 281 outputs a signal Sig4 representing the detected magnitude of the magnetic flux density to the secondary side control circuit 285. In detail, the detection coil Lsp is disposed at a position magnetically coupled to the primary side coil L1 when the primary side coil L1 and the secondary side coil L2 are magnetically coupled. Thereby, the detection coil Lsp can detect the magnitude of the magnetic flux linked with the primary side coil L1 in the case where no magnetic flux is generated in the secondary side coil L2. In addition, "detecting the magnitude of the magnetic flux linked with the primary side coil L1" includes not only the case of detecting all the magnetic flux linked with the primary side coil L1, but also the case of detecting a part of the magnetic flux linked with the primary side coil L1 as in this embodiment. In this embodiment, the longer the distance from the primary side coil L1, the smaller the magnetic flux density detected by the secondary side voltage sensor M2. That is, the detected value of the secondary side voltage sensor M2 varies not only according to the magnitude of the magnetic flux generated from the primary side coil L1, but also according to the distance between the primary side coil L1 and the secondary side voltage sensor M2.

[0061] The power supply start sequence of this embodiment is different from that of the first embodiment. In Figure 10 the standby state of the power transmission device 10 shown, the first switch SW1 is set to the off state, so that a standby current flows through the primary side coil L1. In step S21, the standby current flows through the primary side coil L1, so that the primary side coil L1 generates a magnetic flux.

[0062] When the secondary side coil L2 approaches the primary side coil L1, in step S22, the magnetic flux density detected by the magnetic flux detection circuit 281 increases. When the magnetic flux density indicated by the signal Sig4 is greater than a predetermined threshold value, the secondary side control circuit 285 outputs an on signal to the pulse generation circuit 82 and drives it. Thereby, in step S25, the secondary side coil L2 serving as a magnetic flux generating coil generates a magnetic flux. Thereby, the magnetic flux linked with the primary side coil L1 is amplified.

[0063] In step S26, the primary - side control circuit 13 switches the voltage level of the switching signal Sig3 based on the detection value of the primary - side voltage sensor M1 which is the primary - side detection circuit. Specifically, when it is determined that the magnetic flux linked to the primary - side coil L1 is amplified, that is, when it is determined that the voltage value indicated by the signal output from the primary - side voltage sensor M1 is greater than the threshold value, a switching signal Sig3 with a high level is output to the first switch SW1. Thereby, in step S25, the combined capacitance of the capacitors C21 and C22 which are impedance - variable elements is changed. As a result, the primary - side resonant circuit 212 becomes a resonant state at the operating frequency and starts power supply.

[0064] In the present embodiment, after the secondary - side control circuit 285 supplies and drives the pulse - generation circuit 82, when the detection value of the magnetic - flux detection circuit 281 is within a pre - determined magnetic - flux range, the standby drive continues for a time longer than a pre - determined time. Specifically, after performing step S25, the secondary - side control circuit 285 performs step S28 during the standby 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 pre - determined first threshold value. Moreover, when the magnetic - flux density indicated by the signal Sig4 is greater than the first threshold value, since the power transmission of the power - transmission device 210 is in progress, the secondary - side control circuit 285 does not change the time of the pre - determined standby period Tp. Additionally, in this case, that is, when the power transmission of the power - transmission device 210 is in progress, the secondary - side control circuit 285 uses a voltage sensor (not shown) to detect the power reception in the secondary - side coil L2, so that the pulse - generation circuit 82 functions as a rectifier. In contrast, when the magnetic - flux density indicated by the signal Sig4 is equal to or less than the first threshold value, since the power transmission of the power - transmission device 210 has stopped, or the distance between the primary - side coil L1 and the secondary - side coil L2 is too long for the secondary - side coil L2 to receive the transmitted power, the secondary - side control circuit 285 extends the time of the pre - determined standby period Tp, and makes the standby drive continue for a period longer than the pre - determined period. By extending the period of the standby operation in which the pulse - generation circuit 82 is not driven, the power consumption of the battery 84 can be suppressed. In addition, the secondary - side control circuit 285 can drive the pulse - generation circuit 82 after the standby drive continues for a period longer than the pre - determined period, and can also continue the standby drive for a period longer than the pre - determined period. As described above, the magnetic - flux range means the case where the detection value is equal to or less than the first threshold value.

[0065] In addition, when the detection value of the magnetic flux detection circuit 281 is outside a pre-determined range, the secondary side control circuit 285 stops supplying drive. Specifically, 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 pre-determined second threshold value. Additionally, the second threshold value is a value greater than the first threshold value. When the magnetic flux density indicated by the signal Sig4 is greater than the second threshold value, the secondary side control circuit 285 stops supplying drive. Thereby, it is possible to avoid a failure of the primary side resonance circuit 212 caused by an increase in the electromotive force induced in the primary side coil L1 by the magnetic flux generated in the secondary side coil L2. As described above, outside the pre-determined range means the case where the detection value is greater than the second threshold value.

[0066] In the present embodiment, similarly to the first embodiment, the secondary side control circuit 285 adjusts the drive frequency and duty ratio of the pulse generation circuit 82. However, the secondary side control circuit 85 in the first embodiment adjusts using the detection value of the secondary side voltage sensor M2, whereas the secondary side control circuit 285 in the present embodiment adjusts using the detection value of the magnetic flux detection circuit 281. The closer the distance between the primary side coil L1 and the secondary side coil L2, and the greater the coupling coefficient between the primary side coil L1 and the secondary side coil L2, the greater the detection value of the secondary side voltage sensor M2. Therefore, when the coupling coefficient between the primary side coil L1 and the secondary side coil L2 is greater than a pre-determined threshold value, similarly to the first embodiment, at least one of the drive frequency and duty ratio of the pulse generation circuit 82 is adjusted so that the magnetic flux generated in the secondary side coil L2 does not become too large.

[0067] Specifically, when the secondary side control circuit 285 receives a signal indicating Figure 10 the magnetic flux density detected in step S22 as shown, and the magnetic flux density is equal to or greater than the first threshold value and less than the second threshold value, in Figure 11 step S23 as shown, the coupling coefficient is calculated. The secondary side control circuit 285 calculates the coupling coefficient using a calculation formula pre-stored in the built-in memory.

[0068] Figure 12 The equivalent circuit shown in the upper half of... is an equivalent circuit for deriving the calculation formula of the coupling coefficient. Figure 12 The equivalent circuit shown is an expanded equivalent circuit separately depicting "-L m ". In Figure 12 the lower half of... shows the derivation process of formula (5) for calculating the mutual inductance L m ...

[0069] The current I1 of the primary side coil satisfies Figure 12Formula (1) shown in the lower half. The current I2 in the secondary-side coil satisfies Formula (2). The voltage V of the secondary-side coil when the secondary-side resonant circuit is not in resonance L2 satisfies Formula (3). Substituting the current I2 of Formula (2) into Formula (3), Formula (4) is obtained. Rearranging Formula (4) results in Formula (5). The current I1 in Formula (5) is the current value of the standby current and is known. Since the values of other parameters are also known, by assigning the voltage V of the secondary-side coil L2 , the mutual inductance L m is derived. Then, the coupling coefficient k can be calculated from the value of the mutual inductance L m , the value of the inductance L1 of the primary-side coil, and the value of the inductance L2 of the secondary-side coil. In the present embodiment, a mapping representing the relationship between the detection value of the magnetic flux detection circuit 281 and the voltage VL2 of the secondary-side coil is pre-stored in the memory of the secondary-side control circuit 285. Moreover, the secondary-side control circuit 285 uses this mapping to convert the detection value of the magnetic flux detection circuit 281 into the voltage V of the secondary-side coil L2 and calculates the coupling coefficient k. In addition, the values of the inductances L1 and L2 are also pre-stored in the memory of the secondary-side control circuit 285.

[0070] The secondary-side control circuit 285 changes the drive of the pulse generation circuit 82 according to whether the calculated coupling coefficient k is greater than a predetermined threshold. When step S24 is "No", that is, when the calculated coupling coefficient k is not greater than the predetermined threshold, the secondary-side control circuit 285 drives the pulse generation circuit 82 in step S25a in such a way that the generated magnetic flux becomes the target magnetic flux. On the other hand, when step S24 is "Yes", that is, when the calculated coupling coefficient k is greater than the predetermined threshold, the secondary-side control circuit 285 drives the pulse generation circuit 82 in step S25b in such a way that the generated magnetic flux is less than the target magnetic flux. Specifically, the secondary-side control circuit 285 controls the pulse generation circuit 82 in such a way that the current flowing through the secondary-side coil L2 becomes smaller. Thereby, it is possible to avoid a failure of 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 in 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 conditions.

[0071] 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 generation circuit 82.

[0072] According to the second embodiment described above, the secondary-side control circuit 285 can achieve the same effect as the first embodiment by driving the pulse generation circuit 82 using the magnetic flux detection circuit 281. After the supply drive is performed by the secondary-side control circuit 285, when the detected value of the magnetic flux detection circuit 281 is within the magnetic flux range, that is, when the detected value of the magnetic flux detection circuit 281 is below the first threshold value, the standby drive is continued for a predetermined time or more. Thereby, power consumption of the battery 84 can be suppressed. Further, when the detected value of the magnetic flux detection circuit 281 is outside the range, that is, when the detected value of the magnetic flux detection circuit 281 is greater than the second threshold value, the pulse generation circuit 82 is stopped from supplying an alternating current to the secondary-side coil L2. Thereby, it is possible to avoid a failure of the primary-side resonance circuit 212 due to an increase in the electromotive force induced in the primary-side coil L1 by the magnetic flux generated in the secondary-side coil L2. Further, the secondary-side control circuit 285 performs control to maximize the power supply efficiency using the calculated coupling coefficient k. Thereby, the power supply efficiency in the non-contact power supply system 1 can be optimized.

[0073] C. Third Embodiment: As Figure 13 shown, the circuit configuration of the power transmission device 310 and the circuit configuration of the power reception device 380 in the non-contact power supply system 301 of the present embodiment are different from those of the first embodiment. The same reference numerals are given to the same structures as those in the above-described embodiments, and detailed descriptions are appropriately omitted.

[0074] The structure for changing the impedance of the primary-side resonance circuit 12 in the power transmission device 310 of the present embodiment is different from that of the power transmission device 10 of the first embodiment. The power transmission device 310 includes 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 short-circuits or opens 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.

[0075] When a high-level switching signal Sig5 is input to the second switch SW2, the second switch SW2 becomes in an on state. As a result, one terminal and the other terminal of the capacitor C31 are short-circuited, and the capacitor C31 becomes in a non-conductive state. Here, the capacitance of the capacitor C32 and the inductance of the primary-side coil L1 are set to values that become a resonant state at the operating frequency. Thus, when the second switch SW2 becomes in an on state, a primary-side resonant circuit 312 that is a series resonant circuit is formed by the capacitor C32 and the primary-side coil L1. In contrast, when a low-level switching signal Sig5 is input to the second switch SW2, the second switch SW2 becomes in an off state, and the capacitor C31 becomes in a conductive state. Moreover, since the resonant frequency of the resonant circuit formed by the capacitors C31 and C32 and the primary-side coil L1 deviates from the operating frequency, the primary-side coil L1 becomes in a standby state. In addition, since the combined capacitance value of the capacitors C31 and C32 is smaller than the capacitance value of the capacitor C32, when the second switch SW2 is in an off state, the impedance of the resonant circuit formed by the capacitors C31 and C32 and the primary-side coil L1 with respect to the input AC power becomes large, and the current flowing through the primary-side coil L1 is suppressed.

[0076] The power receiving device 380 of the present embodiment has a current sensor M3 instead of the secondary-side voltage sensor M2, and the current sensor M3 detects the current value flowing through the wiring connected to the positive terminal of the battery 84. The current sensor M3 detects the current value flowing through the pulse generation circuit 82. The current sensor M3 is a current detection circuit that outputs a signal Sig6 indicating the detected current value to the secondary-side control circuit 385.

[0077] In addition, the position of the current sensor M3 can be any one of the wiring N1 connected to the negative terminal of the battery 84 and the wirings N2 and N3 connected to the secondary-side resonant circuit 81 and the pulse generation circuit 82 in addition to the wiring connected to the positive terminal of the battery 84. That is, the current sensor M3 can detect the current value flowing through the pulse generation circuit 82 or the current value flowing through the secondary-side coil L2.

[0078] The power supply start sequence point of the present embodiment is different from that of the first embodiment in that it is a processing step after adding the step S2 of the first embodiment. As Figure 14 shown, after a magnetic flux is generated in the secondary-side coil L2 that is a magnetic flux generation coil (step S2), the secondary-side control circuit 385 determines in step S31 whether the detected value of the current sensor M3 is outside a predetermined range using the signal Sig6.

[0079] Specifically, outside the pre-determined range means the case where the detected current as the detection value is greater than the first threshold Ith1 and the case where it is less than the second threshold Ith2. When the detected current is greater than the first threshold Vth1, for example, a failure such as a wiring break in the secondary-side resonant circuit 81 is assumed. When the detected current is less than the second threshold Ith2, for example, a case where the power transmission device 310 fails to generate magnetic coupling between the primary-side coil L1 and the secondary-side coil L2 is assumed. Therefore, when the detected current is greater than the first threshold Ith1 and less than the second threshold Ith2, the secondary-side control circuit 385 stops supplying drive, and in step S32, an abnormal signal notifying the abnormality is output to the power-receiving side control unit 96( Figure 1 ). When the power-receiving side control unit 96 receives the abnormal signal, for example, it causes a display device (not shown) provided in the vehicle VE to display a message notifying the abnormality. Thus, the occupants in the vehicle VE can know that there is an abnormality in charging. Additionally, when the power-receiving side control unit 96 includes a communication interface capable of communicating with the power transmission device 310, the power-receiving side control unit 96 may also send the abnormality to the power transmission device 310.

[0080] Furthermore, when 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, a resonance shift is assumed. A resonance shift means a state where at least one of the capacitance value and the inductance in the secondary-side resonant circuit 81 deviates from the target value of the capacitance value or the target value of the inductance, so that the resonance frequency of the secondary-side resonant circuit 81 deviates from the operating frequency. Therefore, similar to the first embodiment, the secondary-side control circuit 385 appropriately adjusts the magnetic flux generated by the secondary-side coil L2 by adjusting at least one of the drive frequency and the duty ratio of the pulse generation circuit 82. Specifically, the secondary-side control circuit 385 compares the target current value Itg at a pre-determined drive frequency stored in advance with the detected current value, and performs feedback control so that the detected current value approaches the target current value Itg.

[0081] According to the third embodiment described above, the same effects as those of the above-described respective embodiments are achieved. Additionally, when the detection value is outside the pre-determined range, that is, when the detection value is greater than the first threshold Ith1 and less than the second threshold Ith2, the secondary-side control circuit 385 outputs an abnormal signal to the power-receiving side control unit 96. Thus, the power-receiving side control unit 96 that has received the abnormal signal can perform processing corresponding to the abnormality.

[0082] D. Fourth Embodiment: The secondary-side control circuit 85 of this embodiment performs Figure 15 and Figure 16The abnormality detection process shown is different from the first embodiment in this regard. The same reference numerals are given to the same structures and processing steps as in the above-described embodiments, and the detailed description is appropriately omitted. The secondary-side control circuit 85 repeatedly performs an 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 generation circuit 82 in the non-power receiving state, and detects the voltage value output from the pulse generation circuit 82 in the power receiving state.

[0083] In step S1, the secondary-side control circuit 85 detects the detected portion 14. In step S100, the secondary-side control circuit 85 sets the variables used in this processing routine, that is, the cycle number Nm and the cumulative number Nt, to zero as initial values. The cycle number Nm is a variable for calculating the cycle of the supply drive and the rest drive in the burst drive, that is, Figure 5 the number of the second cycle T2 shown. The cumulative number Nt is a variable for detecting the occurrence of flutter. In addition, in this embodiment, step S2 performed in the first embodiment is omitted.

[0084] In step S102, the secondary-side control circuit 85 increments the cycle number Nm. In step S3, during the drive period Td, the secondary-side control circuit 85 causes the secondary-side coil L2, which is a magnetic flux generation coil, to generate a magnetic flux. In step S104, the secondary-side control circuit 85 starts the rest drive of the pulse generation circuit 82. The secondary-side control circuit 85 measures the elapsed time after starting the rest drive using the built-in timing circuit. During the rest period Tp, when the power transmission device 10 shifts to the power transmission state, the secondary-side control circuit 85 performs Figure 4 the switching process shown, whereby the power receiving device 80 shifts to the power receiving state. In the power receiving state, the secondary-side control circuit 85 performs rectification drive so that the pulse generation circuit 82 functions as a rectifier. Thus, when no abnormality occurs, the detected voltage Vd of the secondary-side voltage sensor M2 becomes the target voltage.

[0085] In step S106, the secondary-side control circuit 85 determines whether the detected voltage Vd of the secondary-side voltage sensor M2 is greater than a predetermined reference voltage Vthd. In this embodiment, it is determined in step S106 whether the power supply of the power transmission device 10 has started. The reference voltage Vthd is less than the target voltage of the output voltage of the pulse generation circuit 82 when the power receiving device 80 receives power. Therefore, when the detected voltage Vd is greater than the reference voltage Vthd, it can be determined that the power receiving device 80 has shifted from the non-power receiving state to the power receiving state.

[0086] In addition, as another method for determining whether the power supply of the power transmission device 10 has started, it can also be determined based on whether the secondary side control circuit 85 switches the driving method of the pulse generation circuit 82 from the standby drive to the rectification drive, that is, whether the switching process has been performed. At this time, when the switching process has been performed, the secondary side control circuit 85 determines that the power supply of the power transmission device 10 has started.

[0087] In step S106, if it is determined that the detected voltage Vd is not greater than the reference voltage Vth, that is, the detected voltage Vd is below the reference voltage Vth, then in step S108, the secondary side control circuit 85 refers to the measurement time of the time-based circuit to determine whether the standby period Tp has elapsed. In step S108, if it is determined that the standby period Tp has not elapsed, then since the power supply from the power transmission device 10 has not started, the secondary side control circuit 85 returns the process to step S106 after a predetermined time has elapsed. The predetermined time is, for example, a few μs.

[0088] In step S108, if it is determined that the standby period Tp has elapsed, then in step S110, which is the first determination process, the secondary side control circuit 85 determines whether the cycle count Nm is equal to or greater than a predetermined reference cycle count Nth1. In addition, in step S108, the case where it is determined that the standby period Tp has elapsed means that the power supply from the power transmission device 10 has not started within the standby period Tp. The reference cycle count Nth1 is an integer of 2 or more, and is "2" in the present embodiment. In step S110, if it is determined that the cycle count Nm is not equal to or greater than the reference cycle count Nth1, that is, the cycle count Nm is less than the reference cycle count Nth1, then the secondary side control circuit 85 returns the process to step S102 after a predetermined time has elapsed. The predetermined time is, for example, a few μs. The process returns to step S102 in order to perform the supply drive and standby drive for the next cycle.

[0089] In step S110, if it is determined that the cycle count Nm is equal to or greater than the reference cycle count Nth1, it is determined that the power transmission device 10 has failed. Therefore, the secondary side control circuit 85 causes the process to enter step S32. Step S32 is performed because although the magnetic flux is generated by the secondary side coil L2 in step S3, the number of cycles Nm in which the power transmission device 10 has not transferred to the power transmission state is equal to or greater than the reference cycle count Nth1. In step S32, the secondary side control circuit 85 performs an output process of outputting an abnormal signal notifying the abnormality to the power reception side control unit 96. As a result, the occupant of the vehicle VE can know that there is an abnormality in the charging. After executing step S32, the secondary side control circuit 85 ends this processing routine.

[0090] As another method, the secondary side control circuit 85 can also perform a stop process of setting the pulse generation circuit 82 to a stop state to replace the processing content of step S32. In addition, the secondary side control circuit 85 can also perform output processing and stop processing. Here, the stop state of the pulse generation circuit 82 refers to a state in which disconnection signals are respectively input to the switching elements Q1 to Q4 of the pulse generation circuit 82. The stop process refers to the process in which the secondary side control circuit 85 outputs disconnection signals to the switching elements Q1 to Q4 respectively. By the secondary side control circuit 85 performing the stop process, power consumption of the battery 84 can be suppressed. The same applies to step S118 described later.

[0091] In step S106, when it is determined that the detected voltage Vd is greater than the reference voltage Vth, the secondary side control circuit 85 Figure 16 In step S112, the cumulative number Nt of times the detected voltage Vd changes from within the power reception range to outside the power reception range is counted during a previously determined detection period. The detection period is, for example, several hundred μs. The inside of the power reception range refers to a range greater than the reference voltage Vthd. The outside of the power reception range refers to a range equal to or lower than the reference voltage Vthd.

[0092] In step S114 where the secondary side control circuit 85 performs a second determination process, it is determined whether the cumulative number Nt is equal to or greater than a reference cumulative number Nth2. The reference cumulative number Nth2 is an integer of 1 or more, and is "1" in the present embodiment. In step S114, if it is determined that the cumulative number Nt is equal to or greater than the reference cumulative number Nth2, it is determined that flutter has occurred due to a failure of the power transmission device 10 or the like. Therefore, in step S118, the secondary side control circuit 85, in the same manner as in step S32, performs output processing of outputting an abnormal signal notifying of an abnormality to the power reception side control unit 96, and ends this processing routine. On the other hand, in step S114, if it is determined 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.

[0093] According to the fourth embodiment described above, when it is determined in step S110 that the cycle number Nm is equal to or greater than the reference cycle number Nth1, the secondary side control circuit 85 performs output processing of outputting an abnormal signal in step S32. Thereby, when the power transmission device 10 fails, the occupants of the vehicle VE can know that an abnormality has occurred. In addition, in step S114, when it is determined that the cumulative number Nt is equal to or greater than the reference cumulative number, output processing is performed in step S118. Thereby, when power reception in the power reception device 80 cannot be performed well due to flutter, the occupants of the vehicle VE can know that there is an abnormality in the power supply.

[0094] E. Other Embodiments: (E1) Fifth Embodiment: Figure 17 In addition to the circuit structure of the first embodiment, the power receiving device 480 of the fifth embodiment shown has an impedance filter 88. The impedance filter 88 is a T-LCL type impedance filter composed of a pair of coils L41, L42 and a capacitor C41. At this time, the secondary side voltage sensor M2 can also be installed at a position where the voltage of the capacitor C41 can be detected.

[0095] (E2) Sixth Embodiment: In Figure 18 In the power receiving device 580 of the sixth embodiment shown, the coil L41 of the impedance filter 88 of the fifth embodiment is omitted. Even if the coil L41 is omitted, the leakage inductance of the secondary side coil L2 can be used as the coil L41 to form the impedance filter 88.

[0096] (E3) Seventh Embodiment: In Figure 19 In the power receiving device 680 of the seventh embodiment shown, it is different from the first embodiment in that it independently includes a magnetic flux generating coil L61 with respect to the secondary side coil L2 and independently includes a rectifier circuit 89 with respect to the pulse generating circuit 82. The rectifier circuit 89 is implemented by a diode bridge. The magnetic flux generating coil L61 is installed at a position where it can be magnetically coupled with the primary side coil L1 together with the secondary side coil L2. The pulse generating circuit 82 receives the supply of DC power from the battery 84. In the structure where the pulse generating circuit 82 is independently included with respect to the rectifier circuit 89, by adjusting the driving frequency and duty ratio of the pulse generating circuit 82, the magnetic flux generated in the primary side coil L1 can be appropriately controlled.

[0097] (E4) In the above first embodiment, the power supplied to the secondary side coil L2 as the magnetic flux generating coil is adjusted by adjusting the driving frequency and duty ratio of the pulse generating circuit 82. In other embodiments, a DC / DC converter may be included 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.

[0098] (E5)In the above-described third embodiment, the detection value of the current sensor M3 is used to drive the pulse generation circuit 82 to eliminate the deviation between the current value flowing through the secondary-side coil L2 and the target current value Itg caused by the resonance shift. At this time, a voltage sensor for detecting the voltage of the secondary-side coil L2 or a voltage sensor for detecting the voltage of the secondary-side capacitor C2 may be provided instead of the current sensor M3. Moreover, the secondary-side control circuit 385 may also use the detection value of this voltage sensor to adjust the drive frequency and duty ratio of the pulse generation circuit 82, thereby replacing the detection value of the current sensor M3.

[0099] (E6)In the above-described first embodiment, in the primary-side resonance circuit 12, the primary-side capacitor C1 is connected in series with the primary-side coil L1, and in the secondary-side resonance circuit 81, the secondary-side capacitor C2 is connected in series with the secondary-side coil L2, which is a so-called S-S type circuit structure. The circuit structures of the primary-side resonance circuit 12 and the secondary-side resonance circuit 81 are not limited to the S-S type. (a) For example, in the primary-side resonance circuit 12, the primary-side capacitor C1 may be connected in parallel with the primary-side coil L1, and in the secondary-side resonance circuit 81, the secondary-side capacitor C2 may be connected in series with the secondary-side coil L2, which is a so-called P-S type circuit structure. (b) Additionally, in addition to the primary-side capacitor C1 connected in series with the primary-side coil L1, a capacitor connected in parallel with the primary-side coil L1 may also be included. In the secondary-side resonance circuit 81, two secondary-side capacitors C2 are respectively connected in series with the two terminals of the secondary-side coil L2, which is a so-called P-SS type circuit structure. (c) Additionally, the primary-side resonance 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 with the secondary-side coil L2 when the primary-side coil L1 and the secondary-side coil L2 are magnetically coupled. (d) Further, the capacitor of the closed circuit may be connected in parallel with the coil instead of in series. (e) Additionally, the primary-side resonance circuit 12 may include a coil connected in series with the primary-side coil L1 and a capacitor connected in parallel with the coil. The coil is arranged at a position where it can be magnetically coupled with the secondary-side coil L2 when the primary-side coil L1 and the secondary-side coil L2 are magnetically coupled.

[0100] (E7)In the above-described first embodiment, the switching elements Q1 to Q4 constituting the pulse generation circuit 82 are implemented by MOSFETs. As another embodiment, the switching elements Q1 to Q4 may also be implemented by other semiconductor elements, such as IGBTs (Insulated Gate Bipolar Transistors) connected with freewheeling diodes.

[0101] (E8) In the above first embodiment, the power receiving side control unit 96 outputs a power supply permission signal or a power supply prohibition signal. Further, when the power supply prohibition signal is input, the secondary side control circuit 85 does not drive the pulse generation circuit 82. In addition to this method, there is also a method in which the power receiving side control unit 96 does not output a power supply permission signal and a power supply prohibition signal. In this case, it may be as follows: when the power supply permission signal is not input, and when the power supply prohibition signal is input, the secondary side control circuit 85 does not drive the pulse generation circuit 82. Thereby, power supply when the battery 84 is not suitable for charging can be avoided.

[0102] (E9) In the above first embodiment, in the non-power receiving state, no current flows through the secondary side coil L2 of the power receiving device 80. As another embodiment, in the non-power receiving state, a current may flow through the secondary side coil L2 of the power receiving device 80, and in step S3, the secondary side control circuit 85 increases the current flowing through the secondary side coil L2, thereby increasing the magnetic flux linked to and radiated from the primary side coil L1.

[0103] The present disclosure is not limited to the above embodiments and modifications, and can be implemented by various structures without exceeding the above gist. For example, the technical features in the respective embodiments and modifications corresponding to the technical features in the respective modes described in the summary of the invention can be appropriately replaced or combined to solve part or all of the above technical problems, or to achieve part or all of the above effects. In addition, the above technical features can be appropriately deleted as long as they are not described as essential structures in this specification.

[0104] Although the present disclosure has been described based on the embodiments, it should be understood that the present disclosure is not limited to the above embodiments and structures. The present disclosure also includes various modifications and modifications within the equivalent scope. In addition, various combinations and modes, and further other combinations and modes including only one element, more than one or less than one thereof also belong to the scope and ideological scope of the present disclosure.

[0105] Other methods: The features of the present disclosure are as follows. (Mode 1) A non-contact power supply system (1, 201, 301) that supplies power to a power receiving device (80, 280, 380) from a power transmission device (10, 210, 310) in a non-contact manner. The power transmission device has: A primary side resonance circuit (12) having a primary side coil (L1) and a primary side capacitor (C1); An AC power supply (11) that applies AC power of a predetermined operating frequency to the primary side resonance circuit, and A primary - side detection circuit (120) for detecting the magnitude of the magnetic flux linked to the primary - side coil or the magnitude of the magnetic flux near the primary - side coil. The power - receiving device includes: A secondary - side resonance 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 generation circuit (86, 286, 386) having: a magnetic - flux generation coil (L2) for generating magnetic flux radiated to the primary - side coil in the standby state of the power - transmitting device; a pulse generation circuit (82) for supplying AC power to the magnetic - flux generation coil; and a secondary - side control circuit (85, 285, 385) for controlling the pulse generation circuit; and A secondary - side detection circuit (M2, 281, M3) for detecting at least any one of the voltage value supplied to the pulse generation circuit, the current value flowing through the secondary - side coil or the pulse generation circuit, and the magnitude of the magnetic flux generated from the primary - side coil. When the power - transmitting device detects an increase in the magnetic flux linked to the primary - side coil or the magnetic flux near the primary - side coil through the primary - side detection circuit, it transfers from the standby state to a power - transmission state in which a power - transmission current flows through the primary - side coil. The magnetic - flux generation circuit adjusts the generated magnetic flux using the detection value of the secondary - side detection circuit. (Mode 2) In the non - contact power - supply system described in Mode 1, The power - receiving device further includes a battery (84) for supplying DC power to the pulse generation circuit. The secondary - side detection circuit is a voltage detection circuit that detects the output voltage value of the battery as the voltage value supplied to the pulse generation circuit. (Mode 3) In the non - contact power - supply system described in Mode 2, The pulse generation circuit is configured as an inverter. The secondary - side control circuit adjusts the generated magnetic flux by adjusting at least any one of the drive frequency and the duty ratio of the pulse generation circuit. (Mode 4) In the non - contact power - supply system described in Mode 2 or 3, When the detection value is outside a predetermined range, the secondary - side control circuit stops the supply of AC power to the pulse generation circuit. (Mode 5) In the non - contact power - supply system according to any one of Modes 2 to 3, When in the non-powered state, the secondary-side control circuit periodically repeats supply driving and standby driving. The supply driving is to supply alternating current power from the pulse generation circuit to the magnetic flux generation coil, and the standby driving is to stop the pulse generation circuit from supplying alternating current power to the magnetic flux generation coil. After the power transmission device detects an increase in the magnetic flux linked to the primary-side coil or the magnetic flux near the primary-side coil by the primary-side detection circuit, after a predetermined standby time for transitioning to the power transmission state has elapsed during the standby driving, it transitions to the power transmission state. (Mode 6) In the non-contact power supply system according to any one of Modes 1 to 5, The secondary-side detection circuit is a magnetic flux detection circuit that detects the magnitude of the magnetic flux generated by the primary-side coil. (Mode 7) In the non-contact power supply system described in Mode 6, The pulse generation circuit is configured as an inverter. The secondary-side control circuit adjusts the generated magnetic flux by adjusting at least one of the driving frequency and the duty ratio of the pulse generation circuit. (Mode 8) In the non-contact power supply system described in Mode 6 or 7, When the detected value is outside a predetermined range, the secondary-side control circuit stops the supply of alternating current to the pulse generation circuit. (Mode 9) In the non-contact power supply system according to any one of Modes 6 to 8, The secondary-side control circuit periodically repeats supply driving and standby driving. The supply driving is to supply alternating current power from the pulse generation circuit to the magnetic flux generation coil, and the standby driving is to stop the pulse generation circuit from supplying alternating current power to the magnetic flux generation coil. After performing the supply driving, when the detected value is within a predetermined magnetic flux range, the standby driving is continued for a predetermined time or more. (Mode 10) In the non-contact power supply system according to any one of Modes 6 to 9, The secondary-side control circuit controls the power supply efficiency to be maximum using the coupling coefficient calculated from the detected value. (Mode 11) In the non-contact power supply system according to any one of Modes 1 to 10, The secondary-side detection circuit is a current detection circuit that detects the current value flowing through the secondary-side coil or the pulse generation circuit. (Mode 12) In the contactless power supply system described in Mode 11, The pulse generation circuit is configured as an inverter, The secondary side control circuit uses the detection value when driving the pulse generation circuit under predetermined conditions to adjust at least one of the driving frequency and duty ratio of the pulse generation circuit, thereby adjusting the generated magnetic flux. (Mode 13) In the contactless power supply system described in Mode 11 or 12, When the detection value is outside a predetermined range, the secondary side control circuit outputs an abnormal signal. (Mode 14) In the contactless power supply system according to any one of Modes 1 to 13, When the secondary side control circuit receives a power supply prohibition signal, or when it does not receive the power supply prohibition signal and the power supply permission signal, it sets the pulse generation circuit to a stopped state. (Mode 15) In the contactless power supply system described in Mode 14, After the secondary side control circuit receives the power supply prohibition signal, when it receives the power supply permission signal, it starts driving the pulse generation circuit. (Mode 16) In the contactless power supply system described in Mode 5, The power receiving device is installed on a moving body (VE), The secondary side control circuit adjusts the period of the rest drive using the moving speed acquired by a speed acquisition unit (97) that acquires the moving speed of the moving body. (Mode 17) In the contactless power supply system described in Mode 1, The power receiving device further has a battery (84) that supplies DC power to the pulse generation circuit, The pulse generation circuit functions as an inverter that converts the DC power supplied from the battery into AC power in a non-power receiving state, and functions as a rectifier that converts the AC power output from the secondary side resonance circuit into DC power in a power receiving state. In the non-powered state, the secondary-side control circuit periodically repeats supply driving and rest driving. The supply driving is to supply AC power from the pulse generation circuit to the magnetic flux generation coil during a predetermined driving period, and the rest driving is to stop the pulse generation circuit from supplying AC power to the magnetic flux generation coil during a predetermined rest period after the supply driving. The secondary-side control circuit performs switching processing and first determination processing. The switching processing is to switch from the rest driving to rectification driving in which the pulse generation circuit functions as a rectifier when power supply starts from the power transmission device during the rest period. The first determination processing is to determine whether the number of cycles of the supply driving and the rest driving is equal to or greater than a predetermined reference number of cycles when power supply does not start from the power transmission device during the rest period after the rest period ends. In the first determination processing, when it is determined that the number of cycles is equal to or greater than the reference number of cycles, at least one of output processing for outputting an abnormal signal and stop processing for setting the pulse generation circuit to a stopped state is performed. (Mode 18) In the non-contact power supply system described in Mode 1, The power receiving device further includes a battery (84) that supplies DC power to the pulse generation circuit. The secondary-side detection circuit that detects the voltage value supplied to the pulse generation circuit detects the voltage value supplied to the pulse generation circuit and the voltage value output from the pulse generation circuit. In the non-powered state, the pulse generation circuit functions as an inverter that converts the DC power supplied from the battery into AC power, and in the powered state, functions as a rectifier that converts the AC power output from the secondary-side resonance circuit into DC power. In the non-powered state, the secondary-side control circuit periodically repeats supply driving and rest driving. The supply driving is to supply AC power from the pulse generation circuit to the magnetic flux generation coil during a predetermined driving period, and the rest driving is to stop the pulse generation circuit from supplying AC power to the magnetic flux generation coil during a predetermined rest period after the supply driving. The secondary-side control circuit performs switching processing and second determination processing. The switching processing is to switch from the rest driving to rectification driving in which the pulse generation circuit functions as a rectifier when power supply starts from the power transmission device during the rest period. The second determination process is to determine, during the rectification drive, whether the cumulative number of times the detected value changes from within a predetermined power reception range to outside the power reception range within a predetermined detection period is equal to or greater than a predetermined reference cumulative number. In the second determination process, when it is determined that the cumulative number is equal to or greater than the reference cumulative number, at least one of an output process of outputting an abnormal signal and a stop process of setting the pulse generation circuit to a stopped state is performed. (Mode 19) In the non-contact power supply system described in Mode 1, The secondary side coil is used as the magnetic flux generation coil. The power receiving device further includes a battery (84) that supplies DC power to the pulse generation circuit. The pulse generation circuit is a synchronous rectification circuit that functions as an inverter that converts DC power supplied from the battery into AC power in a non-power reception state, and functions as a rectifier that converts AC power output from the secondary side resonance circuit into DC power in a power reception state. The battery supplies DC power to the pulse generation circuit in the non-power reception state and stores the DC power output from the secondary side resonance circuit in the power reception state. (Mode 20) A power receiving device (80, 280, 380) that is powered in a non-contact manner from a power transmitting device (10, 210, 310). The power transmitting device includes: A primary side resonance circuit (12) having a primary side coil (L1) and a primary side capacitor (C1); An AC power supply (11) that applies AC power of a predetermined operating frequency to the primary side resonance circuit; and A primary side detection circuit (120) that detects the magnitude of the magnetic flux linked to the primary side coil or the magnitude of the magnetic flux near the primary side coil. The power receiving device includes: A secondary side resonance circuit (81) having a secondary side coil (L2) for magnetic coupling with the primary side coil and a secondary side capacitor (C2); A magnetic flux generation circuit (86, 286, 386) having: a magnetic flux generation coil (L2) that generates magnetic flux radiated to the primary side coil in the standby state of the power transmitting device; a pulse generation circuit (82) that supplies AC power to the magnetic flux generation coil; and a secondary side control circuit (85, 285, 385) that controls the pulse generation circuit. A secondary-side detection circuit (M2, 281, M3) 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 or the pulse generation circuit, and a magnitude of a magnetic flux generated from the primary-side coil. When the power transmission device detects an increase in the magnetic flux linked to the primary-side coil or the magnetic flux near the primary-side coil through the primary-side detection circuit, it transfers from the standby state to a power transmission state in which a power transmission current flows through the primary-side coil. The magnetic flux generation circuit adjusts the generated magnetic flux using the detection value of the secondary-side detection circuit. (Mode 21) A power transmission device (10, 210, 310) that supplies power to a power receiving device (80, 280, 380) in a non-contact manner. The power transmission device includes: A primary-side resonance circuit (12) having a primary-side coil (L1) and a primary-side capacitor (C1); An AC power supply (11) that applies AC power of a predetermined operating frequency to the primary-side resonance circuit; and A primary-side detection circuit (120) that detects the magnitude of the magnetic flux linked to the primary-side coil or the magnitude of the magnetic flux near the primary-side coil. The power receiving device includes: A secondary-side resonance circuit (81) having a secondary-side coil (L2) for magnetic coupling with the primary-side coil and a secondary-side capacitor (C2); A magnetic flux generation circuit (86, 286, 386) having: a magnetic flux generation coil (L2) that generates a magnetic flux radiated toward the primary-side coil in the standby state of the power transmission device; a pulse generation circuit (82) that supplies AC power to the magnetic flux generation coil; and a secondary-side control circuit (85, 285, 385) that controls the pulse generation circuit; and A secondary-side detection circuit (M2, 281, M3) 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 or the pulse generation circuit, and a magnitude of a magnetic flux generated from the primary-side coil. The magnetic flux generation circuit adjusts the generated magnetic flux using the detection value of the secondary-side detection circuit. When the power transmission device detects an increase in the magnetic flux linked to the primary-side coil or the magnetic flux near the primary-side coil through the primary-side detection circuit, it transfers from the standby state to a power transmission state in which a power transmission current flows through the primary-side coil.

Claims

1. A non-contact power supply system is a non-contact power supply system (1, 201, 301) that supplies power from a power transmission device (10, 210, 310) to a power reception device (80, 280, 380) in a non-contact manner. The power transmission device has: A primary-side resonance circuit (12) having a primary-side coil (L1) and a primary-side capacitor (C1); An AC power supply (11) that applies AC power of a predetermined operating frequency to the primary-side resonance circuit, and A primary-side detection circuit (120) that detects the magnitude of the magnetic flux linked to the primary-side coil or the magnitude of the magnetic flux near the primary-side coil. The power reception device has: A secondary-side resonance circuit (81) having a secondary-side coil (L2) for magnetic coupling with the primary-side coil and a secondary-side capacitor (C2); A magnetic flux generation circuit (86, 286, 386) having a magnetic flux generation coil (L2), a pulse generation circuit (82), and a secondary-side control circuit (85, 285, 385). The magnetic flux generation coil is used to generate a magnetic flux radiated to the primary-side coil in the standby state of the power transmission device. The pulse generation circuit supplies AC power to the magnetic flux generation coil, and the secondary-side control circuit controls the pulse generation circuit; and A secondary-side detection circuit (M2, 281, M3) that detects at least any one of the voltage value supplied to the pulse generation circuit, the current value flowing through the secondary-side coil or the pulse generation circuit, and the magnitude of the magnetic flux generated from the primary-side coil. When the power transmission device detects an increase in the magnetic flux linked to the primary-side coil or the magnetic flux near the primary-side coil through the primary-side detection circuit, it transfers from the standby state to a power transmission state in which a power transmission current flows through the primary-side coil. The magnetic flux generation circuit adjusts the generated magnetic flux using the detection value of the secondary-side detection circuit.

2. The non-contact power supply system according to claim 1, wherein The power reception device further has a battery (84) that supplies DC power to the pulse generation circuit. The secondary-side detection circuit is a voltage detection circuit that detects the output voltage value of the battery as the voltage value supplied to the pulse generation circuit.

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

4. The non-contact power supply system according to claim 2 or 3, wherein When the detection value is outside a predetermined range, the secondary-side control circuit stops the supply of AC power to the pulse generation circuit.

5. The non-contact power supply system according to claim 3, wherein In a non-powered state, the secondary-side control circuit periodically repeats supply driving and rest driving. The supply driving is to supply alternating current power from the pulse generation circuit to the magnetic flux generation coil, and the rest driving is to stop the pulse generation circuit from supplying alternating current power to the magnetic flux generation coil. After the power transmission device detects an increase in the magnetic flux linked to the primary-side coil or the magnetic flux near the primary-side coil by the primary-side detection circuit, after a predetermined standby time for transitioning to the power transmission state has elapsed during the rest driving, it transitions to the power transmission state.

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

7. The contactless power supply system according to claim 6, wherein: The pulse generation circuit is configured as an inverter. The secondary-side control circuit adjusts the generated magnetic flux by adjusting at least one of the driving frequency and the duty ratio of the pulse generation circuit.

8. The contactless power supply system according to claim 6 or 7, wherein: When the detected value is outside a predetermined range, the secondary-side control circuit stops the supply of alternating current of the pulse generation circuit.

9. The contactless power supply system according to claim 7, wherein: The secondary-side control circuit periodically repeats supply driving and rest driving. The supply driving is to supply alternating current power from the pulse generation circuit to the magnetic flux generation coil, and the rest driving is to stop the pulse generation circuit from supplying alternating current power to the magnetic flux generation coil. After performing the supply driving, when the detected value is within a predetermined magnetic flux range, the rest driving is continued for a predetermined time or more.

10. The contactless power supply system according to claim 6, wherein: The secondary-side control circuit uses the coupling coefficient calculated from the detected value to perform control in a manner that maximizes the power supply efficiency.

11. The contactless power supply system according to claim 1, wherein: The secondary-side detection circuit is a current detection circuit that detects the current value flowing through the secondary-side coil or the pulse generation circuit.

12. The contactless power supply system according to claim 11, wherein: The pulse generation circuit is configured as an inverter. The secondary-side control circuit uses the detected value when driving the pulse generation circuit under predetermined conditions to adjust at least one of the driving frequency and the duty ratio of the pulse generation circuit, thereby adjusting the generated magnetic flux.

13. The contactless power supply system according to claim 11 or 12, wherein: When the detected value is outside a predetermined range, the secondary-side control circuit outputs an abnormal signal.

14. The contactless power supply system according to claim 1, wherein: When the secondary - side control circuit receives a power - supply prohibition signal, or when it receives neither the power - supply prohibition signal nor the power - supply permission signal, the pulse generation circuit is set to a stopped state.

15. The non - contact power - supply system according to claim 14, wherein After the secondary - side control circuit receives the power - supply prohibition signal, when it receives the power - supply permission signal, it starts driving the pulse generation circuit.

16. The non - contact power - supply system according to claim 5, wherein The power - receiving device is installed on a moving body (VE), The secondary - side control circuit adjusts the period of the rest drive by using the moving speed acquired by a speed acquisition unit (97) that acquires the moving speed of the moving body.

17. The non - contact power - supply system according to claim 1, wherein The power - receiving device further has a battery (84) that supplies DC power to the pulse generation circuit, The pulse generation circuit functions as an inverter that converts the DC power supplied from the battery into AC power in a non - power - receiving state, and functions as a rectifier that converts the AC power output from the secondary - side resonance circuit into DC power in a power - receiving state. In the non - power - receiving state, the secondary - side control circuit periodically repeats supply drive and rest drive. The supply drive is to supply AC power from the pulse generation circuit to the magnetic - flux generation coil during a predetermined drive period, and the rest drive is to stop the pulse generation circuit from supplying AC power to the magnetic - flux generation coil during a predetermined rest period after the supply drive. The secondary - side control circuit performs a switching process and a first determination process. The switching process is, during the rest period, when power supply starts from the power - transmitting device, to switch from the rest drive to a rectification drive in which the pulse generation circuit functions as a rectifier. The first determination process is, after the rest period ends, when power supply does not start from the power - transmitting device during the rest period, to determine whether the number of cycles of the supply drive and the rest drive is equal to or greater than a predetermined reference number of cycles. In the first determination process, when it is determined that the number of cycles is equal to or greater than the reference number of cycles, at least one of an output process for outputting an abnormal signal and a stop process for setting the pulse generation circuit to a stopped state is performed.

18. The non - contact power - supply system according to claim 1, wherein The power - receiving device further has a battery (84) that supplies DC power to the pulse generation circuit, The secondary - side detection circuit that detects the voltage value supplied to the pulse generation circuit detects the voltage value supplied to the pulse generation circuit and the voltage value output from the pulse generation circuit. The pulse generation circuit functions as an inverter that converts the DC power supplied from the battery into AC power in a non - power - receiving state, and functions as a rectifier that converts the AC power output from the secondary - side resonance circuit into DC power in a power - receiving state. The secondary - side control circuit periodically repeats supply driving and rest driving in the non - power - receiving state. The supply driving is to supply AC power from the pulse generation circuit to the magnetic - flux generation coil during a predetermined driving period, and the rest driving is to stop the pulse generation circuit from supplying AC power to the magnetic - flux generation coil during a predetermined rest period after the supply driving. The secondary - side control circuit performs switching processing and second determination processing. The switching processing is, during the rest period, when power supply starts from the power - transmitting device, to switch from the rest driving to rectification driving in which the pulse generation circuit functions as a rectifier. The second determination processing, during the rectification driving, determines whether the cumulative number of times the detected value changes from within a predetermined power - receiving range to outside the power - receiving range within a predetermined detection period is equal to or more than a predetermined reference cumulative number. In the second determination processing, when it is determined that the cumulative number is equal to or more than the reference cumulative number, at least one of output processing for outputting an abnormal signal and stop processing for setting the pulse generation circuit to a stop state is performed.

19. The non - contact power - supply system according to claim 1, wherein: The secondary - side coil is used as the magnetic - flux generation coil. The power - receiving device further has a battery (84) that supplies DC power to the pulse generation circuit. The pulse generation circuit is a synchronous rectification circuit, which functions as an inverter that converts DC power supplied from the battery into AC power in the non - power - receiving state, and functions as a rectifier that converts AC power output from the secondary - side resonant circuit into DC power in the power - receiving state. The battery supplies DC power to the pulse generation 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 is powered in a non - contact manner from a power - transmitting device (10, 210, 310). The power - transmitting device has: 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) that detects the magnitude of the magnetic flux linked to the primary - side coil or the magnitude of the magnetic flux near the primary - side coil. The power - receiving device has: A secondary - side resonant circuit (81) having a secondary - side coil (L2) for magnetic coupling with the primary - side coil and a secondary - side capacitor (C2). A magnetic flux generation circuit (86, 286, 386) having a magnetic flux generation coil (L2), a pulse generation circuit (82), and a secondary side control circuit (85, 285, 385), the magnetic flux generation coil being configured to generate a magnetic flux radiated toward the primary side coil in a standby state of the power transmission device, the pulse generation circuit supplying alternating current power to the magnetic flux generation coil, and the secondary side control circuit controlling the pulse generation circuit; and A secondary side detection circuit (M2, 281, M3) 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 or the pulse generation circuit, and a magnitude of a magnetic flux generated from the primary side coil, When the power transmission device detects an increase in the magnetic flux linked to the primary side coil or the magnetic flux near the primary side coil through the primary side detection circuit, it transfers from the standby state to a power transmission state in which a power transmission current flows through the primary side coil, The magnetic flux generation circuit adjusts the generated magnetic flux using the detection value of the secondary side detection circuit.

21. A power transmission device (10, 210, 310) that supplies power to a power reception device (80, 280, 380) in a non-contact manner, The power transmission device has: A primary side resonance circuit (12) having a primary side coil (L1) and a primary side capacitor (C1); An AC power supply (11) that applies AC power at a predetermined operating frequency to the primary side resonance circuit, and A primary side detection circuit (120) for detecting the magnitude of the magnetic flux linked to the primary side coil or the magnitude of the magnetic flux near the primary side coil, The power reception device has: A secondary side resonance circuit (81) having a secondary side coil (L2) for magnetic coupling with the primary side coil and a secondary side capacitor (C2); A magnetic flux generation circuit (86, 286, 386) having a magnetic flux generation coil (L2), a pulse generation circuit (82), and a secondary side control circuit (85, 285, 385), the magnetic flux generation coil being configured to generate a magnetic flux radiated toward the primary side coil in a standby state of the power transmission device, the pulse generation circuit supplying alternating current power to the magnetic flux generation coil, and the secondary side control circuit controlling the pulse generation circuit; and A secondary side detection circuit (M2, 281, M3) 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 or the pulse generation circuit, and a magnitude of a magnetic flux generated from the primary side coil, The magnetic flux generation circuit adjusts the generated magnetic flux using the detection value of the secondary side detection circuit, When the power transmission device detects an increase in the magnetic flux linked to the primary side coil or the magnetic flux near the primary side coil through the primary side detection circuit, it transfers from the standby state to a power transmission state in which a power transmission current flows through the primary side coil.

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