Non-contact power transmission device, non-contact power transmission method, and non-contact power supply system

Abstract

Power is supplied by resonance from a power transmission device (50) to a power reception coil (31) side that is magnetically coupled to a power transmission coil (51). In this case, even if the resonance circuit (53) is operated in a state in which the magnetic fields of the power transmission coil and the power reception coil are not coupled, an overcurrent is prevented from flowing through the resonance circuit. A power transmission device supplies AC power from a main power supply device (70) to a resonance circuit including a power transmission coil magnetically coupled to a power reception coil provided in a power reception device (30) via power lines (NL1, NL2), and the resonance circuit is brought into a resonance state in a state in which the power reception coil is close to the power transmission coil. The resonance circuit is set to a non-resonance state in a state in which the power reception coil is not close to the power transmission coil. On this basis, when an abnormality related to the supply of power to the power receiving device is detected, the power line is switched to a non-conductive state, and the supply of AC power from the main power supply device to the resonance circuit is cut off.

Description

Citation of related applications

[0001] This application is based on patent application No. 2022-139140 filed in Japan on September 1, 2022, and claims the priority thereof. The entire contents of the patent application will be incorporated into this specification by reference. Technical Field

[0002] The present disclosure relates to a technology for transmitting or supplying electricity in a contactless manner. Background Art

[0003] Various technologies for transmitting or supplying power to the power supply object have been proposed. The power supply object is not necessarily a moving object, but in order to take advantage of the contactless power supply, as shown in Japanese Patent Publication No. 2017-51074, there are many proposals for technologies for supplying power to the moving object in a contactless manner. As shown in Japanese Patent Publication No. 2017-51074, a structure using magnetic field coupling, especially magnetic field coupling using resonance, is proposed in this contactless power supply. In Japanese Patent Publication No. 2017-51074, in order to energize the power transmission coil that can be magnetically coupled with the power receiving coil on the power receiving side, a switch is set to turn on / off the power transmission.

[0004] However, in the contactless power supply using such a resonant circuit, if some abnormality occurs, for example, when there is no receiving-side device, that is, when there is no object for magnetic field coupling, and the power transmitting side remains in operation, a large current may flow through the resonant circuit on the power transmitting side, causing a fault. Such a fault may be caused by various factors such as the presence of the receiving-side device being erroneously detected or a malfunction of the power transmitting-side device. If a large current flows through the resonant circuit on the power transmitting side, a malfunction may occur, such as a malfunction of the main power supply device that supplies power to the power transmitting device. Summary of the invention

[0005] [1] One embodiment of the present disclosure is a method of a power transmission device that receives power supply from a main power supply device and transmits power to a power receiving device provided at a power supply target in a non-contact manner. The non-contact power transmission device includes: a resonant circuit having a power transmission coil that is magnetically coupled to a power receiving coil provided at the power receiving device; an abnormality detection unit that detects an abnormality related to power supply to the power receiving device; a disconnection unit that is provided on a power line that supplies AC power from the main power supply device to the resonant circuit and is capable of switching the power line to a non-conductive state; and a control unit that, when the abnormality is detected by the abnormality detection unit, activates the disconnection unit to stop the power supply from the main power supply device to the resonant circuit.

[0006] [2] Another embodiment of the present disclosure is a method for transmitting power to a power receiving device provided at a power supply target in a non-contact manner. The non-contact power transmission method supplies AC power from a main power supply device via a power line to a resonant circuit having a power transmission coil that is magnetically coupled to a power receiving coil provided at the power receiving device, sets the resonant circuit to a resonant state when the power receiving coil is close to the power transmission coil, and sets the resonant circuit to a non-resonant state when the power receiving coil is not close to the power transmission coil, and when an abnormality related to power supply to the power receiving device is detected, switches the power line to a non-conductive state, and cuts off the supply of the AC power from the main power supply device to the resonant circuit.

[0007] [3] Another aspect of the present disclosure is an aspect of a power supply system including a main power supply device, a power transmission device, and a power receiving device, wherein the power transmission device operates by receiving power supplied from the main power supply device, and the power receiving device receives power from the power transmission device in a non-contact manner. The power receiving device of the non-contact power supply system includes: a power receiving side resonance circuit, the power receiving side resonance circuit including a power receiving coil; a rectifier circuit, the rectifier circuit rectifies the alternating current induced in the power receiving side resonance circuit to extract direct current power; and a load device, the load device operates using the direct current power. On the other hand, the power transmission device of the contactless power supply system includes: a power transmission side resonance circuit, the power transmission side resonance circuit has a power transmission coil coupled with the magnetic field of the power receiving coil; a cut-off unit, the cut-off unit is provided on a power line that supplies power from the main power supply device to the power transmission side resonance circuit, and can switch the power line to a non-conductive state; an abnormality detection unit, the abnormality detection unit detects an abnormality related to the power supply to the power receiving device; and a control unit, the control unit operates the cut-off unit to cut off the power supply to the power transmission side resonance circuit when the abnormality is detected by the abnormality detection unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The above objects, other objects, features and advantages of the present disclosure will become more apparent with reference to the accompanying drawings and the following detailed description. Figure 1 It is a schematic configuration diagram of a contactless power supply system including a power receiving device according to an embodiment. Figure 2 This is a block diagram illustrating the configuration of a main power supply device. Figure 3 It is an explanatory diagram showing a schematic configuration of a power transmitting device and a power receiving device. Figure 4 This is a schematic structural diagram of a power transmission device. Figure 51 is a circuit configuration diagram showing a configuration example of a DC power supply unit of a power transmitting device and a second power supply unit of a power receiving device. Figure 6 : is a circuit configuration diagram showing a detailed configuration of the power transmission device. Figure 7 This is a flowchart showing an overview of the processing executed by the control unit. Fig. 8A It is a circuit configuration diagram of a power transmission device according to a second embodiment. Figure 8B It is an explanatory diagram showing the operating states of the switching unit and the power transmission device. Figure 8C It is a circuit configuration diagram showing a modification of the second embodiment. Fig. 9 It is a circuit configuration diagram of a power transmission device according to a third embodiment. Fig.10 It is a circuit configuration diagram of a power transmission device according to a fourth embodiment. Fig.11A It is a circuit configuration diagram of a power transmission device having a relay circuit according to a fifth embodiment. Fig. 11B It is an explanatory diagram showing the operating states of the switching unit and the power transmission device. Fig.12 It is a circuit configuration diagram of a power transmission device having a relay circuit according to a sixth embodiment. Fig.13 It is a circuit configuration diagram of a power transmission device having a relay circuit according to a seventh embodiment. Fig.14 It is a circuit configuration diagram of a power transmission device as a modification of the seventh embodiment. Fig.15 It is a circuit configuration diagram of a power transmission device according to an eighth embodiment. Fig.16 It is an explanatory diagram showing the operating states of the switching unit and the power transmission device. Fig.17 It is a circuit configuration diagram of a power transmission device as a modification of the eighth embodiment. DETAILED DESCRIPTION

[0009] A. First Implementation Method: (A1) Overall structure of the contactless power supply system: Figure 1The schematic structure of a contactless power supply system 100 including a power transmission device 50 of the first embodiment is shown. As shown in the figure, the contactless power supply system 100 is composed of a plurality of power transmission devices 50 buried in the soil under the road surface RS and a power receiving device 30 installed on a moving body 20 that automatically travels on the road surface RS. The moving body 20 includes a driving wheel 21 driven by an unillustrated motor included in the load device 45, a driven wheel 22 that supports the moving body 20 together with the driving wheel 21 so that it can move on the road surface RS, a power receiving coil 31 arranged under the bottom plate of the moving body 20, and a magnet 24 similarly arranged under the bottom plate. The power receiving coil 31 receives the supply of AC power by magnetic field coupling with the power transmission coil 51 of the power transmission device 50 prepared on the road surface RS side, and supplies power to the load device 45. In addition, the power transmission device 50 and the contactless power supply system 100 including the power transmission device 50 are not limited to a system that supplies power to the power receiving device 30 of the mobile body 20. As long as they are a device and a system that transmits power and supplies power in a contactless manner, the power receiving device may also be a device and a system that transmits power and supplies power to a device that is not a mobile body, such as a portable terminal.

[0010] In addition to the structure buried under the road surface RS, the power transmission device 50 can also be installed on the road surface or on the wall or ceiling. In this case, the power receiving device 30 can be arranged at a predetermined position in the moving body 20 corresponding to the installation position of the power transmission device 50. For example, if the power transmission device 50 is laid on the wall, the power receiving device 30 can be arranged on the side of the moving body 20. In addition, the power receiving device 30 can be moved inside the moving body 20 in coordination with the installation position of the power transmission device 50, or a plurality of power receiving devices 30 can be prepared in advance and switched for use. The plurality of power transmission devices 50 that supply power to the power receiving device 30 of the mobile body 20 respectively include the same structure and are arranged along the moving path of the mobile body 20. Of course, the power transmission devices 50 are not limited to the moving path of the mobile body 20, and can also be arranged two-dimensionally on the road surface RS. Each power transmission device 50 is connected to a common main power line RFP. High-frequency (e.g., 85KHz) AC power is supplied from the main power supply device 70 to the main power line RFP. In the present embodiment, each power transmission device 50 has the same structure, but, for example, power transmission coils 51 of different sizes may be alternately configured, and as long as power can be transmitted, it does not matter if the structures are different. Of course, the power transmission device 50 may also be one.

[0012] The main power supply device 70 receives a supply of low-frequency (eg, 60 Hz) alternating current from the main power supply 90 , and converts the supply into high-frequency alternating current. Figure 2FIG. 1 shows an example of a circuit configuration of a main power supply device 70. The main power supply device 70 includes a noise filter 71, a PFC circuit 72, an inverter 73, and a filter 74 for AC output on the side receiving power from the main power supply 90. The PFC circuit 72 is a well-known circuit that improves the power factor by eliminating the phase difference between the input voltage and the output current generated by the filter 71, suppressing high-frequency harmonics, and making the power factor close to 1. The power supplied from the main power supply 90 is converted into an AC of the above frequency by the inverter 73 and output to the main power line RFP.

[0013] Figure 3 The schematic configuration of a power transmission device 50 and a power receiving device 30 is shown. The figure shows a state in which one of the plurality of power transmission devices 50 supplies power to the power receiving device 30 of the mobile body 20. At this time, the power transmission coil 51 of the power transmission device 50 is magnetically coupled with the power receiving coil 31 of the power receiving device 30, and an induced current (AC) flows in the power receiving coil 31. The power receiving device 30 includes a first power supply unit 41, a second power supply unit 42, a control circuit 43, and a load device 45. The power receiving coil 31 efficiently receives power through the power receiving side resonant circuit 33 included in the first power supply unit 41. A rectifier circuit 34 is provided at the subsequent stage of the power receiving side resonant circuit 33, and the power received by the power receiving coil 31 is converted into a DC and output to the load device 45. Here, the load device 45 refers to all devices that use the power output by the first power supply unit 41, but in the case of the mobile body 20, it includes devices that use the main power used in the mobile body, such as the motor 48 for moving the mobile body 20. In addition, a battery that temporarily stores power may also be included in the load device 45.

[0014] The second power supply unit 42 is a circuit that generates a small DC power separately from the first power supply unit 41, and operates by receiving power supply from both ends of the power receiving coil 31, that is, from a position in the previous stage of the power receiving side resonance circuit 33. The DC voltage output by the second power supply unit 42 is used in the control circuit 43 and the like. The structure of the second power supply unit 42 and the specific circuit structure of the control circuit 43 will be summarized and described later. In addition, the power supply for the control circuit 43 can also be supplied from the load device 45 side.

[0015] Next, use Figure 4The circuit structure of the power transmission device 50 is described below. In the figure, the power transmission coil 51 and the resonance circuit 53 are shown separately, but the power transmission coil 51 is included in the resonance circuit 53 composed of the resonance capacitor C. A cut-off unit 55 is installed between the resonance circuit 53 and the main power line RFP. The cut-off unit 55 is a circuit that cuts off the supply of high-frequency power from the main power line RFP to the resonance circuit as needed. Equivalently, in this embodiment, it is a fuse, a relay, a switching element, etc. that cuts off the supply of high-frequency power. Each power transmission device 50 also includes a control unit 65 that controls the cut-off unit 55, an abnormality detector 61 that detects abnormalities such as overheating or abnormal current of the power transmission device 50, a proximity sensor 62 that detects the presence of the moving body 20, and a DC power supply unit 60 that supplies working DC power to the control unit 65.

[0016] The operation of the power transmission device 50 using the control unit 65 and the cut-off unit 55 will be described later, but not all the power transmission devices 50 are always operated, but only the power transmission device 50 to which the moving body 20 approaches is operated. In the present embodiment, the approach of the moving body 20 is detected by the proximity sensor 62 detecting the magnetic force of the magnet 24 provided on the moving body 20. As the proximity sensor 62, a Hall element, a magnetic sensor, a proximity switch, etc. can be used. When the approach of the moving body 20 is detected by the proximity sensor 62, the control unit 65 changes the resonance condition of the resonance circuit 53, and realizes effective power supply based on resonance between the power receiving coil 31. The detection of the approach / separation of the moving body 20 can also be performed by other methods, such as a structure for detecting the change of mutual inductance caused by the approach of the power receiving coil 31 to the power transmission coil 51, a structure for detecting the tiny magnetic flux emitted by the power receiving coil using the power transmission coil or the detection coil for detection, etc. In addition, the operating power transmission device 50 is not limited to one, and two or more power transmission devices 50 to which the moving body 20 approaches can also be operated.

[0017] If the above content is sorted out from the perspective of contactless power supply, on the ground side, the power supply source is the main power supply 90, which is converted into high-frequency AC power by the main power supply device 70 installed on the ground side, and then supplied to the main power line RFP. Therefore, just by laying the main power line RFP, it is possible to supply power to multiple power transmission devices 50 installed under the road surface RS. Of course, sometimes communication lines are also laid to exchange information with the power transmission device 50, but it is sufficient to use the main power line RFP as the power supply line. In the power transmission device 50, as shown in FIG. Figure 4 As shown, the movable body 20 is supplied with power in a contactless manner via a resonance circuit 53 composed of a resonance capacitor C and a power transmission coil 51 , and the DC power required in the power transmission device 50 is supplied from a DC power supply unit 60 .

[0018] On the other hand, in the power receiving device 30 of the moving body 20, the induced current generated in the power receiving coil 31 magnetically coupled with the power transmitting coil 51 is efficiently received by the power receiving side resonance circuit 33, and supplied to the load device 45 via the rectifier circuit 34. The first power supply unit 41 already described refers to the structure that supplies power to the load device 45 in direct current. On the other hand, the small power used in the moving body 20 is supplied by the second power supply unit 42 already described. In this way, in the present embodiment, the non-contact power supply of all the power supplied to the moving body 20 and used in the moving body 20 includes the power required by the power transmitting device 50, and is realized by the power supplied only from the main power line RFP.

[0019] (A2) Structure and operation of the DC power supply unit and the second power supply unit: The specific configuration and operation of the DC power supply unit 60 in the power transmission device 50 and the second power supply unit 42 in the power reception device 30 will be described. The DC power supply unit 60 and the second power supply unit 42 have the same configuration in the present embodiment. Figure 5 : is a circuit diagram showing the circuit structure of the DC power supply unit 60 and the second power supply unit 42. The circuit inputs a high-frequency, high-voltage AC voltage ACP and outputs a DC low voltage DCP. As the DC power supply unit 60, the input is a high-frequency, high-voltage from the main power line RFP, and for the second power supply unit 42, it is a high-frequency, high-voltage AC induced in the power receiving coil 31. In addition, the following description shows an example of the DC power supply unit 60 or the second power supply unit 42, and other circuit structures can also be easily adopted. For example, a structure that uses a step-down transformer and prepares the necessary voltage as an isolated power supply can also be adopted. In addition, the two power supply units do not need to include the same structure, and different circuit structures can also be adopted.

[0020] Insulating capacitors CC1 and CC2 are respectively installed in series on the two power supply lines LN1 and LN2 of the two power supply units, and a protective diode PD1 is connected in parallel to the output sides of the insulating capacitors CC1 and CC2. A rectifying diode RD1 is connected in series in the forward direction on the output side of the insulating capacitor CC1, and a non-return diode PD2 is connected in series in the reverse direction on the output side of the insulating capacitor CC2. A Zener diode TzD and a smoothing capacitor CF are connected in parallel to the output sides of the two diodes PD1 and PD2. A circuit including at least a rectifying diode RD1 is referred to as a rectifying unit RE, and a circuit including a Zener diode TzD and a smoothing capacitor CF is referred to as a stabilized power supply unit SP. The rectifying unit RE sometimes includes a protective diode PD1 or a non-return diode PD2.

[0021] The DC power supply unit 60 and the second power supply unit 42 having this circuit structure are insulated from the high-frequency, high-voltage AC voltage ACP by the insulating capacitors CC1 and CC2, and an AC voltage is generated between the two power lines LN1 and LN2 according to the change of the AC voltage ACP. Only when the power line LN1 side of the alternating voltage becomes higher than the other power line LN2, the charge accumulated in the insulating capacitors CC1 and CC2 charges the smoothing capacitor CF via the rectifying diode RD1, but the part of the alternating voltage exceeding the Zener breakdown voltage (hereinafter referred to as the Zener voltage) of the Zener diode TzD flows through the Zener diode TzD and is recovered via the non-return diode PD2, so the potential at both ends of the smoothing capacitor CF does not exceed the Zener voltage of the Zener diode TzD. Therefore, the DC low voltage DCP is maintained at the Zener voltage. When the AC voltage ACP is reversed, the power line LN1 side and the power line LN2 side maintain a potential difference of the forward direction voltage reduction amount of the protection diode PD1, so there is no effect on the smoothing capacitor CF. Although the DC power supply unit 60 and the second power supply unit 42A are connected to the high-frequency, high-voltage AC voltage ACP, only the current corresponding to the charge accumulated in the insulating capacitors CC1 and CC2 flows through the power supply lines LN1 and LN2 in one cycle of the AC, so the amount of power output by the circuit can be easily adjusted by using the capacitance of the insulating capacitors CC1 and CC2. If the amount of power handled by the DC power supply unit 60 and the second power supply unit 42 is small, that is, the capacitance can be reduced, it is possible to use capacitors with a higher withstand voltage, such as ceramic capacitors, instead of using more film capacitors and other capacitors with a lower withstand voltage in the power supply circuit, as the insulating capacitors CC1 and CC2, which can be easily achieved even when the AC voltage ACP is high.

[0022] Furthermore, by using the insulating capacitors CC1 and CC2, it is possible to easily separate the side that supplies the AC voltage ACP to the DC power supply unit 60 and the second power supply unit 42, that is, the main power line RFP and the power line of the first power supply unit 41, and it is possible not to be affected by noise and the like. As a result, the possibility of malfunction of the control circuit and the like using the DC power supply unit 60 and the second power supply unit 42 can be reduced. In addition, there is no need for a step-down component such as a transformer that steps down the voltage from a high voltage, and the circuit can be constructed in a small size. Furthermore, since no resistor is used in the circuit structure, the loss caused by the resistor can be eliminated and the efficiency of the circuit can be improved.

[0023] (A3) Structure and operation of the power transmission device: Figure 6The structure of the power transmission device 50 of the first embodiment is shown. As shown in the figure, the power transmission device 50 includes: a first capacitor Cs and a second capacitor Cr that operate under the AC voltage ACP applied to the two power lines NL1 and NL2 and form the resonance circuit 53 described above together with the power transmission coil 51; a first switch SW1 that turns on and off the connection of the second capacitor Cr, and a cut-off unit 55 that cuts off the application of the AC voltage ACP to the resonance circuit 53. When the first switch SW1 is turned on (connected state), the second capacitor Cr is connected in parallel with the first capacitor Cs. The structure using the first switch SW1 is equivalent to a change circuit. In the resonance circuit 53, two capacitors are connected in series with the power transmission coil 51 to form a series resonance (SS) circuit. The frequency of the AC voltage ACP in this embodiment is 85kHz, and the capacitance of the first capacitor Cs and the second capacitor Cr are set so that when the first switch SW1 is turned on, that is, the two capacitors are connected in parallel and the capacitance relative to the inductance of the power transmission coil 51 becomes the sum of the capacitances of the two capacitors, the resonance frequency of the resonance circuit 53 coincides with the frequency of the AC voltage ACP. On the other hand, when the first switch SW1 is in the off state, the resonant frequency of the resonant circuit 53 composed of the power transmission coil 51 and the first capacitor Cs deviates from the frequency of the AC voltage applied by the AC voltage ACP. Since AC is applied to the two power lines NL1 and NL2, it is impossible to call one of the lines the ground line GND, but for convenience, in the following description, the power line NL2 is sometimes called the ground line GND.

[0024] The power transmission device 50 includes a driver 67 for driving the first switch SW1 and a driver 68 for driving the cut-off unit 55. The two drivers are connected to the output ports P1 and P2 of the control unit 65, and drive the first switch SW1 and the cut-off unit 55 when the ports P1 and P2 become high levels. The cut-off unit 55 determines whether the AC voltage ACP is applied to the resonant circuit 53. As long as the cut-off unit 55 is a component that can be electrically connected and disconnected, such as a relay contact, a fuse, or a semiconductor switch element, it can be a component that operates reversibly or a component that operates irreversibly. In the first embodiment, the cut-off unit 55 is a method of reversibly operating using a relay or a semiconductor switch, but it can also be configured using a component that is irreversibly disconnected according to a signal from the outside. For example, it can also be a thermal fuse including a heater, and the heater is heated by a signal from the driver 68 to melt the fuse. Alternatively, it can also be configured so that once disconnected, it will not return to the conductive state unless there is a recovery process from the manual or control unit 65, like a circuit breaker.

[0025] In addition, the power transmission device 50 is also provided with the above-mentioned abnormality detector 61 and proximity sensor 62. The abnormality detector 61 detects abnormalities of the power transmission device 50, and may be, for example, a current sensor that detects overheating, overcurrent, etc. of the power transmission device 50. If it is a current sensor, the abnormality detector 61 is directly provided in the resonant circuit 53. In the case of a sensor that detects overheating of the power transmission coil 51, etc., the abnormality detector 61 is provided to be thermally coupled with the detection object. Alternatively, it may be a device that processes with the control unit 65 or the control circuit 43 on the power receiving device 30 side and detects abnormalities as the contactless power supply system 100. For example, the situation where the proximity sensor 62 mistakenly detects the proximity of the power receiving device 30 may be detected as an abnormality. In this case, the power transmission device 50 may also have a communication unit that communicates with the power receiving device 30.

[0026] The control unit 65 controls the transmission of power from the power transmission device 50 to the power reception device 30 . Figure 7 The flowchart of shows the power transmission control program executed by the control unit 65. The power transmission control program is executed during the period when the AC voltage ACP is applied to the power transmission device 50 and the DC power supply unit 60 supplies the DC power to the control unit 65. When the process starts, first, the process of reading the signal from the abnormality detector 61 is performed (step S100). Based on the signal read from the abnormality detector 61, the occurrence of the abnormality is judged (step S110). In particular, when the occurrence of the abnormality is not confirmed, the control unit 65 reads the signal from the moving body 20 from the proximity sensor 62 (step S120), and judges whether the moving body 20 is close (step S130).

[0027] If the moving body 20 approaches (step S130: Yes), the output port P1 is set to a high level, and the first switch SW1 is turned on (step S140). As a result, the second capacitor Cr is connected in parallel with the first capacitor Cs, and the resonant circuit 53 is in a resonant state. On the other hand, if the moving body 20 does not approach (step S130: No), the port P1 is set to a low level, and the first switch SW1 is turned off (step S145). As a result, the connection between the second capacitor Cr and the first capacitor Cs is released, and the resonant circuit 53 is in a non-resonant state.

[0028] After that, it is determined whether the power transmission is terminated (step S150), and the process returns to step S100 and continues except when the operation of the power transmission device 50 is terminated. The termination of the operation of the power transmission device 50 refers to, for example, the elapse of a predetermined operation time of the power transmission device 50. In addition, it includes the case where power is not supplied from the DC power supply unit 60.

[0029] In the process of repeating the processing from step S100 to step S150, if the judgment in step S110 is "yes", that is, if it is judged that some kind of abnormality has occurred by reading the output from the abnormality detector 61, the port P2 is set to a high level and the cut-off unit 55 is activated to become a non-conductive state (step S200). As a result, the AC voltage ACP is not applied to the resonance circuit 53. Therefore, when some kind of abnormality occurs, such as an abnormality such as overheating of the power transmission coil 51, the cut-off unit 55 is activated, so the AC voltage ACP is not applied to the resonance circuit 53, and a large current caused by resonance does not flow. Therefore, it is possible to suppress the occurrence of problems such as a large power load being applied to the main power supply device 70 due to the occurrence of an abnormality and the main power supply device 70 failing.

[0030] As one of such abnormalities, there is a case where the power transmission device 50 assumes that the power reception coil 31 is close to the power transmission coil 51, and sets the resonance circuit 53 to a resonance state, even though the power reception coil 31 of the moving body 20 is not magnetically coupled with the power transmission coil 51. Such an abnormality may be caused by a failure of the proximity sensor 62 or the like. In this case, in the present embodiment, by using the abnormality detection of the abnormality detector 61 (step S110), the cut-off unit 55 is operated to cut off the power supply to the resonance circuit 53, so that a large current can be suppressed from flowing in the resonance circuit 53. As a result, the occurrence of a failure of the main power supply device 70 can be suppressed. Therefore, the operation of the power transmission device 50 in which the abnormality occurs among the plurality of power transmission devices 50 is stopped, and the other power transmission devices 50 can be kept in use. As a result, it is not necessary to stop the moving body 20 immediately. Therefore, it is possible to suppress the occurrence of a problem that a malfunction occurs in the main power supply device 70 due to a failure of one power transmission device 50, resulting in failure to supply power to the moving body 20.

[0031] In the present embodiment, when an abnormality occurs, the cut-off unit 55 is operated to stop applying voltage to the resonant circuit 53, but the power supply to the DC power supply unit 60 continues. Therefore, since the control unit 65 can also continue to operate, the operation of the cut-off unit 55 via the driver 68 can continue (step S200). In addition, during this period, the content of the abnormality can also be reported to the outside, or the occurrence of an abnormality, for example, can be reported to the display unit included in the power transmission device 50. In addition, even if the cut-off unit 55 uses a normally open relay or semiconductor switch, it is useful to cut off the power supply to the resonant circuit 53 by default when the AC voltage ACP is supplied to the power transmission device 50. In this case, the control unit 65 that receives the power supply from the DC power supply unit 60 can also operate the cut-off unit 55 via the driver 68, close (close) the normally open contact, and start using the resonant circuit 53 for power supply. Thus, when the power supply to the control unit 65 or the driver 68 is interrupted, the cutoff unit 55 returns to the OFF state, and the power supply to the resonance circuit 53 by the power transmission device 50 that has detected the abnormality can be cut off, thereby achieving fail-safe.

[0032] As the abnormality detected by the abnormality detector 61 , various forms can be assumed, such as overheating of the power transmission coil 51 , overcurrent of the current flowing through the resonance circuit 53 , or abnormality on the moving body 20 side being acquired using communication or the like.

[0033] B. Second Implementation Method: Next, a power transmission device 50A according to a second embodiment will be described. Fig. 8A : is a circuit structure diagram of the power transmission device 50A. The power transmission device 50A of the second embodiment includes the same structure as the first embodiment, except that it includes an overcurrent melting type fuse 56 instead of the cut-off section 55 and includes a switching section 58A. The switching section 58A includes the first switch SW1 for switching the resonance state described in the first embodiment and the second switch SW2 for short-circuiting the output side of the fuse 56 and the ground line GND. In addition, when the moving body 20 approaches, the structure of the resonant circuit 53 for supplying power to the power receiving device 30 in a non-contact manner is the same as that of the first embodiment. In the second embodiment, the resonant frequency of the resonant circuit 53A is also achieved by switching the connection between the first capacitor Cs and the second capacitor Cr. As the structure of this change circuit, it is regarded as a part of the switching section 58A in the second embodiment and below.

[0034] Figure 8BThe on / off state of the first switch SW1 and the second switch SW2 and the operating state of the power transmission device 50A are shown. As shown in the figure, the second switch SW2 is disconnected by default. In this state (normal), the fuse 56 does not operate, and the current required by the resonant circuit 53 flows. When the occurrence of an abnormality is detected and the control unit 65 sets the port P2 to a high level, and the second switch SW2 is turned on via the driver 68, since the connection point between the fuse 56 and the power transmission coil 51 is short-circuited to the ground line GND, the current during the short circuit (hereinafter referred to as the melting current) flows through the fuse 56, and the overcurrent melting type fuse 56 melts. As a result, the fuse 56 is irreversibly disconnected, and the AC voltage ACP is not applied to the resonant circuit 53. As in the first embodiment, in normal times, when the first switch SW1 is turned on, the resonant circuit 53 is in a resonant state, and when the first switch SW1 is turned off, the resonant circuit 53 is in a non-resonant state.

[0035] In the power transmission device 50A of the second embodiment described above, when the control unit 65 determines that an abnormality has occurred, the port P2 is set to a high level, and the second switch SW2 is turned on via the driver 68. As a result, a short-circuit current flows through the fuse 56, and the fuse 56 is blown. With this, the short-circuit current stops, and the power supply from the AC voltage ACP to the resonance circuit 53 is also cut off. As a result, similar to the first embodiment, it is possible to prevent an overcurrent from continuing to flow in the resonance circuit 53 due to an abnormality occurring in the power transmission device 50A, and it is possible to suppress the occurrence of a malfunction in the main power supply device 70 due to an overload exceeding the allowable range of the main power supply device 70 due to an overcurrent or the like. In addition, in the second embodiment, since the melting current of the melting fuse 56 does not flow through the power transmission coil 51, there is no concern that a leakage magnetic flux will be generated when the fuse 56 is melted.

[0036] like Figure 8CAs shown, the circuit structure of the second embodiment can also be provided with a current limiter 59 having a specified impedance Z in the path of the fusing current flowing when the second switch SW2 is turned on. In the circuit shown in the figure, when the control unit 65 detects an abnormality and turns on the second switch SW2, the fusing current flows through the current limiter 59, and the fuse 56 is blown. Therefore, the same effect as the second embodiment is achieved. Moreover, since the magnitude of the fusing current can be limited to a current value that can blow the fuse 56 by the current limiter 59, it can be smaller than the short-circuit current, and it is also easy to design so that an excessive load is not applied to the main power supply device 70 when the fuse 56 is blown. As the current limiter 59, it can be a single element such as a resistor R or a capacitor C. If the fuse 56 is blown, a current exceeding this will not flow, so it can also be a single coil L. Of course, they can also be combined to adjust the time variation of the fusing current to a desired curve. In addition, if a resistor or a coil is used, or various elements are combined to limit the inrush current value of the fuse current and limit its maximum value, not only can the burden on the main power supply device 70 be reduced, but the possibility of welding of the second switch SW2 can also be suppressed.

[0037] C. Third Implementation Method: use Fig. 9 The power transmission device 50B of the third embodiment is described. The power transmission device 50B of the third embodiment has a structure substantially the same as the power transmission device 50A of the second embodiment, except for the connection relationship of the switching unit. In the power transmission device 50B, the structure of the second switch SW2 of the switching unit 58B is different from that of the second embodiment in that the output side of the fuse 56 is not directly connected to the ground line GND, but is connected via the second capacitor Cr. In addition, the relationship between the on / off of the first switch SW1 and the second switch SW2 and the operating state of the power transmission device 50B is the same as that of the second embodiment. Figure 8B The relationship shown in is the same.

[0038] In the third embodiment, the magnitude of the blowing current flowing through the fuse 56 when the second switch SW2 is turned on is determined by the impedance of the second capacitor Cr at the frequency of the AC voltage ACP. Figure 8B As shown, in normal state, since the power supply current supplied to the moving body 20 using the resonance of the resonance circuit 53 flows through the fuse 56 when the first switch SW1 is turned on, the current becomes Fusing current > Rated current during power supply (Formula 1) The capacity of the second capacitor Cr is set in a manner. Since the impedance of the second capacitor Cr that determines the fusing current depends not only on the capacitance of the second capacitor Cr but also on the frequency of the AC voltage ACP, the above-mentioned (Formula 1) can be satisfied. In addition, in order to optimize the relationship between the capacitance (Cs+Cr) for making the resonant circuit 53 a resonant state by switching the first switch SW1 and the capacitance (Cs) for making the resonant circuit 53 a non-resonant state and the above-mentioned (Formula 1), it is sufficient to form the second capacitor Cr with a plurality of capacitors connected in series and to make the fusing current when the second switch SW2 is turned on only flow through a part of the capacitors. In the case where a plurality of capacitors are connected in parallel, it is sufficient to form the second switch SW2 with a c-type contact. When the a-contact is turned on, all the capacitors are connected in parallel and the resonant circuit 53B is set to a resonant state. When the a-contact is switched to the b-contact, the fusing current flows only through a part of the capacitors of the plurality of capacitors.

[0039] According to the power transmission device 50B of the third embodiment having such a configuration, not only can substantially the same effects as those of the second embodiment be achieved, but also the fusing current can be made smaller than the short-circuit current, thereby reducing the load applied to the main power supply device 70. In addition, the current value flowing to blow the fuse 56 can be set to a predetermined value.

[0040] D. Fourth Implementation Method: use Fig.10 The power transmission device 50C of the fourth embodiment is described below. The connection relationship of the switching unit of the power transmission device 50C of the fourth embodiment is different from that of the power transmission device 50 of the second embodiment and the third embodiment. In the power transmission device 50C, the second switch SW2 of the switching unit 58C is not connected to the output side of the fuse 56, but is provided at a position where the connection point between the power transmission coil 51 of the resonance circuit 53C and the first capacitor Cs and the ground line GND are connected / disconnected. In addition, the relationship between the on / off of the first switch SW1 and the second switch SW2 and the operating state of the power transmission device 50C is the same as that in the second embodiment. Figure 8B The relationship shown in is the same.

[0041] In the fourth embodiment, when an abnormality is detected and the control unit 65 sets the port P2 to a high level and turns on the second switch SW2 via the driver 68, a fusing current flows through the power transmission coil 51. The magnitude of the fusing current flowing through the fuse 56 when the second switch SW2 is turned on is determined by the impedance of the power transmission coil 51 at the frequency of the AC voltage ACP. Figure 8B As shown, in normal state, since the power supply current supplied to the moving body 20 using the resonance of the resonance circuit 53 flows through the fuse 56 when the first switch SW1 is turned on, the current becomes Fusing current > Rated current during power supply (Formula 1) As described in the third embodiment, in order to simultaneously realize the switching between the resonant state and the non-resonant state of the resonant circuit 53C and make the impedance of the power transmission coil 51 that determines the fusing current appropriate, it is sufficient to provide a connector with a different number of windings in the power transmission coil 51, connect the second switch SW2 to the connector, and allow the fusing current to flow through a portion of the power transmission coil 51 when the second switch SW2 is turned on.

[0042] According to the power transmission device 50C of the fourth embodiment having such a configuration, substantially the same operational effects as those of the third embodiment are achieved.

[0043] E. Fifth Implementation Method: use Fig.11A The power transmission device 50D of the fifth embodiment is described below. The power transmission device 50D of the fifth embodiment is different from the power transmission device 50 of the above-described embodiment in that a relay circuit 80D is used, a driver 69 is used instead of the drivers 67 and 68, and a current sensor 85 provided in the relay circuit 80D is used instead of the proximity sensor 62. The relay circuit 80D of the power transmission device 50D includes a relay coil 81 tightly coupled with the power transmission coil 51, a third capacitor Ch forming a resonance circuit together with the relay coil 81, a second switch SW2 that short-circuits both ends of the relay coil 81, and a current sensor 85 that detects a resonance current. The relay circuit 80D is provided to detect the approach of the moving body 20 having the power receiving coil 31. The approach of the power receiving coil 31 is detected by the increase or decrease of the resonance current detected by the current sensor 85. Although the connection from the current sensor 85 to the control unit 65 is not shown for the sake of convenience, the control unit 65 reads the output of the current sensor 85 and detects the approach of the moving body 20. That is, the current sensor 85 functions as a proximity sensor. Fig.11A In the figure, two parallel straight lines are used to indicate that the coils are in a state of mutual magnetic coupling.

[0044] In this embodiment, the second switch SW2 is provided in the relay circuit 80D. Therefore, the switching unit 58D is a circuit including the first switch SW1 connected to the second capacitor Cr for resonance of the resonance circuit 53D and the second switch SW2 provided in the relay circuit 80D. The states of the first switch SW1 and the second switch SW2 constituting the switching unit 58D are switched by the output of the driver 69 according to the states of the ports P1 and P2 of the control unit 65.

[0045] As shown in the figure, the driver 69 of the present embodiment is composed of two OR gates OR1, OR2 and an inverter INV connected to one input terminal of the OR gate OR2. Ports P1 and P2 of the control unit 65 are respectively connected to the two input terminals of the OR gate OR1. Port P1 of the control unit 65 is connected to one of the input terminals of the OR gate OR2 via the inverter INV, and port P2 is connected to the other input terminal via the inverter INV. As a result, if port P2 is not a high level (H), regardless of the state of port P1, both outputs of the driver 69 become a high level, and the first switch SW1 and the second switch SW2 become an on state. On the other hand, if port P2 is a low level (L), the two outputs of the driver 69 exclusively become a high level or a low level according to the state (high / low) of port P1.

[0046] The switching unit 58D of the power transmission device 50D is composed of a first switch SW1 and a second switch SW2, similarly to the previous embodiment. The first switch SW1 and the second switch SW2 of the switching unit 58D are switched by the control unit 65. Fig. 11B , the states of ports P1 and P2 of the control unit 65, the on / off of the first switch SW1 and the second switch SW2, and the state of the power transmission device 50D are shown. As shown in the figure, in normal state, port P2 of the control unit 65 is kept at a low level. At this time, if port P1 is at a low level, the first switch SW1 is turned off, the second switch SW2 is turned on, and the resonant circuit 53D remains in a standby state. If port P1 is at a high level, the first switch SW1 is turned on, the second switch SW2 is turned off, and the resonant circuit 53D enters a resonant state. Since the inverter INV is provided, the outputs of the two OR gates OR1 and OR2 are exclusively turned on / off.

[0047] When an abnormality is detected, the control unit 65 makes the port P2 a high level. As a result, both outputs of the driver 69 become a high level, and as a result, both the first switch SW1 and the second switch SW2 are turned on. In this state, a large current flows through the resonant circuit 53D, melting the fuse 56. When the second switch SW2 is turned on, the fuse 56 is melted, so even if a short circuit failure occurs in the second switch SW2, it is possible to cope with the abnormality. At this time, since the melting current flows through the power transmission coil 51, a large magnetic flux is generated in the period before the fuse 56 is melted, but since an induced current is generated in the relay coil 81 to offset the magnetic flux generated by the power transmission coil 51, the leakage magnetic flux can be eliminated.

[0048] According to the power transmission device 50D of the fifth embodiment described above, by using the relay circuit 80D, it is possible to reliably detect the approach of the moving object 20 through the relationship with the power receiving coil 31. In addition, in order to detect the moving object 20, the magnet 24 and the like are not required, and erroneous detection due to other magnetic bodies and the like does not occur. The remaining effects are the same as those of the first to fourth embodiments.

[0049] F. Sixth embodiment: Next, use Fig.12 The sixth embodiment of the power transmission device 50E is described below. In the sixth embodiment of the power transmission device 50E, as shown in the figure, a relay circuit 80E is used as in the fifth embodiment, but the relay circuit 80E and the resonant circuit 53E are not electrically separated, but form a closed circuit. From the appearance, the resonant circuit 53E and the relay circuit 80E become loads connected in series with respect to the AC voltage ACP. The structure of the switching unit 58E and the relay circuit 80E in the power transmission device 50E, the internal structure of the driver 69, the connection between the output of the driver 69 and the first switch SW1 and the second switch SW2, the use of the current sensor 85 instead of the proximity sensor 62, etc. are the same as those in the fifth embodiment. In addition, the operation of the sixth embodiment is the same as that of the fifth embodiment. Fig. 11B The fifth embodiment shown is the same.

[0050] According to the power transmission device 50E of the sixth embodiment described above, not only the same operational effects as those of the fifth embodiment are achieved, but also the relay circuit 80E and the resonance circuit 53E are directly connected, so that the structure can be simplified.

[0051] G. Seventh embodiment and its variations: In the fifth and sixth embodiments described above, relay circuits 80D and 80E are used, and by turning on (on state) the second switch SW2 provided in the relay circuits 80D and 80E together with the first switch SW1 provided in the resonant circuits 53D and 53E, a blowing current flows to blow the fuse 56, but the fuse 56 may also be blown regardless of the operation of the relay circuit 80D. Fig.13 Such a circuit configuration is shown as a power transmission device 50F according to the seventh embodiment. In this example, a resonance circuit 53F and a switch unit 58F have the same configuration as the resonance circuit 53B and the switch unit 58B according to the third embodiment.

[0052] On the other hand, in the present embodiment, as a resonant capacitor of the relay circuit 80F, the relay circuit 80F has a fourth capacitor Cg in addition to the third capacitor Ch. In synchronization with the switching of the resonant circuit 53F to the resonant state and the non-resonant state, the relay circuit 80F is also switched to the resonant state and the non-resonant state. For this purpose, a main first switch SW11 is provided in the resonant circuit 53F, and a sub-first switch SW12 is provided in the relay circuit 80F. The two main first switches SW11 and the sub-first switch SW12 activate their ports P1 through the control unit 65, and are switched to be turned on (conducting state) via the driver 67. At this time, the capacitance of the resonant capacitor of the resonant circuit 53F is the capacitance obtained by adding the capacitances of the first capacitor Cs and the second capacitor Cr, and similarly, the capacitance of the resonant capacitor of the relay circuit 80F is the capacitance obtained by adding the capacitances of the third capacitor Ch and the fourth capacitor Cg. When the two switches SW11 and SW12 are in the on state, the resonant circuit 53F and the relay circuit 80F are respectively in the resonant state. In addition, when the main first switch SW11 and the auxiliary first switch SW12 are turned off (non-conductive state), the resonant circuit 53F and the relay circuit 80F are respectively in a non-resonant state. The opening / closing of the main first switch SW11 and the auxiliary first switch SW12 is performed based on the detection state of the approach of the moving body 20 using the current sensor 85. When the moving body 20 approaches, it becomes a resonant state, and power is supplied from the power transmission device 50F to the moving body 20 side.

[0053] When the abnormality detector 61 determines that some abnormality has occurred in the power supply from the power transmission device 50F to the moving body 20, the second switch SW2 is turned on to generate a fusing current and blow the fuse 56, as in the third embodiment. The relationship between the on / off of the first switch SW1 (here, SW11 and SW12) and the second switch SW2 and the operating state of the power transmission device 50F is as follows: Figure 8B Same as shown.

[0054] Thus, even if the relay circuit 80F is used, regardless of the operation of the relay circuit 80F, when an abnormality occurs, the fuse 56 can be blown to prevent an overcurrent from flowing through the resonance circuit 53F, thereby suppressing the possibility of a malfunction in the power transmission device 50F or the main power supply device 70. In addition, the circuit configuration when the relay circuit is used may be various other configurations. For example, Fig.14The structure of the power transmission device 50G shown as a modified example is also possible. The structure shown in the figure includes a relay circuit 80G in the same way as the relay circuit 80F of the seventh embodiment already described, and the power transmission device 50G includes the same circuit structure as the fourth embodiment described above. In this power transmission device 50G, the second switch SW2 of the switching unit 58G is not connected to the output side of the fuse 56, but is set at a position where the connection point between the power transmission coil 51 of the resonant circuit 53G and the first capacitor Cs and the ground line GND are set to be connected / disconnected. In addition, the relationship between the on / off of the first switch SW1 (here, SW11 and SW12) and the second switch SW2 and the operating state of the power transmission device 50F is the same as Figure 8B Such a circuit structure also has the same effect as the fourth embodiment.

[0055] H. Eighth embodiment and its variations: Next, a power transmission device 50H according to an eighth embodiment will be described. Fig.15 : is a circuit configuration diagram of a power transmission device 50H. In the first to seventh embodiments described above, the resonant circuit 53 and the like are configured as a series resonant (SS) circuit, but in the eighth embodiment, the resonant circuit is also configured as a parallel resonant circuit. The power transmission device 50H of the eighth embodiment is different from the circuit configuration of the second embodiment in that the resonant circuit 53H is configured as a parallel resonant (P) circuit composed of a power transmission coil 51 and a parallel resonant capacitor Cp connected in parallel thereto. In addition, in the power transmission device 50H of the eighth embodiment, the first switch SW1 constituting the switching unit 58H is provided on the output side of the fuse 56 of the power line NL1, and the second switch SW2 is provided at the output side of the first switch SW1 in parallel with the resonant circuit 53H connected to the power lines NL1 and NL2.

[0056] In the power transmission device 50H of the eighth embodiment, the control unit 65 turns on / off the first switch SW1 via the driver 68 , and turns on / off the second switch SW2 via the driver 69 . Fig.16The on / off state of the first switch SW1 and the second switch SW2 by the control unit 65 and the operating state of the power transmission device 50H are shown. As shown in the figure, when no abnormality is detected by the abnormality detector 61, that is, in normal state, the first switch SW1 and the second switch SW2 are exclusively turned on and off. If the proximity sensor 62 determines that the moving body 20 is not approaching, the first switch SW1 is maintained to be off and the second switch SW2 is maintained to be on. In this state, since the AC voltage ACP is not applied to the resonance circuit 53H and the two ends of the power transmission coil 51 are short-circuited, power is not transmitted to the power receiving device 30 via the resonance circuit 53H. On the other hand, if the proximity sensor 62 determines that the moving body 20 is in an approaching state, the first switch SW1 is switched on and the second switch SW2 is switched off. In this state, since the AC voltage ACP is applied to the resonance circuit 53H and the two ends of the power transmission coil 51 are not short-circuited, power is transmitted to the power receiving device 30 via the resonance circuit 53H. In this state, regardless of whether the proximity sensor 62 detects the approach of the moving object 20 or not, one of the first switch SW1 and the second switch SW2 is open, so the power line NL1 on the output side of the fuse 56 is not short-circuited to the ground line GND.

[0057] When the abnormality detector 61 detects a certain abnormality, the control unit 65 makes both ports P1 and P2 high level, and turns on both the first switch SW1 and the second switch SW2. As a result, since the connection point between the fuse 56 and the power transmission coil 51 is short-circuited to the ground line GND, the melting current flows through the fuse 56, and the overcurrent melting type fuse 56 melts. Since the melting current does not flow through the power transmission coil 51, no leakage flux is generated when it is melted. In the power transmission device 50H of the eighth embodiment, by setting the resonance circuit 53H as a parallel resonance circuit, the characteristics of the parallel resonance circuit can be utilized, and when the moving body 20 is not approaching, the first switch SW1 is set to be off, so there is no need to change the resonance frequency of the resonance circuit 53H. That is, on the basis of achieving the same effect as the second embodiment, it is not necessary to set the second capacitor Cr, and the circuit structure can be simplified.

[0058] The resonant circuit can adopt various structures. For example, Fig.17 As shown, it can be a series-parallel resonance (SP) circuit structure including a parallel resonance capacitor Cp and a series resonance capacitor Cq connected in series with the power transmission coil 51, a parallel-series resonance (PS) circuit structure in which the series resonance capacitor Cq is arranged on the power supply side, and a series-parallel-series (SPS) resonance circuit structure in which the series resonance capacitor is arranged on both sides. In either case, the operation of the switching unit 58h is the same as Fig.16The actions shown are the same.

[0059] In the eighth embodiment ( Fig.15 ) and its variants ( Fig.17 ), the fuse 56 is blown by turning on the first switch SW1 and the second switch SW2 at the same time, so the blown current becomes a short-circuit current. Figure 8C ), the fusing current can also be set to a current value smaller than the short-circuit current by providing a current limiter 59 having a specified impedance Z in the flow path of the short-circuit current to blow the fuse 56.

[0060] I. Other embodiments: (1) The present disclosure can be implemented in a manner other than the above. The first manner is a manner as a contactless power transmission device. The contactless power transmission device is a power transmission device that operates by receiving power supply from a main power supply device and transmits power to a power receiving device provided at a power supply target in a contactless manner, the power transmission device comprising: a resonant circuit having a power transmission coil that is magnetically coupled to a power receiving coil provided at the power receiving device; an abnormality detection unit that detects an abnormality related to power supply to the power receiving device; a disconnection unit that is provided in a power line that supplies AC power from the main power supply device to the resonant circuit and is capable of switching the power line to a non-conductive state; and a control unit that, when the abnormality is detected by the abnormality detection unit, operates the disconnection unit to stop the power supply from the main power supply device to the resonant circuit. In this way, when an abnormality occurs, the disconnection unit operates, so that the AC power supplied to the resonant circuit is disconnected, and a large current caused by resonance can be prevented from flowing. Therefore, it is possible to suppress the occurrence of a problem in which a large power load is applied to the main power supply device due to the occurrence of an abnormality, and the main power supply device fails.

[0061] As the abnormality that causes the cut-off unit to operate, various situations can be assumed, such as overheating of the power transmission device, overcurrent of the resonance circuit, abnormality notification from the receiving device side, etc. Overheating of the power transmission device can be determined not only when the power transmission coil reaches a preset temperature or the temperature rise per hour exceeds a set value, but also when the capacitor for resonance reaches a set temperature or the ambient temperature in the power transmission device reaches a preset threshold or more.

[0062] In the case where an overcurrent in a resonant circuit is detected as an abnormality, a current sensor may be provided at a location where the current flows during resonance. Of course, the current sensor does not necessarily need to be provided in the circuit. The current flowing through the resonant circuit is alternating current, so an indirect current sensor utilizing electromagnetic induction may also be used. In this way, the possibility of the current sensor itself failing due to overcurrent can be suppressed. In the case of using a relay circuit including a coil tightly coupled to a power transmission coil, overcurrent may also be detected by a current sensor provided in the relay circuit. In addition, abnormality detection may also determine that an abnormality has occurred in the case where a circuit is switched to make the resonant circuit resonant despite the fact that a moving body is not approaching, and other situations where logic is disconnected or blocked. In addition, a structure may be used in which an abnormality is determined to have occurred when a notification that an abnormality has been detected as a system is received from a diagnostic system computer provided in the contactless power supply system.

[0063] (2) In such a structure, the above-mentioned cut-off section may also include at least one of a fuse, a relay contact, and a semiconductor switch element, and the above-mentioned power line is made non-conductive by melting the above-mentioned fuse, opening the above-mentioned relay contact, and disconnecting the above-mentioned semiconductor switch element. In this way, the cut-off section can be easily constructed using existing circuit components. As long as such a cut-off section is a component that can be electrically connected / disconnected, such as a fuse, a relay, a semiconductor switch element, etc., which cuts off the supply of high-frequency power, it can be a component that can be reversibly operated or an irreversibly operated component. In addition, even if it is a component that can be irreversibly operated, such as a fuse, it is not limited to a component that uses the current flowing through the circuit to operate, such as an overcurrent melting type, and a component that can be irreversibly disconnected by a signal from the outside can also be used. For example, it can also be a thermal melting type fuse including a heater, which heats the heater by a signal from a driver to melt the fuse. Alternatively, it can also be constructed like a circuit breaker, which once disconnected, will not return to the conductive state unless it is manually or restored by the control unit. When a disconnection unit that performs reversible action like a relay or a semiconductor switch is used, it is also suitable to implement fault protection by using a normally open relay or a semiconductor switch. In addition, as a disconnection unit that operates irreversibly, when an overcurrent fusing type fuse is used, there is an advantage that the circuit structure can be simplified.

[0064] (3) In the above structures (1), (2), etc., a switching unit may be included. The switching unit switches the resonant circuit to any one of a resonant state in which the resonant circuit transmits power to the power receiving device, a non-resonant state in which the resonant circuit does not transmit power to the power receiving device, and a cut-off operation state in which a predetermined cut-off current flows to operate the cut-off unit. When the control unit detects the abnormality, the switching unit drives the switching unit to switch to the cut-off operation state. In this way, the switching unit can switch between the resonant state, the non-resonant state, and the cut-off operation state. Generally speaking, in a resonant circuit, an abnormal state such as an excessive current flowing is likely to occur when the resonant circuit is in a resonant state. Therefore, switching between such a resonant state / non-resonant state and the cut-off operation state by a single switching unit helps to simplify the structure and stabilize the operation. The switching unit can be easily realized by combining the states of a plurality of switch elements or contacts such as relays. Of course, the switching can be realized by a discrete circuit structure or by using a computer logic operation. In order to realize the cut-off operation state, when an overcurrent-melting type fuse is used in the cut-off portion, the cut-off current is the melting current of the fuse. When a relay contact or a semiconductor switching element is used in the cut-off portion, the cut-off current is used to operate the relay body, or the semiconductor switching element such as FET is operated by the voltage generated by the cut-off current. In the latter case, if a trigger circuit is constructed, and the cut-off current flows to make the trigger circuit a set state or a reset state, even if the cut-off current is lost, the set state or the reset state of the trigger circuit can be maintained afterwards, and the cut-off operation state can be maintained even if the cut-off current flows only for a short time.

[0065] (4) In any of the structures in (1) to (3) above, the resonant circuit includes: a capacitor, which determines the resonant state together with the power transmission coil; and a change circuit, which changes at least one of the inductance of the power transmission coil and the capacitance of the capacitor, and the switching unit switches the resonant state and the non-resonant state by changing at least one of the inductance of the power transmission coil and the capacitance of the capacitor using the change circuit. In this way, the resonant circuit can be easily switched to any of the resonant state and the non-resonant state. The capacitance of the capacitor can be easily switched by arranging a plurality of capacitors in parallel or in series and connecting / disconnecting the connection between them. In addition, a variable capacitance capacitor can also be electronically configured. The inductance of the power transmission coil can be changed by similarly providing a plurality of power transmission coils and switching their connection, or by providing a plurality of connectors in the power transmission coil and switching the connectors. In the case where the power transmission coil includes a magnetic body such as a ferrite core, the inductance can be changed by changing the length of the ferrite core inserted into the power transmission coil.

[0066] (5) In the configuration of (3) or (4), the switching unit may include a capacitor in the circuit through which the cutoff current flows. In this way, the magnitude of the cutoff current can be limited by the impedance of the capacitor for high-frequency power used for resonance.

[0067] (6) In this case, the capacitor may be a capacitor that determines the resonant state of the resonant circuit. In this way, the capacitor can be used as both a capacitor for resonance and a capacitor for limiting the cutoff current, which contributes to the simplification of the structure.

[0068] (7) In the configuration of (3) or (4), the switching unit may include a coil in a circuit through which the cutting current flows. In this way, the magnitude of the cutting current can be limited by the inductance of the coil.

[0069] (8) In this case, the coil may be a part of the power transmission coil. In this way, the coil can be used as both the power transmission coil for resonance and the coil for limiting the cutoff current, which helps simplify the structure.

[0070] (9) The above structure may further include a relay circuit, wherein the relay circuit includes a relay coil magnetically coupled to the power transmission coil, and the resonance state changes as the power reception coil approaches. In this way, even with the structure using the relay circuit, the switching operation of the switching unit can be realized.

[0071] (10) In this case, the relay circuit is electrically separated from the resonant circuit, and the switching unit switches to the cut-off action state by setting the resonant circuit to a resonant state and setting the relay circuit to a non-resonant state, and the cut-off unit is actuated by causing the cut-off current to flow through the resonant circuit.

[0072] (11) Alternatively, the relay circuit may be connected in series with the resonant circuit, and the switching unit switches to the cut-off operation state by setting the resonant circuit to a resonant state and short-circuiting the relay coil to set the relay circuit to a non-resonant state, and the cut-off unit is operated by causing the cut-off current to flow through the resonant circuit and the short-circuited relay circuit. According to these structures, the cut-off unit can be operated by the cut-off current with a simple structure.

[0073] (12) In addition to the above-mentioned embodiment, a method as a non-contact power transmission method can also be implemented. The non-contact power transmission method is a power transmission method for transmitting power to a power receiving device provided at a power supply target in a non-contact manner, wherein the non-contact power transmission method supplies AC power from a main power supply device to a resonant circuit having a power transmission coil that is magnetically coupled with a power receiving coil provided at the power receiving device via a power line, sets the resonant circuit to a resonant state when the power receiving coil is close to the power transmission coil, and sets the resonant circuit to a non-resonant state when the power receiving coil is not close to the power transmission coil, and when an abnormality related to power supply to the power receiving device is detected, the power line is switched to a non-conductive state, and the supply of the AC power from the main power supply device to the resonant circuit is cut off. In this way, when an abnormality occurs, since the power line is switched to a non-conductive state, the AC power supplied to the resonant circuit is cut off, and a large current caused by resonance can be prevented from flowing. Therefore, it is possible to suppress the occurrence of a problem such as a large power load being applied to the main power supply device due to the occurrence of an abnormality, and the main power supply device failing.

[0074] (13) In addition to the above-mentioned embodiment, a contactless power supply system may be implemented. The contactless power supply system is a power supply system including a main power supply device, a power transmission device, and a power receiving device, wherein the power transmission device receives power from the main power supply device and operates, and the power receiving device receives power from the power transmission device in a contactless manner, and the power receiving device includes: a power receiving side resonance circuit, wherein the power receiving side resonance circuit includes a power receiving coil; a rectifier circuit, wherein the rectifier circuit rectifies the alternating current induced in the power receiving side resonance circuit and extracts direct current power; and a load device, wherein the load device operates using the direct current power, and the power transmission device The device includes: a power transmission side resonance circuit, the power transmission side resonance circuit having a power transmission coil coupled to the power receiving coil magnetic field; a cut-off unit, the cut-off unit being provided in a power line for supplying power from the main power supply device to the power transmission side resonance circuit, and capable of switching the power line to a non-conductive state; an abnormality detection unit, the abnormality detection unit detecting an abnormality related to power supply to the power receiving device; and a control unit, the control unit operating the cut-off unit to cut off the power supply to the power transmission side resonance circuit when the abnormality is detected by the abnormality detection unit. The power supply system can supply power from the power transmission device to the power receiving device in a non-contact manner, and when an abnormality related to power supply to the power receiving device occurs, the cut-off unit is operated to cut off the power supply to the power transmission side resonance circuit, so that a large current caused by resonance can be prevented from flowing in the power transmission device. Therefore, it is possible to suppress the occurrence of problems such as a large power load being applied to the main power supply device due to the occurrence of an abnormality and a failure of the main power supply device.

[0075] (14) The control unit and method described in the present disclosure may also be implemented by a dedicated computer, which is provided by constituting a processor and a memory, and the processor is programmed to execute one or more functions embodied by a computer program. Alternatively, the control unit and method described in the present disclosure may be implemented by a dedicated computer, which is provided by constituting a processor composed of one or more dedicated hardware logic circuits. Alternatively, the control unit and method described in the present disclosure may be implemented by one or more dedicated computers, which are constituted by a combination of a processor and a memory programmed to execute one or more functions and a processor constituted by one or more hardware logic circuits. In addition, the computer program may also be stored in a computer-readable non-temporary tangible recording medium as an instruction executed by a computer. "Computer-readable non-temporary tangible recording medium" is not limited to portable recording media such as floppy disks or CD-ROMs, but also includes various internal storage devices in the computer such as RAM or ROM, and external storage devices fixed to the computer such as hard disks. That is, "computer-readable non-temporary tangible recording medium" has a broad meaning including any recording medium that can fix data packets rather than being temporary.

[0076] The present disclosure is not limited to the above-mentioned embodiments, and can be implemented by various structures within the scope of the above-mentioned subject matter. For example, the technical features in the embodiments corresponding to the technical features in each method described in the invention content section can be appropriately replaced or combined to solve part or all of the above-mentioned technical problems, or to achieve part or all of the above-mentioned effects. In addition, the above-mentioned technical features can be appropriately deleted as long as they are not described as necessary structures in this specification.

Claims

1. A contactless power transmission device, the contactless power transmission device being a power transmission device (50) that receives power supply from a main power supply device (70) and transmits power to a power receiving device (30) provided at a power supply target in a contactless manner, the contactless power transmission device comprising: a resonance circuit (53) having a power transmission coil (51) magnetically coupled to a power receiving coil (31) provided in the power receiving device; an abnormality detection unit (61) for detecting an abnormality related to power supply to the power receiving device; a cut-off unit (55, 56) provided on a power line (NL1, NL2) for supplying AC power from the main power supply device to the resonant circuit and capable of switching the power line to a non-conductive state; as well as A control unit (65) operates the cutoff unit to stop the supply of power from the main power supply device to the resonance circuit when the abnormality is detected by the abnormality detection unit.

2. The contactless power transmission device according to claim 1, wherein: The disconnection unit includes at least one of a fuse (56), a relay contact, and a semiconductor switch element, and the power line is put into a non-conductive state by melting of the fuse, opening of the relay contact, and disconnection of the semiconductor switch element.

3. The contactless power transmission device according to claim 1, wherein: The device comprises a switching unit (58A, 58B, 58C, 58D, 58E, 58F, 58G) for switching between a resonant state in which the resonant circuit transmits power to the power receiving device, a non-resonant state in which the resonant circuit does not transmit power to the power receiving device, and a cut-off operation state in which a cut-off current of a predetermined size flows to operate the cut-off unit. When the abnormality is detected, the control unit drives the switching unit to switch to the shutoff operation state.

4. The contactless power transmission device according to claim 3, wherein: The resonant circuit includes: a capacitor (Cs, Cr) that determines a resonant state together with the power transmission coil; and a changing circuit (SW1, SW11) that changes at least one of the inductance of the power transmission coil and the capacitance of the capacitor. The switching unit switches between the resonant state and the non-resonant state by changing at least one of the inductance of the power transmission coil and the capacitance of the capacitor using the changing circuit.

5. The contactless power transmission device according to claim 3, wherein: The switching unit includes a capacitor in a circuit through which the cutting current flows.

6. The contactless power transmission device according to claim 5, characterized in that: The capacitor is a capacitor that determines the resonance state of the resonance circuit.

7. The contactless power transmission device according to claim 3, wherein: The switching unit includes a coil (51) in a circuit through which the cutting current flows.

8. The contactless power transmission device according to claim 7, wherein: The coil is a part of the power transmission coil.

9. The contactless power transmission device according to any one of claims 3 to 8, characterized in that: The invention also includes a relay circuit (80D, 80E, 80F, 80G), the relay circuit including a relay coil (81) magnetically coupled to the power transmission coil, and the resonance state of which changes due to the proximity of the power reception coil.

10. The contactless power transmission device according to claim 9, wherein: The relay circuit is electrically separated from the resonant circuit. The switching unit switches to the cutoff operation state by setting the resonance circuit to a resonance state and the relay circuit to a non-resonance state, and operates the cutoff unit by causing the cutoff current to flow through the resonance circuit.

11. The contactless power transmission device according to claim 9, wherein: The relay circuit is connected in series with the resonant circuit, The switching unit switches to the cutoff operation state by setting the resonant circuit to a resonant state, short-circuiting the relay coil, and setting the relay circuit to a non-resonant state, and operates the cutoff unit by causing the cutoff current to flow through the resonant circuit and the short-circuited relay circuit.

12. The contactless power transmission device according to claim 1, wherein: The resonant circuit includes a resonant capacitor used together with the power transmission coil, and the power transmission coil and the resonant capacitor constitute at least one of a series resonant circuit, a parallel resonant circuit, a series-parallel resonant circuit, a parallel-series resonant circuit, and a series-parallel-series resonant circuit.

13. A non-contact power transmission method, the non-contact power transmission method being a power transmission method for transmitting power to a power receiving device provided at a power supply target in a non-contact manner, The contactless power transmission method supplies AC power from a main power supply device via a power line to a resonant circuit having a power transmission coil that is magnetically coupled to a power receiving coil provided in the power receiving device. the resonant circuit is set to a resonant state when the power receiving coil is close to the power transmitting coil, and is set to a non-resonant state when the power receiving coil is not close to the power transmitting coil, When an abnormality related to power supply to the power receiving device is detected, the power line is switched to a non-conductive state, and supply of the AC power from the main power supply device to the resonance circuit is cut off.

14. A contactless power supply system, the contactless power supply system (100) comprising a main power supply device, a power transmission device and a power receiving device, the power transmission device receiving power from the main power supply device and operating, the power receiving device receiving power from the power transmission device in a contactless manner, The power receiving device comprises: A power receiving side resonance circuit (33), the power receiving side resonance circuit comprising a power receiving coil; a rectifier circuit (34) for rectifying the alternating current induced in the power receiving side resonance circuit to extract direct current power; as well as a load device (45) which operates using the DC power, The power transmission device comprises: a power transmission side resonance circuit, the power transmission side resonance circuit having a power transmission coil magnetically coupled to the power receiving coil; a cutoff unit provided on a power line from the main power supply device to the power transmission-side resonance circuit and capable of switching the power line to a non-conductive state; an abnormality detection unit that detects an abnormality related to power supply to the power receiving device; and a control unit that, when the abnormality detection unit detects the abnormality, operates the cutoff unit to cut off the power supply to the power transmission-side resonant circuit.

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