Power receiving device, non-contact power supply system, and non-contact power supply method

Abstract

A first power supply unit (41) rectifies AC power received by a power receiving coil (31) that receives power in a non-contact manner from the outside using magnetic field coupling, converts the rectified AC power into DC power, and supplies the DC power as main power to be used in a load device (45). A second power supply unit (42) is connected to a preceding stage of the first power supply unit, and outputs power for controlling the first power supply unit in a direct current manner. As a result, in a circuit configuration when the load device receives power, it is possible to stably secure a power supply for control.

Description

Citation of related applications

[0001] This application is based on patent application No. 2022-099061 filed in Japan on June 20, 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 receiving and supplying power in a contactless manner. Background Art

[0003] In the past, various contactless power supply technologies have been proposed for supplying power to a moving body in a contactless manner from a driving surface. For example, Japanese Patent Publication No. 2014-138496 shows a contactless power supply structure that receives power supply from a primary power supply line on the road side where the moving body moves via a power supply transformer. On the side of the moving body that receives power in a contactless manner, in addition to the main circuit for supplying power to the power, a control power supply that supplies stabilized power to a control circuit or a protection circuit is sometimes prepared. Even in various situations that may occur during contactless power supply, these control power supplies are required to supply power to the control circuit or the protection circuit stably or to the minimum necessary. In the case of a circuit that is expected to ensure fail-safe operation in the event of a failure, such as a protection circuit, it is extremely important to ensure power supply. Summary of the invention

[0004] However, the power receiving side in the contactless power supply system often has a circuit structure that cuts off the power supply to ensure safety between the power receiving part such as the power receiving coil that receives power in a contactless manner and the power supply circuit. For example, in the case of a structure in which the side that receives power in a contactless manner includes a power storage device such as a battery, and power is supplied to the entire device after temporarily accumulating power in the battery through contactless power supply, the purpose of the contactless power supply is to charge the battery, and most of them are configured as a constant current circuit. In this case, when the load side of the battery is opened and the impedance becomes high, an overvoltage will be generated. In order to avoid such a problem, control is introduced, and there is a problem of how to ensure the power supply for performing the control. This problem is not limited to mobile objects, but is the same in the power receiving device that supplies the main power to the load device.

[0005] (1) A first aspect of the present disclosure is an aspect of a power receiving device that receives power supply in a non-contact manner. The power receiving device includes: a power receiving coil that receives AC power from the outside in a non-contact manner using magnetic field coupling; a first power supply unit that includes a rectifier circuit that rectifies the AC power received by the power receiving coil and converts it into DC power, and supplies main power used in a load device; and a second power supply unit that is connected to a preceding stage of the first power supply unit and outputs power used for controlling the first power supply unit in the form of DC power.

[0006] (2) Another aspect of the present disclosure is an aspect of a contactless power supply system, the contactless power supply system including: such a power receiving device; and a power transmitting device, the power transmitting device having a power transmitting coil, the power transmitting coil being magnetically coupled to the power receiving coil when the power receiving coil of the power receiving device approaches, and supplying the AC power to the power receiving coil.

[0007] (3) In addition, another aspect of the present disclosure is an aspect as a contactless power supply method. The contactless power supply method applies an AC voltage to a power transmission coil provided in a power transmission device, rectifies the AC electromagnetically induced in the power receiving coil at a position capable of coupling with the magnetic field of the power transmission coil by a rectifier circuit and converts it into a DC, supplies the DC as the main power of the load device for use, and receives power supply from a preceding stage of the rectifier circuit, outputs power smaller than the main power in the form of a DC as power for controlling the main power.

[0008] According to these methods, it is possible to receive power supply from the front stage of the rectifier circuit that supplies the main power to the load device, and obtain power smaller than the main power in direct current, and use it for the control of the main power. Therefore, even if a circuit using the main power fails, or the supply of the main power is stopped due to a failure on the side supplying the main power, the control related to the output of the main power can be continued. In addition, the present disclosure can be implemented in various ways, for example, in addition to the power supply device, it can also be implemented in various ways such as a design method of a power receiving system. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] 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 5A 1 is a schematic structural diagram of a power receiving device including a first power supply unit. Figure 5B It is a schematic structural diagram showing another structural example of the power receiving device. Figure 6 1 is a circuit configuration diagram showing a first 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 7 1 is a circuit configuration diagram showing a second configuration example of the DC power supply unit and the second power supply unit. Figure 8 1 is a circuit configuration diagram showing a third configuration example of the DC power supply unit and the second power supply unit. Fig. 9 1 is a circuit configuration diagram showing a fourth configuration example of the DC power supply unit and the second power supply unit. Fig.10 This is a circuit configuration diagram showing an example of connection between a first power supply unit and a second power supply unit when the power receiving device includes a transient filter. Fig.11 1 is a circuit configuration diagram showing another configuration example of the connection between the first power supply unit and the second power supply unit. Fig.12 1 is a circuit configuration diagram showing another configuration example of the connection between the first power supply unit and the second power supply unit. Fig.13 This is a circuit configuration diagram illustrating a configuration in which the output of the first power supply unit is short-circuited using the power of the second power supply unit. Fig.14 1 is a circuit configuration diagram showing another configuration in which the output of the first power supply unit is short-circuited using the power of the second power supply unit. Fig.15 1 is a circuit configuration diagram showing another configuration in which the output of the first power supply unit is short-circuited using the power of the second power supply unit. DETAILED DESCRIPTION

[0010] A. First Implementation Method: (A1) Overall structure of the contactless power supply system: Figure 1The schematic structure of the contactless power supply system 100 including the power receiving device 30 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 the power receiving device 30 built in the mobile body 20 that automatically travels on the road surface RS. The mobile body 20 includes a driving wheel 21 driven by a motor (not shown) included in the load device 45, a driven wheel 22 that supports the mobile body 20 on the road surface RS in a movable manner together with the driving wheel 21, a power receiving coil 31 arranged under the bottom plate of the mobile 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, converts it into DC by the first power supply unit 41 and the second power supply unit 42 provided in the power receiving device 30, and in particular supplies power from the first power supply unit 41 to the load device 45. The power supplied by the first power supply unit 41 is the main power used at least in the mobile body 20. The second power supply unit 42 outputs power for controlling the first power supply unit 41 in direct current. 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 a 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.

[0011] The plurality of power transmission devices 50 that supply power to the power receiving device 30 of the moving body 20 respectively include the same structure and are arranged along the moving path of the moving body 20. Of course, the power transmission devices 50 are not limited to the moving path of the moving 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 structure is different.

[0012] The main power supply device 70 receives a supply of low-frequency (eg, 60 Hz) alternating current from the main power supply 80 , and converts the supply into high-frequency alternating current. Figure 2An example of the circuit structure of the main power supply device 70 is shown. 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 from the side receiving power from the main power supply 80. 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 80 is converted into the AC of the above frequency by the inverter 73 and output to the main power line RFP.

[0013] Each power transmission device 50 operates by receiving power from the main power line RFP. Figure 1 As shown, each power transmission device 50 forms a resonance circuit by a power transmission coil 51 and a resonance capacitor 52, and an impedance circuit 55 is installed between the resonance capacitor 52 and the main power line RFP. The impedance circuit 55 is a circuit that controls the supply of high-frequency power from the main power line RFP to the resonance circuit. Equivalently, in this embodiment, it is a relay or a switch element that cuts off the supply of high-frequency power. Each power transmission device 50 also includes a control circuit 58 that controls the impedance circuit 55, a Hall element 57 that is a magnetic sensor for detecting the presence of the moving body 20, and a DC power supply unit 60 that supplies DC power for operation to the control circuit 58. The detailed description of the power transmission device 50 will be described later, but not all power transmission devices 50 are always in operation, but only the power transmission device 50 that the moving body 20 approaches is in operation. In this embodiment, the approach of the moving body 20 is detected by detecting the magnetic force of the magnet 24 provided on the moving body 20 by the Hall element 57. When the approach of the moving body 20 is detected, the control circuit 58 changes the impedance of the impedance circuit 55, that is, if the impedance circuit 55 is a circuit structure that can be turned on and off, when the approach of the moving body 20 is detected, the impedance circuit 55 is turned on (conducted), and when the moving body 20 leaves the range where the power can be received from the power transmission coil 51, the impedance circuit 55 is turned off (cut off). The detection of the approach and departure of the moving body 20 can also be carried out by other methods, such as a structure that detects the change in mutual inductance caused by the approach of the power receiving coil 31 to the power transmission coil 51. In addition, the power transmission device 50 that is in operation is not limited to one, and two or more power transmission devices 50 that the moving body 20 approaches can also be operated.

[0014] Figure 3Schematic configurations of a power transmission device 50 and a power receiving device 30 are 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 object 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 through the power receiving coil 31. 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 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 object 20, it includes devices that use the main power used in the mobile object, such as the motor 48 for moving the mobile object 20. In addition, a battery that temporarily stores power may also be included in the load device 45.

[0015] 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.

[0016] 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 80, 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 52 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 .

[0017] On the other hand, the power receiving device 30 of the moving body 20 efficiently receives the induced current generated in the power receiving coil 31 magnetically coupled with the power transmitting coil 51 through the power receiving side resonance circuit 33, and supplies it 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, 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.

[0018] (A2) Structure and operation of the DC power supply unit and the second power supply unit: The specific structures and operations 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 are described. Figure 4 As shown in the example, the operating voltage is supplied to the control circuit 58 and the like included in the power transmission device 50. Figure 4 In the example shown, the control circuit 58 is connected to the Hall element 57, and detects the approach of the moving body 20 by detecting the magnetic force of the magnet 24 provided on the moving body 20, thereby driving the impedance circuit 55. The power for the operation of the control circuit 58 is provided by a low-voltage DC power supply. The DC power supply unit 60 supplies the low voltage DC (here 5V). The DC power supply unit 60 receives power supply from the main power line RFP, but since the main power line RFP is a high-voltage and high-frequency line, it is generally known that a structure is used to step down the voltage using a transformer and perform rectification to obtain a DC low-voltage output. In this embodiment, components that are easy to enlarge, such as transformers, are not used. Instead, a DC power supply unit 60 is used. Figure 6 The circuit structure described later will be described later.

[0019] On the other hand, in the present embodiment, the same circuit configuration is also adopted in the second power supply unit 42 on the power receiving device 30 side. In the power receiving device 30, the voltage induced in the power receiving coil 31 is also high voltage and high frequency, and the main power used in the moving body 20 is generated by the first power supply unit 41 and supplied to the load device 45, while the DC low voltage used by the power receiving device 30 itself is supplied by the second power supply unit 42. Figure 5AThe circuit structure inside the mobile body 20 with the power receiving device 30 as the center is illustrated. In this embodiment, the power receiving side resonance circuit 33 of the power receiving device 30 includes a resonance capacitor RC connected in series. The rectifier circuit 34 that receives the AC output of the power receiving side resonance circuit 33 is configured as a synchronous rectifier using four switching elements SW, and converts the AC into DC by exclusively turning on and off the pairs of switching elements arranged at diagonal positions in the figure in synchronization with the alternation of voltage. A smoothing capacitor 39 is connected in parallel to the output of the rectifier circuit 34 to reduce the ripple after rectification and supply DC power to the load device 45. This is equivalent to the operation of the first power supply unit 41. In addition, in addition to the inverter 46 or the moving motor 48 driven by its output, a battery 47 and the like are also provided inside the load device 45.

[0020] The second power supply unit 42 receives AC power from the connection point between the power receiving coil 31 and the power receiving side resonance circuit 33, converts it into a DC low voltage internally, and outputs it to the drive control circuit 44. The drive control circuit 44 performs on / off control of the switch element SW of the rectifier circuit 34 configured as the above-mentioned rectifier. Figure 5B As shown, the second power supply unit 42 may receive power supply from the downstream side of the resonance capacitor RC constituting the power receiving side resonance circuit 33 , that is, from the rectifier circuit 34 side. Figure 5A , 5B The drive control circuit 44 shown is Figure 3 A specific example of the control circuit 43 is shown.

[0021] [1] First circuit configuration example: Hereinafter, four embodiments will be described in order with respect to the configurations of the DC power supply unit 60 of the power transmission device 50 and the second power supply unit 42 of the power reception device 30 . Figure 6 1 is a circuit diagram showing the circuit configuration of a DC power supply unit 60A and a second power supply unit 42A as a first configuration example. The circuit inputs a high-frequency, high-voltage AC voltage ACP and outputs a DC low voltage DCP. As the DC power supply unit 60A, the input is a high-frequency, high-voltage from the main power line RFP, and for the second power supply unit 42A, it is a high-frequency, high-voltage AC induced in the power receiving coil 31.

[0022] Insulating capacitors CC1 and CC2 are installed in series in the two power lines LN1 and LN2 of the circuit, respectively, and a protective diode PD1 is connected in parallel on 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 on the output sides of the two diodes PD1 and PD2. A circuit including at least the rectifying diode RD1 is called a rectifying unit RE, and a circuit including the Zener diode TzD and the smoothing capacitor CF is called a stabilized power supply unit SP. The rectifying unit RE sometimes includes a protective diode PD1 or a non-return diode PD2. In addition, although not specifically shown in the figure, this is not particularly useful. Figure 7 to Figure 9 The same is true in .

[0023] The DC power supply unit 60A and the second power supply unit 42A 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 60A and the second power supply unit 42A are connected to the high-frequency, high-voltage AC voltage ACP, the current corresponding to the charge accumulated in the insulating capacitors CC1 and CC2 does not flow through the power supply lines LN1 and LN2 during one cycle of the AC, and therefore, the amount of power output by the circuit can be easily adjusted using the capacitance of the insulating capacitors CC1 and CC2. If the amount of power handled by the DC power supply unit 60A and the second power supply unit 42A is small, that is, the capacitance can be reduced, it is possible to use capacitors with a higher withstand voltage, such as ceramic capacitors, as the insulating capacitors CC1 and CC2 instead of using more film capacitors and other capacitors with a lower withstand voltage in the power supply circuit, which can be easily achieved even when the AC voltage ACP is high.

[0024] Moreover, by using 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 60A and the second power supply unit 42A, 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 60A and the second power supply unit 42A can be reduced. In addition, there is no need for step-down components such as transformers that step down the voltage from a high voltage, and the circuit can be constructed to be small. Moreover, 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.

[0025] [2] Second configuration example of the circuit: Next, use Figure 7 1 and 2 are used to illustrate a second configuration example of the DC power supply unit 60 and the second power supply unit 42. FIG. 2 is a circuit diagram showing the circuit configuration of the DC power supply unit 60B and the second power supply unit 42B. The second configuration example is different from the first configuration example ( Figure 6 ) are the same except that the non-return diode PD2 is not included. In the DC power supply unit 60B and the second power supply unit 42B of the second structural example, since the non-return diode PD2 does not exist, the circuit structure can be simplified accordingly. In addition, since the forward direction reduction voltage caused by the non-return diode PD2 does not occur, the DC low voltage DCP can be increased accordingly. Other effects are the same as those of the first structural example.

[0026] [3] The third circuit configuration example: Next, use Figure 8 1 and 2 are used to illustrate a third configuration example of the DC power supply unit 60 and the second power supply unit 42. FIG. 2 is a circuit diagram showing the circuit configuration of the DC power supply unit 60C and the second power supply unit 42C. Figure 7 ) is the same except that the insulating capacitor CC2 is not included. According to the third configuration example, in addition to being able to achieve the same effects as the second configuration example, the power supply line LN2 can be used as the ground potential of the DC low voltage DCP.

[0027] [4] Fourth circuit configuration example: Next, use Fig. 9 4. The fourth configuration example of the DC power supply unit 60 and the second power supply unit 42 is described. FIG. 4 is a circuit diagram showing the circuit configuration of the DC power supply unit 60D and the second power supply unit 42D. Figure 6 and Figure 7 ) is compared with the fourth structural example, except that it includes four rectifier diodes RD1 to RD4 that constitute a diode bridge for full-wave rectification.

[0028] In this circuit structure, compared with the first to third structural examples, which convert AC to DC through half-wave rectification, the conversion efficiency can be almost doubled through full-wave rectification. Therefore, the capacity of the insulating capacitors CC1 and CC2 can be reduced. The circuit structure can be miniaturized, and high efficiency can be achieved due to the lack of loss. Other effects are the same as those of the first to third structural examples.

[0029] According to the power receiving device 30 of the first embodiment described above, it is not necessary to supply part of the power supplied to the load device 45 to the control device that controls the first power supply unit 41, which has the effect of simplifying the power structure on the mobile body 20 side. In addition, as shown in the first to fourth configuration examples, the structure of the second power supply unit 42 does not require the use of a transformer or the like for voltage reduction and insulation of the power line, and the second power supply unit 42 can be realized with a simple structure, and it is also easy to achieve miniaturization. In addition, the efficiency of the circuit that supplies power can be improved.

[0030] On the other hand, according to the power transmission system 200 including the power transmission device 50 that performs contactless power supply in the first embodiment, a DC voltage as a power supply voltage of a control circuit included in the power transmission device 50 can be generated inside the power transmission device 50. Therefore, it is not necessary to lay a power supply line for supplying a DC voltage to each power transmission device 50 other than the main power line RFP, and the laying performance and handling of the power transmission system can be improved. Moreover, as shown in the first to fourth structural examples, the structure of the DC power supply unit 60 does not require the use of a transformer for voltage reduction and power line insulation, and the DC power supply unit 60 can be implemented with a simple structure, and it is also easy to achieve miniaturization. In addition, the efficiency of the circuit that supplies power can be improved.

[0031] B. Second Implementation Method: Next, a power receiving device 30A according to a second embodiment will be described. Fig.10 : is a schematic structural diagram showing the structure of the power receiving device 30A of the second embodiment. Unlike the first embodiment, the power receiving device 30A has resonance capacitors RC1 and RC2 at both ends of the power receiving coil 31 as a power receiving side resonance circuit 33A, and has a transient filter 35 between the power receiving side resonance circuit 33A and the rectifier circuit 34 at the subsequent stage. The power receiving side resonance circuit 33A adopts a circuit structure that becomes a voltage source output. By providing the transient filter 35 at the output of the power receiving side resonance circuit 33A, it can be output as a current source. Generally speaking, when charging a battery, a current source output is used. The transient filter 35 of this embodiment is composed of four inductors L1 to L4 and a capacitor CI. Of course, in addition to the T-LCL type, a π-CLC type or a T-LCLC type transient filter can also be used.

[0032] In the second embodiment, compared with the first embodiment, the transient filter 35 is provided between the power receiving side resonance circuit 33A and the rectifier circuit 34, and the power is supplied to the second power supply unit 42 from the connection point between the power receiving coil 31 and the power receiving side resonance circuit 33 but from the connection point between the power receiving side resonance circuit 33 and the transient filter 35 at the subsequent stage. In the structure of the second embodiment, the same function and effect as the first embodiment are achieved. Therefore, in the second embodiment, even if the load device 45 side is opened and the power supply from the first power supply unit 41 is not performed, the power supply to the second power supply unit 42 continues, so various control devices that operate by receiving the power supply from the second power supply unit 42, such as the drive control circuit 44 shown in FIG. 5, remain in operation. Various circuits such as the drive control circuit 44 that operate by receiving the power supply from the second power supply unit 42 will be collectively described later.

[0033] The power supply location for supplying power to the second power supply unit 42 is not limited to Fig.10 The portion shown in FIG. 1 is a connection portion between the power receiving side resonance circuit 33 and the transient filter 35, for example, Fig.11 As shown in the power receiving device 30B of FIG. 1 , it does not matter whether the two ends of the capacitor CI in the transient filter 35 are connected. In addition, in the power receiving device, for example, Fig.12 As shown in the power receiving device 30C, the transient filter is configured to not include the reactors L1 and L2 inside. In the transient filter 35A shown in the figure, the reactors L1 and L2 are not included inside, and the leakage inductance of the power receiving coil 31 connected via the power receiving side resonance circuit 33A is used instead. In this way, the structure of the transient filter 35A can be simplified and it is also easy to achieve miniaturization.

[0034] C. Third Implementation Method: Next, a power receiving device 30D according to a third embodiment will be described. Fig.13 1 is a schematic structural diagram showing the structure of a power receiving device 30D according to the third embodiment. The power receiving device 30D includes the power receiving device 30D of the second embodiment. Fig.125 , and the two switching elements SL1 and SL2 of the lower arm 36 are driven by the drive control circuit 44 shown in FIG5 . The two switching elements SL1 and SL2 of the lower arm 36 are driven by the drive signal from the drive control circuit 44 and the drive signal from the cut-off control circuit 44A.

[0035] In the power receiving device 30D of the third embodiment including this circuit configuration, when a certain abnormality is detected in the first power supply unit 41 and the load device 45 serving as the load, a cutoff signal is output from the cutoff control circuit 44A to the two switch elements SL1 and SL2 of the lower arm 36, and the switch elements SL1 and SL2 are both driven to the on state. As a result, the power supply line LN1 and the power supply line LN2 of the first power supply unit 41 are substantially short-circuited, although there are on-resistances of the switch elements SL1 and SL2 on the output side of the transient filter 35A. The switch elements SL1 and SL2 turned on simultaneously by the cutoff control circuit 44A function as a protection circuit for the first power supply unit 41.

[0036] In this state, the power supply by the first power supply unit 41 is not performed, but the second power supply unit 42 receives the power supply from the connection point between the power receiving side resonance circuit 33A and the transient filter 35A, and thus can operate normally and supply the DC voltage required for the operation of the cut-off control circuit 44A to the cut-off control circuit 44A. Figures 10 to 13 In the transient filter shown in the figures, the voltage level at the input terminal or both ends of the capacitor CI is maintained at the same level when the current is normally output and when the output of the transient filter is in a short-circuited state and the protection circuit is activated. That is, when the switch elements SL1 and SL2 are simultaneously turned on and the protection circuit is activated, the input of the rectifier circuit 34A is 0 volts, so the first power supply unit 41 is maintained in a state of not outputting power. On the other hand, the voltage at both ends of the capacitor CI of the transient filter 35A is maintained in the same state as the normal state (a state where an AC voltage of a resonant frequency is applied), so the second power supply unit 42 can be connected to the rectifier circuit 34A by Figures 6 to 9 Any of the circuits shown or an equivalent circuit thereof receives the voltage and continues to supply a predetermined power to the cutoff control circuit 44A and the like.

[0037] In the power receiving device 30D of the third embodiment described above, when an abnormality occurs on the load device 45 side, by driving the switching elements SL1 and SL2 of the rectifier circuit 34 provided for rectification, the output of the first power supply unit 41 can be short-circuited, and the power supply from the first power supply unit 41 to the load device 45 can be stopped. Moreover, even in this state, the second power supply unit 42 can output a predetermined DC voltage to the outside, for example, to the drive control circuits 44A and 44B, similarly to the case where the first power supply unit 41 operates normally.

[0038] exist Fig.13 In the circuit configuration shown in FIG. 1 , in order to short-circuit the output of the transient filter 35A, the two switching elements SL1 and SL2 constituting the lower arm 36 of the rectifier circuit 34 are simultaneously turned on (conducting state). Fig.14 As shown in FIG. 1 , a dedicated short-circuit contact 37 may be provided and driven by the cut-off control circuit 44B. Such a short-circuit contact 37 can be easily realized by a relay or a switch element. In this circuit structure, when some abnormality occurs on the load device 45 side, the output of the first power supply unit 41 can be short-circuited, which plays a role similar to Fig.13 The circuit structure shown has the same effect.

[0039] D. Fourth Implementation Method: Next, a power receiving device 30E according to a fourth embodiment will be described. Fig.15 1 is a schematic structural diagram showing the structure of a power receiving device 30E according to a fourth embodiment. The power receiving device 30E includes the components of the second embodiment and the third embodiment. Fig.12 The transient filter 35A shown in FIG. 1 is the same in structure, but is different in that it includes a cutoff control circuit 44C that is operated by receiving the supply of DC power from the second power supply unit 42. Fig.15 The circuit configuration shown further includes a control circuit 49 for driving four switching elements of the rectifier circuit 34 to realize synchronous rectification. In this example, the control circuit 49 operates with a power supply voltage Vcc derived from a DC voltage supplied from the first power supply unit 41 to the load device 45 .

[0040] Two of the four drive signals output by the control circuit 49 are directly output to the gates of the switch elements SU1 and SU2, but the remaining two drive signals are input to one input terminal of the 2-input OR gates ORG1 and ORG2, and are output to the gates of the switch elements SL1 and SL2 via the OR gates ORG1 and ORG2. The 2-input OR gates ORG1 and ORG2 operate together with the cut-off control circuit 44C using the DC voltage from the second power supply unit 42 as a power supply. The output signal from the cut-off control circuit 44C is input to the other input terminal of the 2-input OR gates ORG1 and ORG2. The cut-off control circuit 44C has a built-in node gate NOT that takes the power supply voltage Vcc as an input, and the output of the node gate NOT becomes an output signal output to the 2-input OR gates ORG1 and ORG2. Therefore, when the power supply voltage Vcc derived from the load device 45 collapses and becomes 0 volts, the output signal of the cutoff control circuit 44C having the built-in node gate NOT becomes high level, and even if the output signal from the control circuit 49 becomes low level due to the collapse of the power supply voltage Vcc, the outputs of the two-input OR gates ORG1 and ORG2 become high level. As a result, the switch elements SL1 and SL2 become conductive, and the output voltage of the first power supply unit 41 can be cut off as in the third embodiment.

[0041] The power receiving device 30E of the fourth embodiment can disconnect the output of the first power supply unit 41 in the rectifier circuit 34 by operating the cut-off control circuit 44C and the 2-input OR gates ORG1 and ORG2 that supply power from the second power supply unit 42 when the power supplied to the control circuit 49 that drives the switching element of the rectifier circuit 34 and performs synchronous rectification. In order to realize such an operation, the power supplied by the second power supply unit 42 is only slightly small, and the output of the first power supply unit 41 in the rectifier circuit 34 is disconnected by operating the cut-off control circuit 44C and the 2-input OR gates ORG1 and ORG2 that supply power from ... only disconnected by operating the cut-off control circuit 44C and the 2-input OR gates ORG1 and ORG2 that supply power from the second power supply unit 42 is only disconnected by operating the cut-off control circuit 44C and the 2-input OR gates ORG1 and ORG2 that supply Figures 6 to 9 The simple structure of the second power supply unit 42 shown in the above figures can realize a practical circuit structure.

[0042] E. Other implementation methods: (1) One of the other embodiments is an embodiment of a power receiving device that receives power supply in a non-contact manner. The power receiving device includes: a power receiving coil that receives AC power from the outside in a non-contact manner using magnetic field coupling; a first power supply unit that includes a rectifier circuit that rectifies the AC power received by the power receiving coil and converts it into DC, and supplies main power used in a load device on the power receiving side; and a second power supply unit that is connected to the front stage of the first power supply unit and outputs power used for controlling the first power supply unit in the form of DC. In this way, since the power of the second power supply unit is obtained from the front stage of the first power supply unit, even if the first power supply unit fails or the power supply operation of the first power supply unit is stopped due to a failure on the side of the load device to which the first power supply unit supplies power, the second power supply unit can continue to supply power.

[0043] The power supplied by the first power supply unit is the main power used in the load device, for example, it is used to generate power for the movement of the load device. Alternatively, it is used as power for driving auxiliary equipment such as an air conditioner or a power generation device installed in the load device. In contrast, the power supplied by the second power supply unit is at least the power used for controlling the first power supply unit. As the control of the first power supply unit, there is, for example, the stop of the output of the first power supply unit, the cutting off of the output of the first power supply unit, or the operation of the protection circuit that protects the first power supply unit. The power supplied by the second power supply unit is used to implement these actions. Of course, the power of the second power supply unit can also be supplied to control circuits other than this. For example, it can also be used as power for emergency communications with the outside in an emergency, power for driving an emergency alarm sound generator, a warning light, etc., power for a backup power supply circuit of a recorder or memory installed in the load device, etc.

[0044] As the load device, various devices such as a power device such as a motor or a solenoid, a heat generating body such as a heater, a light emitting body such as a lamp, and a sound generating body such as a speaker can be adopted.

[0045] (2) In such a structure, the load device may be a device provided on a moving body. The moving body provided with the load device may be a four-wheeled car, a two-wheeled car, a large bus, a truck, or an unmanned vehicle such as an automatic guided vehicle. Of course, it may also be a moving body that moves without wheels, such as a hovercraft or a magnetically suspended linear electric vehicle. The power receiving coil that receives AC current from the outside in a non-contact manner using magnetic coupling may be housed inside the housing of the moving body, or may be exposed to the outside. The coil on the power transmission side that supplies power to the power receiving coil through magnetic coupling may be arranged or buried on the floor or road surface on which the moving body moves, but may also be arranged on a wall or ceiling. In the case where the moving body is a straddle-type monorail, power may be received and supplied through magnetic coupling within the track that restricts the movement of the moving body. The power receiving coil may be arranged in a manner close to and opposite to the power transmitting coil, or may be supplied with power with a relay coil sandwiched between the power transmitting coil. In this case, in the case where the moving body includes wheels such as tires, a structure in which the relay coil is arranged in the tire or its wheel hub may also be adopted. As the load device of the mobile body, various devices such as a motor for moving the mobile body, a unit motor, a heater or a compressor for air conditioning, various pumps, and electric components can be adopted.

[0046] (3) In such a structure, the filter unit may be a transient filter composed of a reactor and a capacitor. In this way, when the receiving coil and the resonant circuit are configured to function as a voltage source output, a current source output can be obtained by connecting a transient filter thereto. The transient filter is not limited to the T-LCL type, and various structures such as the π type may be used.

[0047] (4) In such a structure, the input side of the second power supply unit may be connected in parallel with the input side of the transient filter or the capacitor constituting the transient filter. In this way, even if a fault occurs in the rear stage of the rectifier circuit and the first power supply unit cannot supply power, the second power supply unit can receive the voltage across the capacitor of the transient filter and continue to supply power, and the first power supply unit using the power can be controlled. The input side of the second power supply unit may be connected to both ends of the receiving coil, and when the receiving coil is connected to the resonant circuit, it may be connected to the output side of the resonant circuit.

[0048] (5) In the structure of (3) or (4) above, a short-circuit circuit may be included in the front stage of the rectifier circuit of the first power supply unit, and the short-circuit circuit is controlled by the power output from the second power supply unit in direct current and cuts off the power supply to the rectifier circuit. In this way, the power supply from the first power supply unit can be cut off. In addition, if an appropriate filter unit using a transient filter or the like is provided in the front stage of the rectifier circuit, the power supply to the second power supply unit can continue even if the power supply is cut off using a short-circuit circuit. The short-circuit circuit can be implemented using a switching element or by a relay contact or the like.

[0049] (6) In the configuration of (3) or (4), the rectifier circuit of the first power supply unit may be a synchronous rectifier including a switching element, and short-circuit control may be performed to simultaneously turn on the switching element provided in one power line of the synchronous rectifier. In this way, short-circuit control can be implemented using a part of the rectifier circuit, which can reduce the circuit structure and save resources.

[0050] (7) In such a configuration, the second power supply unit may supply power sufficient to implement the short-circuit control. In this way, power shortage does not occur during the short-circuit control.

[0051] (8) In such a structure, an insulating capacitor is installed on at least one side of the power line connecting the above-mentioned receiving coil and the above-mentioned second power supply unit, and the above-mentioned second power supply unit includes a rectifying unit using a diode, a stabilizing power supply unit composed of a Zener diode connected in parallel with the above-mentioned power line and a smoothing capacitor. In this way, even if the AC voltage received by the receiving coil is separated from the DC voltage output by the second power supply unit, the DC voltage output by the second power supply unit can be obtained without using large components such as a step-down transformer. In addition, if an insulating capacitor is installed in all power lines, the second power supply unit can be insulated from the circuit from the receiving coil to the first power supply unit, and the noise resistance performance can be improved. The stabilizing power supply unit is not limited to a structure using a Zener diode, and it is also possible to adopt a circuit structure using a transistor, a three-terminal regulator that adjusts to a specified voltage output, etc.

[0052] (9) In such a structure, the rectifier can be a half-wave rectifier or a full-wave rectifier. In this way, an appropriate structure can be adopted according to the required power. If the power obtained by half-wave rectification is sufficient, the number of rectifier diodes can be reduced, which helps save resources.

[0053] (10) In such a configuration, the rectifying unit may include a diode mounted on one of the power lines and a non-return diode mounted on the other of the power lines. This can prevent backflow.

[0054] (11) One of the other embodiments of the present disclosure is a contactless power supply system. The contactless power supply system includes: a power receiving device as described in any one of (1) to (10) above; and a power transmitting device, wherein the power transmitting device includes a power transmitting coil, and when the power receiving coil of the power receiving device approaches, the power transmitting coil is magnetically coupled to the power receiving coil and supplies the AC power to the power receiving coil. In this way, a contactless power supply system can be easily implemented.

[0055] (12) In such a structure, the power transmission device may include a power transmission side resonance circuit composed of the power transmission coil and the power transmission capacitor, and the power receiving device may include a power receiving side resonance circuit composed of the power receiving coil and the power receiving capacitor, and the AC power may be received via the power receiving side resonance circuit, and the frequency of the AC power may be determined corresponding to the resonance frequencies of the power transmission side resonance circuit and the power receiving side resonance circuit. In this way, it is possible to realize highly efficient contactless power supply by utilizing resonance. Of course, the frequency of the AC power supply for receiving and supplying power does not need to be completely consistent with the resonance frequency that is the peak value of the resonance in the resonance circuit, and power transmission and reception may be performed at a frequency that deviates from the resonance frequency as long as it is within a range allowed by the design of the system. In addition, the power supply is not limited to the structure that receives power from only one power receiving device or one power transmission device on the load device side, and a structure that supplies power simultaneously from a plurality of power transmission devices may be adopted. In the above embodiment, it is described that a plurality of power transmission devices 50 are switched according to the approach of the mobile body 20 to perform power supply operation, but a power transmission device that always performs power supply operation may also be used.

[0056] (13) Another method disclosed in the present invention is a method of a contactless power supply method. The contactless power supply method applies an AC voltage to a power transmission coil provided in a power transmission device, rectifies the AC electromagnetically induced in the power receiving coil by a rectifier circuit at a position where the AC voltage can be coupled with the magnetic field of the power transmission coil, converts the AC voltage into a DC voltage, supplies the AC voltage to the load device on the power receiving side as the main power for use, receives power supply from the preceding stage of the rectifier circuit, and outputs a power smaller than the main power in the form of a DC voltage in order to control the main power. In this way, since the latter receives power from the preceding stage of the rectifier circuit, even if a circuit using the main power fails, or the supply of the main power is stopped due to a failure on the side supplying the main power, control related to the output of the main power can be continued.

[0057] (14) In each of the above embodiments, part of the structure implemented by hardware may be replaced by software. At least a part of the structure implemented by software may also be implemented by a discrete circuit structure. In addition, in the case where part or all of the functions of the present disclosure are implemented by software, the software (computer program) can be provided in the form of storage in a computer-readable recording medium. "Computer-readable 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 recording medium" has a broad meaning including any recording medium that can fix data packets rather than temporarily.

[0058] 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.

[0059] The control unit and method described in the present disclosure may also be implemented by a special-purpose computer, which is provided by constituting a processor and a memory, and the processor is programmed to perform 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 special-purpose computer, which is provided by constituting a processor by one or more special-purpose hardware logic circuits. Alternatively, the control unit and the method described in the present disclosure may be implemented by one or more special-purpose computers, which are composed of a processor and a memory programmed to perform one or more functions and a processor composed of 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 computers such as RAM or ROM, and external storage devices such as hard disks fixed to computers. That is, "computer-readable non-temporary tangible recording medium" has a broad meaning including any recording medium that can fix data packets rather than temporary.

Claims

1. A power receiving device, the power receiving device (30) receiving power supply in a non-contact manner, the power receiving device comprising: A power receiving coil (31) that receives AC power from the outside in a contactless manner using magnetic field coupling; a first power supply unit (41) including a rectifier circuit (34) for rectifying the AC power received by the power receiving coil and converting it into DC, and for supplying main power used in a load device; as well as A second power supply unit (42) is connected to a preceding stage of the first power supply unit and outputs power used for controlling the first power supply unit in the form of a direct current.

2. The power receiving device according to claim 1, wherein: The loading device is a device installed on the moving body (20).

3. The power receiving device according to claim 1, wherein: A filter unit is included between the power receiving coil and the rectifier circuit. The filter unit is a transient filter including reactors (L1-L4) and capacitors (CI).

4. The power receiving device according to claim 3, wherein: An input side of the second power supply unit is connected in parallel with an input side of the transient filter or the capacitor constituting the transient filter.

5. The power receiving device according to claim 3 or 4, characterized in that: A short circuit (37) is included at a preceding stage of the rectifier circuit of the first power supply unit. The short circuit is controlled by the power outputted from the second power supply unit in a direct current manner and cuts off the power supply to the rectifier circuit.

6. The power receiving device according to claim 3 or 4, characterized in that: The rectification circuit of the first power supply unit is a synchronous rectifier including switching elements, and short-circuit control is performed to turn on the switching elements (SL1, SL2) provided in one power supply line of the synchronous rectifier at the same time.

7. The power receiving device according to claim 6, wherein: The second power supply unit supplies power sufficient to implement the short-circuit control.

8. The power receiving device according to any one of claims 1 to 4, characterized in that: An insulating capacitor (CC1, CC2) is installed on at least one of the power lines connecting the power receiving coil and the second power supply unit. The second power supply unit includes, from upstream, a rectifier unit (RC) using diodes (RD1-RD4), and a stabilized power supply unit (SP) having a Zener diode (TzD) and a smoothing capacitor (CF) connected in parallel to the power line.

9. The power receiving device according to claim 8, wherein: The rectifier unit is configured as a half-wave rectifier or a full-wave rectifier.

10. The power receiving device according to claim 8, wherein: The rectifying unit includes a diode (RD1) mounted on one of the power lines and a non-return diode (PD2) mounted on the other of the power lines.

11. A contactless power supply system, comprising: The power receiving device according to any one of claims 1 to 4; as well as A power transmission device (50) includes a power transmission coil (51) which, when the power receiving coil of the power receiving device approaches, magnetically couples with the power receiving coil and supplies the AC power to the power receiving coil.

12. The contactless power supply system according to claim 11, characterized in that: The power transmission device includes a power transmission side resonance circuit (53), wherein the power transmission side resonance circuit has the power transmission coil and a power transmission capacitor (52). The power receiving device includes a power receiving side resonance circuit (33), and receives the AC power via the power receiving side resonance circuit. The power receiving side resonance circuit has the power receiving coil and a power receiving capacitor. The frequency of the AC power is determined in correspondence with the resonance frequencies of the power transmission-side resonance circuit and the power reception-side resonance circuit.

13. A non-contact power supply method, The contactless power supply method applies an AC voltage to a power transmission coil provided in a power transmission device. The alternating current electromagnetically induced in the power receiving coil at a position where it can be coupled with the magnetic field of the power transmitting coil is rectified by a rectifying circuit and converted into direct current, and used as the main power of the load device on the power receiving side. The power supply is received from the preceding stage of the rectifying circuit, and power smaller than the main power is output as a direct current to control the main power.

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