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

Abstract

To realize a non-contact power transmission system in which a power source for controlling a power transmission device is simplified.SOLUTION: A non-contact power transmission system 200 includes a plurality of power transmission devices 50 that can transmit power to a power reception device 30 in a non-contact manner. Each of the power transmission devices is installed within a movable range of a mobile body 20, and includes a power transmission coil 51 that transmits power to a power reception device of the mobile body in a non-contact manner. Each of the power transmission devices includes a main power source line RFP for supplying AC power of a first voltage that is for use in power transmission, and a DC power source unit 60 that receives supply of the AC power from the main power source line, and outputs power of a second voltage that is lower than the first voltage and is for use in internal control in the power transmission device.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a technology for non-contact power transmission.

Background Art

[0002] Conventionally, various non-contact power supply technologies have been proposed, such as non-contact power supply to a moving body in motion from a running surface. For example, Patent Document 1 discloses a configuration of non-contact power supply in which a moving body receives power supply from a primary power supply line on the road surface side through a power supply transformer. In this case, a large number of power transmission devices are arranged on the running surface of the moving body, and the power transmission device for power transmission is switched according to the position of the moving body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when trying to control the switching of power supply on and off from such a power transmission device, specifically, a power transmission coil, a control power supply is required. For this reason, it is necessary to prepare a power supply line for the control power supply in addition to the main power supply, which requires additional wiring and increases the man-hours for laying the power transmission device.

Means for Solving the Problems

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

[0006] (1) The first aspect of the present disclosure is an aspect as a non-contact power transmission system (200). This non-contact power transmission system includes a plurality of power transmission devices (50) provided within the movable range of a moving body (20), each power transmission device having a power transmission coil (51) for non-contact power transmission to a power reception device (30) of the moving body, a main power supply line (RFP) for supplying AC power of a first voltage used for the power transmission to the plurality of power transmission devices, and a DC power supply unit (60) that receives AC power supply from the main power supply line and outputs power of a second voltage that is lower than the first voltage and is used for control within the power transmission device.

[0007] (2) The second aspect of the present disclosure is an aspect as a non-contact power supply system (100). This non-contact power supply system includes a power reception device having a power reception coil provided inside a moving body, a plurality of power transmission devices provided within the movable range of the moving body, each power transmission device having a power transmission coil that magnetically couples with the power reception coil of the power reception device of the moving body for non-contact power transmission, a main power supply line for supplying AC power of a first voltage used for the power transmission to the plurality of power transmission devices, and a DC power supply unit that receives AC power supply from the main power supply line and outputs power of a second voltage that is lower than the first voltage and is used for control within the power transmission device.

[0008] (3) Further, the third aspect of the present disclosure is an aspect as a non-contact power supply method. This non-contact power supply method supplies AC power of a first voltage to a plurality of power transmission devices provided within the movable range of a moving body via a main power supply line, and a DC power supply unit that receives AC power supply from the main power supply line outputs power of a second voltage that is lower than the first voltage and is the operating voltage of a control unit within the power transmission device. With the control of the control unit, at least one of the plurality of power transmission devices supplies high-frequency AC power to a power transmission coil provided in the power transmission device using the AC power of the first voltage, and non-contact power transmission is performed to a power reception coil of a power reception device of the moving body via the power transmission coil.

[0009] According to these aspects, the DC power of the second voltage can be used for the control of the power transmission device, and the labor and man-hours for laying a plurality of power transmission devices can be reduced. Note that the present disclosure can be realized in various forms, and for example, it can be implemented in various aspects such as a power supply device and a design method of a power transmission system.

Brief Description of the Drawings

[0010]

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Embodiments for Carrying Out the Invention

[0011] A. First Embodiment: (A1) Overall Configuration of the Non - contact Power Supply System: The schematic configuration of the non-contact power supply system 100 including the power transmission device 50 of the first embodiment is shown in FIG. 1. As shown in the figure, this non-contact power supply system 100 is composed of a plurality of power transmission devices 50 buried in the ground under the road surface RS and a power reception device 30 mounted on a moving body 20 that travels on the road surface RS. The moving body 20 includes drive wheels 21 driven by a motor (not shown) included in the load device 45, driven wheels 22 that support the moving body 20 on the road surface RS together with the drive wheels 21, a power reception coil 31 disposed under the floor of the moving body 20, and a magnet 24 also disposed under the floor. The power reception coil 31 is magnetically coupled with the power transmission coil 51 of the power transmission device 50 prepared on the road surface RS side to receive supply of AC power, and this is converted to DC by a first power supply unit 41 and a second power supply unit 42 provided in the power reception device 30. In particular, power is supplied from the first power supply unit 41 to the load device 45. The power supplied by the first power supply unit 41 is at least the main power used by the moving body 20. The second power supply unit 42 outputs power used for control of the first power supply unit 41 as DC. In addition to being buried under the road surface RS, the power transmission device 50 can be installed on the road surface, on a wall surface, or on a ceiling. In such cases, the power reception device 30 may be arranged at a predetermined position within the moving body 20 corresponding to the installation location of the power transmission device 50. For example, if the power transmission device 50 is laid on a wall surface, the power reception device 30 may be arranged on the side surface of the moving body 20. Further, in accordance with the laying position of the power transmission device 50, the power reception device 30 may be moved inside the moving body 20, or a plurality of power reception devices 30 may be prepared in advance and switched for use.

[0012] The plurality of power transmission devices 50 that supply power to the power reception device 30 of the moving body 20 each have the same configuration and are arranged along the moving path of the moving body 20. Of course, the power transmission devices 50 may be arranged two-dimensionally on the road surface RS not limited to the moving path of the moving body 20. Each power transmission device 50 is connected to a common main power line RFP. High-frequency (for example, 85 KHz) AC power is supplied to the main power line RFP from the main power supply device 70. In the present embodiment, it is assumed that each power transmission device 50 has the same configuration. However, for example, the configurations may not be the same as long as power transmission is possible, such as alternately arranging power transmission coils 51 having different sizes.

[0013] The main power supply device 70 receives low-frequency (e.g., 60 Hz) AC power from the main power supply 80 and converts it into high-frequency AC power. An example of the circuit configuration of the main power supply device 70 is shown in FIG. 2. The main power supply device 70 includes, from the side that receives power from the main power supply 80, a noise filter 71 for AC output, a PFC circuit 72, an inverter 73, and a filter 74. The PFC circuit 72 is a well-known circuit that eliminates the phase difference between the input voltage and the output current generated by the filter 71, suppresses harmonics, and improves the power factor to approach 1. The power supplied from the main power supply 80 is converted into AC power of the above frequency by the inverter 73 and output to the main power line RFP. The voltage output to the main power line RFP corresponds to the first voltage.

[0014] Each power transmission device 50 operates by receiving power supply from the main power line RFP. As shown in FIG. 1, each power transmission device 50 forms a resonance circuit from a power transmission coil 51 and a resonance capacitor 52, and an impedance circuit 55 is interposed between this 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, and equivalently, in this embodiment, it is a relay or a switching element that turns on and off the supply of high-frequency power. Each power transmission device 50 also includes a control circuit 58 that controls this impedance circuit 55, a Hall element 57 that is a magnetic sensor for detecting the presence of the moving body 20, a DC power supply unit 60 that supplies operating DC power to the control circuit 58, and the like. Although a detailed description of the power transmission device 50 will be given later, not all power transmission devices 50 operate constantly. Only the power transmission device 50 that the moving body 20 approaches operates. In this embodiment, the approach of the moving body 20 is detected by the Hall element 57 detecting the magnetic force of the magnet 24 provided on the moving body 20. 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 has a circuit configuration 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 it can receive power from the power transmission coil 51, the impedance circuit 55 is turned off (cut off). For detecting the approach and departure of the moving body 20, other methods, for example, a configuration that detects a change in mutual inductance due to the approach of the power reception coil 31 to the power transmission coil 51 may be adopted. Also, the number of operating power transmission devices 50 is not limited to one, and two or more power transmission devices 50 that the moving body 20 is approaching may be made to operate.

[0015] The schematic configuration of the power transmission device 50 and the power reception device 30 is shown in FIG. 3. The figure shows a state in which one of the plurality of power transmission devices 50 supplies power to the power reception device 30 of the moving body 20. At this time, the power transmission coil 51 of the power transmission device 50 is magnetically coupled to the power reception coil 31 of the power reception device 30, and an induced current (alternating current) flows through the power reception coil 31. The power reception coil 31 efficiently receives power by means of a power reception side resonance circuit 33 provided in the first power supply unit 41. A rectification circuit 34 is provided downstream of the power reception side resonance circuit 33, and the power received by the power reception coil 31 is converted to direct current and output to the load device 45. Here, the load device 45 represents all those that use the power output by the first power supply unit 41. In the case of the moving body 20, it includes those that use the main power used in the moving body, such as the moving motor 48 of the moving body 20. Also, a battery that temporarily stores power may be included in the load device 45.

[0016] The second power supply unit 42 is a circuit that generates a small amount of direct current separately from the first power supply unit 41, and operates by receiving power supply from both ends of the power reception coil 31, that is, from a stage upstream of the power reception side resonance circuit 33. The direct current voltage output by the second power supply unit 42 is used by the control circuit 43 and the like. The configuration of the second power supply unit 42 and the specific circuit configuration of the control circuit 43 will be described together later.

[0017] Summarizing the above from the perspective of non-contact power supply, on the ground side, the power supply source is the main power supply 80. The main power supply device 70 installed on the ground side converts this main power supply 80 into high-frequency alternating current power and supplies it to the main power line RFP. Therefore, by simply laying the main power line RFP, power can be supplied to the plurality of power transmission devices 50 arranged below the road surface RS. Of course, there may be cases where a communication line for exchanging information with the power transmission device 50 is laid, but as a power supply line, the main power line RFP is sufficient. In the power transmission device 50, as shown in FIG. 4, power is supplied to the moving body 20 in a non-contact manner via a resonance circuit 53 composed of a resonance capacitor 52 and a power transmission coil 51, and the necessary direct current power within the power transmission device 50 is provided by the direct current power supply unit 60. The voltage of the direct current power supplied from the direct current power supply unit 60 to the control circuit 58 corresponds to the second voltage.

[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 to the power transmission 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 described above refers to this configuration in which power is supplied 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 described above. 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 is achieved by the power supplied only from the main power line RFP, including the power required by the power transmission device 50.

[0019] (A2) Configuration 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 receiving device 30 will be described. As described above, the DC power supply unit 60 of the power transmission device 50 provides DC power of the second voltage as its operating voltage to the control circuit 58 included in the power transmission device 50, as illustrated in FIG. 4. In the example shown in FIG. 4, the control circuit 58 is connected to the Hall element 57 and drives the impedance circuit 55 by detecting the magnetic force of the magnet 24 provided on the moving body 20 for the approach of the moving body 20. The power for the operation of this control circuit 58 is supplied by a DC low voltage power supply. The DC power supply unit 60 supplies a second voltage (here, 5V) lower than the first voltage output from the main power line RFP. The DC power supply unit 60 receives power supply from the main power line RFP. However, since the main power line RFP is a high voltage and high frequency, generally, a configuration is known in which the voltage is stepped down using a transformer and then rectified to obtain a DC low voltage output. In the present embodiment, components such as transformers that are likely to be large-sized are not adopted, and the circuit configuration described later with reference to FIG. 6 and below is adopted.

[0020] 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 as well, the voltage induced in the power receiving coil 31 is a high voltage and high frequency, and while 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, the DC low voltage used in the power receiving device 30 itself is supplied by the second power supply unit 42. One of the circuit configurations inside the moving body 20 centered on the power receiving device 30 is illustrated in FIG. 5A. 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 by exclusively turning on and off in units of pairs of switching elements arranged at diagonal positions in the figure in synchronization with the alternation of the voltage, it converts AC to DC. 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 corresponds to the function of the first power supply unit 41. In addition, inside the load device 45, in addition to the inverter 46 and the moving motor 48 driven by its output, a battery 47 and the like are also provided. As illustrated in FIG. 5B, in the synchronous rectifier 34A, the upper arm may be formed by diodes D1 and D2, and only the lower arm may be formed by switching elements SV1 and SV2. The configurations of the upper arm and the lower arm may be reversed.

[0021] The second power supply unit 42 receives the supply of AC power from the connection point between the power receiving coil 31 and the power receiving side resonance circuit 33, converts it to a DC low voltage inside, and outputs this to the drive control circuit 44. The drive control circuit 44 performs rectification control to turn on and off the switching element SW of the rectifier circuit 34 configured as the above-described synchronous rectifier. The drive control circuit 44 is a specific example of the control circuit 43 shown in FIG. 3.

[0022] [1] First Configuration Example of Circuit Regarding 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 described above, four embodiments will be sequentially described below. FIG. 6 is a circuit diagram showing the circuit configurations of the DC power supply unit 60A and the second power supply unit 42A as a first configuration example. This circuit inputs a high-frequency and high-voltage AC voltage ACP and outputs a DC low voltage DCP. The input of the DC power supply unit 60A is a high-frequency and high-voltage from the main power line RFP, and for the second power supply unit 42A, it is a high-frequency and high-voltage AC induced in the power reception coil 31.

[0023] Insulating capacitors CC1 and CC2 are serially interposed in each of the two power lines LN1 and LN2 of this circuit, and a protection 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 to the output side of the insulating capacitor CC1, and a blocking diode PD2 is connected in series in the reverse direction to 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 both diodes PD1 and PD2. A circuit including at least the rectifying diode RD1 is sometimes referred to as a rectifying section RE, and a circuit including the Zener diode TzD and the smoothing capacitor CF is sometimes referred to as a stabilized power supply section SP. The rectifying section RE may include the protection diode PD1 and the blocking diode PD2. Although not particularly shown, this is the same in FIGS. 7 to 9.

[0024] The DC power supply unit 60A and the second power supply unit 42A having such a circuit configuration are insulated from the high-frequency and high-voltage AC voltage ACP by the insulating capacitors CC1 and CC2. According to the change of the AC voltage ACP, an alternating voltage is generated between the two power lines LN1 and LN2. Among this alternating voltage, only when the power line LN1 side becomes higher in potential than the other power line LN2, the charges accumulated in the insulating capacitors CC1 and CC2 are used to charge the smoothing capacitor CF through the rectifying diode RD1. However, the part of the alternating voltage that exceeds the Zener breakdown voltage (hereinafter simply referred to as the Zener voltage) of the Zener diode TzD flows through the Zener diode TzD and is recovered through the reverse-blocking diode PD2. Therefore, the potential difference across the smoothing capacitor CF does not exceed the Zener voltage of the Zener diode TzD. Accordingly, the DC low voltage DCP is maintained at the Zener voltage. When the AC voltage ACP is inverted, the power line LN1 side and the power line LN2 side are maintained at a potential difference corresponding to the forward voltage drop of the protection diode PD1, so it has no effect on the smoothing capacitor CF. The DC power supply unit 60A and the second power supply unit 42A are connected to the high-frequency and high-voltage AC voltage ACP. However, since only the current corresponding to the charges accumulated in the insulating capacitors CC1 and CC2 in one cycle of the alternating current flows through the power lines LN1 and LN2, the amount of power output by the circuit can be easily adjusted by 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, if the capacitance can be made small, capacitors with a high breakdown voltage such as ceramic capacitors can be used as the insulating capacitors CC1 and CC2 instead of capacitors with a low breakdown voltage such as film capacitors that are often used in power circuits, and it can be easily realized even when the AC voltage ACP is high.

[0025] Moreover, the insulating capacitors CC1 and CC2 can easily separate the DC power supply units 60A and the second power supply unit 42A from the side supplying the AC voltage ACP, that is, the main power line RFP and the power lines of the first power supply unit 41, and can be less affected by noise and the like. As a result, the possibility of malfunction of a control circuit or the like using the DC power supply units 60A and the second power supply unit 42A can be reduced. Also, there is no need for a step-down component such as a transformer for stepping down from a high voltage, and the circuit can be configured in a small size. Furthermore, since no resistor is used in the circuit configuration, there is no loss due to the resistor, and the efficiency of the circuit can be increased.

[0026] [2] Second configuration example of the circuit: Next, a second configuration example of the DC power supply unit 60 and the second power supply unit 42 will be described with reference to FIG. 7. The figure is a circuit diagram showing the circuit configurations of the DC power supply unit 60B and the second power supply unit 42B. The second configuration example is the same as the first configuration example (FIG. 6) except that it does not include the reverse blocking diode PD2. In the DC power supply unit 60B and the second power supply unit 42B of the second configuration example, the circuit configuration can be simplified because the reverse blocking diode PD2 does not exist. Also, since the forward voltage drop due to the reverse blocking diode PD2 does not occur, the DC low voltage DCP can be made higher by that amount. Other operational effects are the same as those of the first configuration example.

[0027] [3] Third configuration example of the circuit: Next, a third configuration example of the DC power supply unit 60 and the second power supply unit 42 will be described with reference to FIG. 8. The figure is a circuit diagram showing the circuit configurations of the DC power supply unit 60C and the second power supply unit 42C. The third configuration example is the same as the second configuration example (FIG. 7) except that it does not include the insulating capacitor CC2. According to the third configuration example, the same operational effects as those of the second configuration example are achieved, and the power line LN2 can be used as the ground potential of the DC low voltage DCP.

[0028] [4] Fourth configuration example of the circuit: Next, a fourth configuration example of the DC power supply unit 60 and the second power supply unit 42 will be described with reference to FIG. 9. The figure is a circuit diagram showing the circuit configurations of the DC power supply unit 60D and the second power supply unit 42D. The fourth configuration example has the same configuration as the first and second configuration examples (FIGS. 6 and 7), except that it includes four rectifying diodes RD1 to RD4 that form a diode bridge for full-wave rectification.

[0029] In this circuit configuration, compared with the first to third configuration examples where the AC is converted to DC by half-wave rectification, the conversion efficiency can be almost doubled by performing full-wave rectification. Therefore, the capacitances of the insulating capacitors CC1 and CC2 can be reduced. Other operational effects, such as being able to be miniaturized and realizing high efficiency due to no loss, are the same as those of the first to third configuration examples.

[0030] According to the power receiving device 30 of the first embodiment described above, there is an effect that it is not necessary to supply a part of the power supplied to the load device 45 to the control device that controls the first power supply unit 41, and the power configuration on the moving body 20 side can be simplified. Moreover, as shown in the first to fourth configuration examples of the configuration of the second power supply unit 42, it is not necessary to use a transformer or the like for step-down and insulation of the power line, and the second power supply unit 42 can be realized with a simple configuration, and it is also easy to achieve miniaturization. Furthermore, the efficiency of the circuit for supplying power can be increased.

[0031] On the other hand, according to the power transmission system 200 including the power transmission device 50 that performs non-contact power supply in the first embodiment, a DC voltage as the power supply voltage of the 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 the DC voltage to each power transmission device 50 separately from the main power line RFP, and the laying property and handling of the power transmission system can be improved. Moreover, as shown in the first to fourth configuration examples of the configuration of the DC power supply unit 60, it is not necessary to use a transformer or the like for step-down and insulation of the power line, and the DC power supply unit 60 can be realized with a simple configuration, and it is also easy to achieve miniaturization. Furthermore, the efficiency of the circuit for supplying power can be increased.

[0032] B. Second Embodiment: Next, a power receiving device 30A that constitutes a non-contact power supply system as the second embodiment will be described. FIG. 10 is a schematic configuration diagram showing the configuration of the power receiving device 30A of the second embodiment. Different from the first embodiment, the power receiving device 30A includes resonance capacitors RC1 and RC2 at both ends of the power receiving coil 31 as a power receiving side resonance circuit 33A, and an impedance filter 35 is provided between the power receiving side resonance circuit 33A and the subsequent rectifier circuit 34. The power receiving side resonance circuit 33A adopts a circuit configuration with a voltage source output, and by providing an impedance filter 35 at the output of the power receiving side resonance circuit 33A, it is made into a current source output. Generally, when charging a battery, a current source output is used. The impedance filter 35 of this embodiment consists of four reactors L1 to L4 and a capacitor CI. Of course, in addition to the T-LCL type, it is also possible to use a π-CLC type or T-LCLC type impedance filter.

[0033] In the second embodiment, compared with the first embodiment, an impedance filter 35 is provided between the power receiving side resonance circuit 33A and the rectifier circuit 34, and the power supply to the second power supply unit 42 is taken from the connection point between the power receiving side resonance circuit 33 and the subsequent impedance filter 35, rather than from the connection point between the power receiving coil 31 and the power receiving side resonance circuit 33. Even with this configuration of the second embodiment, the same operational effects as those of the first embodiment are achieved. Therefore, also in the second embodiment, even if the load device 45 side is opened and the power supply from the first power supply unit 41 stops, the power supply to the second power supply unit 42 continues. Thus, various control devices that operate using the power supply from the second power supply unit 42, for example, the drive control circuit 44 shown in FIG. 5, continue to operate. Various circuits such as the drive control circuit 44 that operate using the power supply from the second power supply unit 42 will be described together later.

[0034] The power supply point to the second power supply unit 42 is not limited to the point shown in FIG. 10, that is, the connection point between the power receiving side resonance circuit 33 and the impedance filter 35. For example, as shown in FIG. 11 as the power receiving device 30B, it may be both ends of the capacitor CI in the impedance filter 35. Further, in the power receiving device, the impedance filter may be configured not to include the reactors L1 and L2 inside, as shown in FIG. 12 as the power receiving device 30C. In the illustrated impedance filter 35A, the reactors L1 and L2 are not provided inside, and the leakage inductance of the power receiving coil 31 connected via the power receiving side resonance circuit 33A is used instead. By doing so, the configuration of the impedance filter 35A can be simplified, and it is also easy to achieve miniaturization.

[0035] C. Third Embodiment: Next, the power receiving device 30D constituting the non-contact power supply system as the third embodiment will be described. FIG. 13 is a schematic configuration diagram showing the configuration of the power receiving device 30D of the third embodiment. This power receiving device 30D is the same in that it has the configuration of the impedance filter 35A shown in FIG. 12 as the second embodiment, and is different in that it includes a cutoff control circuit 44A that receives supply of DC power from the second power supply unit 42. This cutoff control circuit 44A drives two switching elements SL1 and SL2 that constitute a so-called lower arm 36 among the four switching elements provided in the rectifier circuit 34 that is a synchronous rectifier. Note that the four switching elements of the rectifier circuit 34 are configured to be driven by the drive control circuit 44 shown in FIG. 5 for both of the two switching elements SU1 and SU2 that constitute the upper arm, and the two switching elements SL1 and SL2 of the lower arm 36 are configured such that the drive signal from the drive control circuit 44 and the drive signal from the cutoff control circuit 44A are driven by a so-called wired OR.

[0036] In the power receiving device 30D of the third embodiment having such a circuit configuration, when it is detected that some abnormality has occurred in the first power supply unit 41 or the load device 45 which is its load, the cutoff control circuit 44A outputs a cutoff signal to the two switching elements SL1 and SL2 of the lower arm 36, and drives both the switching elements SL1 and SL2 into a conductive 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 at the output side of the impedance filter 35A, although there is an on-resistance of the switching elements SL1 and SL2. The switching elements SL1 and SL2 that are simultaneously turned on by the cutoff control circuit 44A function as a protection circuit for the first power supply unit 41.

[0037] In this state, power supply by the first power supply unit 41 is not performed, but since the second power supply unit 42 receives power supply from the connection point between the power receiving side resonance circuit 33A and the impedance filter 35A, it operates normally and supplies the cutoff control circuit 44A with the DC voltage necessary for the operation of the cutoff control circuit 44A. This is because, in the impedance filters shown in FIGS. 10 to 13, the voltage levels at the input terminals and both ends of the capacitor CI are maintained at approximately the same level whether the current is being output normally or the output of the impedance filter is short-circuited and the protection circuit is operating. That is, in the state where the switching elements SL1 and SL2 are simultaneously turned on and the protection circuit is functioning, the input of the rectifier circuit 34A becomes 0 volts, so the first power supply unit 41 is kept in a state of not outputting power, while the voltage across the capacitor CI of the impedance filter 35A is maintained in a state similar to the normal state (a state where an AC voltage at the resonance frequency is applied). Therefore, the second power supply unit 42 receives this voltage by one of the circuits shown in FIGS. 6 to 9 or an equivalent circuit thereof, and can continue to supply a predetermined amount of power to the cutoff control circuit 44A and the like.

[0038] 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 is short-circuited, and the power supply from the first power supply unit 41 to the load device 45 can be stopped. Moreover, even in that 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, in the same manner as when the first power supply unit 41 is operating normally.

[0039] In the circuit configuration shown in FIG. 13, in order to short-circuit the output of the impedance 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). However, as shown in FIG. 14, a dedicated short-circuit contact 37 may be provided and driven by the cutoff control circuit 44B. Such a short-circuit contact 37 can be easily realized by a relay or a switching element. Also in this circuit configuration, when some abnormality occurs on the load device 45 side or the like, the output of the first power supply unit 41 can be short-circuited, and the same operational effects as the circuit configuration shown in FIG. 13 can be obtained.

[0040] D. Fourth Embodiment: Next, a power receiving device 30E constituting a non-contact power supply system as a fourth embodiment will be described. FIG. 15 is a schematic configuration diagram showing the configuration of the power receiving device 30E of the fourth embodiment. This power receiving device 30E is the same in that it has the configuration of the impedance filter 35A shown in FIG. 12 as the second and third embodiments, and is different in that it includes a cutoff control circuit 44C that operates by receiving DC power supply from the second power supply unit 42. In the circuit configuration shown in FIG. 15, furthermore, a control circuit 49 for driving the four switching elements of the rectifier circuit 34 to realize synchronous rectification is provided. In this example, the control circuit 49 operates with a power supply voltage Vcc derived from the DC voltage supplied from the first power supply unit 41 to the load device 45.

[0041] Of the four drive signals output by this control circuit 49, two drive signals are directly output to the gates of the switching elements SU1 and SU2, while the remaining two drive signals are input to one input terminal of the two-input OR gates ORG1 and ORG2, and are output to the gates of the switching elements SL1 and SL2 via the OR gates ORG1 and ORG2. The two-input OR gates ORG1 and ORG2 both operate using the DC voltage from the second power supply unit 42 as a power source together with the cutoff control circuit 44C. An output signal from the cutoff control circuit 44C is input to the other input terminal of the two-input OR gates ORG1 and ORG2. The cutoff control circuit 44C incorporates a NOT gate NOT that takes the power supply voltage Vcc as an input, and the output of the NOT gate NOT is the output signal to the two-input OR gates ORG1 and ORG2. Therefore, when the power supply voltage Vcc derived from the load device 45 fails and becomes 0 volts, the output signal of the cutoff control circuit 44C incorporating the NOT gate NOT becomes high level, and even if the output signal from the control circuit 49 becomes low level due to the failure of the power supply voltage Vcc, the output of the two-input OR gates ORG1 and ORG2 becomes high level. As a result, the switching elements SL1 and SL2 become conductive, and similar to the third embodiment, the output voltage of the first power supply unit 41 can be turned off.

[0042] When the power supply to the control circuit 49 that drives the switching elements of the rectifier circuit 34 to perform synchronous rectification is lost in the power receiving device 30E of the fourth embodiment, due to the action of the cutoff control circuit 44C, the two-input OR gates ORG1 and ORG2 that are supplied with power from the second power supply unit 42, in the rectifier circuit 34, the output of the first power supply unit 41 can be turned off. To realize such an operation, only a small amount of power is required to be supplied by the second power supply unit 42, and a circuit configuration that can withstand practical use can be realized with the simple configuration of the second power supply unit 42 shown in FIGS. 6 to 9 and the like.

[0043] E. Fifth Embodiment: Next, the power transmission device 150 that constitutes the non-contact power supply system of the fifth embodiment will be described. As shown in FIG. 16, the power transmission device 150 operates by receiving power supply from the main power supply device 70, and includes a resonance circuit 53 composed of a power transmission coil 51 and a resonance capacitor 52, and an impedance circuit 55, similar to the power transmission device 50 of the first embodiment. The power transmission device 150 further includes a drive circuit 156 that drives the impedance circuit 55, a current sensor 157 that detects the current flowing through the resonance circuit 53, and a control unit 158 that controls the impedance circuit 55. The control unit 158 controls the impedance circuit 55 via the drive circuit 156 using the current value detected by the current sensor 157, and controls the current Ir flowing through the resonance circuit 53. Note that the drive circuit 156 and the current sensor 157 are each provided with a circuit that detects their respective operating voltages V1 and V2, and the drive circuit 156 and the current sensor 157 output the detected values of the operating voltages V1 and V2 to the control unit 158. The operating voltages V1 and V2 are those dealt with in the sixth embodiment described later, and in the fifth embodiment, it is not necessary to detect them.

[0044] The power supplies for each part of the power transmission device 150 have the following configuration. In this embodiment, since the operating voltages of the drive circuit 156, the current sensor 157, and the control unit 158 are different, three DC power supply units 160, 161, and 162 are provided. The configuration of each of the DC power supply units 160 to 162 may be any of the circuit configurations shown as Configuration Examples 1 to 3 of the DC power supply unit 60 in the first embodiment. The DC outputs of the DC power supply units 160 to 162 are the second voltage Vcc, and this voltage is the operating voltage of the control unit 158. On the other hand, the output of the DC power supply unit 161 is output to the drive voltage V1 output unit 171, where it is converted into the drive voltage V1 suitable for the operation of the drive circuit 156. Similarly, the output of the DC power supply unit 162 is output to the drive voltage V2 output unit 172, where it is converted into the drive voltage V2 suitable for the operation of the current sensor 157. Such drive voltage V1 output unit 171 and drive voltage V2 output unit 172 can be implemented as well-known DC / DC converters. Note that, in this embodiment, three DC power supply units 160 to 162 that output the same second voltage Vcc are prepared to ensure the current capacity required for the operation of each part. However, if the current capacity can be ensured, power may be supplied from one DC power supply unit 160. Also, each of the DC power supply units 160 to 162 may be configured to output the voltage required for the operation of the control unit 158, the drive circuit 156, and the current sensor 157, which are the power supply destinations. In this case, the drive voltage V1 output unit 171 and the drive voltage V2 output unit 172 are not necessary.

[0045] In the power transmission device 150 of this embodiment, when the power receiving coil 31 of the power receiving device 30 is not close, the impedance of the impedance circuit 55 is high, and only a small current (standby current) flows through the resonance circuit 53. This current value Ir is detected by the current sensor 157 and output to the control unit 158. In the steady state where the second voltage Vcc supplied from each DC power supply unit 160 is established, the control unit 158 monitors this current value Ir and detects the approach of the power receiving coil 31. When the power receiving coil 31 approaches the power transmission coil 51, the current flowing through the resonance circuit 53 increases due to magnetic field coupling. When the current value Ir flowing through the resonance circuit 53 exceeds a predetermined threshold, the control unit 158 outputs a drive signal via the drive circuit 156, assuming that the power receiving coil 31 has approached, and switches the impedance of the impedance circuit 55 to a low value. As a result, the current value Ir flowing through the resonance circuit 53 increases, and power is supplied to the power receiving device 30 via magnetic field coupling. Conversely, if the power receiving coil 31 moves away from the power transmission coil 51, the current value Ir decreases. Therefore, the control unit 158 compares this with a predetermined threshold, and if the current value Ir becomes equal to or less than the threshold, the impedance circuit 55 is switched to a high impedance state.

[0046] The impedance control for switching the impedance of the impedance circuit 55 by the control unit 158 and the power control for turning on and off the supply of AC power to the power transmission coil 51 described above as the first embodiment are premised on the normal operation of the control unit 158. The control unit 158 can be realized as a discrete electric circuit, but in this embodiment, it is configured as a microcomputer including a CPU that performs arithmetic and logical operations and a memory that stores a program for causing this CPU to perform a predetermined control operation. In the case of a control unit 158 that performs arithmetic and logical operations such as such a microcomputer, it is a prerequisite for ensuring normal operation that the operating second voltage Vcc is within a predetermined rated range. The second voltage Vcc generally tends to be in an unstable state for a predetermined time immediately after the power supply from the main power supply device 70 to the power transmission device 150 is started, and in some cases, the result of arithmetic and logical operations may not be guaranteed.

[0047] As described in the first embodiment, when a plurality of power transmission devices are provided, instead of supplying AC power from the main power supply device 70 to all the power transmission devices, there are cases where AC power is supplied from the main power supply device 70 only to the power transmission device 150 that may be involved in power supply. In such cases, each of the DC power supply units 160 to 162 outputs the power supply voltage Vcc only after receiving the AC power supply from the main power supply device 70. Therefore, in this embodiment, the following processing is performed in order to stably operate the control unit 158 that uses the second voltage Vcc.

[0048] The control unit 158 configured as a microcomputer executes the power-on processing shown in FIG. 17. "Power-on" refers to the timing when the second voltage Vcc applied to the power supply terminal of the control unit 158 becomes greater than the first threshold value Von, which is the voltage at which the microcomputer constituting the control unit 158 starts operating. The timing chart at power-on is shown in FIG. 18. As shown in the figure, if the timing when the main power supply device 70 is started and the supply of AC power to the main power line RFP is started is defined as time t0, the second voltage Vcc output by the DC power supply unit 160 gradually increases and eventually reaches the rated voltage Vcc. When the second voltage Vcc rises and becomes higher than the first threshold value Von at time t1, the microcomputer constituting the control unit 158 activates the arithmetic logic unit inside the control circuit (step S101). This process corresponds to the initialization process in the microcomputer.

[0049] Subsequently, a process of turning on the output mask is performed (step S111). The output mask refers to a process of masking the output signal output from the output terminal of the control unit 158 and uniformly turning it off. The output terminal with the mask turned on will have its output turned off regardless of whether the result of the arithmetic logic operation in the microcomputer is value 1 (logical high) or value 0 (logical low). Here, all the output terminals are set to have the mask turned on. As a result, all the output terminals of the control unit 158 are turned off, and the impedance circuit 55 is also maintained in the default low-impedance state.

[0050] After that, the microcomputer activates the built-in timer counter (step S121). Since the timer counter counts up the value TCC of the counter at a predetermined interval, as illustrated in FIG. 18, its value increases at a predetermined gradient. The microcomputer repeatedly determines the magnitude relationship between the value TCC of this timer counter and the threshold value Thc corresponding to a predetermined time until the counter value TCC becomes larger than the threshold value Thc (step S131). As shown as time t2 in FIG. 18, when the counter value TCC becomes larger than the threshold value Thc, the timer counter is reset to the value 0 (step S141), and a process of switching the output mask that has been turned on to off is performed (step S151). As a result, the output of the control unit 158 is masked between time t1 and time t2. After the above process, the program branches to "NEXT", this processing routine ends, and when the microcomputer of the control unit 158 determines the approach of the power receiving coil 31 of the power receiving device 30, for example, during normal control, it executes impedance control such as reducing the impedance of the impedance circuit 55 and increasing the current value Ir of the resonance circuit 53.

[0051] In this embodiment, even when the second voltage Vcc supplied to the control unit 158 exceeds the first threshold value Von at which the microcomputer constituting the control unit 158 can start its operation, the output of the control unit 158 is masked for a predetermined time. Therefore, during this period, the power transmission device 150 does not output to various control targets including the impedance circuit 55, and after the second voltage Vcc becomes stable, the control unit 158 can output to the control targets. As a result, it is possible to suppress the occurrence of malfunction due to the instability of the second voltage Vcc when the power is turned on.

[0052] In this embodiment, the output from the control unit 158 is masked for a predetermined time after the second voltage Vcc exceeds the first threshold Von. However, a time counter may be realized software-wise in the microcomputer within the control unit 158 to only monitor the elapse of a predetermined time, or instructions that are not substantial processes such as NOP may be repeatedly executed. Alternatively, a circuit that repeatedly generates an NMI to the microcomputer may be provided within the control unit 158, and an interrupt that cannot be masked may be applied for a predetermined period to cause the microcomputer to repeatedly perform processes other than normal control, such as initialization processes.

[0053] F. Sixth Embodiment: Next, the sixth embodiment will be described. The hardware configuration of the sixth embodiment is the same as that of the fifth embodiment, but the content of the power-on processing is different. In the sixth embodiment, the control unit 158 of the power transmission device 150 executes the processing shown in FIG. 19 when the power is turned on. When the main power supply device 70 is activated and the supply of AC power at the first voltage to the main power line RFP is started, the second voltage Vcc rises and becomes higher than the first threshold Von at time t1. At this timing, the microcomputer constituting the control unit 158 activates the arithmetic logic unit inside the control circuit (step S201).

[0054] Subsequently, similar to the fifth embodiment, a process of turning on the output mask is performed (step S211). As a result, all output terminals of the control unit 158 are turned off, and the impedance circuit 55 is also maintained in the low-impedance state, which is the default state. After that, the microcomputer performs a process of acquiring the drive voltage V1, which is the power supply voltage of the drive circuit 156, and the drive voltage V2, which is the power supply voltage of the current sensor 157 (step S221). It is determined whether the acquired drive voltage V1 is greater than a predetermined second threshold Va and the drive voltage V2 is greater than a predetermined third threshold Vb (step S231). The second threshold Va and the third threshold Vb used for the determination of the drive voltage V1 and the drive voltage V2 may be the same or different.

[0055] V1 > Va and V2 > Vb... (Condition 1) The process of step S231 is repeated until the condition is satisfied. When it is determined that the above condition 1 is satisfied, a process of turning off the output mask (step S241) is executed. This is shown in FIG. 20. As shown in the figure, when the second voltage Vcc, which is the power supply voltage of the control unit 158, becomes higher than the first threshold value Von, the output mask is turned on and this state is maintained until the above condition 1 is satisfied. When both the driving voltages V1 and V2 become larger than the predetermined second and third threshold values Va and Vb, respectively, the output mask is turned off and the output of the control unit 158 becomes effective for the first time. Thus, in the sixth embodiment, the timer counter of the fifth embodiment is not used, but the same operational effects as those of the fifth embodiment are achieved. Further, in the sixth embodiment, the driving voltage V1, which is the power supply voltage of the driving circuit 156, and the driving voltage V2, which is the power supply voltage of the current sensor 157, are directly detected, and after confirming that they are power supply voltages at which each circuit and sensor can operate normally, the output mask is turned off. Therefore, the unstable operation at the time of power-on can be more reliably avoided. Note that, similar to the fifth embodiment, the output of the control unit 158 may be invalidated by a method other than turning on the output mask.

[0056] G. Seventh Embodiment: The configuration of the power transmission device 250 according to the seventh embodiment is shown in FIG. 21. As shown in the figure, this power transmission device 250 operates with an alternating current voltage ACP as the first voltage applied to the two power lines NL1 and NL2. The power transmission device 250 includes a first capacitor Cs and a second capacitor Cr that form a resonance circuit 253 together with the power transmission coil 251, a switching element SW1 that switches the connection of the second capacitor Cr, and a blocking unit 255 that blocks the application of the alternating current voltage ACP to the resonance circuit 253. When the switching element SW1 is turned on (connected state), the second capacitor Cr is connected in parallel with the first capacitor Cs. This switching element SW1 performs impedance control. Further, the blocking unit 255 performs protection control.

[0057] In the resonance circuit 253, two capacitors are connected in series with respect to the power transmission coil 251 to form a series resonance (SS) circuit. In this embodiment, the frequency of the alternating current voltage ACP is 85 kHz, and the capacitances of the first capacitor Cs and the second capacitor Cr are such that when the switching element SW1 is on, that is, when the two capacitors are connected in parallel and the capacitance with respect to the inductance of the power transmission coil 251 becomes the sum of the capacitances of both capacitors, the resonance frequency of the resonance circuit 253 is set to match the frequency of the alternating current voltage ACP. On the other hand, when the switching element SW1 is in the off state, the resonance frequency of the resonance circuit 253 composed of the power transmission coil 251 and the first capacitor Cs is deviated from the frequency of the alternating current voltage applied by the alternating current voltage ACP. Since alternating current is applied to the two power lines NL1 and NL2, neither of them is the ground line GND. For the sake of convenience, in the following description, the power line NL2 may be referred to as the ground line GND.

[0058] The power transmission device 250 is provided with a gate circuit 267 that drives the switching element SW1 and the cutoff unit 255. The gate circuit 267 is connected to the output ports P1 and P2 of the control unit 265, and when the ports P1 and P2 are set to the high level, it drives the switching element SW1 and the cutoff unit 255. The cutoff unit 255 determines whether or not to apply the alternating current voltage ACP to the resonance circuit 253. The cutoff unit 255 may be electrically on / off capable, such as a relay contact, a fuse, a semiconductor switching element, etc., and may operate reversibly or irreversibly. In this embodiment, the cutoff unit 255 is configured to operate reversibly using a semiconductor switch, but it may also be configured using a component that is irreversibly turned off by an external signal. For example, it may be a thermal fuse type fuse equipped with a heater, and the heater is heated by a signal from the gate circuit 267 to melt the fuse. Alternatively, it may be configured like a breaker, such that once it is turned off, it does not return to the conductive state without manual or return processing from the control unit 265.

[0059] The power transmission device 250 is also provided with an abnormality detector 261 and a proximity sensor 263, among others. The abnormality detector 261 is for detecting an abnormality in the power transmission device 250, and may be, for example, a current sensor that detects overheating or overcurrent of the power transmission device 250. When it is a sensor for detecting overheating of the power transmission coil 251, etc., the abnormality detector 261 is provided so as to be thermally coupled to the detection target. Alternatively, it may be a device that communicates with the control unit 265 and the control circuit 43 on the power receiving device 30 side to detect an abnormality in the non-contact power supply system 100. For example, it may be a device that detects as an abnormality that the proximity sensor 263 has erroneously detected the proximity of the power receiving device 30. In such a case, the power transmission device 250 may be provided with a communication unit that communicates with the power receiving device 30.

[0060] In this power transmission device 250, the DC power of the second voltage Vcc output from the DC power supply unit 260 is supplied not only to the control unit 265 but also to the abnormality detector 261 and the proximity sensor 263. Further, a voltage condition detector 262 is connected to the power line of the second voltage Vcc to determine whether or not the second voltage Vcc is established. As the determination method, the same method as in the fifth embodiment or the sixth embodiment can be adopted.

[0061] In the seventh embodiment, until the voltage condition detector 262 determines that the second voltage Vcc is established, a signal is output to the reset terminal RST (or the operation inhibition terminal INH) of the control unit 265 to stop the operation of the control unit 265. At the same time as this, or separately from this, the voltage condition detector 262 outputs a signal to the operation inhibition terminal INH of the gate circuit 267 to prohibit the output of the gate circuit 267 or set it to a high impedance state.

[0062] In the power transmission device 250 of the seventh embodiment described above, when the power is turned on, no signal is output to the cutoff unit 255 or the switching element SW1 until the second voltage Vcc or the like of the DC power supply supplied to the control unit 265 or the like is established. For this reason, it is possible to suppress the occurrence of a situation in which the control unit 265 outputs an incorrect signal to the cutoff unit 255 or the switching element SW1 due to the unstable power supply voltage of the control unit 265 itself, the abnormality detector 261, the proximity sensor 263, etc., and induces malfunction in the protection control or the impedance control.

[0063] H. Other Configuration Examples of DC Power Supply and Second Power Supply: As described above, various embodiments and configuration examples have been described. However, the DC power supply units 60, 160, 260 and the second power supply units 42, 42A - 42D are not limited to positive voltages, and may be configured to generate negative voltages and supply power of the negative voltages to necessary circuits. For example, as shown in FIG. 22, it is easy to output negative voltages with circuit configurations corresponding to Configuration Example 1 shown in FIG. 6, Configuration Example 2 shown in FIG. 7, and Configuration Example 3 shown in FIG. 8, respectively. In each circuit configuration of FIG. 22, the GND potential of the two lines outputting the DC voltage DCP is floating. Also, in the circuit configuration in the lower column of the same figure, the GND potential of the two lines outputting the DC voltage DCP is common to either the P or N line of the AC voltage ACP.

[0064] If necessary, the DC power supply units 60, 160, 260 and the second power supply units 42, 42A - 42D may be configured to output positive and negative voltages simultaneously. The upper and lower columns of FIG. 23 illustrate such circuit configurations. The upper column of FIG. 23 is a combination of the circuit configuration for outputting the positive voltage shown in FIG. 8 and the circuit configuration for outputting the negative voltage shown in the lower column of FIG. 22. In this circuit configuration, the GND of the DC voltage DCP is common to either the P or N line of the AC voltage ACP.

[0065] The lower column of FIG. 23 shows another circuit configuration example that outputs both positive and negative voltages. This example is a combination of the circuit configuration for outputting a positive voltage shown in FIG. 7 and the circuit configuration for outputting a negative voltage shown in the middle column of FIG. 22. In this circuit configuration, the GND potential of the DC voltage DCP is floating. In this circuit configuration, both positive and negative voltages can be output simultaneously, and the capacitor CC2 can be used concurrently, so that the number of circuit configuration components can be reduced.

[0066] I. Other Embodiments: (1) One of the other embodiments is in the form of a non-contact power transmission system. This non-contact power transmission system is provided within the movable range of a moving body and includes a plurality of power transmission devices each having a power transmission coil for non-contact power transmission to the power receiving device of the moving body, a main power supply line for supplying AC power of a first voltage used for the power transmission to the plurality of power transmission devices, and a DC power supply unit that receives the supply of AC power from the main power supply line and outputs power of a second voltage that is lower than the first voltage and is used for control within the power transmission device. According to this non-contact power transmission system, there is no need to lay a line for a second voltage that is lower than the first voltage in addition to the main power supply line for supplying AC power of the first voltage, and the configuration of the power transmission system can be simplified.

[0067] A plurality of power transmission devices may be arranged along the moving path of the moving body, or may be arranged to cover a two-dimensional plane. The moving body that receives power supply via the power receiving device may be a four-wheeled automobile, a two-wheeled vehicle, a large bus or truck, etc., or may be an unmanned vehicle such as an automated guided vehicle. Of course, it may also be a moving body that moves without using wheels, such as a hovercraft or a magnetic levitation linear motor car. The power transmission coil that transmits alternating current non-contact using magnetic coupling may be housed inside the housing of the power transmission device, or may be exposed to the outside. The power transmission coil may be disposed or embedded on the floor or road surface where the moving body moves, or may be disposed on a wall or ceiling, etc. When the moving body is a straddle-type monorail or the like, power supply and reception by magnetic coupling may be performed within the rail that restricts the movement of the moving body. The power transmission coil may be arranged to face the power receiving coil closely, or a relay coil may be sandwiched between the power transmission coil and the power receiving coil so as to be powered. In this case, when the moving body is equipped with wheels such as tires, a configuration in which the relay coil is provided inside the tire or its wheel can also be adopted. In the above embodiment, the plurality of power transmission devices 50 have been described as performing a power supply operation by switching according to the approach of the moving body 20, but they may always perform a power supply operation.

[0068] In each of the above embodiments, the control circuit 58 has been described as detecting the position and approach of the moving body 20 using the Hall element 57. However, as a circuit that operates upon receiving the DC voltage from the DC power supply unit 260, other circuit configurations may be used. For example, instead of the Hall element 57, a circuit that detects the position and approach of the moving body 20 using a detection coil, a circuit that detects from the current flowing through the power transmission coil 51 or the voltage across both ends of the power transmission coil 51, a circuit that detects from the current or voltage of the resonance capacitor 52, etc. may also be used. Further, the object controlled by the control circuit 58 is not limited to the impedance circuit 55, and any circuit that is necessary for each power transmission device 50 and utilizes a DC voltage may be used. For example, if it is a circuit that varies the resonance frequency of the resonance circuit, a circuit configuration using a variable capacitor, a series-parallel switching circuit of a capacitor using a capacitor and a switching element, a winding number switching circuit of a coil using a switching element, etc. may also be adopted. In the above embodiment, a circuit configuration for turning on and off the supply of high-frequency power is used. Such a circuit can be configured using a relay, a switching element, etc.

[0069] (2) In such a configuration, the plurality of power transmission devices may be connected in parallel to the main power line, and the DC power supply unit may be provided corresponding to the power transmission devices or within the power transmission devices, respectively. By doing so, the degree of freedom in arranging the plurality of power transmission devices can be increased. The DC power supply unit may be provided within the power transmission device, or may be provided in proximity to the outside corresponding to the power transmission device. Also, one DC power supply unit may be provided corresponding to the plurality of power transmission devices. In this case, wiring from the DC power supply unit to the power transmission device is required, but the wiring distance and installation man-hours can be reduced compared to laying a power line that supplies power of the second voltage to all the power transmission devices.

[0070] (3) In the configurations (1) and (2) described above, the connection between the DC power supply line, which is the power supply line of the DC power supply unit, and the main power supply line may be made via a capacitor for insulation. By doing so, even if the AC voltage of the main power supply line is dissociated from the second voltage output by the DC power supply unit, it is possible to obtain the DC voltage output by the second power supply unit without using large components such as a step-down transformer. Also, if a capacitor for insulation is installed in all connections to the main power supply line, the DC power supply unit can be easily insulated from the main power supply line, and noise resistance performance and the like can be improved.

[0071] (4) In the configurations (1) to (3) described above, the main power supply line is a single-phase AC line, and the capacitor for insulation may be provided on at least one side of the power supply line of the DC power supply unit. By doing so, conversion from a single-phase AC line to DC can be realized with a simple configuration.

[0072] (5) In the configurations (1) to (4) described above, the DC power supply unit may include, in order from the upstream side of power supply, a rectifying unit using a diode and a stabilized power supply unit including a Zener diode and a smoothing capacitor connected in parallel to the DC power supply line. By doing so, a stable DC voltage can be obtained with a simple configuration. The stabilized power supply unit is not limited to a configuration using a Zener diode, and a circuit configuration using a transistor or a three-terminal regulator adjusted to a predetermined voltage output may also be used.

[0073] (6) In the configurations (1) to (5) described above, the rectifying unit may be configured as a half-wave rectifier or a full-wave rectifier. By doing so, if the power is sufficient, the number of diodes for rectification can be reduced, contributing to resource savings.

[0074] (7) In the configurations (1) to (6) described above, the rectifying unit may include a diode installed on one side of the DC power supply line and a backflow prevention diode installed on the other side of the power supply line. By doing so, backflow can be prevented.

[0075] (8) In the configuration of (1) to (7) described above, as the control in the power transmission device, specifically, the control performed by the control circuit 58 shown in FIG. 1, [1] Power control for turning on and off the supply of AC power of the first voltage to the power transmission coil, [2] Impedance control for varying the resonance state of the resonance circuit using the power transmission coil, [3] Detection control for detecting the power reception coil on the moving body side, [4] Drive control for the switching element existing in the power transmission device, [5] Protection control for operating the protection circuit provided in the power transmission device, may include at least one of these. By doing so, by providing a DC power supply unit, various controls can be supported. As the control for varying the resonance state of the resonance circuit, there can be various controls such as control for changing the resonance frequency and control for changing the sharpness of resonance (Q value).

[0076] (9) In such a configuration, further, a control unit that operates based on the second voltage output from the DC power supply unit and performs the control is provided. When the DC power supply unit receives the supply of AC power from the main power line and starts to output the second voltage, until a predetermined operating condition is satisfied, the control unit may suspend the execution of at least a part of the control. The suspension of the execution of at least a part of the control includes not performing any control until the operating condition is satisfied, not performing at least the control related to power transmission, not performing at least the control related to safety, or performing the control on the safest side even when performing the control. Performing the control on the safest side means, for example, in the case of impedance control, controlling the resonance state of the resonance circuit to a side lower than the peak. If the control unit adopts a configuration in which an arithmetic and logic operation circuit such as a microcomputer is operated by a program, various measures such as stopping the execution of the program and prohibiting or suppressing the output of the execution result are possible. When the control unit adopts a discrete circuit configuration that performs sequential control such as a ladder or a PLC, for the time until the second voltage is established, a part of the sequence may be stopped.

[0077] (10) In such a configuration, the operating condition is 〈1〉 that a predetermined period has elapsed after the second voltage becomes equal to or higher than a first threshold value predetermined as a voltage at which the control unit can operate, 〈2〉 when the control unit performs at least one of the power control and the impedance control, the first voltage condition that the second voltage becomes equal to or higher than a first threshold value predetermined as a voltage at which the control unit can operate, and the second voltage becomes equal to or higher than a second threshold value predetermined as a voltage at which the sensors required for the power control and the impedance control can operate, or the second voltage condition that a predetermined period has elapsed after the second voltage becomes equal to or higher than the first threshold value and the second threshold value are both satisfied. (3) When the control unit performs at least one of the detection control and the protection control, the second voltage becomes equal to or higher than a first threshold value predetermined as a voltage at which the control unit can operate, and becomes equal to or higher than a third threshold value predetermined as a voltage at which a detection unit necessary for the detection control and the protection control can operate, or a predetermined period has elapsed after the second voltage becomes equal to or higher than the first threshold value and the third threshold value. It may include any one of them. In this way, the certainty of each control can be enhanced. As other operating conditions, receiving a permission signal from a diagnosis device that is provided for the entire non-contact power supply system and communicates with each of a plurality of power transmission devices, or a configuration in which the power transmission devices communicate with each other, confirm each other's operating conditions, and permit each other may be adopted.

[0078] (11) In such item 2, the control unit includes an arithmetic logic unit that performs the control by executing a program, and the suspension of the execution of at least a part of the control (A) stopping the execution of the arithmetic logic unit (B) prohibiting the output based on the operation result of the arithmetic logic unit (C) a gate circuit that inputs the output signal of the arithmetic logic unit and does not output it until a permission signal is input It may be realized by any one of them.

[0079] (12) One of the other embodiments is in the form of a non-contact power supply system. This non-contact power supply system includes a power receiving device having a power receiving coil provided inside a moving body, and a plurality of power transmitting devices provided within the movable range of the moving body, magnetically coupled to the power receiving coil of the power receiving device of the moving body to transmit power non-contact, and a main power supply line for supplying AC power of a first voltage used for the power transmission to the plurality of power transmitting devices, and a DC power supply unit that receives supply of AC power from the main power supply line and outputs power of a second voltage that is lower than the first voltage and is used for control within the power transmitting device. In this way, non-contact power supply can be performed for the power receiving device, and the supply of the second voltage for control on the power transmitting device side can be simplified. As a result, the configuration of the non-contact power supply system can be made simple, and the man-hours for laying on the power transmitting side and the like can be reduced.

[0080] (13) In such a configuration, the plurality of power transmitting devices may be connected in parallel to the main power supply line, and the DC power supply unit may be provided corresponding to the power transmitting devices or within the power transmitting devices, respectively. In this way, the degree of freedom in arranging the plurality of power transmitting devices can be increased. The DC power supply unit may be provided within the power transmitting device, or may be provided in proximity to the outside thereof corresponding to the power transmitting device. Also, one DC power supply unit may be provided corresponding to the plurality of power transmitting devices.

[0081] (14) One of the other embodiments is in the form of a contactless power supply method. In this contactless power supply method, a plurality of power transmission devices provided within the movable range of a moving body are supplied with AC power of a first voltage via a main power line, and a DC power supply unit that receives the supply of AC power from the main power line outputs power of a second voltage that is lower than the first voltage and is the operating voltage of a control unit within the power transmission device. With the control of the control unit, at least one of the plurality of power transmission devices supplies high-frequency AC power to a power transmission coil provided in the power transmission device using the AC power of the first voltage, and power is transmitted non-contactingly to a power reception coil of a power reception device of the moving body via the power transmission coil. By doing so, there is no need to lay a line for the second voltage, which is lower than the first voltage, in addition to the main power line that supplies AC power of the first voltage, and the configuration of the contactless power supply system can be simplified.

[0082] (15) In each of the above embodiments, a part of the configuration that was realized by hardware may be replaced with software. At least a part of the configuration that was realized by software can also be realized by a discrete circuit configuration. Further, when a part or all of the functions of the present disclosure are realized by software, the software (computer program) can be provided in a form stored in a computer-readable recording medium. The "computer-readable recording medium" includes not only portable recording media such as flexible disks and CD-ROMs, but also various internal storage devices within a computer such as various RAMs and ROMs, and external storage devices fixed to a computer such as hard disks. That is, the "computer-readable recording medium" has a broad meaning including any recording medium capable of fixedly storing data packets not temporarily.

[0083] The present disclosure is not limited to the above-described embodiments, and can be implemented in various configurations without departing from the gist thereof. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary of the invention can be appropriately replaced or combined in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Further, if the technical feature is not described as essential in this specification, it can be appropriately deleted.

[0084] The present disclosure is not limited to the above-described embodiments, and can be implemented in various configurations without departing from the gist thereof. For example, the technical features of the embodiments corresponding to the technical features in each form described in the summary of the invention can be appropriately replaced or combined in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Further, if the technical feature is not described as essential in this specification, it can be appropriately deleted. For example, a part of the configuration realized by hardware in the above embodiment can be realized by software.

Description of Reference Numerals

[0085] 20…Moving body, 21…Drive wheel, 22…Driven wheel, 24…Magnet, 30, 30A - 30E…Power receiving device, 31…Power receiving coil, 33, 33A…Power receiving side resonance circuit, 34…Rectifier circuit, 35, 35A…Impedance filter, 36…Lower arm, 37…Short - circuit contact, 39…Smoothing capacitor, 41…First power supply unit, 42, 42A - 42D…Second power supply unit, 43…Control circuit, 44…Drive control circuit, 44A…Cut - off control circuit, 44B…Cut - off control circuit, 44C…Cut - off control circuit, 45…Load device, 46…Inverter, 47…Battery, 48…Moving motor, 49…Control circuit, 50, 150, 250…Power transmission device, 51, 251…Power transmission coil, 52…Resonance capacitor, 53, 253…Resonance circuit, 55, 255…Impedance circuit, 57…Hall element, 58…Control circuit, 60, 60A - 60D, 160 - 162, 260…DC power supply unit, 70…Main power supply device, 71…Filter, 72…PFC circuit, 73…Inverter, 74…Filter, 80…Main power supply, 100…Contactless power supply system, 156…Drive circuit, 157…Current sensor, 158, 265…Control unit, 171…Drive voltage V1 output unit, 172…Drive voltage V2 output unit, 200…Power transmission system, 261…Abnormality detector, 263…Proximity sensor, 267…Gate circuit

Claims

1. A plurality of power transmission devices (50) provided in the movable range of a moving body (20) and including a power transmission coil (51) for non-contact power transmission to a power receiving device (30) of the moving body; A main power line (RFP) for supplying AC power of a first voltage used for the power transmission to the plurality of power transmission devices; A DC power supply unit (60) that receives supply of AC power from the main power line, outputs power of a second voltage that is lower than the first voltage and is used for control within the power transmission device; A non-contact power transmission system (200) including the above.

2. The plurality of power transmission devices are connected in parallel to the main power line; The DC power supply unit is provided corresponding to or within each of the power transmission devices, and the non-contact power transmission system according to Claim 1.

3. The connection between the DC power supply lines (LN1, LN2) that are the power lines of the DC power supply unit and the main power line is performed via insulation capacitors (CC1, CC2), and the non-contact power transmission system according to Claim 1.

4. The main power line is a single-phase AC line, and the insulation capacitor is provided on at least one side of the power line of the DC power supply unit, and the non-contact power transmission system according to Claim 3.

5. The DC power supply unit includes, in order from the upstream side of power supply, a rectifying unit (RE) using a diode (RD1), and a stabilizing power supply unit (SP) including a Zener diode (TzD) and a smoothing capacitor (CF) connected in parallel to the DC power supply line; The non-contact power transmission system according to Claim 3.

6. The rectifying unit is configured as a half-wave rectifier or a full-wave rectifier, and the non-contact power transmission system according to Claim 5.

7. The rectifying unit includes a rectifying diode (PD1) interposed on one side of the DC power supply line and a reverse blocking diode (PD2) interposed on the other side of the power line, and the non-contact power transmission system according to Claim 5.

8. The control within the power transmission device includes: [1] Power control for turning on and off the supply of AC power of the first voltage to the power transmission coil; [2] Impedance control for varying the resonance state of a resonance circuit using the power transmission coil; [3] Detection control for detecting a power receiving coil (31) on the moving body side; [4] Drive control for a switching element (SW1) existing within the power transmission device; [5] Protection control for operating a protection circuit (255) provided within the power transmission device. The non-contact power transmission system according to any one of claims 1 to 7, including at least one of them.

9. A control unit (158, 265) that operates by the second voltage output from the DC power supply unit and performs the control is provided. When the DC power supply unit receives the supply of AC power from the main power line and starts to output the second voltage, until a predetermined operating condition is satisfied, the control unit suspends the execution of at least a part of the control. The non-contact power transmission system according to claim 8.

10. The operating conditions are 〈1〉That a predetermined period has elapsed after the second voltage becomes equal to or higher than a first threshold value predetermined as a voltage at which the control unit can operate. 〈2〉When the control unit performs at least one of the power control and the impedance control, the second voltage satisfies a first voltage condition of becoming equal to or higher than a first threshold value predetermined as a voltage at which the control unit can operate, and becomes equal to or higher than a second threshold value predetermined as a voltage at which a sensor (157) necessary for the power control and the impedance control can operate, or a second voltage condition that a predetermined period has elapsed after the second voltage becomes equal to or higher than the first threshold value and the second threshold value is satisfied. 〈3〉When the control unit performs at least one of the detection control and the protection control, the second voltage becomes equal to or higher than a first threshold value predetermined as a voltage at which the control unit can operate, and a detection unit (222, 261) necessary for the detection control and the protection control becomes equal to or higher than a third threshold value predetermined as a voltage at which it can operate, or a predetermined period has elapsed after the second voltage becomes equal to or higher than the first threshold value and the third threshold value. The non-contact power transmission system according to claim 9, including any one of them.

11. The control unit includes an arithmetic logic operation circuit that performs the control by executing a program, and the suspension of the execution of at least a part of the control is (A)Stopping the execution of the arithmetic logic operation circuit (B)Prohibiting the output based on the operation result of the arithmetic logic operation circuit (C)A gate circuit (267) that inputs the output signal of the arithmetic logic operation circuit and does not output it until a permission signal is input. The non-contact power transmission system according to claim 9, realized by any one of them.

12. A power receiving device including a power receiving coil provided inside a moving body A plurality of power transmission devices provided within the movable range of the moving body, each including a power transmission coil that magnetically couples with the power reception coil of the power reception device of the moving body to perform non-contact power transmission; A main power supply line that supplies AC power of a first voltage used for the power transmission to the plurality of power transmission devices; A DC power supply unit that receives supply of AC power from the main power supply line and outputs power of a second voltage that is lower than the first voltage and is used for control within the power transmission device; A non-contact power supply system (100) including the above.

13. The plurality of power transmission devices are connected in parallel to the main power supply line; The DC power supply unit is provided corresponding to each of the power transmission devices or within each of the power transmission devices, respectively, for the non-contact power supply system according to Claim 12.

14. Supply AC power of a first voltage to a plurality of power transmission devices provided within the movable range of the moving body via a main power supply line; Output power of a second voltage that is lower than the first voltage and is the operating voltage of a control unit (58) within the power transmission device by a DC power supply unit that receives supply of AC power from the main power supply line; With the control of the control unit, at least one of the plurality of power transmission devices supplies high-frequency AC power to a power transmission coil provided in the power transmission device using the AC power of the first voltage; Perform non-contact power transmission to a power reception coil of a power reception device of the moving body via the power transmission coil; A non-contact power supply method.

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