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

Abstract

To stably secure a power source for control in a circuit configuration in a case where a load device receives electric power.SOLUTION: AC electric power received by a power-receiving coil 31, which receives electric power from the outside in a non-contact manner using magnetic field coupling, is rectified, converted into DC electric power and supplied as main electric power, which is used by a load device 45, by a first power source section 41. A second power source section 42 is connected to a pre-stage of the first power source section and outputs electric power, which is used for controlling the first power source section, as DC electric power.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a technique for non-contact power supply and reception.

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 road 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. On the moving body side that receives power supply non-contact, in addition to the main circuit for supplying power to the motive power, a control power supply for supplying a stabilized power supply to a control circuit, a protection circuit, etc. may be prepared. It is required that these control power supplies supply power to the control circuit and the protection circuit stably or at the minimum necessary level in various situations that may occur in non-contact power supply. In the case of a circuit such as a protection circuit that is expected to perform an operation to ensure file safety when a failure or the like occurs, ensuring power supply is extremely important.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a non-contact power supply system, the power receiving side often has a circuit configuration that cuts off power supply to ensure safety between a power receiving unit such as a power receiving coil that receives power non-contact and a power supply circuit. For example, when the power receiving side that receives power non-contact is equipped with a power storage device such as a battery, and adopts a configuration in which power is once stored in the battery by non-contact power supply and then power is supplied to the entire device, the non-contact power supply aims to charge the battery and is often configured as a constant current circuit. In this case, when the load side such as the battery is open and the impedance becomes high, an overvoltage will occur. There was a problem of how to secure a power supply for performing such control in order to introduce control to avoid such problems. Such a problem was the same not only for moving bodies but also for power receiving devices that supply the main power of the load device.

Means for Solving the Problems

[0005] (1) A first aspect of the present disclosure is an aspect as a power receiving device (30) that receives power supply non-contact. This power receiving device includes a power receiving coil (31) that receives AC power non-contact from the outside using magnetic field coupling, and a rectifying circuit (34) that rectifies the AC power received by the power receiving coil and converts it into DC, and a first power supply unit (41) that supplies the main power used in the load device, and a second power supply unit (42) that is connected to the front stage of the first power supply unit and outputs power for controlling the first power supply unit in DC.

[0006] (2) Another aspect of the present disclosure is an aspect as a non-contact power supply system including such a power receiving device and a power transmission device (50) including a power transmission coil (51) that magnetically couples with the power receiving coil when the power receiving coil of the power receiving device approaches and supplies the AC power to the power receiving coil.

[0007] (3) Furthermore, another aspect of the present disclosure is an aspect as a non-contact power supply method. In this non-contact power supply method, an alternating voltage is applied to a power transmission coil provided in a power transmission device, and an alternating current induced electromagnetically in a power reception coil at a position where magnetic field coupling is possible with the power transmission coil is rectified by a rectifier circuit and converted into direct current, which is used for the operation of a load device as the main power of the load device. A power supply is received from a stage before the rectifier circuit, and a power smaller than the main power is output as direct current for controlling the main power.

[0008] According to these aspects, in any case, a power supply is received from a stage before the rectifier circuit that supplies the main power of the load device, and a power smaller than the main power can be obtained as direct current, and this can be used for controlling the main power. Therefore, even when a problem occurs in a circuit that uses the main power or the supply operation of the main power stops due to a problem on the supply side of the main power, control regarding the output of the main power can be continued. Note that the present disclosure can be realized in various forms, and for example, it can be implemented in various aspects such as, in addition to a power supply device, a design method of a power reception system.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Embodiments for Carrying Out the Invention

[0010] A. First Embodiment: (A1) Overall Configuration of the Contactless Power Supply System: The schematic configuration of the non-contact power supply system 100 including the power receiving device 30 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 receiving device 30 built into the 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 receiving coil 31 disposed under the floor of the moving body 20, and a magnet 24 also disposed under the floor. The power receiving coil 31 is magnetically coupled to the power transmission coil 51 of the power transmission device 50 prepared on the road surface RS side to receive AC power supply, and this is converted to DC by the first power supply unit 41 and the second power supply unit 42 provided in the power receiving 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 in the moving body 20. The second power supply unit 42 outputs DC power used for controlling the first power supply unit 41. In addition to being buried under the road surface RS, the power transmission device 50 can be installed on the road surface or on a wall surface or ceiling. In such a case, the power receiving 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 receiving device 30 may be arranged on the side surface of the moving body 20. Also, in accordance with the laying position of the power transmission device 50, the power receiving device 30 may be moved inside the moving body 20, or a plurality of power receiving devices 30 may 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 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 this embodiment, it is assumed that each power transmission device 50 has the same configuration. However, for example, as long as power transmission is possible, such as arranging power transmission coils 51 with different sizes alternately, the configurations do not have to be the same.

[0012] 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.

[0013] 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, a switching element, or the like 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, but 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 (interrupted). For detecting the approach and departure of the moving body 20, other methods, for example, a configuration in which a change in mutual inductance due to the approach of the power reception coil 31 to the power transmission coil 51 is detected 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.

[0014] 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 the power reception side resonance circuit 33 provided in the first power supply unit 41. A rectifier circuit 34 is provided at the subsequent stage of the power reception side resonance circuit 33, and the power received by the power reception coil 31 is converted into 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.

[0015] 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 before 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.

[0016] 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 through the resonance circuit 53 composed of the resonance capacitor 52 and the power transmission coil 51, and the necessary direct current power in the power transmission device 50 is provided by the direct current power supply unit 60.

[0017] 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.

[0018] (A2) Configuration and function of the DC power supply unit and the second power supply unit: The specific configuration and function 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 its operating voltage to the control circuit 58 included in the power transmission device 50, for example, 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 provided by a DC low voltage power supply. The DC power supply unit 60 supplies this DC low voltage (here, 5V). The DC power supply unit 60 receives power supply from the main power line RFP. However, since the main power line RFP is 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 that are likely to be large-sized such as transformers are not adopted, and the circuit configuration described later with reference to FIG. 6 and below is adopted.

[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. Also in the power receiving device 30, 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. The circuit configuration 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 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. Note that 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.

[0020] 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 on / off control of the switching elements SW of the rectifier circuit 34 configured as the above-described rectifier. Note that 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, as shown in Fig. 5B. The drive control circuit 44 shown in Figs. 5A and 5B is a specific example of the control circuit 43 shown in Fig. 3.

[0021] [1] First Configuration Example of Circuit: Regarding the configurations of the DC power supply unit 60 of the above-described power transmission device 50 and the second power supply unit 42 of the power reception device 30, 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.

[0022] 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 backstop 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 called a rectifying section RE, and a circuit including the Zener diode TzD and the smoothing capacitor CF is sometimes called a stabilized power supply section SP. The rectifying section RE may include the protection diode PD1 and the backstop diode PD2. Although not particularly shown, this is the same in FIGS. 7 to 9.

[0023] 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 via the rectifying diode RD1. However, the portion 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 via 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 that the smoothing capacitor CF is not affected at all. 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, 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. Therefore, 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.

[0024] Moreover, the insulating capacitors CC1 and CC2 enable easy separation of the DC power supply units 60A and the second power supply unit 42A from the side supplying the AC voltage ACP, that is, from the main power line RFP and the power supply lines of the first power supply unit 41, and can make them less susceptible to the influence of 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 resistors are not used in the circuit configuration, there is no loss due to resistance, and the efficiency of the circuit can be increased.

[0025] [2] Second Configuration Example of 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.

[0026] [3] Third Configuration Example of 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 supply line LN2 can be used as the ground potential of the DC low voltage DCP.

[0027] [4] Fourth Configuration Example of 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.

[0028] 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 achieving high efficiency due to no loss, are the same as those of the first to third configuration examples.

[0029] 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, there is no need to use a transformer or the like for step-down and insulation of the power line, 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.

[0030] 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, there is no need to use a transformer or the like for step-down and insulation of the power line, 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.

[0031] B. Second Embodiment: Next, the power receiving device 30A 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 the 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 that outputs a voltage source, and by providing the impedance filter 35 at the output of the power receiving side resonance circuit 33A, it outputs a current source. Generally, when charging a battery, a current source output is used. The impedance filter 35 of this embodiment is composed 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.

[0032] In the second embodiment, compared with the first embodiment, the differences are that 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 instead of from the connection point between the power receiving coil 31 and the power receiving side resonance circuit 33. Even with the configuration of this 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.

[0033] The power supply location to the second power supply unit 42 is not limited to the location shown in FIG. 10, that is, the connection location between the power receiving resonance circuit 33 and the impedance filter 35. For example, as shown in FIG. 11 for the power receiving device 30B, it may be both ends of the capacitor CI in the impedance filter 35. Also, in the power receiving device, the impedance filter may be configured not to include reactors L1 and L2 inside, as shown in FIG. 12 for the power receiving device 30C. In the illustrated impedance filter 35A, the reactors L1 and L2 are not included inside, and the leakage inductance of the power receiving coil 31 connected via the power receiving 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.

[0034] C. Third Embodiment: Next, the power receiving device 30D 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 the 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.

[0035] 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 its load, the load device 45, a cutoff signal is output from the cutoff control circuit 44A to the two switching elements SL1 and SL2 of the lower arm 36, and the switching elements SL1 and SL2 are both driven 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.

[0036] In this state, power supply by the first power supply unit 41 is not performed, but since the second power supply unit 42 is receiving 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, when 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 where it does not output power. On the other hand, 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 through 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.

[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 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.

[0038] 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.

[0039] D. Fourth Embodiment: Next, the power receiving device 30E as the 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.

[0040] 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 serves as 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.

[0041] 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 operation 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, the power supplied by the second power supply unit 42 only needs to be small, 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.

[0042] E. Other Embodiments: (1) One of the other embodiments is in the form of a power receiving device that receives power supply wirelessly. This power receiving device includes a power receiving coil that wirelessly receives AC power from the outside using magnetic field coupling, a rectifier circuit that rectifies the AC power received by the power receiving coil and converts it into DC power, a first power supply unit that supplies the main power used in the 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 DC power for controlling the first power supply unit. By doing so, since the power of the second power supply unit is obtained from the front stage of the first power supply unit, even if a problem occurs in the first power supply unit or the power supply operation of the first power supply unit is stopped due to a problem on the load device side 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, and is used, for example, to generate power for moving the load device. Alternatively, it is used as power for driving auxiliary devices such as an air conditioner or a power generation device mounted on the load device. On the other hand, the power supplied by the second power supply unit is at least the power used for controlling the first power supply unit. Examples of the control of the first power supply unit may include stopping the output of the first power supply unit, cutting off the output of the first power supply unit, or operating a protection circuit that protects the first power supply unit. The power supplied by the second power supply unit is used to realize these operations. Of course, the power of the second power supply unit may supply power to other control circuits or the like. For example, it may be used as power for emergency communication that communicates with the outside in an emergency, power for driving an emergency alarm sound generator or a warning light, power for a backup power supply circuit for a drive recorder or a memory mounted on the load device, and the like.

[0044] Examples of the load device may include various devices such as a power device such as a motor or a solenoid, a heating element such as a heater, a light emitting element such as a light, and a sound emitting element such as a speaker.

[0045] (2) In such a configuration, the load device may be a device provided on a moving body. The moving body on which the load device is provided 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 receiving coil that receives an alternating current non-contact from the outside using magnetic coupling may be housed inside the housing of the moving body, or may be exposed to the outside. The power transmitting coil that supplies power to the power receiving coil by magnetic coupling may be disposed or buried on the floor or road surface on which the moving body moves, or may be disposed on a wall or ceiling, etc. When the moving body is like a straddle-type monorail, power reception and supply by magnetic coupling may be performed within the rail that restricts the movement of the moving body. The power receiving coil may be arranged so as to be close to and face the power transmitting coil, or a relay coil may be sandwiched between the power receiving coil and the power transmitting 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. As the load device of the moving body, for example, various devices such as a motor for moving the moving body, a cell motor, a heater or a compressor for air conditioning, various pumps, and electrical components may be applicable.

[0046] (3) In such a configuration, the filter unit may be an impedance filter composed of a reactor and a capacitor. By doing so, when the power receiving coil and the resonance circuit function as a voltage source output, an impedance filter can be connected to this to obtain a current source output. As the impedance filter, various configurations can be adopted, not limited to the T-LCL type, such as the π type.

[0047] (4) In such a configuration, the input side of the second power supply unit may be connected to the input side of the impedance filter or in parallel with the capacitor constituting the impedance filter. In this way, even if a problem occurs in the subsequent 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 impedance filter and continue to supply power, and can control the first power supply unit using that power. The input side of the second power supply unit may be connected to both ends of the power receiving coil, or may be connected to the output side of the resonance circuit when the power receiving coil is connected to the resonance circuit.

[0048] (5) In the configuration of (3) or (4) described above, a short - circuit circuit may be provided in the stage before the rectifier circuit of the first power supply unit, which is controlled by the power output in direct current from the second power supply unit to cut off the power supply to the rectifier circuit. In this way, the power supply from the first power supply unit can be cut off. Also, if an appropriate filter unit such as an impedance filter is provided in the stage before the rectifier circuit, the power supply to the second power supply unit can be continued even when cutting off the power supply using the short - circuit circuit. The short - circuit circuit may be realized using a switching element or by a relay contact or the like.

[0049] (6) In the configuration of (3) or (4) described above, the rectifier circuit of the first power supply unit is a synchronous rectifier equipped with a switching element, and short - circuit control may be performed to simultaneously turn on the switching elements provided on one power line of the synchronous rectifier. In this way, short - circuit control can be realized using a part of the rectifier circuit, the circuit configuration can be made smaller, and resources can be saved.

[0050] (7) In such a configuration, the second power supply unit may supply sufficient power for implementing the short - circuit control. In this way, there will be no power shortage in the short - circuit control.

[0051] (8) In such a configuration, an insulating capacitor is interposed in at least one of the power lines connecting the power receiving coil and the second power supply unit. The second power supply unit may include, from upstream, a rectifying unit using a diode and a stabilizing power supply unit including a Zener diode and a smoothing capacitor connected in parallel to the power line. In this way, even if the AC voltage received by the power receiving coil is dissociated 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. Also, if insulating capacitors are interposed in all of the power lines, the second power supply unit can be insulated from the circuit from the power receiving coil to the first power supply unit, and noise resistance performance and the like can be improved. The stabilizing 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.

[0052] (9) In such a configuration, the rectifying unit may be configured as a half-wave rectifier or a full-wave rectifier. In this way, an appropriate configuration can be adopted according to the required power. If the power obtained by half-wave rectification is sufficient, the number of rectifying diodes can be reduced, contributing to resource savings.

[0053] (10) In such a configuration, the rectifying unit may include a diode interposed in one of the power lines and a reverse blocking diode interposed in the other of the power lines. In this way, reverse current can be prevented.

[0054] (11) One of the other embodiments of the present disclosure is an aspect as a non-contact power supply system. This non-contact power supply system includes the power receiving device according to any one of (1) to (10) above and a power transmission device including a power transmission coil that magnetically couples with the power receiving coil and supplies the AC power to the power receiving coil when the power receiving coil of the power receiving device approaches. In this way, a non-contact power supply system can be easily realized.

[0055] (12) In such a configuration, the power transmission device includes a power transmission side resonance circuit composed of the power transmission coil and the power transmission capacitor, and the power reception device includes a power reception side resonance circuit composed of the power reception coil and the power reception capacitor. The AC power is received via the power reception 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 reception side resonance circuit. In this way, high-efficiency non-contact power supply can be realized by utilizing resonance. Of course, the frequency of the alternating current for power supply and reception does not have to exactly match the resonance frequency which is the peak of resonance in the resonance circuit. As long as it is within the range allowed in the system design, power transmission and reception may be performed at a frequency deviated from the resonance frequency. Also, it is not limited to a configuration where one power reception device on the load device side receives power only from one power transmission device, and a configuration where power is simultaneously supplied from a plurality of power transmission devices can also be adopted. The plurality of power transmission devices 50 were described in the above embodiment as switching and performing a power supply operation in response to the approach of the moving body 20, but they may always perform a power supply operation.

[0056] (13) Another aspect of the present disclosure is an aspect as a non-contact power supply method. This non-contact power supply method applies an AC voltage to a power transmission coil provided in a power transmission device, rectifies the alternating current electromagnetically induced in a power reception coil at a position where magnetic field coupling is possible with the power transmission coil by a rectifier circuit and converts it into direct current, and uses it for the load device on the power reception side as the main power for use by the load device. In order to receive power supply from a stage before the rectifier circuit and control the main power, a power smaller than the main power may be output in direct current. In this way, since the latter obtains power from a stage before the rectifier circuit, even if a problem occurs in a circuit that uses the main power or the power supply operation of the main power stops due to a problem on the side supplying the main power, control regarding the output of the main power can be continued.

[0057] (14) In each of the above-described embodiments, a part of the configuration realized by hardware may be replaced with software. At least a part of the configuration 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 in 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.

[0058] The present disclosure is not limited to the above-described embodiments, and can be realized 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.

[0059] The present disclosure is not limited to the above-described embodiments, and can be realized 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 Symbols

[0060] 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…Power transmission device, 51…Power transmission coil, 52…Resonance capacitor, 53…Resonance circuit, 55…Impedance circuit, 57…Hall element, 58…Control circuit, 60, 60A - 60D…DC power supply unit, 70…Main power supply device, 71…Filter, 72…PFC circuit, 73…Inverter, 74…Filter, 80…Main power supply, 100…Non - contact power supply system, 200…Power transmission system

Claims

1. A power receiving device (30) that receives power supply in a non-contact manner, comprising: A power receiving coil (31) that receives AC power from the outside in a non-contact manner using magnetic field coupling; A rectifier circuit (34) that rectifies the AC power received by the power receiving coil and converts it into DC, and a first power supply unit (41) that supplies the main power used in the load device; A second power supply unit (42) that is connected in parallel to the power supply line of the first power supply unit in front of the first power supply unit and outputs power for controlling the first power supply unit in DC; A power receiving device comprising the above.

2. The power receiving device according to claim 1, wherein the load device is a device provided in a moving body (20).

3. A filter unit is provided between the power receiving coil and the rectifier circuit, The power receiving device according to claim 1, wherein the filter unit is an impedance filter composed of a reactor (L1 - L4) and a capacitor (CI).

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

5. The power receiving device according to claim 3 or claim 4, further comprising a short - circuit circuit (37) that is controlled by the power output in DC from the second power supply unit and cuts off the power supply to the rectifier circuit, provided in front of the rectifier circuit of the first power supply unit.

6. The rectifier circuit of the first power supply unit is a synchronous rectifier provided with switching elements, and performs short - circuit control to turn on the switching elements (SL1, SL2) provided on one of the power supply lines of the synchronous rectifier at the same time. The power receiving device according to claim 3 or claim 4.

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

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

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

10. The rectifying unit includes a diode (RD1) interposed in one of the power lines and a backflow prevention diode (PD2) interposed in the other of the power lines, and the power receiving device according to claim 8.

11. A power receiving device according to any one of claims 1 to 4, and a power transmitting device (50) including a power transmitting coil (51) that magnetically couples with the power receiving coil when the power receiving coil of the power receiving device approaches and supplies the AC power to the power receiving coil. A non-contact power supply system comprising:

12. The power transmitting device includes a power transmitting side resonance circuit (53) including the power transmitting coil and a power transmitting capacitor (52), the power receiving device includes a power receiving side resonance circuit (33) including the power receiving coil and a power receiving capacitor, and receives the AC power through the power receiving side resonance circuit. The frequency of the AC power is determined corresponding to the resonance frequencies of the power transmitting side resonance circuit and the power receiving side resonance circuit, and the non-contact power supply system according to claim 11.

13. A non-contact power supply method, applying an AC voltage to a power transmitting coil provided in a power transmitting device, providing a first power supply unit that rectifies an alternating current electromagnetically induced in a power receiving coil at a position where magnetic field coupling with the power transmitting coil is possible by a rectifying circuit and converts it into a direct current, and using the direct current output from the first power supply unit as main power for a load device on the power receiving side, providing a second power supply unit connected in parallel to the power supply line of the first power supply unit in front of the rectifying circuit, and outputting, from the second power supply unit, a power smaller than the main power used for controlling the first power supply unit as a direct current. A non-contact power supply method.

Images