Non-contact power supply device and non-contact power supply method

Abstract

To stabilize feeding of AC power to a mobile body.SOLUTION: A non-contact power feeding system 100 comprises: a feeder line 12 through which AC power is fed in non-contact to a power receiver 120 provided in a mobile body 130; and a plurality of feeder panels 10 on which the AC power is generated to be fed through the feeder line 12. On each of the feeder panels 10, a control pulse for controlling generation of the AC power is generated so as to match a center timing of an on-pulse of the control pulse with a timing of the same period defined by a reference clock, and executes PWM control for controlling the AC power fed through the feeder line 12 by changing the width of the on-pulse.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a non-contact power supply device and a non-contact power supply method.

Background Art

[0002] As a conventional non-contact power supply system, for example, the system described in Patent Document 1 below is known. The non-contact power supply system described in Patent Document 1 includes a power supply line and a power supply device that supplies power from a power supply point to the power supply line. In such a configuration, a moving body such as a transport cart can receive power from the power supply line in a non-contact manner.

Prior Art Documents

Patent Documents

[0003] <00​​​​​​​​​​​​​​​​​​​​​​​ To solve the above problems, a contactless power supply device according to one aspect of this disclosure comprises a power supply line that supplies AC power to a power receiving device provided on a mobile body in a contactless manner, and a plurality of power supply panels that generate AC power and supply AC power to the power supply line, and each of the plurality of power supply panels generates a control pulse to control the generation of AC power such that the timing of the center of the on-pulse of the control pulse is the same period defined by a reference clock, and performs PWM control to control the AC power supplied to the power supply line by changing the width of the on-pulse.

[0007] According to the above aspect, it becomes possible to adjust the AC power supplied to the power lines from multiple power distribution panels by PWM control, and it becomes easy to match the phase of the AC power generated by PWM control in each of the multiple power distribution panels. As a result, even if there are differences in the PWM control settings, short-circuit currents will not occur between power distribution panels, and even if the power supply from a power distribution panel stops due to a malfunction or the like, AC power can be supplied to the mobile object via the power lines from the remaining power distribution panels, thereby stabilizing the supply of AC power to the mobile object.

[0008] In one aspect of the above, it is preferable that each of the multiple power supply panels generates control pulses based on a reference clock generated inside one of the multiple power supply panels.

[0009] In this case, the phase of the AC power generated in each of the multiple power distribution panels can be stably synchronized by using a single reference clock as the reference. This further stabilizes the power supplied from the multiple power distribution panels to the mobile device via the power lines.

[0010] Furthermore, in one aspect of the above, it is also preferable to include multiple power lines, multiple power distribution boards, and a power distribution circuit that distributes and supplies the power generated by each of the multiple power distribution boards to the multiple power lines. With such a configuration, even if the power supply from a power distribution board stops due to a malfunction or the like, AC power can be supplied to the mobile body via the multiple power lines from the remaining power distribution boards, thereby stabilizing the supply of AC power to the mobile body that moves over a wide area.

[0011] Alternatively, a contactless power supply method relating to another aspect of the present disclosure supplies AC power generated by multiple power supply panels to a power supply line, and supplies AC power from the power supply line to a power receiving device provided on a mobile body in a contactless manner, wherein each of the multiple power supply panels generates a control pulse to control the generation of AC power such that the timing of the center of the on-pulse of the control pulse is the same period defined by a reference clock, and performs PWM control to control the AC power supplied to the power supply line by changing the width of the on-pulse.

[0012] As described above, the AC power supplied to the power lines from multiple power distribution panels can be adjusted by PWM control, and the phase of the AC power generated by PWM control in each of the multiple power distribution panels can be easily matched among them. As a result, even if there are differences in the PWM control settings, short-circuit currents will not occur between power distribution panels, and even if the power supply from a power distribution panel stops due to a malfunction or the like, AC power can be supplied to the mobile object via the power lines from the remaining power distribution panels, thereby stabilizing the supply of AC power to the mobile object. [Effects of the Invention]

[0013] According to this disclosure, the supply of AC power to a mobile device can be stabilized. [Brief explanation of the drawing]

[0014] [Figure 1] This figure shows the configuration of a contactless power supply system according to one embodiment of the present disclosure. [Figure 2] It is a diagram showing the detailed configuration of the contactless power supply system of FIG. 1. [Figure 3] It is a diagram showing the detailed configuration of the inverter circuit of FIG. 2 and its connection configuration. [Figure 4] It is a diagram showing an example of the waveforms of various signals generated by the power supply panel. [Figure 5] It is a diagram showing an example of the waveform set by PWM control by the power supply panel. [Figure 6] It is a block diagram showing the functional configuration of the synchronization circuit in detail. [Figure 7] It is a block diagram showing the hardware configuration for realizing the synchronization circuit. [Figure 8] It is a diagram showing the connection configuration between the synchronization circuits of multiple power supply panels. [Figure 9] It is a block diagram showing the functional configuration of the MCU of the synchronization circuit. [Figure 10] It is a timing chart for explaining the operation of phase comparison in the synchronization circuit of the power supply panel. [Figure 11] It is a timing chart for explaining the operation of phase adjustment of the reference signal SYNC in the synchronization circuit of the power supply panel. [Figure 12] It is a diagram showing an example of the waveform of the AC voltage generated by PWM control by the power supply panel according to the comparative example.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the description of the drawings, the same reference numerals are assigned to the same elements, and duplicate descriptions are omitted.

[0016] FIG. 1 is a circuit diagram showing the configuration of a non-contact power supply system 100, which is a non-contact power supply device according to an embodiment of the present disclosure. As shown in FIG. 1, the non-contact power supply system 100 of the present embodiment is a power supply system that supplies power to a moving object 130 including a power receiving device 120 in a non-contact manner. Examples of the moving object 130 that is the target of power supply by the non-contact power supply system 100 include a rail-guided carrier that has a built-in motor and travels on a track such as a rail by driving the motor with power received through a power receiving device 120 such as a power receiving coil. The non-contact power supply system 100 of the present embodiment includes a plurality of power supply panels 10, a power distribution circuit 11, and a plurality of power supply lines 12. In the present embodiment, a configuration including three power supply panels 10A, 10B, 10C and three power supply lines 12A, 12B, 12C is illustrated, but the number of power supply panels 10 and the number of power supply lines 12 are not limited to a specific number as long as they are two or more. The power distribution circuit 11 may be provided as a separate device outside the plurality of power supply panels 10, or may be built in any one of the power supply panels 10.

[0017] The power supply panels 10A, 10B, 10C are devices that receive a constant voltage (DC voltage) from a DC power supply and generate AC power, and have a pair of output terminals 13 for outputting the AC power. The pairs of output terminals 13 of the power supply panels 10A, 10B, 10C are electrically connected to the power distribution circuit 11, respectively.

[0018] The power distribution circuit 11 is a circuit that distributes the AC power generated by each of the three power supply panels 10A, 10B, 10C to the three power supply lines 12A, 12B, 12C, and synthesizes and supplies the distributed AC power to each of the three power supply lines 12A, 12B, 12C. This power distribution circuit 11 has a circuit section for distributing and synthesizing AC power and a resonance circuit for resonating and outputting AC power (details will be described later).

[0019] The power lines 12A, 12B, and 12C are transmission lines provided along a track (not shown) on which the mobile body 130 can travel. That is, the power lines 12A, 12B, and 12C are arranged in parallel on a track (not shown) and are electrically insulated from each other. The power lines 12A, 12B, and 12C are composed of a pair of parallel transmission lines 14, the ends of which are electrically connected to the power distribution circuit 11. These power lines 12A, 12B, and 12C supply AC power output from the power distribution circuit 11 to the mobile body 130 via a power receiving device 120 located close to the pair of transmission lines 14. Specifically, the power receiving device 120, which is composed of an E-type core, is attached to the mobile body 130, and the pair of transmission lines 14 are arranged in the gap of the E-type core of the power receiving device 120.

[0020] Next, the details of the configuration of the contactless power supply system 100 will be described with reference to Figures 2 and 3. Figure 2 is a diagram showing the detailed configuration of the contactless power supply system 100 of Figure 1, and Figure 3 is a diagram showing the detailed configuration of the inverter circuit of Figure 2 and its connection configuration.

[0021] Each of the power supply panels 10A, 10B, and 10C includes a synchronous circuit 15, an inverter circuit 16, and a pair of inductor elements 17a and 17b, respectively.

[0022] The inverter circuit 16 is a circuit that converts a constant voltage to an alternating current voltage and is composed of an H-bridge circuit including insulated gate bipolar transistors (IGBTs). Specifically, the inverter circuit 16 includes four IGBTs 18a, 18b, 18c, and 18d, with a constant positive voltage applied to the collectors of IGBTs 18a and 18c, and a constant negative voltage applied to the emitters of IGBTs 18b and 18d, and each emitter of IGBTs 18a and 18c being electrically connected to the collectors of IGBTs 18b and 18d. This inverter circuit 16 operates by applying a clock signal to each of the bases of IGBTs 18a, 18b, 18c, and 18d to generate an alternating current voltage between the two emitters of IGBTs 18a and 18c, which constitute a pair of output terminals. The pair of inductor elements 17a and 17b have one end connected to a pair of output terminals of the inverter circuit 16, and their other ends form a pair of output terminals 13 on the power supply panels 10A, 10B, and 10C.

[0023] The synchronization circuit 15 is a circuit that generates four clock signals to control the operation of the inverter circuit 16. The synchronization circuit 15 is configured to allow the clock signal generation operation to be set to two types: a first operation and a second operation. When set to the first operation, the synchronization circuit 15 generates a reference signal SYNC, which is a clock signal, by dividing the operating clock generated by the built-in crystal oscillator. Based on the generated reference signal SYNC, it generates control signals (clock signals) Va, Vb, Vc, and Vd to be applied to the bases of the IGBTs 18a, 18b, 18c, and 18d in the inverter circuit 16, and applies these control signals Va, Vb, Vc, and Vd to the IGBTs 18a, 18b, 18c, and 18d of the inverter circuit 16. At the same time, the synchronization circuit 15 set to the first operation mode transmits the generated reference signal SYNC to the external power supply panel 10. On the other hand, when set to the second operating mode, the synchronization circuit 15 receives the reference signal SYNC transmitted from the external synchronization circuit 15 set to the first operating mode as the reference signal REF, and adjusts the phase of the reference signal SYNC generated internally in the same manner as above by comparing it with the phase of the reference signal REF. Based on the phase-adjusted reference signal SYNC, it generates control signals (clock signals) Va, Vb, Vc, Vd, and applies these control signals Va, Vb, Vc, Vd to the IGBTs 18a, 18b, 18c, and 18d of the inverter circuit 16. At the same time, the synchronization circuit 15 set to the second operating mode transmits the phase-adjusted reference signal SYNC to the external power supply panel 10.

[0024] The synchronization circuit 15 is configured to drive the inverter circuit 16 using PWM (Pulse Width Modulation) control so that the current supplied to the power supply line 12 is a constant current. In other words, the synchronization circuit 15 monitors the magnitude of the current (AC power) supplied from the resonant circuit 19 (described later) to the multiple power supply lines 12, and performs PWM control so that the magnitude of the monitored current falls within a predetermined range (details will be described later).

[0025] In the contactless power supply system 100 of this embodiment, the synchronization circuit 15 of one of the multiple power supply panels 10 is pre-set to a first operating mode, and the synchronization circuits 15 of the remaining power supply panels 10 are pre-set to a second operating mode. The synchronization circuits 15 of the multiple power supply panels 10 are configured to mutually transmit and receive a reference signal SYNC used to drive the inverter circuit 16.

[0026] The power distribution circuit 11 has a number of resonant circuits 19 corresponding to the number of power supply lines 12, and a connection circuit 20 that electrically connects the resonant circuits 19 to the number of power supply panels 10. The connection circuit 20 is configured to AC-parallel connect a pair of input terminals of each resonant circuit 19 to a pair of output terminals 13 of the number of power supply panels 10 via a capacitor 22. Each of the multiple resonant circuits 19 has a pair of input terminals 21 and a pair of output terminals 23 connected to each of the multiple power supply lines 12. It generates AC power by resonating the AC voltage applied to the pair of input terminals and outputs the generated AC power to each power supply line 12. With this configuration, the AC power generated by each of the multiple power supply panels 10 is distributed to the multiple power supply lines 12, and the distributed AC power is combined for each of the multiple power supply lines 12 and supplied to each power supply line 12.

[0027] Next, examples of waveforms of various signals generated by the power supply panel 10 are shown. Figure 4 shows an example of a waveform when set to the second operating mode, and Figure 5 shows an example of a waveform set by PWM control when set to the first or second operating mode.

[0028] When the power supply panel 10 is set to the second operating mode, it performs a phase comparison between the reference signal REF received from the external power supply panel 10 set to the first operating mode and the internally generated reference signal SYNC, and adjusts the phase of the reference signal SYNC based on the comparison result. Then, the power supply panel 10 set to the second operating mode generates four control signals Va, Vb, Vc, and Vd to synchronize with the phase-adjusted reference signal SYNC, and drives the inverter circuit 16 based on these control signals Va, Vb, Vc, and Vd, causing the inverter circuit 16 to output AC voltages (control pulses) Vu-Vv. The AC voltages Vu-Vv output from the power supply panel 10 are shaped into a smoothly changing AC waveform AC voltage VOUT by passing through the power distribution circuit 11, and the AC voltage VOUT is supplied to the power supply line 12.

[0029] Furthermore, in order to prevent the occurrence of through-current in the inverter circuit 16, the power supply panel 10 generates four control signals Va, Vb, Vc, and Vd so that control signals Va, Vd and control signals Vb, Vc alternately become high levels in synchronization with the reference signal SYNC, while providing pause periods between the on-periods of control signal Va and control signal Vb, and between the on-periods of control signal Vc and control signal Vd. At this time, in order to suppress the back electromotive force of the inductor on the output side of the inverter circuit 16, the power supply panel 10 generates the four control signals Va, Vb, Vc, and Vd so as to provide overlapping periods in which control signals Va and Vc are turned on simultaneously, and overlapping periods in which control signals Vb and Vd are turned on simultaneously.

[0030] Specifically, the synchronization circuit 15 of the power supply panel 10, when set to the first or second operating mode, performs PWM control by changing the time width Wp of the on-pulse of the AC voltage (control pulse) Vu-Vv generated based on the reference signal SYNC (Figure 5). The synchronization circuit 15 generates a reference pulse signal SYNCP based on the reference signal SYNC, which alternately repeats on-pulses and off-pulses synchronized with the periodic pulse timing of the reference signal SYNC. At the same time, the synchronization circuit 15 generates four control signals Va, Vb, Vc, and Vd for controlling the generation of the AC voltage VOUT, such that the timing of the center of the on-pulse of the AC voltage Vu-Vv is the same period timing defined by the on-pulse of the reference pulse signal SYNCP, and the timing of the center of the off-pulse of the AC voltage Vu-Vv is the same period timing defined by the off-pulse of the reference pulse signal SYNCP. In this process, the synchronization circuit 15 performs PWM control by changing the time width Wp of the on-pulse of the AC voltage Vu-Vv while maintaining the timing of the on-pulse center and off-pulse center of the AC voltage Vu-Vv to the same period timing as described above. This makes it possible to adjust the power of the AC voltage VOUT supplied to multiple power lines 12.

[0031] Next, with reference to Figures 6 to 8, the details of the configuration of the synchronization circuit 15 of the power supply panel 10 will be explained. Figure 6 is a block diagram showing the functional configuration of the synchronization circuit 15 in detail, Figure 7 is a block diagram showing the hardware configuration for realizing the synchronization circuit 15, and Figure 8 is a diagram showing the connection configuration between the synchronization circuits 15 of multiple power supply panels 10. Figures 6 to 8 show an example configuration when there are four power supply panels 10 constituting the contactless power supply system 100.

[0032] As shown in Figure 6, the synchronization circuit 15 has, as functional components, an oscillator 24, a selector 25, a driver 26, and three synchronization signal generation units 301, 302, and 303, which include a selector 27, a synchronizer 28, and a variable delay element 29. The synchronization circuit 15 is provided with a number of synchronization signal generation units 301, 302, and 303 equal to the total number of power supply panels 10 minus 1. Here, each of the four power supply panels 10's synchronization circuits 15 is pre-assigned and set to one of four identifiers IDs "0", "1", "2", and "3". The synchronization circuit 15 set to identifier ID "0" is configured to operate in a first operating mode, and the synchronization circuit 15 set to any of identifiers IDs "1", "2", or "3" is configured to operate in a second operating mode. Furthermore, each of the four power supply panels 10's synchronization circuits 15 are connected by communication lines to enable communication with the synchronization circuits 15 of the other three power supply panels 10, and are configured to mutually transmit and receive the reference signal SYNC generated in the synchronization circuits 15 of the four power supply panels 10. In the following description, the reference signal SYNC transmitted from the power supply panel 10 with the identifier ID "0" pre-set will be referred to as reference signal REF0, the reference signal SYNC transmitted from the power supply panel 10 with the identifier ID "1" pre-set will be referred to as reference signal REF1, the reference signal SYNC transmitted from the power supply panel 10 with the identifier ID "2" pre-set will be referred to as reference signal REF2, and the reference signal SYNC transmitted from the power supply panel 10 with the identifier ID "3" pre-set will be referred to as reference signal REF3.

[0033] The oscillator 24 incorporates a crystal oscillator, PLL, frequency divider, etc., and generates a reference signal SYNC, which is a clock signal, by dividing the operating clock generated by the crystal oscillator. For example, the operating clock is set to 20MHz and the reference signal SYNC is set to 8.9kHz.

[0034] The functions of the selector 27, synchronizer 28, and variable delay element 29, which constitute the synchronization signal generation units 301, 302, and 303, will be explained. The selector 27 selects one of the two reference signals REF transmitted from two of the other three power supply panels 10 and inputs it to the synchronizer 28. The variable delay element 29 receives the reference signal SYNC generated by the oscillator 24, or the reference signal SYNC whose phase has been adjusted by the synchronizer 28, samples it internally, and then inputs it to the synchronizer 28 with a delay time corresponding to the transmission delay of the reference signal REF selected by the selector 27. The synchronizer 28 compares the phase of the reference signal REF selected by the selector 27 with the phase of the reference signal SYNC input from the variable delay element 29, and if a phase delay of the reference signal SYNC is detected, it adjusts the reference signal SYNC so as to gradually shorten (vary) the period of the reference signal SYNC generated by the oscillator 24. Conversely, if the synchronizer 28 detects a phase lead in the reference signal SYNC by comparing phases, it adjusts the reference signal SYNC so as to gradually extend (vary) the period of the reference signal SYNC generated by the oscillator 24. At this time, a delay occurs in the phase adjustment process of the reference signal SYNC, which may cause a conflict between the detection of phase delay and the detection of phase lead. In this case, the synchronizer 28 does not perform the phase adjustment process. Furthermore, the synchronizer 28 performs the adjustment process only when it detects a phase difference within a predetermined range. If it detects a phase difference exceeding the predetermined range, or if it cannot detect a level transition of the reference signal REF during one period of the reference signal SYNC, it detects that the reference signal REF has become out of sync (anomaly in synchronization).

[0035] The three synchronization signal generation units 301, 302, and 303 operate the selector 27 to select one of the three reference signals REF received from the external power supply panel 10 from among the four reference signals REF0 to REF3. Furthermore, when the synchronization circuit 15 of the three synchronization signal generation units 301, 302, and 303 is set to the first operating mode, the synchronizers 28 only detect the out-of-sync status of the reference signal REF generated by the external synchronization circuit 15 relative to the reference signal SYNC. On the other hand, when the synchronization circuit 15 is set to the second operating mode, the synchronizer 28 to which the reference signal REF from the external synchronization circuit 15 operating in the first operating mode is selected performs the above-mentioned phase comparison and phase adjustment of the reference signal SYNC, while the other two synchronizers 28 only detect the out-of-sync status of the reference signal REF relative to the reference signal SYNC.

[0036] The selector 25 selects one signal from the reference signal SYNC generated by the oscillator 24 and the reference signal SYNC adjusted by the three synchronizers 28 and inputs it to the driver 26. That is, when the synchronization circuit 15 is set to the first operating mode, the selector 25 selects the reference signal SYNC from the oscillator 24. On the other hand, when the synchronization circuit 15 is set to the second operating mode, the selector 25 selects the reference signal SYNC from the synchronizer 28 that performs phase adjustment of the reference signal SYNC among the three synchronizers 28.

[0037] The driver 26 receives the reference signal SYNC selected and output by the selector 25, generates control signals Va, Vb, Vc, and Vd for driving the inverter circuit 16 in synchronization with the reference signal SYNC, and applies the control signals Va, Vb, Vc, and Vd to the inverter circuit 16. With this configuration, the inverter circuits 16 can be driven so that the phases of the AC power output from the inverter circuits 16 of the four power distribution panels 10 to their respective power lines 12 match, and AC power is supplied by PWM control.

[0038] As shown in Figure 6, the synchronization circuit 15 has signal ports for four reference signals REF0 to REF3. The synchronization circuit 15 activates one of the setting signals EN0 to EN3 according to the identifier ID set in its own power supply panel 10, thereby switching only one of the four signal ports for reference signals REF0 to REF3 to the output port for the reference signal SYNC, and setting the other ports to the input ports for the reference signal REF from the external power supply panel 10. As a result, the reference signal SYNC is output to one of the four signal ports selected from among them.

[0039] As shown in Figure 7, the synchronization circuit 15 is realized by an MCU (Micro Controller Unit) 41, which is a computer system built on an integrated circuit, and an FPGA (Field Programmable Gate Array) 42, which is a device that integrates programmable gates. The FPGA 42 contains UARTs (Universal Asynchronous Receiver / Transmitter) 43a and 43b, which are communication devices that realize asynchronous half-duplex communication between the power supply panels 10. These UARTs 43a and 43b are configured in a redundant configuration along with the communication lines and connectors that connect the power supply panels 10. The circuit sections shown in Figure 6 are built within the FPGA 42. If the MCU 41 has sufficient processing power, it is also possible for the MCU 41 to functionally provide the functions of the synchronization circuit 15. Furthermore, the UARTs 43a and 43b may be built into the MCU 41.

[0040] Referring to Figure 8, the connection configuration between the synchronization circuits 15 of the four power supply panels 10 constituting the contactless power supply system 100 will be described. The synchronization circuits 15 of the four power supply panels 10 are configured to send and receive a reference signal SYNC, a command signal CMD, and a response signal RSP via a transmission path for inter-panel communication. Here, the transmission path for inter-panel communication is redundant, including the communication device, communication line, and connector. That is, the FPGA 42 of one power supply panel 10, which has been pre-set with identifier ID "0", simultaneously transmits the reference signal SYNC generated by its internal oscillator 24 as reference signal REF0 to the FPGA 42s of the other three power supply panels 10. On the other hand, the FPGA 42s of the three power supply panels 10, which have been pre-set with identifier IDs "1", "2", and "3", simultaneously transmit reference signals that have been phase-adjusted based on the reference signal REF0 as reference signals REF1, REF2, and REF3 to the FPGA 42s of the other three power supply panels 10, respectively. The MCUs 41 of the four power supply panels 10 send and receive command signals CMD and response signals RSP to each other, specifying the identifier ID of the destination power supply panel 10.

[0041] Referring to Figure 9, the functional configuration of the MCU 41 of the synchronization circuit 15 will be described. The MCU 41 includes an abnormality detection unit 51, a change control unit 52, and a measurement unit 53 as its functional components.

[0042] The abnormality detection unit 51 determines abnormalities in each of the multiple power supply panels 10 based on the state of the reference signal SYNC generated in its own power supply panel 10 and the reference signal REF received from other power supply panels 10. For example, if the synchronization circuit 15 detects a synchronization abnormality in the reference signal REF, the abnormality detection unit 51 determines that a synchronization abnormality has occurred in the other power supply panel 10 corresponding to that reference signal REF. At that time, the abnormality detection unit 51 exchanges the synchronization abnormality determination results for the multiple power supply panels 10 with the multiple power supply panels 10 using the command signal CMD and the response signal RSP. The abnormality detection unit 51 then determines the consistency of the determination results among the multiple power supply panels 10 and identifies whether each of the multiple power supply panels 10 has a fault based on that determination result. For example, the abnormality detection unit 51 identifies a fault in a circuit or transmission line of a certain power supply panel 10 based on the discrepancy with the synchronization abnormality determination results of other power supply panels 10. Furthermore, the abnormality detection unit 51 identifies a fault in the circuit or transmission line of a power supply unit 10 that has been simultaneously determined to have a synchronization abnormality by multiple power supply units 10.

[0043] Furthermore, the abnormality detection unit 51 also has the function of determining abnormalities in multiple power supply panels 10 based on the communication status of the command signal CMD and response signal RSP transmitted and received as heartbeat commands between the multiple power supply panels 10. Specifically, the abnormality detection unit 51 of the synchronization circuit 15 set to the first operating mode periodically transmits the command signal CMD to other power supply panels 10, and the abnormality detection unit 51 of the synchronization circuit 15 of the other power supply panels 10 replies with a response signal RSP in response. Then, the abnormality detection unit 51 of the synchronization circuit 15 set to the first operating mode identifies an abnormality in the other power supply panels 10 set to the second operating mode based on the reception status of the response signal RSP. At this time, the abnormality detection unit 51 may also identify abnormalities in multiple power supply panels 10, including its own power supply panel 10, by combining the above-mentioned determination result of the synchronization abnormality of the power supply panel 10.

[0044] Furthermore, the abnormality detection unit 51 also has the function of detecting a malfunction in the inverter circuit 16 within its own power supply panel 10 by monitoring the output current of the inverter circuit 16.

[0045] The change control unit 52 has the function of changing the operating mode of multiple power supply panels 10 based on the abnormality detection result from the abnormality detection unit 51. Specifically, if an abnormality is detected in its own power supply panel 10 and it is set to the first operating mode, the change control unit 52 stops the output of the reference signal SYNC and the reference signal REF to stop supplying AC power, and broadcasts a command signal CMD to one of the other power supply panels 10 to change it to the first operating mode. In response, the change control unit 52 of the other power supply panels 10 controls it to either change to the synchronization process of the first operating mode or to change the reference signal REF of the synchronization target in the second operating mode. Furthermore, if an abnormality is detected in its own power supply panel 10 and it is set to the second operating mode, the change control unit 52 stops the output of the reference signal SYNC and the reference signal REF to stop supplying AC power.

[0046] Furthermore, if the change control unit 52 detects an abnormality in another power supply panel 10, and that other power supply panel 10 is set to the first operating mode, and its own power supply panel 10 should be set to the first operating mode next, it broadcasts a command signal CMD for changing the operating mode to the other power supply panel 10 and controls its own power supply panel 10 to change to the first operating mode. In response, the other power supply panel 10 controls itself to change the synchronization target in the second operating mode, and the power supply panel 10 that was operating in the first operating mode stops supplying power. Also, if the change control unit 52 detects an abnormality in another power supply panel 10 and that power supply panel 10 is set to the second operating mode, it sends a command signal CMD to that power supply panel 10 to notify it of the abnormality detection. In response, that power supply panel 10 stops outputting the reference signal SYNC and the reference signal REF, and stops supplying AC power.

[0047] The measurement unit 53 measures the transmission delay of the reference signal SYNC between multiple power supply panels 10, and based on this, sets the delay time of multiple variable delay elements 29 in the synchronization circuit 15. Specifically, as part of the initialization process when the contactless power supply system 100 is started, the measurement unit 53 sends a reference signal REF from its own power supply panel 10 to other power supply panels 10, measures the delay time of the reference signal REF returned from the other power supply panels 10, and calculates half of that delay time as the transmission delay time (latency) between its own power supply panel 10 and the other power supply panels 10. The measurement unit 53 repeats this measurement to calculate the latency between its own power supply panel 10 and the other power supply panels 10, and based on this latency value (calibration value), sets the delay time of the variable delay elements 29 used for phase comparison of the reference signal REF from each of the other power supply panels 10. Each of the measurement units 53 of the multiple power supply panels 10 performs the above delay time setting process during the initialization process.

[0048] Figure 10 is a timing chart illustrating the phase comparison operation in the synchronization circuit 15 of the power supply panel 10. In this way, the synchronization circuit 15 of the power supply panel 10 receives a signal REF1 that is delayed by a path delay including the propagation delay in the transceiver ICs built into the multiple power supply panels 10 and the transmission delay in the transmission line for inter-panel communication, and a reference signal REF2 that is further delayed by the sampling latency in the synchronization circuit 15, from the other power supply panels 10. The synchronization circuit 15 adjusts the reference signal SYNC, which is generated or phase-adjusted internally, by delaying it by a time corresponding to the calibration value calculated by the measurement unit 53 to obtain the reference signal SYNC1, and then performs a phase comparison between the reference signal SYNC1 and the reference signal REF2.

[0049] Figure 11 is a timing chart illustrating the phase adjustment operation of the reference signal SYNC in the synchronization circuit 15 of the power supply panel 10 operating in the second operating mode, where (a) is the timing chart when a delay in the reference signal SYNC1 is detected, and (b) is the timing chart when a lead in the reference signal SYNC1 is detected. In this way, when the synchronization circuit 15 detects a phase delay in the reference signal SYNC1 after the delay time has been added relative to the reference signal REF from the power supply panel 10 operating in the first operating mode, it controls the oscillator 24 to gradually shorten the period of the reference signal SYNC. On the other hand, when the synchronization circuit 15 detects a phase lead in the reference signal SYNC1 after the delay time has been added relative to the reference signal REF from the power supply panel 10 operating in the first operating mode, it controls the oscillator 24 to gradually extend the period of the reference signal SYNC. As a result, the synchronization circuit 15 can adjust the phase of the reference signal SYNC so that the phase of the reference signal SYNC matches the phase of the reference signal REF before the occurrence of path delay.

[0050] Next, the procedure for a contactless power supply method using the contactless power supply system 100 according to this embodiment will be described.

[0051] When one of the power supply panels 10 constituting the contactless power supply system 100 is activated, a command signal CMD for activation is sent from that power supply panel 10 to the other power supply panels 10. In response, the synchronization processing mode in the synchronization circuit 15 of each of the power supply panels 10 is set.

[0052] Subsequently, the synchronization circuit 15 of one of the power supply panels 10, which is set to the first operating mode, drives the inverter circuit 16 of that power supply panel 10 by PWM control based on the reference signal SYNC generated by the internal oscillator 24, and the power supply panel 10 begins supplying AC power to the multiple power lines 12. At the same time, the synchronization circuit 15 of the power supply panel 10 set to the first operating mode transmits the reference signal SYNC as a reference signal REF to the other power supply panels 10.

[0053] In response, the synchronization circuits 15 of the other power supply panels 10, excluding the first power supply panel 10, perform a phase comparison between the reference signal SYNC generated by the internal oscillator 24 and the reference signal REF transmitted from the first power supply panel 10, thereby adjusting the phase of the reference signal SYNC. Then, the synchronization circuits 15 of the other power supply panels 10 drive the inverter circuits 16 of the other power supply panels 10 by PWM control based on the phase-adjusted reference signal SYNC, and the supply of AC power from the other power supply panels 10 to the multiple power supply lines 12 begins.

[0054] The effects obtained by the contactless power supply system 100 and the contactless power supply method using the same, as described above, will now be explained.

[0055] According to this embodiment, it is possible to adjust the AC power supplied from multiple power distribution panels 10 to the power supply line 12 by PWM control, and it is also easy to match the phase of the AC power generated by PWM control in each of the multiple power distribution panels 10. As a result, even if there are differences in the PWM control settings, a short-circuit current will not occur between the power distribution panels, and even if the power supply from a power distribution panel 10 stops due to a malfunction or the like, AC power can be supplied to the mobile body 130 via the power supply line 12 from the remaining power distribution panels 10, thereby stabilizing the supply of AC power to the mobile body 130.

[0056] Figure 12 shows an example of the waveform of the AC voltage Vu-Vv generated by PWM control by a power supply panel according to the comparative example. In this comparative example, when the power supply panel performs PWM control, it generates four control signals Va, Vb, Vc, and Vd for the AC voltage Vu-Vv such that the rising edge timing of the on-pulse of the AC voltage Vu-Vv is the same period timing defined by the on-pulse of the reference pulse signal SYNCP. At the same time, the power supply panel according to the comparative example controls the falling edge timing of the on-pulse of the AC voltage Vu-Vv to change the time width Wp of the on-pulse of the AC voltage Vu-Vv while maintaining the rising edge timing of the on-pulse at the same period. According to this comparative example, when the time width Wp is changed by PWM control, the phase of the AC voltage VOUT supplied to the power supply line 12 also changes. In contrast, according to this embodiment, it is possible to avoid the phase of the AC voltage VOUT relative to the reference signal SYNC changing due to the execution of PWM control. As a result, the phase of the AC power supplied from multiple power distribution panels 10 to the power supply line 12 can be stably matched.

[0057] Furthermore, this embodiment includes a plurality of power supply lines 12, a plurality of power supply panels 10, and a power distribution circuit 11 that distributes and supplies the power generated by each of the plurality of power supply panels 10 to the plurality of power supply lines 12. With this configuration, even if the power supply from a power supply panel 10 stops due to a malfunction or the like, AC power can be supplied to the mobile body 130 via the plurality of power supply lines 12 from the remaining power supply panels 10, thereby stabilizing the supply of AC power to the mobile body 130 that moves over a wide area.

[0058] In this embodiment, one power supply panel 10, which is pre-set to a first operating mode, generates AC power based on a self-generated reference signal SYNC, and the other power supply panels 10, which are pre-set to a second operating mode, generate AC power that matches the phase of the AC power generated by the first power supply panel 10, based on a self-generated reference signal SYNC and a reference signal REF generated by the first power supply panel 10. This makes it possible to align the phase of the AC power supplied to the power supply line 12 from the multiple power supply panels 10, and to efficiently supply power from the power supply panels 10 to the mobile unit 130.

[0059] Furthermore, in this embodiment, the other power supply unit 10 drives the inverter circuit 16 by changing the period of the reference signal SYNC based on the phase comparison result between the reference signal REF received from the first power supply unit 10 and the reference signal SYNC generated internally. With this configuration, the phase of the reference signal SYNC of the other power supply unit 10 can be adjusted efficiently, and the process of adjusting the phase of the AC power generated by the other power supply unit 10 relative to the phase of the AC power generated by the first power supply unit 10 can be made more efficient.

[0060] Furthermore, in this embodiment, the multiple power supply panels 10 are configured to send and receive a reference signal SYNC generated internally to each other, and each of the multiple power supply panels 10 is configured to determine an abnormality in the other power supply panels 10 based on the reference signal SYNC received from the other power supply panels 10. In this case, the multiple power supply panels 10 can efficiently detect abnormalities in the other power supply panels 10.

[0061] Furthermore, in this embodiment, the multiple power supply panels 10 operate to change the power supply panel 10 set to the first operating mode when an abnormality is detected in one of the power supply panels 10 set to the first operating mode. With this configuration, the process of adjusting the phase of AC power among the multiple power supply panels 10 can be stabilized, and the power supply to the mobile unit 130 can be reliably stabilized.

[0062] Furthermore, in this embodiment, the multiple power supply panels 10 operate to determine abnormalities based on at least one of the state of the reference signal REF and the communication state between them and other power supply panels 10. In this case, abnormalities in other power supply panels 10 can be efficiently determined.

[0063] Furthermore, in this embodiment, each of the multiple power supply panels 10 has a function to measure the transmission delay of the reference signal REF between itself and other power supply panels 10, and operates to set a calibration value for controlling the phase of AC power based on the transmission delay. With this configuration, the phase of AC power can be adjusted taking into account the transmission delay between the multiple power supply panels 10, and the power supply to the mobile unit 130 can be further stabilized.

[0064] Furthermore, in this embodiment, the multiple power supply panels 10 drive the inverter circuit 16 so that the phases of the AC power match, based on the comparison result of the phase of the reference signal REF and the phase of the reference signal SYNC, which is delayed according to the calibration value. In this case, by comparing the phases of the reference signal SYNC while taking into account the transmission delay between the multiple power supply panels 10, the phase of the AC power can be adjusted more precisely.

[0065] While the principles of this disclosure have been illustrated and described above in preferred embodiments, it will be recognized by those skilled in the art that this disclosure can be modified in arrangement and detail without departing from such principles. This disclosure is not limited to the specific configurations disclosed in these embodiments. Accordingly, all modifications and changes arising from the scope of the claims and their spirit are claimed. [Explanation of symbols]

[0066] 100... Contactless power supply system (contactless power supply device), 10, 10A, 10B, 10C... Power supply panel, 11... Power distribution circuit, 12, 12A, 12B, 12C... Power supply line, 16... Inverter circuit, 51... Anomaly detection unit, 52... Change control unit, 53... Measurement unit, 120... Power receiving device, 130... Mobile unit, SYNC... Reference signal, REF... Reference signal, Va, Vb, Vc, Vd... Control signals (clock signals).

Claims

1. Multiple power lines that supply AC power to a power receiving device installed on a mobile body in a non-contact manner, Multiple power distribution panels that generate AC power and supply the AC power to the power supply line, The system includes a power distribution circuit that distributes and supplies power generated by each of the plurality of power distribution panels to the plurality of power lines, Each of the plurality of power supply panels generates a control pulse to control the generation of the AC power such that the timing of the center of the on-pulse of the control pulse is the same period defined by a reference clock, and performs PWM control to control the AC power supplied to the power supply line by changing the width of the on-pulse. Contactless power supply device.

2. Each of the plurality of power supply panels generates the control pulse based on a reference clock generated inside one of the plurality of power supply panels. The contactless power supply device according to claim 1.

3. AC power generated by each of the multiple power distribution boards is distributed and supplied to multiple power lines using a power distribution circuit, and AC power is supplied non-contact from the multiple power lines to a power receiving device provided on a mobile body, Each of the plurality of power supply panels generates a control pulse to control the generation of the AC power such that the timing of the center of the on-pulse of the control pulse is the same period defined by a reference clock, and performs PWM control to control the AC power supplied to the power supply line by changing the width of the on-pulse. A contactless power supply method.

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