Power receiving device and non-contact power supply system

Abstract

A conveyor system 1 is provided with: a power receiving unit 310 that receives electric power in a contactless manner; a step-up / step-down chopper 311 that controls the electric power supplied from the power receiving unit 310 and that supplies the controlled electric power to a load; a capacitor unit 312 that is charged with the electric power supplied from the power receiving unit 310 and that supplies the electric power to the load via the step-up / step-down chopper 311; and a bypass circuit 314 that causes the electric power to be supplied from the power receiving unit 310 to the capacitor unit 312 while detouring the step-up / step-down chopper 311. The bypass circuit 314 causes the electric power to be supplied from the power receiving unit 310 to the capacitor unit 312 via the bypass circuit 314 when the voltage of the capacitor unit 312 is less than or equal to a first prescribed value.

Description

[Technical field]

[0001] The present invention relates to a power receiving device and a contactless power supply system. [Background technology]

[0002] Patent Document 1 discloses an inrush current prevention circuit for an AC / DC power supply device having a rectifier that rectifies alternating current and a smoothing capacitor that smoothes the output of the rectifier, the inrush current prevention circuit comprising: signal output means for outputting a signal according to the current value of the current flowing into the smoothing capacitor; and variable impedance means inserted between the rectifier and the smoothing capacitor for changing impedance according to the signal so that the inrush current does not flow into the smoothing capacitor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-32982 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above conventional device, the inflow current is adjusted by a variable impedance means (transistor) to prevent the occurrence of an inrush current due to a charge current flowing into a smoothing capacitor. In the conventional device, for example, when the capacitor has a large capacity, it is necessary to adjust the current value of the inflow current for a long period of time to prevent the occurrence of an inrush current. However, in the conventional device, adjusting the current value of the inflow current for a long period of time can cause the circuit to generate a lot of heat. Therefore, it is difficult to continue to prevent the occurrence of an inrush current for a long period of time.

[0005] An object of one aspect of the present invention is to provide a power receiving device and a contactless power supply system that can prevent the occurrence of an inrush current over a long charging time. [Means for solving the problem]

[0006] A power receiving device according to one aspect of the present invention includes a power receiving unit that receives power wirelessly from a power source that supplies power with a constant current value, a buck-boost chopper connected to the power receiving unit and controls the power supplied from the power receiving unit and supplies it to a load, an auxiliary power source connected to the buck-boost chopper and supplies power to the load via the buck-boost chopper, and a bypass unit that supplies power from the power receiving unit to the auxiliary power source, bypassing the buck-boost chopper, and the bypass unit supplies power from the power receiving unit to the auxiliary power source via the bypass unit when the voltage of the auxiliary power source is equal to or lower than a first predetermined value.

[0007] In a power receiving device according to one aspect of the present invention, when the voltage of the auxiliary power supply is equal to or lower than a first predetermined value, the bypass section causes power to be supplied from the power receiving section to the auxiliary power supply via the bypass section. During initial charging of the auxiliary power supply, the voltage of the auxiliary power supply is equal to or lower than the first predetermined value. In the power receiving device, by supplying power from the power receiving section to the auxiliary power supply via the bypass section during initial charging of the auxiliary power supply, it is possible to prevent an inrush current exceeding a certain current value (steady-state current value) from being generated in the auxiliary power supply from the power receiving section during initial charging (when the power supply is turned on). Also, unlike conventional devices, the power receiving device does not need to adjust the current value of the inflow current, and therefore heat generation during charging can be suppressed. Therefore, the power receiving device can prevent an inrush current from being generated over a long charging time.

[0008] In one embodiment, the bypass unit includes a switching unit that switches on / off the supply of power from the power receiving unit to the auxiliary power supply via the bypass unit, and the switching unit is turned on when a predetermined condition is satisfied, causing power to be supplied from the power receiving unit to the auxiliary power supply via the bypass unit, and is turned off when the predetermined condition is not satisfied, causing power supply from the power receiving unit to the auxiliary power supply via the bypass unit, and the predetermined condition may include a case where the voltage of the auxiliary power supply is equal to or lower than a first predetermined value. In this configuration, by switching on / off by the switching unit, power can be supplied from the power receiving unit to the auxiliary power supply via the bypass unit when the voltage of the auxiliary power supply is equal to or lower than the first predetermined value.

[0009] In one embodiment, the predetermined condition may include a case where the input voltage of the buck-boost chopper is equal to or lower than a second predetermined value, and the switching unit may be turned on when the voltage of the auxiliary power supply is equal to or lower than the first predetermined value and the input voltage of the buck-boost chopper is equal to or lower than the second predetermined value. In this configuration, it is possible to prevent a large voltage from being applied to the bypass unit.

[0010] In one embodiment, the predetermined condition may include a case where the output voltage of the buck-boost chopper is equal to or greater than a third predetermined value, and the switching unit may be turned on when the voltage of the auxiliary power supply is equal to or less than the first predetermined value, the input voltage of the buck-boost chopper is equal to or less than a second predetermined value, and the output voltage of the buck-boost chopper is equal to or greater than the third predetermined value. In this configuration, the auxiliary power supply can be charged after power is supplied to the buck-boost chopper.

[0011] In one embodiment, the bypass unit may be a circuit including a comparator. In this configuration, the operating voltage can be increased and the circuit can be made less susceptible to noise.

[0012] A contactless power supply system according to one aspect of the present invention includes the above-described power receiving device, and a power transmitting device that transmits power having a constant current value to the power receiving device.

[0013] A contactless power transfer system according to an aspect of the present invention includes the power receiving device described above. Accordingly, the contactless power transfer system can prevent the occurrence of inrush current over a long charging time.

[0014] In one embodiment, the power transmitting device may have a power supply line provided along the track rail, and the power receiving device may be provided in a traveling vehicle that travels on the track rail. In this configuration, when the contactless power supply system is applied to a transportation system, it is possible to prevent the occurrence of inrush current over a long charging time. Effect of the Invention

[0015] According to one aspect of the present invention, it is possible to prevent the occurrence of inrush current over a long charging time. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram illustrating a schematic diagram of a track of a transport system according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing a configuration of the contactless power supply device. [Diagram 3] FIG. 3 is a diagram illustrating a configuration of the power receiving device. [Figure 4] FIG. 4 is a diagram illustrating a configuration of a voltage monitoring unit of the bypass circuit. [Diagram 5] FIG. 5 is a timing chart showing the operation of the power receiving device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or corresponding elements are designated by the same reference numerals, and duplicated explanations will be omitted.

[0018] As shown in Fig. 1, the conveying system (non-contact power supply system) 1 includes a non-contact power supply device (power transmission device) 10 and an overhead conveying vehicle (traveling vehicle) 30. The conveying system 1 is a system for conveying an article (not shown) using the overhead conveying vehicle 30 that can travel along a track rail T. In the conveying system 1, power is supplied to the overhead conveying vehicle 30 in a non-contact manner from power supply lines 21A, 21B provided on the track rail T. The overhead conveying vehicle 30 uses the supplied power to drive the overhead conveying vehicle 30 or drive various devices provided on the overhead conveying vehicle 30.

[0019] The overhead transport vehicle 30 includes, for example, a ceiling-suspended crane, an OHT (Overhead Hoist Transfer), etc. The goods include, for example, a container for storing a plurality of semiconductor wafers, a container for storing glass substrates, a reticle pod, an FOSB, an SMIF Pod, general parts, etc. Here, a transport system 1 in which the overhead transport vehicle 30 travels along a track rail T installed on the ceiling of a factory or the like will be described as an example.

[0020] The track rail T is, for example, a circular track. The power feeders 21A and 21B are supplied with power from the non-contact power feeder 10. The power feeders 21A and 21B are arranged below the track rail T in the traveling direction of the ceiling transport vehicle 30, on at least one of the right and left sides of the track center. Note that the power feeder 21B is arranged below the power feeder 21A, and therefore overlaps below the power feeder 21A in FIG. 1.

[0021] The arrangement of the power feeders 21A, 21B relative to the track rail T is changed by the switching unit 40. The power feeders 21A, 21B are arranged on the left side of the track rail T in an initial area connected to the non-contact power supply device 10. When the ceiling transport vehicle 30 travels on the track rail T, the arrangement of the power feeders 21A, 21B is switched from the left side to the right side of the track rail T by the switching unit 40. By arranging the power feeders 21A, 21B on the right side of the track rail T, it is possible to continuously supply power even when the ceiling transport vehicle 30 travels on a branch line TA branched off from the track rail T, as shown in FIG. 1 .

[0022] 2, the non-contact power supply device 10 supplies power to the ceiling transport vehicle 30 in a non-contact manner. The non-contact power supply device 10 supplies power with a constant current value. The non-contact power supply device 10 includes a power source 11, a molded case circuit breaker 12, a noise filter 13, a power factor correction device 14, a rectifier 15, a smoother 16, an inverter 17, a filter circuit 18, a first current sensor 19, a second current sensor 20, power supply lines 21A and 21B, and a control device 22. The noise filter 13, the power factor correction device 14, the rectifier 15, and the smoother 16 configure a power converter 25.

[0023] The power source 11 is a facility that supplies AC power such as a commercial power source, and supplies AC power (three-phase 200V). The frequency of the AC power is, for example, 50 Hz or 60 Hz. The molded-case circuit breaker 12 opens the electrical circuit when an overcurrent flows. The noise filter 13 removes noise from the AC power. The power factor correction device 14 improves the power factor by making the input current closer to a sine wave. The rectifier 15 converts the AC power supplied from the power source 11 (power factor correction device 14) into DC power. The smoother 16 smoothes the DC power converted in the rectifier 15. The power converter 25 may further have a step-up / step-down function.

[0024] The inverter 17 converts the DC power output from the smoother 16 into AC power and outputs it to the filter circuit 18. The inverter 17 has a plurality of switching elements 23. The switching elements 23 are elements that can be electrically switched between open and closed states.

[0025] The filter circuit 18 is provided between the inverter 17 and the power supply lines 21A and 21B. The filter circuit 18 suppresses harmonic noise. The filter circuit 18 has a reactor RT1, a capacitor C0, a capacitor C1, a reactor RT2, and a capacitor C2. The reactor RT1 and the capacitor C0 are connected in series to form a first resonant circuit RC1. The reactor RT2 and the capacitor C2 are connected in series to form a second resonant circuit RC2. The first resonant circuit RC1 and the second resonant circuit RC2 are connected in series. The capacitor C1 is connected in parallel to the first resonant circuit RC1 and the second resonant circuit RC2.

[0026] The first current sensor 19 detects a current I1 (inverter current) output from the inverter 17, i.e., flowing through the inverter 17. The first current sensor 19 outputs a first current signal indicative of the detected current I1 to the control device 22. The second current sensor 20 detects a current I2 (power supply current) of the AC power passing through the second resonant circuit RC2. The second current sensor 20 outputs a second current signal indicative of the detected current I2 to the control device 22.

[0027] The power feeders 21A and 21B form coils for contactlessly feeding power to a power receiving unit 310a (described later) of the ceiling transport vehicle 30. The power feeders 21A and 21B generate magnetic flux when AC power is supplied from the filter circuit 18. The power feeders 21A and 21B have an inductance RL. In this embodiment, the AC currents flowing through the multiple power feeders 21A and 21B are not in phase with each other.

[0028] The control device 22 controls the operation of the inverter 17. The control device 22 is a computer system or a processor implemented in an integrated circuit. The control device 22 is composed of a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and an input / output interface, etc. Various programs and data are stored in the ROM.

[0029] The control device 22 has a control unit 24. The control device 22 is connected to the first current sensor 19 and the second current sensor 20 of the filter circuit 18. The control device 22 receives a first current signal and a second current signal output from the first current sensor 19 and the second current sensor 20, respectively.

[0030] The control unit 24 controls the inverter 17 to control the magnitude of AC power supplied to the power feeders 21A and 21B, and thereby controls the magnitude of power supplied to the ceiling transport vehicle 30. In this embodiment, the power control is performed using phase shift control. The control unit 24 performs power control based on the first current signal and the second current signal output from the first current sensor 19 and the second current sensor 20, respectively, so that the value of the power transmitted to the ceiling transport vehicle 30 becomes a target value. As a result, power with a constant current value is supplied to the ceiling transport vehicle 30.

[0031] As shown in Fig. 1, the ceiling transport vehicle 30 travels along a track rail T to transport an article. The ceiling transport vehicle 30 is configured to be capable of transferring an article. The number of the ceiling transport vehicles 30 provided in the transport system 1 is not particularly limited and may be more than one.

[0032] As shown in FIG. 3, the ceiling transport vehicle 30 includes a power receiving device 31, a driving device 32, a transfer device 33, and a control device .

[0033] The power receiving device 31 wirelessly receives power transmitted from the wireless power supply device 10. The power receiving device 31 supplies the received power to the drive device 32, the transfer device 33, and the control device 34. The power receiving device 31 has a power receiving unit 310, a step-up / step-down chopper 311, a capacitor unit (auxiliary power source) 312, a bidirectional power source 313, and a bypass circuit (bypass section) 314. The power receiving device 31 also includes a capacitor C11 and a capacitor C12. The capacitors C11 and C12 are smoothing capacitors.

[0034] The power receiving unit 310 receives power from the power feed lines 21A and 21B in a non-contact manner. The power receiving unit 310 includes a power receiving section 310a and a parallel resonant section 310b. The power receiving section 310a is a coil for receiving power. Magnetic flux generated by the power feed lines 21A and 21B interlinks with the power receiving section 310a, thereby generating AC power in the power receiving section 310a. The power receiving section 310a supplies the AC power to the parallel resonant section 310b. The parallel resonant section 310b rectifies the high-frequency current of the AC power supplied from the power receiving section 310a, and generates DC power (hereinafter simply referred to as "power"). The parallel resonant section 310b is configured to include a capacitor, a diode, and the like. The parallel resonant section 310b outputs power.

[0035] The buck-boost chopper 311 controls power. The buck-boost chopper 311 boosts or lowers the voltage of the power supplied from the power receiving unit 310 or the capacitor unit 312. The buck-boost chopper 311 includes a capacitor, a diode, an inductor, and the like. The buck-boost chopper 311 is connected to the power receiving unit 310. The buck-boost chopper 311 supplies power to a load such as the drive device 32.

[0036] The capacitor unit 312 performs charging and discharging. The capacitor unit 312 is charged with power supplied from the power receiving unit 310, and is also charged with regenerative power supplied via the bidirectional power supply 313. The capacitor unit 312 discharges as necessary to assist power supply to a load such as the drive device 32. The capacitor unit 312 includes a plurality of capacitors. The capacitance of the capacitor unit 312 is, for example, 30 F. The capacitor unit 312 is connected to the power receiving unit 310 and the step-up / step-down chopper 311. Specifically, the input end of the capacitor unit 312 is connected to the output side of the power receiving unit 310 and the input side of the step-up / step-down chopper 311 by the connection lines L1, L3, and L2. A switch 318 is provided between the connection line L1 and the connection line L3.

[0037] The bidirectional power supply 313 converts DC and AC in both directions. The bidirectional power supply 313 includes a bidirectional DC / DC converter. An output end of the bidirectional power supply 313 is connected to the output side of the power receiving device 31. The bidirectional power supply 313 converts regenerative power from a load (such as a motor) and supplies the power to the capacitor unit 312.

[0038] Bypass circuit 314 bypasses the power supplied from power receiving unit 310. Bypass circuit 314 causes power to be supplied from power receiving unit 310 to capacitor unit 312, bypassing step-up / step-down chopper 311. When a predetermined condition is satisfied, bypass circuit 314 causes power to be supplied from power receiving unit 310 to capacitor unit 312 via bypass circuit 314. Bypass circuit 314 is connected between power receiving unit 310 and capacitor unit 312, without passing through step-up / step-down chopper 311.

[0039] 3 and 4, the bypass circuit 314 has a first comparator circuit 315, a second comparator circuit 316, a third comparator circuit 317, and a switch (switching unit) 318. The first comparator circuit 315, the second comparator circuit 316, and the third comparator circuit 317 configure a voltage monitoring unit 319.

[0040] The first comparator circuit 315 monitors the input voltage of the buck-boost chopper 311. The first comparator circuit 315 includes a first comparator CP1, resistors R11, R12, and R13, and a diode D11. The input voltage of the buck-boost chopper 311 is input to a first terminal (non-inverting input) of the first comparator CP1 via a connection line L4. The connection line L4 is connected to the input side of the buck-boost chopper 311. Note that, although the connection line L4 is connected to a position different from the connection line L1 on the input side of the buck-boost chopper 311 in FIG. 3, they are actually connected to the same position.

[0041] The second terminal (inverting input) of the first comparator CP1 is a reference terminal, to which a voltage of a second predetermined value is input. In this embodiment, the second predetermined value is 60V. The first comparator circuit 315 outputs a comparison result (voltage). The comparison result output from the first comparator circuit 315 is output to the switch 318 via the NOT gate G1 and the connection line L5.

[0042] The second comparator circuit 316 monitors the output voltage of the step-up / step-down chopper 311. The second comparator circuit 316 includes a second comparator CP2, resistors R21, R22, and R23, and a diode D21. The output voltage of the step-up / step-down chopper 311 is input to a first terminal of the second comparator CP2 via a connection line L6. The connection line L6 is connected to the output side of the step-up / step-down chopper 311. The second terminal of the second comparator CP2 is a reference terminal, and a voltage of a third predetermined value is input to the second terminal. In this embodiment, the third predetermined value is 320V. The comparison result output from the second comparator circuit 316 is output to the switch 318 via a buffer amplifier G2 and a connection line L5.

[0043] The third comparator circuit 317 monitors the voltage of the capacitor unit 312. The third comparator circuit 317 includes a third comparator CP3, resistors R31, R32, and R33, and a diode D31. The voltage of the capacitor unit 312 is input to a first terminal of the third comparator CP3 via a connection line L7. The connection line L7 is connected to the input side (connection line L3) of the capacitor unit 312. The second terminal of the third comparator CP3 is a reference terminal, and a voltage of a first predetermined value is input. In this embodiment, the first predetermined value is 60V. The comparison result output from the third comparator circuit 317 is output to the switch 318 via a NOT gate G3 and a connection line L5. Note that in FIG. 3, the connection line L7 is connected to a position different from the input end of the capacitor unit 312, but is actually connected to the input end of the capacitor unit 312.

[0044] The switch 318 switches on / off the supply of power from the power receiving unit 310 to the capacitor unit 312. The switch 318 is, for example, a field effect transistor (FET). The switch 318 is turned on when a predetermined condition is satisfied, and causes the power receiving unit 310 to supply power to the capacitor unit 312. The switch 318 is turned off when the predetermined condition is not satisfied, and causes the power supply from the power receiving unit 310 to the capacitor unit 312 to be stopped. The switch 318 switches on / off based on the comparison results output from the first comparator circuit 315, the second comparator circuit 316, and the third comparator circuit 317. When the switch 318 is turned on, power is supplied from the power receiving unit 310 to the capacitor unit 312. When the switch 318 is turned off, power is not supplied from the power receiving unit 310 to the capacitor unit 312.

[0045] The switch 318 is turned on when the comparison result output from the first comparator circuit 315 is 60 V or less, the comparison result output from the second comparator circuit 316 is 320 V or more, and the comparison result output from the third comparator circuit 317 is 60 V or less. That is, the switch 318 is turned on when the following predetermined conditions are satisfied: (1) the input voltage of the buck-boost chopper 311 is 60 V or less, (2) the output voltage of the buck-boost chopper 311 is 320 V or more, and (3) the voltage of the capacitor unit 312 is 60 V or less.

[0046] The switch 318 is turned off when the comparison result output from the first comparator circuit 315 is greater than 60 V, the comparison result output from the second comparator circuit 316 is less than 320 V, or the comparison result output from the third comparator circuit 317 is greater than 60 V. In other words, the switch 318 is turned off when the above-mentioned (1), (2), or (3) is not satisfied as the predetermined condition.

[0047] The operation of power receiving device 31 during initial charging of capacitor unit 312 will be described with reference to Fig. 5. During initial charging, switch 318 is off. That is, power is not supplied from power receiving unit 310 to capacitor unit 312. Fig. 5 shows the voltage of power receiving unit 310, the output voltage of buck-boost chopper 311, the input voltage of buck-boost chopper 311, the voltage of capacitor unit 312, and the on / off state of switch 318.

[0048] As shown in FIG. 5, in the power receiving device 31, when the power receiving unit 310 starts receiving power from the power feeder lines 21A and 21B, the input voltage and output voltage of the buck-boost chopper 311 rise. After the input voltage and output voltage of the buck-boost chopper 311 reach 320V, when a light load is applied, the input voltage of the buck-boost chopper 311 drops. When the input voltage of the buck-boost chopper 311 drops to 60V or less and the voltage of the capacitor unit 312 is 60V or less, the switch 318 turns on. That is, the switch 318 turns on when the input voltage of the buck-boost chopper 311 is 60V or less, the output voltage of the buck-boost chopper 311 is 320V or more, and the voltage of the capacitor unit 312 is 60V or less. As a result, power is supplied from the power receiving unit 310 to the capacitor unit 312 via the switch 318 (bypass circuit 314), and charging of the capacitor unit 312 starts.

[0049] When the capacitor unit 312 is fully charged and the voltage across the capacitor unit 312 is greater than 60V, the switch 318 is turned off.

[0050] 3, the driving device 32 drives and rotates a plurality of wheels (not shown). The driving device 32 is, for example, an electric motor or a linear motor, and uses power supplied from the power receiving device 31 as power for driving the driving device 32.

[0051] The transfer device 33 can hold and store the article to be transported, and transfers the article. The transfer device 33 is equipped with, for example, a side-pushing mechanism that holds and protrudes the article, and a lifting mechanism that moves the article downward, and delivers the article to a load port of a storage device such as a stocker or a load port of a processing device, which is the transfer destination, by driving the side-pushing mechanism and the lifting mechanism. The transfer device 33 uses power supplied from the power receiving device 31 as power for driving.

[0052] The control device 34 controls the driving device 32 and the transfer device 33. The control device 34 uses the power supplied from the power receiving device 31 as power for driving.

[0053] As described above, the ceiling transport vehicle 30 of the transport system 1 according to the present embodiment includes the power receiving device 31. In the power receiving device 31, the bypass circuit 314 supplies power from the power receiving unit 310 to the capacitor unit 312 via the bypass circuit 314 when the voltage of the capacitor unit 312 is equal to or lower than the first predetermined value. During initial charging of the capacitor unit 312, the voltage of the capacitor unit 312 is equal to or lower than the first predetermined value. In the power receiving device 31, power is supplied from the power receiving unit 310 to the capacitor unit 312 via the bypass circuit 314 during initial charging of the capacitor unit 312, thereby preventing an inrush current exceeding a certain current value (steady-state current value) from being generated from the power receiving unit 310 to the capacitor unit 312 during initial charging (when the power is turned on). In addition, unlike conventional devices, the power receiving device 31 does not need to adjust the current value of the inflow current, so heat generation during charging can be suppressed. Therefore, the power receiving device 31 can prevent an inrush current from being generated over a long charging time.

[0054] In the power receiving device 31 according to the present embodiment, the bypass circuit 314 includes a switch 318 for switching on / off the supply of power from the power receiving unit 310 to the capacitor unit 312 via the bypass circuit 314. The switch 318 is turned on when a predetermined condition is satisfied, and power is supplied from the power receiving unit 310 to the capacitor unit 312 via the bypass circuit 314. When the predetermined condition is not satisfied, the switch 318 is turned off, and the supply of power from the power receiving unit 310 to the capacitor unit 312 via the bypass circuit 314 is stopped. The switch 318 is turned on when the input voltage of the step-up / step-down chopper 311 is equal to or lower than a second predetermined value, the output voltage of the step-up / step-down chopper 311 is equal to or higher than a third predetermined value, and the voltage of the capacitor unit 312 is equal to or lower than a first predetermined value. With this configuration, it is possible to prevent a large voltage from being applied to the bypass circuit 314. In addition, the capacitor unit 312 can be charged after power is supplied to the step-up / step-down chopper 311. Furthermore, when the voltage of capacitor unit 312 is equal to or lower than the first predetermined value, power can be reliably supplied from power receiving unit 310 to capacitor unit 312.

[0055] In the power receiving device 31 according to the present embodiment, the bypass circuit 314 includes a first comparator CP1, a second comparator CP2, and a third comparator CP3. This configuration can increase the operating voltage and reduce the influence of noise.

[0056] Although the embodiment of the present invention has been described above, the present invention is not necessarily limited to the above-described embodiment, and various modifications are possible without departing from the gist of the present invention.

[0057] In the above embodiment, the track rail T is an orbital track, but the track rail T is not limited to this.

[0058] In the above embodiment, the bypass unit is the bypass circuit 314. However, the bypass unit may be a computer system or a processor implemented in an integrated circuit. This configuration can reduce the size of the device.

[0059] In the above embodiment, an example has been described in which the auxiliary power supply is the capacitor unit 312. However, the auxiliary power supply may be, for example, a secondary battery such as a lithium ion battery.

[0060] In the above embodiment, the switch 318 is turned on when the following predetermined conditions are satisfied: (1) the input voltage of the buck-boost chopper 311 is 60 V or less, (2) the output voltage of the buck-boost chopper 311 is 320 V or more, and (3) the voltage of the capacitor unit 312 is 60 V or less. However, the switch 318 may be turned on when at least the condition (1) is satisfied.

[0061] In the above embodiment, a description has been given of an example in which the contactless power supply system is applied to the transportation system 1. However, the contactless power supply system may be applied to other systems. [Explanation of symbols]

[0062] 1...transport system (non-contact power supply system), 10...non-contact power supply device (power transmission device), 21A, 21B...power supply line, 30...ceiling transport vehicle (traveling vehicle), 31...power receiving device, 310...power receiving unit (power receiving section), 311...step-up / step-down chopper, 312...capacitor unit (auxiliary power source), 314...bypass circuit (bypass section), 318...switch (switching section), T...track rail.

Claims

1. a power receiving unit that receives power in a non-contact manner from a power source that supplies power with a constant current value; a step-up / step-down chopper connected to the power receiving unit, which controls the power supplied from the power receiving unit and supplies the power to a load; an auxiliary power supply connected to the buck-boost chopper and supplying the power to the load via the buck-boost chopper; a bypass unit that supplies the electric power from the power receiving unit to the auxiliary power supply by bypassing the step-up / step-down chopper, the bypass unit includes a switching unit that switches on / off the supply of the power from the power receiving unit to the auxiliary power supply via the bypass unit, the switching unit is turned on when a predetermined condition is satisfied, and causes the power to be supplied from the power receiving unit to the auxiliary power supply via the bypass unit, and is turned off when the predetermined condition is not satisfied, and causes the supply of the power from the power receiving unit to the auxiliary power supply via the bypass unit to be stopped; the predetermined condition includes a case where a voltage of the auxiliary power supply is equal to or lower than a first predetermined value, The power receiving device, wherein the power is supplied from the power receiving unit to the load via the step-up / step-down chopper regardless of whether the switching unit is in an on or off state.

2. the predetermined condition includes a case where an input voltage of the buck-boost chopper is equal to or lower than a second predetermined value, The power receiving device according to claim 1 , wherein the switching unit is turned on when the voltage of the auxiliary power supply is equal to or lower than the first predetermined value and the input voltage of the buck-boost chopper is equal to or lower than the second predetermined value.

3. the predetermined condition includes a case where an output voltage of the buck-boost chopper is equal to or higher than a third predetermined value, 3. The power receiving device according to claim 2, wherein the switching unit is turned on when the voltage of the auxiliary power supply is equal to or lower than the first predetermined value, the input voltage of the buck-boost chopper is equal to or lower than the second predetermined value, and the output voltage of the buck-boost chopper is equal to or higher than the third predetermined value.

4. 4. The power receiving device according to claim 1, wherein the bypass unit is a circuit including a comparator.

5. A power receiving device according to any one of claims 1 to 4, A contactless power supply system comprising: a power transmitting device that transmits power having a constant current value to the power receiving device.

6. the power transmission device has a power supply line provided along a track rail, The contactless power supply system according to claim 5 , wherein the power receiving device is provided in a traveling vehicle that travels on the track rail.

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