Non-contact power supply system and computer program

Abstract

To restrain the output power of an AC power supply device from exceeding the rated output power in a non-contact power supply system.SOLUTION: Non-contact power supply systems 1000, 1000A, 1000B, 1000C, and 1000D comprise: AC power supply devices 110 and 110C; multiple power transmission devices 120, 120A, and 120B which are connected in parallel with each other with respect to the AC power supply device; power reception devices 200 and 200C for receiving power in a non-contact manner from the power transmission device; and a power supply voltage control unit 140 for controlling the output voltage of the AC power supply device. The power supply voltage control unit performs a primary-side power suppression control so as to lower the output voltage below an allowable output power when the output power of the AC power supply device exceeds the rated output power.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a contactless power supply system, a computer program, a power transmitting device, and a power receiving device. [Background technology]

[0002] There is known a power supply system that transmits electric power from a power transmitting device and supplies the power to a vehicle equipped with a power receiving device. The power supply system described in Patent Document 1 enables transmission of large power by configuring a power transmitting device by connecting multiple power transmitting resonant circuits in parallel to one power source. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2022 / 004034 Summary of the Invention [Problem to be solved by the invention]

[0004] However, as the number of power receiving devices receiving power from the power supply system increases, the supplied power may exceed the rated output power of the power source, causing a risk of power transmission to all of the power receiving devices being stopped. [Means for solving the problem]

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

[0006] According to one embodiment of the present disclosure, there is provided a contactless power supply system (1000, 1000A, 1000B, 1000C, 1000D). The contactless power supply system includes an AC power supply device (110, 110C) that supplies AC power at a predetermined operating frequency, and a plurality of power transmission devices (120, 120A, 120B) that are connected in parallel to the AC power supply device, the plurality of power transmission devices having a primary-side resonant circuit (10, 10A) having a primary-side coil (Ls) and a primary-side capacitor (Cs), and a power receiving device (200, 200C) that receives power from the power transmission device in a contactless manner. The power receiving device includes a secondary side resonant circuit having a secondary side coil (Lr) and a secondary side capacitor (Cr) for magnetically coupling with the primary side coil, a rectifier circuit (230) for rectifying AC power output from the secondary side resonant circuit and converting it into DC power, a power receiving side control unit (220) for controlling the rectifier circuit, and a load device (210) to which the DC power is supplied at a constant current, and a power supply voltage control unit (140) for controlling the output voltage of the AC power supply device, wherein the power supply voltage control unit performs primary side power suppression control for reducing the output voltage so that it falls below a preset allowable output power when the output power of the AC power supply device exceeds the rated output power of the AC power supply device.

[0007] According to this form of control device, when the output power of the AC power supply device exceeds the rated output power of the AC power supply device, the output voltage is reduced to below a preset allowable output power. This makes it possible to prevent the output power of the AC power supply device from becoming excessive, which would cause the AC power supply device to stop operating and stop transmitting power to all power receiving devices. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram showing a schematic configuration of a contactless power supply system according to a first embodiment. [Diagram 2] FIG. 2 is an explanatory diagram showing a circuit configuration of the contactless power supply system according to the first embodiment. [Diagram 3] 4 is a flowchart showing a procedure of primary side power limiting control in the first embodiment. [Figure 4]FIG. 11 is an explanatory diagram showing a circuit configuration of a contactless power supply system according to a second embodiment. [Diagram 5] 10 is a flowchart showing a procedure of power transmission state switching control in the second embodiment. [Figure 6] FIG. 11 is an explanatory diagram showing a circuit configuration of a contactless power supply system according to a third embodiment. [Figure 7] 13 is a flowchart showing a procedure of power transmission state switching control in the third embodiment. [Figure 8] 13 is a flowchart showing a procedure of secondary-side power limiting control in the fourth embodiment. [Figure 9] FIG. 13 is an explanatory diagram showing a circuit configuration of a contactless power supply system according to another embodiment. [Figure 10] FIG. 13 is an explanatory diagram showing a circuit configuration of a contactless power supply system according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A. First embodiment: A-1. System configuration: A contactless power supply system 1000 of this embodiment shown in Fig. 1 includes a power transmission system 100 and a power receiving device 200. In this embodiment, the power transmission system 100 is buried under a road 105. The power receiving device 200 is mounted on an electric vehicle 202 as a mobile body that travels on the road 105. In this embodiment, the electric vehicle 202 is configured as an AGV (Automatic Guided Vehicle) that travels in a factory or warehouse.

[0010] In the contactless power supply system 1000, the power transmission system 100 supplies power to the power receiving device 200 when the electric vehicle 202 travels on the track 105. "Traveling on the track 105" includes cases where the electric vehicle 202 is moving, as well as cases where the electric vehicle 202 is stopped near fixed equipment such as a transport robot or a conveyor for transferring transported goods, etc. In Fig. 1, the x-axis direction indicates the traveling direction of the electric vehicle 202, the y-axis direction indicates the width direction of the electric vehicle 202, and the z-axis direction indicates the vertical upward direction.

[0011] The power transmission system 100 includes an AC power supply device 110, a plurality of power transmission devices 120, and a control device 130. The AC power supply device 110 supplies AC power at a predetermined operating frequency. A specific configuration of the AC power supply device 110 will be described later.

[0012] The multiple power transmission devices 120 are installed underground along the x-axis direction of the track 105. The power transmission devices 120 may be installed at a location other than underground of the track 105, for example, on the side of the transportation facility. The power transmission devices 120 are connected in parallel to the AC power supply device 110 and are supplied with AC power from the AC power supply device 110. Each power transmission device 120 has a primary side resonant circuit 10. The primary side resonant circuit 10 is supplied with AC power from the AC power supply device 110 and transmits the AC power in a non-contact manner to a secondary side resonant circuit 240 described later. A specific configuration of the primary side resonant circuit 10 will be described later.

[0013] The control device 130 is configured as a computer having a CPU 131, a memory 132, and a communication device 133. The CPU 131 functions as a power supply voltage control unit 140 by executing a program stored in the memory 132 in advance.

[0014] The power supply voltage control unit 140 controls the output voltage of the AC power supply device 110. More specifically, when the output power of the AC power supply device 110 does not exceed the rated output power, the power supply voltage control unit 140 controls the AC power supply device 110 to output a preset constant voltage (hereinafter also referred to as a "prescribed voltage"). In this embodiment, the prescribed voltage is set as a voltage at which the output power does not exceed the rated output power when two power transmission devices 120 simultaneously supply power to the power receiving device 200 in the power transmission system 100.

[0015] On the other hand, when the output power of the AC power supply device 110 exceeds the rated output power, the power supply voltage control unit 140 performs primary side power suppression control to reduce the output voltage of the AC power supply device 110 so that the output power falls below the allowable output power. The "allowable output power" means a power that is set in advance as a power that the AC power supply device 110 can continue to supply power. The allowable output power may be set to a power equal to or less than the rated output power, and may be set to a power greater than the rated output power of the AC power supply device 110, for example, a power greater than the rated output power by several kW, so long as the power is large enough that the AC power supply device 110 does not immediately stop operating. The voltage output in the primary side power suppression control is also referred to as a "suppression voltage" in the following description. In this embodiment, the suppression voltage is determined so that the output power during the execution of the primary side power suppression control is equivalent to the output power when two power transmitting devices 120 simultaneously supply power to the power receiving device 200 by a preset voltage. The procedure of the primary side power suppression control will be described later. The suppression voltage may be determined so that the output power during execution of the primary side power suppression control is lower than the output power when two power transmitting devices 120 simultaneously supply power to the power receiving device 200 with a preset voltage.

[0016] The power receiving device 200 includes a battery 210, an auxiliary battery 215, a power receiving side control unit 220, a rectifier circuit 230, a secondary side resonant circuit 240, a DC / DC converter circuit 260, an inverter circuit 270, a motor generator 280, and an auxiliary 290. The power receiving device 200 does not need to include the auxiliary 290, and in this case, the auxiliary battery 215 and the DC / DC converter circuit 260 are also not required. In this embodiment, the secondary side resonant circuit 240 is provided at a position facing the road 105, for example, on the underside of the electric vehicle 202. When the power transmitting device 120 is disposed on the side of the fixed equipment, the secondary side resonant circuit 240 may be provided on the side of the electric vehicle 202. A specific configuration of the secondary side resonant circuit 240 will be described later.

[0017] The secondary resonant circuit 240 is connected to the rectifier circuit 230, and the AC power received by the secondary resonant circuit 240 is converted to DC power by the rectifier circuit 230. The battery 210, the high-voltage side of the DC / DC converter circuit 260, and the inverter circuit 270 are connected to the output of the rectifier circuit 230. The auxiliary battery 215 and the auxiliary 290 are connected to the low-voltage side of the DC / DC converter circuit 260. The motor generator 280 is connected to the inverter circuit 270. The DC power output from the rectifier circuit 230 can be used to charge the battery 210 and drive the motor generator 280 via the inverter circuit 270. In addition, the DC power output from the rectifier circuit 230 can also be used to charge the auxiliary battery 215 and drive the auxiliary 290 by lowering the voltage using the DC / DC converter circuit 260.

[0018] The battery 210 is a secondary battery that outputs a relatively high DC power for driving the motor generator 280, for example, a voltage of several tens to several hundreds of volts. The motor generator 280 operates as a three-phase AC motor and generates a driving force for running the electric vehicle 202. The motor generator 280 operates as a generator when the electric vehicle 202 decelerates and regenerates electric power. When the motor generator 280 operates as a motor, the inverter circuit 270 converts the electric power of the battery 210 into three-phase AC and supplies it to the motor generator 280. When the motor generator 280 operates as a generator, the inverter circuit 270 converts the three-phase AC regenerated by the motor generator 280 into DC and supplies it to the battery 210. The battery 210 corresponds to the "load device" in this disclosure.

[0019] The DC / DC converter circuit 260 converts the output of the battery 210 to a voltage lower than the output voltage of the battery 210, for example, 12 V, and supplies the voltage to the auxiliary battery 215 and the auxiliary device 290. The auxiliary battery 215 is a secondary battery for driving the auxiliary device 290, and has a relatively low voltage. The auxiliary device 290 includes an air conditioner, an electric power steering device, peripheral devices such as headlights, blinkers, and wipers of the electric vehicle 202, and various accessories of the electric vehicle 202.

[0020] The power receiving side control unit 220 controls each unit, including the inverter circuit 270, in the electric vehicle 202. When receiving contactless power supply while traveling, the power receiving side control unit 220 controls the secondary side resonant circuit 240 to receive power.

[0021] A-2.Circuit configuration: As shown in FIG. 2, the AC power supply device 110 includes a DC power supply PS, an inverter circuit INV, a filter circuit F11, and a current sensor S1. The DC power supply PS supplies DC power to the inverter circuit INV. The inverter circuit INV includes four switching elements Q11-Q14 that configure a bridge circuit. In this embodiment, the switching elements Q1-Q4 are realized by MOSFETs (metal-oxide-semiconductor field-effect transistors). The inverter circuit INV converts DC power supplied from the DC power supply PS into AC power of a preset operating frequency and a voltage commanded by the power supply voltage control unit 140 by controlling the switching elements Q1-Q4 by the control device 130 to change the duty ratio and the phase shift amount.

[0022] The filter circuit F11 suppresses passage of noise components of the AC power input from the inverter circuit INV and passes AC power of a target frequency band, and supplies a constant amount of current to the power transmitting device 120. The filter circuit F11 of this embodiment is configured as a bandpass filter in which a coil L11 and a capacitor C11 are connected in series.

[0023] The current sensor S1 detects a current (hereinafter also referred to as an “output current”) that passes through the filter circuit F11 and is output from the AC power supply device 110. The current sensor S1 also transmits the detected output current to the control device .

[0024] The power transmitting device 120 has a primary side resonant circuit 10 in which a primary side capacitor Cs and a primary side coil Ls are connected in series. In this embodiment, while AC power is being supplied from the AC power supply device 110 to the power transmitting device 120, the primary side resonant circuit 10 is in a resonant state at an operating frequency and in a power transmitting state in which power can be supplied to the power receiving device 200. When the primary side resonant circuit 10 is in a power transmitting state, if the power receiving device 200 enters an area (hereinafter also referred to as a "power transmitting area") predetermined for each power transmitting device 120, the primary side resonant circuit 10 starts transmitting power to the power receiving device 200.

[0025] The power receiving device 200 includes a filter circuit F21 in addition to the configuration shown in Fig. 1. As shown in Fig. 2, the filter circuit F21 is connected between the secondary side resonant circuit 240 and the rectifier circuit 230. The secondary side resonant circuit 240 is formed by connecting a secondary side coil Lr and a secondary side capacitor Cr in series. In this embodiment, the filter circuit F21 is configured as a bandpass filter in which a coil L21 and a capacitor C21 are connected in series. The filter circuit F21 suppresses the passage of noise components of the AC power input from the secondary side resonant circuit 240, passes AC power of a target frequency band, and supplies a constant amount of current to the rectifier circuit 230.

[0026] In this embodiment, the rectifier circuit 230 is composed of four switching elements Q21-Q24 that configure a bridge circuit, and a smoothing capacitor C22. In this embodiment, the switching elements Q21-Q24 are realized by MOSFETs. The rectifier circuit 230 converts the AC power input from the filter circuit F21 into DC power and supplies it to the battery 210 by controlling the on / off state of the switching elements Q21-Q24 by the power receiving side control unit 220. In the following description, the magnitude of the DC power supplied to the battery 210 is also referred to as "secondary side power." The magnitude of the current supplied to the battery 210 is controlled to be constant by the filter circuit F21 and the rectifier circuit 230.

[0027] A-3. Primary side power suppression control: 3, the power supply voltage control unit 140 controls the output voltage of the AC power supply device 110 so that the output power of the AC power supply device 110 does not exceed the allowable output power. The primary side power limiting control is started when the power transmission system 100 is started, and is repeatedly executed while the power transmission system 100 is in operation.

[0028] In step S110, the power supply voltage control unit 140 acquires from the current sensor S1 the output current detected by the current sensor S1 and calculates the output power of the AC power supply device 110. As described above, the output voltage of the AC power supply device 110 is controlled to be the voltage commanded by the power supply voltage control unit 140, so the power supply voltage control unit 140 can calculate the output power of the AC power supply device 110 by using the output current acquired from the current sensor S1 and the voltage commanded to the AC power supply device 110 by the power supply voltage control unit 140 itself.

[0029] In step S120, the power supply voltage control unit 140 determines whether the output power exceeds the rated output power. If it is determined that the output power exceeds the rated output power (step S120: Yes), the power supply voltage control unit 140 controls the AC power supply device 110 to output the suppression voltage described above (step S130). If the state in which the output power is excessively large compared to the rated output power continues, the AC power supply device 110 may stop operating, and power transmission to all of the power receiving devices 200 may stop. To avoid such a situation, the power supply voltage control unit 140 controls the AC power supply device 110 to output a suppression voltage that is below the above-mentioned allowable output power.

[0030] On the other hand, if it is determined that the output power does not exceed the rated output power (step S120: No), power supply voltage control unit 140 controls AC power supply device 110 to output the above-mentioned specified voltage (step S135).

[0031] According to the embodiment of the wireless power supply system 1000 described above, when the output power of the AC power supply device 110 exceeds the rated output power, the output voltage is reduced to be below the allowable output power. This makes it possible to prevent the output power of the AC power supply device 110 from becoming excessive, which would cause the operation of the AC power supply device 110 to stop, thereby preventing the transmission of power to all of the power receiving devices 200 from stopping.

[0032] B. Second embodiment: As shown in Fig. 4, the contactless power supply system 1000A of the second embodiment is different from the contactless power supply system 1000 of the first embodiment in that the contactless power supply system 1000A includes a power transmission device 120A instead of the power transmission device 120. The contactless power supply system 1000A of the second embodiment is also different from the contactless power supply system 1000 of the first embodiment in that the contactless power supply system 1000A of the second embodiment executes the power transmission state switching control shown in Fig. 5. Note that the system configuration of the contactless power supply system 1000A of the second embodiment and other steps in the primary side power suppression control are the same as those of the contactless power supply system 1000 of the first embodiment, so the same configurations and steps are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0033] B-1.Circuit configuration: The power transmission system 100A differs from the power transmission system 100 of the first embodiment in that a power transmission device 120A is provided instead of the power transmission device 120. The power transmission device 120A has an impedance variable element 20 instead of the primary side capacitor Cs, and the primary side coil Ls and the impedance variable element 20 form a primary side resonant circuit 10A. The power transmission device 120A further includes a primary side detection circuit 30 and a primary side control circuit 40.

[0034] The variable impedance element 20 is connected between the AC power supply device 110 and the primary coil Ls. The variable impedance element 20 includes two capacitors 12, a capacitor 13, and a switch SW. The capacitor 12 and the primary coil Ls are connected in series. The capacitor 13 and the switch SW are connected in series, and the capacitor 13 and the switch SW connected in series are connected in parallel with the capacitor 12. The switch SW may be a mechanical contact such as a relay that switches in response to an external command, but may also be configured to use a semiconductor element such as a MOS-FET or an analog switch.

[0035] The impedance variable element 20 changes its capacitance by switching the switch SW on and off. When the switch SW is on, the capacitor 13 is connected to the primary coil Ls. At this time, the capacitance of the impedance variable element 20 is equal to the sum of the capacitance of the capacitor 12 and the capacitance of the capacitor 13. When the switch SW is off, the capacitor 13 is disconnected from the primary coil Ls. At this time, the capacitance of the impedance variable element 20 is equal to the capacitance of the capacitor 12. By changing the capacitance of the impedance variable element 20 in this way, the impedance of the primary resonant circuit 10A when the switch SW is on is lower than when the switch SW is off. With this change in impedance of the primary resonant circuit 10A, the resonant state of the primary resonant circuit 10A also changes. In this embodiment, when the switch SW is on, the primary resonant circuit 10A is in a resonant state at the operating frequency and in a power transmission state. When the switch SW is off, the primary resonant circuit 10A is in a non-resonant state at the operating frequency and in a standby state. In the standby state, the power transmitting device 120A causes a standby current smaller than the current flowing in the power transmitting state to flow through the primary coil Ls, and waits until the power transmitting state is entered.

[0036] The primary side detection circuit 30 is configured as a sensor that detects the magnitude of the magnetic flux interlinked with the primary side coil. In this embodiment, the primary side detection circuit 30 detects the voltage across the primary side coil Ls and detects the magnitude of the magnetic flux using the change in the voltage. The primary side detection circuit 30 outputs a signal indicating the magnitude of the detected magnetic flux to the primary side control circuit 40.

[0037] The primary side control circuit 40 drives the switch SW to switch the switch SW on and off using the signal output from the primary side detection circuit 30. Specific processing in the primary side control circuit 40 will be described in the power transmission state switching control described later.

[0038] B-2. Power transmission state switching control: 5 according to the degree of magnetic coupling between the power transmitting device 120A and the power receiving device 200, and controls the power transmitting state of the power transmitting device 120A. The power transmitting state switching control is started when the power transmitting system 100A is started, and is repeatedly executed in parallel for each power transmitting device 120A while the power transmitting system 100A is started.

[0039] In step S210, the primary side control circuit 40 judges whether or not the magnitude of the magnetic flux indicated by the signal output from the primary side detection circuit 30 is equal to or greater than a preset threshold value. The magnitude of the magnetic flux changes according to the degree of magnetic coupling between the power transmitting device 120A and the power receiving device 200, and increases as the power transmitting device 120A and the power receiving device 200 approach each other. The threshold value of the magnitude of the magnetic flux is specified and set in advance by performing a simulation or the like as a value when the power receiving device 200 enters the power transmitting area of ​​the power transmitting device 120A. The primary side control circuit 40 repeatedly performs this judgment while it is judged that the magnitude of the magnetic flux is less than the threshold value (step S210: No).

[0040] If it is determined that the magnitude of the magnetic flux is equal to or greater than the threshold value (step S210: Yes), the primary side control circuit 40 switches the switch SW on to switch the primary side resonant circuit 10A to a power transmission state, and the power transmitting device 120A starts transmitting power (step S220).

[0041] In step S230, the primary side control circuit 40 determines whether or not the magnitude of the magnetic flux indicated by the signal output from the primary side detection circuit 30 is less than a preset threshold value. While it is determined that the magnitude of the magnetic flux is equal to or greater than the threshold value (step S230: No), the primary side control circuit 40 repeatedly performs such determination, and the power transmitting device 120A continues power transmission.

[0042] If it is determined that the magnitude of the magnetic flux is equal to or greater than the threshold (step S230: Yes), the primary side control circuit 40 switches the switch SW to OFF to switch the primary side resonant circuit 10A to a standby state, and the power transmitting device 120A stops transmitting power (step S240). After that, the primary side control circuit 40 executes step S210 again.

[0043] According to the contactless power supply system 1000A of the second embodiment described above, when the primary side detection circuit 30 detects a decrease in magnetic flux, the state is shifted from the power transmission state to the standby state to suppress the current. This makes it possible to further suppress the output power of the AC power supply device 110 from becoming excessive, which would cause the operation of the AC power supply device 110 to stop.

[0044] C. Third embodiment: The contactless power supply system 1000B of the third embodiment differs from the contactless power supply system 1000A of the second embodiment in that it further includes a voltage detection circuit 50, as shown in Fig. 6. Also, the contactless power supply system 1000B of the third embodiment differs from the contactless power supply system 1000A of the second embodiment in that step S215 is executed after step S210 in the power transmission state switching control, as shown in Fig. 7. Note that the system configuration of the contactless power supply system 1000B of the third embodiment and other procedures in the primary side power suppression control and the power transmission state switching control are the same as those of the contactless power supply system 1000A of the second embodiment, so the same configurations and procedures are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

[0045] 6, the power transmitting device 120B differs from the power transmitting device 120A of the second embodiment in that it includes a voltage detection circuit 50 in addition to the configuration of the power transmitting device 120A described above. The voltage detection circuit 50 detects a supply voltage to the power transmitting device 120B between the impedance variable element 20 and the AC power supply device 110. The power transmitting device 120B outputs a signal indicating the detected supply voltage to the primary side detection circuit 30.

[0046] 7, in the power transmission state switching control, after step S210, the primary side control circuit 40 determines whether or not the supply voltage indicated by the signal output from the voltage detection circuit 50 is equal to or greater than a preset threshold (step S215). The supply voltage threshold is set to a value equivalent to the above-mentioned predetermined voltage. Here, the case where the supply voltage is not equal to or greater than the threshold corresponds to the case where the above-mentioned primary side power suppression control is being executed and the supply voltage is below the predetermined voltage.

[0047] If the supply voltage is equal to or higher than the threshold (step S215: Yes), steps S220 to S240 are executed as in the second embodiment described above, and then the primary side control circuit 40 executes step S210 again. On the other hand, if the supply voltage is lower than the threshold (step S215: No), steps S220 to S240 are not executed, and the primary side control circuit 40 executes step S210 again. Thus, in the power transmission state switching control of this embodiment, when the supply voltage is lower than the threshold, in other words, when the above-mentioned primary side power suppression control is being executed, even if the power receiving device 200 enters the power transmission area of ​​the power transmitting device 120B and the magnitude of the magnetic flux becomes equal to or higher than the threshold, the primary side control circuit 40 does not shift the state of the power transmitting device 120B from the standby state to the power transmitting state.

[0048] According to the contactless power supply system 1000B of the third embodiment described above, when the primary side power limiting control is being performed, the state of the power transmitting device 120B is not shifted from the standby state to the power transmitting state even if an increase in magnetic flux is detected. This makes it possible to prevent a situation in which power supply to a new power receiving device 200 is started during the execution of the primary side power limiting control, causing the output power of the AC power supply device 110 to become excessive, causing the operation of the AC power supply device 110 to stop, and causing power transmission to all of the power receiving devices 200 to stop.

[0049] D. Fourth embodiment: The non-contact power supply system 1000B of the fourth embodiment differs from the non-contact power supply system 1000B of the third embodiment in that the power supply voltage control unit 140 transmits a notification to the power receiving device 200 and the power receiving side control unit 220 executes the secondary side power limiting control shown in Fig. 8. In this embodiment, the power supply voltage control unit 140 and the power receiving device 200 are configured to be able to communicate with each other. Note that the system configuration of the non-contact power supply system 1000B of the fourth embodiment and other procedures in the primary side power limiting control and the power transmission state switching control are the same as those of the non-contact power supply system 1000B of the third embodiment, so the same configurations and procedures are denoted by the same reference numerals and detailed description thereof will be omitted.

[0050] The power supply voltage control unit 140 of this embodiment transmits to the power receiving device 200 a control state signal indicating whether or not the primary side power restriction control is being executed, and a notification including information indicating the suppression rate in the secondary side power restriction control. The "suppression rate" means a ratio indicating the degree of suppression of the secondary side power by the secondary side power restriction control. More specifically, the suppression rate means a ratio of the secondary side power after the secondary side power restriction control is executed to the secondary side power before the secondary side power restriction control is executed. In this embodiment, the suppression rate is calculated by the AC power supply device 110 by dividing the rated output power of the AC power supply device 110 by a value obtained by multiplying the number of the power receiving devices 200 currently executing power supply by the rated power consumption of the power receiving device 200, which is determined in advance. The power supply voltage control unit 140 can specify the number of the power receiving devices 200 currently executing power supply by using the output current detected by the current sensor S1. This is because the output current increases in proportion to the number of the power receiving devices 200 currently executing power supply.

[0051] When the power receiving device 200 receives the notification from the power supply voltage control unit 140, it executes the secondary-side power restriction control shown in Fig. 8. In step S310, the power receiving side control unit 220 determines whether or not the control state signal included in the received notification indicates that the primary-side power restriction control is being executed. If it is determined that the control state signal indicates that the primary-side power restriction control is not being executed (step S310: No), the power receiving device 200 executes normal power supply (step S334) and ends the secondary-side power restriction control.

[0052] If it is determined that the primary-side power limiting control is being executed (step S310: Yes), the power receiving-side control unit 220 determines whether or not power supply is being executed in the secondary-side resonant circuit 240 (step S320). This determination can be made, for example, by detecting the voltage across the secondary-side coil Lr by a voltage sensor (not shown) and utilizing a change in the voltage.

[0053] If power supply is being performed (step S320: Yes), the power receiving side control unit 220 controls the rectifier circuit 230 to supply the secondary side power suppressed according to the above-mentioned suppression rate to the battery 210 (step S330). More specifically, the power receiving side control unit 220 adjusts the period of a commutation mode in which the switching element Q22 and the switching element Q24 are simultaneously turned on in the rectifier circuit 230, thereby supplying the suppressed secondary side power to the battery 210. Thereafter, the power receiving device 200 ends the secondary side power suppression control.

[0054] If power feeding is not being performed (step S320: No), the power receiving side control unit 220 prohibits the electric vehicle 202 from entering the power transmission area (step S332). More specifically, the power receiving side control unit 220 controls the electric vehicle 202, for example, to travel by detouring the power transmission area via an ECU (not shown) that is mounted on the electric vehicle 202 and controls the traveling of the electric vehicle 202. By controlling the electric vehicle 202 in this manner, it is possible to prohibit the power receiving device 200 from newly starting power feeding. Thereafter, the power receiving device 200 ends the secondary side power suppression control.

[0055] According to the contactless power supply system 1000B of the fourth embodiment described above, when a notification indicating that the primary-side power limiting control is being executed is received and power supply is not being executed in the secondary-side resonant circuit 240, the power receiving device 200 is prohibited from starting new power supply. This makes it possible to prevent a situation in which power supply to a new power receiving device 200 starts while the primary-side power limiting control is being executed, causing the output power of the AC power supply device 110 to become excessive, causing the operation of the AC power supply device 110 to stop, and causing power transmission to all of the power receiving devices 200 to stop.

[0056] Furthermore, when the contactless power supply system 1000B of the present embodiment receives a notification indicating that the primary-side power suppression control is being executed and power supply is being executed in the secondary-side resonant circuit 240, the contactless power supply system 1000B executes power supply by suppressing the secondary-side power according to a determined suppression rate. This suppresses the current flowing through the power transmission device 120B that is transmitting power to the power receiving device 200, so that it is possible to suppress a situation in which the output power of the AC power supply device 110 becomes excessive, causing the operation of the AC power supply device 110 to stop, and power transmission to all of the power receiving devices 200 to stop.

[0057] Moreover, since the AC power supply device 110 sets the suppression rate as a value obtained by dividing the rated output power of the AC power supply device 110 by a value obtained by multiplying the predetermined rated power consumption of the power receiving device 200 by the number of the power receiving devices 200 currently performing power supply, the AC power supply device 110 can output power close to the rated output power. This makes it possible to suppress a decrease in the power supply efficiency to the power receiving device 200 caused by excessive suppression of the output power of the AC power supply device 110.

[0058] E. Fifth embodiment: The contactless power supply system 1000B of the fifth embodiment differs from the contactless power supply system 1000B of the fourth embodiment in the method of calculating the suppression rate. Note that the system configuration of the contactless power supply system 1000B of the fifth embodiment and other procedures in the primary side power suppression control, the power transmission state switching control, and the secondary side power suppression control are the same as those of the contactless power supply system 1000B of the fourth embodiment, so the same configurations and procedures are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

[0059] In this embodiment, the suppression rate is calculated by the AC power supply device 110 by dividing the rated output voltage of the AC power supply device 110 by the current output voltage of the AC power supply device 110. The current output voltage of the AC power supply device 110 changes with the change in the coupling coefficient between the primary coil Ls and the secondary coil Lr due to the positional relationship between the power transmission device 120B and the power receiving device 200, even if the number of the power receiving devices 200 that are supplying power to the power transmission system 100B does not change. More specifically, when the power transmission device 120 and the power receiving device 200 are separated from each other, the coupling coefficient becomes low, and power supply is performed with a secondary power lower than the rated power consumption of the power receiving device 200. In such a case, if the secondary power of the power receiving device 200 is suppressed according to the suppression rate determined using the rated power consumption of the power receiving device 200, the secondary power is excessively suppressed and falls far below the rated output power of the AC power supply device 110, and the power supply efficiency to the power receiving device 200 may decrease. According to the method for calculating the suppression rate of the present embodiment, the suppression rate is calculated using the current output voltage that reflects the degree of the coupling coefficient that changes depending on the positional relationship between each power transmitting device 120B and each power receiving device 200, so that such a problem can be avoided.

[0060] According to the contactless power supply system 1000B of the fifth embodiment described above, the suppression rate is set as a value obtained by dividing the rated output voltage of the AC power supply device 110 by the current output voltage of the AC power supply device 110, so that the AC power supply device 110 can output power close to the rated output power according to the current output power. This makes it possible to further suppress a decrease in the power supply efficiency to the power receiving device 200 caused by excessive suppression of the output power of the AC power supply device 110.

[0061] F. Other Embodiments: (F1) In each of the above-mentioned embodiments, the AC power supply device 110 has the filter circuit F11, and the power receiving device 200 has the filter circuit F21, but the present disclosure is not limited thereto. As in the non-contact power supply system 1000C shown in FIG. 9, the non-contact power supply system may be configured to include an AC power supply device 110C having a filter circuit F12 instead of the filter circuit F11, and a power receiving device 200C having a filter circuit F22 instead of the filter circuit F21. The filter circuit F12 is configured as an immittance filter in which the coil L111 and the coil L112 are connected in series, and the capacitor C111 is connected in parallel between the coil L111 and the coil L112. The filter circuit F22 is configured as an immittance filter in which the coil L121 and the coil L122 are connected in series, and the capacitor C121 is connected in parallel between the coil L121 and the coil L122. The non-contact power supply system 1000C in this form also provides the same effects as the above-mentioned embodiments.

[0062] Also, as shown in FIG. 10, the contactless power supply system may be configured to include the AC power supply device 110 of the first embodiment having the filter circuit F11 configured as a bandpass filter, the above-mentioned power receiving device 200C having the immittance filter F22, and a tertiary resonant circuit 300. The tertiary resonant circuit 300 is configured as a closed circuit in which the tertiary coil L311 and the tertiary capacitor C311 are connected in series. The tertiary resonant circuit 300 is arranged so that the tertiary coil L311 is magnetically coupled to the primary coil Ls of the primary resonant circuit 10 and the secondary coil Lr of the secondary resonant circuit 240. The contactless power supply system 1000D of this form also provides the same effects as the above-mentioned embodiment.

[0063] (F2) In each of the above embodiments, the AC power supply device 110 has a filter circuit F11, and the power receiving device 200 has a filter circuit F21, but the present disclosure is not limited to this. When the power supplied by the contactless power supply system 1000 is small, both the AC power supply device 110 and the power receiving device 200 do not need to have a filter circuit. The contactless power supply system 1000 of this form also provides the same effects as the above embodiments.

[0064] (F3) In the second embodiment, the primary control circuit 40 is configured as a sensor that detects the magnitude of the magnetic flux interlinked with the primary coil by utilizing the change in the voltage across the primary coil Ls, but the present disclosure is not limited to this. For example, the primary control circuit 40 may detect the magnitude of the magnetic flux near the primary coil by utilizing the change in the current flowing through a detection coil disposed near the primary coil Ls. The contactless power supply system 1000A of this configuration also provides the same effects as the second embodiment.

[0065] (F4) In the above third embodiment, the primary side detection circuit 30 determines whether or not the primary side power limiting control is being executed by detecting the voltage supplied to the power transmitting device 120B using the voltage detection circuit 50, but the present disclosure is not limited to this. The primary side detection circuit 30 may receive a control state signal indicating whether or not the primary side power limiting control is being executed from the power supply voltage control unit 140, and use the control state signal to determine whether or not the primary side power limiting control is being executed. According to the contactless power supply system 1000B of this embodiment, the voltage detection circuit 50 is not required, so that the system configuration of the contactless power supply system 1000B can be prevented from becoming complicated.

[0066] (F5) In the above fourth embodiment, the power supply voltage control unit 140 transmits a notification directly to the power receiving side control unit 220, but the present disclosure is not limited to this. In a configuration further including a running system that controls a plurality of power receiving devices 200, the power supply voltage control unit 140 may transmit a notification to the power receiving side control unit 220 via the running system. The contactless power supply system 1000B of this form also achieves the same effects as the above embodiments.

[0067] (F6) In the above fourth embodiment, when the primary-side power suppression control is being executed and the power receiving device 200 is not feeding power, the power receiving side control unit 220 prohibits the power receiving device 200 from starting new power feeding, but the present disclosure is not limited thereto. In such a case, control may be performed to suppress the speed at which the power receiving device 200 enters the power transmission area. By performing such control, it is possible to lengthen the time from when the power receiving device 200 enters the power transmission area until the coupling coefficient becomes maximum and the current flowing through the power transmission device 120B becomes maximum. In other words, the possibility that the other power receiving device 200 will stop feeding power and the output power will decrease before the output power of the AC power supply device 110 exceeds the rated output power due to power feeding to the newly entering power receiving device 200 is increased. Therefore, even by such control, it is possible to further suppress the output power of the AC power supply device 110 from exceeding the rated output power.

[0068] The controller 130 and the methods described herein may be implemented by a special-purpose computer provided by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the controller 130 and the methods described herein may be implemented by a special-purpose computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the controller 130 and the methods described herein may be implemented by one or more special-purpose computers configured by a combination of a processor and memory programmed to perform one or more functions and a processor configured with one or more hardware logic circuits. The computer program may also be stored in a computer-readable non-transitory tangible recording medium as instructions executed by the computer.

[0069] The present disclosure is not limited to the above-mentioned embodiment, and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features in each embodiment corresponding to the technical features in the form described in the Summary of the Invention column can be appropriately replaced or combined in order to solve some or all of the above-mentioned problems or to achieve some or all of the above-mentioned effects. Furthermore, if the technical feature is not described as essential in this specification, it can be appropriately deleted. (Form 1) A non-contact power supply system (1000, 1000A, 1000B, 1000C, 1000D), an AC power supply device (110, 110C) that supplies AC power at a predetermined operating frequency; A plurality of power transmission devices (120, 120A, 120B) connected in parallel to the AC power supply device, each of the power transmission devices having a primary side resonant circuit (10, 10A) including a primary side coil (Ls) and a primary side capacitor (Cs); A power receiving device (200, 200C) that receives power from the power transmitting device in a non-contact manner, a secondary resonant circuit having a secondary coil (Lr) and a secondary capacitor (Cr) for magnetically coupling with the primary coil; a rectifier circuit (230) that rectifies AC power output from the secondary resonant circuit and converts it into DC power; A power receiving side control unit (220) for controlling the rectifier circuit; A load device (210) to which the DC power is supplied at a constant current; A power receiving device having a power supply voltage control unit (140) for controlling an output voltage of the AC power supply device; Equipped with the power supply voltage control unit performs a primary side power suppression control to reduce the output voltage so that the output voltage falls below a preset allowable output power when the output power of the AC power supply device exceeds a rated output power of the AC power supply device. Contactless power supply system. (Form 2) The wireless power supply system according to aspect 1, Each of the plurality of power transmitting devices includes an impedance variable element (20) connected between the primary coil and the AC power supply device for switching a state of the power transmission device between a power transmission state and a standby state; a primary side detection circuit (30) for detecting either the magnitude of a magnetic flux interlinked with the primary side coil or the magnitude of a magnetic flux in the vicinity of the primary side coil; a primary side control circuit (40) that changes the impedance of the impedance variable element by utilizing a detection value by the primary side detection circuit; Further equipped with The primary side control circuit determines a state of the power transmitting device as In a first case where the primary side detection circuit detects an increase in magnetic flux linking with the primary side coil or in the vicinity of the primary side coil, the impedance of the impedance variable element is reduced to transition from the standby state to the power transmission state; In a second case where the primary side detection circuit detects a decrease in the magnetic flux linking with the primary side coil or in the vicinity of the primary side coil, the impedance of the impedance variable element is increased to transition from the power transmission state to the standby state. Contactless power supply system. (Form 3) The wireless power supply system according to aspect 2, When the primary-side power limiting control is being performed, the primary-side control circuit does not transition from the standby state to the power transmission state even in the first case. Contactless power supply system. (Form 4) The wireless power supply system according to aspect 3, Each of the power transmission devices further includes a voltage detection circuit (50) for detecting a voltage supplied to the power transmission device; When the voltage detected by the voltage detection circuit is less than a preset threshold value, the primary side control circuit does not transition from the standby state to the power transmission state even in the first case. Contactless power supply system. (Form 5) The wireless power supply system according to any one of aspects 1 to 4, The power supply voltage control unit notifies the power receiving device that the primary side power limiting control is being performed when the primary side power limiting control is being performed. Contactless power supply system. (Form 6) The wireless power supply system according to aspect 5, The power supply voltage control unit prohibits the power receiving device from newly starting power supply when the primary side power limiting control is being performed. Contactless power supply system. (Form 7) The wireless power supply system according to aspect 5 or 6, When the power receiving control unit receives the notification, the power receiving control unit controls the rectifier circuit to perform secondary-side power suppression control for suppressing the secondary-side power supplied to the load device, thereby suppressing the secondary-side power so that a ratio of the secondary-side power after the secondary-side power suppression control to the secondary-side power before the secondary-side power suppression control is a predetermined suppression rate. Contactless power supply system. (Form 8) The wireless power supply system according to aspect 7, The suppression rate is a value obtained by dividing the rated output power by a value obtained by multiplying the rated power consumption of the power receiving device by the number of the power receiving devices. Contactless power supply system. (Form 9) The wireless power supply system according to aspect 7, The suppression rate is a value obtained by dividing the rated output voltage of the AC power supply device by the current output voltage. Contactless power supply system. (Form 10) A computer program for controlling a wireless power supply system, The wireless power supply system includes: an AC power supply device that supplies AC power at a predetermined operating frequency; A plurality of power transmission devices connected in parallel to the AC power supply device, each of the power transmission devices having a primary-side resonant circuit including a primary-side coil and a primary-side capacitor; A power receiving device that receives power from the power transmitting device in a non-contact manner, a secondary resonant circuit having a secondary coil and a secondary capacitor for magnetically coupling with the primary coil; a rectifier circuit that rectifies the AC power output from the secondary resonant circuit to convert it into DC power; A power receiving side control unit that controls the rectifier circuit; A load device to which the DC power is supplied at a constant current; A power receiving device having Equipped with The computer program comprises: causing a computer to realize a function of reducing an output voltage of the AC power supply device so that the output voltage falls below a preset allowable output power when the output power of the AC power supply device exceeds a rated output power of the AC power supply device; Computer program. (Form 11) A power transmitting device that wirelessly supplies power to a power receiving device, The power transmitting device has a primary-side resonant circuit having a primary-side coil and a primary-side capacitor, and is connected in parallel with other power transmitting devices to an AC power supply device that supplies AC power of a predetermined operating frequency; The power receiving device is a secondary resonant circuit having a secondary coil and a secondary capacitor for magnetically coupling with the primary coil; a rectifier circuit that rectifies the AC power output from the secondary resonant circuit to convert it into DC power; A power receiving side control unit that controls the rectifier circuit; A load device to which the DC power is supplied at a constant current; having When the output power of the AC power supply device exceeds a rated output power of the AC power supply device, the AC power supply device reduces the output voltage of the AC power supply device so that the output voltage falls below a preset allowable output power. Power transmission equipment. (Form 12) A power receiving device that receives power from a power transmitting device in a wireless manner, The power transmitting device has a primary-side resonant circuit having a primary-side coil and a primary-side capacitor, and is connected in parallel with another power transmitting device to an AC power supply device that supplies AC power having a predetermined operating frequency, The power receiving device is a secondary resonant circuit having a secondary coil and a secondary capacitor for magnetically coupling with the primary coil; a rectifier circuit that rectifies the AC power output from the secondary resonant circuit to convert it into DC power; A power receiving side control unit that controls the rectifier circuit; A load device to which the DC power is supplied at a constant current; having When the output power of the AC power supply device exceeds a rated output power of the AC power supply device, the AC power supply device reduces the output voltage of the AC power supply device so that the output voltage falls below a preset allowable output power. Powered device. [Explanation of symbols]

[0070] 10, 10A...primary side resonant circuit, 110, 110C...AC power supply device, 120, 120A, 120B...power transmission device, 140...power supply voltage control unit, 200, 200C...power receiving device, 210...battery, 220...power receiving side control unit, 230...rectifier circuit, 240...secondary side resonant circuit, 1000, 1000A, 1000B, 1000C, 1000D...non-contact power supply system, Cr...secondary side capacitor, Cs...primary side capacitor, Lr...secondary side coil, Ls...primary side coil

Claims

1. A non-contact power supply system (1000, 1000A, 1000B, 1000C, 1000D), An AC power supply device (110, 110C) that supplies AC power at a predetermined operating frequency; A plurality of power transmission devices (120, 120A, 120B) connected in parallel to the AC power supply device, each of the power transmission devices having a primary side resonant circuit (10, 10A) including a primary side coil (Ls) and a primary side capacitor (Cs); A power receiving device (200, 200C) that receives power from the power transmitting device in a non-contact manner, a secondary resonant circuit having a secondary coil (Lr) for magnetically coupling with the primary coil and a secondary capacitor (Cr); a rectifier circuit (230) that rectifies AC power output from the secondary resonant circuit and converts it into DC power; A power receiving side control unit (220) for controlling the rectifier circuit; A load device (210) to which the DC power is supplied at a constant current; A power receiving device having A power supply voltage control unit (140) for controlling an output voltage of the AC power supply device; Equipped with the power supply voltage control unit performs a primary side power suppression control to reduce the output voltage so that the output voltage falls below a preset allowable output power when the output power of the AC power supply device exceeds a rated output power of the AC power supply device. Contactless power supply system.

2. The non-contact power supply system according to claim 1, Each of the plurality of power transmitting devices includes an impedance variable element (20) connected between the primary coil and the AC power supply device for switching the state of the power transmission device between a power transmission state and a standby state; a primary side detection circuit (30) for detecting either the magnitude of a magnetic flux interlinked with the primary coil or the magnitude of a magnetic flux in the vicinity of the primary coil; a primary side control circuit (40) for changing the impedance of the impedance variable element by utilizing a detection value by the primary side detection circuit; Further equipped with The primary side control circuit determines a state of the power transmitting device as In a first case in which the primary side detection circuit detects an increase in magnetic flux linking with the primary side coil or in the vicinity of the primary side coil, the impedance of the impedance variable element is reduced to transition from the standby state to the power transmission state; a second case in which the primary side detection circuit detects a decrease in the magnetic flux linking with the primary side coil or in the vicinity of the primary side coil, the impedance of the impedance variable element is increased to transition from the power transmission state to the standby state; Contactless power supply system.

3. The non-contact power supply system according to claim 2, When the primary-side power limiting control is being performed, the primary-side control circuit does not transition from the standby state to the power transmission state even in the first case. Contactless power supply system.

4. The non-contact power supply system according to claim 3, Each of the power transmission devices further includes a voltage detection circuit (50) for detecting a voltage supplied to the power transmission device; When the voltage detected by the voltage detection circuit is less than a preset threshold value, the primary side control circuit does not transition from the standby state to the power transmission state even in the first case. Contactless power supply system.

5. The non-contact power supply system according to any one of claims 1 to 4, The power supply voltage control unit notifies the power receiving device that the primary side power limiting control is being performed when the primary side power limiting control is being performed. Contactless power supply system.

6. The non-contact power supply system according to claim 5, The power supply voltage control unit prohibits the power receiving device from newly starting power supply when the primary side power limiting control is being performed. Contactless power supply system.

7. The non-contact power supply system according to claim 5, When the power receiving control unit receives the notification, the power receiving control unit controls the rectifier circuit to perform secondary-side power suppression control for suppressing the secondary-side power supplied to the load device, thereby suppressing the secondary-side power so that a ratio of the secondary-side power after the secondary-side power suppression control to the secondary-side power before the secondary-side power suppression control is a predetermined suppression rate. Contactless power supply system.

8. The non-contact power supply system according to claim 7, The suppression rate is a value obtained by dividing the rated output power of the AC power supply device by a value obtained by multiplying the rated power consumption of the power receiving device by the number of the power receiving devices. Contactless power supply system.

9. The non-contact power supply system according to claim 7, The suppression rate is a value obtained by dividing the rated output voltage of the AC power supply device by the current output voltage. Contactless power supply system.

10. A computer program for controlling a wireless power supply system, The wireless power supply system includes: an AC power supply device that supplies AC power at a predetermined operating frequency; A plurality of power transmission devices connected in parallel to the AC power supply device, each of the power transmission devices having a primary-side resonant circuit including a primary-side coil and a primary-side capacitor; A power receiving device that receives power from the power transmitting device in a non-contact manner, a secondary resonant circuit having a secondary coil and a secondary capacitor for magnetically coupling with the primary coil; a rectifier circuit that rectifies the AC power output from the secondary resonant circuit to convert it into DC power; A power receiving side control unit that controls the rectifier circuit; A load device to which the DC power is supplied at a constant current; A power receiving device having Equipped with The computer program comprises: causing a computer to realize a function of reducing an output voltage of the AC power supply device so that the output voltage falls below a preset allowable output power when the output power of the AC power supply device exceeds a rated output power of the AC power supply device; Computer program.

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