Notification device, non-contact power supply system, computer program, power transmission device, and power reception device

Abstract

A notification device (300) is used in a non-contact power supply system (1000) having a power reception device (200) and a power transmission device (100) that transmits power to the power reception device in a non-contact manner. The notification device (300) comprises: a notification unit (320) that outputs a power suppression signal requesting suppression of power during power transmission by the power transmission device; and a power supply unit (310, 310A) that supplies power for the operation of the notification unit.

Description

Notification device, contactless power supply system, computer program, power transmitting device, and power receiving device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2023-196082, filed on November 17, 2023, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a notification device, a contactless power supply system, a power transmitting device, and a power receiving device.

[0003] There is known a contactless power transfer system that transmits power from a power transmitting device and supplies power to a vehicle equipped with a power receiving device. In such a contactless power transfer system, there is a risk of being affected by an electromagnetic field if a person is present near the power transmitting device during power transfer. The contactless power transfer system described in Patent Document 1 reduces the effect of the electromagnetic field on the living body by suppressing the power supply when a sensor such as a camera detects a living body.

[0004] JP 2012-165497 A

[0005] However, in Patent Document 1, the power supply is suppressed when a sensor such as a camera detects a living body, which causes the power supply to be excessively suppressed even when there is no risk of the electromagnetic field actually affecting the living body. Therefore, a technology that can suppress the power supply in appropriate situations is desired.

[0006] The present disclosure can be realized in the following forms.

[0007] According to one aspect of the present disclosure, there is provided a notification device for use in a contactless power supply system having a power receiving device and a power transmitting device that transmits power to the power receiving device in a contactless manner, the notification device including: a notification unit that outputs a power suppression signal requesting suppression of power when transmitting power from the power transmitting device; and a power supply unit that supplies power for operating the notification unit.

[0008] According to this type of notification device, a power transmission prohibition signal is output requesting that the power transmitted by the power transmission device be reduced. Therefore, when the notification device attached to a living body is located near the power transmission device, it can request that the power transmitted by the power transmission device be reduced, thereby preventing excessive restrictions on opportunities for power transmission by the power transmission device.

[0009] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is an explanatory diagram showing a schematic configuration of a contactless power transfer system according to a first embodiment, Fig. 2 is an explanatory diagram showing the circuit configurations of a power transmitting device and a power receiving device according to the first embodiment, Fig. 3 is a flowchart showing a control procedure in the contactless power transfer system according to the first embodiment, and Fig. 4 is an explanatory diagram showing the circuit configuration of a power supply unit according to a second embodiment.

[0010] A. First Embodiment: A-1. System Configuration: A contactless power transfer system 1000 of this embodiment shown in FIG. 1 includes a power transmission device 100, a power receiving device 200, and a notification device 300. In this embodiment, the power transmission device 100 is buried under a track 105. Note that at least a portion of the power transmission device 100 may be installed on the track 105. The power receiving device 200 is mounted on an electric vehicle 202 that serves as a mobile body that travels on the track 105. In this embodiment, the electric vehicle 202 is configured as an AGV (Automatic Guided Vehicle) that travels within a factory or warehouse. Note that, although FIG. 1 shows the contactless power transfer system 1000 including one power transmission device 100 and one power receiving device 200, the system may include a plurality of power transmission devices 100 and one power receiving device 200.

[0011] 1, the notification device 300 is shown positioned below the runway 105 for convenience of illustration, but the notification device 300 is actually positioned above the runway 105. In this embodiment, the notification device 300 is attached to the work shoes of a worker walking on the runway 105 and moves with the worker. The specific configuration of the notification device 300 will be described later.

[0012] In the contactless power supply system 1000, the power transmission device 100 supplies power to the power receiving device 200 when the electric vehicle 202 travels on a 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 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 vertically upward direction.

[0013] The power transmission device 100 includes an AC power supply device 110, a plurality of power transmission circuits 120, and a control device 130. The AC power supply device 110 supplies AC power at a predetermined operating frequency to each of the power transmission circuits 120. The specific configuration of the AC power supply device 110 will be described later.

[0014] The multiple power transmission circuits 120 are installed underground along the x-axis direction of the track 105. The power transmission circuits 120 may be installed in a location other than underground on the track 105, for example, on the side of the transportation facility. The power transmission circuits 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 circuit 120 includes a primary-side resonant circuit 10 and a power transmission control circuit 20. The primary-side resonant circuit 10 receives AC power from the AC power supply device 110 and wirelessly transmits the AC power to a secondary-side resonant circuit 240 (described later). The power transmission control circuit 20 switches between performing and not performing power transmission by the primary-side resonant circuit 10 depending on the relative positions of the power transmission device 100 and the power receiving device 200. Specific configurations of the primary-side resonant circuit 10 and the power transmission control circuit 20 will be described later.

[0015] 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 transmission control unit 140 by executing a program stored in advance in the memory 132.

[0016] The power transmission control unit 140 controls whether to start or stop the power supply by the AC power supply device 110. More specifically, the power transmission control unit 140 controls whether to start or stop the power supply depending on the reception status of a power transmission prohibition signal output from a notification device 300, which will be described later. Specific processing by the power transmission control unit 140 will be described later. In this embodiment, the control device 130 is disposed near each power transmission circuit 120. Therefore, the control device 130 can receive the power transmission prohibition signal output when a worker carrying a communication device 133 approaches the power transmission circuit 120, and the power transmission control unit 140 can execute control of whether to start or stop the power supply at the timing when this control is necessary.

[0017] 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 device 290. The power receiving device 200 does not necessarily include the auxiliary device 290. In this case, the power receiving device 200 does not necessarily include the auxiliary battery 215 or the DC / DC converter circuit 260. In this embodiment, the secondary-side resonant circuit 240 is provided in a position facing the road 105, for example, on the underside of the electric vehicle 202. In addition, if the power transmitting circuit 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.

[0018] The secondary-side resonant circuit 240 is connected to a rectifier circuit 230, and AC power received by the secondary-side resonant circuit 240 is converted into DC power by the rectifier circuit 230. The output of the rectifier circuit 230 is connected to the battery 210, the high-voltage side of a DC / DC converter circuit 260, and an inverter circuit 270. The low-voltage side of the DC / DC converter circuit 260 is connected to an auxiliary battery 215 and an auxiliary device 290. The inverter circuit 270 is connected to a motor generator 280. The DC power output from the rectifier circuit 230 can be used to charge the battery 210 or drive the motor generator 280 via the inverter circuit 270. Furthermore, by stepping down the DC power output from the rectifier circuit 230 using the DC / DC converter circuit 260, the DC power can also be used to charge the auxiliary battery 215 or drive the auxiliary device 290.

[0019] Battery 210 is a secondary battery that outputs relatively high DC power, for example, a voltage of several tens to several hundreds of volts, for driving motor generator 280. Motor generator 280 operates as a three-phase AC motor and generates driving force for running electric vehicle 202. Motor generator 280 operates as a generator and regenerates electric power when electric vehicle 202 decelerates. When motor generator 280 operates as a motor, inverter circuit 270 converts the power of battery 210 into three-phase AC and supplies it to motor generator 280. When motor generator 280 operates as a generator, inverter circuit 270 converts the three-phase AC regenerated by motor generator 280 into DC and supplies it to battery 210.

[0020] 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 various accessories such as a camera, various sensors such as Lidar, and lights that are used for driving the electric vehicle 202. The auxiliary battery 215 may also be used as a power source for the control device 130.

[0021] The power receiving side control unit 220 controls the inverter circuit 270 and other units in the electric vehicle 202 .

[0022] The notification device 300 outputs a power transmission prohibition signal. The "power transmission prohibition signal" refers to a signal that requests prohibition of power transmission by the power transmission device 100. In other words, the power transmission prohibition signal is a signal that requests that the power transmission device 100 reduce the power transmitted to zero, and corresponds to the "power reduction signal" in the present disclosure.

[0023] Notification device 300 includes power supply unit 310, notification unit 320, and magnetic field sensor 330. Power supply unit 310 supplies power for operation of notification unit 320 and magnetic field sensor 330 to each of notification unit 320 and magnetic field sensor 330. In this embodiment, power supply unit 310 is configured as a battery. Notification device 300 operates using power supplied by power supply unit 310 configured as a battery, which prevents the configuration of notification device 300 from becoming complicated and large.

[0024] The magnetic field sensor 330 is a sensor that detects a magnetic field. In this embodiment, the magnetic field sensor 330 has a detection circuit that resonates in a frequency band corresponding to the frequency of the magnetic field generated when the power transmitting device 100 transmits power. When the power transmitting device 100 transmits power and generates a magnetic field, the detection circuit resonates, the impedance decreases, and a current flows. In this embodiment, the magnetic field sensor 330 detects the generation of a magnetic field by detecting the current. Furthermore, when the magnetic field sensor 330 detects the generation of a magnetic field, it outputs a signal to the notification unit 320. Note that the magnetic field sensor 330 is not limited to the above configuration and may be any known type of magnetic field sensor 330.

[0025] The notification unit 320 is configured to be able to switch ON / OFF the output of the power transmission prohibition signal. In the present embodiment, the notification unit 320 turns ON the output of the power transmission prohibition signal when it receives a signal from the magnetic field sensor 330. In the present embodiment, the transmission distance of the power transmission prohibition signal in the ON state is 2 m. More specifically, in the output ON state, the notification unit 320 outputs a power transmission prohibition signal with an intensity that can be received by the communication device 133 of the control device 130 located within 2 m of the notification unit 320, but cannot be received by the communication device 133 of the control device 130 located more than 2 m away from the notification unit 320. Therefore, when the contactless power supply system 1000 includes multiple power transmission devices 100, the power transmission devices 100 that stop power transmission can be limited to the power transmission devices 100 located within 2 m of the notification device 300, thereby preventing excessive restriction on opportunities for power transmission by the power transmission devices 100. On the other hand, in the OFF state, the notification unit 320 does not output a power transmission prohibition signal, which can reduce power consumption in the notification device 300 compared to a configuration in which the power transmission prohibition signal is always output.

[0026] A-2. Circuit Configuration: The circuit configuration of the power transmission device 100 will be described. As shown in FIG. 2 , the AC power supply device 110 includes a power supply PS, an inverter circuit INV, and a filter circuit FL. In this embodiment, the power supply PS is a DC power supply that supplies DC power to the inverter circuit INV. The inverter circuit INV converts the supplied DC power into high-frequency AC power. The high-frequency filter 114 extracts and passes AC power of a predetermined operating frequency from the supplied high-frequency AC power. In this embodiment, the control device 130 controls the inverter circuit INV to enable or disable power supply by the AC power supply device 110. Note that the power supply PS is not limited to a DC power supply, and may also be an AC power supply that supplies AC power. In this configuration, an AC / DC converter circuit is provided between the power supply PS and the inverter circuit INV. The AC / DC converter circuit converts the AC power supplied from the power supply PS into DC power and supplies it to the inverter circuit INV.

[0027] In this embodiment, as described above, the power transmission circuit 120 includes the primary-side resonant circuit 10 and the power transmission control circuit 20. Note that, in Fig. 2, of the multiple power transmission circuits 120 connected in parallel to the AC power supply device 110, only one power transmission circuit 120 is shown, and the other power transmission circuits 120 are not shown.

[0028] The primary-side resonant circuit 10 includes a primary-side coil Ls and a variable impedance element 12. The variable impedance element 12 is connected in series with the primary-side coil Ls between the AC power supply device 110 and the primary-side coil Ls. The variable impedance element 12 includes two capacitors C11 and C12 and a switch SW. The capacitor C11 and the primary-side coil Ls are connected in series. The capacitor C12 and the switch SW are connected in series, and the series-connected capacitor C12 and switch SW are connected in parallel with the capacitor C11. The switch SW may be a mechanical contact such as a relay that switches in response to an external command, or may be configured using a semiconductor element such as a MOS-FET or an analog switch.

[0029] The capacitance of the variable impedance element 12 changes when the switch SW is switched on and off. When the switch SW is on, the capacitor C12 is connected to the primary coil Ls. At this time, the capacitance of the variable impedance element 12 is equal to the sum of the capacitance of the capacitor C11 and the capacitance of the capacitor C12. When the switch SW is off, the capacitor C12 is disconnected from the primary coil Ls. At this time, the capacitance of the variable impedance element 12 is equal to the capacitance of the capacitor C11. As the capacitance of the variable impedance element 12 changes in this way, the impedance of the primary side resonant circuit 10 when the switch SW is on decreases compared to when the switch SW is off. The resonant state of the primary side resonant circuit 10 also changes in accordance with this change in impedance of the primary side resonant circuit 10. In this embodiment, when the switch SW is on, the primary side resonant circuit 10 is in a resonant state at the operating frequency and in a power transmission state. On the other hand, when the switch SW is off, the primary side resonant circuit 10 is in a non-resonant state at the operating frequency and is in a standby state.

[0030] The power transmission control circuit 20 includes a primary-side detection circuit 22 and a primary-side control circuit 24. The primary-side detection circuit 22 includes a magnetic flux sensor (not shown) that detects the magnitude of the magnetic flux interlinked with the primary coil Ls and a current sensor (not shown) that detects the magnitude of the current flowing through the primary coil Ls. In this embodiment, the magnetic flux sensor detects the magnitude of the magnetic flux by utilizing changes in voltage across a detection coil magnetically coupled to the primary coil Ls. The current sensor detects the magnitude of the current by utilizing changes in voltage across a capacitor C11. The primary-side detection circuit 22 outputs a signal indicating the magnitude of the detected magnetic flux and a signal indicating the magnitude of the current to the primary-side control circuit 24.

[0031] The primary-side control circuit 24 uses the signal output from the primary-side detection circuit 22 to drive the switch SW to switch the switch SW on and off. More specifically, when the magnitude of the magnetic flux indicated by the signal output from the primary-side detection circuit 22 is equal to or greater than a preset threshold, the primary-side control circuit 24 turns on the switch SW and switches the primary-side resonant circuit 10 to a power transmission state. Furthermore, when the magnitude of the current indicated by the signal output from the primary-side detection circuit 22 is equal to or greater than a threshold, the primary-side control circuit 24 turns off the switch SW and switches the primary-side resonant circuit 10 to a standby state. In this embodiment, the switch SW is configured as a normally open switch, and the primary-side resonant circuit 10 normally maintains the standby state, more specifically, when the magnitude of the magnetic flux is less than the threshold.

[0032] The magnitude of the current and the magnitude of the magnetic flux change depending on the degree of magnetic coupling between the power transmission circuit 120 and the power receiving device 200. In a non-resonant state, the magnitude of the magnetic flux increases as the power transmission circuit 120 and the power receiving device 200 approach each other. In a resonant state, the magnitude of the current decreases as the power transmission circuit 120 and the power receiving device 200 approach each other. The threshold values ​​of the magnitude of the magnetic flux and the magnitude of the current are determined and set in advance by performing simulations or the like as values ​​when the power receiving device 200 enters the power transmission area. The "power transmission area" refers to an area predetermined for each power transmission circuit 120 as an area in which power transmission to the power receiving device 200 is performed. In other words, the primary-side control circuit 24 controls the switching of the switch SW to start power transmission when the power receiving device 200 enters the power transmission area. This makes it possible to suppress power supply to the power transmission circuit 120 when the power receiving device 200 is not located within the power transmission area, thereby suppressing power consumption in the contactless power transfer system 1000.

[0033] A description will be given of the circuit configuration of the power receiving device 200. Note that Fig. 2 particularly illustrates the circuit configuration of the power receiving device 200 related to power supply to the battery 210, and omits other parts.

[0034] The secondary-side resonant circuit 240 includes a secondary-side coil Lr and a secondary-side capacitor Cr connected in series. The secondary-side resonant circuit 240 is configured to be in a resonant state at the operating frequency of the power transmitting device 100. In the resonant state, the secondary-side resonant circuit 240 receives AC power transmitted from the power transmitting device 100 and supplies the received AC power to the rectifier circuit 230.

[0035] In this embodiment, the rectifier circuit 230 is configured as a diode bridge. The rectifier circuit 230 rectifies the AC power supplied from the secondary-side resonant circuit 240 and supplies the rectified DC power to the battery 210. The battery 210 is charged by the DC power supplied from the rectifier circuit 230.

[0036] A-3. Control in Contactless Power Transfer System 1000: In this embodiment, the control shown in Fig. 3 is repeatedly executed during operation of the contactless power transfer system 1000. Steps S110, S120, and S130 shown on the left side of Fig. 3 are controls executed in the notification device 300. Steps S210 to S280 shown on the right side of Fig. 3 are controls executed in the power transmission device 100.

[0037] The control in the notification device 300 will be described. If a magnetic field is detected by the magnetic field sensor 330 (step S110: Yes), in step S120, the notification unit 320 turns on the output of the power transmission prohibition signal. On the other hand, if a magnetic field is not detected (step S110: No), in step S130, the notification unit 320 turns off the output of the power transmission prohibition signal. The notification device 300 repeatedly executes the above control while the notification device 300 is operating.

[0038] Control in the power transmission device 100 will now be described. In Fig. 3, it is assumed that the primary-side resonant circuit 10 is in a standby state at the start. In step S210, the primary-side control circuit 24 determines whether the power receiving device 200 is located within the power transmission area. In this embodiment, the primary-side control circuit 24 determines whether the magnitude of the magnetic flux indicated by the signal output from the primary-side detection circuit 22 is equal to or greater than a preset threshold value, thereby determining whether the power receiving device 200 is located within the power transmission area.

[0039] If it is determined that the power receiving device 200 is located within the power transmission area (step S210: Yes), in other words, if it is determined that the magnitude of the magnetic flux indicated by the signal output from the primary-side detection circuit 22 is equal to or greater than a preset threshold, in step S220, the primary-side detection circuit 22 controls the switch SW to switch the primary-side resonant circuit 10 to the power transmission state. On the other hand, if it is determined that the power receiving device 200 is not located within the power transmission area (step S210: No), in other words, if it is determined that the magnitude of the magnetic flux indicated by the signal output from the primary-side detection circuit 22 is less than the preset threshold, the primary-side detection circuit 22 keeps the primary-side resonant circuit 10 in the standby state.

[0040] In step S230, the power transmission control unit 140 determines whether a power transmission prohibition signal is being received. If it is determined that a power transmission prohibition signal is being received (step S230: Yes), the power transmission control unit 140 stops the AC power supply device 110 from supplying power to the power transmission circuit 120. If a power transmission prohibition signal is received, it is assumed that a worker carrying the notification device 300 is located near the power transmission device 100. If power transmission is continued in such a situation, the magnetic field generated during power transmission may affect the worker. In this embodiment, if it is determined that a power transmission prohibition signal is being received, the AC power supply device 110 stops supplying power to the power transmission circuit 120, thereby preventing the magnetic field generated during power transmission from affecting the worker.

[0041] On the other hand, if it is determined that the power transmission prohibition signal is not being received (step S230: No), in step S270, the power transmission control unit 140 determines whether a predetermined waiting time has elapsed since the reception of the power transmission prohibition signal stopped. The waiting time may be set to any length that can suppress the occurrence of a hunting phenomenon, which will be described later. If it is determined that the waiting time has not elapsed (step S270: No), the power transmission control unit 140 executes step S240, in other words, continues to stop the supply of power to the power transmission circuit 120. On the other hand, if it is determined that the waiting time has elapsed (step S270: Yes), in step S280, the power transmission control unit 140 causes the AC power supply device 110 to supply power to the power transmission circuit 120.

[0042] When the power supply is stopped upon receiving the power transmission prohibition signal, a magnetic field is no longer generated, and the notification device 300 stops outputting the power transmission prohibition signal. If the power supply were to be resumed immediately after the power transmission prohibition signal was stopped, the worker carrying the notification device 300 would still be considered to be near the power transmitting device 100. Therefore, when the power supply is resumed, a magnetic field would be generated again, the power transmission prohibition signal would be output, and the power supply would be stopped upon receiving the power transmission prohibition signal. In other words, if the power supply were resumed immediately after the power transmission prohibition signal was stopped, a hunting phenomenon could occur, in which the power supply is repeatedly restarted and stopped within a short period of time. In this embodiment, the power supply is resumed after a waiting time has elapsed after the power transmission prohibition signal is stopped, thereby preventing the occurrence of such a hunting phenomenon.

[0043] In step S250, the primary-side control circuit 24 determines whether the power receiving device 200 is located within the power transmission area. In this embodiment, the primary-side control circuit 24 determines whether the magnitude of the current indicated by the signal output from the primary-side detection circuit 22 is equal to or greater than a threshold value, thereby determining whether the power receiving device 200 is located within the power transmission area.

[0044] If it is determined that the power receiving device 200 is located within the power transmission area (step S250: Yes), in other words, if it is determined that the magnitude of the current indicated by the signal output from the primary-side detection circuit 22 is less than the threshold, the power transmission control unit 140 executes the above-mentioned step S230 again. On the other hand, if it is determined that the power receiving device 200 is located within the power transmission area (step S250: No), in other words, if it is determined that the magnitude of the current indicated by the signal output from the primary-side detection circuit 22 is equal to or greater than the threshold, in step S260, the primary-side detection circuit 22 controls the switch SW to switch the primary-side resonant circuit 10 to the standby state. The notification device 300 repeatedly executes the above control while the notification device 300 is operating.

[0045] According to the first embodiment of the contactless power supply system 1000 described above, the notification device 300 outputs a power transmission prohibition signal requesting that the power transmitted by the power transmission device 100 be reduced. Therefore, when the notification device 300 attached to a living body is located near the power transmission device 100, it can request that the power transmitted by the power transmission device 100 be reduced, thereby preventing excessive restriction on opportunities for power transmission by the power transmission device 100.

[0046] Furthermore, since the transmission distance of the power transmission prohibition signal is within 2 m, the power transmission devices 100 that stop power transmission can be limited to power transmission devices 100 located within 2 m of the notification device 300, thereby further preventing excessive restriction of opportunities for power transmission by the power transmission devices 100.

[0047] Furthermore, the notification device 300 has a magnetic field sensor 330, and the notification unit 320 outputs a power transmission prohibition signal when the magnetic field sensor 330 detects a magnetic field, so that a request to stop power transmission can be made only in a situation where a magnetic field is actually being generated and there is a risk of a worker being exposed to the magnetic field, thereby further preventing excessive restrictions on opportunities for power transmission by the power transmission device 100. Furthermore, compared to a configuration in which a power transmission prohibition signal is always output, an increase in power consumption in the notification device 300 can be prevented.

[0048] Furthermore, the magnetic field sensor 330 is equipped with a detection circuit that resonates in a frequency band corresponding to the frequency of the magnetic field generated when the power transmission device 100 transmits power, and is therefore capable of detecting a weak magnetic field and accurately detecting the generation of a magnetic field.

[0049] B. Second Embodiment: The notification device 300 included in the contactless power transfer system 1000 of the second embodiment differs from the notification device 300 included in the contactless power transfer system 1000 of the first embodiment in that it has a power supply unit 310A shown in Fig. 4 instead of the power supply unit 310. Note that the device configuration of the contactless power transfer system 1000 of the second embodiment and other steps of the processing in the contactless power transfer system 1000 are the same as those in the contactless power transfer 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.

[0050] 4, the power supply unit 310A of this embodiment includes a resonant circuit 312, a rectifier circuit 314, and a battery 316. The resonant circuit 312 includes a coil Lc and a capacitor Cc connected in series. The resonant circuit 312 is configured to resonate at the operating frequency of the power transmitting device 100. In the resonant state, the resonant circuit 312 supplies AC power to the rectifier circuit 314, the AC power being generated due to the energy of a magnetic field generated when the power transmitting device 100 transmits power.

[0051] The rectifier circuit 314 is configured as a diode bridge. The rectifier circuit 314 rectifies the AC power supplied from 312 and supplies the rectified DC power to the battery 316. The battery 316 is charged by receiving the DC power from the rectifier circuit 314. In this manner, in this embodiment, the battery 316 is charged by utilizing the energy of the magnetic field generated when the power transmitting device 100 transmits power. The battery 316 corresponds to the "power storage unit" in the present disclosure. Note that the power supply unit 310A may include a capacitor as the power storage unit instead of the battery 316.

[0052] According to the wireless power supply system 1000 of the second embodiment described above, the power supply unit 310 has the battery 316 that is charged using the energy of the magnetic field generated when the power transmitting device 100 transmits power, so it is possible to prevent the power transmission prohibition signal from being unable to be output due to a lack of power remaining in the driving battery. In addition, since a driving battery is not required, it is possible to prevent the notification device 300 from becoming larger.

[0053] C. Other Embodiments: (C1) In the above embodiment, the notification device 300 is attached to the worker's work shoes, but the present disclosure is not limited to this. The notification device 300 is not limited to work shoes, and may be attached to any location carried by the worker, such as a hat. Note that the notification device 300 is preferably attached to a location that is close to the power transmission device 100. This configuration also achieves the same effects as the above embodiment.

[0054] Furthermore, the notification device 300 may be used not only to protect workers but also to protect precision machinery and the like that is susceptible to the effects of magnetic fields. More specifically, the notification device 300 may be attached to a cart used to transport the precision machinery. In this configuration, power supply is stopped when the cart equipped with the notification device 300 passes near the power transmitting device 100, thereby preventing the precision machinery and the like that are susceptible to the effects of magnetic fields from being affected by the magnetic field.

[0055] (C2) In the above embodiment, the power transmission control unit 140 stops the power supply upon receiving a power transmission prohibition signal. However, the present disclosure is not limited to this. Instead of the power transmission prohibition signal, the notification device 300 may output a power suppression signal requesting that the power transmission device 100 suppress power during power transmission. Upon receiving the power suppression signal, the power transmission control unit 140 may execute control to suppress the power during power transmission compared to normal without stopping the power supply. In this embodiment, the power transmission control unit 140 controls the power during power transmission, for example, by controlling the duty ratio of the inverter circuit INV. This embodiment also suppresses the power during power transmission, thereby reducing the strength of the magnetic field generated during power transmission compared to normal, thereby preventing the magnetic field generated during power transmission from affecting the worker. The suppression of the transmission power may be achieved by changing the drive frequency of the inverter circuit INV. In this embodiment, the power transmission control unit 140 changes the drive frequency of the inverter circuit INV within a range in which the magnetic field sensor 330 and the resonant circuit 312 included in the notification device 300 of the second embodiment operate.

[0056] (C3) In the above embodiment, the power transmission by the power transmitting device 100 is stopped by the power transmission control unit 140 controlling the inverter circuit INV of the AC power supply device 110. However, the present disclosure is not limited to this. The power transmission may be stopped by the primary side control circuit 24 receiving a power transmission prohibition signal, and the primary side control circuit 24, upon receiving the power transmission prohibition signal, controlling the switch SW to switch the power transmission circuit 120 to a standby state. The power transmission may also be stopped by the primary side control circuit 24, upon receiving the power transmission prohibition signal, controlling the inverter circuit INV of the AC power supply device 110. This configuration also achieves the same effects as the above embodiment. Additionally, since the start and stop of power supply can be controlled for each power transmission circuit 120, only the power transmission circuit 120 located near the notification device 300 provided to the worker stops power transmission, while the other power transmission circuits 120 can continue power supplying. That is, the number of power transmission circuits 120 that stop power transmission to protect workers can be reduced, and excessive limitations on opportunities for power transmission by the power transmission device 100 can be prevented.

[0057] (C4) In the above embodiment, the power transmitting device 100 includes one AC power supply device 110 for multiple power transmitting circuits 120. However, the present disclosure is not limited to this. The power transmitting device 100 may include an AC power supply device 110 and a control device 130 for each power transmitting circuit 120. Furthermore, the power supply PS of the AC power supply device 110 may be shared by multiple power transmitting circuits 120, and the inverter circuit INV, filter circuit FL, and control device 130 may be provided for each power transmitting circuit 120. This configuration also achieves the same effects as the above embodiment. Additionally, since each power transmitting circuit 120 includes an inverter circuit INV and a control device 130, power supply on / off can be controlled for each power transmitting circuit 120. Therefore, among the multiple power transmitting circuits 120, only the power transmitting circuit 120 that is located near the notification device 300 provided to the worker stops power transmission, while the other power transmitting circuits 120 can continue power supply. That is, the number of power transmission circuits 120 that stop power transmission to protect workers can be reduced, and excessive limitations on opportunities for power transmission by the power transmission device 100 can be prevented.

[0058] (C5) In the above embodiment, the power transmission control unit 140 executes step S270 in the control shown in FIG. 3 , but the present disclosure is not limited to this. The power transmission control unit 140 does not have to execute step S270. That is, the power transmission control unit 140 may immediately resume power supply when the power transmission prohibition signal is no longer received. In this embodiment, the determination of step S270 is not executed, which can prevent the control shown in FIG. 3 from becoming complicated.

[0059] (C6) In the above embodiment, notification device 300 includes magnetic field sensor 330, but the present disclosure is not limited to this. Notification device 300 does not have to include magnetic field sensor 330. Notification device 300 may always output the suppression stop signal. In this embodiment, power transmission control unit 140 does not need to execute step S110 shown in FIG. 3, which prevents the control shown in FIG. 3 from becoming complicated.

[0060] (C7) In the above embodiment, the transmission distance of the power transmission prohibition signal is 2 m, but the present disclosure is not limited to this. The transmission distance of the power transmission prohibition signal may be determined arbitrarily depending on the distance between multiple power transmission devices 100. More specifically, for example, if the power transmission devices 100 are arranged at 10 m intervals, the transmission distance of the power transmission prohibition signal may be 5 m. Furthermore, the transmission distance of the power transmission prohibition signal may be determined depending on the magnitude of the power when the power transmission device 100 transmits power. This configuration also achieves the same effects as the above embodiment.

[0061] (C8) In the above embodiment, the notification unit 320 does not output a power transmission prohibition signal in the OFF state, but the present disclosure is not limited to this. In the OFF state, the notification unit 320 may output a power transmission prohibition signal of an intensity that is not received by the communication device 133 of the control device 130. Even with this configuration, the same effects as the above embodiment can be achieved.

[0062] The notification device 300 and the control device 130, and the methods described herein, may be implemented by a special-purpose computer configured with a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the notification device 300 and the control device 130, and the methods described herein, may be implemented by a special-purpose computer configured with a processor comprising one or more dedicated hardware logic circuits. Alternatively, the notification device 300 and the control device 130, and the methods described herein, may be implemented by one or more special-purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium.

[0063] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, technical features in each embodiment corresponding to technical features in the embodiments described in the Summary of the Invention section can be appropriately substituted or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate. (Mode 1) A notification device (300) used in a contactless power supply system (1000) having a power receiving device (200) and a power transmitting device (100) that transmits power to the power receiving device in a contactless manner, the notification device comprising: a notification unit (320) that outputs a power suppression signal requesting suppression of power when transmitting power from the power transmitting device; and a power supply unit (310, 310A) that supplies power for operating the notification unit. (Mode 2) The notification device according to Mode 1, wherein the transmission distance of the power suppression signal is a predetermined distance depending on the distance between the plurality of power transmitting devices. (Mode 3) The notification device according to Mode 1 or Mode 2, wherein the transmission distance is within 2 m. (Mode 4) The notification device according to any one of Modes 1 to 3, further comprising a magnetic field sensor (330) that detects a magnetic field, wherein the notification unit outputs the power suppression signal when a magnetic field is detected by the magnetic field sensor. (Mode 5) The notification device according to Mode 4, wherein the magnetic field sensor comprises a detection circuit that is in a resonant state in a frequency band corresponding to the frequency of a magnetic field generated when the power transmission device transmits power. (Mode 6) The notification device according to any one of Modes 1 to 5, wherein the power supply unit has a power storage unit (316) that is charged using energy of a magnetic field generated when the power transmission device transmits power.(Mode 7) A contactless power supply system comprising: a power receiving device; a power transmission device that transmits power to the power receiving device in a contactless manner; and a notification device according to any one of Modes 1 to 6, wherein, when the power restriction signal is received, the power transmission device executes power transmission by the power transmission device so that power during power transmission by the power transmission device is reduced compared to before the power restriction signal was received. (Mode 8) A computer program for controlling a power transmission device included in a contactless power supply system, wherein the contactless power supply system further includes a power device to which power is supplied contactlessly by the power transmission device, and the notification device according to any one of Modes 1 to 6, and the computer program causes a computer included in the power transmission device to realize a function of controlling power transmission by the power transmission device so that, when the power restriction signal is received, power during power transmission by the power transmission device is reduced compared to before the power restriction signal was received. (Mode 9) A power transmission device that transmits power to a power receiving device in a wireless manner, wherein, when the power restriction signal output by the notification device according to any one of modes 1 to 6 is received, the power transmission device executes power transmission by the power transmission device so that power during power transmission by the power transmission device is restricted compared to before the power restriction signal is received. (Mode 10) A power receiving device to which power is transmitted in a wireless manner by a power transmission device, wherein, when the power restriction signal output by the notification device according to any one of modes 1 to 6 is received, the power transmission device executes power transmission by the power transmission device so that power during power transmission by the power transmission device is restricted compared to before the power restriction signal is received.

Claims

1. A notification device (300) for use in a contactless power supply system (1000) having a power receiving device (200) and a power transmitting device (100) that transmits power to the power receiving device in a contactless manner, comprising: a notification unit (320) that outputs a power suppression signal requesting that power be suppressed when transmitting power by the power transmitting device; and a power supply unit (310, 310A) that supplies power for operating the notification unit.

2. A notification device according to claim 1, wherein the transmission distance of the power curtailment signal is a distance that is determined in advance according to the distance between the plurality of power transmitting devices.

3. The notification device according to claim 2, wherein the transmission distance is within 2 m.

4. A notification device according to claim 1, further comprising a magnetic field sensor (330) for detecting a magnetic field, wherein the notification unit outputs the power suppression signal when a magnetic field is detected by the magnetic field sensor.

5. A notification device according to claim 4, wherein the magnetic field sensor includes a detection circuit that is in a resonant state in a frequency band corresponding to the frequency of a magnetic field generated during power transmission by the power transmission device.

6. A notification device according to claim 1, wherein the power supply unit has a power storage unit (316) that is charged by utilizing the energy of a magnetic field generated when the power transmitting device transmits power.

7. A contactless power supply system comprising: a power receiving device; a power transmitting device that transmits power to the power receiving device in a contactless manner; and a notification device described in any one of claims 1 to 6, wherein when the power suppression signal is received, the power transmitting device executes power transmission by the power transmitting device such that the power transmitted by the power transmitting device is suppressed compared to before the power suppression signal was received.

8. A computer program for controlling a power transmission device included in a contactless power supply system, the contactless power supply system further including a power receiving device to which power is supplied contactlessly by the power transmission device, and a notification device described in any one of claims 1 to 6, the computer program causing a computer possessed by the power transmission device to realize a function of controlling power transmission by the power transmission device when the power reduction signal is received, so that the power transmitted by the power transmission device is reduced compared to before the power reduction signal was received.

9. A power transmission device that transmits power to a power receiving device in a non-contact manner, wherein, when the power suppression signal output by a notification device described in any one of claims 1 to 6 is received, the power transmission device executes power transmission such that the power transmitted by the power transmission device is suppressed compared to before the power suppression signal was received.

10. A power receiving device to which power is transmitted contactlessly by a power transmitting device, wherein when the power transmitting device receives the power suppression signal output by a notification device described in any one of claims 1 to 6, the power transmitting device performs power transmission such that the power transmitted by the power transmitting device is suppressed compared to before the power suppression signal was received.

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