Power transmission apparatus and non-contact power supply system

Abstract

A power transmission apparatus (10) comprising an extending power transmission coupler (14, 140), a high-frequency power supply (12) that supplies high-frequency power to the power transmission coupler (14, 140) via a matching circuit (13), object detection sensors (3a, 3b) that are respectively installed at one end and the other end of the power transmission coupler (14, 140) and that detect power reception devices passing through the respective installed positions, and a control device (15) that controls the matching circuit (13), wherein the matching circuit (13) is configured with a circuit that can be switched to a plurality of circuit configurations, and the control device (15) receives signals from the respective object detection sensors (3a, 3b), analyzes the received signals, determines the number of power reception devices (20) positioned on the power transmission coupler (14, 140), and then performs control so as to switch the circuit configuration of the matching circuit (13) on the basis of the determined number of power reception devices (20).

Description

Power transmission device and wireless power supply system

[0001] The present application relates to a power transmitting device and a contactless power supply system.

[0002] Wireless power transfer, which wirelessly supplies high-frequency power generated by a high-frequency power source to multiple power receiving devices without contact, has been attracting attention. In wireless power transfer, the impedance to the high-frequency power source changes depending on the number of power receiving devices being powered, resulting in a decrease in power conversion efficiency or power transmission efficiency. One technology to address this issue is to match the impedance with the high-frequency power source by switching between multiple matching circuits using reflected waves from a power transmitting electrode.

[0003] For example, Patent Document 1 proposes a wireless power supply technology in which a reflected wave from an electric field coupling power transmission electrode is used to switch between a plurality of matching circuits, thereby matching impedance with a high frequency power source.

[0004] JP 2019-97297 A

[0005] Patent Document 1 describes a method in which a detection circuit is inserted between a matching circuit and a high-frequency power source, and the detection of reflections from the power transmitting electrode determines whether or not a match is achieved, and then switches the matching circuit. However, the method of detecting reflected waves from the power transmitting electrode does not allow accurate determination of the number of power receiving devices to which power is supplied, and therefore switching to an appropriate matching circuit cannot be performed in a single switch, and the matching circuit must be switched multiple times until an appropriate matching circuit is switched, resulting in a problem of poor responsiveness in switching the matching circuit.

[0006] The present invention aims to provide a device that can perform impedance matching by switching the matching circuit once and has good switching response.

[0007] The power transmission device disclosed in the present application is a power transmission device comprising an extending power transmission coupler, a high-frequency power source that supplies high-frequency power to the power transmission coupler via a matching circuit, object detection sensors installed at one end and the other end of the power transmission coupler and that detect power receiving devices passing through the installed positions, and a control device that controls the matching circuit, wherein the matching circuit is composed of a circuit that can be switched between multiple circuit configurations, and the control device receives signals from each of the object detection sensors, analyzes the received signals, determines the number of power receiving devices located on the power transmission coupler, and controls the matching circuit to switch its circuit configuration based on the determined number of power receiving devices.

[0008] According to the present invention, it is possible to provide a device that can perform impedance matching by switching the matching circuit once and has good switching response.

[0009] FIG. 1 is a schematic block diagram showing a configuration of a contactless power supply system according to embodiment 1. FIG. 2 is a block diagram showing a configuration of a power receiving device included in the contactless power supply system according to embodiment 1. FIG. 3 is a circuit diagram showing an example of the configuration of a matching circuit of a power transmitting device included in the contactless power supply system according to embodiment 1. FIG. 4 is a circuit diagram showing another example of the configuration of the matching circuit of a power transmitting device included in the contactless power supply system according to embodiment 1. FIG. 5 is a circuit diagram showing yet another example of the configuration of the matching circuit of a power transmitting device included in the contactless power supply system according to embodiment 1. FIG. 6 is a circuit diagram showing yet another example of the configuration of the matching circuit of a power transmitting device included in the contactless power supply system according to embodiment 1. FIG. 7 is a circuit diagram showing an example of the configuration of a matching circuit of a power transmitting device included in the contactless power supply system according to embodiment 2. FIG. 8 is a schematic block diagram showing a configuration of a contactless power supply system according to embodiment 3. FIG. 9 is a schematic block diagram showing a configuration of a contactless power supply system according to embodiment 4. FIG. 10 is a schematic block diagram showing another configuration of the contactless power supply system according to embodiment 4. FIG. 11 is a block diagram showing an example of the configuration of a control device of the present application.

[0010] Embodiment 1. FIG. 1 is a schematic block diagram showing the configuration of a contactless power transfer system according to embodiment 1. The contactless power transfer system shown in FIG. 1 includes a power receiving device and a power transmitting device for supplying power to the power receiving device. The power transmitting device 10 includes a DC power source 11, a high-frequency power source 12 that converts DC power into high-frequency AC power, a matching circuit 13, two parallel power transmitting electrodes 141 and 142 (collectively referred to as a power transmitting coupler 14 or a power transmitting electrode pair 14) that extend in the direction of movement of the power receiving device, an object detection sensor 3a disposed at the entrance and an object detection sensor 3b disposed at the exit of the power transmitting electrode pair 14 that detect the passage of the power receiving device, a control device 15 that controls the matching circuit 13, the DC power source 11, the high-frequency power source 12, and the like. FIG. 1 illustrates two power receiving devices: a power receiving device 20a and a power receiving device 20b. When the power receiving devices are not distinguished from each other, they may be referred to as power receiving devices 20.

[0011] The DC power supply 11 includes a switching circuit such as a DC-DC converter, converts the voltage of DC power input from an external source, and outputs the converted DC power. The voltage output from the DC power supply 11 is determined by the ON / OFF operation of switch elements in the switching circuit. The high-frequency power supply 12 includes, for example, a bridge-configured inverter or a class E inverter, converts the DC power output from the DC power supply 11 into AC power, and outputs the converted AC power. The high-frequency power supply 12 is a power supply that outputs a high-frequency voltage or a high-frequency current, and the output waveform may be a waveform including multiple frequency components, such as a rectangular waveform.

[0012] The matching circuit 13 includes a circuit configuration that can be switched between a plurality of different circuit configurations, and receives high-frequency AC power output from the high-frequency power supply 12 to generate a resonant voltage in the power transmitting electrode pair 14. The number of switchable circuit configurations of the matching circuit 13 is preferably equal to or greater than the maximum number of power receiving devices 20 that are located on the power transmitting electrode pair 14 and that may simultaneously supply power. Fig. 1 shows a state in which two power receiving devices 20, a power receiving device 20a and a power receiving device 20b, are located on the power transmitting electrode pair 14. Details of the matching circuit 13 will be described later.

[0013] FIG. 1 illustrates two power receiving devices 20: a power receiving device 20a having power receiving electrodes 20a1 and 20a2, and a power receiving device 20b having power receiving electrodes 20b1 and 20b2. As shown in FIG. 2 , the power receiving device 20a includes, for example, power receiving electrodes 20a1 and 20a2, a power receiving circuit 201, a rectifier circuit 202, and a filter 203, and supplies power to a load 204. The power receiving device 20b has a similar configuration. When a voltage is applied to the power transmitting electrode pair 14 of the power transmitting device, AC power is transmitted between the power transmitting electrode pair 14 and the power receiving electrode by capacitive coupling. While FIG. 1 illustrates an example in which there are two power receiving devices 20, the number of power receiving devices 20 on the power transmitting electrode pair 14 varies, is not limited, and may be zero.

[0014] The power receiving circuit 201 receives AC power transmitted to the power receiving electrode and outputs the AC power to the rectifier circuit 202. The rectifier circuit 202 is configured, for example, with four diode elements connected in a full bridge, and receives the AC power output from the power receiving circuit 201 and outputs DC power, which is used as power for a load 204 in the power receiving device 20 via a filter 203.

[0015] The filter 203 is, for example, a C filter configured with a capacitor, and attenuates high-frequency components contained in the voltage and current output from the rectifier circuit 202. Depending on the system configuration, a different filter configuration may be applied, such as an LC filter configured with a capacitor and a reactor. A load 204 is connected to the filter 203. The load 204 is, for example, a motor that consumes power or a battery for storing power. The load configuration may also include a power converter for adjusting the load voltage.

[0016] 3 is a circuit diagram showing an example of the configuration of the matching circuit 13 included in the power transmitting device 10 according to embodiment 1. The matching circuit 13 has a circuit configuration that can be switched between N circuit configurations, and includes N inductors L11 to L1N, capacitors C11 to C1N, and selector switches SW1 to SWN that switch the circuit configuration. All of the inductors are connected in series to one of the power transmitting electrodes of the power transmitting electrode pair 14, and a series assembly of a capacitor C1K and a selector switch S1K (also referred to as a capacitor-switch series assembly) is connected in parallel to the power transmitting electrode pair 14. That is, the matching circuit is configured such that the terminal connected to one of the power transmitting electrodes is the first output terminal T1, the terminal connected to the other power transmitting electrode is the second output terminal T2, N is an integer greater than or equal to 2, and L is all integers greater than or equal to 1 and N-1 inclusive, the matching circuit includes a series assembly of N inductors connected to the first output terminal T1, and N capacitor-switch series assembly, which are series assembly of capacitors and changeover switches, a first capacitor-switch series assembly of the N capacitor-switch series assembly is connected between the first output terminal T1 and the second output terminal T2, and an (L+1)th capacitor-switch series assembly is connected between the Lth connection point, counting from the first output terminal T1, of the connection point of adjacent inductors of the series assembly of N inductors and the second output terminal T2.

[0017] The circuit configurations are switched as follows. By turning on the selector switch of the first capacitor-switch series arrangement closest to the power transmitting electrode pair 14, i.e., the first selector switch S11, and turning off the other selector switches, a first circuit configuration is formed by the first capacitor C11 and all inductors on the high-frequency power supply side of the first capacitor. By turning on the second selector switch S12 and turning off the other selector switches, a second circuit configuration is formed by the second capacitor C12 and all inductors L12 to L1N connected in series on the high-frequency power supply side of the second capacitor C12. In this way, by turning on the Kth selector switch S1K and turning off the other selector switches, a Kth circuit configuration is formed by the capacitor C1K and all inductors L1K to L1N on the high-frequency power supply side of the Kth capacitor C1K. By turning on the Nth selector switch S1N closest to the high-frequency power supply and turning off the other selector switches, an Nth circuit configuration is formed by the Nth capacitor C1N and inductor L1N. 4, the inductors L11 to L1N may be equally divided, i.e., connected vertically symmetrically as inductors L11 to L1N each having half the inductance value of the inductors L11 to L1N shown in FIG.

[0018] The first circuit configuration corresponds to a case where one power receiving device 20 is located on the power transmitting electrode pair 14, the second circuit configuration corresponds to a case where two power receiving devices are located, and the Kth circuit configuration corresponds to a case where K power receiving devices are located. The capacitance of capacitor C12 is greater than that of capacitor C11, and the capacitance of capacitor C13 is greater than that of capacitor C12. Similarly, the closer a capacitor is to the high-frequency power source and the farther it is from the power transmitting electrode, the greater the capacitance of the capacitor. The inductances of inductors L11 to L1N are each set to satisfy a resonance condition with each of capacitors C11, C12, ..., C1N in all of the first to Nth circuit configurations formed. For example, inductor L1N is designed to satisfy a resonance condition with capacitor C1N, and inductor L1N and inductor L1(N-1) are designed so that the combined inductance of the two inductors satisfies a resonance condition with capacitor C1(N-1). The inductors may be the same or different from each other.

[0019] The object detection sensors 3 a and 3 b may be any sensors capable of detecting the power receiving device 20 passing in front of the sensors. For example, an optical sensor may be used. Alternatively, an electric field may be used to cause a current to flow through the sensor only when the power receiving electrode passes, thereby detecting the passage of the power receiving device. Alternatively, electromagnetic waves or infrared rays may be used.

[0020] The control device 15 controls the selector switches of the matching circuit 13 and the high-frequency power supply 12. When the number of power receiving devices 20 located on the power transmitting electrode pair 14 is one, the first selector switch S11 is turned on, and the other selector switches are turned off. When the number of power receiving devices 20 located on the power transmitting electrode pair 14 is two, the second selector switch S12 is turned on, and the other selector switches are turned off. In this way, when the number of power receiving devices 20 located on the power transmitting electrode pair 14 that transmit power is K, the Kth selector switch S1K is turned on, and the other selector switches are turned off. In other words, the number of power receiving devices 20 corresponds to the position of the selector switch that is turned on, and the greater the number of power receiving devices 20, the closer the selector switch to the high-frequency power supply 12 is turned on.

[0021] The object detection sensor 3a arranged at the entrance of the power transmitting electrode pair 14 and the object detection sensor 3b arranged at the exit send a signal to the control device 15 when they detect the passage of a power receiving device 20. When the control device 15 receives a signal from the object detection sensor 3a, it increments the number of power receiving devices 20 to transmit power to by 1, and when it receives a signal from the object detection sensor 3b, it decrements the number of power receiving devices 20 to transmit power to by 1, thereby determining the number of power receiving devices 20 to transmit power to. If the determined number of power receiving devices 20 is 0, power is not transmitted.

[0022] If there are no power receiving devices 20 on the power transmitting electrode pair 14 before power transmission starts, the number of power receiving devices 20 is set to 0 as an initial value, and no high-frequency power is transmitted to the matching circuit 13. Power transmission starts and the number of power receiving devices 20 is determined only after a signal is sent from the object detection sensor 3 a.

[0023] If there are power receiving devices 20 on the power transmitting electrode pair 14 before the start of power transmission, the initial value is set to the number of power receiving devices 20 on the power transmitting electrode pair 14. The number of power receiving devices 20 on the power transmitting electrode pair 14 before the start of power transmission may be determined by receiving position information from the power receiving devices 20 or from a mobile object to which the power receiving devices 20 are attached, and making a determination from the received position information. After determining the number of power receiving devices 20 on the power transmitting electrode pair 14 before the start of power transmission, the circuit configuration is switched to one corresponding to the number of power receiving devices 20, and power transmission from the high-frequency power source 12 is started.

[0024] As described above, according to the contactless power transmission system of the first embodiment, the control device 15 determines the number of power receiving devices 20 to transmit power to based on signals sent from the object detection sensors 3 a and 3 b, and switches the circuit configuration. This enables highly efficient power transmission even when the number of power receiving devices 20 to transmit power to varies. Furthermore, switching to an appropriate circuit configuration in a single switch improves the responsiveness of the circuit configuration switch.

[0025] The matching circuit 13 may have a circuit configuration as shown in Fig. 5, in which a circuit having only an inductor and a capacitor without a changeover switch is connected to the high-frequency power supply side of the circuit configuration of Fig. 3. Alternatively, a circuit configuration as shown in Fig. 6 may be used in which the inductor and capacitor of the circuit configuration shown in Fig. 3 or Fig. 5 are interchanged.

[0026] Embodiment 2. Fig. 7 is a circuit diagram showing the configuration of a matching circuit of a power transmission device of a contactless power transfer system according to embodiment 2. The basic configuration of the contactless power transfer system in embodiment 2 is the same as that of embodiment 1, but the configuration of matching circuit 13 in power transmission device 10 is different from that of embodiment 1, as shown in Fig. 7, in that a current sensor I1K that detects a current flowing through each changeover switch is connected in series to each changeover switch.

[0027] As in the first embodiment, the control device 15 controls the changeover switches of the matching circuit 13, and when the number of power receiving devices 20 to transmit power is 1, the control device 15 turns on the first changeover switch S11 and turns off the other changeover switches. When the number of power receiving devices 20 to transmit power is 2, the control device 15 turns on the second changeover switch S12 and turns off the other changeover switches. In this way, when the number of power receiving devices 20 to transmit power is K, the control device 15 turns on the Kth changeover switch S1K and turns off the other changeover switches.

[0028] When object detection sensor 3a and object detection sensor 3b detect the passage of power receiving device 20, they send a signal to control device 15. When a signal is sent from object detection sensor 3a, the control device increments the number of power receiving devices to transmit power by 1, and when a signal is sent from object detection sensor 3b, the control device decrements the number of power receiving devices to transmit power by 1, thereby determining the number of power receiving devices to transmit power to. If the determined number of power receiving devices is 0, power is not transmitted.

[0029] The current sensor determines whether the circuit configuration of the matching circuit 13 is switched, and if it detects a current exceeding a preset threshold, it determines that there is continuity, and if it does not detect a current equal to or greater than the threshold, it determines that there is no continuity.

[0030] The control device 15 receives signals from the object detection sensors 3a and 3b and stops the power supply from the high-frequency power source 12 before switching the circuit configuration of the matching circuit 13 to match the number of power receiving devices to which power is being transmitted. Then, the control device 15 turns on the selector switch S1K and turns off the other selector switches so that the circuit configuration corresponds to the number K of power receiving devices to which power is being transmitted. At this time, even after the power supply from the high-frequency power source 12 is stopped, current continues to flow through the matching circuit 13 until the energy stored in the inductors and capacitors of the matching circuit 13 is depleted. This current is used to determine whether the circuit configuration has been switched. After controlling the switching of the circuit configuration, the control device 15 determines that the circuit configuration has been switched over when the current sensor of the circuit configuration before the switching becomes non-conductive and the current sensor of the circuit configuration after the switching becomes conductive, and then controls the resumption of the power supply from the high-frequency power source 12 that was previously stopped. That is, the power supply from the high frequency power supply 12 is controlled to resume when the current value of the changeover switch that turns off the switch to be changed becomes equal to or less than a preset value and when the current value of the changeover switch that turns on the switch to be changed becomes equal to or greater than a preset value.

[0031] As described above, according to the second embodiment, the control device 15 determines the number of power receiving devices to transmit power to based on signals sent from the object detection sensors 3 a and 3 b, and switches the circuit configuration of the matching circuit 13, thereby achieving the same effect as in the first embodiment. An effect not achieved by the first embodiment is that by stopping power transmission when the circuit configuration is switched, it is possible to prevent the operation of the high-frequency power supply 12 from becoming unstable at the timing of the circuit configuration switching. Furthermore, by using a current sensor in the matching circuit 13 to determine the completion of the circuit configuration switching and then resuming power transmission, the period during which power transmission is stopped is minimized, and power can be stably transmitted to the power receiving devices 20 on the power transmitting electrode pairs 14.

[0032] Embodiment 3. Figure 8 is a schematic block diagram showing the configuration of a contactless power transfer system according to embodiment 3. The basic configuration of the contactless power transfer system in embodiment 3 is the same as that of embodiment 1, except that the power transmission device 10 has a power transmission coil 140 as a power transmission coupler instead of a power transmission electrode, and the power receiving device 20 has a power receiving coil 21 (in Figure 8, the power receiving device 20a has a power receiving coil 21a, and the power receiving device 20b has a power receiving coil 21b), and the power transmission device 10 supplies power to the power receiving device 20 by utilizing magnetic coupling between the power transmission coil 140 and the power receiving coil 21. Furthermore, the matching circuit 13 of the power transmission device 10 has two or more different circuit configurations, and the circuit configuration resonates with the power transmission coil. For example, the matching circuit 13 may be configured with a selector switch and a capacitor connected in series with the switch. The power receiving circuit of the power receiving device 20 is a circuit resonates with the power receiving coil. For example, the matching circuit 13 may be configured with a capacitor connected in series or parallel to the power receiving coil.

[0033] In embodiment 3, the power transmission coupler, that is, the power transmission coil 140, has an object detection sensor 3a at the entrance and an object detection sensor 3b at the exit. The object detection sensors 3a and 3b are, for example, devices that optically detect the power receiving device 20 passing in front of the sensors, and can be anything that can determine the passage of the power receiving device 20.

[0034] The control device 15 controls the changeover switches of the matching circuit 13, as in the first embodiment, and turns on the changeover switch for the first circuit configuration when the number of power receiving devices 20 to transmit power is 1, and turns off the other changeover switches. When the number of power receiving devices 20 to transmit power is 2, the control device 15 turns on the changeover switch for the second circuit configuration, and turns off the other changeover switches. In this way, when the number of power receiving devices 20 to transmit power is K, the control device 15 performs control such that the changeover switch for the Kth circuit configuration is turned on, and the other changeover switches are turned off.

[0035] When object detection sensor 3a and object detection sensor 3b detect the passage of a power receiving device 20, they send a signal to control device 15. When a signal is sent from object detection sensor 3a, the control device increments the number of power receiving devices to transmit power by 1, and when a signal is sent from object detection sensor 3b, the control device decrements the number of power receiving devices to transmit power by 1, thereby determining the number of power receiving devices 20 to transmit power to. If the determined number of power receiving devices 20 is 0, power is not transmitted.

[0036] If there are no power receiving devices 20 on the power transmitting coil before power transmission starts, the initial value of the number of power receiving devices 20 to transmit power to is set to 0, and power transmission is not performed. Power transmission starts only when a signal is sent from the object detection sensor 3a at the entrance, and the number of power receiving devices 20 is determined.

[0037] If there are power receiving devices 20 on the power transmitting coil before the start of power transmission, the initial value is set to the number of power receiving devices 20 on the power transmitting coil 140. The number of power receiving devices 20 on the power transmitting coil 140 before the start of power transmission may be determined by receiving position information from the power receiving devices 20 or from a mobile object to which the power receiving devices 20 are attached, and making the determination from the received position information. After determining the number of power receiving devices 20 on the power transmitting coil 140 before the start of power transmission, the matching circuit 13 is switched to a circuit configuration corresponding to the number of power receiving devices 20, and power transmission is started.

[0038] As described above, according to the third embodiment, the control device 15 determines the number of power receiving devices 20 to which power is to be transmitted based on signals sent from the object detection sensors 3 a and 3 b, and switches the circuit configuration of the matching circuit 13. This enables highly efficient power transmission even when the number of power receiving devices 20 to which power is to be transmitted varies, as in the first embodiment. Furthermore, by switching to an appropriate circuit configuration in a single switching operation, the responsiveness of the switching of the circuit configuration of the matching circuit 13 is improved.

[0039] Fourth Embodiment. Figure 9 is a schematic block diagram showing the configuration of a contactless power transfer system according to a fourth embodiment. The contactless power transfer system according to the fourth embodiment has a plurality of power transmission couplers arranged side by side, and supplies power to a power receiving device on each power transmission coupler. Figure 9 shows an example in which three power transmission couplers 14a, 14b, and 14c are arranged side by side, with power receiving devices 20a and 20b on power transmission coupler 14a, power receiving device 20c on power transmission coupler 14b, and power receiving device 20d on power transmission coupler 14c. Each power transmission coupler is configured to receive high-frequency power from the matching circuit shown in Figure 1 or Figure 8. That is, a single power transmission device is configured by a high-frequency power source, a DC power source, a control device, and a power transmission coupler. The control devices shown in Figures 1 and 8 may be provided for each power transmission device. Alternatively, a single control device may be provided to transmit control signals to each power transmission device in a contactless power transfer system having a plurality of power transmission couplers, as shown in Figure 10. A power transmission device including a power transmission coupler 14a is referred to as a power transmission device 10a, a power transmission device including a power transmission coupler 14b is referred to as a power transmission device 10b, and a power transmission device including a power transmission coupler 14c is referred to as a power transmission device 10c. When the individual power transmission devices are not distinguished, they may be referred to as a power transmission device 10 and a power transmission coupler 14. When the individual power receiving devices are not distinguished, they may be referred to as a power receiving device 20. The power transmission device 10a includes a power transmission coupler 14a, a DC power supply 11a, a high-frequency power supply 12a, and a matching circuit 13a. The power transmission device 10b includes a power transmission coupler 14b, a DC power supply 11b, a high-frequency power supply 12b, and a matching circuit 13b. The power transmission device 10c includes a power transmission coupler 14c, a DC power supply 11c, a high-frequency power supply 12c, and a matching circuit 13c. In the configuration of FIG. 9, the power transmission device 10a further includes a control device 15a, the power transmission device 10b further includes a control device 15b, and the power transmission device 10c further includes a control device 15c.

[0040] 9 and 10 illustrate an example in which there are three power transmission couplers 14 and four power receiving devices 20. However, the number of power transmission couplers 14 may be any number, and the number of power receiving devices 20 may be zero. Regarding the object detection sensors described in the first to third embodiments, only one object detection sensor is disposed between adjacent power transmission couplers. That is, the signal output from object detection sensor 3ab shown in FIGS. 9 and 10 is a signal from an object detection sensor disposed at an exit for power transmission device 10a, and a signal from an object detection sensor disposed at an entrance for power transmission device 10b. Similarly, the signal output from object detection sensor 3bc is a signal from an object detection sensor disposed at an exit for power transmission coupler 14b, and a signal from an object detection sensor disposed at an entrance for power transmission coupler 14c. Object detection sensor 3a is an object detection sensor disposed at an entrance for power transmission coupler 14a, and object detection sensor 3c is an object detection sensor disposed at an exit for power transmission coupler 14c. The power transmission couplers 14a, 14b, and 14c may be either the power transmission electrode pair described in embodiment 1 or the power transmission coil described in embodiment 3, and the power receiving device 20 may be any power receiving device compatible with the power transmission couplers.

[0041] The configuration of the power transmission device 10 in the contactless power transfer system according to the fourth embodiment may be any of the configurations of the power transmission devices described in the first to third embodiments. Object detection sensors that determine the passage of the power receiving device 20 are disposed only at the entrance and exit of the arranged power transmission couplers and between each power transmission coupler. When each power transmission device is provided with a control device, as in the configuration shown in FIG. 9 , the power transmission device receives signals from the object detection sensors adjacent to the power transmission coupler included in the power transmission device. For example, the power transmission coupler 14a receives signals determining the passage of the power receiving device 20 from two sensors: the object detection sensor 3a and the object detection sensor 3ab that outputs a signal as an object detection sensor disposed at the exit of the power transmission coupler 14a. The control device of each power transmission device determines the number of power receiving devices to which power is to be transmitted by incrementing the number of power receiving devices to which power is to be transmitted by 1 when a signal is received from an object detection sensor disposed in front of the power transmission device in the direction of travel of the power receiving device, and by decrementing the number of power receiving devices to which power is to be transmitted by 1 when a signal is received from an object detection sensor disposed behind the power transmission device in the direction of travel of the power receiving device. If the number of power receiving devices to which power is to be transmitted is determined to be 0, power transmission is not performed.

[0042] Similarly to the first embodiment, the control device controls the changeover switches of the matching circuits, and when the number of power receiving devices 20 that transmit power is 1, the changeover switch for the first circuit configuration is turned on, and the other changeover switches are turned off. When the number of power receiving devices 20 that transmit power is 2, the changeover switch for the second circuit configuration is turned on, and the other changeover switches are turned off. In this way, when the number of power receiving devices 20 that transmit power is K, the changeover switch for the Kth circuit configuration is turned on, and the other changeover switches are turned off.

[0043] If there are no power receiving devices 20 on the power transmitting coil before power transmission starts, the initial value of the number of power receiving devices 20 to transmit power to is set to 0, and power transmission is not performed. Power transmission starts and the number of power receiving devices 20 is determined only after a signal is sent from the object detection sensor arranged at the entrance of the power transmitting coupler 14.

[0044] The above has described a case where each power transmission device is provided with a control device, as in the configuration of Figure 9. However, in a case where a single control device 150 is provided in a contactless power supply system including multiple power transmission couplers as shown in Figure 10, the control device 150 receives signals from each object detection sensor, determines the number of power receiving devices to which each power transmission device transmits power, and controls switching of the circuit configuration for the matching circuit of each power transmission device according to the number of power receiving devices.

[0045] As described above, according to the fourth embodiment, the control device determines the number of power receiving devices to which the power transmitting device including the power transmitting coupler transmits power based on signals sent from each object detection sensor located adjacent to the power transmitting coupler on the traffic line of the power receiving devices, and controls the switching of the circuit configuration of the matching circuit, thereby achieving the same effect as that of the first embodiment in all the power transmitting devices that make up this system.

[0046] 1, 8, 9, and 10 specifically include a central processing unit (CPU) or other processing device 15p, a storage device 15m that exchanges data with the processing device 15p, and an input / output interface 15i that inputs and outputs signals between the processing device 15p and the outside, as shown in FIG. 11. The processing device 15p may include an application-specific integrated circuit (ASIC), an integrated circuit (IC), a digital signal processor (DSP), a field programmable gate array (FPGA), and various signal processing circuits. Furthermore, multiple processing devices of the same or different types may be provided, and each processing may be shared and executed. The storage device 15m may include a random access memory (RAM) that can read and write data from the processing device 15p, a read-only memory (ROM) that can read data from the processing device 15p, and the like. The input / output interface 15i is composed of, for example, an A / D converter that inputs sensor signals output from an object detection sensor, a current sensor, etc. to the arithmetic processing unit 15p, and an A / D converter that outputs control signals to each matching circuit and each high-frequency power supply, etc.

[0047] Although various exemplary embodiments and examples are described in this application, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless modifications not illustrated are contemplated within the scope of the technology disclosed in this specification. For example, this includes cases where at least one component is modified, added, or omitted, and even cases where at least one component is extracted and combined with components of another embodiment.

[0048] 10, 10a, 10b, 10c Power transmitting device, 12, 12a, 12b, 12c High frequency power source, 13, 13a, 13b, 13c Matching circuit, 14, 14a, 14b, 14c, 140 Power transmitting coupler, 141, 142 Power transmitting electrode, 15, 150 Control device, 20, 20a, 20b, 20c, 20d Power receiving device, 3a, 3b, 3c, 3ab, 3bc Object detection sensor, C11 to C14 Capacitor, I11 to I14 Current sensor, L11 to L14 Inductor, S11 to S14 Changeover switch

Claims

1. A power transmission device including an extending power transmission coupler, a high frequency power source that supplies high frequency power to the power transmission coupler via a matching circuit, object detection sensors that are installed at one end and the other end of the power transmission coupler and that detect a power receiving device passing through the installed positions, and a control device that controls the matching circuit, The matching circuit is composed of a circuit that can be switched between multiple circuit configurations, and the control device receives signals from each of the object detection sensors, analyzes the received signals, determines the number of power receiving devices located on the power transmitting coupler, and controls the power transmitting device to switch the circuit configuration of the matching circuit based on the determined number of power receiving devices.

2. The power transmitting device according to claim 1 , wherein the power transmitting coupler is a power transmitting electrode pair formed of two power transmitting electrodes extending in parallel.

3. The power transmitting device according to claim 1 , wherein the power transmitting coupler is configured by a coil extending in an extension direction.

4. The power transmitting device according to claim 1 , wherein the matching circuit is a circuit including a plurality of inductances, a plurality of capacitors, and a plurality of change-over switches.

5. the matching circuit is a terminal connected to one of the power transmitting electrodes as a first output terminal, and a terminal connected to the other power transmitting electrode as a second output terminal, where N is an integer greater than or equal to 2 and L is an integer greater than or equal to 1 and N-1 inclusive, and includes a series body of N inductors connected to the first output terminal, a series body of N inductors connected to the second output terminal, and N capacitor-switch series bodies each being a series body of a capacitor and a changeover switch, wherein a first capacitor-switch series body among the N capacitor-switch series bodies is connected between the first output terminal and the second output terminal, and an L+1-th capacitor-switch series body among the N capacitor-switch series bodies is connected between the second output terminal and an L-th connection point, counting from the first output terminal, of a connection point of adjacent inductors of the series body of N inductors connected to the first output terminal.

6. the matching circuit is a terminal connected to one of the power transmitting electrodes as a first output terminal, and a terminal connected to the other power transmitting electrode as a second output terminal, where N is an integer greater than or equal to 2 and L is an integer greater than or equal to 1 and N-1 inclusive, and includes a series body of N inductors connected to the first output terminal, a series body of N inductors connected to the second output terminal, and N capacitor-switch series bodies each being a series body of a capacitor and a changeover switch, wherein a first capacitor-switch series body among the N capacitor-switch series bodies is connected between the first output terminal and the second output terminal, and an L+1 capacitor-switch series body is connected between an L-th connection point, counting from the first output terminal, of a connection point of adjacent inductors of the series body of N inductors connected to the first output terminal, and an L-th connection point, counting from the second output terminal, of a connection point of adjacent inductors of the series body of N inductors connected to the second output terminal.

7. 7. The power transmitting device according to claim 5, wherein the capacitance of each of the capacitors in the N capacitor-switch series bodies increases as the connection position thereof becomes farther from the power transmitting electrode.

8. The power transmitting device described in claim 5 or 6, wherein when the determined number of power receiving devices is K, the control device turns on the changeover switch of the Kth capacitor-switch series body among the N capacitor-switch series bodies of the matching circuit and turns off the other changeover switches.

9. 7. The power transmitting device according to claim 4, further comprising a current sensor for detecting a current flowing through each of the plurality of changeover switches, wherein when switching the circuit configuration of the matching circuit, the control device stops the power supply from the high-frequency power source and transmits a changeover command to the changeover switch to be changed over, and controls so as to resume the power supply from the high-frequency power source when a current value of the changeover switch that turns off the switch to be changed over becomes equal to or less than a preset value and when a current value of the changeover switch that turns on the switch becomes equal to or greater than a preset value.

10. 7. A contactless power transfer system comprising: the power transmitting device according to claim 1; and power receiving devices that move on the power transmitting coupler, wherein the control device determines the number of power receiving devices located on the power transmitting coupler and controls the matching circuit to switch its configuration in accordance with the determined number of power receiving devices.

11. 7. A contactless power supply system comprising a plurality of power transmission devices according to claim 1, wherein the power transmission couplers of the plurality of power transmission devices are arranged side by side in a direction in which they extend, and one of the object detection sensors is arranged between adjacent power transmission couplers.

12. The contactless power supply system according to claim 11 , wherein the control devices of the plurality of power transmission devices are configured as a single control device in the contactless power supply system.