Wireless power transmission system

Abstract

To provide a transmission device of a wireless transmission system capable of improving a transmission efficiency when a plurality of transmission coils are used compared with the conventional art.SOLUTION: A transmission device 2 in a wireless transmission system 1 performing a wireless transmission between transmission coils 11, 12, and 13 and a power reception coil 20 has an inverter circuit 40 connected to the plurality of transmission coils 11, 12, and 13, and a predetermined power source 30, and supplying power to each of the transmission coils 11, 12, and 13. The inverter circuit 40 has a plurality of legs 41, 42, and 43 provided for each of the transmission coils 11, 12 and 13 and connected in parallel.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power transmission device of a wireless power transmission system that transmits power wirelessly between a power transmission coil and a power receiving coil. [Background technology]

[0002] There is known a wireless power transmission system in which multiple power transmission coils are arranged side by side on the same plane and power is transmitted wirelessly without precise position control of the power receiving coil (see, for example, Patent Document 1). The wireless power transmission device described in Patent Document 1 includes a transmitting antenna including a series resonant capacitor and multiple switchable transmitting coils, an inverter whose output side is connected to the transmitting antenna, and a controller that controls the inverter, and the controller determines one power transmission coil to be used for power transmission based on predetermined conditions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-78754 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the wireless power transmission system described in Patent Document 1, since only one power transmitting coil is used for power transmission, power transmission efficiency decreases depending on the position of the power receiving coil. For example, when power transmitting coils are arranged in an array, if a power receiving coil is located above a joint between the power transmitting coils, power transmission efficiency decreases significantly.

[0005] The present invention has been made in consideration of the above circumstances, and its purpose is to provide a power transmission device for a wireless power transmission system that can improve power transmission efficiency compared to conventional devices when multiple power transmission coils are used. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides: A power transmission device in a wireless power transmission system that transmits power wirelessly between a power transmitting coil and a power receiving coil, A plurality of the power transmitting coils; A power transmission device of a wireless power transmission system is provided, which is connected to a predetermined power source, has a plurality of legs provided for each of the power transmission coils and connected in parallel to each other, and an inverter circuit which supplies power to each of the power transmission coils.

[0007] The power transmitting device of the wireless power transmitting system preferably includes a power factor compensation circuit that forms a resonant circuit together with each of the power transmitting coils.

[0008] In the power transmission device of the wireless power transmission system, one end of each of the power transmission coils is connected to each other, a connection portion on one end side of each of the power transmission coils is connected to a portion of the inverter circuit that has a predetermined voltage; It is preferable that the power factor compensation circuit includes an inductor or a capacitor interposed between a connection portion on one end side of each of the power transmission coils and the portion of the inverter circuit at the predetermined voltage, and whose inductance or capacitance is set based on the mutual inductance between the power transmission coils.

[0009] In the power transmission device of the above-mentioned wireless power transmission system, it is preferable that the power factor compensation circuit includes a capacitor provided for each of the power transmission coils, the capacitance of which is set based on the self-inductance of each of the power transmission coils and the mutual inductance between the power transmission coils.

[0010] The power transmitting device of the wireless power transmitting system preferably includes a mutual inductance compensation circuit that adjusts the mutual inductance based on a difference in mutual inductance between the power transmitting coils.

[0011] In the power transmission device of the wireless power transmission system, one end of each of the power transmission coils is connected to each other, a connection portion on one end side of each of the power transmission coils is connected to a portion of the inverter circuit that has a predetermined voltage; It is preferable that the power factor compensation circuit is interposed between the connection portion on one end side of each of the power transmission coils and the portion of the inverter circuit at the predetermined voltage, and that the inductance or capacitance is set based on the mutual inductance between each of the power transmission coils adjusted by the mutual inductance compensation circuit.

[0012] In the power transmission device of the wireless power transmission system, It is preferable that the power factor compensation circuit includes a capacitor provided for each of the power transmission coils, the capacitance of which is set based on the self-inductance of each of the power transmission coils, the self-inductance of the mutual inductance compensation circuit, and the mutual inductance between each of the power transmission coils adjusted by the mutual inductance compensation circuit.

[0013] The power transmission device of the wireless power transmission system a control unit that controls switching elements of the legs of the inverter circuit, It is preferable that the control unit controls the currents of the power transmitting coils so that a ratio of the currents of the power transmitting coils is equal to a ratio of mutual inductances between the power transmitting coils and the power receiving coil.

[0014] In addition, in the present invention, A power transmission device in a wireless power transmission system that transmits power wirelessly between a power transmitting coil and a power receiving coil, a plurality of the power transmitting coils assigned to any of a plurality of power transmitting groups; an inverter circuit connected to a predetermined power source, having a plurality of legs provided for each of the power transmission groups and connected in parallel to each other, and supplying power to each of the power transmission groups; A power transmission device of a wireless power transmission system is provided, which includes a switching circuit that switches the power supply destination so that the power from the inverter circuit is supplied to one of the power transmission coils selected from each of the power transmission groups. [Effects of the Invention]

[0015] According to the power transmission device of the wireless power transmission system of the present invention, when a plurality of power transmission coils are used, power transmission efficiency can be improved compared to conventional methods. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a circuit diagram of a power transmitting device and a power receiving device of a wireless power transmitting system according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a plan view illustrating a power transmitting coil and a power receiving coil. [Figure 3] FIG. 10 is an explanatory diagram showing the switching timing of each leg. [Figure 4] FIG. 10 is an explanatory plan view of a power transmission coil and a power receiving coil according to a second embodiment of the present invention. [Figure 5] 1 is a circuit diagram of a power transmitting device and a power receiving device of a wireless power transmission system. [Figure 6] FIG. 10 is an explanatory plan view of a power transmission coil showing a third embodiment of the present invention. [Figure 7] 1 is a circuit diagram of a power transmitting device and a power receiving device of a wireless power transmission system. [Figure 8] FIG. 10 is an explanatory plan view of a power transmission coil showing a fourth embodiment of the present invention. [Figure 9] 1 is a circuit diagram of a power transmitting device and a power receiving device of a wireless power transmission system. [Figure 10] FIG. 10 is an explanatory plan view of a power transmitting coil and a power receiving coil according to a fifth embodiment of the present invention. [Figure 11] FIG. 2 is a circuit diagram of a power transmission device in a wireless power transmission system. [Figure 12] FIG. 10 is an explanatory plan view of a power transmission coil according to a sixth embodiment of the present invention. [Figure 13]FIG. 2 is a circuit diagram of a power transmission device in a wireless power transmission system. [Figure 14] FIG. 13 is an explanatory plan view of a power transmission coil according to a seventh embodiment of the present invention. [Figure 15] FIG. 2 is a circuit diagram of a power transmission device in a wireless power transmission system. [Figure 16] FIG. 10 is a circuit diagram of a power transmission device showing a modified example. [Figure 17] FIG. 10 is a circuit diagram of a power transmission device showing a modified example. [Figure 18] FIG. 10 is a circuit diagram of a power transmission device showing a modified example. [Figure 19] FIG. 10 is a circuit diagram of a power transmission device showing a modified example. [Figure 20] FIG. 10 is a circuit diagram of a power transmission device showing a modified example. [Figure 21] FIG. 10 is a circuit diagram of a power receiving device showing a modified example. [Figure 22] FIG. 10 is a circuit diagram of a power receiving device showing a modified example. [Figure 23] FIG. 10 is a circuit diagram of a power transmission device showing a comparative example. [Figure 24] 10 is a simulation result showing the power transmission efficiency of an example and a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0017] Figures 1 to 3 show a first embodiment of the present invention, where Figure 1 is a circuit diagram of a wireless power transmission system, Figure 2 is a plan view of a power transmission coil and a power receiving coil, and Figure 3 is an explanatory diagram showing the switching of each leg.

[0018] As shown in Fig. 1, this wireless power transmission system 1 includes a power transmission device 2 having a plurality of power transmission coils 11, 12, and 13, and a power receiving device 3 having a power receiving coil 20 that transmits power wirelessly to each of the power transmission coils 11, 12, and 13. In this embodiment, as shown in Fig. 2, three power transmission coils 11, 12, and 13 that are circular in plan view and have a predetermined thickness are arranged adjacent to each other on the same plane so as not to overlap each other. In this embodiment, the three power transmission coils 11, 12, and 13 are identical. The power transmission device 2 and the power receiving device 3 are movable relative to each other, and wireless power transmission is possible when the power receiving coil 20 is close to each of the power transmission coils 11, 12, and 13.

[0019] As shown in FIG. 1 , the power transmitting device 2 includes an inverter circuit 40 connected to a DC power supply 30 and supplying power to each of the power transmitting coils 11, 12, and 13. The inverter circuit 40 has multiple legs 41, 42, and 43 connected in parallel to each other, each of which is provided between a positive bus and a negative bus for each of the power transmitting coils 11, 12, and 13. In this embodiment, since there are three power transmitting coils 11, 12, and 13, there are also three legs 41, 42, and 43 corresponding to the three power transmitting coils. Each of the legs 41, 42, and 43 includes a positive-side switching element 41a, 42a, and 43a connected to the positive side of the DC power supply 30 and a negative-side switching element 41b, 42b, and 43b connected to the negative side, which are connected in series. For example, a transistor such as an IGBT, a MOSFET, or a HEMT can be used as each of the switching elements 41a, 41b, 42a, 42b, 43a, and 43b. Positive-side nodes 41c, 42c, 43c connected to the other ends of the power transmission coils 11, 12, 13 are provided between the positive-side switching elements 41a, 42a, 43a and the negative-side switching elements 41b, 42b, 43b.

[0020] The inverter circuit 40 also has a positive-side capacitor 51 and a negative-side capacitor 52 connected in series between the positive and negative buses. The positive-side capacitor 51 and the negative-side capacitor 52 equally divide the input voltage from the DC power supply 30. In other words, when the input voltage of the DC power supply 30 is E, the voltage between the positive-side capacitor 51 and the negative-side capacitor 52 is designed to be E / 2. A negative-side node 53 is provided between the positive-side capacitor 51 and the negative-side capacitor 52, and is connected to one end of each of the power transmitting coils 11, 12, and 13.

[0021] As shown in Fig. 1, one ends of the power transmitting coils 11, 12, and 13 are connected to each other. In this embodiment, a so-called Y connection is used, and a connection node 14 is set at one end of each of the power transmitting coils 11, 12, and 13. In this manner, one end of each of the power transmitting coils 11, 12, and 13 is connected to an intermediate voltage of the input voltage of the DC power supply 30 via an inductor 60 in a wired state. The other ends of each of the power transmitting coils 11, 12, and 13 are connected to the legs 41, 42, and 43 via resonant capacitors 61, 62, and 63, respectively. In this embodiment, the inductor 60 and the resonant capacitors 61, 62, and 63, together with the power transmitting coils 11, 12, and 13, form a power factor compensation circuit 70 that forms a resonant circuit.

[0022] The inductance of the inductor 60 is set based on the mutual inductance between the power transmitting coils 11, 12, and 13. The capacitance of each of the resonant capacitors 61, 62, and 63 is set taking into consideration the self-inductance of each of the power transmitting coils 11, 12, and 13 and the mutual inductance between each of the power transmitting coils 11, 12, and 13.

[0023] Specifically, in this embodiment, the self-inductances of the power transmitting coils 11, 12, and 13 are equal to each other, and the mutual inductances between the power transmitting coils 11, 12, and 13 are also equal to each other. However, since the power transmitting coils 11, 12, and 13 weaken each other's magnetic fields when currents flow in the same direction, the mutual inductance value is negative. Let ω be the operating angular frequency of the device, and L be the self-inductance of each of the power transmitting coils 11, 12, and 13. t, the mutual inductance between the transmitting coils 11, 12, and 13 is -M t (M t >0), the capacitance C of each resonant capacitor 61, 62, 63 t and the inductance L0 of the inductor 60 is C t =1 / (ω 2 (L t +M t )) L0=M t It is set as follows.

[0024] As shown in FIG. 1, the power receiving device 3 has a resonant capacitor 21 and a load resistor 22 connected in series with the power receiving coil 20. The load resistor 22 is supplied with power transmitted from the power transmitting device 2. In the power receiving device 3, the resonant capacitor 21 forms a power factor compensation circuit on the power receiving side. The self-inductance of the power receiving coil 20 is set to L r When this is done, the capacitance C of the resonant capacitor 21 is r teeth, C r =1 / (ω 2 L r ) It is set as follows.

[0025] The power transmitting device 2 also includes a control unit 80 that controls the switching operations of the switching elements 41a, 41b, 42a, 42b, 43a, and 43b. t1r ,M t2r ,M t3r , the currents in the first to third power transmitting coils 11, 12, and 13 are I t1 ,I t2 ,I t3 When this is the case, the control unit 80 M t1r :M t2r :M t3r =I t1 :I t2 :I t3 Here, when the winding resistance of each of the power transmitting coils 11, 12, and 13 can be ignored, the ratio of the phase voltages output by the inverter circuit 40 is determined by the mutual inductance M between each of the power transmitting coils 11, 12, and 13 and the power receiving coil 20. t1r ,M t2r ,M t3r In this case, the control unit 80 may control the ratio of the currents in the power transmission coils 11, 12, and 13 in accordance with the ratio of the output voltages of the inverter circuits 40. As shown in FIG. 3, the control unit 80 controls the ratio of the mutual inductance M t1r ,M t2r ,M t3r When the voltage is negative, the current phase is shifted by 180° (π) relative to the positive voltage.

[0026] According to the power transmitter 2 of the wireless power transmission system 1 configured as described above, current flows to each of the power transmission coils 11, 12, and 13 during wireless power transmission, which improves power transmission efficiency compared to conventional systems in which current is passed through a single selected power transmission coil. In particular, when the power receiving coil 20 is located in a gap between the power transmission coils 11, 12, and 13, the power transmission efficiency is significantly improved.

[0027] Furthermore, the control unit 80 controls the currents in the power transmitting coils 11, 12, and 13 so that the ratio of the currents in the power transmitting coils 11, 12, and 13 matches the ratio of the mutual inductance between the power transmitting coils 11, 12, and 13 and the power receiving coil 20, thereby achieving extremely high power transmission efficiency. Furthermore, because power is supplied to the multiple power transmitting coils 11, 12, and 13 by one inverter circuit 40, there is no need to provide multiple inverter circuits corresponding to the multiple power transmitting coils, and the device can be made smaller.

[0028] Furthermore, one end of each of the power transmission coils 11, 12, and 13 is connected to one another and then connected to a predetermined voltage portion of the power supply voltage 30 via the inductor 60, so that a resonant circuit can be configured corresponding to the mutual inductance between each of the power transmission coils 11, 12, and 13. Furthermore, each of the power transmission coils 11, 12, and 13 is provided with a resonant capacitor 61, 62, and 63, so that a resonant circuit can be configured corresponding to the self-inductance of each of the power transmission coils 11, 12, and 13. In particular, in this embodiment, C t =1 / (ω 2 (L t +M t )) and L0=M t (M t >0), the reactance components due to self-inductance and mutual inductance can be cancelled out.

[0029] 4 and 5 show a second embodiment of the present invention, where FIG. 4 is an explanatory plan view of a power transmitting coil and a power receiving coil, and FIG. 5 is a circuit diagram of a power transmitting device and a power receiving device of a wireless power transmitting system.

[0030] In the wireless power transmission system 101 of this embodiment, as shown in Fig. 4, two power transmission coils 111 and 112, each having a predetermined thickness and a rectangular shape in a plan view, are arranged adjacent to each other on the same plane so as not to overlap each other. In this embodiment, the two power transmission coils 111 and 112 are identical. The power receiving device 103 also has a power receiving coil 120, and a resonant capacitor 121 and a load resistor 122 connected in series with the power receiving coil 120.

[0031] 5, the power transmitting device 102 includes an inverter circuit 140 connected to a DC power supply 130 and supplying power to each of the power transmitting coils 111, 112. The inverter circuit 140 has two legs 141, 142 connected in parallel to each other, provided for each of the power transmitting coils 111, 112, between the positive and negative buses. Positive side nodes 141c, 142c connected to the other ends of the power transmitting coils 111, 112 are set between the positive side switching elements 141a, 142a and the negative side switching elements 141b, 142b connected in series.

[0032] The inverter circuit 140 also has a positive-side capacitor 151 and a negative-side capacitor 152 between the positive and negative buses. The positive-side capacitor 151 and the negative-side capacitor 152 equally divide the input voltage from the DC power supply 130. A negative-side node 153 connected to one end of each of the power transmitting coils 111 and 112 is set between the positive-side capacitor 151 and the negative-side capacitor 152.

[0033] 5, one end of each of the power transmitting coils 111, 112 is connected to each other, and a connection node 114 is set. One end of each of the power transmitting coils 111, 112 is connected in a wired state to an intermediate voltage of the input voltage of the DC power supply 130 via an inductor 160. The other end of each of the power transmitting coils 111, 112 is connected to each of the legs 141, 142 via resonant capacitors 161, 162, respectively. In this embodiment, the inductor 160 and each of the resonant capacitors 161, 162, together with each of the power transmitting coils 111, 112, form a power factor compensation circuit 170 that forms a resonant circuit.

[0034] The inductance of the inductor 160 is set based on the mutual inductance between the power transmitting coils 111 and 112. The capacitance of each of the resonant capacitors 161 and 162 is set based on the self-inductance of each of the power transmitting coils 111 and 112 and the mutual inductance between each of the power transmitting coils 111 and 112.

[0035] In this embodiment, the self-inductances of the power transmitting coils 111 and 112 are equal to each other, and when currents flow in the same direction, they weaken each other's magnetic fields. Therefore, the mutual inductance between the power transmitting coils 111 and 112 is negative. Let ω be the operating angular frequency of the device, and L be the self-inductance of each of the power transmitting coils 111 and 112. t , the mutual inductance between the power transmitting coils 111 and 112 is −M t When this is done, the capacitance C of each resonant capacitor 161, 162 is t and the inductance L0 of the inductor 160 is C t =1 / (ω2 (L t +M t )) L0=M t (M t >0) It is set as follows.

[0036] 5, the power receiving device 103 has a resonance capacitor 121 and a load resistor 122 connected in series with the power receiving coil 120. The self-inductance of the power receiving coil 120 is expressed as L r Then, the capacitance C of the resonant capacitor 121 is r teeth, C r =1 / (ω 2 L r ) It is set as follows.

[0037] The power transmitting device 102 also includes a control unit 180 that controls the switching operations of the switching elements 141a, 141b, 142a, and 142b. t1r ,M t2r , the current in the first and second power transmitting coils 111 and 112 is I t1 ,I t2 When this is the case, the control unit 180 M t1r :M t2r =I t1 :I t2 Here, when the winding resistance of each of the power transmitting coils 111 and 112 can be ignored, the ratio of the phase voltages output by the inverter circuit 140 is determined by the mutual inductance M between each of the power transmitting coils 111 and 112 and the power receiving coil 120. t1r ,M t2r In this case, the control unit 180 may control the ratio of the currents of the power transmitting coils 111 and 112 in accordance with the ratio of the output voltages of the inverter circuits 140.

[0038] According to the power transmitting device 102 of the wireless power transmitting system 101 configured as described above, current flows to each of the power transmitting coils 111, 112 during wireless power transmission, which improves power transmission efficiency compared to conventional systems in which current is passed through a single selected power transmitting coil. In particular, when the power receiving coil 120 is located midway between the power transmitting coils 111, 112, the power transmission efficiency is significantly improved.

[0039] Furthermore, the control unit 180 controls the currents of the power transmitting coils 111, 112 so that the ratio of the currents of the power transmitting coils 111, 112 matches the ratio of the mutual inductances between the power transmitting coils 111, 112 and the power receiving coil 120, thereby achieving extremely high power transmission efficiency. Furthermore, since power is supplied to the multiple power transmitting coils 111, 112 by one inverter circuit 140, there is no need to provide multiple inverter circuits corresponding to the multiple power transmitting coils, and the device can be made smaller.

[0040] Furthermore, one end of each of the power transmitting coils 111, 112 is connected to each other and then connected to a predetermined voltage portion of the power supply voltage 130 via the inductor 160, so that a resonant circuit can be configured corresponding to the mutual inductance between each of the power transmitting coils 111, 112. Furthermore, each of the power transmitting coils 111, 112 is provided with a resonant capacitor 161, 162, so that a resonant circuit can be configured corresponding to the self-inductance of each of the power transmitting coils 111, 112. In this embodiment, C t =1 / (ω 2 (L t +M t )) and L0=M t (M t >0), the reactance components due to self-inductance and mutual inductance can be cancelled out.

[0041] 6 and 7 show a third embodiment of the present invention, where FIG. 6 is an explanatory plan view of a power transmission coil, and FIG. 7 is a circuit diagram of a power transmission device and a power reception device of a wireless power transmission system.

[0042] As shown in Fig. 6, in the wireless power transmission system 201 of this embodiment, the power transmission coils 111, 112 of the second embodiment are arranged so as to partially overlap and mutually strengthen their magnetic fields when currents flow in the same direction. That is, the value of mutual inductance between the power transmission coils 111, 112 is positive. Furthermore, as shown in Fig. 7, the wireless power transmission system 201 of this embodiment has a capacitor 260 instead of the inductor 160 of the second embodiment. The rest of the configuration is the same as that of the second embodiment.

[0043] The capacitance of the capacitor 260 is set based on the mutual inductance between the power transmitting coils 111 and 112. The self-inductance of each of the power transmitting coils 111 and 112 is set by L t , the mutual inductance between the power transmitting coils 111 and 112 is M t When this is done, the capacitance C of each resonant capacitor 161, 162 is t and the capacitance C0 of the capacitor 260 is C t =1 / (ω 2 (L t -M t )) C0=1 / (ω 2 M t ) It is set as follows. The wireless power transmission system 201 configured as above can also achieve the same effects as those of the second embodiment.

[0044] 8 and 9 show a fourth embodiment of the present invention, where FIG. 8 is an explanatory plan view of a power transmission coil, and FIG. 9 is a circuit diagram of a power transmission device and a power reception device of a wireless power transmission system.

[0045] 8, in a wireless power transmission system 301 of the present embodiment, another power transmission coil 113 is arranged adjacent to the adjacent power transmission coils 111, 112 in the arrangement direction of the adjacent power transmission coils 111, 112 of the second embodiment. In the present embodiment, the three power transmission coils 111, 112, 113 are the same. That is, the power transmission device 302 has three power transmission coils 111, 112, 113. In the present embodiment, the mutual inductance between the power transmission coil 111 on one end side and the power transmission coil 112 on the central side, and the mutual inductance between the power transmission coil 112 on the central side and the power transmission coil 113 on the other end side are equal, but the mutual inductance between the power transmission coil 111 on one end side and the power transmission coil 113 on the other end side are different.

[0046] 9, the inverter circuit 340 of the power transmitting device 302 has three legs 141, 142, and 143 provided between the positive and negative buses, one for each of the power transmitting coils 111, 112, and 113. Positive-side nodes 141c, 142c, and 143c connected to the other ends of the power transmitting coils 111, 112, and 113 are established between the positive-side switching elements 141a, 142a, and 143a and the negative-side switching elements 141b, 142b, and 143b connected in series. One ends of the power transmitting coils 111, 112, and 113 are connected to each other, forming a connection node 314. One ends of the power transmitting coils 111, 112, and 113 are connected to an intermediate voltage of the input voltage of the DC power supply 130 via an inductor 360 in a wired state. The other end of each of the power transmitting coils 111, 112, and 113 is connected to each of the legs 141, 142, and 143 via a resonant capacitor 361, 362, and 363. In this embodiment, the inductor 360 and each of the resonant capacitors 361, 362, and 363, together with each of the power transmitting coils 111, 112, and 113, form a power factor compensation circuit 370 that forms a resonant circuit.

[0047] Furthermore, in this embodiment, transformers 391, 392 are interposed between each of the resonant capacitors 361, 362, 363 and each of the legs 141, 142, 143. In this embodiment, two transformers 391, 392 are provided: a transformer 391 corresponding to each of the power transmitting coils 111, 112 on one end side and the center side, and a transformer 392 corresponding to each of the power transmitting coils 112, 113 on the center side and the other end side. The transformers 391, 392 are configured so that the sum of their mutual inductance and the mutual inductance between each of the power transmitting coils 111, 112, 113 is equal to each other. In other words, the transformers 391, 392 form a mutual inductance compensation circuit 390 that adjusts the mutual inductance based on the difference in mutual inductance between each of the power transmitting coils 111, 112, 113. The mutual inductance compensation circuit 390 may also be configured by one transformer corresponding to each of the power transmission coils 111 and 113 on one end side and the other end side.

[0048] In this embodiment, the inductance of the inductor 360 is set based on the adjusted mutual inductance. In addition, since the mutual inductance compensation circuit 390 has a self-inductance, the capacitance C t1 ,C t2 ,C t3 is set taking into consideration the self-inductance of each of the transformers 391 and 392. Specifically, the sum of the self-inductance of each of the power transmitting coils 111, 112, and 113 and the self-inductance of each of the transformers 391 and 392 is L' t1 ,L´ t2 ,L´ t3 ,The mutual inductance between each of the power transmission coils 111, 112, 113 after adjustment is -M t (M t >0), the capacitance C of each resonant capacitor 361, 362, 363 t1 ,C t2 ,C t3 and the inductance L0 of the inductor 360 is C t1 =1 / (ω 2 (L´ t1 +M t )),Ct2 =1 / (ω 2 (L´ t2 +M t )),C t3 =1 / (ω 2 (L´ t3 +M t )) L0=M t It is set as follows.

[0049] Furthermore, the control unit 380 controls the currents of the power transmitting coils 111, 112, and 113 so that the ratio of the currents of the power transmitting coils 111, 112, and 113 matches the ratio of the mutual inductances between the power transmitting coils 111, 112, and 113 and the power receiving coil 120. According to the wireless power transmission system 301 configured as described above, in addition to the effects of the third embodiment, by providing a mutual inductance compensation circuit 390, it is possible to control the power supply to each of the power transmission coils 111, 112, and 113 in the same way as when the mutual inductances between the power transmission coils 111, 112, and 113 are equal to each other.

[0050] 10 and 11 show a fifth embodiment of the present invention, with Fig. 10 being an explanatory plan view of a power transmitting coil and a power receiving coil, and Fig. 11 being a circuit diagram of a power transmitting device in a wireless power transmitting system. Note that the circuit diagram of the power receiving device is omitted in Fig. 11. Note that although the power receiving device, power receiving coil, etc. are not shown in Fig. 11, the power receiving device, power receiving coil, etc. are the same as those in the second embodiment.

[0051] 10 , in the wireless power transmission system of the present embodiment, two more power transmission coils 113 and 114 are provided adjacent to each other in a direction perpendicular to the arrangement direction of the two power transmission coils 111 and 112 of the second embodiment. That is, the power transmission device 402 has four power transmission coils 111, 112, 113, and 114. In the present embodiment, the four power transmission coils 111, 112, 113, and 114 are identical. In the present embodiment, the mutual inductance between the power transmission coils 111, 112, 113, and 114 adjacent to each other in the arrangement direction or a direction perpendicular to the arrangement direction is equal, but is different from the mutual inductance between the power transmission coils 111, 112, 113, and 114 that are not adjacent to each other in either direction.

[0052] 11 , the inverter circuit 440 of the power transmitting device 402 has four legs 141, 142, 143, and 144 provided between the positive and negative buses, one for each of the power transmitting coils 111, 112, 113, and 114. Positive-side nodes 141c, 142c, 143c, and 144c connected to the other ends of the power transmitting coils 111, 112, 113, and 114 are established between the positive-side switching elements 141a, 142a, 143a, and 144a and the negative-side switching elements 141b, 142b, 143b, and 144b connected in series. One ends of the power transmitting coils 111, 112, 113, and 114 are connected to each other, and a connection node 414 is established. One end of each of the power transmitting coils 111, 112, 113, and 114 is connected in a wired state to an intermediate voltage of the input voltage of the DC power supply 130 via an inductor 460. The other end of each of the power transmitting coils 111, 112, 113, and 114 is connected to each of the legs 141, 142, 143, and 144 via resonant capacitors 461, 462, 463, and 464, respectively. In this embodiment, the inductor 460 and each of the resonant capacitors 461, 462, 463, and 464, together with each of the power transmitting coils 111, 112, 113, and 114, form a power factor compensation circuit 470 that forms a resonant circuit.

[0053] Furthermore, in this embodiment, transformers 491 and 492 are interposed between each of the resonant capacitors 461, 462, 463, and 464 and each of the legs 141, 142, 143, and 144. Each of the transformers 491 and 492 is configured so that the sum of its mutual inductance and the mutual inductance between each of the power transmitting coils 111, 112, 113, and 114 is equal to each other. That is, each of the transformers 491 and 492 constitutes a mutual inductance compensation circuit 490 that adjusts the mutual inductance based on the difference in mutual inductance between each of the power transmitting coils 111, 112, 113, and 114. As in the fourth embodiment, the inductance of the inductor 460 is set based on the adjusted mutual inductance, and the capacitance of each of the resonant capacitors 461, 462, 463, and 464 is set taking into account the adjusted self-inductance.

[0054] Furthermore, the control unit 480 controls the currents of the power transmitting coils 111, 112, 113, and 114 so that the ratio of the currents of the power transmitting coils 111, 112, 113, and 114 matches the ratio of the mutual inductances between the power transmitting coils 111, 112, 113, and 114 and the power receiving coil 120. The wireless power transmission system configured as above can also achieve the same effects as those of the fourth embodiment.

[0055] 12 and 13 show a sixth embodiment of the present invention, with Fig. 12 being an explanatory plan view of a power transmitting coil and Fig. 13 being a circuit diagram of a power transmitting device in a wireless power transmitting system. Note that, although Fig. 12 and 13 do not show a power receiving device, a power receiving coil, etc., the power receiving device, the power receiving coil, etc. are the same as those in the first embodiment.

[0056] As shown in Fig. 12, in this wireless power transmitting device 502, a plurality of power transmitting coils 511 to 519 are aligned in a horizontal direction and a diagonal vertical direction on a predetermined plane. In this embodiment, the same power transmitting coils 511 to 519 are used. In this embodiment, the angle between the horizontal direction and the diagonal vertical direction is 60°. As shown in Fig. 13, the power transmitting device 502 includes an inverter circuit 40 having three legs 41, 42, and 43, as in the first embodiment. Each of the power transmitting coils 511 to 519 is assigned to one of three power transmitting groups corresponding to the number of legs 41, 42, and 43.

[0057] 12, the power transmission coils 511 to 519 are arranged in a horizontal direction toward one side (the right in FIG. 12) in the order of power transmission coils belonging to the first power transmission group, power transmission coils belonging to the second power transmission group, and power transmission coils belonging to the third power transmission group. Also, the power transmission coils 511 to 519 are arranged in a diagonal vertical direction toward one side (the upper right in FIG. 12) in the order of power transmission coils belonging to the first power transmission group, power transmission coils belonging to the third power transmission group, and power transmission coils belonging to the second power transmission group.

[0058] 13, each of the legs 41, 42, and 43 of the inverter circuit 40 of the wireless power transmitting device 502 is connected to the other end of each of the power transmitting coils 511-519 via changeover switches 581, 582, and 583. Each of the changeover switches 581, 582, and 583 is provided for each power transmitting group, and selectively supplies power to one of the power transmitting coils 511-519 belonging to each power transmitting group. In this embodiment, each of the changeover switches 581, 582, and 583 forms a switching circuit. The control unit 580 switches each of the changeover switches 581, 582, and 583 based on information related to the power receiving coil. The control unit 580 also controls the currents of each of the power transmitting coils 511-519 so that the ratio of the currents of each of the power transmitting coils 511-519 matches the ratio of the mutual inductance between each of the power transmitting coils 511-519 and the power receiving coil.

[0059] One end of each of the power transmitting coils 511-519 is connected to one another and connected to an intermediate voltage of the input voltage of the DC power supply 30 via an inductor 560. Selector switches 581, 582, and 583 selectively connected to the other end of each of the power transmitting coils 511-519 are connected to each of the legs 41, 42, and 43 via resonant capacitors 561, 562, and 563, respectively. In this embodiment, the inductor 560 and the resonant capacitors 561, 562, and 563, together with each of the power transmitting coils 511-519, form a power factor compensation circuit 570 that forms a resonant circuit.

[0060] According to the wireless power transmitting device 502 of this embodiment, even if the number of power transmitting coils 511 to 519 is large, all of the power transmitting coils 511 to 519 can be handled without increasing the number of legs of the inverter circuit 40.

[0061] 14 and 15 show a seventh embodiment of the present invention, with Fig. 14 being an explanatory plan view of a power transmitting coil and Fig. 15 being a circuit diagram of a power transmitting device in a wireless power transmitting system. Note that although Fig. 14 and 15 do not show a power receiving device, a power receiving coil, etc., they are the same as those in the first embodiment.

[0062] As shown in Fig. 14, in this wireless power transmitting device 602, a plurality of power transmitting coils 611 to 619 are aligned in the horizontal and vertical directions on a predetermined plane. In this embodiment, the same power transmitting coils are used for each of the power transmitting coils 611 to 619. As shown in Fig. 14, the power transmitting device 602 includes an inverter circuit 640 having four legs 41, 42, 43, and 44. Each of the power transmitting coils 611 to 619 is assigned to one of four power transmitting groups corresponding to the number of legs 41, 42, 43, and 44.

[0063] 14 , in each of the power transmission coils 611 to 619, a power transmission coil belonging to the second power transmission group is arranged horizontally adjacent to a power transmission coil belonging to the first power transmission group, a power transmission coil belonging to the third power transmission group is arranged vertically adjacent to a power transmission coil belonging to the first power transmission group, and a power transmission coil belonging to the fourth power transmission group is arranged horizontally adjacent to a power transmission coil belonging to the third power transmission group. That is, when viewed horizontally, the power transmission coils belonging to the first and second power transmission groups are alternately arranged, or the power transmission coils belonging to the third and fourth power transmission groups are alternately arranged. Also, when viewed vertically, the power transmission coils belonging to the first and third power transmission groups are alternately arranged, or the power transmission coils belonging to the second and fourth power transmission groups are alternately arranged.

[0064] 15, legs 41, 42, 43, and 44 of an inverter circuit 640 of a wireless power transmitting device 602 are connected to the other end of each of the power transmitting coils 611 to 619 via changeover switches 681, 682, 683, and 684. Each of the changeover switches 681, 682, 683, and 684 is provided for each power transmitting group, and selectively supplies power to one of the power transmitting coils 611 to 619 belonging to each power transmitting group. In this embodiment, each of the changeover switches 681, 682, 683, and 684 forms a switching circuit. A control unit 680 switches each of the changeover switches 681, 682, 683, and 684 based on information related to the power receiving coil. Furthermore, in this embodiment, a mutual inductance compensation circuit 690 that adjusts the mutual inductance based on the difference in mutual inductance between the power transmitting coils 611 to 619 is interposed between each of the changeover switches 681, 682, 683, 684 and each of the legs 41, 42, 43, 44. Furthermore, the control unit 680 controls the currents in the power transmitting coils 611 to 619 so that the ratio of the currents in the power transmitting coils 611 to 619 matches the ratio of the mutual inductance between each of the power transmitting coils 611 to 619 and the power receiving coil.

[0065] One end of each of the transmitting coils 611-619 is connected to one another and connected to an intermediate voltage of the input voltage of the DC power supply 30 via an inductor 660. Selector switches 681, 682, 683, and 684 selectively connected to the other end of each of the transmitting coils 611-619 are connected to the legs 41, 42, 43, and 44 via resonant capacitors 661, 662, 663, and 664, respectively. In this embodiment, the inductor 660 and the resonant capacitors 661, 662, 663, and 664, together with each of the transmitting coils 611-619, form a power factor compensation circuit 670 that forms a resonant circuit.

[0066] The wireless power transmitting device 602 of this embodiment can also accommodate all of the power transmitting coils 611 to 619 without increasing the number of legs of the inverter circuit 640, even when there are a large number of power transmitting coils 611 to 619.

[0067] Although the sixth and seventh embodiments have shown inverter circuits with three and four legs, the number of legs may be two, five or more, or any other number. Furthermore, although the resonant capacitors 661, 662, 663, and 664 are provided on the other end of each of the power transmitting coils 611-619, as shown in Fig. 16, the resonant capacitors 661, 662, 663, and 664 may be provided on one end of each of the power transmitting coils 611-619. If the self-inductances of the power transmitting coils 611-619 are different from one another, a resonant capacitor may be provided in series with each of the power transmitting coils 611-619.

[0068] Although the above-described embodiments have been described with reference to a power transmitting device having a plurality of identical power transmitting coils, multiple power transmitting coils having different self-inductances due to, for example, different wire types, materials, sizes, number of turns, shapes, etc. may also be provided. While the power transmitting coils are shown positioned on the same plane, they do not necessarily need to be positioned on the same plane, nor do they need to be regularly arranged, and the mutual inductance between the power transmitting coils may not necessarily have regularity. An example of a circuit diagram of a power transmitting device in such a case is shown in FIG. 17. The circuit diagram in FIG. 17 is the same as FIG. 9 except for the power transmitting coils 1111, 1112, and 1113, the power factor compensation circuit 1370, and the mutual inductance compensation circuit 1390.

[0069] The three transmitting coils 1111, 1112, and 1113 in the circuit diagram of Fig. 17 have different specifications, are not arranged on the same plane, and are also spaced apart from one another. The circuit diagram of Fig. 17 includes a mutual inductance compensation circuit 1390 including three transformers 1391, 1392, and 1393 corresponding to the combinations of the transmitting coils 1111, 1112, and 1113. The circuit diagram of Fig. 17 also includes a power factor compensation circuit 1370 including an inductor 1360 and resonant capacitors 1361, 1362, and 1363 corresponding to the transmitting coils 1111, 1112, and 1113.

[0070] Here, the current and self-inductance of the first to third power transmitting coils 1111, 1112, and 1113 are expressed as I t1 ,I t2 ,I t3 ,L t1 ,L t2 ,L t3 , the capacitance of each resonant capacitor 1361, 1362, 1363 is C t1 ,C t2 ,C t3 , the self-inductance and mutual inductance on the first and second power transmitting coil sides of the transformer 1391 corresponding to the first and second power transmitting coils are expressed as L c121 ,L c122 ,M c12, the self-inductance and mutual inductance on the second and third power transmitting coil sides of the transformer 1392 corresponding to the second and third power transmitting coils are expressed as L c232 ,L c233 ,M c23 , the self-inductance and mutual inductance on the third and first power transmitting coil sides of the transformer 1393 corresponding to the third and first power transmitting coils are expressed as L c313 ,L c311 ,M c31 , the mutual inductance between the first transmitting coil and the second transmitting coil is M t12 , the mutual inductance between the second transmitting coil and the third transmitting coil is M t23 , the mutual inductance between the third transmitting coil and the first transmitting coil is M t31 , the inductance of the inductor 1360 is L0, the mutual inductance between the first to third transmitting coils and the receiving coil is M t1r ,M t2r ,M t3r , the current in the receiving coil is I r When the winding resistances of the first to third power transmitting coils 1111, 1112, and 1113 are ignored, the output phase voltage V of the inverter circuit 340 is t1 ,V t2 ,V t3 is expressed as follows: TIFF0007818276000001.tif61155Here, any real number M´ t In contrast, TIFF0007818276000002.tif2655 is valid c12 ,M c23 ,M c31 and L´ t1 ,L´ t2 ,L´ t3 of If the image is TIFF0007818276000003.tif2669, then equations (1)-(3) are: The result is TIFF0007818276000004.tif59132. TIFF0007818276000005.tif41154. And C t1 ,C t2 ,Ct3 of, TIFF0007818276000006.tif4060, M´ t If is negative, TIFF0007818276000007.tif739, the output phase voltage V of the inverter circuit 340 t1 ,V t2 ,V t3 teeth, TIFF0007818276000008.tif2353. In other words, the reactance components due to the self-inductance and mutual inductance of each transmitting coil are cancelled out. t is positive, the inductor 1360 is replaced by a capacitance C0, TIFF0007818276000009.tif1544, equations (20)-(22) can be obtained. Also in the circuit diagram of FIG. 17, the control unit 380 M t1r :M t2r :M t3r =I t1 :I t2 :I t3 As can be seen from the equations (20) to (22), the output phase voltage V of the inverter circuit 340 is t1 ,V t2 ,V t3 The ratio of the mutual inductance M t1r ,M t2r ,M t3r Therefore, the control unit 380 can control the ratio of the currents in the power transmitting coils in accordance with the ratio of the output phase voltages of the inverter circuit 340. If the winding resistance cannot be ignored, set the resistance value of each transmitting coil to r t1 ,r t2 ,r t3 Then, the output phase voltage V of the inverter circuit 340 t1 ,V t2 ,V t3 teeth, TIFF0007818276000010.tif2462. Therefore, the resistance value r of each transmitting coil is t1 ,r t2 ,r t3 The information on the above may be acquired in advance by measurement or the like, and the mutual inductance ratio may be calculated from the values ​​of the output phase voltage and current of the inverter circuit 340.

[0071] Furthermore, in each of the above embodiments, the inverter circuit is connected to a DC power supply, but for example, as shown in Fig. 18, the inverter circuit 1040 may be connected to an AC power supply 1030, and the detailed circuit configuration can be changed as desired. The circuit diagram in Fig. 18 differs from the circuit diagram in Fig. 1 in that an AC power supply 1030 is provided instead of the DC power supply 30, and a first circuit 1051 and a second circuit 1052 are provided instead of the positive side capacitor 51 and the negative side capacitor 52. The first circuit 1051 is, for example, a diode rectifier circuit, an AC-DC converter, or the like, and outputs a DC voltage in response to an input from the AC power supply 1030. Second circuit 1054 is, for example, a diode rectifier circuit, an AC-DC converter, a DC-DC converter, or a series capacitor with a balancer, and its input terminals are connected to positive and negative buses or a separate DC or AC power supply, and its output terminals are connected to one end of each of power transmitting coils 11, 12, and 13. It is designed so that a predetermined voltage is applied to each of power transmitting coils 11, 12, and 13. This predetermined voltage can be set arbitrarily, and when the input voltage of AC power supply 1030 is E, the predetermined voltage can of course be E / 2, but it can also be 0 or E.

[0072] Furthermore, in each of the above-described embodiments, the resonant capacitors of the power factor compensation circuit of the power transmitting device are connected in series with the power transmitting coils to form series resonant circuits, but the configuration of the power factor compensation circuit can be changed as desired; for example, the resonant capacitors and the power transmitting coils may be connected in parallel to form parallel resonant circuits, or an LCL resonant circuit may be formed as shown in Fig. 19. In a power factor compensation circuit 770 of a power transmitting device 702 of Fig. 19, the other ends of the power transmitting coils 11, 12, and 13 are connected to legs 41, 42, and 43 via resonant inductors 761, 762, and 763, respectively, and are also connected to an intermediate voltage of the input voltage via resonant capacitors 764, 765, and 766.

[0073] In the above-described embodiments, the capacitance of each resonant capacitor is set so that the reactance component of the power transmission device is zero, and power can be transmitted at a relatively low input voltage. However, for example, as shown in Fig. 20, capacitors 41d, 41e, 42d, 42e, 43d, and 43e may be connected in parallel with switching elements 41a, 41b, 42a, 42b, 43a, and 43b, and the capacitance of each resonant capacitor 61, 62, and 63 may be set so that the output impedance of inverter 40 has a lagging power factor. This may result in soft switching of inverter 40, improving power transmission efficiency. Furthermore, the capacitance of each resonant capacitor 61, 62, and 63 may be set so that the output impedance of inverter 40 has a lagging power factor, utilizing the parasitic capacitance of switching elements 41a, 41b, 42a, 42b, 43a, and 43b instead of capacitors 41d, 41e, 42d, 42e, 43d, and 43e.

[0074] In addition, in each of the above-described embodiments, the resonant capacitor of the power factor compensation circuit of the power receiving device is connected in series with the power receiving coil to form a series resonant circuit. However, the configuration of the power factor compensation circuit can be changed as desired. For example, each resonant capacitor and each power transmitting coil may be connected in parallel to form a parallel resonant circuit, as shown in FIG. 21, or an LCL resonant circuit may be formed as shown in FIG. 22. In a power receiving device 803 of FIG. 21, a power receiving coil 20 and a resonant capacitor 821 are connected in parallel to an output circuit 822. In a power receiving device 903 of FIG. 22, a power receiving coil 20 and a resonant capacitor 921 are connected in parallel to an output circuit 923, and a resonant inductor 922 is provided between one end of the power receiving coil 20 and the output circuit 923. The output circuits 822 and 923 may be, for example, an AC load, a DC load via a rectifier or an AD converter, or the like.

[0075] Here, the power transmission efficiency was compared by simulation using the power transmission device 2 of the first embodiment as an example and a power transmission device with a conventional configuration as a comparative example. Fig. 23 is a circuit diagram of the power transmission device showing the comparative example, and Fig. 24 shows the simulation results showing the power transmission efficiencies of the example and the comparative example.

[0076] As shown in FIG. 23, in the power transmitting device of the comparative example, power is supplied from one inverter circuit to any one of power transmitting coils 11, 12, and 13 arranged in the same manner as in the first embodiment. 24, in the power transmission device of the example, the area of ​​the power receiving coil 20 that can transmit power is expanded and the power transmission efficiency is improved compared to the power transmission device of the comparative example. In particular, when the power receiving coil 20 is located in the joint portion of each of the power transmission coils 11, 12, and 13, the power transmission efficiency is dramatically improved.

[0077] Although the embodiments of the present invention have been described above, the invention according to the claims is not limited to the embodiments described above. It should be noted that not all of the combinations of features described in the embodiments are necessarily essential to the means for solving the problems of the invention. [Explanation of symbols]

[0078] 1. Wireless power transmission system 2. Power transmission equipment 3 Power receiving device 11. Transmission coil 12. Transmission coil 13 Transmission coil 20 receiving coil 30 DC power supply 40 Inverter circuit Leg 41 42 Legs 43 Leg 44 Legs 60 inductor 61 Resonant Capacitor 62 Resonant Capacitor 63 Resonant Capacitor 70 Power factor compensation circuit 80 Control Unit 101 Wireless Power Transmission System 102 Power transmission equipment 103 Power receiving device 111 Transmission coil 112 Transmission coil 113 Transmission Coil 114 Transmission Coil 120 receiving coil 130 DC power supply 140 Inverter circuit 141 Leg 142 Legs 143 Leg 144 Legs 160 Inductor 161 Resonant Capacitor 162 Resonant Capacitor 170 Power Factor Compensation Circuit 180 Control Unit 201 Wireless Power Transmission System 202 Power transmission equipment 260 capacitor 270 Power Factor Compensation Circuit 301 Wireless Power Transmission System 302 Power transmission equipment 340 Inverter Circuit 360 inductor 361 Resonant Capacitor 362 Resonant Capacitor 363 Resonant Capacitor 370 Power Factor Compensation Circuit 380 Control Unit 390 Mutual inductance compensation circuit 391 Transformers 392 Transformers 402 Power transmission equipment 440 Inverter Circuit 460 inductor 461 Resonant Capacitor 462 Resonant Capacitor 463 Resonant Capacitor 464 Resonant Capacitor 470 Power Factor Compensation Circuit 480 Control Unit 490 Mutual inductance compensation circuit 491 Transformers 492 Transformers 502 Power transmission equipment 511 Transmission coil 512 Transmission coil 513 Transmission Coil 514 Transmission Coil 515 Transmission Coil 516 Transmission Coil 517 Transmission Coil 518 Transmission Coil 519 Transmission Coil 560 inductor 561 Resonant Capacitor 562 Resonant Capacitor 563 Resonant Capacitor 570 Power Factor Compensation Circuit 580 Control Unit 581 Changeover switch 582 Switch 583 Changeover switch 602 Power transmission equipment 611 Transmission Coil 612 Transmission coil 613 Transmission Coil 614 Transmission Coil 615 Transmission Coil 616 Transmission Coil 617 Transmission Coil 618 Transmission Coil 619 Transmission Coil 640 Inverter Circuit 660 Inductor 661 Resonant Capacitor 662 Resonant Capacitor 663 Resonant Capacitor 664 Resonant Capacitor 670 Power Factor Compensation Circuit 680 Control Unit 681 Changeover switch 682 Changeover switch 683 Changeover switch 684 Switch 690 Mutual inductance compensation circuit 702 Power transmission equipment 761 Resonant Inductor 762 Resonant Inductor 763 Resonant Inductor 764 Resonant Capacitor 765 Resonant Capacitor 766 Resonant Capacitor 770 Power Factor Compensation Circuit 803 Powered Device 821 Resonant Capacitor 822 Output circuit 903 Powered Device 921 Resonant Capacitor 922 Resonant Inductor 923 Output Circuit 1111 Transmission coil 1112 Transmission coil 1113 Transmission coil 1360 inductor 1361 Resonant Capacitor 1362 Resonant Capacitor 1363 Resonant Capacitor 1370 Power Factor Compensation Circuit 1390 Mutual inductance compensation circuit 1391 Transformer 1392 Transformer 1393 Transformer

Claims

1. A power transmission device in a wireless power transmission system that transmits power wirelessly between a power transmitting coil and a power receiving coil, a plurality of the power transmitting coils provided for one of the power receiving coils; an inverter circuit connected to a predetermined power supply, having a plurality of legs connected in parallel with each other, and supplying power to each of the power transmitting coils; a power factor compensation circuit that forms a resonant circuit together with each of the power transmitting coils, one end of each of the power transmission coils is connected to each other, a connection portion on one end side of each of the power transmission coils is connected to a portion of the inverter circuit that has a predetermined voltage; The power factor compensation circuit is a power transmission device of a wireless power transmission system including an inductor or a capacitor interposed between a connection portion on one end side of each of the power transmission coils and a portion of the inverter circuit at the predetermined voltage.

2. The power transmitting device of the wireless power transmitting system according to claim 1 , wherein the power factor compensation circuit includes a capacitor provided for each of the power transmitting coils.

Images