Contactless power supply device

Abstract

A contactless power supply device (100) for supplying electric power to a power receiving device (200) in a contactless manner comprises: a power transmission circuit (130) for transmitting AC power; and a power transmission resonance section having a power transmission coil (112). In a relative state where the power receiving coil (212) of the power receiving device is relative to the power transmission coil, the input impedance of the power transmission resonance section is set to be small, and in a non-relative state where the power receiving coil is not relative to the power transmission coil, the input impedance of the power transmission resonance section is set to be large.

Description

Technical Field

[0001] The invention relates to a contactless power supply device. Background Art

[0002] Japanese Patent Publication No. 2019-71719 discloses a wireless power supply system, which includes: a plurality of power transmission coils connected to a high-frequency power supply in parallel; and a power receiving coil installed on a moving body. A current control element (such as a saturated inductor) is arranged between the high-frequency power supply and each power transmission coil. In the current control element, when the current flowing from the high-frequency power supply to the power transmission coil is less than a threshold value, the impedance increases, and when the current flowing from the high-frequency power supply to the power transmission coil is above the threshold value, the impedance decreases. As a result, the impedance of the current control element arranged in the power transmission coil that is not opposite to the power receiving coil increases, which suppresses the supply of current from the high-frequency power supply to the power transmission coil.

[0003] However, in the structure of the prior art, it is necessary to include a current control element for changing impedance separately from the power transmission coil and the resonance capacitor constituting the power transmission resonance circuit for contactless power supply. In addition, the saturated reactor exemplified as the current control element needs to increase the inductance to increase the impedance, so the saturated reactor used as the current control element is enlarged. Summary of the invention

[0004] According to one embodiment of the present invention, there is provided a contactless power supply device for supplying electric power to a power receiving device in a contactless manner. The contactless power supply device 100 includes a power transmission circuit 130 for transmitting AC power and a power transmission resonance unit having a power transmission coil 112, wherein the input impedance of the power transmission resonance unit is set to be small when the power receiving coil 212 of the power receiving device 200 is in a relative state relative to the power transmission coil, and the input impedance of the power transmission resonance unit is set to be large when the power receiving coil is not in a relative state relative to the power transmission coil.

[0005] According to the contactless power supply device of the above-mentioned method, the input impedance of the power transmission resonance part having the power transmission coil not opposite to the power receiving coil becomes larger, so that the current supplied from the power transmission circuit to the power transmission coil not opposite to the power receiving coil can be suppressed. As a result, the loss and leakage flux in the power transmission coil that does not transmit power can be reduced without using large components such as the current control element of the prior art. In addition, the current is automatically supplied only to the power transmission coil opposite to the power receiving coil, so the position sensor for determining the position of the power receiving coil and the control for switching between the case where power is transmitted to the power transmission coil and the case where power is not transmitted can be omitted. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings.

[0007] Figure 1 It is an explanatory diagram showing the contactless power supply device and the power receiving device according to the first embodiment.

[0008] Figure 2 It is an explanatory diagram showing the arrangement relationship of the power receiving coil with respect to the power transmitting coil.

[0009] Figure 3 1 is an explanatory diagram showing an equivalent circuit of a contactless power supply device and a power receiving device in a facing state.

[0010] Figure 4 1 is an explanatory diagram showing an equivalent circuit of a contactless power supply device in a non-opposing state.

[0011] Figure 5 It is an explanatory diagram showing a contactless power supply device and a power receiving device provided with a filter circuit.

[0012] Figure 6 It is an explanatory diagram showing the configuration of a power transmission resonance circuit according to the second embodiment.

[0013] Figure 7 It is an explanatory diagram showing an example of the arrangement of the resonance capacitor.

[0014] Figure 8 It is an explanatory diagram showing the configuration of a power transmission resonance circuit according to a third embodiment.

[0015] Fig. 9 This is an explanatory diagram showing an example of the inductance of the power transmission coil.

[0016] Fig.10 This is an explanatory diagram showing the reason why the inductance of the power transmission coil changes.

[0017] Fig.11 It is an explanatory diagram showing a contactless power supply device according to a fourth embodiment.

[0018] Fig.12 It is an explanatory diagram showing an example of the relationship between the capacitance of the resonant capacitor and the control voltage.

[0019] Fig.13 It is an explanatory diagram showing an example of the relationship between the capacitance of the resonance capacitor and the facing area.

[0020] Fig.14 It is an explanatory diagram showing another example of the relationship between the capacitance of the resonance capacitor and the facing area.

[0021] Fig.15This is an explanatory diagram showing still another example of the relationship between the capacitance of the resonance capacitor and the facing area.

[0022] Fig.16 It is an explanatory diagram showing a contactless power supply device according to a fifth embodiment.

[0023] Fig.17 It is an explanatory diagram showing a contactless power supply device according to a sixth embodiment.

[0024] Fig.18 It is an explanatory diagram showing a contactless power supply device according to a seventh embodiment.

[0025] Fig.19 It is an explanatory diagram showing a contactless power supply device according to an eighth embodiment.

[0026] Fig. 20 It is a flow chart of power supply control.

[0027] Fig.21 It is an explanatory diagram showing another structure of the variable control circuit.

[0028] Fig. 22 It is an explanatory diagram showing still another configuration of the variable control circuit.

[0029] Fig.23 It is an explanatory diagram showing a contactless power supply device according to a ninth embodiment.

[0030] Fig.24 It is an explanatory diagram showing a contactless power supply device according to a tenth embodiment.

[0031] Fig.25 It is an explanatory diagram showing a contactless power supply device according to an eleventh embodiment.

[0032] Fig.26 It is an explanatory diagram showing a contactless power supply device according to a twelfth embodiment.

[0033] Fig. 27 It is an explanatory diagram showing a contactless power supply device according to a thirteenth embodiment.

[0034] Fig.28 It is an explanatory diagram showing a contactless power supply device according to a fourteenth embodiment.

[0035] Fig.29 It is an explanatory diagram showing a contactless power supply device according to a fifteenth embodiment.

[0036] Fig.30 It is an explanatory diagram showing a contactless power supply device according to a sixteenth embodiment.

[0037] Fig.31 It is an explanatory diagram showing another structure of the contactless power supply device according to the sixteenth embodiment.

[0038] Fig.32 It is an explanatory diagram showing still another configuration of the contactless power supply device according to the sixteenth embodiment.

[0039] Fig.33 It is a schematic configuration diagram of a non-contact power supply system for a vehicle according to a seventeenth embodiment.

[0040] Fig.34 This is another schematic configuration diagram of the non-contact power supply system for a vehicle according to the seventeenth embodiment.

[0041] Fig.35 This is another schematic configuration diagram of the non-contact power supply system for a vehicle according to the seventeenth embodiment.

[0042] Fig.36 is an explanatory diagram showing the dimensions of a power transmission coil laid on a vehicle travel route;

[0043] Fig.37 It is an explanatory diagram showing the dimensions of a power transmission coil laid on a vehicle travel path. DETAILED DESCRIPTION

[0044] A. First Implementation Method:

[0045] Figure 1 The contactless power supply device 100 shown is a power supply device that can supply power to a power receiving device 200 in a contactless manner, and the power receiving device 200 and the contactless power supply device 100 are arranged in a relative state in which the power receiving coil 212 of the power receiving device 200 is electromagnetically coupled to the power transmitting coil 112 of the contactless power supply device 100. Figure 1 , a comparison is shown between a case where the power receiving device 200 is in an opposing state and a case where the power receiving device 200 is in a non-opposing state with respect to the contactless power supply device 100. The power receiving device 200 is installed in various devices that operate using electric power, such as electronic equipment and electric vehicles.

[0046] The contactless power supply device 100 includes a power supply circuit 140 , a power transmission circuit 130 , and a power transmission resonance circuit 110 . The power reception device 200 includes a power reception resonance circuit 210 , a power reception circuit 220 , and a battery 230 .

[0047] The power transmission resonance circuit 110 is a resonance circuit including a power transmission coil 112 and a power transmission resonance capacitor 116 connected in series. The power receiving resonance circuit 210 is also a resonance circuit including a power receiving coil 212 and a power receiving resonance capacitor 216 connected in series, similarly to the power transmission resonance circuit 110. The power transmission resonance circuit 110 is a device that transmits AC power to the power receiving device 200 in a non-contact manner when the power transmission resonance circuit 110 and the power receiving resonance circuit 210 resonate in a state where the power receiving coil 212 faces the power transmission coil 112 and the power transmission coil 112 and the power receiving coil 212 are electromagnetically coupled. The power transmission resonance circuit 110 is a device that obtains the AC power induced in the power receiving coil 212. A resonance method (referred to as "SS method") implemented by a primary series and a secondary series capacitor is applied to the power transmission resonance circuit 110 and the power receiving resonance circuit 210. In addition, a non-contact power supply method of power transmission side single phase - power reception side single phase is applied, in which the power transmission side is constituted by a single-phase power transmission coil 112 and the power reception side is constituted by a single-phase power reception coil 212. In addition, the inductance of the power transmission coil 112 is represented by Lt, and the capacitance of the power transmission resonance capacitor 116 is represented by Ct. In addition, the inductance of the power reception coil 212 is represented by Lr, and the capacitance of the power reception resonance capacitor 216 is represented by Cr. The parameters of the power transmission resonance circuit 110 and the power reception resonance circuit 210, that is, the inductance of the coil and the capacitance of the capacitor will be described later.

[0048] The power transmission circuit 130 is a circuit that converts the DC power supplied from the power supply circuit 140 into high-frequency AC power and supplies it to the power transmission coil 112. The power transmission circuit 130 is configured as an inverter circuit, for example. The power supply circuit 140 is configured as an AC / DC converter circuit that rectifies the AC voltage of an external power supply to output a DC voltage.

[0049] The power receiving circuit 220 is a circuit that converts the AC power obtained by the power receiving resonance circuit 210 into DC power and charges the DC power to the battery 230 as a load. The power charged in the battery 230 is used to drive a motor (not shown) or the like.

[0050] Here, if Figure 2 As shown, in the state where the power receiving coil 212 is opposite to the power transmitting coil 112 (hereinafter referred to as the "opposing state"), there are a "facing state" and a "partially overlapping state". In addition, in the state where the power receiving coil 212 is not opposite to the power transmitting coil 112 (hereinafter referred to as the "non-opposing state"), there are a "critical state", a "separated state" and an "isolated state".

[0051] The "facing state" is a state in which the center of the coil surface of the power transmission coil 112 coincides with the center of the coil surface of the power receiving coil 212, and one of the coil surfaces of the power transmission coil 112 and the power receiving coil 212 overlaps with the other as a whole. In this facing state, the relative area between the power transmission coil 112 and the power receiving coil 212 is the largest. In addition, the "coil surface" is a surface surrounded by an annular wiring and functions as an annular coil. However, the power transmission coil and the power receiving coil are not limited to annular coils, but can also be solenoid coils. The "partial overlap state" is a state in which the coil surface of the power receiving coil 212 is relatively deviated from the coil surface of the power transmission coil 112 and there is a partially overlapping surface, which is a state in which the relative area is reduced compared to the relative area of ​​the power transmission coil 112 and the power receiving coil 212 in the facing state. The "critical state" is a state in which the coil surface of the receiving coil 212 deviates from the coil surface of the transmitting coil 112 without relative overlap and the end edge of the coil surface of the transmitting coil 112 overlaps the end edge of the coil surface of the receiving coil 212, which is a state at the moment when the relative area just disappears. The "separated state" is a state in which the coil surface of the receiving coil 212 deviates from the coil surface of the transmitting coil 112 without relative overlap and the coil surface of the transmitting coil 112 is completely separated from the coil surface of the receiving coil 212. The "isolated state" is a state in which the coupling coefficient is very small even when the transmitting coil 112 and the receiving coil 212 are in a relative state, and the separation can be treated as a distance greater than that which can be treated as no electromagnetic coupling. In contrast, in the above relative state, the distance between the transmitting coil 112 and the receiving coil 212 is a distance less than a certain distance such that coupling with a coupling coefficient of a certain magnitude or more occurs in the directly facing state.

[0052] like Figure 1 As shown, the AC power from the power transmission circuit 130 is supplied to the power transmission coil 112 in a state facing the power receiving coil 212 as described later. In addition, by electromagnetically coupling the power transmission coil 112 and the power receiving coil 212, the AC power is transmitted from the power transmission coil 112 to the power receiving coil 212. The AC power transmitted to the power receiving coil 212 is charged to the battery 230 via the power receiving circuit 220. On the other hand, the power transmission coil 112 in a state not facing the power receiving coil 212 is not supplied with AC power from the power transmission circuit 130 as described later.

[0053] Here, the impedance Z110 of the power transmission resonance circuit 110 alone is expressed by the following equation (1). Similarly, the impedance Z210 of the power reception resonance circuit 210 alone is expressed by the following equation (2).

[0054] [Mathematical formula 1]

[0055]

[0056] [Mathematical formula 2]

[0057]

[0058] The resonance condition of the power transmission resonance circuit 110 is when (ωLt-1 / (ωct))=0 in the above equation (1) is satisfied. The resonance condition of the power receiving resonance circuit 210 is also when (ωLr-1 / (ωcr))=0 in the above equation (2) is satisfied. Therefore, when the power transmission coil 112 and the power receiving coil 212 face each other and power is transmitted from the power transmission resonance circuit 110 to the power receiving resonance circuit 210, the inductance Lt of the power transmission coil 112 and the capacitance Ct of the power transmission resonance capacitor 116 are set so that the resonance condition of the power transmission resonance circuit 110 is satisfied and the resonance frequency frt coincides with the fundamental frequency fsw of the AC power. Similarly, the inductance Lr of the power receiving coil 212 and the capacitance Cr of the power receiving resonance capacitor 216 are set so that the resonance condition of the power receiving resonance circuit 210 is satisfied and the resonance frequency frr coincides with the fundamental frequency fsw of the AC power. In the following, as the inductance and capacitance that satisfy the resonance condition, the inductance Lt of the power transmission coil 112 is represented by L1, and the capacitance Ct of the power transmission resonance capacitor 116 is represented by C1. In addition, the inductance Lr of the power reception coil 212 is represented by L2, and the capacitance Cr of the power reception resonance capacitor 216 is represented by C2. In addition, the inductance L1 and L2 are referred to as "resonance inductance L1 and L2", and the capacitance C1 and C2 are referred to as "resonance capacitance C1 and C2". In addition, the resonance frequency frt of the power transmission resonance circuit 110 is represented by the following equation (3a), and the resonance frequency frr of the power reception resonance circuit 210 is represented by the following equation (3b).

[0059] [Mathematical formula 3]

[0060]

[0061] Here, in a state where the power transmission coil 112 and the power reception coil 212 are facing each other and power is transmitted from the power transmission resonance circuit 110 to the power reception resonance circuit 210 (facing state), Figure 3 The equivalent circuit shown in FIG. 1 represents the contactless power supply device 100 and the power receiving device 200 (see FIG. Figure 1 In addition, Lm is the mutual inductance between the power transmission coil 112 and the power reception coil 212, rt is the resistance of the power transmission coil 112, and rr is the resistance of the power reception coil 212. RL is a load that represents the power reception circuit 220 and the battery 230 equivalently.

[0062] exist Figure 3 In the equivalent circuit of , the input impedance Z1 (= V1 / I1 ) of the power transmission resonance circuit 110 is expressed by the following equation (4).

[0063] [Formula 4]

[0064]

[0065] As described above, the input impedance Z1=Z1r when the resonance conditions of the power transmission resonance circuit 110 and the power reception resonance circuit 210 are satisfied is expressed by the following equation (5a) by substituting Lt=L1, Ct=C1, Lr=L2, Cr=C2 into the above equation (4). In the following equation (5a), rt=r1 and rr=r2 are expressed corresponding to Lt=L1 and Lr=L2.

[0066] [Mathematical formula 5]

[0067]

[0068] In the above equation (5), the imaginary term becomes "0" due to resonance, so the input impedance Z1r is expressed by the above equation (5b). In addition, usually r1<<RL, R2<<RL, so the input impedance Z1r is expressed by the above equation (5c). Therefore, when the power transmission coil 112 and the power reception coil 212 are facing each other, the power transmission circuit 130 ( Figure 3 ) outputs the AC power corresponding to the input impedance Z1r represented by the above equation (5b) or the above equation (5c) to the power transmission resonance circuit 110. Then, the AC power is transmitted from the power transmission resonance circuit 110 to the power receiving resonance circuit 210. Hereinafter, the input impedance Z1=Z1r in the state where the power transmission coil 112 and the power receiving coil 212 are opposite to each other is referred to as "the input impedance Z1 in the opposite state".

[0069] On the other hand, it can be used Figure 4 The equivalent circuit shown in FIG. 1 is used to represent a portion of the contactless power supply device 100 in a state where the power transmission coil 112 and the power reception coil 212 are not facing each other and power is not transmitted from the power transmission resonance circuit 110 to the power reception resonance circuit 210 (see FIG. 1 ). Figure 1 ). Figure 4 In the equivalent circuit of , the input impedance Z1 (= V1 / I1) = Z1n of the power transmission resonance circuit 110 is expressed by the following equation (6) in the same manner as the impedance Z110 of the power transmission resonance circuit 110 alone. In addition, the input impedance Z1 = Z1n in the state where the power transmission coil 112 and the power reception coil 212 are not facing each other is hereinafter referred to as "input impedance Z1 in the non-facing state".

[0070] [Mathematical formula 6]

[0071]

[0072] Here, in the input impedance Z1=Z1n in the non-relative state represented by the above formula (6), when at least one of Lt<L1 and Lt>L1 and Ct<C1 is satisfied, the resonant state of the power transmission resonance circuit 110 (the state of Z1n=Z110=0) collapses. At this time, the input impedance Z1 in the non-relative state can be increased from Z1=Z1n=0 to Z1=Z1n>0, and becomes larger than the input impedance Z1=Z1r in the relative state. As a result, the current supplied to the input impedance Z1=Z1n in the non-relative state can be reduced compared to the current supplied to the input impedance Z1=Z1r in the relative state.

[0073] In the configuration described above, when the power receiving coil 212 of the power receiving device 200 is facing the power transmitting coil 112 of the power transmitting resonance circuit 110, the input impedance Z1 is reduced to Z1=Z1r due to the resonance of the power transmitting resonance circuit 110. In addition, when the power receiving coil 212 is not facing the power transmitting coil 112, the input impedance Z1 is increased to Z1=Z1n>Z1r due to the non-resonance of the power transmitting resonance circuit 110. Thus, the power transmitting circuit 130 can supply a large current corresponding to the small input impedance Z1=Z1r when the power transmitting coil 112 and the power receiving coil 212 are facing each other. On the other hand, when the power transmitting coil 112 and the power receiving coil 212 are not facing each other, the power transmitting circuit 130 can suppress the supply of current by the large input impedance Z1=Z1n. Thus, without using a large component such as a current control element in the related art, it is possible to reduce the loss in the power transmission coil 112 that is not opposite to the power reception coil 212, and to reduce the leakage magnetic flux from the power transmission coil 112 that is not opposite to the power reception coil 212. In addition, it is possible to omit a structure for switching between transmission and non-transmission of electric power from the power transmission circuit 130 to the power transmission coil 112 of the power transmission resonance circuit 110 in the opposite state and the non-opposite state.

[0074] In addition, if Figure 5 As shown, a filter circuit 120 can be provided between the power transmission resonance circuit 110 and the power transmission circuit 130. The filter circuit 120 is a circuit for suppressing high-frequency noise components such as switching noise contained in the AC power supplied from the power transmission circuit 130. As the filter circuit 120, various filter circuits such as an impedance filter circuit, a low-pass filter circuit, and a band-pass filter circuit can be used. The number of poles of the filter circuit can be two-stage, three-stage, or four-stage or more. If the noise to be removed can be reduced to the desired level, the number of poles of the filter circuit is not limited. In addition, in Figure 1 In the case of the structure without the filter circuit shown in the figure, the power transmission resonance circuit 110 corresponds to the "power transmission resonance part". Figure 5In the case of the configuration with the filter circuit shown, the filter circuit 120 and the power transmission resonance circuit 110 correspond to a “power transmission resonance section.” The power transmission resonance circuit 110 with the filter circuit can be handled in the same manner as the configuration without the filter circuit.

[0075] In addition, a filter circuit 215 for suppressing high-frequency noise components may be provided between the power receiving resonance circuit 210 and the power receiving circuit 220, similarly to the filter circuit 120 on the power transmitting side. In addition, the filter circuit 215 on the power receiving side can be applied to a configuration in which the filter circuit 120 on the power transmitting side is not provided. In addition, the filter circuit 120 on the power transmitting side can also be applied to a configuration in which the filter circuit 215 on the power receiving side is not provided.

[0076] B. Second Implementation Method:

[0077] In the second embodiment, the structure described in the first embodiment that makes the input impedance Z1 smaller in the relative state to Z1=Z1r (refer to the above formula (5c)) and larger in the non-relative state to Z1=Z1n>Z1r (refer to the above formula (6)) (hereinafter also referred to as "the structure that makes the input impedance Z1 change") is described. In the second embodiment, as the structure that makes the input impedance Z1 change, Figure 6 As shown, a configuration using a power transmission resonance capacitor 116b which is a variable capacitor having a variable capacitance is applied.

[0078] In the relative state, the capacitance Ct of the variable capacitor is set to the resonance capacitance C1 that satisfies the resonance condition so that the power transmission resonance circuit 110 is in the resonance state, and in the non-relative state, the capacitance Ct of the variable capacitor is set to a capacitance smaller than the resonance capacitance C1 so that the power transmission resonance circuit 110 is deviated from the resonance state.

[0079] Here, as a variable capacitor, a device that can change the capacitance of the capacitance Ct from a capacitance smaller than the resonance capacitance C1 to the resonance capacitance C1 according to the increase in magnetic flux generated by the increase in the current flowing in the power transmission coil 112 can be used. For example, a device that utilizes the electromagnetic effect, magnetic induction effect, magnetocapacitance effect (Japanese: magnetocapacity effect), etc. (hereinafter, also referred to as a "variable capacitor utilizing the electromagnetic effect, etc.") can be used.

[0080] In addition, a power transmission resonance capacitor 116b using a variable capacitor utilizing electromagnetic effect or the like is used. Figure 7That is, on the inner circumference of the loop-shaped wiring 312 wound around the core 310 of the power transmission coil 112, the power transmission resonant capacitor 116b is arranged on the surface of the core 310 corresponding to the coil surface along the loop-shaped wiring 312. If the power transmission resonant capacitor 116b is arranged in this way, the sensitivity of the power receiving coil 212 to the magnetic flux generated by the power transmission coil 112 when the power transmission coil 112 changes from the non-opposite state to the relative state can be increased, and the capacitance Ct of the power transmission resonant capacitor 116b can be changed from the state of Ct<C1 to the state of Ct=C1 according to the change of the magnetic flux.

[0081] As described above, in the configuration of the second embodiment, the input impedance Z1 of the power transmission resonance circuit 110 can be reduced to Z1=Z1r (see the above formula (5c)) in the relative state, and can be increased to Z1=Z1n>Z1r (see the above formula (6)) in the non-relative state. Thus, the effects described in the first embodiment can be obtained in the second embodiment.

[0082] C. Third Implementation Method:

[0083] In the third embodiment, as the structure for changing the input impedance Z1 described in the first embodiment, Figure 8 As shown, a configuration using a power transmission coil 112 c as a variable coil having a variable inductance is applied.

[0084] In the case of contactless power supply with a short gap between the power transmission coil and the power reception coil, the value of the inductance Lt of the power transmission coil varies greatly depending on the positional relationship of the power reception coil relative to the power transmission coil. For example, it has the following characteristics: Fig. 9 As shown in FIG. 1 , the inductance Lt at the facing position is the resonant inductance L1 that satisfies the resonance condition, and the inductance Lt decreases as it deviates from the facing state. The inductance Lt at the non-facing state is significantly smaller than the resonant inductance L1. The above-mentioned characteristic changes occur for the following reasons. That is, Fig.10 As shown, in the relative state, a part of the magnetic flux generated by the power transmission coil 112 (the solid line in the shape of a ring) passes through the magnetic body 211 of the power receiving coil 212 with high magnetic permeability, so the inductance of the power transmission coil 112 becomes larger. In contrast, in the non-relative state, a part of the magnetic flux generated by the power transmission coil 112 (the dotted line in the shape of a ring) passes through the air part with low magnetic permeability, so the inductance of the power transmission coil 112 becomes smaller. In addition, the above characteristics are more significant when the distance (interval) between the power transmission coil and the power receiving coil is closer and the coupling coefficient is larger. Therefore, the coupling coefficient k in the facing state is preferably set to k ≥ 0.1.

[0085] Therefore, if the power transmission coil 112 (refer to Figure 1 , Figure 5) is used in a state having the above-mentioned characteristics, the power transmission coil 112 can be set as a variable coil with variable inductance, that is, the power transmission coil 112c. In addition, in the relative state, the inductance Lt of the power transmission coil 112c is set to the resonant inductance L1 so that the power transmission resonance circuit 110 is in a resonant state. As a result, in the relative state, the input impedance Z1 can be reduced to Z1=Z1r (refer to the above formula (5c)). In addition, in the non-relative state, the inductance Lt of the power transmission coil 112c is set to a value that is significantly smaller than the resonant inductance L1 so that the power transmission resonance circuit 110 deviates from the resonant state. As a result, in the non-relative state, the input impedance Z1 can be increased to Z1=Z1n>Z1r (refer to the above formula (6)). As a result, the effect described in the first embodiment can also be obtained in the third embodiment.

[0086] In addition, a structure that applies both the above-mentioned structure that makes the inductance of the power transmission coil variable and the structure that makes the capacitance of the resonant capacitor variable in the second embodiment can also be used. In this way, in the non-relative state, the inductance of the power transmission coil is reduced, and the capacitance of the resonant capacitor is reduced, so that the input impedance Z1=Z1n in the non-relative state can be further increased, and the current flowing from the power transmission circuit 130 to the power transmission resonant circuit 110 can be reduced. In this way, the effect described in the first embodiment can be further effectively obtained. In addition, the variation range of the capacitance of the resonant capacitor required to set the input impedance in the non-relative state to be above the target value and the current flowing in the power transmission resonant circuit in the non-relative state to be below the target value can be reduced, so the setting of the capacitance of the resonant capacitor can be facilitated.

[0087] D. Fourth Implementation Method:

[0088] In the fourth embodiment, as the structure for changing the input impedance Z1 described in the first embodiment, Fig.11 As shown, the structure of the power transmission resonance capacitor 116d implemented by a variable capacitor with variable capacitance is applied. The point that a variable capacitor is used as a resonance capacitor is the same as the second embodiment. However, the variable capacitor used in the power transmission resonance capacitor 116b of the second embodiment is a variable capacitor that utilizes electromagnetic effect, etc. In contrast, the variable capacitor used in the power transmission resonance capacitor 116d of the fourth embodiment is a general variable capacitor that changes the capacitance Ct according to the control input given, in this example according to the control voltage Vc. In addition, the filter circuit 120 may not be provided.

[0089] In addition, if Fig.11As shown, the contactless power supply device 100 of the fourth embodiment is provided with a variable control circuit 320 for controlling the capacitance Ct of the power transmission resonance capacitor 116d. The variable control circuit 320 includes a current sensor 322, a rectifier circuit 324, a low pass filter circuit 326 (hereinafter referred to as "LPF circuit 326") and a voltage conversion circuit 328.

[0090] The current sensor 322 detects the current flowing in the wiring connecting the filter circuit 120 and the power transmission resonance circuit 110, that is, the current flowing in the power transmission coil 112, and outputs it as a detection voltage. In addition, the current sensor 322 can also be set to detect the current flowing in the other wiring. The rectifier circuit 324 rectifies the detection voltage. The LPF circuit 326 removes the high-frequency component of the detection voltage. The voltage conversion circuit 328 uses a differential amplifier circuit to convert the detection voltage into a control voltage Vc for controlling the capacitance Ct of the power transmission resonance capacitor 116 according to the size of the difference between the detection voltage and the reference voltage Vrc.

[0091] Here, the current detected by the current sensor 322 is very small when the power receiving coil 212 is in a non-opposite state with respect to the power transmitting coil 112, and becomes larger when the non-opposite state changes to the opposite state and the closer to the facing state. Therefore, the detection voltage of the current sensor 322 changes in accordance with the change of the above current.

[0092] In addition, if Fig.12 As shown in the graph on the right side of , the capacitance Ct of the power transmission resonance capacitor 116d becomes the resonance capacitance C1 in the facing state, and becomes the critical state of the non-facing state (refer to Figure 2 ) is set to a capacitance Cnf that is smaller than the preset resonant capacitance C1.

[0093] Here, the variable capacitor used as the power transmission resonance capacitor 116d has a characteristic that the capacitance decreases as the control voltage Vc increases. Fig.12 As shown in the diagram on the right side of Fig.11 ) is controlled to become a voltage Vf corresponding to Ct=C1 at the detection voltage corresponding to the facing state, and a voltage Vnf corresponding to Ct=Cnf (Vnf>Vf) at the detection voltage corresponding to the critical state. Therefore, the voltage conversion circuit 328 is formed as follows (refer to Fig.11): In accordance with the control of the control voltage Vc, the detection voltage is input to the negative input of the differential amplifier circuit in such a manner that the larger the detection voltage of the current sensor 322 is, the smaller the output control voltage Vc is. In addition, in the case where the variable capacitor used as the power transmission resonance capacitor 116d has the opposite characteristics, it is sufficient to form a structure in which the detection voltage is input to the positive input of the differential amplifier circuit of the voltage conversion circuit 328.

[0094] In addition, the capacitance Cnf of the power transmission resonance capacitor 116d is preferably as follows: Fig.12 As shown on the left side of , the capacitance Ct is set to the current Ic detected by the current sensor 322 and the predetermined current Inf. In addition, the predetermined current Inf is preferably set based on the following viewpoints: in the non-relative state, the loss caused by the current flowing in the power transmission coil 112 and the leakage flux are suppressed.

[0095] The variable control circuit 320 can control the capacitance Ct of the power transmission resonance capacitor 116d according to the relative state of the power receiving coil 212 and the power transmission coil 112. Therefore, in the structure of the fourth embodiment, the input impedance Z1 of the power transmission resonance circuit 110 can be reduced to Z1=Z1r (refer to the above formula (5c)) in the relative state, and increased to Z1=Z1n>Z1r (refer to the above formula (6)) in the non-relative state. Therefore, the effect described in the first embodiment can also be obtained in the fourth embodiment.

[0096] In addition, the capacitance Ct of the power transmission resonance capacitor 116d is preferably, for example, Figure 13 to Figure 15 As shown in FIG. 1 , the relative area between the power receiving coil 212 and the power transmitting coil 112 is set to be linearly deformed when it decreases from the area of ​​the largest directly facing state to the area of ​​the critical state of zero. In this way, the input impedance Z1 can be gradually increased, so that the current and voltage applied to the power transmitting coil 112 due to the rapid increase in impedance can be suppressed from generating surge current and surge voltage. In addition, the change of capacitance Ct is not limited to Figure 13 to Figure 15 The characteristics shown may be set so as to be linearly deformed when the area decreases from the maximum facing state to the critical state where the area becomes zero, and various shapes can be applied to the shape of the change.

[0097] In addition, in the structure of the fourth embodiment, a structure in which the power transmission coil of the third embodiment is made variable can also be formed. In this way, by reducing the inductance of the power transmission coil and reducing the capacitance of the resonant capacitor in the non-relative state, the input impedance Z1=Z1n in the non-relative state can be further increased. As a result, the effect described in the first embodiment can be further effectively obtained. In addition, the variation range of the capacitance of the resonant capacitor required to set the input impedance in the non-relative state to be above the target value and the current flowing in the power transmission resonant circuit in the non-relative state to be below the target value can be reduced, so the setting of the capacitance of the resonant capacitor becomes easy.

[0098] E. Fifth Implementation Method:

[0099] In the fifth embodiment, if Fig.16 As shown, the structure of the fourth embodiment (see Fig.10 ) has the same structure as the power transmission resonant capacitor 116d. However, it is different in that a variable control circuit 320e is included instead of the variable control circuit 320 of the fourth embodiment. The variable control circuit 320e is the same as the variable control circuit 320 except that a magnetic field sensor 322e is included instead of the current sensor 322 of the variable control circuit 320. In addition, the filter circuit 120 may not be provided.

[0100] The magnetic field sensor 322e is similar to the power transmission resonance capacitor 116b (see Figure 7 ), the magnetic field sensor 322e is arranged on the surface of the core 310 corresponding to the coil surface along the annular wiring 312 on the inner circumferential side of the annular wiring 312 wound around the core 310 of the power transmission coil 112. Thus, the magnetic field sensor 322e can detect the change of the magnetic flux generated by the power transmission coil 112 according to the relative state of the power receiving coil 212 and the power transmission coil 112, and output the detection voltage in the same way as the current sensor 322.

[0101] The variable control circuit 320e of the fifth embodiment can also control the capacitance Ct of the power transmission resonance capacitor 116d according to the relative state of the power receiving coil 212 and the power transmission coil 112, similarly to the variable control circuit 320 of the fourth embodiment. Therefore, in the configuration of the fifth embodiment, the input impedance Z1 of the power transmission resonance circuit 110 can be reduced to Z1=Z1r (see the above formula (5c)) in the relative state, and increased to Z1=Z1n>Z1r (see the above formula (6)) in the non-relative state. Therefore, the fifth embodiment can also obtain the effects described in the first embodiment.

[0102] In addition, in the structure of the fifth embodiment, a structure in which the power transmission coil of the third embodiment is made variable can also be formed. In this way, by reducing the inductance of the power transmission coil and reducing the capacitance of the resonant capacitor in the non-relative state, the input impedance Z1=Z1n in the non-relative state can be further increased. As a result, the effect described in the first embodiment can be further effectively obtained. In addition, the variation range of the capacitance of the resonant capacitor required to set the input impedance in the non-relative state to be above the target value and the current flowing in the power transmission resonant circuit in the non-relative state to be below the target value can be reduced, so the setting of the capacitance of the resonant capacitor becomes easy.

[0103] E. Sixth Implementation Method:

[0104] In the sixth embodiment, as the structure for changing the input impedance Z1 described in the first embodiment, a structure using a power transmission coil 112f realized by a variable coil with variable inductance is applied. The use of a variable coil as the power transmission coil is the same as the third embodiment. However, the power transmission coil 112c of the third embodiment utilizes the characteristic of changing the inductance according to the relative state of the power receiving coil and the power transmission coil. In contrast, the variable coil used in the power transmission coil 112f of the sixth embodiment is a variable coil that changes the inductance Lt according to the given control input, in this example, according to the control voltage Vl. As a variable coil, for example, various variable coils such as a variable coil that changes the inductance by changing the number of turns of the coil according to the control voltage Vl can be used. In addition, the filter circuit 120 may not be provided.

[0105] In addition, if Fig.17 As shown, the contactless power supply device 100 of the sixth embodiment is provided with a variable control circuit 320f for controlling the inductance Lt of the power transmission coil 112f. The variable control circuit 320f is different from the variable control circuit 320 of the fourth embodiment (see Fig.11 However, the reference voltage input to the voltage conversion circuit 328 and the control voltage output are voltages for controlling the inductance Lt of the power transmission coil 112f, and therefore, can be set to a reference voltage Vrl and a control voltage Vl for distinguishing from the reference voltage Vrc and the control voltage Vc in the variable control circuit 320.

[0106] The variable control circuit 320 can control the inductance Lt of the power transmission coil 112f according to the relative state of the power receiving coil 212 and the power transmission coil 112. For example, in the relative state, the inductance Lt is set to Lt=L1, and in the non-relative state, it is set to Lt>L1. Therefore, in the structure of the sixth embodiment, the input impedance Z1 of the power transmission resonance circuit 110 can be reduced to Z1=Z1r in the relative state (refer to the above formula (5c)) and increased to Z1=Z1n>Z1r in the non-relative state (refer to the above formula (6)). Therefore, the sixth embodiment can also obtain the effect described in the first embodiment. In addition, as described above, when the input impedance Z1 in the non-relative state is increased by changing the size of the inductance Lt of the power transmission coil 112, the increase in the size of the power transmission coil 112 becomes a problem. On the other hand, when the input impedance Z1 in the non-opposing state is increased by changing the capacitance Ct of the power transmission resonance capacitor 116 as in the fourth and fifth embodiments, the capacitance Ct of the power transmission resonance capacitor 116 can be reduced. Therefore, the capacitance Ct of the power transmission resonance capacitor 116 can be changed without increasing the size of the power transmission resonance capacitor 116.

[0107] Furthermore, although the variable control circuit 320f has been described by taking the variable control circuit using the current sensor 322 as an example, a variable control circuit using the magnetic field sensor 322e can be applied as in the fifth embodiment.

[0108] G. Seventh Implementation Method:

[0109] In the seventh embodiment, if Fig.18 As shown, the structure of the fourth embodiment using the power transmission resonance capacitor 116d implemented as a variable capacitor is applied (see Fig.11 ) and the structure of the sixth embodiment using the power transmission coil 112f implemented by a variable coil (refer to Fig.17 ) both sides. The variable control circuit 320g includes a current sensor 322, a rectifier circuit 324, an LPF circuit 326, and voltage conversion circuits 328c and 328l. The voltage conversion circuit 328c is the same as the voltage conversion circuit 328 for outputting the control voltage Vc of the power transmission resonant capacitor 116d in the fourth embodiment, and the voltage conversion circuit 328l is the same as the voltage conversion circuit 328 for outputting the control voltage Vl of the power transmission coil 112f in the sixth embodiment. In addition, the filter circuit 120 may not be provided.

[0110] The variable control circuit 320g can control the capacitance Ct of the power transmission resonance capacitor 116d and the inductance Lt of the power transmission coil 112f according to the relative state of the power receiving coil 212 and the power transmission coil 112. Therefore, in the structure of the seventh embodiment, the input impedance Z1 of the power transmission resonance circuit 110 can be reduced to Z1=Z1r (refer to the above formula (5c)) in the relative state, and increased to Z1=Z1n>Z1r (refer to the above formula (6)) in the non-relative state. In addition, by controlling both the capacitance Ct of the power transmission resonance capacitor 116d and the inductance Lt of the power transmission coil 112f, the input impedance Z1=Z1n in the non-relative state can be further increased. Therefore, compared with the fourth and sixth embodiments, the effect described in the first embodiment can be more effectively obtained. In addition, the variation range of the capacitance of the resonance capacitor required to set the input impedance in the non-relative state to be greater than the target value and the current flowing in the power transmission resonance circuit in the non-relative state to be less than the target value can be reduced, thereby facilitating the setting of the capacitance of the resonance capacitor.

[0111] In addition, although the variable control circuit 320g is described by taking the variable control circuit using the current sensor 322 as an example, it can be changed as in the fifth embodiment (see Fig.16 ) as in the case of a variable control circuit using a magnetic field sensor 322e.

[0112] H. Eighth Implementation Method:

[0113] In the eighth embodiment, as the structure for changing the input impedance Z1 described in the first embodiment, Fig.19 As shown in FIG. 1 , a structure of a power transmission resonant capacitor 116h is applied in which the input capacitance is variable by switching a switch. Fig.19 In the Figure 1 or Figure 5 Among the components of the contactless power supply device 100 shown, the power transmission resonance circuit 110 and the variable control circuit 320h for making the capacitance Ct of the power transmission resonance capacitor 116h of the power transmission resonance circuit 110 variable are shown, and other components are omitted.

[0114] like Fig.19As shown, the power transmission resonance capacitor 116h includes a first resonance capacitor 116ha and a second resonance capacitor 116hb arranged in parallel. However, the second resonance capacitor 116hb is connected in parallel with the first resonance capacitor 116ha when the bidirectional switch 117 connected in series is turned on, and is disconnected when the bidirectional switch 117 is turned off. Therefore, the capacitance Ct of the power transmission resonance capacitor 116h becomes the capacitance Chs of the first resonance capacitor 116ha when the bidirectional switch 117 is turned off, and becomes the sum (Chs+Chl) of the capacitances Chs and Chl of the first resonance capacitor 116ha and the second resonance capacitor 116hb when the bidirectional switch 117 is turned on.

[0115] The variable control circuit 320h is basically the same as the variable control circuit 320 of the fourth embodiment including the current sensor 322 (see Fig.11 ). Alternatively, the variable control circuit 320e of the fifth embodiment including the magnetic field sensor 322e (see Fig.16 ). However, instead of the voltage conversion circuit 328 that outputs the control voltage Vc corresponding to the magnitude of the difference between the detection voltage and the reference voltage Vrc, a voltage conversion circuit 328h using a comparator that outputs the control voltage Vs corresponding to the magnitude of the detection voltage Vd relative to the threshold voltage Vth may be included. In addition, as the threshold voltage Vth, it is preferable to set it to the start threshold value Vth_on when the state changes from the non-relative state to the relative state and the bidirectional switch 117 is turned on, and to set it to the stop threshold value Vth_off when the state changes from the relative state to the non-relative state and the bidirectional switch 117 is turned off.

[0116] When the detection voltage Vd is less than the threshold voltage Vth in the non-opposite state, the voltage conversion circuit 328h outputs the control voltage Vs of the voltage that turns off the bidirectional switch 117, and when the detection voltage Vd is greater than the threshold voltage Vth in the relative state, the voltage conversion circuit 328h outputs the control voltage Vs of the voltage that turns on the bidirectional switch 117. Thus, the capacitance Ct of the power transmission resonance capacitor 116h becomes the capacitance Chs of the first resonance capacitor 116ha in the non-opposite state, and becomes the sum of the capacitances Chs and Chl of the first resonance capacitor 116ha and the second resonance capacitor 116hb in the relative state. In addition, the capacitance Chs of the first resonance capacitor 116ha and the capacitance Chl of the second resonance capacitor 116hb may be set so that the capacitance Ct=(Chs+Chl) in the relative state becomes the resonance capacitance C1 and the capacitance Ct=Chs in the non-opposite state becomes smaller than the resonance capacitance C1, and is set so that Chs<Chl.

[0117] The variable control circuit 320h can switch the capacitance Ct of the power transmission resonance capacitor 116h according to whether the power receiving coil 212 and the power transmission coil 112 are in an opposing state or a non-opposing state. Fig. 20 As shown, the variable control circuit 320h can automatically control the power supply from the contactless power supply device 100 to the power receiving device 200. Specifically, when the detection voltage Vd becomes equal to or higher than the start threshold value Vth_on as the threshold voltage Vth and the change from the non-relative state to the relative state is detected (step S10: Yes), the variable control circuit 320h turns on the switching circuit (bidirectional switch 117) (step S20), and reduces the input impedance Z1 of the power transmission resonance circuit 110 to Z1=Z1r (refer to the above formula (5c)). In this way, the power supply from the contactless power supply device 100 to the power receiving device 200 can be started. Furthermore, when the detection voltage Vd becomes lower than the stop threshold value Vth_off as the threshold voltage Vth and the change from the relative state to the non-relative state is detected (step S30: Yes), the variable control circuit 320h turns off the switching circuit (step S40), and increases the input impedance Z1 of the power transmission resonance circuit 110 to Z1=Z1n>Z1r (refer to the above formula (6)). In this way, the power supply from the contactless power supply device 100 to the power receiving device 200 can be stopped.

[0118] Thus, in the configuration of the eighth embodiment, the input impedance Z1 of the power transmission resonance circuit 110 can be reduced to Z1=Z1r (refer to the above formula (5c)) in the relative state, and can be increased to Z1=Z1n>Z1r (refer to the above formula (6)) in the non-relative state. Therefore, the effect described in the first embodiment can also be obtained in the eighth embodiment. In addition, when the input impedance Z1 in the non-relative state is increased by changing the size of the capacitance Ct of the power transmission resonance capacitor 116h, it is sufficient to reduce the capacitance Ct of the power transmission resonance capacitor 116h. Therefore, the size of the capacitance Ct of the power transmission resonance capacitor 116h can be changed without increasing the size of the power transmission resonance capacitor 116h.

[0119] In addition, as a structure of a variable control circuit for switching the bidirectional switch 117, it is possible to set not only Fig.19 The structure using the current sensor 322 shown or Fig.16 The structure using the magnetic field sensor 322e shown can also be configured to use Fig.21 The variable control circuit 320i or Fig. 22 The structure of the variable control circuit 320j is shown.

[0120] The variable control circuit 320i is a structure including a detection coil 118 arranged opposite to the power transmission coil 112. The variable control circuit 320i is a structure that detects an AC voltage generated between the terminals of the detection coil 118 according to whether the power receiving coil 212 and the power transmission coil 112 are in an opposite state or a non-opposite state as a detection voltage Vd, and switches and controls the bidirectional switch 117 according to a control voltage Vs output according to a magnitude relationship between the detection voltage Vd and the threshold voltage Vth.

[0121] The variable control circuit 320j has the following structure: the AC voltage generated between the terminals of the power transmission coil 112 corresponding to whether the power receiving coil 212 and the power transmission coil 112 are in a relative state or a non-relative state is detected as a detection voltage Vd, and the bidirectional switch 117 is switched based on the control voltage Vs output in accordance with the magnitude relationship of the detection voltage Vd relative to the threshold voltage Vth.

[0122] I. Ninth Implementation Method:

[0123] In the ninth embodiment, if Fig.23 As shown, a power transmission resonance capacitor 116k is used instead of the power transmission resonance capacitor 116h of the eighth embodiment (see Fig.19 ).in addition, Fig.23 and Fig.19 Similarly, among the components of the contactless power supply device 100, only the power transmission resonance circuit 110 and the variable control circuit 320h for making the capacitance Ct of the power transmission resonance capacitor 116k of the power transmission resonance circuit 110 variable are shown, and other components are omitted.

[0124] like Fig.23As shown, the power transmission resonance capacitor 116k includes a first resonance capacitor 116ka and a second resonance capacitor 116kb arranged in series. However, the first resonance capacitor 116ka is connected in series with the second resonance capacitor 116kb when the bidirectional switch 117 connected in parallel is turned off, and is short-circuited when the bidirectional switch 117 is turned on. Therefore, when the bidirectional switch 117 is turned on by the variable control circuit 320h in the relative state, the capacitance Ct of the power transmission resonance capacitor 116k becomes the capacitance Chl of the second resonance capacitor 116kb. On the other hand, when the bidirectional switch 117 is turned off by the variable control circuit 320h in the non-relative state, the capacitance Ct of the power transmission resonance capacitor 116k becomes the sum of the reciprocal of the capacitance Chs of the first resonance capacitor 116ka and the reciprocal of the capacitance Chl of the second resonance capacitor 116kb (Chs·Chl / (Chs+Chl)). In addition, the capacitance Chs of the first resonant capacitor 116Ka and the capacitance Chl of the second resonant capacitor 116Kb can be set so that the capacitance Ct=Chl in the relative state becomes the resonant capacitance C1 and the capacitance Ct=(Chs·Chl / (Chs+Chl)) in the non-relative state is smaller than the resonant capacitance C1, and can be set so that Chl>Chs.

[0125] The variable control circuit 320h can switch the capacitance Ct of the power transmission resonance capacitor 116k according to whether the power receiving coil 212 and the power transmitting coil 112 are in an opposing state or a non-opposing state. Fig. 20 As shown, the variable control circuit 320h can automatically control the power supply from the contactless power supply device 100 to the power receiving device 200.

[0126] As described above, in the configuration of the ninth embodiment, the input impedance Z1 of the power transmission resonance circuit 110 can be reduced to Z1=Z1r in the relative state (see the above formula (5c)), and can be increased to Z1=Z1n>Z1r in the non-relative state (see the above formula (6)). Therefore, the effect described in the first embodiment can also be obtained in the ninth embodiment. In addition, when the input impedance Z1 in the non-relative state is increased by changing the size of the capacitance Ct of the power transmission resonance capacitor 116k, it is sufficient to reduce the capacitance Ct of the power transmission resonance capacitor 116k. Therefore, the size of the capacitance Ct of the power transmission resonance capacitor 116k can be changed without increasing the size of the power transmission resonance capacitor 116k.

[0127] In addition, as described in the eighth embodiment, the variable control circuit 320e (see Fig.16) is the same as the structure of using the magnetic field sensor 322e, instead of the structure of using the current sensor 322 as the variable control circuit 320h, as the structure of the variable control circuit of the ninth embodiment. Fig.21 The variable control circuit 320i of the structure using the search coil 118 is shown as follows. Fig. 22 The variable control circuit 320j is configured to detect the voltage between the terminals of the power transmission coil 112.

[0128] J. Tenth Implementation Method:

[0129] Figure 1 The power transmission resonance circuit 110 of the contactless power supply device 100 shown in the figure is a series resonance circuit including a power transmission coil 112 and a power transmission resonance capacitor 116 connected in series, and the power receiving resonance circuit 210 of the power receiving device 200 is also a series resonance circuit including a power receiving coil 212 and a power receiving resonance capacitor 216 connected in series. Fig.24 As shown, the power transmission resonance circuit of the contactless power supply device 100 may be a power transmission resonance circuit 1101 in which the power transmission coil 112 and the power transmission resonance capacitor 116 are connected in parallel, and the power receiving resonance circuit of the power receiving device 200 may be a power receiving resonance circuit 2101 in which the power receiving coil 212 and the power receiving resonance capacitor 216 are connected in parallel.

[0130] In the state where the power receiving coil 212 is opposite to the power transmitting coil 112, the capacitance Ct of the power transmitting resonant capacitor 116 and the inductance Lt of the power transmitting coil 112 are set so that the power transmitting resonant circuit 1101 can resonate in parallel. Fig.24 ), the power transmission resonance circuit 1101 enters a resonant state, and the input impedance Z1 of the power transmission resonance circuit 110 becomes smaller to Z1=Z1r, and AC power is supplied from the power transmission circuit 130 to the power transmission coil 112, so as to supply AC power to the power receiving device 200 via the power receiving coil 212.

[0131] On the other hand, when the power receiving coil 212 is not in an opposed state with respect to the power transmitting coil 112 (see Fig.24), the resonance state of the power transmission resonance circuit 1101 collapses, and the input impedance Z1 is infinite, so the input current I1 of the power transmission resonance circuit 1101 can be made close to zero. Therefore, the power transmission resonance circuit 1101 using the parallel resonance circuit is more effective than the power transmission resonance circuit 110 using the series resonance circuit in suppressing the current from the power transmission circuit, that is, suppressing the standby power. However, in the case of the power transmission resonance circuit 1101 using the parallel resonance circuit, the leakage current ILC flows between the power transmission resonance capacitor 116 and the power transmission coil 112, so that a leakage magnetic field is generated in the power transmission coil 112. Therefore, compared with the power transmission resonance circuit 110 using the series resonance circuit, the power transmission resonance circuit 1101 using the parallel resonance circuit is disadvantageous in suppressing the leakage magnetic field.

[0132] K. Eleventh Implementation Method:

[0133] In the eleventh embodiment, application Fig.25 The power transmission resonance circuit 110m and the power receiving resonance circuit 210 shown in the embodiment 10 solve the technical problem of the leakage magnetic field of the power transmission resonance circuit 1101 using the parallel resonance circuit shown in the tenth embodiment. The power transmission resonance circuit 110m is a parallel series resonance circuit having a series capacitor 116s and a parallel capacitor 116p, the series capacitor 116s is connected in series with the power transmission coil 112, and the parallel capacitor 116p is connected in parallel with the power transmission coil 112 and the series capacitor 116s. The power receiving resonance circuit 210 is a series resonance circuit having a power transmission coil 212 and a power transmission resonance capacitor 216 connected in series. The resonance method (called "PSS method") based on the primary parallel series connection and the secondary series connection capacitor is applied to the power transmission resonance circuit 110m and the power receiving resonance circuit 210.

[0134] In the state where the power receiving coil 212 faces the power transmitting coil 112, the capacitance Cpt of the parallel capacitor 116p of the power transmitting resonant circuit 110m and the capacitance Cst of the series capacitor 116s, and the capacitance Cr of the power receiving resonant capacitor 216 of the power receiving resonant circuit 210 are set so that the power transmitting resonant circuit 110m resonates in parallel and the power receiving resonant circuit 210 resonates in series. Specifically, the following equations (7) to (9) are used for setting. In addition, the inductance Lt of the power transmitting coil 112 and the inductance Lr of the power receiving coil 212 are set to Lt=L1 and Lr=L2.

[0135] [Mathematical formula 6]

[0136]

[0137] [Mathematical formula 7]

[0138]

[0139] [Mathematical formula 8]

[0140]

[0141] In addition, k is a coupling coefficient between the power transmission coil 112 and the power reception coil 212 .

[0142] In addition, the input impedance Z1 when the power transmission coil 112 and the power reception coil 212 are in an opposed state is expressed by the following equation (10).

[0143] [Formula 10]

[0144]

[0145] In addition, Lm is the mutual inductance between the power transmission coil 112 and the power reception coil 212 , and RL is the load which equivalently represents the power reception circuit 220 and the battery 230 .

[0146] When the power transmission coil 112 and the power receiving coil 212 change from a non-opposed state to an opposed state, the input impedance Z1 of the power transmission resonance circuit 110m changes to the input impedance represented by the above equation (10), and current flows from the power transmission circuit to the power transmission resonance circuit 110m, thereby powering the power receiving device 200 from the contactless power supply device 100.

[0147] When the power transmission coil 112 and the power reception coil 212 change from the relative state to the non-relative state, the coupling coefficient k decreases, and the mutual inductance Lm decreases and becomes zero. As a result, the value of the denominator of the above formula (10) decreases toward zero, and thus the input impedance Z1 increases. As a result, the input current of the power transmission resonance circuit 110m can be suppressed, so the current from the power transmission circuit can be suppressed, that is, the standby power can be suppressed.

[0148] However, as described in the tenth embodiment, due to the parallel resonance achieved by the parallel capacitor 116 p , a leakage current flows between the parallel capacitor 116 p and the power transmission coil 112 , causing a leakage magnetic field to be generated in the power transmission coil 112 .

[0149] Therefore, in the non-relative state, it is preferable to reduce the capacitance Cst of the series capacitor 116s from the value set by the above formula (8). As a result, the impedance Zs on the coil path side shown in the following formula (11) can be increased, thereby suppressing the leakage current flowing in the power transmission coil 112 and suppressing the generation of the leakage magnetic field.

[0150] [Mathematical formula 11]

[0151]

[0152] In addition, in the non-opposite state, it is preferable to reduce the capacitance Cp of the parallel capacitor 116p from the value set by the above formula (7). As a result, the impedance Zp on the parallel capacitor path side shown in the following formula (12) can be further increased, so the input current of the power transmission resonance circuit 110m can be further suppressed. As a result, the current from the power transmission circuit, that is, the standby power, can be further effectively suppressed.

[0153] [Mathematical formula 12]

[0154]

[0155] In addition, as a method of changing the capacitance, the methods described in the second, fourth, fifth, eighth, and ninth embodiments can be used.

[0156] L. Twelfth Implementation Method:

[0157] In the twelfth embodiment, if Fig.26 As shown, a power transmission resonance circuit 110n in which a relay resonance circuit is provided to the power transmission resonance circuit 110 using the series resonance circuit shown in the first embodiment is applied, and the power transmission resonance circuit 110n includes: a power transmission resonance circuit portion having a power transmission coil 112 and a power transmission resonance capacitor 116n similar to the power transmission resonance circuit 110; and a relay resonance circuit portion having a relay coil 114 and a relay resonance capacitor 119 constituting a closed loop circuit. The relay coil 114 is provided in a positional relationship with respect to the power transmission coil 112 so as to have a certain coupling coefficient k1h.

[0158] When the power transmission coil 112 and the power receiving coil 212 are in an opposed state, the capacitance Ct of the power transmission resonance capacitor 116n of the power transmission resonance circuit 110n, the capacitance Cht of the relay resonance capacitor 119, and the capacitance Cr of the power receiving resonance capacitor 216 of the power receiving resonance circuit 210 are set so that the power transmission resonance circuit part, the relay resonance circuit part, and the power receiving resonance circuit 210 resonate. Specifically, the following equations (13) to (15) are used for setting. In addition, the inductance Lt of the power transmission coil 112 is set to Lt=L1, the inductance of the relay coil is set to Lht, and the inductance Lr of the power receiving coil 212 is set to Lr=L2.

[0159] [Mathematical formula 13]

[0160]

[0161] [Mathematical formula 14]

[0162]

[0163] [Mathematical formula 15]

[0164]

[0165] k1h is the coupling coefficient between the power transmission coil 112 and the relay coil 114 , kh2 is the coupling coefficient between the relay coil 114 and the power reception coil 212 , and K12 is the coupling coefficient between the power transmission coil 112 and the power reception coil 212 .

[0166] In addition, the input impedance Z1 when the power transmission coil 112 and the power reception coil 212 are in an opposed state is expressed by the following equation (16).

[0167] [Formula 16]

[0168]

[0169] Note that RL is a load that equivalently represents the power receiving circuit 220 and the battery 230 .

[0170] When the power transmission coil 112 and the power receiving coil 212 change from a non-opposed state to an opposed state, the input impedance Z1 of the power transmission resonance circuit 110n becomes the input impedance represented by the above equation (16), and current flows from the power transmission circuit to the power transmission resonance circuit 110n, thereby power is supplied from the contactless power supply device 100 to the power receiving device 200.

[0171] The current Iht flowing on the relay coil 114 side is expressed by the following equation (17) in the non-opposite state, and is expressed by the following equation (18) in the opposite state when the power transmission resonance circuit part, the relay resonance circuit part, and the power receiving resonance circuit 210 resonate.

[0172] [Mathematical formula 17]

[0173]

[0174] [Mathematical formula 18]

[0175]

[0176] Furthermore, Lm is the mutual inductance between the power transmission coil 112 and the power reception coil 212, and L1h is the mutual inductance between the power transmission coil 112 and the relay coil 114. V1 is the input voltage of the power transmission resonance circuit 110m.

[0177] When the power transmission coil 112 and the power reception coil 212 change from the relative state to the non-relative state, the coupling coefficient kh2 decreases and becomes zero. As a result, the value of the denominator of the above formula (16) decreases toward zero, and thus the input impedance Z1 increases. As a result, the input current of the power transmission resonance circuit 110n can be suppressed, so the current from the power transmission circuit can be suppressed, that is, the standby power can be suppressed.

[0178] However, since the current Iht represented by the above equation (17) flows in the relay coil 114 , a leakage magnetic field is generated in the relay coil 114 .

[0179] Therefore, in the non-relative state, it is preferable to reduce the capacitance Ct of the power transmission resonance capacitor 116n of the power transmission resonance circuit part from the value set by the above formula (13). Thus, by further increasing the input impedance Z1, the voltage applied to the power transmission coil 112 can be reduced. Specifically, the capacitance Ct of the power transmission resonance capacitor 116n is reduced and the denominator of the above formula (17) is increased, so that the current Iht flowing in the relay coil 114 can be suppressed, and the leakage magnetic field generated in the relay coil 114 can be suppressed. In addition, the capacitance Cht of the relay resonance capacitor 119 can also be reduced from the value set by the above formula (14). In this way, the current Iht flowing in the relay coil 114 can also be suppressed.

[0180] In addition, as a method of changing the capacitance, the methods described in the second, fourth, fifth, eighth, and ninth embodiments can be used.

[0181] M. Thirteenth Implementation Method:

[0182] In the first to twelfth embodiments, the input impedance Z1 of the power transmission resonance circuit is changed in accordance with the relative state between the power receiving coil 212 and the power transmission coil 112. Figure 5 The capacitance of the filter capacitor 122 of the filter circuit 120 and the inductance of the filter coil 124 can be changed, and the filter circuit 120 can be made into a resonant state in the relative state, and the filter circuit 120 can be made to deviate from the resonant state in the non-relative state. Specifically, the following structure can be formed: Fig. 27 As shown, the capacitance of the filter capacitor 122o and the inductance of the filter coil 124o constituting the filter circuit 120o are changed by the variable control circuit 320o.

[0183] The filter circuit 120o is a bandpass filter circuit formed by using a capacitor 122o and a coil 124o connected in series. The order of the capacitor 122o and the coil 124o can be reversed. The capacitor 122o is a variable capacitor whose capacitance is variable according to the control voltage Vco. As a variable capacitor, various general variable capacitors can be applied. The coil 124o is a variable coil whose inductance is variable according to the control voltage Vlo. As a variable coil, various general variable coils can be applied.

[0184] In addition to including voltage conversion circuits 328co, 328lo instead of the variable control circuit 320g of the seventh embodiment (see Fig.18 ) except that the variable control circuit 320h has the same structure as the variable control circuit 320g. In addition, the voltage conversion circuit 328co is the same as the voltage conversion circuit 328c except that it outputs the control voltage Vco for controlling the capacitance of the capacitor 122o based on the reference voltage Vrco. The voltage conversion circuit 328lo is the same as the voltage conversion circuit 328l except that it outputs the control voltage Vlo for controlling the inductance of the coil 124o based on the reference voltage Vrlo.

[0185] The variable control circuit 320o can control the inductance of the coil 124o of the filter circuit 120o and the capacitance of the capacitor 122o according to the relative state of the power receiving coil 212 and the power transmitting coil 112. Specifically, in the non-relative state, the inductance and capacitance are reduced to increase the input impedance of the filter circuit 120o and suppress the current from the power transmitting circuit 130. On the other hand, in the relative state, the inductance and capacitance are increased in a manner that functions as a bandpass filter. As a result, the thirteenth embodiment can also obtain the same effect as that described in the first embodiment.

[0186] In addition, although the variable control circuit 320o is described by taking the variable control circuit using the current sensor 322 as an example, it can be changed as in the fifth embodiment (see Fig.15 ) as in the case of a variable control circuit using a magnetic field sensor 322e.

[0187] In addition, a configuration may be adopted in which one of the inductance of the coil 124o of the filter circuit 120o and the capacitance of the capacitor 122o is changed, rather than both. In addition, a configuration may be adopted in which at least one of the inductance of the coil 124o of the filter circuit 120o and the capacitance of the capacitor 122o is changed, and at least one of the inductance of the power transmission coil 112 of the power transmission resonance circuit 110 and the capacitance of the power transmission resonance capacitor 116 is changed.

[0188] In addition, as described in the eighth and ninth embodiments, the following structure may be applied: a filter capacitor is formed using a plurality of capacitors and the connection of the plurality of capacitors is switched to change the capacitance of the filter capacitor. In addition, the following structure may be applied: a filter inductor is formed using a plurality of inductors and the connection of the plurality of inductors is switched to change the inductance of the filter inductor.

[0189] N. Fourteenth Implementation Method:

[0190] In the fourteenth embodiment, if Fig.28As shown, the filter circuit 120o of the thirteenth embodiment (see Fig. 27 ) and the variable control circuit 320o that controls it are replaced by the filter circuit 120p and the variable control circuit 320p that controls it.

[0191] The filter circuit 120p is an impedance filter circuit composed of a filter capacitor 122p and two filter coils 124p, 124p. The capacitor 122p is a variable capacitor whose capacitance is variable according to the control voltage Vcp. As a variable capacitor, various general variable capacitors can be applied. The coil 124p is a variable coil whose inductance is variable according to the control voltage Vlp. As a variable coil, various general variable coils can be applied.

[0192] The variable control circuit 320p includes voltage conversion circuits 328cp and 328lp instead of the variable control circuit 320o of the thirteenth embodiment (see Fig. 27 ) is the same as the variable control circuit 320o. The voltage conversion circuit 328cp is the same as the voltage conversion circuit 328co except that it outputs the control voltage Vcp for controlling the capacitance of the capacitor 122p based on the reference voltage Vrcp. The voltage conversion circuit 328lp is the same as the voltage conversion circuit 328lo except that it outputs the control voltage Vlp for controlling the inductance of the coil 124p based on the reference voltage Vrlp.

[0193] The variable control circuit 320p can control the inductance of the coil 124p of the filter circuit 120p and the capacitance of the capacitor 122p according to the relative state of the power receiving coil 212 and the power transmitting coil 112. Specifically, in the non-relative state, the inductance and capacitance are reduced to increase the input impedance of the filter circuit 120p and suppress the current from the power transmitting circuit 130. On the other hand, in the relative state, the inductance and capacitance are increased to act as an impedance filter. Therefore, in the fourteenth embodiment, the same effect as that described in the first embodiment can be obtained.

[0194] In addition, although the variable control circuit 320p is described by taking the variable control circuit using the current sensor 322 as an example, it is also possible to use the variable control circuit 320p as in the fifth embodiment (see Fig.15 ) as in the case of a variable control circuit using a magnetic field sensor 322e.

[0195] In the above structure, the structure in which both the capacitance of the capacitor 122p and the inductance of the coil 124p are controlled is described as an example, but a structure in which either one is controlled may be used. In addition, a structure in which not only at least one of the capacitance of the capacitor 122p and the inductance of the coil 124p is made variable, but also at least one of the inductance of the power transmission coil 112 of the power transmission resonance circuit 110 and the capacitance of the power transmission resonance capacitor 116 is made variable may be used.

[0196] In addition, the following structure may be applied: as described in the eighth and ninth embodiments, a plurality of capacitors are used to form a filter capacitor and the connection of the plurality of capacitors is switched to change the capacitance of the filter capacitor. In addition, the following structure may be applied: a plurality of inductors are used to form a filter inductor and the connection of the plurality of inductors is switched to change the inductance of the filter inductor.

[0197] In addition, in the thirteenth embodiment, a bandpass filter circuit is used as an example of a filter circuit structure, and in the fourteenth embodiment, an impedance filter circuit is used as an example of a filter circuit structure. However, the present invention is not limited to this, and various other filter circuits can also be applied.

[0198] O. Fifteenth Implementation Method:

[0199] In the fifteenth embodiment, if Fig.29 As shown, the series resonant power transmission resonance circuit 110 (see Fig. 27 ) is replaced by the parallel resonant power transmission resonance circuit 1101 (refer to Fig.24 In the above structure, the effect described in the first embodiment can be obtained in the same manner as in the thirteenth embodiment. In addition, the filter circuit 120o may be configured as the filter circuit 120p of the fourteenth embodiment (see Fig.28 ) and other filter circuit structures. In addition, the power transmission resonance circuit can also be replaced by Fig.25 The parallel resonant power transmission resonance circuit 110m shown.

[0200] P. Sixteenth Implementation Method:

[0201] In the above-mentioned embodiments, the contactless power supply device 100 is described by taking the mutual inductance including one power transmission resonance part as an example, but is not limited to this. Figure 30 to Figure 32 As shown, a configuration may be adopted in which a plurality of power transmission resonance parts are connected in parallel with respect to one power transmission circuit.

[0202] Fig.30 Indicates that the power transmission circuit 130 Figure 1The power transmission resonance circuit 110 shown is configured such that a plurality of the power transmission resonance circuits 110 are arranged in parallel as a power transmission resonance section. Fig.31 The configuration in which one filter circuit 120 is disposed between the power transmission circuit 130 and a plurality of power transmission resonance circuits 110 is shown. The power transmission resonance circuit 110 having the power transmission coil 112 facing the power receiving coil 212 of the power receiving resonance circuit 210 of the power receiving device 200 among the plurality of power transmission resonance circuits 110 is operated in the same manner as in the facing state described in the first embodiment, and the other power transmission resonance circuits 110 are operated in the same manner as in the non-facing state described in the first embodiment. In this way, the same effects as those described in the first embodiment can be obtained.

[0203] Fig.32 Indicates that the power transmission circuit 130 Figure 5 The filter circuit 120 and the power transmission resonance circuit 110 shown are configured in parallel in a plurality to serve as a structure of a power transmission resonance portion. In the above structure, it is also possible to make the power transmission resonance circuit 110 having the power transmission coil 112 opposite to the power receiving coil 212 of the power receiving resonance circuit 210 of the power receiving device 200 among the plurality of power transmission resonance circuits 110 operate in the same manner as the relative state described in the first embodiment, and make the other power transmission resonance circuits 110 operate in the same manner as the non-relative state described in the first embodiment. In this way, the same effect as that described in the first embodiment can be obtained. In addition, as long as the filter circuit 120 having the power transmission coil 112 opposite to the power receiving coil 212 of the power receiving resonance circuit 210 of the power receiving device 200 among the plurality of filter circuits 120 is the same as the filter circuit in the relative state described in the thirteenth and fourteenth embodiments (refer to Fig. 27 , 28 ) and the other filter circuit 120 operates in the same manner as the filter circuit in the non-relative state described in the thirteenth and fourteenth embodiments. In this way, the same effect as that described in the thirteenth, fourteenth and first embodiments can be obtained.

[0204] also, Figure 30 to Figure 32 The contactless power supply device including a plurality of power transmission resonance parts is shown. Figure 1 , Figure 5 The power transmission resonance circuit shown in the embodiment is shown as an example, but it can also be applied to the power transmission resonance circuit shown in other embodiments. Fig.32 The contactless power supply device including a plurality of power transmission resonance parts is shown. Fig. 27 , Fig.28 The filter circuit shown is illustrated as an example, but it can also be applied by taking other filter circuits as examples.

[0205] Q. Seventeenth embodiment:

[0206] like Figure 33 to Figure 35 As shown, Figure 30 to Figure 32 The contactless power supply device 100 including a plurality of power transmission resonance parts shown can be used as a contactless power supply device of a contactless power supply system for a vehicle.

[0207] Figure 33 to Figure 35 The non-contact power supply system for a vehicle shown is a power supply system that can supply power from a non-contact power supply device 100 laid along a road along a vehicle travel route RS to a vehicle (hereinafter referred to as "vehicle 200") as a power receiving device 200. Vehicle 200 is configured as an electric vehicle or a hybrid vehicle, for example. Figure 33 to Figure 35 In the figure, the x-axis direction indicates the traveling direction of the vehicle 200 along the lane of the vehicle travel route RS, the y-axis direction indicates the width direction of the vehicle travel route RS, and the z-axis direction indicates the vertical upward direction. The directions of the x, y, and z axes in other figures described later also indicate the same as those in the figure. Figure 33 to Figure 35 Same direction.

[0208] The power transmission resonance circuit 110 includes a power transmission coil 112 laid on the vehicle travel path RS and a power transmission resonance capacitor 116 (not shown) (see Figure 30 to Figure 32 ). The power transmission coils 112 of each power transmission resonance circuit 110 are arranged along the x direction, which is the direction along the lane of the vehicle travel route RS. Figure 33 to Figure 35 7 power transmission resonant circuits 110 are shown in FIG. However, the present invention is not limited thereto, and a plurality of power transmission coils 112 may be arranged in the x direction and the y direction.

[0209] The power receiving resonance circuit 210 includes a power receiving coil 212 and a power receiving resonance capacitor 216 (not shown) (see Figure 30 to Figure 32 ), at least the power receiving coil 212 is arranged at the bottom of the vehicle 200 in a manner opposite to the power transmitting coil 112 of the power transmitting resonant circuit 110.

[0210] The AC power obtained by the power receiving resonance circuit 210 is converted into DC power by the power receiving circuit 220 and charged into the battery 230 to be used as energy for driving a motor (not shown) or the like.

[0211] The contactless power supply device of the contactless power supply system for a vehicle can also obtain the same effects as those of the contactless power supply device of the above-mentioned embodiment.

[0212] Here, it is preferable that the size of the power transmission coil 112 laid on the vehicle travel route RS is set as described below.

[0213] Fig.36The figure shows the setting of supplying power to the receiving coil from all the power transmission coils (power transmission coils shown with diagonal lines) that have a portion facing the power receiving coil. As shown in the upper part of the figure, when the power transmission coil size DTx of the power transmission coil 112 along the arrangement direction, that is, the x direction, is greater than the power receiving coil size DRx of the power receiving coil 212 along the x direction, there is a case where the area of ​​the portion that is not facing the power receiving coil 212 (hereinafter referred to as "non-facing area") increases, and the leakage magnetic flux increases. On the other hand, as shown in the lower part of the figure, when the power transmission coil size DTx is smaller than the power receiving coil size DRx, the non-facing area can be reduced compared to the case in the upper part, and the leakage magnetic flux can be reduced.

[0214] in addition, Fig.37 The figure shows the setting that the receiving coil is powered only from the transmitting coil (the transmitting coil indicated by the diagonal lines) whose relative area between the receiving coil and the transmitting coil is 50% or more. As shown in the upper part of the figure, when the transmitting coil size DTx is larger than the receiving coil size DRx, Fig.36 In the same manner as shown in the figure, there is a case where the non-opposite area increases and the leakage flux increases. In addition, sometimes the area of ​​the portion where the power receiving coil 212 and the power transmitting coil 112 are opposite to each other (the relative area) decreases, and the power that the power receiving coil 212 can receive decreases. On the other hand, as shown in the lower part of the figure, when the power transmitting coil size DTx is smaller than the power receiving coil size DRx, the non-opposite area can be reduced compared to the case in the upper part, and the leakage flux can be reduced. In addition, compared to the case in the upper part, the relative area can be increased, and the power that the power receiving coil 212 can receive can be increased.

[0215] Therefore, it is preferable that the size of the power transmission coil 112, that is, the power transmission coil size DTx, is smaller than the power reception coil size DRx.

[0216] R. Other implementations:

[0217] (1) In the above embodiment, the configuration using voltage and magnetic field as physical quantities to change the capacitance of a capacitor and the inductance of a coil is described as an example, but the present invention is not limited thereto, and a capacitor whose capacitance changes in response to a physical quantity such as light, temperature, or force, or a coil whose inductance changes in response to a physical quantity such as light, temperature, or force may be used. In this case, a variable control circuit that outputs a physical quantity corresponding to the relative state of the power transmission coil and the power reception coil may be used.

[0218] (2) In the above embodiment, the case where the impedance of the power transmission resonance circuit or the filter circuit is changed is described. However, a configuration may be adopted in which the impedance of both the power transmission resonance circuit and the filter circuit is changed.

[0219] (3) In the above embodiment, the case where the power transmission coil 112 on the power transmission side and the power receiving coil 212 on the power receiving side are both single-phase is described as an example. However, it is not limited to this. The power transmission side may also be formed into a structure of a multi-phase power transmission coil. In addition, the power receiving side may also be formed into a structure of a multi-phase power receiving coil. For example, the power transmission side may be formed into a structure of a single-phase power transmission coil and the power receiving side may be formed into a structure of a multi-phase power receiving coil of two or three phases or more. In addition, the power transmission side may be formed into a structure of a multi-phase power transmission coil of two or three phases or more, and the power receiving side may be formed into a structure of a single-phase or multi-phase power receiving coil.

[0220] The control unit and the method thereof described in the present invention may also be implemented by a special-purpose computer, which is provided by constituting a processor and a memory, and the processor is programmed to perform one or more functions embodied by a computer program. Alternatively, the control unit and the method thereof described in the present invention may be implemented by a special-purpose computer, which is provided by constituting a processor composed of one or more special-purpose hardware logic circuits. Alternatively, the control unit and the method of the control unit described in the present invention may be implemented by one or more special-purpose computers, which are constituted by a combination of a processor and a memory programmed to perform one or more functions and a processor composed of one or more hardware logic circuits. In addition, the computer program may also be stored in a computer-readable non-temporary tangible storage medium as an instruction executed by a computer.

[0221] The present invention is not limited to the above-mentioned embodiments, and can be implemented by various structures within the scope of the above-mentioned purpose. For example, the technical features in each embodiment corresponding to the technical features in each form recorded in the summary of the invention can be appropriately replaced or combined to solve part or all of the above-mentioned technical problems, or to achieve part or all of the above-mentioned effects. In addition, the above-mentioned technical features can be appropriately deleted as long as they are not described as necessary structures in this specification.

Claims

1. A contactless power supply device that supplies power to a power receiving device in a contactless manner, the contactless power supply device comprising: a power transmission circuit, the power transmission circuit transmitting AC power; as well as a power transmission resonance unit, the power transmission resonance unit having a power transmission resonance circuit, the power transmission resonance circuit including a power transmission coil and a power transmission resonance capacitor, The power transmission coil constituting the power transmission resonance circuit is a variable coil having the following characteristics: (1) the value of its inductance is a resonant inductance satisfying a resonance condition in a facing state in which the power receiving coil and the power transmission coil included in the power receiving device are electromagnetically coupled and the surface of the power receiving coil and the surface of the power transmission coil are entirely overlapped; (2) the value of the inductance decreases as the power transmission coil deviates from the facing state to a facing but non-facing state in which the surface of the power receiving coil and the surface of the power transmission coil partially overlap; (3) the value of the inductance is significantly reduced compared to the resonant inductance in a non-facing state in which the power receiving coil and the power transmission coil are not electromagnetically coupled and / or the surface of the power receiving coil and the surface of the power transmission coil neither entirely overlap nor partially overlap; Or, The power transmission resonance capacitor constituting the power transmission resonance circuit is a variable capacitor set as follows: (1) its capacitance is set to a resonance capacitance that satisfies a resonance condition in a directly facing state in which a power receiving coil included in the power receiving device is electromagnetically coupled to a power transmission coil and a surface of the power receiving coil overlaps with a surface of the power transmission coil as a whole, and in a relatively but non-directly facing state in which the surfaces of the power receiving coil and the power transmission coil partially overlap as they deviate from the directly facing state, and (2) its capacitance is set to a capacitance smaller than the resonance capacitance in a non-opposite state in which the power receiving coil and the power transmission coil are not electromagnetically coupled and / or the surfaces of the power receiving coil and the power transmission coil neither overlap as a whole nor partially overlap as they deviate from the directly facing state, so that the power transmission resonance circuit deviates from the resonance state. In the facing state and the relatively non-facing state, the input impedance of the power transmission resonance circuit is set to be small by making the power transmission resonance circuit enter a resonance state, thereby supplying AC power from the power transmission circuit to the power transmission coil. In the non-opposing state, the power transmission resonant circuit is deviated from the resonant state so that the input impedance of the power transmission resonant circuit is set larger than the input impedance in the opposing state, thereby stopping the supply of AC power from the power transmission circuit to the power transmission coil.

2. The contactless power supply device according to claim 1, characterized in that: The power transmission resonance capacitor has a structure connected in series with the power transmission coil.

3. The contactless power supply device according to claim 1 or 2, characterized in that: In the non-opposing state, the capacitance of the power transmission resonance capacitor is set to be reduced.

4. The contactless power supply device according to claim 1, characterized in that: The power transmission resonance unit also has a filter circuit, the filter circuit being arranged between the power transmission circuit and the power transmission resonance circuit and including a filter coil and a filter capacitor, In the relative state, the input impedance of the power transmission resonance circuit is set to be small by bringing the power transmission resonance circuit into a resonance state, and in the non-relative state, the input impedance of the power transmission resonance circuit is set to be large by making the power transmission resonance circuit deviate from the resonance state, Or, In the relative state, the filter circuit is set so that the input impedance of the filter circuit becomes smaller by making at least the filter circuit enter a resonant state, and in the non-relative state, the filter circuit is set so that the input impedance of the filter circuit becomes larger by making at least the filter circuit deviate from the resonant state.

5. The contactless power supply device according to claim 4, characterized in that: The filter capacitor and the power transmission resonance capacitor have a structure in which they are connected in series with the power transmission coil.

6. The contactless power supply device according to claim 4 or 5, characterized in that: In the non-relative state, When the input impedance of the power transmission resonance circuit is set to be large, the capacitance of the power transmission resonance capacitor is set to be reduced. When setting is performed so as to increase the input impedance of the filter circuit, the capacitance of the filter capacitor is set to decrease.

7. The contactless power supply device according to claim 3, characterized in that: The power transmission resonance circuit includes a parallel series resonance circuit including the power transmission coil and a series capacitor connected in series with the power transmission coil and a parallel capacitor connected in parallel with the power transmission coil as the power transmission resonance capacitor. The power receiving device includes a power receiving resonance circuit including the power receiving coil and a power receiving resonance capacitor connected in series with the power receiving coil. The capacitance of the series capacitor is variable.

8. The contactless power supply device according to claim 6, characterized in that: The power transmission resonance circuit includes a parallel series resonance circuit including the power transmission coil and a series capacitor connected in series with the power transmission coil and a parallel capacitor connected in parallel with the power transmission coil as the power transmission resonance capacitor. The power receiving device includes a power receiving resonance circuit including the power receiving coil and a power receiving resonance capacitor connected in series with the power receiving coil. The capacitance of the series capacitor is variable.

9. The contactless power supply device according to claim 7 or 8, characterized in that: The capacitance of the parallel capacitor is also variable.

10. The contactless power supply device according to claim 3, characterized in that: The power transmission resonance circuit comprises: a series resonant circuit including the power transmission coil and the power transmission resonant capacitor connected in series with the power transmission coil; and a relay resonance circuit including a relay coil arranged opposite to the power transmission coil and a relay resonance capacitor connected in series with the relay coil, The power receiving device includes a power receiving resonance circuit including a power receiving resonance capacitor connected in series with the power receiving coil. The capacitance of the power transmission resonance capacitor is variable.

11. The contactless power supply device according to claim 6, characterized in that: The power transmission resonance circuit comprises: a series resonant circuit including the power transmission coil and the power transmission resonant capacitor connected in series with the power transmission coil; and a relay resonance circuit including a relay coil arranged opposite to the power transmission coil and a relay resonance capacitor connected in series with the relay coil, The power receiving device includes a power receiving resonance circuit including a power receiving resonance capacitor connected in series with the power receiving coil. The capacitance of the power transmission resonance capacitor is variable.

12. The contactless power supply device according to claim 10 or 11, characterized in that: The capacitance of the relay resonant capacitor is also variable.

13. The contactless power supply device according to claim 6, characterized in that: The filter circuit is a bandpass filter circuit, In the non-opposing state, the capacitance of the filter capacitor is made variable, thereby causing the filter circuit to deviate from a resonant state.

14. The contactless power supply device according to claim 3, characterized in that: A variable capacitor whose capacitance changes according to the input voltage is used for the capacitor whose capacitance is reduced. including a sensor for detecting the current flowing in the power transmission coil or a sensor for detecting the magnetic field generated by the power transmission coil, The capacitance of the variable capacitor is variable according to the value detected by the sensor.

15. The contactless power supply device according to claim 6, characterized in that: A variable capacitor whose capacitance changes according to the input voltage is used for the capacitor whose capacitance is reduced. including a sensor for detecting the current flowing in the power transmission coil or a sensor for detecting the magnetic field generated by the power transmission coil, The capacitance of the variable capacitor is variable according to the value detected by the sensor.

16. The contactless power supply device according to any one of claims 1, 2, 4 and 5, characterized in that: The power transmission resonance capacitor is a capacitor with reduced capacitance. A variable capacitor whose capacitance changes in accordance with a magnetic field is used for the power transmission resonance capacitor.

17. The contactless power supply device according to claim 16, wherein: The variable capacitor is disposed on a surface of the core portion along the loop-shaped wiring, on an inner circumferential side of a loop-shaped wiring wound around a core portion of the power transmission coil.

18. The contactless power supply device according to claim 3, characterized in that: The capacitance of the capacitor whose capacitance is reduced reaches a predetermined target minimum value when the facing area of ​​the power transmission coil and the power reception coil becomes zero and they become non-facing.

19. The contactless power supply device according to claim 6, characterized in that: The capacitance of the capacitor whose capacitance is reduced reaches a predetermined target minimum value when the facing area of ​​the power transmission coil and the power reception coil becomes zero and they become non-facing.

20. The contactless power supply device according to claim 16, wherein: The capacitance of the capacitor whose capacitance is reduced reaches a predetermined target minimum value when the facing area of ​​the power transmission coil and the power reception coil becomes zero and they become non-facing.

21. The contactless power supply device according to claim 3, characterized in that: The capacitance of the capacitor with reduced capacitance decreases linearly as the facing area between the power transmission coil and the power reception coil decreases.

22. The contactless power supply device according to claim 6, characterized in that: The capacitance of the capacitor with reduced capacitance decreases linearly as the facing area between the power transmission coil and the power reception coil decreases.

23. The contactless power supply device according to claim 16, characterized in that: The capacitance of the capacitor with reduced capacitance decreases linearly as the facing area between the power transmission coil and the power reception coil decreases.

24. The contactless power supply device according to any one of claims 1, 2, 4 and 5, characterized in that: When the power receiving coil is not opposed to the power transmitting coil, the inductance of the power transmitting coil is set to be reduced.

25. The contactless power supply device according to claim 3, characterized in that: When the power receiving coil is not opposed to the power transmitting coil, the inductance of the power transmitting coil is set to be reduced.

26. The contactless power supply device according to claim 6, characterized in that: When the power receiving coil is not opposed to the power transmitting coil, the inductance of the power transmitting coil is set to be reduced.

27. The contactless power supply device according to claim 4 or 5, characterized in that: The inductance of the filter coil is set to be reduced when the power receiving coil is not opposed to the power transmitting coil.

28. The contactless power supply device according to claim 6, characterized in that: The inductance of the filter coil is set to be reduced when the power receiving coil is not opposed to the power transmitting coil.

29. The contactless power supply device according to claim 27, characterized in that: A variable coil whose inductance changes according to the input voltage is used as the coil with reduced inductance. A sensor for detecting the current flowing in the power transmission coil or a sensor for detecting the magnetic field generated by the power transmission coil is included. The inductance of the variable coil is variable according to the value detected by the sensor.

30. The contactless power supply device according to claim 28, characterized in that: A variable coil whose inductance changes according to the input voltage is used as the coil with reduced inductance. A sensor for detecting the current flowing in the power transmission coil or a sensor for detecting the magnetic field generated by the power transmission coil is included. The inductance of the variable coil is variable according to the value detected by the sensor.

31. The contactless power supply device according to any one of claims 14, 15, 29 and 30, characterized in that: A sensor for detecting the magnetic field is arranged on a surface of the core along the loop-shaped wiring, on the inner circumference side of the loop-shaped wiring wound around the core of the power transmission coil.

32. The contactless power supply device according to any one of claims 1, 2, 4 and 5, characterized in that: The plurality of power transmission resonance parts are connected in parallel to the power transmission circuit.

33. The contactless power supply device according to claim 3, characterized in that: The plurality of power transmission resonance parts are connected in parallel to the power transmission circuit.

34. The contactless power supply device according to claim 6, characterized in that: The plurality of power transmission resonance parts are connected in parallel to the power transmission circuit.

35. The contactless power supply device according to claim 32, characterized in that: In a direction along the arrangement direction of the plurality of power transmission coils, a size of each of the plurality of power transmission coils is smaller than a size of the power reception coil.

36. The contactless power supply device according to claim 33 or 34, characterized in that: In a direction along the arrangement direction of the plurality of power transmission coils, a size of each of the plurality of power transmission coils is smaller than a size of the power reception coil.

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