JP6628273B2 - Non-contact power transmission device - Google Patents

Description

The present invention is, one side (the side for supplying power: primary side): about non-contact power transmission apparatus that sent the power in a non-contact manner from the other side (secondary side side to which electric power is supplied).

  Non-contact charging technology that uses electromagnetic induction to contactlessly transfer power from one side (the side that supplies power: the primary side) to the other side (the side that receives power: the secondary side) And a non-contact charging system using magnetic resonance. As a power transmission technique using a magnetic resonance method, a non-contact power supply system disclosed in Patent Document 1 is known. The technique disclosed in Patent Literature 1 discloses a technique in which a plurality of coils are arranged in parallel as primary and secondary coils, and power is transmitted from the primary coil to the secondary coil by using a magnetic resonance method. It has a transmission circuit.

  By arranging a plurality of coils in parallel as the primary and secondary coils, the interval between the primary coils (the width of the primary coil) and the interval between the secondary coils (the width of the secondary coil) Can be increased to some extent. Therefore, for example, an environment that can be conveniently applied to a charging device for an electric vehicle and a bidirectional power transmission device between an electric vehicle and a house can be constructed.

  On the other hand, as an application of non-contact charging technology for transmitting electric power from the primary side to the secondary side in a non-contact manner, it is applied to power supply to a power consuming member installed at a high place, for example, to power supply to an aviation obstacle light of a power transmission tower. It is possible. By applying the non-contact charging technology, power can be supplied while securing an electrical insulation distance. Heretofore, when a technology for supplying electric power in a non-contact manner to supply power to an aviation obstacle light of a power transmission tower is applied, an induced current from an overhead ground wire, a storage battery with solar power generation, and the like have been used. However, when an induced current from an overhead ground wire is used, there is a problem that a voltage rise occurs due to a lightning strike, and when a storage battery with a photovoltaic power generation is used, work at a high place for maintenance and inspection of the storage battery is required. I will.

  In order to reduce voltage rise and work at high places, it is conceivable to provide a plurality of coils in parallel as a primary side coil and a secondary side coil in the magnetic resonance system, and to supply power to a high place without contact. In this case, the width of the primary coil and the width of the secondary coil can be increased to some extent, but the distance between the end of the primary coil and the end of the secondary coil cannot be increased. . In other words, the distance between the end of the primary coil and the end of the secondary coil cannot be increased, and power must be transmitted in a non-contact manner over a long distance from near the ground to near the top of the transmission tower. It is difficult. For this reason, a non-contact power transmission device is not applied to power supply up to the vicinity of the uppermost part of a structure such as a power transmission tower in which a power supply device must be provided near the ground with a high structure. It is the current situation.

JP 2014-217117 A

The present invention has been made in view of the above situation, and includes one coil member on one side (a side on which power is supplied: a primary side) and another coil member on the other side (a side on which power is supplied: a secondary side). It is an object of the present invention to provide a non-contact power transmission device including a non-contact power transmission circuit capable of increasing a distance.

According to a first aspect of the present invention, there is provided a non-contact power transmission device according to the present invention, wherein a closed circuit is formed by one coil on one side and one capacitor connected in parallel to the one coil . It is installed on the ground side as one coil member, and the other coil on the other side and the other capacitor connected in parallel with the other coil form a closed circuit, and installed on the topmost part of the power transmission tower, the other coil member On the other hand, a relay coil and a relay capacitor connected in parallel to the relay coil form a closed circuit to form a relay coil member, and the relay coil member is provided between the one coil member and the other coil member. At least one is disposed as a non-contact power transmission circuit, wherein the non-contact power transmission circuit is connected to a DC power supply, and converts a DC output voltage of the DC power supply into an AC voltage, and converts the converted AC voltage. A power converter connected to the one coil and driven as an inverter so that a voltage is applied to the other coil; and a DC output connected to the other coil and applied to the AC voltage through the other coil. And a power converter that is driven as a converter that converts the voltage into a voltage and applies a DC output voltage to a DC load.

In the present invention according to claim 1, in the magnetic resonance system, at least one relay coil member is disposed between the one coil member and the other coil member, so that the one coil member is connected to the other coil member via the relay coil. One coil member on one side (power supply side: primary side) and the other side (power supply side: secondary side) based on the total coil distance between the coil members. The distance from the other coil member can be ensured.
Then, power can be transmitted via the inverter and the converter in a state where the distance between the one coil member on one side (primary side) and the other coil member on the other side (secondary side) is ensured.

  As a result, it is possible to increase the distance between one coil member on one side (primary side) and the other coil member on the other side (secondary side). By arbitrarily selecting the number of relay coil members, the distance between the one coil member and the other coil member can be set to any desired distance.

The contactless power transmission apparatus of the present invention according to claim 2, in the non-contact power transmission apparatus according to claim 1, wherein the relay coil member is disposed two or more, the one coil element and the relay coil member , The distance between the relay coils, and the distance between the relay coil member and the other coil member are set to the same distance.

  In the present invention according to claim 2, the distance between the one coil member and the relay coil member, the distance between the relay coils, and the distance between the relay coil member and the other coil member become equal, and the loss (conductive wire loss) of each coil is evenly reduced. can do.

The non-contact power transmission apparatus of the present invention according to claim 3, in the non-contact power transmission apparatus according to claim 1 or claim 2, wherein the relay coil member, at least the relay coil is held in the insulator It is characterized by having.

  According to the third aspect of the present invention, since the relay coil is held by the insulator to form the relay coil member, electrical insulation between the one coil member and the other coil member can be reliably ensured.

The non-contact power transmission apparatus of the present invention according to claim 4, in the non-contact power transmission apparatus according to claim 3, wherein the relay coil is the one coil, there is no directionality with respect to the other coil It is a coil.

  In the present invention according to claim 4, since the directionality of the relay coil held by the insulator does not matter, there is no restriction on the installation direction of the member holding the relay coil with the insulator, and the handling is easy.

The contactless power transmission device of the present invention increases the distance between one coil member on one side (the side that supplies power: the primary side) and the other coil member on the other side (the side that receives power: the secondary side). It is possible to provide a non-contact power transmission device including a non-contact power transmission circuit capable of performing the following.

1 is a schematic system diagram of a wireless power transmission device including a wireless power transmission circuit according to an embodiment of the present invention. FIG. 3 is an explanatory view of a coil arrangement. FIG. 2 is an equivalent circuit diagram of the wireless power transmission circuit according to one embodiment of the present invention. It is an equivalent circuit diagram of the non-contact electric power transmission circuit concerning a comparative example. It is a table | surface figure explaining a coupling coefficient. 5 is a graph showing a frequency characteristic of an input impedance. It is a graph showing power transmission efficiency. It is a graph explaining the loss situation of a coil. It is an explanatory view of an example of application of a non-contact electric power transmission device concerning one example of the present invention.

  The configuration of the wireless power transmission circuit and the wireless power transmission device according to the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic diagram illustrating the overall outline of a non-contact power transmission device including a non-contact power transmission circuit according to one embodiment of the present invention. FIG. 2 is a diagram illustrating one coil member, the other coil member, and a relay coil member. The situation of the arrangement is shown.

  As shown in FIG. 1, a non-contact power transmission device 1 includes a primary-side facility 3 that is a facility (power supply device) on one side (a side that supplies power: a primary side) including a one-side coil member 2 and a coil on the other side. A secondary-side facility 6 which is a facility on the other side (a side to which electric power is supplied: a secondary side) provided with the member 5 is provided.

  As an example of the secondary facility 6, an aviation obstruction light of a power transmission tower is applied, for example. As will be described in detail later, by installing a power supply as the primary-side equipment 3 below the transmission tower, the power supply to the aviation obstruction light installed above the transmission tower, which is a high place, is supplied by a ground power supply. From an insulating part.

  As shown in FIG. 2, one-sided coil member 2 is configured by forming a closed circuit by one-sided coil 4 and one-sided capacitor 8 connected in parallel to one-sided coil 4. Further, the other coil member 5 is configured such that a closed circuit is formed by the other coil 7 and the other capacitor 9 connected in parallel to the other coil 7.

  As shown in FIG. 1, the primary-side facility 3 is provided with a DC power supply 11, the DC power supply 11 is connected with an inverter 12 as one power converter, and the inverter 12 is connected with one coil of the one coil member 2. Have been. The inverter 12 is driven such that the DC output voltage of the DC power supply 11 is converted into an AC voltage, and the AC voltage converted via one coil 4 is applied to the other coil 7.

  The secondary facility 6 is provided with a load 15 (DC load: for example, an aviation obstruction light), and the load 15 is connected to a rectifier 16 as the other power converter, and the rectifier 16 is connected to the other coil 7. . The rectifier 16 is driven as a converter that converts an AC voltage applied via the other coil 7 to a DC output voltage and applies the DC output voltage to the load 15.

  As shown in FIGS. 1 and 2, two relay coil members 21 are arranged between the one coil member 2 and the other coil member 5. The relay coil member 21 includes a relay coil 22 and a relay capacitor 23 connected in parallel to the relay coil 22 to form a closed circuit. At least one relay coil member 21 may be provided, and three or more relay coil members 21 may be provided. Adjacent coil members (coils) constitute a resonance circuit.

  Since the relay coil member 21 is arranged between the one coil member 2 and the other coil member 5, in the magnetic resonance system, a coil current is secured from the one coil member 2 to the other coil member 5 via the relay coil 22, A distance D between one coil member 2 on the primary side (the side on which power is supplied) and the other coil member 5 on the secondary side (the side on which power is supplied) is secured by the total distance between the coil members. Can be.

  For this reason, it is possible to increase the distance D between the one coil member 2 on the primary side and the other coil member 5 on the secondary side. By arbitrarily selecting the number of relay coil members 21, the distance D between one coil member 2 and the other coil member 5 can be set to any desired distance.

  As shown in FIG. 2, the distance S between the one coil member 2 and the relay coil member 21, the distance S between the relay coil members 21, and the distance S between the relay coil member 21 and the other coil member 5 are the same distance. The distance D between the primary coil member 2 on the primary side and the secondary coil member 5 on the secondary side is set to three times (3S) the distance S.

  On the other hand, since the distance S between the coil member 2 and the relay coil member 21, the distance S between the relay coil members 21, and the distance S between the relay coil member 21 and the other coil member 5 are equalized, the loss (conductor loss) of each coil is equalized. Can be

  Although not shown in the drawings, the relay coil 22 and the relay capacitor 23 of the relay coil member 21 are configured as members that are covered with an insulator (for example, an insulator). Note that concrete, glass, styrene foam, or the like can be used as the insulator. Since the relay coil 22 is held by the insulator to form the relay coil member 21, electrical insulation between the one coil member 2 and the other coil member 5 can be reliably ensured.

  The relay coil 22 is formed of a coil having no directivity with respect to the one coil 4 and the other coil 7. For this reason, regardless of the directionality of the relay coil held by the insulator (for example, an insulator), there is no restriction on the installation direction of the member in which the relay coil 22 is covered and solidified, and the handling is easy.

  In the non-contact power transmission device 1 including the non-contact power transmission circuit having the above configuration, the DC output voltage from the DC power supply 11 is converted into an AC voltage by the inverter 12, and the converted AC voltage is transmitted through the one coil 4. The voltage is applied to the other coil 7 via the relay coil 22. On the other hand, the AC voltage applied to the coil 7 is converted by the rectifier 16 into a DC output voltage, and the DC output voltage is applied to the load 15. Thereby, the power from the DC power supply 11 is supplied to the load 15 in a non-contact manner by the magnetic resonance method.

  In the non-contact power transmission device 1 including the above-described non-contact power transmission circuit, the relay coil member 21 is disposed between the one coil member 2 and the other coil member 5, so that the DC power can be maintained in a state where electrical insulation is secured therebetween. The primary one-sided coil member 2 having the power supply 11 and the secondary-side other coil member 5 having the load 15 can be arranged.

  Thereby, the distance D between the one coil member 2 and the other coil member 5 can be increased. By arranging the relay coil members 21 in an arbitrary number, the distance D between the one coil member 2 on the primary side and the other coil member 5 on the secondary side can be set to any desired distance.

  3 to 8, the state of the electric coupling coefficient between the coils of the one coil member 2, the relay coil member 21, and the other coil member 5 when the relay coil member 21 is introduced, and the power transmission The situation of efficiency and the situation of power transmission loss will be described.

  FIG. 3 shows the state of an equivalent circuit of a non-contact transmission circuit including two relay coil members 21. As a comparative example, FIG. 4A shows the state of an equivalent circuit of a non-contact transmission circuit without the relay coil member 21, and FIG. 4B shows a non-contact transmission circuit with one relay coil member 21. Of the equivalent circuit of FIG. FIG. 5 is a table illustrating the coupling coefficient between the coils in the equivalent circuits of FIGS. 3 and 4, FIG. 6 is the frequency characteristic of the input impedance in the equivalent circuits of FIGS. 3 and 4, and FIG. 8 shows the state of power transmission efficiency in the equivalent circuits of FIGS. 3 and 4, and FIG. 8 shows the state of coil loss in the equivalent circuits of FIGS.

As shown in FIGS. 3 and 4, in a circuit for transmitting power from the DC power supply 11 to the load 15, the self-inductance of each coil (one coil 4, the relay coil 22, and the other coil 7) is L0 _{, L 1, L 2, L 3} ( e.g., each about 53.30MyuH) and, as the winding resistance of each coil _{r 0, r 1, r 2} , r 3 ( e.g., each 0.08Omu), a resonance capacitor C _0, C _1, C _2, C ₃ (for example, each 1 μF). Also the coupling coefficient between the coils and _{k 01, k 20, k 12} , k 23, k 30, k 31.

  The input impedance and the power transmission efficiency as viewed from the DC power supply 11 are given based on the relationship between the voltage applied to the coil and the current flowing through the coil, and the mutual inductance can be derived using the coupling coefficient and the self-inductance. . The loss of each coil can be derived from the value of the current and the amount of heat generated based on the winding resistance of the coil.

  The coupling coefficient between the coils will be described with reference to FIG.

On the other hand the coupling coefficient _{k 01} between the coil adjacent to the coil 4, if no coil (FIG. 4 (a)), 1 case of coil (FIG. 4 (b)), when the second coil (3) In each case, it is 0.23.

1 coil (FIG. 4 (b)) the coupling coefficient k ₂₀ between one coil 4 and the other coil 7 spaced between one _{case, 2} coils between one and one coil 4 in the case of (3) coupling coefficient k ₂₀ between the relay coil 22 spaced are both 0.09.

The coupling coefficient k ₁₂ between the relay coil 22 and the other coil 7 in the case of one coil (FIG. 4B), and the coupling coefficient between the relay coil 22 and the other coil 7 in the case of two coils (FIG. 3) k ₁₂ are all made with 0.23.

The two coil coupling coefficient _{k 23} between the relay coil 22 and the other coil 7 in the case of (3) has a 0.23. Coupling coefficient k ₃₀ between the second coil while the other coil 7 spaced between the coils 4 and two cases (Figure 3) is 0.03, the relay coil 22 when the second coil (3) coupling factor k ₃₁ in between the other coil 7 spaced between one and has a 0.09.

As described above, the coupling coefficient _{k 01} is 0.23, the coupling coefficient _{k 12} between between the relay coil 22 between the other hand coil 4 in this embodiment and the relay coil 22 is 0.23, the relay coil 22 and the other coupling coefficient _{k 23} between the coil 7 has a 0.23. Further, when the relay coil 22 is one, whereas the coupling coefficient _{k 01} between the coil 4 and the relay coil 22 is 0.23, the coupling coefficient _{k 12} 0.23 between the relay coil 22 and the other coil 7 Has become.

  That is, it can be seen that the coupling coefficient between adjacent coils is 0.23. It can be seen that the coupling coefficient between the coils separated by one is 0.09, and the coupling coefficient between the coils separated by two is 0.03.

  Therefore, in the non-contact power transmission device 1, even if the relay coil member 21 is interposed, the coupling coefficient between adjacent coils maintains a sufficient value (for example, 0.23) necessary for power transmission. You can see that. That is, in the non-contact power transmission device 1 of the present embodiment, power can be transmitted from the DC power supply 11 to the load 15 even with the relay coil member 21 interposed.

  The frequency characteristics of the input impedance will be described with reference to FIG. 6, and the transmission efficiency of power when switching is performed in accordance with the peak of the input impedance will be described with reference to FIG.

As shown by the dotted line in FIG. 6, present in the vicinity of the peak f _a is approximately 19.60kHz of the input impedance in the case where there is no relay coil 22, as indicated by one-dot chain lines in FIG. 6, the relay coil 22 is one present and present in the vicinity peak f _b of the input impedance is approximately 23.10kHz if are, as shown by the solid line in FIG. 6, the input impedance in the case of this embodiment the relay coil 22 is present twice peak _{f c} is present in the vicinity of 21.30KHz.

  That is, it can be seen that the peak of the input impedance exists between 14 kHz and 24 kHz even when the relay coil member 21 is interposed.

  The switching frequency was set according to the peak of the input impedance, the input power and the output power were measured, and the transmission efficiency was confirmed. When the relay coil 22 is not provided, the result is indicated by a dotted line connecting □ marks in FIG. 7, and when one relay coil 22 is present, the result is indicated by a dashed line connecting the X marks in FIG. In the case of the present embodiment in which two exist, the result is indicated by a solid line connecting the circles in FIG.

  Although the efficiency is slightly higher without the relay coil 22, the efficiency gradually increases up to about 750 W in any case, and when the output exceeds about 1000 W, the high efficiency is maintained without lowering the efficiency. I have.

  That is, it is shown that even if one or two relay coil members 21 are interposed, a high transmission efficiency is maintained when the output exceeds a predetermined output. Therefore, even if a plurality of relay coils 22 exist, that is, even if the distance D between the one coil member 2 and the other coil member 5 is increased, high transmission efficiency can be maintained.

  The state of loss of each coil will be described with reference to FIG. As described above, the loss of the coil is derived from the heat value of each coil.

  In FIG. 8, No. 1 (open) indicates one coil 4, No. 2 (dot), No. 3 (oblique line) indicates the relay coil 22, and No. 4 (black) indicates the other coil 7.

  When there is no relay coil 22, as shown on the left side of FIG. 8, of the total loss of No. 1 (open) and No. 4 (filled black), the loss of one coil 4 of No. 1 (open) accounts for about 80%. ing.

  When there is one relay coil 22, as shown in the center of FIG. 8, the total loss of No. 1 (open), No. 2 (dot) and No. 4 (black) hardly increases, and the relay coil 22 of No. 2 (dot) does not increase. Is larger than the other coil 7 of No1 (open) and the other coil 7 of No4 (black).

  When two relay coils 22 are used in the present embodiment, as shown on the right side of FIG. 8, the total loss of No. 1 (open), No. 2 (dot), No. 3 (oblique), and No. 4 (filled) hardly increases. , No. 1 (white), the loss of the coil 4 is slightly larger, but the losses of the relay coils 22 of No. 2 (dots) and No. 3 (hatched) and the other coil 7 of No. 4 (black) are substantially the same.

  That is, even if one or two relay coil members 21 are interposed, the total loss (heat loss) from one coil 4 to the other coil 7 hardly increases. Then, the total heat loss from the one coil 4 to the other coil 7 is almost equally distributed to the plurality of coils. Therefore, even if the relay coil member 21 is provided to increase the distance D between the one coil member 2 and the other coil member 5, the total heat loss hardly increases, and the heat generation of one relay coil 22 is suppressed. be able to.

  As described above, in the non-contact power transmission device 1 according to the present embodiment, even when the relay coil member 21 is interposed, the coupling coefficient between adjacent coils maintains a sufficient value necessary for power transmission, Even with the coil member 21 interposed, power can be transmitted from the DC power supply 11 to the load 15. And even if the relay coil member 21 is interposed, high transmission efficiency is maintained, the total heat loss from the one coil 4 to the other coil 7 hardly increases, and the heat loss is distributed almost equally to the plurality of coils. As a result, heat generation per coil can be suppressed.

  For this reason, even if the distance D between the one coil member 2 and the other coil member 5 is increased, high transmission efficiency can be maintained, and power can be transmitted in a state in which heat generation of the plurality of coils is suppressed. Therefore, by using the non-contact power transmission device 1 of this embodiment, the one coil member 2 on the primary side (supply side) and the other coil member 5 on the secondary side (supply side) are connected. The distance can be increased by an arbitrary length.

  An application example of the wireless power transmission device 1 according to the present embodiment will be described with reference to FIG. FIG. 9 shows a concept of a situation where the non-contact power transmission device is applied to power supply to an aviation obstacle light of a power transmission tower.

  An aviation obstruction light is provided at the top of the power transmission tower, and the aviation obstruction light emits light of a predetermined color or blinks repeatedly. When supplying power to an aircraft obstacle light, it is conceivable to use an induced current from an overhead ground wire or a storage battery with photovoltaic power generation.However, when an induced current from an overhead ground wire is used, as described above, the voltage due to lightning When a storage battery with photovoltaic power generation is used, work at a high place for maintenance and inspection of the storage battery is required.

  As shown in the figure, the primary equipment 3 is installed at a site above the power transmission tower 31, the secondary equipment 6 is installed at the uppermost part of the power transmission tower 31, and the load 15 of the secondary equipment 6 is connected to an aviation obstacle. Operate as a light. The transmission tower 31 between the primary facility 3 and the secondary facility 6 is provided with an appropriate number of relay coil members 21. That is, the distance between the primary facility 3 and the secondary facility 6 is long, and power can be transmitted.

  Thereby, the power supply device as the primary equipment 3 is installed under the power transmission tower, and the power of the DC power supply of the primary equipment 3 is supplied to the secondary equipment 6 which is the power consuming member installed at the upper part of the power transmission tower. It can be supplied to the load 15 (aviation obstruction light). Since the relay coil member 21 is disposed at a predetermined interval between the primary equipment 3 and the secondary equipment 6, an electrical insulation distance can be secured by interposing an insulating part, Electric power can be supplied to the aviation obstacle light, which is the load 15, while suppressing the effects of lightning strikes and the like.

  In other words, by inserting a plurality of relay coils at equal intervals between the power transmitting and receiving coils, it is possible to secure an electrical insulation distance, and to reduce the induced current from the overhead ground wire, the storage battery with solar power generation, and the like. With respect to the technology used, the effect of the voltage increase due to the lightning strike can be suppressed, and the maintenance cost of the power transmission tower 31 can be reduced.

  The non-contact power transmission device 1 described above can be applied to power supply to a vehicle that requires power, such as an electric vehicle.

  For example, as a configuration of the power supply place, the primary facility 3 and one relay coil member 21 are installed, and the vehicle is equipped with the secondary facility. When the vehicle moves to a predetermined position (for example, immediately above the relay coil member 21), power is transmitted from the primary facility 3 to the secondary facility 6 via the relay coil member 21.

  When power is supplied to a vehicle with a high vehicle height using the same equipment, the relay coil member 21 is added. As a result, power can be supplied even when the distance between the primary facility 3 and the secondary facility 6 is long, so that power can be transmitted to a vehicle having a high vehicle height.

  Although the non-contact power transmission circuit in the above-described embodiment has been described with an example in which the DC power supply 11 supplies power to the load 15 in one direction, the circuit of the power conversion device (the inverter 12 and the rectifier 16) is appropriately changed. By doing so, it is possible to provide a device that transmits power bidirectionally.

  The present invention relates to a non-contact power transmission circuit and a non-contact power transmission device that transmit power from one side (a side that supplies power: a primary side) to another side (a side to which power is supplied: a secondary side) in a non-contact manner. Can be used in industrial fields.

DESCRIPTION OF SYMBOLS 1 Non-contact power transmission device 2 One coil member 3 Primary equipment 4 One coil 5 The other coil member 6 Secondary equipment 7 The other coil 8 One capacitor 9 The other capacitor 11 DC power supply 12 Inverter 15 Load 16 Rectifier 21 Relay coil member 22 Relay Coil 23 Relay capacitor 31 Transmission tower

Claims (4)

Forming a closed circuit with one coil on one side and one capacitor connected in parallel to the one coil , installed on the ground side of the power transmission tower as one coil member,
While forming a closed circuit with the other coil on the other side and the other capacitor connected in parallel to the other coil, it is installed at the uppermost part of the power transmission tower to serve as the other coil member,
Forming a closed circuit with a relay coil and a relay capacitor connected in parallel to the relay coil to form a relay coil member,
Between the one coil member and the other coil member, at least one of the relay coil members is arranged as a non-contact power transmission circuit,
The non-contact power transmission circuit,
A DC power supply is connected, the DC output voltage of the DC power supply is converted to an AC voltage, and the one coil is connected so that the converted AC voltage is applied to the other coil, and is driven as an inverter. Equipment and
And a second power converter that is connected to the other coil, converts an AC voltage applied through the other coil into a DC output voltage, and is driven as a converter that applies the DC output voltage to a DC load. Characteristic non-contact power transmission device. The wireless power transmission device according to claim 1,
Two or more relay coil members are arranged,
The distance between the one coil member and the relay coil member, the distance between the relay coils, and the distance between the relay coil member and the other coil member are set to the same distance. . The wireless power transmission device according to claim 1 or 2,
The relay coil member, wherein at least the relay coil is held by an insulator. The wireless power transmission device according to claim 3,
The relay coil is a coil having no directivity with respect to the one coil and the other coil.

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