JP2016012614A - Coil unit and power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil unit and a power supply system capable of reducing the generation of heat.SOLUTION: The supply of power is performed from a power supply coil 23 to a power reception coil 33 in a non-contact manner. On the side opposite to the power reception coil 33 of the power supply coil 23, a braided sheet 35 is arranged as a shield part. The braided sheets 25, 35 are provided in a sheet shape by weaving a Litz wire formed by twisting a plurality of copper wires, each one of which is insulated and covered.

Description

  The present invention relates to a coil unit that receives or supplies electric power in a non-contact manner and a power supply system having the coil unit.

  In recent years, attention has been focused on wireless power feeding without using a power cord or a power transmission cable as a power feeding system for feeding power to a battery mounted on a hybrid vehicle or an electric vehicle. One of the wireless power feeding techniques is known as a magnetic resonance type (Patent Documents 1 and 2).

  In this magnetic resonance type power supply system, one of a pair of resonance coils (= coils) that electromagnetically resonate with each other is installed on the ground of the power supply equipment, and the other is mounted on the vehicle, and the resonance coil is installed on the ground of the power supply equipment. Power is supplied in a non-contact manner to the resonance coil mounted on the vehicle.

  The power supply system described above has an advantage that power can be supplied wirelessly even if there is a certain distance between the pair of resonance coils. However, since there is a distance between the pair of resonance coils, there is a risk that large electromagnetic noise leakage may occur in the vicinity. Therefore, it has been considered to provide a conductive copper plate shield in a part of the case that houses the resonance coil or in the case.

JP 2008-87733 A JP 2012-200032 A

  The copper plate shield described above is disposed close to the resonance coil in terms of space. For this reason, there exists a problem that an eddy current flows into a copper plate shield by the magnetic field from a resonance coil, and it heats.

  Then, this invention makes it a subject to provide the coil unit and electric power feeding system which can reduce heat_generation | fever.

  The invention according to claim 1, which has been made in order to solve the above-mentioned problems, includes a coil that supplies power to or receives power from a counterpart coil in a non-contact manner, and a conductive shield that covers the side of the coil opposite to the counterpart coil. A shield unit, wherein the shield part is composed of a braided sheet knitted with a litz wire formed by twisting a plurality of conductive wires, each of which is insulated and coated, in a sheet shape It exists in the coil unit characterized by having.

  According to a second aspect of the present invention, the braided sheet is provided at a sheet body provided by braiding a plurality of litz wires, and at an edge of the plurality of sheet bodies, and the plurality of litz wires are electrically connected to each other. The coil unit according to claim 1, further comprising a conductive member.

  The invention described in claim 3 is a power feeding system having a power feeding unit provided on the ground and a power receiving unit provided on a vehicle, wherein the power receiving unit receives the power transmitted from the power feeding unit in a contactless manner. And at least one of the said electric power feeding part or the said electric power receiving part exists in the electric power feeding system characterized by having the coil unit of Claim 1 or 2.

  As described above, according to the first and third aspects of the invention, the shield part is composed of a braided sheet knitted with a litz wire, so that the frequency of the eddy current flowing through the shield part is high. Also, the resistance value can be kept low, and the temperature rise at the shield part can be suppressed.

  According to the second aspect of the present invention, since the plurality of litz wires are electrically connected to each other by the conductive member provided at the edge of the sheet main body, only one place of the conductive member is connected to the ground. Easily set multiple Litz wires to ground potential.

It is a figure which shows schematic structure of the electric power feeding system of one Embodiment of this invention. It is a figure explaining arrangement | positioning of the electric power feeding unit with which the electric power feeding system of FIG. FIG. 3 is a schematic exploded perspective view of a power feeding unit and a power receiving unit in FIG. 2. FIG. 4 is a top view of the braided sheet shown in FIG. 3. It is a graph which shows the increase rate of the resistance with respect to the frequency of the conventional copper plate shield and the braided sheet of this embodiment. It is a graph which shows temperature with respect to elapsed time when an eddy current generate | occur | produces in the conventional copper plate shield and the braided sheet | seat of this embodiment, respectively. It is a top view of the braided sheet in other embodiment. It is a top view of the braided sheet in other embodiment.

  Hereinafter, a power supply system according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a diagram illustrating a schematic configuration of a power feeding system according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the arrangement of the power supply unit and the power reception unit included in the power supply system of FIG. FIG. 3 is a schematic exploded perspective view of the power feeding unit and the power receiving unit of FIG. In FIG. 3, the reference numerals of the parts constituting the power receiving unit are shown in parentheses. 4 is a top view of the braided sheet shown in FIG.

  The power feeding system of this embodiment supplies electric power to the vehicle from the ground side in a non-contact manner using a magnetic field resonance method. A method other than the magnetic field resonance method may be used as long as power is transmitted by electromagnetically coupling the power feeding side and the power receiving side.

  First, the configuration of the power feeding system 1 will be described. As shown in FIG. 1, the power feeding system 1 includes a power feeding device 20 as a power feeding unit arranged on the ground G (shown in FIG. 2) and a power receiving unit as a power receiving unit arranged in a vehicle V (shown in FIG. 2). Device 30. As shown in FIG. 2, the vehicle V includes a drive unit DRV having an engine and a motor, and a power battery BATT that supplies electric power to the motor.

  As shown in FIG. 1, the power feeding device 20 includes a high-frequency power source 21, a power feeding unit 22 as a coil unit, a matching unit 27, and a control unit 28. The high frequency power source 21 generates, for example, high frequency power from a commercial power source and supplies it to a power supply unit 22 described later.

  As shown in FIG. 3, the power supply unit 22 includes a power supply coil 23 as a coil, a power supply capacitor body 24, a braided sheet 25 for preventing electromagnetic noise leakage, and a box-type power supply case 26 that accommodates these. ,have. The power supply unit 22 is installed on the ground G as shown in FIG. The power supply unit 22 may be embedded in the ground G.

  The feeding coil 23 and the feeding capacitor body 24 are connected in series to each other to form a resonance circuit that resonates at a predetermined resonance frequency. In the present embodiment, the feeding coil 23 and the feeding capacitor body 24 are connected in series, but may be connected in parallel.

  The matching unit 27 is a circuit for matching the impedance between the high-frequency power source 21 and the resonance circuit including the feeding coil 23 and the feeding capacitor body 24. The control unit 28 includes a microcomputer having a ROM, a RAM, and a CPU, and controls the entire power supply apparatus 20. For example, the control unit 28 performs on / off control of the high-frequency power source 21 in response to a request for power transmission.

  The power receiving device 30 includes a power receiving unit 32 as a coil unit and a rectifier 38. As shown in FIG. 3, the power receiving unit 32 includes a power receiving coil 33 as a coil, a power receiving capacitor body 34, a braided sheet 35 for preventing leakage of electromagnetic noise, and a box-shaped power receiving case 36 that accommodates these. ,have. The power receiving unit 32 is attached to the lower surface of the vehicle V as shown in FIG.

  The power receiving coil 33 and the power receiving capacitor body 34 are connected in series to form a resonance circuit that resonates at the same resonance frequency as that of the power supply unit 22. In the present embodiment, the power receiving coil 33 and the power receiving capacitor body 34 are connected in series, but may be connected in parallel.

  The rectifier 38 converts the high frequency power received by the power receiving unit 32 into DC power. For example, a load L such as a charging unit used for charging a power battery BATT mounted on the vehicle V is connected to the rectifier 38.

  In the power supply system 1 described above, when a charging operation for the power battery BATT of the parked vehicle V is input at the power supply facility and a request for power transmission to the vehicle V is generated, the control unit 28 turns on the high-frequency power source 21. To generate high-frequency power. When the high frequency power is supplied to the power supply unit 22, the power supply unit 22 and the power receiving unit 32 magnetically resonate, and the high frequency power is transmitted from the power supply unit 22, and the high frequency power is received by the power receiving unit 32. The The high frequency power received by the power receiving unit 32 is converted into DC power by the rectifier 38 and supplied to the charging unit of the vehicle V, and the power battery BATT is charged by the charging unit.

  Next, detailed configurations of the power feeding unit 22 and the power receiving unit 32 described in the above outline will be described with reference to FIG. As described above, the power feeding and power receiving units 22 and 32 include the power feeding and power receiving coils 23 and 33, the power feeding and power receiving capacitor bodies 24 and 34, the braided sheets 25 and 35, and the power feeding and power receiving cases 26 and 36, respectively. I have.

  As shown in FIG. 3, each of the power feeding and receiving coils 23 and 33 has a rectangular flat plate core 3A made of, for example, ferrite, and a coil wire 3B wound around the core 3A in a coil shape. The power feeding and receiving capacitor bodies 24 and 34 include a substrate 4A on a rectangular flat plate having a wiring pattern formed on the surface of a glass epoxy substrate, and a plurality of capacitors (not shown) mounted on the substrate 4A. ing.

  The braided sheet 25 on the power feeding side is provided in a rectangular sheet shape so as to cover the entire surface of the power feeding coil 23 on the side opposite to the power receiving coil 33 (mating coil). The power receiving side braided sheet 35 is provided in a rectangular sheet shape so as to cover the entire surface of the power receiving coil 33 on the side opposite to the power feeding coil 23 (mating coil). That is, the braided sheets 25 and 35 are provided in a larger area than the core 3A.

  The braided sheets 25 and 35 are composed of a plurality of sheet main bodies 5A, a copper wire 5B as a conductive member connected to the periphery of the sheet main body 5A, and a pair of copper plates 5C as conductive members. The sheet body 5A is formed in a sheet shape by weaving a plurality of litz wires. In the present embodiment, the sheet body 5A is formed in a belt shape. Each of the litz wires is formed by twisting a plurality of copper wires (conductive wires), each of which is insulated with, for example, enamel. For this reason, the plurality of litz wires constituting the sheet body 5A are insulated from each other. Therefore, the plurality of litz wires are electrically connected to each other by the copper wire 5B provided at the edge of the sheet main body 5A.

  Specifically, the end portion of the litz wire that becomes the peripheral portion of the sheet body 5A is electrically connected to the copper wire 5B with solder or the like after the insulation coating is removed. In the present embodiment, the entire periphery of the sheet body 5A is bordered by the copper wire 5B. One braided sheet 25, 35 is formed by arranging a plurality of sheet bodies 5A bordered by the copper wire 5B in the band width direction and joining them together. The copper plate 5C is for connecting a plurality of sheet main bodies 5A, and is connected to a pair of edges (copper wire 5B) along the band width direction. By connecting the copper plate 5C to the ground, the litz wires constituting the braided sheets 25 and 35 can be connected to the ground.

  By covering the power receiving and receiving coils 23 and 33 with the conductive braided sheets 25 and 35 grounded in this way, the braided sheets 25 and 35 function as a shield part, and electromagnetic waves generated from the power supplying and receiving coils 23 and 33 are obtained. Noise leakage can be prevented.

  As shown in FIG. 2, the power feeding and power receiving cases 26 and 36 are configured to be divided into a main body 6A provided with an opening and a lid 6B covering the opening of the main body 6A. The main body 6A and the lid 6B are made of a material capable of passing magnetism from a power feeding device such as fiber reinforced plastic (FRP).

  The power feeding and power receiving cases 26 and 36 are combined with the main body portion 6A and the lid portion 6B and fixed by fixing means such as screws (not shown), so that the power feeding, power receiving coils 23 and 33 and the power feeding, power receiving capacitor body 24, An accommodation space for accommodating 34 and the like is formed. The power supply case 26 is disposed on the ground such that the lid 6B is on the ground G side and the main body 6A is on the vehicle V side. The power receiving case 36 is attached to the lower surface of the vehicle V so that the lid portion 6B is on the lower surface side of the vehicle V and the main body portion 6A is on the ground G side. The braided sheets 25 and 35 are attached to the lid portion 6B, for example.

  According to the embodiment described above, the litz wire is formed by twisting a plurality of thin copper wires with insulation coating. For this reason, since the braided sheets 25 and 35 are formed by braiding a plurality of copper wires having a small cross-sectional area, the resistance can be reduced even at high frequencies compared to a conventional copper plate shield having a large cross-sectional area.

  This will be described with reference to FIG. FIG. 4 is a graph showing a rate of increase in resistance with respect to the frequency of the conventional copper plate shield and the braided sheet of the present embodiment. In FIG. 4, the upper areas of the copper shield and the braided sheets 25, 35 are the same. In FIG. 4, the cross-sectional area of the copper plate shield is the same as the sum of the cross-sectional areas of the litz wires constituting the braided sheets 25 and 35. As shown in the figure, in the conventional copper plate shield, the resistance value of the copper plate shield increases as the frequency of the current flowing therethrough increases.

  On the other hand, the braided sheets 25 and 35 also increase in resistance value of the braided sheets 25 and 35 as the current frequency increases, but the amount of increase is smaller than that of the copper plate shield. Even if the braided sheets 25 and 35 are at a high frequency, the resistance can be lowered, and as shown in FIG. 5, even if an eddy current flows through the braided sheets 25 and 35, the temperature rise can be suppressed compared to the copper plate shield. .

  Moreover, according to embodiment mentioned above, since the several litz wire is mutually electrically connected by the copper wire 5B and the copper plate 5C which were provided in the edge of the sheet | seat main body 5A, 1 of the copper wire 5B and the copper plate 5C A plurality of litz wires can be easily set to the ground potential simply by connecting the places to the ground.

  In addition, according to embodiment mentioned above, although the braided sheets 25 and 35 were provided from the several sheet | seat main body 5A, it is not restricted to this. For example, as shown in FIG. 7, the braided sheets 25 and 35 may be provided from one sheet body 5A, and a copper plate 5C may be provided on the entire periphery of the sheet body 5A.

  Moreover, according to embodiment mentioned above, although the braided sheets 25 and 35 comprised the some strip | belt-shaped sheet | seat main bodies 5A arranged in the strip | belt width direction, it is not restricted to this. For example, as shown in FIG. 8, it is also conceivable that a belt-shaped sheet body 5D is further joined to a pair of copper plates 5C. One of the pair of edge portions along the longitudinal direction of the copper plate 5C is connected to the edge portion along the band width direction of the sheet main body 5A described above, and the other is connected to the band length direction of the sheet main body 5D described above. The edges along the line are connected. Moreover, the copper plate 5E is connected to the edge part along one band width direction among a pair of sheet | seat main bodies 5D, and this is connected to a ground.

  In addition, according to embodiment mentioned above, although the braided sheets 25 and 35 were attached to the cover part 6B, it is not restricted to this. For example, the braided sheets 25 and 35 may be attached to the opening of the main body 6A instead of the lid 6B.

  According to the above-described embodiment, the feeding and receiving coils 23 and 33 are formed by winding the coil wire 3B in a spiral shape, but the present invention is not limited to this. The power feeding and power receiving coils 23 and 33 may be those used for non-contact power feeding. For example, the coil wire 3B may be formed in a spiral shape on the substrate.

  According to the embodiment described above, the sheet main body 5A is provided by weaving a plurality of litz wires, but the present invention is not limited to this. For example, the sheet body 5A may be provided by weaving one litz wire.

  Further, according to the above-described embodiment, the braided sheets 25 and 35 are provided in the power feeding and power receiving units 22 and 32. However, the present invention is not limited to this. Only one of the power feeding and power receiving units 22 and 32 may be used.

  Further, the above-described embodiments are merely representative forms of the present invention, and the present invention is not limited to the embodiments. That is, various modifications can be made without departing from the scope of the present invention.

1 Power Supply System 5A Sheet Main Body 5B Copper Wire (Conductive Member)
5C copper plate (conductive member)
5D sheet body 5E copper plate (conductive member)
20 Power supply device (power supply unit)
22 Power supply unit (coil unit)
23 Feed coil (coil)
25 Braided sheet (shield part)
30 Power receiving device (power receiving unit)
32 Power receiving unit (coil unit)
33 Power receiving coil (coil)
35 Braided sheet (shield part)

Claims (3)

A coil unit comprising: a coil that supplies power to or receives power from a counterpart coil in a non-contact manner; and a conductive shield portion that covers a side opposite to the counterpart coil of the coil,
The said shield part is comprised from the braided sheet | seat provided in the sheet form knitting the litz wire formed by twisting the several conducting wire by which each one was insulation-coated. The coil unit characterized by the above-mentioned. The braided sheet has a sheet body provided by braiding a plurality of litz wires, and a conductive member provided at an edge of the plurality of sheet bodies and electrically connecting the plurality of litz wires to each other. The coil unit according to claim 1, wherein: A power supply system having a power supply unit provided on the ground and a power reception unit provided on a vehicle, wherein the power reception unit receives power transmitted from the power supply unit in a contactless manner;
At least one of the power feeding unit or the power receiving unit includes the coil unit according to claim 1 or 2.

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