WO2014076953A1 - Core to be used in coil of non-contact power transmission apparatus - Google Patents

Abstract

This core to be used in a coil of a non-contact power transmission apparatus is provided with: a core winding center portion (32), which has an electric wire (31) wound thereon, and which extends in the first direction; a discontinuous portion (34); and a core protruding portion (35) that extends in the second direction perpendicular to the first direction. The core winding center portion (32), the discontinuous portion (34), and the core protruding portion (35) are disposed in this order in the first direction.

Description

Core used for coils of devices that transmit power without contact

The present invention relates to a power feeding device and a power receiving device of a non-contact power transmission system used for charging an electric propulsion vehicle such as an electric vehicle or a plug-in hybrid vehicle.

FIG. 9 is a schematic diagram (cross-sectional view) showing a configuration of a coil of a conventional non-contact power transmission system described in Patent Document 1. This non-contact power transmission system includes a power transmission coil 112 and a power reception coil 118, and includes an electric wire 131 and a core 132 using a magnetic material such as ferrite. And the uppermost part of the surface of the core 132 on the side facing the mating coil has a height equal to or higher than the outer circumference of the electric wire 131 with respect to the mating coil.

In this manner, by extending the core 132 above the wire 131 (on the other coil side), the core 132 is transmitted through the air in the magnetic path without reducing the distance between the power transmission coil 112 and the power reception coil 118 of the non-contact power feeding device. The distance can be shortened. Thereby, the coupling coefficient between coils becomes high, and it becomes possible to raise feed efficiency and maximum feed power. Therefore, it is possible to provide a non-contact power supply core that has high power supply efficiency, high mechanical strength, easy manufacturing, and low cost.

JP 2012-151111 A

However, as described above, when the configuration in which the core 132 is extended upward is used, a large amount of magnetic flux is concentrated in the winding axis direction of the coil. FIG. 10 is an explanatory diagram of the magnetic flux vector of the coil when the core 132 is extended upward. A magnetic flux 140 in the core 132 generated by the electric wire 131 goes upward through the core 132. In the air, the same magnetic flux density as that in the magnetic body cannot be maintained, so that the magnetic flux is diffused in the direction in which the magnetic flux density decreases (for example, the direction perpendicular to the core surface) in the vicinity of the end of the core 132.

When the core is integrally formed from the portion where the electric wire 131 is wound to the end, most of the magnetic flux 140 in the core 132 generated by the electric wire 131 is transmitted to the vicinity of the end of the core 132. Therefore, the leakage magnetic flux 141 in the winding axis direction of the coil increases due to diffusion from the vicinity of the end of the core 132. Further, the magnetic flux that diffuses near the end of the core 132 also becomes stronger. For this reason, when the coil winding axis direction is set to be horizontal, the magnetic field leakage to the periphery increases.

The present invention relates to a core used for a coil of a power feeding device or a power receiving device capable of reducing leakage magnetic flux to the periphery even in an installation configuration in which the winding axis direction of the coil is horizontal in a non-contact power transmission system. The purpose is to provide.

In one aspect of the present invention, a core used for a coil of a device that transmits power in a non-contact manner, the core being wound with an electric wire and extending in a first direction, and a discontinuity And a core protruding portion extending in a second direction perpendicular to the first direction, the core winding core portion, the discontinuous portion, and the core protruding portion in the first direction. Are arranged in order.

According to the present invention, by providing a discontinuous portion in the core protruding portion, the magnetic flux transmitted from the core winding core portion is once diffused, and a part of the magnetic flux is received by the next core protruding portion and guided to the power transmission side. The leakage magnetic field in the coil winding axis direction (first direction) can be reduced.

Block diagram of a non-contact power transmission system in the first embodiment External view of contactless power transmission system according to Embodiment 1 Vertical sectional view of the coil of the non-contact power transmission system in the first embodiment Magnetic flux vector explanatory diagram of the coil in the first embodiment Vertical sectional view of the coil in the second embodiment Horizontal plan view of coil in embodiment 2 Horizontal plan view of coil in embodiment 3 Vertical sectional view of the coil in the fourth embodiment Schematic diagram of a coil of a conventional non-contact power transmission system Illustration of magnetic flux vector of conventional coil

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the present embodiment.

(Embodiment 1)
FIG. 1 is a block diagram of a contactless power transmission system according to Embodiment 1 of the present invention. FIG. 2 is an external view of the non-contact power transmission system in a state where the vehicle is stopped in the parking space.

1 and 2, the non-contact power transmission system includes, for example, a power feeding device 2 installed in a parking space and a power receiving device 4 mounted on, for example, an electric propulsion vehicle.

The power supply device 2 includes a power supply box 8 connected to the commercial power supply 6, an inverter unit 10, a ground side coil unit 12, and a control unit (for example, a microcomputer) 16 on the power supply device side that constitutes the power control device 17. I have. On the other hand, the power receiving device 4 includes a vehicle side coil unit 18, a rectifying unit 20, a battery 22 as a load, and a control unit (for example, a microcomputer) 24 on the power receiving device side.

In the power supply device 2, the commercial power source 6 is a 200 V commercial power source that is a low-frequency AC power source, and is connected to the input end of the power source box 8. The output end of the power supply box 8 is connected to the input end of the inverter unit 10, and the output end of the inverter unit 10 is connected to the ground side coil unit 12. On the other hand, in the power receiving device 4, the output end of the vehicle side coil unit 18 is connected to the input end of the rectifying unit 20, and the output end of the rectifying unit 20 is connected to the battery 22.

Further, the ground side coil unit 12 is laid on the ground, and the power supply box 8 is erected at a position separated from the ground side coil unit 12 by a predetermined distance, for example. On the other hand, the vehicle side coil unit 18 is attached to, for example, a vehicle body bottom (for example, a chassis).

The control unit 16 on the power feeding device side communicates with the control unit 24 on the power receiving device side, and the control unit 24 on the power receiving device side determines a power command value according to the detected remaining voltage of the battery 22 and determines the determined power. The command value is transmitted to the control unit 16 on the power feeding apparatus side. The control unit 16 on the power supply device side compares the power supply power detected by the ground side coil unit 12 with the received power command value, and drives the inverter unit 10 to obtain the power command value.

When power is supplied from the power feeding device 2 to the power receiving device 4, as shown in FIG. 2, the vehicle side coil unit 18 is disposed to face the ground side coil unit 12 by appropriately moving the vehicle. And the control part 16 by the side of an electric power feeder controls drive of the inverter part 10, and forms a high frequency electromagnetic field between the ground side coil unit 12 and the vehicle side coil unit 18. FIG. The power receiving device 4 takes out electric power from a high frequency electromagnetic field and charges the battery 22 with the taken out electric power.

FIG. 3 is a vertical cross-sectional view of the coil of the non-contact power transmission system according to Embodiment 1 of the present invention. FIG. 3 shows the coil 30 of the ground side coil unit 12.

The coil 30 includes an electric wire 31 and a core using a magnetic material such as ferrite. Thereafter, the portion of the core covered with the electric wire 31 extends in the horizontal direction continuously to the core winding core portion 32 and the core winding core portion 32, and the portion not covered with the electric wire 31 is unwound. A portion extending from the portion 33 and the non-winding portion 33 across the discontinuous portion 34 and extending in the vertical direction is referred to as a core protruding portion 35.

In the present specification, the discontinuous portion 34 refers to the core winding core portion 32 extending in the horizontal direction (first direction) and the vertical direction (second direction perpendicular to the first direction). It indicates a discontinuous portion between the core protrusions 35 extending in the direction of, for example, a portion where the core winding core portion 32 does not continuously extend, such as a space, a shape change, and a material change. In addition, the core winding core part 32 may have the non-winding part 33 in which the electric wire is not wound in the vicinity of the discontinuous part 34 side. In the following embodiment, a case where the non-winding portion 33 is provided will be described as an example.

That is, the core in the present invention is wound around the electric wire and extends in the second direction perpendicular to the first direction, the core winding core part 32 extending in the first direction, the discontinuous part 34, and the core. The core winding part 32, the discontinuous part 34, and the core protrusion part 35 are arranged in this order in the first direction.

The output from the inverter unit 10 is transmitted to the electric wire 31, and magnetic flux is generated. The generated magnetic flux is transmitted from the core winding core portion 32 to the non-winding portion 33, and further transmitted to the core protruding portion 35 through the discontinuous portion 34. Since the core protrusion 35 extends upward (vehicle-side coil unit 18 side), it forms a magnetic path mainly toward the upper side. By this magnetic path, a high-frequency electromagnetic field for power transmission is formed between the ground side coil unit 12 and the vehicle side coil unit 18 disposed above the ground side coil unit 12.

FIG. 4 is an explanatory diagram of the magnetic flux vector of the coil according to the first embodiment of the present invention. The magnetic flux 40 in the core generated by the electric wire 31 goes upward through the non-winding portion 33, the discontinuous portion 34, and the core protruding portion 35. In the vicinity of the terminal end of the non-winding portion 33 before the discontinuous portion 34, magnetic flux is diffused, and the magnetic flux is directed in the coil winding axis direction (horizontal direction) and the vertical direction (vertical direction). The downward magnetic flux was canceled by a magnetic-shielding member (not shown) such as an aluminum plate and weakened, and the upward magnetic flux contributed to the formation of a high-frequency electromagnetic field and directed to the remaining coil winding axis direction. The magnetic flux enters the core protrusion 35. The magnetic flux 40 in the core protruding portion 35 is directed upward and diffusion of the magnetic flux occurs in the vicinity of the terminal end. However, since it is a part of the magnetic flux once diffused before the discontinuous portion 34, the coil winding axis direction (horizontal direction) ) Is smaller than the leakage flux 141 of FIG.

The non-winding portion 33 and the core winding core portion 32 are integrally formed, and the upper surface 37 of the non-winding portion 33 is substantially the same height as the upper surface 36 of the core winding core portion 32, and thus is generated in the electric wire 31. The magnetic flux 40 is transmitted to the vicinity of the end of the non-winding portion 33 without any extreme magnetic flux diffusion. Further, since the upper surface 38 of the core protruding portion 35 is higher than the upper surface 37 of the non-winding portion 33, a large amount of magnetic flux is collected to form an upward magnetic path.

In the first embodiment of the present invention, a physical space (discontinuous portion 34) is provided between the non-winding portion 33 and the core protruding portion 35 in order to diffuse a part of the magnetic flux in the vertical direction in the middle. However, in order to reduce the leakage magnetic flux 41, it is sufficient that a gap is physically available.

Moreover, the core winding core part 32, the non-winding part 33, and the core protrusion part 35 are parts related to the core. Parts are not applicable.

(Embodiment 2)
FIG. 5 shows a vertical cross-sectional view of the coil according to the second embodiment of the present invention. In the first embodiment, the discontinuous portion 34 is a space. However, in the present embodiment, a core having a smaller core cross-sectional area in the coil winding axis direction (first direction) than the non-winding portion 33 is used. A discontinuous portion 34 is provided. In FIG. 5, the upper side of the discontinuous portion 34 is recessed as compared with the non-winding portion 33. In the case of this configuration, the core cross-sectional area in the first direction (horizontal direction) in which a large amount of magnetic flux is transmitted becomes narrower from the non-winding portion 33 to the discontinuous portion 34, thereby causing the diffusion of magnetic flux and providing a space. The same effect as the case can be obtained.

In FIG. 5, since the upper side is made discontinuous by making it concave, a large amount of diffusion on the upper side can be generated. Therefore, it is possible to reduce the downward magnetic flux diffusion that does not contribute to the formation of a high-frequency electromagnetic field.

FIG. 6 shows a horizontal sectional view of the coil according to the second embodiment of the present invention. As shown in FIG. 6, the left and right sides of the discontinuous portion 34 are recessed compared to the non-winding portion 33. Similarly in the case of this configuration, the leakage magnetic flux 41 can be reduced. In FIG. 6, since the left and right sides are recessed to make them discontinuous, it is possible to reduce the left and right magnetic flux diffusion.

In the present embodiment, the description has been made using the shape in which the upper side or the left and right sides are recessed. However, the leakage magnetic flux 41 is similarly reduced when only the lower side, both the upper and lower sides, only the left and right sides, or a combination thereof. It becomes possible to do.

(Embodiment 3)
FIG. 7 shows a horizontal sectional view of the coil according to the third embodiment of the present invention. In the second embodiment, the outer periphery of the discontinuous portion 34 is recessed. However, in the present embodiment, a core having a space inside the discontinuous portion 34 is used as the discontinuous portion 34.

Also in this configuration, since the diffusion of the magnetic flux occurs when the core cross-sectional area in the direction (horizontal direction) in which a large amount of magnetic flux is transmitted becomes narrower from the non-winding portion 33 to the discontinuous portion 34, the same effect can be obtained. I can do it.

In addition, in FIG. 7, although it demonstrated using the shape provided with the space penetrated in the perpendicular direction in the center part of the discontinuous part 34, when not penetrating (hollow), the space is biased up and down, right and left In this case, the same effect can be obtained.

(Embodiment 4)
FIG. 8 shows a vertical cross-sectional view of the coil according to the fourth embodiment of the present invention. In the first embodiment, the discontinuous portion 34 is a space, but in this embodiment, a core made of a magnetic material different from the non-winding portion 33 and the core protruding portion 35 is used as the discontinuous portion 34.

Since the magnetic flux is diffused by sandwiching a material having a higher magnetic resistance than the non-winding portion 33 as the discontinuous portion 34, the same effect as when a space is provided can be obtained.

In the case of FIG. 8, the amount of magnetic flux transmitted to the core protrusion 35 can be adjusted by adjusting the specifications such as the magnetic permeability of the magnetic material of the discontinuous portion 34.

As mentioned above, in this Embodiment, although the structure which provided the discontinuous part 34 in the ground side coil unit 12 of the electric power feeder 2 was demonstrated as an example, this invention is not limited only about such a case, For example, the discontinuous portion 34 may be provided in the vehicle side coil unit 18 of the power receiving device 4. Moreover, it is good also as a structure which provides the discontinuous part 34 in both the ground side coil unit 12 of the electric power feeder 2 and the vehicle side coil unit 18 of the power receiving apparatus 4. FIG.

In addition, in FIG. 3, although the discontinuous part 34 is provided in the left-right both directions of the coil 30, it is good also as a structure which provides the discontinuous part 34 only in either one.

Similarly, in FIGS. 4 to 8, the description is made by using only the left side of the coil 30, but either a configuration in which the discontinuous portion 34 is provided only on one of them or a configuration in which the discontinuous portion 34 is provided on both the left and right sides. Good.

Furthermore, although the present embodiment has been described using a square core, the effect of the present invention does not depend on the core shape. Therefore, it may be a core having another shape such as a cylindrical shape.

Further, in the present embodiment, the ground side is described as the power feeding device and the vehicle side is the power receiving device. However, the configuration in which the ground side is the power receiving device and the vehicle side is the power feeding device, and both the ground side and the vehicle side are It may be configured to receive power and to supply power.

It should be noted that any of the various embodiments described above may be combined as appropriate to achieve the respective effects.

As described above, the core used for the coil of the non-contact power transmission device according to the present invention has a configuration in which a discontinuous portion is provided in the middle of the protruding portion of the core, thereby reducing leakage magnetic flux to the periphery. For example, it is useful for a power receiving device and a power feeding device for an electric propulsion vehicle in which a person or an object may approach carelessly or accidentally.

DESCRIPTION OF SYMBOLS 2 Electric power feeder 4 Power receiving device 6 Commercial power supply 8 Power supply box 10 Inverter part 12 Ground side coil unit 16 Control part 17 Power control device 18 Vehicle side coil unit 20 Rectification part 22 Battery 24 Control part 30 Coil 31, 131 Electric wire 32 Core winding core Part 33 Non-winding part 34 Discontinuous part 35 Core protrusion part 36 Upper surface of core winding core part 37 Upper surface of non-winding part 38 Upper surface of core protrusion part 40, 140 Magnetic flux 41, 141 Leakage magnetic flux 112 Power transmission coil 118 Power receiving coil 132 core

Claims (5)

1. A core used for a coil of a device that transmits power without contact,
   The core is
   A core winding core portion wound with an electric wire and extending in a first direction;
   Discontinuities,
   A core protrusion extending in a second direction perpendicular to the first direction,
   The core, wherein the core winding core part, the discontinuous part, and the core protruding part are sequentially arranged in the first direction.
2. The core according to claim 1, wherein the discontinuous portion is a space between the core winding core portion and the core protruding portion.
3. The core according to claim 1, wherein a cross-sectional area of the discontinuous portion in the first direction is smaller than a cross-sectional area of the core winding core portion in the first direction.
4. The core according to claim 1, wherein the discontinuous portion is a magnetic material different from the core winding core portion and the core protruding portion.
5. The core according to claim 1, wherein the core winding core portion has a non-winding portion around which the electric wire is not wound on the discontinuous portion side.

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