JP6454941B2 - Non-contact power supply device and non-contact power supply system - Google Patents

Description

  The present invention relates to a non-contact power supply apparatus and a non-contact power supply system, and more particularly to a non-contact power supply apparatus and a non-contact power supply system that use a coil to perform non-contact power supply to the outside.

  As a conventional example, a non-contact charging device (non-contact power feeding system) described in Patent Document 1 is illustrated. The non-contact charging device (non-contact power feeding system) described in Patent Literature 1 includes a power receiving device (non-contact power receiving device), a power feeding device (non-contact power feeding device), and a storage battery. The power feeding device and the power receiving device are non-contact charging devices using electromagnetic force. The power supply apparatus includes a power supply unit having a shield, a power supply coil, a power supply inverter, a power supply circuit, and the like. The shield is a rectangular parallelepiped housing that houses the feeding coil, and is made of a material having an electromagnetic wave shielding effect. The power receiving device and the storage battery are provided in a vehicle (electric vehicle). The power receiving device includes a power receiving coil, a rectifier, and the like. The vehicle travels using a battery as a power source. The power feeding device is provided, for example, in a parking space. The power feeding device feeds power to a power receiving device provided in the vehicle while the vehicle is parked. The power receiving device supplies power supplied from the power supply device to the storage battery.

JP 2014-193031 A

  In the power supply apparatus (non-contact power supply apparatus) described in Patent Document 1, a planar coil such as a spiral coil may be used as a power supply coil. In this case, a space surrounded by the spiral coil exists in the shield. Therefore, in order to effectively use the space, it is preferable to arrange a power supply unit that supplies power to the feeding coil in the space. However, since the magnetic flux generated around the power supply coil passes through the space, various problems may occur in the power supply unit disposed in the space. For example, when a magnetic flux is linked to a conductor (copper foil) of a printed wiring board that constitutes a power supply unit, heat may be generated due to eddy current loss of the conductor.

  This invention is made | formed in view of the said reason, and it aims at reducing the influence of the magnetic flux to the space enclosed by the electric power feeding coil.

  The non-contact power supply device of the present invention includes a base made of a magnetic material, a power supply coil, and a power supply unit that causes a current to flow through the power supply coil to generate a magnetic flux in the power supply coil, and the base is formed in a plate shape. The power supply coil is disposed on the first surface of the base with a central axis in the same direction as the thickness direction of the base, and the position of the base is surrounded by the power supply coil including the central axis. An inner wall that protrudes from the first surface along the inner periphery of the power feeding coil is provided, and the storage space surrounded by the inner wall has the same area as the first surface and the storage space on the same surface as the tip of the inner wall. The inner wall is formed to be larger than the area.

  The contactless power feeding system of the present invention includes the contactless power feeding device and a contactless power receiving device that receives power supplied from the contacted power feeding device.

  The non-contact power feeding device of the present invention has an effect that the influence of the magnetic flux on the space surrounded by the power feeding coil can be reduced.

It is the schematic which shows the usage example of embodiment of the non-contact electric power feeding system which concerns on this invention. It is a disassembled perspective view which shows embodiment of the non-contact electric power feeder which concerns on this invention. FIG. 3A is a cross-sectional view showing an embodiment of the non-contact power supply apparatus, and FIG. 3B is a cross-sectional view showing a main part of the embodiment of the non-contact power supply apparatus. It is a circuit schematic diagram showing the composition of the embodiment of the non-contact electric supply system concerning the present invention. FIG. 5A is a plan view showing the main part of the power feeding device, FIG. 5B is a plan view showing the power receiving coil, and FIG. 5C is a plan view showing a case where the main part of the power feeding device and the power receiving coil overlap. It is. It is sectional drawing of the comparative example 1 of the non-contact electric power supply which concerns on this invention. It is sectional drawing of the comparative example 2 of a non-contact electric power feeder. It is a figure which shows a resonance characteristic in a non-contact electric power feeding system.

  Hereinafter, embodiments of a contactless power supply device and a contactless power supply system according to the present invention will be described in detail with reference to the drawings. In the present embodiment, a contactless power supply device and a contactless power supply system used for charging an electric vehicle are illustrated. However, the non-contact power feeding device and the non-contact power feeding system of the present embodiment can be used for applications other than charging an electric vehicle. In the following description, unless otherwise specified, the vertical, horizontal, and longitudinal directions are defined in FIG.

  As shown in FIG. 1, the non-contact power feeding system of the present embodiment includes a non-contact power feeding device 1 disposed on the ground and a non-contact power receiving device 2 mounted inside an electric vehicle.

  As shown in FIG. 2, the non-contact power feeding device 1 includes a housing 11, a power feeding coil L <b> 1, an inner wall 12, a storage space 13, a power supply unit 14, and a cover 15.

  The housing 11 includes a base 111 and an outer wall 112. The base 111 is formed of a soft magnetic material (for example, soft ferrite) into a rectangular plate shape whose longitudinal direction is the left-right direction. The outer wall 112 protrudes upward from the periphery of the base 111 with a soft magnetic material. The outer wall 112 is formed to be slightly higher than the height at which the position shift of the power feeding coil L1 can be prevented, for example, the height in the vertical direction of the power feeding coil. The housing 11 is formed by a base 111 and an outer wall 112 in a box shape whose upper surface is open. In addition, since the magnetic flux easily passes through the soft magnetic material (the magnetic permeability is high), it is difficult for the magnetic flux to leak to the outside of the housing 11, and the influence of the magnetic flux can be reduced outside the housing 11.

  As shown in FIG. 3B, the power supply coil L1 is preferably composed of a conducting wire L11 (flat conductor) having a rectangular cross section and an insulating coating L12 covering the conducting wire L11. As shown in FIG. 2, the power supply coil L1 is formed by winding a conductive wire L11 covered with an insulating film L12 on a plane in a spiral shape. Moreover, it is preferable that the feeding coil L1 is wound in the same direction as the central axis in the longitudinal direction of the cross section of the conducting wire L11. The feeding coil L1 is a square type planar coil configured as described above, a so-called spiral coil. The feeding coil L1 is disposed inside the housing 11 so that the central axis faces the up-down direction (base thickness direction). The feeding coil L1 is electrically connected to the power supply unit 14, and generates a magnetic flux when a current supplied from the power supply unit 14 flows (see FIG. 4).

  In addition to the square type, the spiral coil includes a circular type and an oval type, and a circular type and an oval type may be used. Moreover, the shape of the cross section of the conducting wire L11 is not limited to a rectangle.

  The inner wall 12 is formed of a soft magnetic material at a position surrounded by the feeding coil L1 so as to be along the inner peripheral edge of the feeding coil L1. The inner wall 12 is composed of two pairs of walls protruding from the base 111. The inner wall 12 includes a pair of first walls 121 facing in the left-right direction and a pair of second walls 122 facing in the front-rear direction. A pair of 1st wall 121 inclines in the direction which mutually approaches toward upper direction. Similar to the first wall 121, the pair of second walls 122 are inclined in a direction approaching each other upward. That is, the inner wall 12 has a storage space 13 inside, and is formed in a quadrangular frustum shape whose upper surface is open.

  In the storage space 13, as shown in FIG. 3A, the power supply unit 14 is attached to the upper surface (first surface) of the base 111.

  The power supply unit 14 is a circuit that converts AC power of the commercial AC power supply 100 into desired high-frequency power and supplies it to the feeding coil L1, and as shown in FIG. 4, a rectifying / smoothing circuit 141, an inverter circuit 142, and a control A circuit 143 and a capacitor C1 are provided. The rectifying / smoothing circuit 141 rectifies and smoothes the AC voltage supplied from the commercial AC power supply 100. The rectifying / smoothing circuit 141 is preferably composed of a diode bridge composed of four diodes and a power factor correction circuit. The AC voltage is rectified by a diode bridge and smoothed by a power factor correction circuit. The rectifying / smoothing circuit 141 may use a boost chopper circuit, a smoothing capacitor, or the like instead of the power factor correction circuit. The inverter circuit 142 is, for example, a full-bridge type inverter circuit, and an AC having a frequency (high frequency) higher than the frequency of the AC voltage supplied from the commercial AC power supply 100 is a voltage rectified and smoothed by the rectifying and smoothing circuit 141. Convert to voltage. The control circuit 143 is configured to control the rectifying / smoothing circuit 141 and the inverter circuit 142. The control circuit 143 is preferably composed of, for example, a microcontroller. The capacitor C1 is electrically connected in series with the feeding coil L1. The high-frequency AC voltage output from the inverter circuit 142 is boosted by the resonance action of the series resonance circuit of the capacitor C1 and the feeding coil L1.

  The inner wall 12 is formed higher than the height at which the power supply unit 14 is hardly affected by magnetic flux, for example, the height of circuit components mounted on the power supply unit 14 (see FIG. 3A).

  As shown in FIG. 2, the cover 15 is formed in a rectangular plate shape with the left-right direction as the longitudinal direction so as to close the opening of the housing 11 by FRP (Fiber Reinforced Plastics) or the like. The cover 15 may be formed in a box shape that covers the housing 11.

  As shown in FIG. 1, the non-contact power receiving device 2 is mounted on the body of the electric vehicle 20. As illustrated in FIG. 4, the non-contact power receiving device 2 includes a power receiving coil L2, a capacitor C2, and a rectifier circuit 21.

  The power receiving coil L2 is a spiral coil. The power receiving coil L2 is disposed on a pedestal formed of a soft magnetic material. The power receiving coil L2 is disposed on the vehicle body of the electric vehicle 20 so that the center axis overlaps the center axis of the power feeding coil L1 when the electric vehicle 20 stops at a predetermined stop position. The power receiving coil L2 is provided at a position below the vehicle body of the electric vehicle 20 and between the front wheel and the rear wheel (see FIG. 1). An alternating current flows through the power receiving coil L2 due to electromagnetic induction generated from the magnetic flux generated by the power feeding coil L1. That is, the receiving coil L2 receives the magnetic flux generated by the feeding coil L1 and transmits AC power.

  The capacitor C2 is electrically connected in series with the power receiving coil L2, as shown in FIG. The capacitor C2 forms a resonance circuit together with the power receiving coil L2.

  The rectifier circuit 21 is electrically connected to the power receiving coil L2 via the capacitor C2. The rectifier circuit 21 is configured by a diode bridge, for example, and rectifies an alternating current generated in the power receiving coil L2.

  The vehicle body of the electric vehicle 20 further includes a charging circuit 22 and a battery 23. The charging circuit 22 is electrically connected to the rectifier circuit 21 and appropriately converts the power rectified by the rectifier circuit 21 to charge the battery 23. The battery 23 is constituted by, for example, a nickel metal hydride battery, a lithium ion battery, an electric double layer capacitor, or the like. The battery 23 is used as a power source for an electric motor (motor) included in the vehicle body of the electric vehicle 20. In addition, the battery 23 may be used as a power source for an electronic device included in the body of the electric vehicle 20.

  In FIG. 3A, an arc-like broken line arrow represents the magnetic flux generated by the feeding coil L1.

  Since the magnetic flux generated by the power feeding coil L1 passes through the inner wall 12, the non-contact power feeding device 1 of the present embodiment can reduce the magnetic flux leaking to the storage space 13. By providing the inner wall 12, the contactless power supply device 1 of the present embodiment can reduce the influence of magnetic flux generated from the power supply coil L <b> 1 in the power supply unit 14 stored in the storage space 13.

  By the way, in the non-contact electric power feeding system of this embodiment, as shown to FIG. 5C, it is preferable that the electric vehicle 20 stops in the position where the central axis of the feeding coil L1 and the central axis of the receiving coil L2 overlap in an up-down direction. However, the electric vehicle 20 does not necessarily stop at a position where the central axis of the feeding coil L1 and the central axis of the power receiving coil L2 overlap in the vertical direction. When the central axis of the feeding coil L1 and the central axis of the power receiving coil L2 are relatively different from each other in the vertical direction, the feeding efficiency is lowered. Since efficient power feeding is performed from the feeding coil L1 to the receiving coil L2, the area of the feeding coil L1 is as shown in FIGS. 5A, 5B, and 5C when viewed from the up and down direction. It is preferable to use a spiral coil larger than the area.

  The base 111 is not limited to a rectangular plate shape. The inner wall 12 does not have to be formed in a quadrangular frustum shape, and may be formed in a truncated cone shape or the like. The first wall 121 and the second wall 122 constituting the inner wall 12 may not be formed integrally. The configuration of the power supply unit 14 is not limited to the present embodiment. Further, only a part of the configuration of the power supply unit 14 may be disposed in the storage space 13.

  Comparative Example 1 and Comparative Example 2 of the present embodiment will be described with reference to FIGS. 6 and 7 respectively.

  The non-contact electric power feeder 4 of the comparative example 1 is demonstrated with reference to FIG. In FIG. 6, the arc-shaped broken line arrow represents the magnetic flux generated by the feeding coil L1.

  The non-contact power feeding device 4 of the comparative example 1 includes a box-shaped casing 41 composed of a base 411 and an outer wall 412 using a soft magnetic material, like the non-contact power feeding device 1 of the present embodiment. Similarly to the non-contact power feeding device 1 of the present embodiment, the base 411 and the outer wall 412 concentrate the magnetic flux generated from the power feeding coil L1, so that the non-contact power feeding device 4 of Comparative Example 1 has a magnetic flux outside the housing 41. Can be reduced. However, the non-contact power feeding device 4 of Comparative Example 1 is not provided with an inner wall as in the conventional example. As shown in FIG. 6, when the inner wall is not provided, the magnetic flux generated from the feeding coil L1 passes through the space 42 surrounded by the feeding coil L1. That is, compared with the storage space 13 of the contactless power supply device 1 of the present embodiment, the space 42 surrounded by the power supply coil L1 of the contactless power supply device 4 of Comparative Example 1 is more likely to be affected by magnetic flux. . Therefore, when the power supply unit 14 is arranged in the space 42 surrounded by the power supply coil L1, the magnetic flux is linked to the conductor (copper foil) of the printed wiring board constituting the power supply unit 14 and is caused by the eddy current loss of the conductor. There is a risk of generating heat.

  A non-contact power feeding device 5 of Comparative Example 2 will be described with reference to FIG. In FIG. 7, an arc-shaped broken line arrow represents a magnetic flux generated by the feeding coil L1.

  The non-contact power feeding device 5 of the comparative example 2 includes a box-shaped casing 51 that includes a base 511 and an outer wall 512 made of a soft magnetic material, like the non-contact power feeding device 1 of the present embodiment. Similarly to the non-contact power feeding apparatus 1 of the present embodiment, the base 511 and the outer wall 512 concentrate the magnetic flux generated from the power feeding coil L1, so that the influence of the magnetic flux can be reduced outside the housing 51. Further, the non-contact power feeding device 5 of the comparative example 2 includes an inner wall 52 in a place surrounded by the power feeding coil L1 inside the housing 51. The inner wall 52 includes a pair of walls facing in the front-rear direction projecting upward from the base 511 and a pair of walls facing in the left-right direction projecting upward. Unlike the inner wall 12 of the contactless power supply device 1 of the present embodiment, each of the pair of walls facing in the front-rear direction and the pair of walls facing in the left-right direction is formed perpendicular to the upper surface of the base 511. The inner wall 52 is provided with a storage space 53 in which the power supply unit 14 is disposed on the inner side, and is formed in a rectangular parallelepiped whose upper surface is open. Since the inner wall 52 concentrates the magnetic flux generated from the power supply coil L1, the power supply unit 14 disposed in the storage space 13 is not easily affected by the magnetic flux generated from the power supply coil L1. However, the distance between the upper end of the inner wall 52 and the upper end of the outer wall 512 is shorter than the distance between the upper end of the inner wall 12 and the upper end of the outer wall 112 of the non-contact power feeding device 1. That is, the range in which the magnetic flux affects the power receiving coil L2 is narrowed. In this case, when the center axis of the power receiving coil L2 is relatively displaced in the vertical direction from the center axis of the power feeding coil L1, the power receiving efficiency to the power receiving coil L2 is lowered.

  As shown in FIG. 3A, the non-contact power feeding device 1 of the present embodiment is provided with an inner wall 12 as compared with the non-contact power feeding device 4 of Comparative Example 1, thereby providing a power supply unit 14 disposed in the storage space 13. , The influence of the magnetic flux generated by the feeding coil L1 can be reduced. Furthermore, the non-contact power feeding device 1 of the present embodiment is formed such that each of the pair of first walls 121 and the pair of second walls 122 of the inner wall 12 approaches each other upward. Compared with the non-contact power feeding device 5 of the comparative example 2, the non-contact power feeding device 1 of the present embodiment has a wider range of influence of magnetic flux on the power receiving coil L2. Therefore, the non-contact power feeding device 1 of this embodiment can efficiently receive power by the magnetic flux generated by the power feeding coil L1 regardless of the relative displacement of the power receiving coil L2 of the non-contact power receiving device 2 with respect to the power feeding coil L1. Electric power is supplied to the coil L2.

  The feeding coil L1 and the receiving coil L2 in the above embodiment are preferably spiral coils. The spiral coil has an advantage that unnecessary radiation noise is less likely to occur compared to a solenoid type coil (in which a conductive wire is wound spirally around the core). Further, the use of the spiral coil has the advantage that the range of operating frequencies that can be used in the inverter circuit 142 is expanded as a result of reducing unnecessary radiation noise. Hereinafter, this point will be described in detail.

  That is, the resonance characteristics in the non-contact power feeding system of the present embodiment change according to the coupling coefficient between the power feeding coil L1 and the power receiving coil L2 as described above, and under certain conditions, the output characteristic is 2 as shown in FIG. It shows a so-called bimodal characteristic in which two maxima occur. In this resonance characteristic (bimodal characteristic), as shown in FIG. 8, two “mountains” in which the output is maximized at each of the first frequency fr1 and the third frequency fr3 are generated. Between these two “mountains”, a “valley” in which the output is minimized at the second frequency fr2 occurs. Here, the first frequency fr1, the second frequency fr2, and the third frequency fr3 are in a relationship of fr1 <fr2 <fr3. Hereinafter, on the basis of the second frequency fr2, a frequency region lower than the second frequency fr2 is referred to as a “low frequency region”, and a frequency region higher than the second frequency fr2 is referred to as a “high frequency region”.

  In such a resonance characteristic, each of a “mountain” in the low-frequency region (a mountain that becomes maximum at the first frequency fr1) and a “mountain” in the high-frequency region (a mountain that becomes maximum at the third frequency fr3). In addition, a region in which the inverter circuit 142 operates in the slow phase mode (hereinafter referred to as “slow phase region”) occurs. Therefore, the inverter circuit 142 can operate in the slow phase mode even when the operating frequency f1 is at any of the two “mountains”.

  Here, when the operation frequency f1 of the inverter circuit 142 is in the “mountain” of the low frequency region and the case of being in the “mountain” of the high frequency region, the case where the operation frequency f1 is in the “mountain” of the low frequency region is better. Unnecessary radiation noise is reduced. That is, in the “mountain” in the high frequency region, the current flowing through the feeding coil L1 and the current flowing through the receiving coil L2 are in phase. On the other hand, in the “mountain” in the low frequency region, the current flowing through the feeding coil L1 and the current flowing through the receiving coil L2 are in opposite phases. Therefore, in the “mountains” in the low frequency region, the unnecessary radiation noise generated in the power feeding coil L1 and the unnecessary radiation noise generated in the power receiving coil L2 cancel each other, and are unnecessary for the non-contact power feeding system as a whole. Radiation noise is reduced.

  Therefore, even when a solenoid type coil is employed, if the operating frequency f1 of the inverter circuit 142 is in the “mountain” slow phase region (fr1 to fr2) of the low frequency region, the inverter circuit 142 operates in the slow phase mode. In addition, unnecessary radiation noise is also reduced. However, since the slow phase region of the “mountain” in the low frequency region changes according to the coupling coefficient between the feeding coil L1 and the receiving coil L2, the operating frequency f1 of the inverter circuit 142 falls within such an uncertain slow phase region. Need to be controlled.

  On the other hand, in the case of a spiral coil, even if the operating frequency f1 of the inverter circuit 142 is in the “crest” slow phase region (higher frequency side than fr3) of the high frequency region, it is unnecessary radiation compared to the solenoid type coil. Noise is greatly reduced. That is, by using the spiral coil, the operating frequency f1 of the inverter circuit 142 is not limited to the “mountain” slow phase region of the low frequency region, and the range of the operating frequency f1 usable in the inverter circuit 142 is expanded. It will be. Although the slow phase region of the “mountain” in the high frequency region is an uncertain region, if the operating frequency f1 of the inverter circuit 142 is swept from a sufficiently high frequency to a low frequency side, the operating frequency f1 becomes “ Since it passes through the lagging region of the mountain, complicated control is unnecessary.

  Note that the slow phase mode is a mode in which the inverter circuit 142 operates in a state where the output current of the inverter circuit 142 is delayed from the phase of the output voltage of the inverter circuit 142.

  The contactless power supply device 1 of the present embodiment includes a base 111 made of a magnetic material, a power supply coil L1, and a power supply unit 14 that causes a current to flow through the power supply coil L1 to generate a magnetic flux in the power supply coil L1. The base 111 is formed in a plate shape. The feeding coil L <b> 1 is disposed on the first surface (upper surface) of the base 111 with the central axis directed in the same direction as the thickness direction of the base 111. An inner wall 12 protruding from the first surface (upper surface) of the base 111 along the inner periphery of the power supply coil L1 is provided at a position surrounded by the power supply coil L1 including the central axis. The inner wall 12 is formed such that the area of the storage space 13 surrounded by the inner wall 12 in the same plane as the first surface (upper surface) is larger than the area of the storage space 13 in the same plane as the tip of the inner wall 12.

  The contactless power feeding system of the present embodiment includes a contactless power feeding device 1 and a contactless power receiving device 2 that receives power supplied from the contactless power feeding device 1.

  Since the non-contact power supply device and the non-contact power supply system of the present embodiment are configured as described above, the influence of magnetic flux on the space (storage space 13) surrounded by the power supply coil can be reduced.

  In the non-contact power feeding device 1 of the present embodiment, the area of the storage space 13 on the same surface as the first surface (upper surface) is gradually larger than the area of the storage space 13 on the same surface as the tip of the inner wall 12. The inner wall 12 is preferably inclined with respect to the first surface (upper surface).

  If the non-contact power feeding device 1 of the present embodiment is configured as described above, the range of magnetic flux generated by the power feeding coil L1 can be widened.

  The contactless power supply device 1 according to the present embodiment preferably includes a box-shaped housing 11 having a base 111 as a bottom wall and a part thereof being open, and a cover 15 that covers the opening of the housing 11. It is preferable that the feeding coil L <b> 1 is accommodated in the housing 11. The cover 15 is preferably formed of a nonmetallic material.

  If the non-contact power feeding device 1 of the present embodiment is configured as described above, it is possible to cope with waterproofing and dustproofing in the housing 11.

  In the non-contact power feeding device 1 according to the present embodiment, it is preferable that components constituting at least a part of the power supply unit 14 are arranged in the storage space 13.

  If the non-contact power feeding device 1 of the present embodiment is configured as described above, it is possible to effectively utilize the space (housing space 13) surrounded by the power feeding coil L1.

DESCRIPTION OF SYMBOLS 1 Non-contact electric power feeder 111 Base 12 Inner wall 13 Storage space 14 Power supply part 15 Cover 2 Non-contact electric power receiving device L1 Feed coil

Claims (5)

A base made of a magnetic material; a power supply coil; and a power supply unit that causes a current to flow through the power supply coil to generate a magnetic flux in the power supply coil.
The base is formed in a plate shape,
The feeding coil is disposed on the first surface of the base with a central axis in the same direction as the thickness direction of the base,
An inner wall protruding along the inner periphery of the power supply coil from the first surface of the base is provided at a position surrounded by the power supply coil including the central axis.
The inner wall is formed such that the area of the storage space surrounded by the inner wall on the same surface as the first surface is larger than the area of the storage space on the same surface as the tip of the inner wall. A non-contact power feeding device. The inner wall is inclined with respect to the first surface so that the area of the storage space on the same surface as the first surface is gradually larger than the area of the storage space on the same surface as the tip of the inner wall. The contactless power feeding device according to claim 1, wherein A box-shaped housing having the base as a bottom wall and partially opened; and a cover that covers the opening of the housing;
The feeding coil is housed in the housing,
The contactless power supply device according to claim 1, wherein the cover is made of a non-metallic material. The contactless power feeding device according to any one of claims 1 to 3, wherein a part constituting at least a part of the power supply unit is arranged in the storage space. A non-contact power feeding system comprising: the non-contact power feeding device according to claim 1; and a non-contact power receiving device that receives power supplied from the non-contact power feeding device.

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