JP2012134248A - Resonance coil and non-contact power transmission device with resonance coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact and inexpensive resonance coil in which there is no dielectric breakdown between coil conductors, and to provide a non-contact power transmission device equipped with the resonance coil.SOLUTION: The resonance coil 50 includes a coil conductor 51 having multiple number of turns and used for transmitting power to a partner coil by resonance phenomenon and receiving power transmitted from the partner coil, and a mold member 52 including the coil conductor 51. Between one turn 55[k] of the coil conductor 51 and other turn 55[k+1] contiguous to the one turn 55[k], an interconductor gap G having a size according to a potential difference between the one turn 55[k] and other turn 55[k+1] is provided.

Description

  The present invention relates to a resonance coil that transmits power to a counterpart coil or receives power transmitted from the counterpart coil by a resonance phenomenon, and a non-contact power transmission apparatus having the resonance coil.

  In recent years, for example, charging of a secondary battery (hereinafter simply referred to as “battery”) included in an electric vehicle or the like is wireless (non-contact) that does not require physical connection such as plug connection in order to facilitate charging work. ) Is used.

  As such wireless power transmission technology, an electromagnetic induction method using an electromagnetic induction phenomenon, an electromagnetic wave transmission method using an electromagnetic wave, a resonance method using a resonance phenomenon, and the like are known. Among them, the resonance method is a technique for transmitting electric power by supplying AC power to the transmission resonance coil and causing the transmission resonance coil to resonate with the reception resonance coil disposed opposite to the transmission resonance coil via an electromagnetic field. It is possible to transmit large power of several kW between relatively distant places.

  However, when such a resonance-type wireless power transmission technology is applied to a system in which large power of several kW to several tens of kW is transmitted, such as a battery charging system of an electric vehicle, for example, as shown in FIG. When the resonance state is reached, a high voltage is generated at or near the end of the coil wire wound in the tubular shape of the resonance coil, and dielectric breakdown occurs between the resonance coil and the grounded case that houses the resonance coil. There were problems such as the occurrence of spark discharge. And the technique which solves such a problem is disclosed by patent document 1, for example.

  As shown in FIG. 8, the resonance coil 901 disclosed in Patent Document 1 includes a coil conductor 910 and an insulating resin 920. The coil conducting wire 910 is wound in a tubular shape a plurality of times. And since this insulating resin 920 is coated on the coil conductor 910 so that the thickness increases as the length of the end 910a in the longitudinal direction of the coil conductor 910 increases, the dielectric strength at the end 910a of the coil conductor 910 is increased. It was possible to prevent spark discharge. In addition, the coil conductor 910 of the resonance coil 901 has a certain inter-conductor gap between the winding portions of the coil conductor 910, and spark discharge due to dielectric breakdown between the winding portions of the coil conductor 910. It was preventing.

JP 2010-73885 A

  For example, in a battery charging system for an electric vehicle, the resonance coil is required to be miniaturized in order to improve fuel efficiency, secure a space in the vehicle, and effectively use a charging area. However, in the resonance coil having the above-described configuration, the size of the gap between the conductors of the coil conductor is the largest even though the potential difference generated between the winding portions of the coil conductor differs depending on the location of the coil conductor as can be seen from FIG. Since it is made constant according to the large potential difference, the gap between the conductors becomes larger than necessary at the location where the potential difference is lower than this, and there is a problem that a wasteful portion is generated and the size cannot be reduced. It was. Or, if the resonance coil is downsized, the gap between the windings of the coil conductor becomes smaller, so in order to prevent dielectric breakdown between the windings of the coil conductor, a resin with high insulation performance is coated on the coil conductor coating. There is a problem that the manufacturing cost increases because measures such as use or increasing the thickness of the resin are required.

  The present invention aims to solve the above problems. That is, an object of the present invention is to provide a small and inexpensive resonant coil that does not cause dielectric breakdown between coil conductors and a non-contact power transmission device including the same.

  As a result of repeated investigations on the configuration of the resonance coil in order to achieve both reduction in size and cost of the resonance coil, the present inventor has produced different potential differences between the winding portions of the coil conductor. It has been found that by providing a gap between the conductors of an appropriate size according to the potential difference between them, it is possible to realize low cost while having a small shape, and the present invention has been completed.

  In order to achieve the above object, the invention described in claim 1 is a resonance coil that transmits electric power to a counterpart coil by a resonance phenomenon or receives electric power transmitted from the counterpart coil. And between the one winding part of the coil conductor and another winding part adjacent to the one winding part, the one winding part and the other winding part. The resonance coil is characterized in that a gap between conductors having a size corresponding to a potential difference generated between the winding portion and the winding portion is provided.

  The invention described in claim 2 is the invention described in claim 1, wherein the coil conductor is wound in a tubular shape a plurality of times, and the gap between the conductors in the central portion in the axial direction of the coil conductor is large. Is larger than the size of the gap between the conductors at both ends in the axial direction of the coil conductor.

  The invention described in claim 3 is characterized in that, in the invention described in claim 1 or 2, the coil conductor is provided with an insulating coating member covering the surface thereof.

  The invention described in claim 4 is the invention described in any one of claims 1 to 3, further comprising an insulating member provided so as to fill the gap between the conductors and enclose the coil conductor. It is characterized by that.

  In order to achieve the above object, the invention described in claim 5 includes a transmission resonance coil that transmits electric power by a resonance phenomenon and a reception resonance coil that receives electric power transmitted from the transmission resonance coil. In the contact power transmission device, at least one of the transmission resonance coil and the reception resonance coil is the resonance coil according to any one of claims 1 to 4, wherein the contact power transmission device is a non-contact power transmission device. .

  According to the first aspect of the present invention, the coil conductor is wound a plurality of times, and one winding portion of the coil conductor and another winding portion adjacent to the one winding portion are provided. Is provided with a gap between the conductors having a size corresponding to the potential difference generated between the one winding part and the other winding part. In the configuration in which a constant gap between conductors having a size corresponding to the largest potential difference generated between the coil conductors is provided as described above, an excessively large gap between conductors is formed at a location where the potential difference is small, and the resonance coil is small. However, in the present invention, by providing an inter-conductor gap having a size that matches the potential difference generated between the winding portions of the coil conductor, an inter-conductor gap having an excessive size can be obtained by setting the inter-conductor gap to an appropriate size. Can be lost, carp It can provide an inexpensive resonance coil compact without dielectric breakdown between turns.

  According to the invention described in claim 2, the coil conductor is wound in a tubular shape a plurality of times, and the size of the gap between the conductors in the axial central portion of the coil conductor is equal to both axial ends of the coil conductor. In the resonance coil having the characteristic that the potential difference generated between the winding portions of the coil conductor is large at the axial center of the tubular coil conductor and is small at both ends, the gap between the coil conductors is larger than the gap between the conductors. A small and inexpensive resonance coil without dielectric breakdown can be provided.

  According to the invention described in claim 3, since the coil conductor is provided with the insulating coating member that covers the surface thereof, the dielectric strength between the winding portions is improved and the size of the gap between the conductors is further increased. Therefore, the resonance coil can be further reduced in size.

  According to the fourth aspect of the present invention, since the insulating member is provided so as to fill the gap between the conductive wires and enclose the coil conductive wire, the dielectric strength between the respective winding portions is improved and the conductive wire is provided. The size of the gap can be further reduced, and the resonance coil can be further miniaturized.

  According to the invention described in claim 5, since at least one of the transmission resonance coil and the reception resonance coil is the resonance coil described in any one of claims 1 to 4, a small and inexpensive resonance coil is provided. Can be used to provide a small and inexpensive contactless power transmission device.

It is a perspective view which shows one Embodiment of the resonance coil of this invention. It is a side view of the coil conducting wire which the resonance coil of FIG. 1 has. It is a figure which shows the structure of the modification of the resonance coil of FIG. 1, Comprising: (a) is a front view of a round planar coil, (b) is a front view of a square planar coil. It is explanatory drawing which shows the structure of the wireless power transmission apparatus which concerns on one Embodiment of the non-contact power transmission apparatus of this invention. It is a block diagram of the wireless power transmission apparatus of FIG. It is explanatory drawing which shows the principle of a resonance-type electric power transmission system. It is a figure which shows typically the voltage distribution in the resonance state in a coil conducting wire. It is a partial expanded sectional view which shows the structure of the conventional resonance coil.

(One Embodiment of Resonance Coil)
Hereinafter, an embodiment of a resonance coil of the present invention will be described with reference to FIGS.

  The resonance coil is used to transmit power to or receive power transmitted from the counterpart coil by using a resonance phenomenon.

  The resonance coil according to the present invention shown in each drawing (indicated by reference numeral 50 in the drawings) includes a coil conductor 51 and a mold member 52 as an insulating member.

  As shown in each drawing, the coil conductor 51 is, for example, an air-core spiral coil having a diameter D of 600 mm and a length L of 200 mm, in which a copper wire having a diameter of 5 mm is wound around a tubular (solenoid) a plurality of times (n times). It is. The coil conductor 51 is provided with winding portions 55 [1] to 55 [n] which are a plurality of circular portions (one turn). Between one winding part 55 [k] of the coil conducting wire 51 and another winding part 55 [k + 1] (k: 1 to n−1) adjacent thereto (hereinafter simply referred to as between the winding parts 55). Corresponds to the potential difference between the winding portions 55, that is, between the conductors of the minimum size necessary to prevent dielectric breakdown between the winding portions 55 even when this potential difference occurs. A gap G is provided. The size of the gap G between the conductors is determined according to the voltage distribution of the coil conductor 51 in the resonance state.

  FIG. 7 shows the voltage distribution of the coil conductor 51 in the resonance state. As is clear from FIG. 7, the potential difference between unit distances in the coil conductor 51 (ie, the slope of the graph) is larger at the central portion in the longitudinal direction of the coil conductor 51 (ie, the origin of the graph). It gets smaller as it gets closer to the part. That is, the coil conductor 51 wound in a tubular shape has a different potential difference between the winding portions 55 depending on the location. Specifically, the central portion in the axial direction (that is, the length L direction) is between the winding portions 55. The potential difference is large, and the potential difference between the winding portions 55 becomes smaller as it approaches the both ends in the axial direction.

  From this, the size of the inter-conductor gap G of the coil conductor 51 wound in a tubular shape is gradually increased from the axial central portion of the coil conductor 51 toward both axial ends as shown in each drawing. It is provided to be smaller. In other words, the inter-conductor gap G at the central portion in the axial direction of the coil conductor 51 is provided to be larger than the inter-conductor gap G at both end portions in the axial direction.

  The mold member 52 is made of, for example, a synthetic resin having a high withstand voltage such as PI (polyimide) or PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer). It is provided so as to fill the gap G between the conductors and enclose the coil conductor 51 by being poured into a cuboid frame mold in which the whole is accommodated in a molten state and then solidified. The dielectric breakdown voltage (AC) of the mold member 52 is about 15 to 20 [kV / mm] in PI and about 150 [kV / mm] in PFA, while the dielectric breakdown voltage (AC) of air. Is about 3 [kV / mm], and by providing such a mold member 52, the size of the gap G between the conducting wires can be further reduced.

  In the present embodiment, an inter-conductor gap G having an appropriate size is provided in accordance with the potential difference generated between the winding portions of the coil conductor 51. On the other hand, in the case of the conventional configuration, for example, when the sizes of the gaps G between the conducting wires are all the same, the magnitude is the potential difference between the winding portions 55 in the central portion in the axial direction of the coil conducting wire 51, that is, Since it is determined in accordance with the largest potential difference, the size of the gap G between the conductors becomes excessive at both ends of the coil conductor 51 in the axial direction, resulting in useless portions.

  And according to this embodiment, about the gap G between conducting wires, the magnitude | size of the gap G between conducting wires is made small in the axial direction both ends of the coil conducting wire 51 where the electrical potential difference between the winding parts 55 is comparatively low, and winding part In the central portion in the axial direction of the coil conductor 51 having a relatively high potential difference between 55, by increasing the size of the inter-conductor gap G, an inter-conductor gap G having a size corresponding to the potential difference between the winding portions 55 is provided. Realized miniaturization.

  As described above, according to the present invention, the coil conductor 51 is wound a plurality of times, and one coiled portion 55 [k] of the coil conductor 51 and the one coiled portion 55 [k] are provided. Between the adjacent other winding portions 55 [k + 1], a conductor having a size corresponding to a potential difference generated between the one winding portion 55 [k] and the other winding portion 55 [k + 1]. Since the gap G is provided, for example, in the configuration in which a constant gap between conductors having a size corresponding to the largest potential difference generated between the coil conductors is provided as in the resonance coil of Patent Document 1 described above, In places where the potential difference is small, the gap between the conductors becomes excessively large and the resonance coil cannot be reduced in size. Such an excessive You can eliminate the wires between the gap of can, can realize an inexpensive resonance coil 50 in a small no dielectric breakdown between the coil wires 51.

  In addition, the coil conductor 51 is wound in a tubular shape a plurality of times, and the size of the gap G between the conductors in the axial center of the coil conductor 51 is equal to the gap G between the conductors G at both axial ends of the coil conductor 51. In the resonance coil 50 having a characteristic that the potential difference generated between the winding portions 55 of the coil conductor 51 is large at the axial center portion of the tubular coil conductor 51 and becomes small at both ends in the axial direction. It is possible to realize a small and inexpensive resonance coil without insulation breakdown between the two.

  Moreover, since it has the mold member 52 which consists of an insulator provided so that the gap G between conductors may be filled and to enclose the coil conductor 51, the dielectric breakdown tolerance (dielectric strength) between the coil conductors 51 improves. Thus, the size of the gap G between the conducting wires can be further reduced, and the resonance coil can be further downsized.

  In the present embodiment, the coil conductor 51 is composed only of a copper wire. However, the present invention is not limited to this. For example, the coil conductor 51 includes a coil made of PI, PFA, or the like. An insulating covering member that covers the surface of the conducting wire 51 may be provided. By doing in this way, the dielectric strength of the coil conducting wire 51 can be improved, the size of the gap G between the conducting wires can be further reduced, and the resonance coil can be further downsized. Moreover, in this embodiment, although it has the mold member 52, it is not limited to this, The structure which does not have the mold member 52 may be sufficient.

  In addition, the coil conductor 51 of the present embodiment is wound in a tubular shape a plurality of times, and the gap G between the conductors is provided so as to gradually decrease from the axial center of the coil conductor 51 toward both axial ends. However, the present invention is not limited to this. For example, as shown in FIGS. 3A and 3B, the gap G between the conductors is in the center in the radial direction (the direction in which the gap spreads radially from the center). The coil conductor 51 may be a flat spiral coil or the like in which the coil conductor 51 is wound a plurality of times in a flat shape so as to gradually decrease from the portion toward the inner edge and the outer edge, and does not contradict the purpose of the present invention. As long as the gap G between conductors of the magnitude | size according to the electric potential difference which arises between each winding part 55 of the coil conducting wire 51 is provided, what is necessary is just.

(One Embodiment of Non-contact Power Transmission Device)
Next, a wireless power transmission device according to an embodiment of the non-contact power transmission device of the present invention provided with the above-described resonance coil will be described with reference to FIGS.

  FIG. 4 is an explanatory diagram showing the configuration of the wireless power transmission device according to the embodiment of the present invention. As shown in the figure, a wireless power transmission device 10 according to the present embodiment includes a power receiving device 12 provided in an electric vehicle 5 and a power feeding device 11 that supplies AC power to the power receiving device 12. The AC power output from the power feeding device 11 is transmitted to the power receiving device 12 in a non-contact (wireless) manner. The power feeding device 11 includes a communication coil 24 for power transmission. When AC power is supplied to the communication coil 24, the AC power is supplied to the power reception communication coil 31 provided in the power receiving device 12. Is transmitted to.

  The power receiving device 12 provided in the electric vehicle 5 includes a power receiving communication coil 31 that approaches the power transmitting communication coil 24 and a rectifier 33 when the electric vehicle 5 is placed at a predetermined position of the power feeding device 11 during charging. And. Furthermore, a battery 35 charged with DC power, a DC / DC converter 42 that steps down the voltage of the battery 35 and supplies it to the sub-battery 41, an inverter 43 that converts output power of the battery 35 into AC power, A motor 44 driven by AC power output from the inverter 43 is provided.

  FIG. 5 is a block diagram of the wireless power transmission device 10 according to the embodiment of the present invention, which includes a power feeding device 11 and a power receiving device 12 mounted on the electric vehicle 5.

  The power supply apparatus 11 is amplified by a carrier oscillator 21 that outputs a carrier signal for power transmission, a power amplifier 23 that amplifies the carrier signal (that is, AC power) output from the carrier oscillator 21, and the power amplifier 23. A communication coil 24 that outputs AC power is provided. As will be described later, the communication coil 24 includes a feeding coil (primary coil) L1 and a transmission resonance coil X1. And the resonance coil 50 mentioned above is used as this transmission resonance coil X1.

  The carrier oscillator 21 outputs, for example, AC power having a frequency of 1 to 100 [MHz] as an AC signal for power transmission.

  The power amplifier 23 amplifies the AC power output from the carrier transmitter 21. Then, the amplified AC power is output to the communication coil 24. The communication coil 24 cooperates with the communication coil 31 provided in the power receiving device 12 and wirelessly transmits AC power to the communication coil 31 by a resonance type power transmission method. The resonance type power transmission method (that is, the resonance method) will be described later.

  The power receiving device 12 rectifies the AC power received by the communication coil 31 and receives the AC power transmitted from the power transmission communication coil 24, and rectifies the DC voltage. And a rectifier 33 to be generated. Further, a battery 35 that supplies electric power to a vehicle driving motor 44 (see FIG. 4) is provided, and the battery 35 is charged by DC power output from the rectifier 33.

  As will be described later, the communication coil 31 includes a power receiving coil (primary coil) L2 and a receiving resonance coil X2. The above-described resonance coil 50 is used as the reception resonance coil X2.

  Next, the resonance type power transmission method will be described. FIG. 6 is an explanatory diagram showing the principle of the resonant power transmission method. As shown in the figure, the power feeding device 11 is provided with a power feeding coil L1 and a transmission resonance coil X1 (that is, a resonance coil 50) that is disposed concentrically and in proximity to the power feeding coil L1. The power supply coil L1 and the transmission resonance coil X1 constitute the communication coil 24 shown in FIGS. In addition, the power receiving device 12 is provided with a power receiving coil L2 and a receiving resonance coil X2 (that is, a resonance coil 50) disposed concentrically and in proximity to the power receiving coil L2. The power receiving coil L2 and the receiving resonance coil X2 constitute the communication coil 31 shown in FIGS.

  When a primary current is passed through the feeding coil L1, an induced current flows through the transmission resonance coil X1 by electromagnetic induction, and the transmission resonance coil X1 resonates due to the inductance Ls and the stray capacitance Cs of the transmission resonance coil X1. Resonates at a frequency ωs (= 1 / √Ls · Cs). Then, the reception resonance coil X2 on the power receiving device 12 side provided near the transmission resonance coil X1 resonates at the resonance frequency ωs, and a secondary current flows through the reception resonance coil X2. Further, a secondary current flows through the power receiving coil L2 close to the receiving resonance coil X2 due to electromagnetic induction.

  With the above operation, power can be transmitted from the power feeding device 11 to the power receiving device 12 wirelessly.

  Next, the operation of the wireless power transmission device of the present invention shown in FIGS. 4 and 5 will be described. As shown in FIG. 4, the electric vehicle 5 is placed at a predetermined position of the power feeding device 11, and the communication coil 24 provided in the power feeding device 11 and the communication coil 31 provided in the power receiving device 12 of the electric vehicle 5 are opposed to each other. Then, the battery 35 can be charged.

  When charging is started, AC power having a frequency of about 1 to 100 [MHz] is output from the carrier oscillator 21 shown in FIG.

  Then, the AC power output from the carrier transmitter 21 is amplified by the power amplifier 23. The amplified AC power is transmitted to the power receiving device 12 through the communication coils 24 and 31 based on the principle of the resonance power transmission described above.

  The AC power transmitted to the power receiving device 12 is output from the communication coil 31 to the rectifier 33.

  The rectifier 33 rectifies AC power and converts it into DC power of a predetermined voltage, supplies this power to the battery 35, and charges the battery 35. Thereby, the battery 35 can be charged.

  As described above, according to the present invention, since the above-described resonance coil 50 is used as the transmission resonance coil X1 and the reception resonance coil X2, one winding portion 55 [k] of the coil conductor 51 of the resonance coil 50 and Between the other winding portions 55 [k + 1] adjacent to the winding portion 55 [k + 1], the size of the winding portion 55 [k + 1] is different from that of the one winding portion 55 [k + 1]. An inter-conductor gap G is provided, so that an excessively large inter-conductor gap can be eliminated, and the transmission resonance coil X1 and the reception resonance coil X2 can be reduced in size at low cost. A contact power transmission device can be provided.

  In the present embodiment, the resonance coil 50 described above is used for both the transmission resonance coil X1 and the reception resonance coil X2. However, the present invention is not limited to this, and at least one of the transmission resonance coil X1 and the reception resonance coil X2 is used. Any one using the resonance coil 50 may be used.

  In addition, embodiment mentioned above only showed the typical form of this invention, and this invention is not limited to embodiment. That is, various modifications can be made without departing from the scope of the present invention.

5 Electric vehicle 10 Wireless power transmission device (non-contact power transmission device)
50 Resonant coil 51 Coil conductor 52 Mold member (insulating member)
55 winding part X1 transmission resonance coil (resonance coil)
X2 receiving resonance coil (resonance coil)

Claims (5)

A resonance coil that transmits power to a counterpart coil by a resonance phenomenon or receives power transmitted from the counterpart coil,
Having a coil wire wound several times; and
Between the one winding part of the coil conductor and the other winding part adjacent to the one winding part, there is a potential difference generated between the one winding part and the other winding part. A resonance coil having a gap between conductors of a corresponding size. The coil conductor is wound into a tube a plurality of times;
2. The resonance coil according to claim 1, wherein a size of the gap between the conductors in an axially central portion of the coil conductor is larger than a size of the gap between the conductors in both axial ends of the coil conductor.   The resonance coil according to claim 1, wherein the coil conductor is provided with an insulating covering member that covers a surface thereof.   The resonance coil according to any one of claims 1 to 3, further comprising an insulating member provided so as to be filled in the gap between the conductive wires and to enclose the coil conductive wire. In a non-contact power transmission apparatus having a transmission resonance coil that transmits power by a resonance phenomenon, and a reception resonance coil that receives power transmitted from the transmission resonance coil,
5. The contactless power transmission device according to claim 1, wherein at least one of the transmission resonance coil and the reception resonance coil is the resonance coil according to claim 1.

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