JP2009252970A - Noncontact power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a noncontact power transmission device capable of generating a moving magnetic field, reducing the size and the number of dead points to which power can not be transmitted, and thereby achieving broad-range and stable power transmission. <P>SOLUTION: In this power transmission device 10 transmitting power in a noncontact manner from a primary coil to a secondary coil through a gap 3 by using electromagnetic induction between coils 1 and 2 facing each other, the primary side and the secondary side are composed of a plurality of flat winding type coils 1a, 1b, etc., and one or more flat winding type coils 2a, respectively. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a non-contact power transmission device that transmits power in a non-contact manner, and more particularly to a non-contact power transmission device used in a portable electronic device, a portable electric device, an electronic device, or the like.

  2. Description of the Related Art In recent years, a system that uses an electromagnetic induction effect between opposed coils has been proposed as one of methods for transmitting power from a power source to an electronic device without contact. As such a system, for example, there is a system called a cordless power station or a contactless power station, which is generally abbreviated as CLPS.

  Non-patent documents 1 and 2 describe the configuration of the power transmission side excitation air of such a non-contact power transmission system.

  Non-Patent Document 1 discusses the advantages and disadvantages of different construction methods, the improvement of characteristics by inserting capacitors, the effect of ferrite on the improvement of transmission power and transmission efficiency, and the improvement of transmission characteristics by displacement of the primary and secondary sides. It is what went. Specifically, in the non-contact power transmission apparatus, a connection method is used in which donut-shaped air core coils are arranged on both the primary side and the secondary side, and the directions of magnetic fluxes of adjacent coils are reversed. The reason for this is that the connection method in which the directions of the magnetic fluxes of adjacent coils are opposite to each other intensifies the magnetic flux and the leakage magnetic flux to the outside is greater than the connection method in which the generated magnetic fluxes are all in the same direction. This is because it has the advantage of being less.

In Non-Patent Document 1, when the number of air-core coils is increased on both the primary side and the secondary side, the maximum transmission power P2 _max and the maximum transmission efficiency η _max both increase and a disc-shaped ferrite core is used. In this case, it is disclosed that transmission power can be increased and transmission efficiency can be improved.

  Furthermore, in Non-Patent Document 1, when a capacitor having a capacity obtained from the resonance condition of the secondary coil and the self-inductance of the secondary coil is inserted in series between the secondary coil and the load resistance, the loss is reduced and the transmission efficiency is reduced to about It is stated that it will improve by 10%.

  In Non-Patent Document 1, the amount of power loss and transmission efficiency do not depend on the thickness of the ferrite core and do not depend on the type of ferrite. Has been shown to be advantageous. Further, in Non-Patent Document 1, it has been found that in the case of a coil shape that uses only a magnetic flux component perpendicular to the surface, it is better to match the central axes.

  However, in the non-contact power transmission device disclosed in Non-Patent Document 1, since the primary side and secondary side coils have the same dimensions, there is a large change due to misalignment, and in a wide range of aspects. It has the disadvantage of being inconvenient for any transmission.

In the non-contact power transmission system disclosed in Non-Patent Document 2, one spiral coil is disposed on the power reception side, and a plurality of parallel spiral coils are disposed on the power transmission side, opposite to the opposing surface of each spiral coil. It is the structure which has arrange | positioned the magnetic body thin plate or sheet | seat on the side, respectively. According to the non-contact power transmission system according to Non-Patent Document 2 having such a configuration, on the power receiving side, when the inner diameter / outer diameter ratio (D _i / D _o ) is 0.65, the maximum transmission power is about 70 W, and the inter-coil efficiency is about 65% is obtained. Further, the magnetic coupling coefficient k is greatly involved in the transmission characteristics, and D _i / D _o = 0.65 is the mutual inductance Mc between the power transmission coil and the power reception coil located in the center and the power transmission coil located outside. It is shown that the transmission characteristics are improved in that it is substantially equal to the mutual inductance M0 with the power receiving coil.

  Further, in Non-Patent Document 2, the non-contact power transmission device uses electromagnetic induction between the opposed primary side and secondary side coils, and is not connected from the primary side coil 1 to the secondary side coil 2 via a gap. Power is transmitted by contact.

  In such a non-contact power transmission device, when the capacitor C2 is inserted in parallel with the load so as to cancel the inductive reactance of the coil on the power receiving coil side, a further improvement in efficiency can be seen, and on the back side of the power receiving coil. It has been shown that the fluctuation range of transmission efficiency can be improved by making the shape of the magnetic body further prevent leakage.

  However, in the non-contact power transmission device disclosed in Non-Patent Document 2, the primary side coils are arranged in a plane, and there is a dead point that cannot be transmitted in the plane of transmission by adjacent coils. Therefore, the secondary side coil needs to be larger than the primary side coil. Therefore, the configuration is inconvenient for downsizing of the secondary side.

  Further, in Non-Patent Documents 3 and 4, the non-contact power transmission device has a configuration in which the primary side coil overlaps the adjacent planar coil and the secondary side coil diameter is smaller than the primary side. It has been shown that the transmission fluctuation due to the position is improved by providing a phase difference in the excitation current flowing through. However, this configuration is a configuration in which the primary side planar coils are linearly arranged, and does not suggest a configuration that can be continuously developed in a planar shape.

  Further, Patent Document 1 is the same as Non-Patent Document 1, and the primary side and secondary side coil configurations are the same, and stable transmission becomes difficult due to the coil position deviation.

  In Patent Document 2, a soft magnetic member made of soft magnetic powder and an organic binder is disposed on the outer side of the opposing primary coil and secondary coil, and stable due to misalignment between planar spiral coils. Did not mention the transmission. A combination of a planar spiral coil and a meander coil is shown as a configuration that widens the allowable range of positional deviation.

Junichi Murakami, Hidetoshi Matsuki, Shinki Kikuchi: “Non-contact power transmission characteristics with cordless power station using ferrite”, IEEJ Research Materials, Magnetics Study Group, MAG-95-138, pp. 63-70, 1993 August 2 Published by The Institute of Electrical Engineers of Japan Junichi Hatanaka, Fumihiro Sato, Hidetoshi Matsuki, Shinki Kikuchi, Junichi Murakami, Makoto Kawase, Tadakuni Sato: “Study on the power transmission side excitation configuration of non-positioning non-contact power transmission system”, Journal of Japan Society of Applied Magnetics, Vol. 26, No. 1 580-584 (2002) Jun Miyamori, Akira Haga, Fumihiro Sato, Hidetoshi Matsuki, Tadakuni Sato: “Fundamental study of non-contact power transmission pads for consumer electronics applications”, Proceedings of the 2007 Tohoku Branch Joint Conference on Electrical Engineering, page 354, August 23, 2007 Issued by the Executive Committee of the 2007 Tohoku Branch Association of Electrical Engineers Jun Miyamori, Akira Haga, Fumihiro Sato, Hidetoshi Matsuki, Tadakuni Sato: "Examination of Phase Excitation in Desktop CLPS", 31st Annual Meeting of the Japan Society of Applied Magnetics, 110 (2002), September 11, 2007 Published by Japan Society of Applied Magnetics JP-A-7-231586 JP-A-8-148360

  Therefore, in the non-contact power transmission systems disclosed in Non-Patent Documents 1 to 4, it is possible to reduce and reduce non-transmittable points, and to adjust and adjust the phase difference of excitation current between adjacent coils. Therefore, further improvement is required so that high output and stable power transmission can be achieved in a wider range.

  Therefore, a technical problem of the present invention is to provide a non-contact power transmission device that can realize stable power transmission in a wide range.

  According to the present invention, in an electric power transmission device that uses electromagnetic induction between opposing coils and transmits electric power from a primary side coil to a secondary side coil via a gap, the primary side has three or more. A non-contact power transmission apparatus is obtained in which a planar coil is superimposed and the secondary coil outer diameter is smaller than the primary coil outer diameter.

  According to the present invention, in the non-contact power transmission device, the soft magnetic material is pasted and disposed on the outer side of one or both of the opposing primary side planar coil and secondary side planar coil. A non-contact power transmission apparatus characterized by the above can be obtained.

  According to the present invention, in any one of the contactless power transmission devices, the phase difference of the excitation current flowing in the adjacent coil on the primary side is set to 45 ° to 135 ° or 225 ° to 315 °, and two or more Thus, a non-contact power transmission device can be obtained that generates magnetic fields having different phases.

  According to the present invention, in any one of the non-contact power transmission devices, the soft magnetic material is disposed on the outer side of the secondary planar coil, and the area of the soft magnetic material is increased to the secondary side. A non-contact power transmission device characterized in that the area of the outer diameter of the planar coil is 1.2 times or more can be obtained.

  Furthermore, according to the present invention, in the non-contact power transmission device that includes a power transmission side coil and transmits power by electromagnetic induction to a power reception side coil disposed opposite to the power transmission side coil, the power reception side is used as the power transmission side coil. Three or more planar coils having an outer diameter larger than that of the coil, and these planar coils are two-dimensionally arranged so as to partially overlap the adjacent planar coils, and are phase-shifted to adjacent planar coils. Thus, it is possible to obtain a power feeding device characterized in that excitation currents different from each other flow.

  The non-contact power transmission apparatus described above makes it possible to realize stable power transmission over a wide range.

  The above-mentioned power supply side device of the non-contact power transmission device is configured by superimposing three or more planar coils, and can be continuously expanded in an arbitrary plane, and functions in a wide range. Is obtained.

  In addition, the phase difference of the excitation current flowing in the adjacent coil on the primary side is set to 45 ° to 135 ° or 225 ° to 315 °, and two or more magnetic fields having different phases are generated, thereby providing stable power supply in a wide range. A contactless power transmission device is obtained.

  According to the present invention, in any one of the non-contact power transmission devices, a soft magnetic material is provided on one or both of the opposing primary side planar coil and secondary side planar coil. A high output non-contact power transmission device can be obtained by sticking and arranging.

  In addition, by making the area of the soft magnetic material arranged in the secondary side planar coil 1.2 times or more the area of the secondary side planar coil outer diameter, high output non-contact power transmission over a wider range A device is obtained.

  Hereinafter, embodiments of the present invention will be described.

  The non-contact power transmission device of the present invention uses electromagnetic induction between opposing coils to transmit power from the primary coil to the secondary coil in a non-contact manner via a gap. In this power transmission device, the primary side is configured to be planarly arranged by superimposing (partially overlapping) three or more planar coils, and the secondary side is configured by one or more planar coils. The outer diameter of the secondary coil (the outer diameter of the secondary planar coil) is smaller than the outer diameter of the primary coil (the outer diameter of the primary planar coil). The planar coil is not limited to a circular shape as long as it is a planar type, but may be a polygonal shape, but is preferably a planar winding coil.

  In the non-contact power transmission device of the present invention, either one of the opposing primary side planar coil and the secondary side planar coil, or the outer side of both (also referred to as the opposite side of the opposing surface, also referred to as the back surface) By disposing the soft magnetic material, the magnetic coupling between the primary side coil and the secondary side coil can be improved by the convergence effect of the generated magnetic field, which can contribute to the improvement of the output.

  In the non-contact power transmission device, the phase difference of the excitation current flowing in the adjacent coil on the primary side is set to 45 ° to 135 ° or 225 ° to 315 °, and two or more magnetic fields having different phases are generated. A moving magnetic field can be generated, and high transmission efficiency can be obtained over a wide range of the feeding side surface.

  When a soft magnetic material is disposed on the outer side of the secondary side planar coil, the area of the soft magnetic material is set to 1.2 times or more of the area of the outer diameter of the secondary side planar coil. High transmission efficiency can be obtained in a wider range of side surfaces.

  In addition, the present invention is configured so that the secondary side coil is smaller than the primary side coil so that it is useful in non-contact transmission to an electronic device or the like, particularly in application to a portable device. It is intended to reduce the weight.

  Further, the power feeding side (primary side) of the present invention can arbitrarily increase the transmission area, and a plurality of power receiving sides (secondary side) can transmit power.

(Other embodiments)
A power supply apparatus according to another embodiment of the present invention is used as, for example, a charger for a portable electronic device. Since the power receiving coil included in the portable electronic device serves as the secondary coil, this non-contact power transmission device does not include the secondary coil.

  The power supply apparatus has three or more planar coils having an outer diameter larger than the outer diameter of the power receiving coil as power transmission (primary side) coils. These planar coils are two-dimensionally arranged so as to partially overlap the adjacent planar coils. This arrangement is performed, for example, so that a straight line connecting the centers of adjacent planar coils forms an equilateral triangle on a dielectric material plate or sheet.

  In addition, exciting currents having different phases are supplied to the planar coils adjacent to each other. The phase difference is preferably within a range of 45 ° to 135 ° or 225 ° to 315 °, and particularly preferably 90 ° or 270 °.

  Embodiments of the present invention will be described below with reference to the drawings.

Example 1
In Embodiment 1 of the present invention, a basic configuration of a non-contact power transmission apparatus will be described.

  FIG. 1 is a perspective view mainly showing an example of the arrangement of coils of the non-contact power transmission apparatus according to the first embodiment of the present invention.

  As shown in FIG. 1, the non-contact power transmission device 10 uses electromagnetic induction between the opposed primary side and secondary side coils 1 and 2, and passes from the primary side coil 1 to the secondary side coil via the gap 3. 2 to transmit power without contact. The primary coil 1 is provided with a plurality of planar winding coils 1a, 1b, 1c, 1d and 1f, and the secondary coil 2 is provided with one or more planar winding coils 2a. A soft magnetic material plate or sheet 4 is attached to the back surface (outer surface) of the primary coil 1. Further, a similar soft magnetic material plate or sheet 4 can also be attached to the back surface (outer surface) of the secondary coil 2. In the above example, the coils used for the primary coil 1 and the secondary coil 2 are both planar winding coils. However, the coils are not limited to circular planar coils, and may be polygonal coils. Of course, the effects of the present invention can be obtained.

  In the above example, the plate or sheet 4 made of a soft magnetic material is disposed on the opposite coil back surface. However, this magnetic material has an effect of converging the generated magnetic field, and the primary coil 1 and the secondary coil 1 are secondary. This improves the magnetic coupling of the side coil 2 and contributes to an improvement in output.

  A non-contact power transmission apparatus 10 shown in FIG. 1 includes a primary coil 1 having a plurality of planar winding coils 1a, 1b, 1c, 1d, 1e and 1f, and a secondary coil 2 having one or more planar winding coils. 2a. The outer diameter (secondary coil outer diameter) of the planar winding coil 2a is smaller than the outer diameter (primary coil outer diameter) of the planar winding coil 1a, 1b, 1c, 1d, 1e or 1f. . This non-contact power transmission device 10 differs from the non-contact power transmission device according to the prior art in that the number of planar winding coils 1a, 1b,. Another difference is that the outer diameter of the wound coil 2a is smaller than the outer diameter of the primary coil.

(Example 2)
In Example 2 of the present invention, measurement of specific characteristics of a non-contact power transmission device when a soft magnetic material is disposed will be described.

  As shown in FIG. 1, the primary side coil and the secondary side coil are arranged so as to face each other in the axial direction. The primary coil was composed of three planar winding coils each having an outer diameter of 70 mm, an inner diameter of 20 mm, and 81 turns. The central axes of the adjacent planar winding coils are arranged at an angle of 60 ° on the plane, and three coil winding portions are superposed. The secondary coil had an outer diameter of 30 mm, an inner diameter of 15 mm, and 11 turns.

And with the central axes of the primary coil 1 and the secondary coil 2 aligned, the gap between the coils is 1 mm, and the soft magnetic material is arranged on both the primary and secondary sides. only, only the secondary side, and no attachment, as shown in FIG. 2, the primary-side flat wire-wound coil _L 1-1 of the coil _1, the power P1, P2 and P3 in _{L 1-2} and _{L 1-3} On the other hand, a capacitor C ₂ , a rectifier 21, a DC / DC converter 22, and a variable resistor R _load are connected to the planar coil L ₂ of the secondary side coil to constitute a measurement circuit (LCR meter). did. Then, the power supplies P1, P2 and P3 were set to a frequency of 120 kHz and a constant current of 50 mA, the inductance was measured with an LCR meter, and the magnetic coupling coefficient k was obtained. The soft magnetic material is a MnZn ferrite sintered body having a thickness of 0.5 mm, and the one attached to the secondary coil 2 is about 1.1 times the outer diameter area of the coil.

  The results are shown in Table 1 below.

  As is apparent from Table 1, the magnetic coupling coefficient k is clearly improved and the transmission power is improved by arranging the soft magnetic material.

(Example 3)
In the arrangement configuration of the primary side coil 1 and the secondary side coil 2 as in the second embodiment, the secondary side coil 2 is moved above the primary side coil 1, and the transmission efficiency to the secondary side coil 2 depending on the position. Was measured. Here, on the primary side, the frequency is 120 kHz, 18 V, the load resistance is 10Ω, and the phase of the excitation current flowing through the adjacent coils L _1-1 , L _1-2 and L _1-3 is variable.

  The transmission efficiency changed according to the position of the secondary coil on the primary coil 1. The maximum value and the minimum value at this time are shown in Table 2 as the relationship with the current phase difference (= α = β−α) between adjacent coils.

  By providing a phase difference in the exciting current flowing in the adjacent overlapping coils, the region where the transmission efficiency is reduced is improved. By setting the phase difference to 45 to 135 ° or 225 to 315 °, the minimum transmission efficiency tends to be clearly improved.

  Incidentally, at the position of maximum transmission efficiency, the output is 3 W.

  Further, when the phase difference of the excitation current flowing in the adjacent overlapping coils is set to 60 ° and 120 °, the area where the maximum transmission efficiency is obtained at the position on the plane of the primary coil occupies about 95%. .

  It was also confirmed that the area where the transmission efficiency is lowered clearly decreases by increasing the area of the ferrite flat plate attached to the secondary coil. Incidentally, by making the area of the ferrite plate 1.2 times the outer diameter area of the secondary coil, the transmission efficiency was 75% or more over almost the entire surface.

It is a perspective view which mainly shows an example of arrangement | positioning of the coil of the non-contact electric power transmission apparatus by Example 1 of this invention. It is a circuit diagram which shows the structural example of the measuring circuit of the non-contact electric power transmission apparatus by Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Primary coil 1a, 1b, 1c, 1d, 1e, 1f Planar winding type coil 2 Secondary side coil 2a Planar winding type coil 3 Air gap 4 Plate or sheet made of soft magnetic material 10 Non-contact power transmission device 21 Rectifier 22 DC / DC converter

Claims (8)

  In a power transmission device that uses electromagnetic induction between opposing coils and transmits power in a non-contact manner from a primary coil to a secondary coil via a gap, three or more planar coils are superimposed on the primary side. The non-contact power transmission device is characterized in that the outer diameter of the secondary coil is smaller than the outer diameter of the primary coil.   The contactless power transmission device according to claim 1, wherein a soft magnetic material is disposed on an outer portion of one or both of the opposing primary side planar coil and secondary side planar coil. Non-contact power transmission device.   The contactless power transmission device according to claim 1 or 2, wherein the phase difference of the excitation current flowing through the adjacent coil on the primary side is 45 ° to 135 ° or 225 ° to 315 °, and two or more magnetic fields having different phases are provided. Generating a non-contact power transmission device.   The contactless power transmission device according to any one of claims 1 to 3, further comprising a soft magnetic material disposed on an outer side of the secondary planar coil, wherein the area of the soft magnetic material A non-contact power transmission device characterized in that the area of the outer diameter of the side plane coil is 1.2 times or more. In a power feeding device that includes a power transmission side coil and transmits power by electromagnetic induction to a power reception side coil disposed opposite to the power transmission side coil.
The power transmission side coil has three or more planar coils having an outer diameter larger than that of the power reception side coil, and these planar coils are two-dimensionally arranged so as to partially overlap the adjacent planar coils. An electric power feeding device characterized in that exciting currents having different phases are allowed to flow through adjacent planar coils. In the electric power feeder of Claim 5,
The power feeding apparatus, wherein the planar coil is arranged so that a line connecting the centers of the adjacent planar coils forms an equilateral triangle.   7. The power feeding apparatus according to claim 5, wherein the excitation currents having different phases have a phase difference of 45 [deg.] To 135 [deg.] Or 225 [deg.] To 315 [deg.].   8. The power feeding device according to claim 5, further comprising a soft magnetic plate or sheet on a back side of the power transmission side coil. 9.

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