JP2008136311A - Composite planar coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planar coil capable of maintaining high efficiency by generating maximum power from a secondary coil side, regardless of the mounted position of the secondary side coil with respect to a primary side coil. <P>SOLUTION: A plurality of coils 1, 2 having different diameters wound inside a plane are disposed coaxially, and the plurality of coils 1, 2 are connected, in series or in parallel with a connecting lead wire 4 to each other. According to such a constitution, the flux density generated becomes uniform, thus enabling transmission of the identical power, independently of the mounting position of the secondary side coil to the primary-side coil. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

    The present invention relates to a power transmission coil used in a power system of, for example, a small electronic device, and more particularly to a composite planar coil in which a plurality of planar coils around which a coil is wound in a plane are arranged in the same plane.

Conventionally, as a heating coil for an electromagnetic cooker, a coil wound in a plane is concentric in the same plane in order to obtain sufficient heating power and a uniform heating pattern regardless of the bottom size of an object to be heated such as a pan. A plurality of arrangements have been proposed (Patent Document 1).
JP-A-8-55678

  However, a coil in which a plurality of planar coils are arranged is not provided for a coil used for power transmission of a small electronic device or the like. And, in the case of a planar coil used for power transmission, assuming the commercialization thereof, the primary coil diameter is made larger than the secondary coil diameter in order to provide a position margin for the secondary coil when transmitting power. Although a method of taking a large power transmission range is used, the primary side coil diameter is large, so that the magnetic flux density is not always constant, and power that can be transmitted is wasted.

  For example, when the primary side coil diameter is about 1.5 times larger than the secondary side coil diameter, the maximum point of the electromotive force generated on the secondary side is not necessarily the center of the primary side coil. The point of deviation is the maximum power. Furthermore, in terms of efficiency, the point with a slight deviation is the maximum. This means that the electric power generated in the secondary side coil changes depending on where the secondary side coil is placed in the primary side coil. Yes.

  The present invention has been made paying attention to such a point. Regardless of the installation position of the secondary coil with respect to the primary coil, the secondary coil side generates maximum power and maintains high efficiency. An object of the present invention is to provide a planar coil that can be used.

  In order to achieve the above-mentioned object, the present invention described in claim 1 is that a plurality of coils having different diameters wound in a plane are arranged concentrically, and the plurality of coils are connected by connecting lead wires. It is a feature. The invention according to claim 2 is characterized in that a plurality of planar coils having different diameters arranged concentrically are connected in series, and the present invention according to claim 3 is a plurality of planar coils having different diameters arranged concentrically. Are connected in parallel.

  In the present invention, a plurality of coils having different diameters wound in a plane are arranged concentrically, and the respective coils are connected in series or in parallel so that the generated magnetic flux density is uniform. Regardless of the installation position of the secondary coil relative to the primary coil, the same power can be transmitted.

  Furthermore, when a plurality of coils having different inductances are arranged in parallel, the power to be transmitted can be controlled by switching the frequency. Further, power can be transmitted to a plurality of portable devices having different powers having different inductances using the same primary coil.

FIG. 1 is a schematic configuration diagram of a primary coil showing an embodiment of the present invention.
This coil is composed of a first coil (1) wound in a donut shape in a plane, a second coil (2) similarly wound in a donut shape in a plane, and a shield material (3). The first coil (1) and the second coil (2) are formed with different diameters.

  The inner diameter of the first coil (1) is formed larger than the inner diameter of the second coil (2), and the second coil (2) is formed in a space portion formed inside the inner diameter of the first coil (1). It is designed to fit in.

  The first coil (1) and the second coil (2) connect the inner end contact of the first coil (1) and the outer end contact of the second coil (2) with a connection lead wire (4). Thus, the first coil (1) and the second coil (2) are positioned in series.

  As a result, as shown in FIG. 2, the electromotive force that decreases at the center of the first coil (1) formed with a large diameter is supplemented with the electromotive force of the second coil (2) formed with a small diameter. Therefore, the electromotive force at the center is made constant. Therefore, when the coil having such a configuration is used as the primary coil of the power transmission coil, it exceeds a certain value over a wide area. Since electric power can be supplied, the electromotive force generated in the secondary coil is stable even if the secondary coil (not shown) is placed eccentrically with respect to the primary coil.

  FIG. 3 shows another embodiment, which is a large-diameter first coil (1) wound in a donut shape in a plane and a small-diameter second coil (donut-shaped) in a plane ( 2) is arranged in a state where the second coil (2) is located in the inner space of the first coil (1), and the inner end contacts and the outer end contacts are respectively connected by connection lead wires (4). Thus, the first coil (1) and the second coil (2) are connected in parallel.

  Thus, when the first coil (1) and the second coil (2) are connected in parallel, the inductances of the first coil (1) and the second coil (2) are different from each other. By switching the frequency, the power to be transmitted can be controlled. As a result, portable devices having different inductances and different powers can be transmitted by the same primary coil.

  INDUSTRIAL APPLICABILITY The present invention can be used as a contactless power transmission coil used for power supply to portable devices and the like.

It is a schematic structure figure showing one embodiment of the present invention. It is a figure which shows the relationship between the distance from a coil center, and an electromotive force. It is a schematic block diagram which shows another embodiment of this invention.

Explanation of symbols

1, 2 ... Coil, 4 ... Connection lead wire.

Claims (3)

A plurality of coils (1) and (2) having different diameters wound in a plane are arranged concentrically, and the plurality of coils (1) and (2) are connected to each other by a connection lead wire (4). Composite planar coil. The composite planar coil according to claim 1, wherein a plurality of coils (1) (2) are connected in series. The composite planar coil according to claim 1, wherein a plurality of coils (1) (2) are connected in parallel.

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