JP2009206169A - Plane coil, electric instrument using the same, power supply unit, and non-contact power transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plane coil which can be made thin while reducing high-frequency loss, to provide an electric instrument using the same, to provide a power supply unit, and to provide a non-contact power transmission system. <P>SOLUTION: Plane coils 20 and 30 are each configured by disposing a flat plate-like conductor portion 4 in a spiral state. Further, a plurality of openings 7 are provided along the longitudinal direction of the conductor portion of the plane coil. The electric instrument includes the plane coil and a load circuit driven according to a voltage induced at the plane coil through electromagnetic induction. The power supply unit includes the plane coil and a high-frequency current supply portion which supplies a high-frequency current to the plane coil. The non-contact power transmission system includes the power supply unit and the electric instrument. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a planar coil used at a high frequency. And it is related with the electric equipment, electric power supply apparatus, and non-contact electric power transmission system which use such a planar coil.

  Conventionally, in a non-contact power transmission device that transmits power by electromagnetic induction without contact, a general coil used for power transmission is made by winding a metal wire (copper wire) or a metal plate (copper plate). However, in such a general coil, a high frequency loss occurs due to an effect such as a proximity effect that occurs when a high frequency current flows through the coil, and power transmission efficiency decreases.

In order to reduce such high-frequency loss, a power transmission device using a litz wire as a coil is known (see, for example, Patent Document 1).
JP 2006-230032 A

  However, when a litz wire is used for the coil, there is a disadvantage that the thickness of the coil increases. Further, when the thickness of the coil increases, it is difficult to reduce the thickness of an electric device using such a coil and a power supply device that supplies electric power to such an electric device in a non-contact manner. It was.

  The present invention has been made in view of such circumstances, and includes a planar coil that can be reduced in thickness while reducing high-frequency loss, and an electric device, a power supply device, and a non-contact power transmission system using the same. The purpose is to provide.

  The planar coil according to the present invention is a planar coil in which flat conductor portions are arranged in a spiral shape, and a plurality of openings are provided along the longitudinal direction of the conductor portions.

  According to this configuration, the space where the eddy current can be generated on the conductor portion is reduced by the plurality of openings provided in the conductor portion of the planar coil, and the loop of the eddy current is reduced. As a result, eddy current loss is reduced, and high-frequency loss in the planar coil is reduced. Also, since the conductor portion is provided with a plurality of openings along the longitudinal direction of the conductor portion, that is, the direction of current flow, the direction of the current flowing through the plurality of openings is scattered, resulting in a proximity effect. The high frequency loss is reduced. Thereby, high frequency loss can be reduced in a thin planar coil in which flat conductor portions are arranged in a spiral shape.

  The plurality of openings are provided in a plurality of rows extending in the longitudinal direction of the conductor portion, and adjacent openings in the plurality of rows are alternately arranged. Is preferred.

  According to this configuration, among the openings formed in a plurality of rows, the openings in adjacent rows are alternately arranged, so that the degree of current scattering is increased, resulting in the openings being staggered. The proximity effect is reduced and the high-frequency loss is reduced as compared with the case where it is not.

  Further, it is preferable that the plurality of openings are provided so that an area ratio of the plurality of openings per unit area in the conductor portion increases as the area approaches the center of the spiral.

  According to this configuration, the magnetic flux density of the planar coil increases as it approaches the center of the spiral. Therefore, as the magnetic flux density becomes higher, the area ratio of the opening per unit area in the conductor portion becomes larger, and the space where eddy current can be generated on the conductor portion becomes smaller. As a result, the eddy current loop becomes smaller. As a result, the higher the magnetic flux density and the easier the eddy current is generated, the smaller the eddy current loop is, and the eddy current loss is reduced. A ratio becomes small and the reduction | decrease of the conductor cross-sectional area of the conductor part by an opening part is suppressed.

  As a result, at a location where the magnetic flux density is small, an increase in the DC resistance of the conductor portion due to the opening is suppressed, and the DC loss is reduced. This makes it possible to balance the reduction in eddy current loss and the increase in DC resistance so that the loss in the entire planar coil is minimized.

  Moreover, it is preferable that the size of each opening is increased as it approaches the center of the spiral.

  According to this configuration, by increasing the size of each opening closer to the center of the spiral, the area ratio of the plurality of openings per unit area in the conductor portion is increased toward the center of the spiral. Can do.

  Further, the plurality of openings may be provided so that the number of the plurality of openings per unit area in the conductor portion increases toward the center of the spiral.

  According to this configuration, the area ratio of the plurality of openings per unit area in the conductor portion is increased by increasing the number of the plurality of openings per unit area in the conductor portion toward the center of the spiral. The closer to the center of the spiral, the larger it can be. Also, in this configuration, it is easier to increase the number of openings than changing the area ratio of the openings per unit area by changing the size of the openings. As a result of facilitating scattering of the current flowing through the portion, it is easy to reduce the proximity effect.

  An electric apparatus according to the present invention includes the planar coil described above and a load circuit that is driven based on a voltage induced in the planar coil by electromagnetic induction.

  According to this configuration, an electric device including a load circuit that is driven based on a voltage induced in a planar coil by electromagnetic induction is thinned by using a planar coil that is thinner than a winding coil, and high-frequency loss is reduced. It becomes possible.

  A power supply device according to the present invention includes the above-described planar coil and a high-frequency current supply unit that supplies a high-frequency current to the planar coil.

  According to this configuration, it is possible to reduce the high-frequency loss while reducing the thickness of the power supply device that generates a high-frequency magnetic field by supplying a high-frequency current to the planar coil by using a planar coil that is thinner than the winding coil. Become.

  In addition, a non-contact power transmission system according to the present invention includes the above-described electrical device and a power supply device that is disposed to face a planar coil in the electrical device and induces a voltage in the planar coil by electromagnetic induction.

  According to this configuration, since high-frequency loss in the planar coil included in the electrical device is reduced, the efficiency of non-contact power transmission by electromagnetic induction from the power supply device is improved.

  Further, the power supply device is the above-described power supply device, and it is preferable that the electric device and the power supply device are arranged so that a planar coil in the electric device and a planar coil in the power supply device are opposed to each other. .

  According to this configuration, it is possible to reduce high-frequency loss while making the coil of the power supply device a thin planar coil, and it is easy to reduce the size of the power supply device.

  The planar coil having such a configuration can be thinned while reducing high-frequency loss. In addition, the electric device, the power supply device, and the non-contact power transmission system having such a configuration can be easily downsized by using such a planar coil.

  Embodiments according to the present invention will be described below with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted.

(First embodiment)
FIG. 1 is a block diagram showing an example of the configuration of an electric device, a power supply device, and a non-contact power transmission system using a planar coil according to the first embodiment of the present invention. A non-contact power transmission system 1 illustrated in FIG. 1 includes an electrical device 2 and a power supply device 3.

  The power supply device 3 is a power supply device that supplies power to the electrical equipment 2 in a contactless manner by electromagnetic induction. The power supply device 3 includes, for example, connection terminals 31 and 32, a DC power supply circuit 33, an inverter circuit 34 (high-frequency current supply unit), and a planar coil 30. For example, a commercial AC power supply 100 is connected to the connection terminals 31 and 32.

  The DC power supply circuit 33 is configured by, for example, a switching power supply circuit, converts the AC voltage received at the connection terminals 31 and 32 into a DC voltage, and supplies the DC voltage to the inverter circuit 34. The inverter circuit 34 chops the DC voltage output from the DC power supply circuit 33 to generate a high-frequency current, and supplies it to the planar coil 30. The planar coil 30 generates a high frequency magnetic field according to the high frequency current supplied from the inverter circuit 34.

  In addition, since the power supply device 3 is often connected to the commercial AC power supply 100 and used as a fixed facility, the need for downsizing is not as high as that of the electric device 2. Accordingly, a winding coil may be used instead of the planar coil 30, but the planar coil 30 can be easily manufactured by using an inexpensive manufacturing method such as pressing as described later. By using, it becomes easier to reduce the cost than the winding coil.

  The electric device 2 is a device that receives power supply from the power supply device 3 in a non-contact manner, such as a mobile phone or an electric shaver, and operates based on the power. The electric device 2 includes, for example, a planar coil 20, a charging circuit 21, a secondary battery 22, and a load circuit 23.

  By arranging the power supply device 3 and the electric device 2 to face each other, the planar coil 30 and the planar coil 20 are arranged so that the planar coil 30 and the planar coil 20 face each other in close proximity. . An induced voltage is generated in the planar coil 20 by electromagnetic induction caused by a high-frequency magnetic field generated by the planar coil 30.

  The charging circuit 21 includes, for example, a switching power supply circuit, a control circuit that performs charging control of the secondary battery 22, and the like. Then, the charging circuit 21 generates a charging current and voltage for the secondary battery 22 from the AC induced voltage generated in the planar coil 20, and charges the secondary battery 22. A load circuit 23 is connected to the secondary battery 22.

  The load circuit 23 is a load circuit that is driven by the electric power stored in the secondary battery 22 based on the induced voltage generated in the planar coil 20. The load circuit 23 may be, for example, a wireless circuit in a mobile phone, a liquid crystal display circuit, a digital camera, and a control circuit thereof, and may be, for example, a motor in an electric shaver or other various electric circuits. May be.

  FIG. 2 is a plan view showing an example of the configuration of the planar coils 20 and 30 shown in FIG. The planar coils 20 and 30 shown in FIG. 2 are configured by, for example, flat conductor portions 4 arranged in a spiral shape. Lead portions 5 and 6 are attached to the beginning and end of winding of the conductor portion 4. 2 shows an example in which the conductor part 4 is wound in a circular shape, but the present invention is not limited to a circular spiral, and may be a rectangular spiral such as a hexagon or a square.

  The conductor portion 4 is provided with a plurality of openings 7 along the longitudinal direction. The conductor part 4 and the opening part 7 are formed, for example, by stamping a metal plate, etching, or laser processing. In particular, if the planar coils 20 and 30 are formed by stamping with a press, it is easier to manufacture at a lower cost than a wound coil.

  For example, as shown in FIG. 3, the conductor portion 4, the opening portion 7, and the lead portion 6 are formed on the surface of the substrate 8 made of, for example, glass epoxy or polyimide by using a printed wiring board manufacturing process. Also good. Further, the winding start of the conductor portion 4 may be connected to an unillustrated lead portion formed on the back surface of the substrate 8 through the through hole 51.

  FIG. 4 is an enlarged view of the conductor portion 4 shown in FIG. As shown in FIG. 4, the opening 7 is formed in a circle having a diameter of about 10 to 50% with respect to the line width of the conductor 4, for example. The opening 7 is not limited to a circle, and for example, as shown in FIG. 5, one side may be a polygon such as a rectangle having a side width of about 10 to 50% with respect to the line width of the conductor 4. It may be a shape. Further, the direction in which the opening 7 such as a quadrangle is arranged with respect to the conductor 4 is not limited.

  FIG. 6 is a conceptual diagram for explaining the operation of the planar coil 20 shown in FIG. The planar coil 20 shown in FIG. 6 has shown the XX cross section of the planar coil 20 shown in FIG. A power supply device 3a shown in FIG. 6 shows an example in which a winding coil 30a is provided instead of the planar coil 30 in the power supply device 3 shown in FIG. As shown in FIG. 6, when the electric device 2 and the power supply device 3a are arranged to face each other, the planar coil 20 and the winding coil 30a are connected to the wall 25 of the casing of the electric device 2 and the casing of the power supply device 3a. The body wall 35 is placed opposite to the body wall 35.

  The planar coil 20 is covered with the magnetic layer 9, and an iron core 36 is fitted in the winding coil 30a. When a high frequency current flows through the winding coil 30a, the magnetic flux generated in the winding coil 30a flows through the iron core 36 and the magnetic layer 9, and an induced voltage is induced in the planar coil 20. Although the iron core 36 and the magnetic layer 9 are not necessarily required, the provision of the iron core 36 and the magnetic layer 9 enhances the magnetic coupling between the winding coil 30a and the planar coil 20, and the winding coil. The power transmission efficiency from 30a to the planar coil 20 is improved.

  As shown in FIG. 6, the planar coil 20 is thinner than the winding coil 30a. Thus, in the electric equipment 2, for example, the coil can be thinned by using the planar coil 20 as compared with the case where a winding coil using a litz wire is used, so that the electric equipment 2 can be thinned. Becomes easy.

  Moreover, since the opening part 7 is provided in the conductor part 4 of the planar coil 20 as shown in FIG.4 and FIG.5, the space which can produce an eddy current on the conductor part 4 becomes small, and the loop of an eddy current is produced. Get smaller. As a result, eddy current loss is reduced, and high-frequency loss in the planar coil 20 is reduced.

  Further, when a high-frequency current flows through the plate-like conductor, a proximity effect is generated in which an apparent AC resistance increases due to electromagnetic interaction between AC currents flowing in parallel. However, since the conductor portion 4 is provided with a plurality of openings 7 along the longitudinal direction of the conductor portion 4, that is, the direction of current flow, the direction of the current flowing through the plurality of openings 7 is scattered. The proximity effect is reduced and the high-frequency loss is reduced.

  For example, as shown in FIG. 7A, a plurality of rows, for example, two rows of the row of the opening 7 a and the row of the opening 7 b may be provided along the longitudinal direction of the conductor portion 4. Furthermore, it is preferable that the openings 7a and the openings 7b are arranged alternately. Further, as shown in FIG. 7B, for example, three rows of a row of openings 7a, a row of openings 7b, and a row of openings 7c are provided, and at least adjacent rows of the openings 7a, 7b, 7c are provided. You may arrange | position so that opening parts may become alternate. Moreover, as shown in FIG.7 (c), the opening part 7d may reach the side part of the conductor part 4, and the side part of the conductor part 4 may be parted.

  As described above, the plurality of openings 7 are alternately provided along the longitudinal direction of the conductor part 4, and as a result, the degree of current scattering is increased. As a result, the proximity effect is greater than when the openings 7 are not staggered. Is reduced, and high-frequency loss is reduced.

  As shown in FIGS. 8A, 8B, 8C, and 8D, the openings 7, 7a, 7b, 7c, and 7d are polygons such as a quadrangle. It may be any other shape. Further, the direction in which the opening 7 such as a quadrangle is arranged with respect to the conductor 4 is not limited.

(Second Embodiment)
Next, the electric equipment 2a, the power supply device 3a, and the non-contact power transmission system 1a using the planar coils 20a and 30b according to the second embodiment of the present invention will be described. The configuration of the electric device 2a, the power supply device 3a, and the non-contact power transmission system 1a according to the second embodiment of the present invention is shown in FIG.

  The non-contact power transmission system 1a shown in FIG. 1 is different from the non-contact power transmission system 1 in that an electric device 2a and a power supply device 3a are provided instead of the electric device 2 and the power supply device 3. Moreover, the electric device 2a shown in FIG. 1 is different from the electric device 2 in that a flat coil 20a is provided instead of the flat coil 20. 1 is different from the power supply device 3 in that a planar coil 30b is provided instead of the planar coil 30.

  Since the other configuration is the same as that of the non-contact power transmission system 1 shown in FIG. 1, the description thereof will be omitted, and the characteristic points of the present embodiment will be described below.

  9 and 10 are explanatory diagrams for explaining an example of the configuration of the planar coils 20a and 30a. 10A shows the opening 7 in the outer periphery of the planar coils 20a and 30a, FIG. 10B shows the opening 7 in the center of the planar coils 20a and 30a, and FIG. 10C shows the planar coil. The opening part 7 in the inner peripheral part of 20a, 30a is shown.

  The size of the opening 7 is increased as it approaches the center of the planar coils 20a, 30a, and the area ratio of the opening 7 per unit area in the conductor 4 is increased as it approaches the center of the spiral. Has been. For example, in the outer periphery of the planar coils 20a and 30a, the area ratio of the opening 7 is set to 0% or more and less than 30% (FIG. 10A), and the outer periphery of the planar coils 20a and 30a includes an opening. 7 is not necessarily provided. Further, the area ratio of the opening 7 is set to 30% or more and less than 50% at the center of the planar coils 20a and 30a (FIG. 10B), and the opening is formed at the inner periphery of the planar coils 20a and 30a. The area ratio of 7 is 50% or more and less than 70% (FIG. 10C).

  The planar coils 20a and 30a have higher magnetic flux density as they approach the center of the spiral. Therefore, as the magnetic flux density becomes higher, the area ratio of the opening 7 per unit area in the conductor 4 becomes larger, and the space where eddy current can be generated on the conductor 4 becomes smaller. As a result, the eddy current loop becomes smaller. Become. As a result, the portion where the magnetic flux density is high and the eddy current is easily generated reduces the eddy current loss by reducing the eddy current loop, while the portion where the magnetic flux density is low and the eddy current is difficult to generate is An area ratio becomes small and the reduction | decrease of the conductor cross-sectional area of the conductor part 4 by the opening part 7 is suppressed.

  As a result, at a location where the magnetic flux density is small, an increase in the DC resistance of the conductor portion 4 by the opening 7 is suppressed, and the DC loss is reduced. This makes it possible to balance the reduction in eddy current loss and the increase in DC resistance so that the loss in the entire planar coils 20a and 30a is minimized.

  For example, as shown in FIG. 11, without changing the size of the opening 7, for example, the outer periphery of the planar coils 20a and 30a is FIG. 11 (a), and the central portion of the planar coils 20a and 30a is FIG. ) In the inner peripheral portions of the planar coils 20a and 30a, as shown in FIG. 11C, the opening portions are formed so that the number of the opening portions 7 per unit area in the conductor portion 4 increases as the spiral center is approached. By providing 7, the area ratio of the opening 7 per unit area in the conductor part 4 may be increased as it approaches the center of the spiral.

  As a result, the portion where the magnetic flux density is high and the eddy current is easily generated reduces the eddy current loss by reducing the eddy current loop, while the portion where the magnetic flux density is low and the eddy current is difficult to generate is An area ratio becomes small and the reduction | decrease of the conductor cross-sectional area of the conductor part 4 by the opening part 7 is suppressed.

  As a result, at a location where the magnetic flux density is small, an increase in the DC resistance of the conductor portion 4 by the opening 7 is suppressed, and the DC loss is reduced. This makes it possible to balance the reduction in eddy current loss and the increase in DC resistance so that the loss in the entire planar coils 20a and 30a is minimized.

  Furthermore, since it is easier to increase the number of openings 7 than to change the area ratio of the openings 7 per unit area by changing the size of the openings 7, the number of openings 7 can be increased to increase the number of conductors. As a result of facilitating scattering of the current flowing through the portion 4, it becomes easy to reduce the proximity effect.

  10 and 11, the opening 7 may be a polygon such as a quadrangle or other shapes. Further, the direction in which the opening 7 such as a quadrangle is arranged with respect to the conductor 4 is not limited.

It is a block diagram which shows an example of a structure of the electric equipment using the planar coil which concerns on 1st Embodiment of this invention, an electric power supply apparatus, and a non-contact electric power transmission system. It is a top view which shows an example of a structure of the planar coil shown in FIG. It is a top view which shows the modification of the planar coil shown in FIG. It is an enlarged view of the conductor part shown in FIG. It is an enlarged view which shows the modification of the opening part shown in FIG. It is a conceptual diagram for demonstrating operation | movement of the planar coil shown in FIG. It is an enlarged view which shows the other modification of the opening part shown in FIG. It is an enlarged view which shows the other modification of the opening part shown in FIG. It is explanatory drawing for demonstrating an example of a structure of the planar coil which concerns on 2nd Embodiment of this invention. It is an enlarged view of the conductor part of the planar coil shown in FIG. (A) shows the opening in the outer periphery of the planar coil, (b) shows the opening in the center of the planar coil, and (c) shows the opening in the inner periphery of the planar coil. It is an enlarged view which shows the modification of the opening part shown in FIG. (A) shows the opening in the outer periphery of the planar coil, (b) shows the opening in the center of the planar coil, and (c) shows the opening in the inner periphery of the planar coil.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1a Non-contact electric power transmission system 2,2a Electric equipment 3,3a Power supply device 4 Conductor part 7,7a, 7b, 7c, 7d Opening part 8 Board | substrate 9 Magnetic body layer 20, 20a Planar coil 21 Charging circuit 22 Secondary Battery 23 Load circuit 30, 30b Planar coil 30a Winding coil 33 DC power supply circuit 34 Inverter circuit 36 Iron core

Claims (9)

A planar coil in which flat conductor portions are arranged in a spiral shape,
A planar coil comprising a plurality of openings along the longitudinal direction of the conductor. The plurality of openings are provided in a plurality of rows extending in the longitudinal direction of the conductor portion,
The planar coil according to claim 1, wherein openings in adjacent rows of the plurality of rows are alternately arranged. The plurality of openings are provided such that an area ratio of the plurality of openings per unit area in the conductor portion increases as the area approaches the center of the spiral. The described planar coil. The planar coil according to claim 3, wherein the size of each of the openings is increased toward the center of the spiral. 4. The plane according to claim 3, wherein the plurality of openings are provided so that the number of the plurality of openings per unit area in the conductor portion increases toward the center of the spiral. coil. A planar coil according to any one of claims 1 to 5,
An electric device comprising: a load circuit driven based on a voltage induced in the planar coil by electromagnetic induction. A planar coil according to any one of claims 1 to 5,
A power supply device comprising: a high-frequency current supply unit that supplies a high-frequency current to the planar coil. An electrical device according to claim 6;
A non-contact power transmission system comprising: a power supply device arranged to face a planar coil in the electric device and inducing a voltage in the planar coil by electromagnetic induction. The power supply device is the power supply device according to claim 7,
The non-contact power transmission system according to claim 8, wherein the electrical device and the power supply device are configured such that a planar coil in the electrical device and a planar coil in the power supply device are opposed to each other.

Images