JP2020061502A - Power transmission coil and wireless power supply device - Google Patents

Abstract

To provide a power transmission coil and a wireless power supply device capable of suppressing an adverse effect of a current flowing through a straight line portion on a magnetic field in a region contributing to power feeding when a coil path has adjacent straight line portions.SOLUTION: A power transmission coil 110 includes a first section 111 having a linear route 111d, and a second section 112 having a linear route 112d. The route of the first section 111 and the route of the second section 112 are connected to each other. The first section 111 and the second section 112 are adjacent to each other with a gap in between. The route 111d and the route 112d face each other with a gap in between. The direction of the current flowing through the route 111d and the direction of the current flowing through the route 112d are the same.SELECTED DRAWING: Figure 3

Description

  The technical field of the present specification relates to a power transmission coil and a wireless power supply device.

  2. Description of the Related Art In recent years, technologies for wirelessly feeding power to mobile communication terminals such as smartphones and other electronic devices have been actively researched and developed. In addition, a technique for wirelessly feeding electric power to electronic devices for vehicles has been developed.

  As a coil used for wireless power feeding, a coil wound in a figure 8 shape may be used. For example, Patent Document 1 discloses a power feeding coil 11a and a power receiving coil 21a that are wound a plurality of times in a figure 8 shape (see FIG. 3 and the like of Patent Document 1). It is disclosed that the two coil portions mutually absorb the lines of magnetic force by making the currents flowing through the two adjacent coil portions in the shape of figure 8 in opposite directions (paragraph [0043] of Patent Document 1). . Further, it is disclosed that unnecessary electromagnetic field radiation can be suppressed from leaking around the power feeding coil 11a and the power receiving coil 21a (paragraph [0046] of Patent Document 1).

  Further, Patent Document 2 discloses an antenna having loop coils 43A and 43B wound once in a figure 8 shape (see FIG. 1 and the like of Patent Document 2). It is disclosed that the magnetic flux 45 generated from one loop coil 43A enters the other adjacent loop coil 43B and the magnetic flux 45 is closed (paragraph [0035] of Patent Document 2). As a result, it is disclosed that the magnetic flux density is high.

JP, 2013-247822, A Japanese Patent Laid-Open No. 08-330838

  However, depending on the location of the power transmission coil, it may be necessary to make the coil shape to have a linear portion instead of an arc. In this case, the current flowing through the straight line portion may adversely affect the magnetic field around the power transmission coil. In particular, when the straight line portions are adjacent to each other, the current flowing through the straight line portions may have a relatively large effect on the magnetic field in the region that contributes to power feeding. In this case, noise may occur in the current flowing through the power receiving coil.

  A problem to be solved by the technique of the present specification is, when a coil path has adjacent straight line portions, it is possible to suppress an adverse effect of a current flowing through the straight line portions on a magnetic field in a region contributing to power feeding. And to provide a wireless power feeding device.

  The power transmission coil in the first aspect has a first section having a first path including a straight line portion and a second section having a second path including a straight line portion. The route of the first section and the route of the second section are connected. The first section and the second section are adjacent to each other with a gap in between. The first path and the second path face each other with a gap in between. The angle formed by the direction of the current flowing through the straight line portion of the first path and the direction of the current flowing through the straight line portion of the second path is 0 ° or more and 10 ° or less.

  This power transmission coil can suppress the adverse effect of the current flowing in the straight line portion on the magnetic field in the region that contributes to power supply, when the coil paths have adjacent straight line portions. That is, it is possible to cause almost no noise during power feeding. Further, because of the straight line portion, the power transmission coil may be easily arranged.

  The present specification provides a power transmission coil and a wireless power feeding device that can suppress an adverse effect that a current flowing in a linear portion has on a magnetic field in a region that contributes to power feeding when the coil path has adjacent linear portions. There is.

It is a figure which shows the shape of the power transmission coil of 1st Embodiment. It is a figure explaining the case where current is flowing through the power transmission coil of 1st Embodiment. It is a figure explaining the magnetic field which the electric current which flows into the power transmission coil of 1st Embodiment forms. It is an enlarged view of the connection part of the power transmission coil of 1st Embodiment. It is an enlarged view of the connection part of the power transmission coil in the modification of 1st Embodiment. It is a schematic diagram which shows the appearance inside the vehicle in 2nd Embodiment. It is a schematic diagram which shows schematic structure of the wireless power feeder of 2nd Embodiment. It is a figure which shows typically the circuit of the wireless power feeder of 2nd Embodiment.

  Hereinafter, specific embodiments will be described by taking a power transmission coil and a wireless power supply device as examples. However, the technology of the present specification is not limited to these embodiments.

(First embodiment)
1. Power Transmission Coil FIG. 1 is a diagram showing the shape of the power transmission coil 110 of the present embodiment. In FIG. 1, the number of turns of the power transmission coil 110 is three. The material of the power transmission coil 110 is a metal wire rod. Examples of the wire material include a single wire and a litz wire.

  The power transmission coil 110 has two sections that surround the two regions. The power transmission coil 110 has a first section 111, a second section 112, a connecting section 113, an end section 114, and an end section 115. As is apparent from FIG. 1, the connected wire rods are classified into a first section 111, a second section 112, a connecting section 113, an end section 114, and an end section 115. The first section 111 and the second section 112 are substantially on the same plane.

1-1. 1st division and 2nd division The 1st division 111 and the 2nd division 112 each transmit to another receiving coil. The first section 111 transmits power to the first power receiving coil, and the second section 112 transmits power to the second power receiving coil. In this way, the power transmission coil 110 can transmit power to the two power receiving coils.

  The first section 111 has four paths 111a, 111b, 111c, 111d. The four routes 111a, 111b, 111c, 111d are routes including straight line portions. Each of the four paths 111a, 111b, 111c, and 111d generates a magnetic field near the center of the first section 111. Thus, since the four paths 111a, 111b, 111c, 111d surround the first region R1, a relatively strong magnetic field is formed around the first region R1.

  The second section 112 has four paths 112a, 112b, 112c, 112d. The four routes 112a, 112b, 112c, 112d are routes including straight line portions. Each of the four paths 112a, 112b, 112c, 112d generates a magnetic field near the center of the second section 112. In this way, since the four paths 112a, 112b, 112c, 112d surround the second region R2, a relatively strong magnetic field is formed around the second region R2.

  The route 111d is a first route including a straight line portion. The route 112d is a second route including a straight line portion. The path 111d and the path 112d face each other with a gap in between. Further, as described above, the path of the first section 111, the path of the second section 112, and the path of the connecting portion 113 are connected. The first section 111 and the second section 112 are adjacent to each other with a gap in between.

1-2. Connecting part The connecting part 113 connects the first section 111 and the second section 112. The length of the connecting portion 113 is sufficiently shorter than the paths 111a, 111b, 111c, 111d and the paths 112a, 112b, 112c, 112d.

1-3. 1st area | region, 2nd area | region, and 3rd area | region 1st area | region R1 is an area | region enclosed by the path | routes 111a, 111b, 111c, 111d of the 1st division 111. The second region R2 is a region surrounded by the paths 112a, 112b, 112c, 112d of the second section 112. The third region R3 is a region located between the first section 111 and the second section 112 and not surrounded by the route. The third region R3 is a gap between the first section 111 and the second section 112. Therefore, the width of the third region R3 is narrower than the width of the first region R1 and the width of the second region R2.

1-4. Size of Power Transmission Coil Assuming that the surface surrounded by one turn of the power transmission coil 110 is the xy plane, the power transmission coils 110 are stacked in the z-axis direction perpendicular to the xy plane.

  The horizontal axis direction of FIG. 1 is virtually set as the x-axis direction. The length of the power transmission coil 110 in the x-axis direction is, for example, 10 mm or more and 400 mm or less. It may be 80 mm or more and 350 mm or less. The length of the power transmission coil 110 in the y-axis direction is, for example, 10 mm or more and 400 mm or less. It is good that it is 50 mm or more and 100 mm or less. The length of the power transmission coil 110 in the z-axis direction is, for example, 0.5 mm or more and 10 mm or less. The length of the connecting portion 113, that is, the distance between the route 111d and the route 112d is, for example, 20 mm or more and 50 mm or less. These numerical ranges are for reference, and other numerical values may be used.

2. Current and magnetic field flowing in power transmission coil 2-1. Current FIG. 2 is a diagram illustrating a case where a current is flowing in the power transmission coil 110 of the present embodiment. An alternating current flows through the power transmission coil 110. In FIG. 2, the direction in which the current is flowing at a certain time is indicated by an arrow.

  As shown in FIG. 2, in this case, the current flows through the end portion 114, the route 111a, the connecting portion 113, the route 112d, the route 112c, the route 112b, the route 112a, the connecting portion 113, the route 111d, the route 111c, and the route 111b. , In that order, and reaches the end 115.

  In the adjacent paths in the connecting portion 113, currents flow in opposite directions.

2-2. Magnetic Field In the first region R1, currents flowing in the path 111a, the path 111b, the path 111c, and the path 111d form a magnetic field. This magnetic field strengthens each other. In the first region R1, the magnetic field is formed in the + z-axis direction from the back of the paper to the front.

  In the second region R2, the current flowing through the path 112a, the path 112b, the path 112c, and the path 112d forms a magnetic field. This magnetic field strengthens each other. In the second region R2, the magnetic field is formed in the −z-axis direction from the front side to the back side of the paper.

  At this time, currents flow in the same direction on the facing paths 111d and 112d. Then, in the third region R3 between the path 111d and the path 112d, the first magnetic field formed by the current flowing through the path 111d and the second magnetic field formed by the current flowing through the path 112d cancel each other out. . That is, the magnetic fields do not reinforce each other in the third region R3.

  In reality, the current flowing through the power transmission coil 110 is alternating current. Even considering that it is an alternating current, in the first region R1 of the first section 111, the magnetic fields are mutually strengthened in the first direction, and in the second region R2 of the second section 112, the magnetic field is generated in the second direction. Strengthen each other. Here, the first direction and the second direction are opposite directions. In this way, the direction of the magnetic field of the first region R1 and the direction of the magnetic field of the second region R2 are opposite. On the other hand, in the third region located between the first region R1 and the second region R2, the magnetic fields weaken each other.

3. Effect of this Embodiment FIG. 3 is a schematic diagram illustrating a magnetic field formed by a current flowing through the power transmission coil 110 of this embodiment. As shown in FIG. 3, a magnetic field connecting the first region R1 and the second region R2 is formed. The flow of the magnetic field is shown by an arrow L1 in FIG. In this way, the magnetic field of the first region R1 and the magnetic field of the second region R2 reinforce each other. Further, the magnetic flux penetrates and closes the first region R1 and the second region R2.

  Since the third region R1 that weakens the magnetic field is located between the first region R1 and the second region R2, the magnetic fields of the first region R1 and the second region R2 are It is hardly affected by the magnetic field in the region R3. Due to the alternating current, the magnetic fields of the first region R1 and the second region R2 greatly fluctuate, but the magnetic field of the third region R3 remains small. Therefore, the third region R3 serves as a buffer region for the first region R1 and the second region R2.

  As described above, the magnetic field formed by the power transmission coil 110 is stable. Therefore, when a current is passed through the power transmission coil 110, high frequency noise or the like is unlikely to occur.

  Since the connecting portion 113 is apart from the first region R1 and the second region R2 to some extent, a current flowing through the path of the connecting portion 113 is formed in the first region R1 and the second region R2. It is considered that it has almost no effect on the magnetic field.

4. Modification 4-1. Angle of the straight path facing each other In the present embodiment, the direction of the current flowing through the path 111d and the direction of the current flowing through the path 112d are the same. However, the route 111d and the route 112d may not be parallel to each other. Even in that case, the angle formed by the direction of the current flowing through the path 111d and the direction of the current flowing through the path 112d may be small. The angle formed by the direction of the current flowing through the path 111d and the direction of the current flowing through the path 112d is preferably 0 ° or more and 10 ° or less. Further, it is more preferable that this angle is 0 ° or more and 5 ° or less. It is 0 ° when the direction of the current flowing through the path 111d and the direction of the current flowing through the path 112d are the same. When these directions are opposite, it is 180 °.

4-2. Stacking Method FIG. 4 is an enlarged view of the connecting portion 113 of the power transmission coil 110 of this embodiment. As shown in FIG. 4, in adjacent wire materials, currents flow in opposite directions. That is, in the connecting portion 113, the paths through which the current flows from the first section 111 to the second section 112 and the paths through which the current flows from the second section 112 to the first section 111 are arranged alternately.

  FIG. 5 is an enlarged view of the connecting portion 113 of the power transmission coil 110 according to the modified example of the present embodiment. As shown in FIG. 5, current flows in the same direction in adjacent wire rods belonging to the same bundle. However, in the connecting portion 113, the currents flow in opposite directions in the wire rods belonging to different bundles. That is, the coupling unit 113 collects the first bundle B1 in which the current flows from the first section 111 to the second section 112 and the second bundle B1 in which the current flows from the second section 112 to the first section 111. And a bundle B2 of.

4-3. Curved portion The path of the power transmission coil 110 may have a curved portion. For example, the portions corresponding to the route 111a and the route 112a may have a curved shape. Of course, the portion corresponding to the other path may have a curved shape. However, as described in the second embodiment, in consideration of the arrangement of the power transmission coil 110, it may be preferable that each path be linear.

  The paths corresponding to the paths 111d and 112d may include a curved shape. Even in that case, the routes corresponding to the routes 111d and 112d include at least a straight line portion. The angle formed by the straight line portions of the respective paths is preferably 0 ° or more and 10 ° or less.

4-4. Combination The above modifications may be freely combined.

(Second embodiment)
The second embodiment will be described. In the second embodiment, a wireless power supply device suitable for adopting the power transmission coil 110 of the first embodiment will be described.

1. In-Vehicle Parts FIG. 6 is a schematic diagram showing the inside of the vehicle. As shown in FIG. 6, there is an instrument panel IP in front of the driver's seat of the vehicle. The instrument panel IP is provided with a plurality of air conditioning registers CA1. The air-conditioning register CA1 has a housing 160 and a knob N1 for the user to adjust the wind direction. The knob N1 is capable of emitting light. This is because the user can easily grasp the position of the knob N1 even when the inside of the vehicle is dark.

2. Wireless Power Supply Device FIG. 7 is a schematic diagram showing a schematic configuration of the wireless power supply device 100 of the first embodiment. The wireless power supply apparatus 100 performs magnetic field coupling type wireless power supply. As illustrated in FIG. 7, the wireless power supply apparatus 100 includes one power transmitting coil 110, two power receiving coils 120, a power transmitting circuit 130, a power receiving circuit 140, a light emitting device 150, and a housing 160. Have.

  The resonance frequency of the wireless power feeding apparatus 100 is 6.78 MHz. Therefore, the frequency of the current flowing through the power transmitting coil 110 and the power receiving coil 120 is 6.78 MHz. The resonance frequency of the LC circuit of the power transmission coil 110 is also 6.78 MHz. The resonance frequency of the LC circuit of the power receiving coil 120 is also 6.78 MHz. The frequency of the current passed by the power transmission circuit 130 to the power transmission coil 110 is also 6.78 MHz. In reality, it may be slightly off the target frequency. Moreover, although 6.78 MHz is mentioned as an example, for example, a resonance frequency of 500 kHz or more and 15 MHz or less may be adopted. In addition, resonance frequencies other than the above may be used.

  The power transmission coil 110 is a coil for forming a magnetic field around the power reception coil 120. The power transmission coil 110 is connected in series with a capacitor described later. The power transmission coil 110 is made of a wire rod. Examples of the wire material include a single wire and a litz wire. The material of the power transmission coil 110 is, for example, copper. The power transmission coil 110 has a shape surrounding two quadrilaterals. The power transmission coil 110 is an air core. The number of turns of the power transmission coil 110 may be 1 or more and 3 or less. Of course, it is not limited to this numerical range. In addition, in FIG. 7, the number of turns of the power transmission coil 110 is one. The power transmission coil 110 is fitted in, for example, a groove of the housing 160.

  The power receiving coil 120 is a coil that generates a current by the magnetic field formed by the power transmitting coil 110. The power receiving coil 120 is connected in series with a capacitor described later. The power receiving coil 120 is made of a wire rod. Examples of the wire material include a single wire and a litz wire. The material of the power receiving coil 120 is, for example, copper. In FIG. 7, the power receiving coil 120 has a shape close to a quadrangle, but may have a spiral shape like a spring.

  The power transmission circuit 130 is a circuit for oscillating an AC voltage flowing through the power transmission coil 110. The power transmission circuit 130 generates an alternating current of 6.78 MHz.

  The power receiving circuit 140 is a circuit for converting a current flowing through the power receiving coil 120 into a current suitable for the light emitting device 150. Specifically, the AC voltage of the power receiving coil 120 is converted into a DC voltage for driving the light emitting device 150. The power receiving circuit 140 may have other functions such as a rectifying circuit.

  The light emitting device 150 is for indicating the position of the knob N1 so that the user can easily understand the position even in a dark vehicle. The light emitting device 150 is an electronic component driven by electric power from the power receiving coil 120. The light emitting device 150 constitutes a part of the knob N1 of the air conditioning register. The light emitting device 150 has a semiconductor light emitting element. The light emitting device 150 emits light by a DC voltage. The light emitting device 150 is an electronic device and an electronic component. The knob N1 is an operation unit operated by the user. The user can adjust the wind direction of the air conditioning register CA1 by changing the position of the knob N1.

  The housing 160 is a housing of the air conditioning register CA1. That is, the device surrounded by the housing 160 is the air conditioning register CA1. The material of the housing 160 is, for example, plastic. The housing 160 is a housing of the apparatus, and thus its thickness is sufficiently thin.

3. Circuit of Wireless Power Supply Device FIG. 8 is a diagram schematically showing a circuit of the wireless power supply device 100 of the present embodiment. As shown in FIG. 8, the power transmission coil 110 constitutes an LC series circuit together with the capacitor C1. The power receiving coil 120 constitutes an LC series circuit together with the capacitor C2. As described above, the circuit is designed so that the resonance frequency of the LC series circuit on the power transmission coil 110 side and the resonance frequency of the LC series circuit on the power reception coil 120 side are equal.

  The power transmission output of the wireless power supply apparatus 100 is 10 W or less. For example, it is 5W. The voltage for driving the light emitting device 150 is, for example, 5V. Of course, a numerical value other than the above may be used. The current flowing through the light emitting device 150 is 1 mA or less. Of course, a numerical value other than the above may be used.

  Note that in FIG. 8, the capacitor C1 is depicted as being outside the power transmission circuit 130. FIG. 8 is conceptual, and the capacitor C1 may be included in the power transmission circuit 130. Similarly, the capacitor C2 may be included in the power receiving circuit 140.

4. Effect of the present embodiment In the present embodiment, the first section 111 and the second section 112 of the power transmission coil 110 respectively surround the housing 160. The shapes of the first section 111 and the second section 112 correspond to the housing 160. Therefore, the power transmission coil 110 can be easily attached to the housing 160. Then, even in a place where it is difficult to connect the wiring like the knob N1 of the air-conditioning register CA1, wireless power supply can be performed. In this way, flexibility in the design of vehicle components is improved.

  Further, vibration is generally generated in the vehicle. Therefore, the position of the power transmission coil 110, which should have been fixed, may be displaced. In the wireless power supply apparatus 100 according to the present embodiment, the power transmission coil 110 is sufficiently fixed to the housing 160, so that even if vibration repeatedly occurs in the vehicle, the position of the power transmission coil 110 is hardly displaced.

5. Modification 5-1. Support Member The support member provided in the housing 160 may have another shape or structure. For example, clips, spacers, etc. can be adopted.

5-2. Wireless power feeding method The wireless power feeding apparatus 100 of the present embodiment is a magnetic field coupling method. However, the technique of the first embodiment can also be applied to an electromagnetic induction type wireless power supply apparatus.

5-3. Housing The housing 160 of the present embodiment is a housing for an air conditioning register. However, the housing 160 may be a housing for other in-vehicle components. Further, it may be an electric appliance other than the in-vehicle component. The material of the housing 160 may be glass, resin, ceramics, or other non-conductive material.

5-4. Electronic Component The wireless power supply apparatus 100 of this embodiment includes the light emitting device 150. The wireless power supply apparatus 100 may include another electronic device or electronic component instead of the light emitting device 150.

5-5. Combination The above modifications may be freely combined.

(Appendix)
The power transmission coil in the first aspect has a first section having a first path including a straight line portion and a second section having a second path including a straight line portion. The route of the first section and the route of the second section are connected. The first section and the second section are adjacent to each other with a gap in between. The first path and the second path face each other with a gap in between. The angle formed by the direction of the current flowing through the straight line portion of the first path and the direction of the current flowing through the straight line portion of the second path is 0 ° or more and 10 ° or less.

  The power transmission coil in the second aspect includes a first region surrounded by the route of the first section, a second region surrounded by the route of the second section, a first region and a second region. A third region located between and not surrounded by the path. The direction of the magnetic field in the first region and the direction of the magnetic field in the second region are opposite. In the third region, the magnetic field formed by the current flowing through the first path and the magnetic field formed by the current flowing through the second path cancel each other out.

  The power transmission coil in the third aspect has a connecting portion that connects the first section and the second section. In the connecting portion, a path through which current flows from the first section to the second section and a path through which current flows from the second section to the first section are arranged alternately.

  The power transmission coil in the fourth aspect has a connecting portion that connects the first section and the second section. In the connecting portion, a first bundle that summarizes the paths through which the current flows from the first section to the second section and a second bundle that summarizes the paths through which the current flows from the second section to the first section are arranged. There is.

  In the power transmission coil according to the fifth aspect, the route of the first section and the route of the second section are wires.

  The wireless power supply apparatus according to the sixth aspect has a power transmitting coil and a power receiving coil. The power transmission coil has a first section having a first path including a straight line portion and a second section having a second path including a straight line section. The route of the first section and the route of the second section are connected. The first section and the second section are adjacent to each other with a gap in between. The first path and the second path face each other with a gap in between. The angle formed by the direction of the current flowing through the straight line portion of the first path and the direction of the current flowing through the straight line portion of the second path is 0 ° or more and 10 ° or less.

100 ... Wireless power supply device 110 ... Power transmission coil 111 ... First section 111a, 111b, 111c, 111d ... Path 112 ... Second section 112a, 112b, 112c, 112d ... Path 112 ... Connection part 120 ... Power receiving coil 130 ... Power transmission circuit 140 Power receiving circuit 150 Light emitting device 160 Housing R1 First region R2 Second region R3 Third region

Claims (6)

A first section having a first path including a straight line portion;
A second section having a second path including a straight line portion;
Have
The path of the first section and the path of the second section are connected,
The first section and the second section are adjacent to each other with a gap in between,
The first path and the second path face each other with the gap therebetween,
The angle formed by the direction of the current flowing through the straight line portion of the first path and the direction of the current flowing through the straight line portion of the second path is
A power transmission coil, which is 0 ° or more and 10 ° or less. The power transmission coil according to claim 1,
A first region surrounded by the path of the first section,
A second region surrounded by the path of the second section,
A third region located between the first region and the second region and not surrounded by a path;
Have
The direction of the magnetic field of the first region and the direction of the magnetic field of the second region are opposite,
In the third area,
A power transmission coil, wherein a magnetic field formed by a current flowing through the first path and a magnetic field formed by a current flowing through the second path cancel each other. The power transmission coil according to claim 1 or 2,
A connecting portion that connects the first section and the second section,
In the connection part,
A path through which current flows from the first section to the second section;
A path through which current flows from the second section to the first section;
A power transmission coil, wherein the coils are arranged alternately. The power transmission coil according to claim 1 or 2,
A connecting portion that connects the first section and the second section,
In the connection part,
A first bundle that summarizes paths through which current flows from the first section to the second section;
A second bundle that summarizes the paths through which current flows from the second compartment to the first compartment;
The power transmission coil is characterized by being arranged. The power transmission coil according to any one of claims 1 to 4,
The path of the first section and the path of the second section are
A power transmission coil, which is a wire rod. In a wireless power supply device having a power transmitting coil and a power receiving coil,
The power transmission coil is
A first section having a first path including a straight line portion;
A second section having a second path including a straight line portion;
Have
The path of the first section and the path of the second section are connected,
The first section and the second section are adjacent to each other with a gap in between,
The first path and the second path face each other with the gap therebetween,
The angle formed by the direction of the current flowing through the straight line portion of the first path and the direction of the current flowing through the straight line portion of the second path is
A wireless power supply device, which is 0 ° or more and 10 ° or less.

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