WO2013150784A1

WO2013150784A1 - Coil unit, and power transmission device equipped with coil unit

Info

Publication number: WO2013150784A1
Application number: PCT/JP2013/002293
Authority: WO
Inventors: 湯浅　安仁; 太志出口; 立松　英樹; 克也岡本; 江口　和弘
Original assignee: パナソニック株式会社
Priority date: 2012-04-02
Filing date: 2013-04-02
Publication date: 2013-10-10
Also published as: JP2013214613A

Abstract

Provided is a coil unit with which the proximity effect between lines is suppressed and resistance loss is inhibited, with which magnetic flux directivity is improved and coil inductance is increased, and with which coil Q value is increased. A coil unit (100) is provided with: a planar spirally wound coil (111) in which a magnetic material (120) is provided between the lines of a linear conductor (110); and a magnetic material sheet (130) which covers a surface of the planar spirally wound coil (111), said surface being opposite to a power transmission/receiving surface of the planar spirally wound coil (111). If the greatest cross-sectional length of the linear conductor (110) is Wc, and the width of the magnetic material (120) between the lines is Wg, then 0.2 ≤ Wg/Wc ≤ 3.5. Moreover, the magnetic permeability of the magnetic material (120) between the lines is in the range of 1000-3000[H/m] inclusive, and the magnetic permeability of the magnetic material sheet (130) is in the range of 50-500[H/m] inclusive.

Description

Coil unit and power transmission device including coil unit

The present invention relates to a coil unit and a power transmission device including the coil unit, for example, a coil unit and a power transmission device that transmit power in a non-contact manner by electromagnetic induction from a power transmission device to an electronic device or the like.

Conventionally, as a wireless power transmission device, electromagnetic induction between both coils between a primary-side power transmission coil provided on a power transmission device and a secondary-side power reception coil provided on an electronic device on the power reception side or the vehicle side There is a wireless power transmission device that performs power transmission using an action. In wireless power transmission, there is no exposure of the contact part, so it is easy to ensure waterproofness, and there is no need to worry about defects or deterioration of the electrical contact part, and it is easy to attach and detach the power transmission device and power receiving device There are advantages such as being able to do.

The primary side power transmission coil and the secondary side power reception coil that are mounted on these electronic devices or the like are generally used that are wound around a core or wound around a bobbin. In recent years, portable electronic devices on the power receiving side are required to be downsized, thinned, and highly functional. In response to these demands, it has been proposed to use a planar coil as a power transmission / reception coil provided in a power transmission device and a power receiving electronic device.

The wireless power transmission device includes a primary power transmission coil and a secondary power reception coil facing each other so that electromagnetic induction coupling can be made efficient. By converting the voltage from the commercial power source into a high-frequency AC voltage by a high-frequency inverter circuit and applying it to the primary-side power transmission coil, a high-frequency AC magnetic flux of 60 to 600 kHz is generated in the primary-side power transmission coil. Then, after the AC voltage induced by the AC magnetic flux in the secondary power receiving coil in the power receiving side electronic device is converted into DC by the secondary side rectifying and smoothing circuit by the electromagnetic induction action, the charging means 2 Power is supplied to the secondary battery.

A coil used as a power transmission / reception coil is reduced in size and thickness by using a planar coil formed in a spiral plane to reduce the size of the wireless power transmission device. However, since the core cannot be used when it is planarized, it is necessary to suppress unnecessary radiation due to the magnetic field generated from the coil and to improve the efficiency of power transmission.

In Patent Document 1, in order to increase the efficiency of power transmission, the primary side power transmission planar coil and the secondary side power reception planar coil are each provided with a magnetic sheet on the surface opposite to the surface where both faces each other. Are listed.

The wireless power transmission device described in Patent Document 1 uses a miniaturized coil at a high frequency of about 60 to 600 kHz in order to reduce the size of the device. The primary-side power transmission planar coil and the secondary-side power reception planar coil are each provided with a magnetic sheet on the surface opposite to the surface where both faces. Thereby, unnecessary radiation due to the magnetic field generated from the coil can be suppressed.

JP 2006-42519 A

However, since the power transmission device described in Patent Document 1 simply disposes the magnetic sheet, the proximity effect between the coil wires cannot be sufficiently suppressed. Further, the power transmission device described in Patent Literature 1 increases the generated magnetic flux intensity to suppress the decrease in wireless power transmission efficiency, and the generated magnetic flux further strengthens electromagnetic coupling with the secondary coil on the power receiving side. I can't do enough.

An object of the present invention is to provide a coil unit and a coil capable of suppressing the proximity effect between the lines and suppressing the resistance loss, increasing the directivity of the magnetic flux, increasing the inductance of the coil, and increasing the Q value of the coil. It is to provide a power transmission device including a unit.

A coil unit according to the present invention includes a planar coil formed by winding a linear conductor in a spiral shape, a first magnetic body interposed between lines of the linear conductor, and one side of the planar coil. And a second magnetic body provided so as to cover the surface.

A power transmission device according to the present invention is configured using the coil unit, and a power transmission coil in which a surface of the planar coil opposite to the surface facing the second magnetic body is disposed on a surface on the power transmission side. And a power transmission unit that supplies power to the power transmission coil.

A power transmission device according to the present invention is configured using the coil unit, and a power receiving coil in which a surface opposite to a surface facing the second magnetic body of the planar coil is disposed on a power receiving side surface; And a power receiving device that outputs the power received by the power receiving coil.

According to the present invention, it is possible to suppress the proximity effect between the lines and suppress the resistance loss, increase the directivity of the magnetic flux, increase the inductance of the coil, and increase the Q value of the coil. In addition, it is possible to suppress a decrease in power transmission efficiency and realize long-distance power transmission between the power transmission side and power reception side coils with high efficiency. Furthermore, even if there is a slight misalignment between the power transmission side and power reception side coils, it is possible to provide a power transmission device in which the power transmission efficiency is not greatly reduced.

The perspective view which shows the structure of the coil unit which concerns on Embodiment 1 of this invention. The top view which shows the structure of the coil unit which concerns on the said Embodiment 1. FIG. A-A 'arrow sectional view of FIG. Sectional drawing which shows the other structure of the linear conductor of the coil unit which concerns on the said Embodiment 1. FIG. Sectional drawing which shows the other structure of the linear conductor of the coil unit which concerns on the said Embodiment 1. FIG. Sectional drawing which shows the structure which used the coil unit which concerns on the said Embodiment 1 as a primary side power transmission coil of a power transmission apparatus, and a secondary side power reception coil of an electronic device. Circuit diagram for measuring the power transmission efficiency of the coil unit according to the first embodiment. The figure which shows the magnetic flux generation of the magnetic flux generation path of the coil unit which concerns on the said Embodiment 1 by simulation The figure which shows the magnetic flux generation of the magnetic flux generation path of the coil unit which concerns on the said Embodiment 1 by simulation The figure which shows the transmission characteristic of the coil unit which concerns on the said Embodiment 1. The figure which shows the transmission characteristic of the coil unit which concerns on the said Embodiment 1. The figure which shows the transmission characteristic of the coil unit which concerns on the said Embodiment 1. The figure which shows the transmission characteristic of the coil unit which concerns on the said Embodiment 1. The figure which shows the transmission characteristic of the coil unit which concerns on the said Embodiment 1. The figure which shows the transmission characteristic of the coil unit which concerns on the said Embodiment 1. Main configuration diagram of electronic device and power transmission device of wireless power transmission device including coil unit according to embodiment 2 of the present invention The figure which shows the structure of a wireless power transmission apparatus provided with the coil unit which concerns on the said Embodiment 2. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a perspective view showing a configuration of a coil unit according to Embodiment 1 of the present invention. 2 is a plan view of the coil unit according to the present embodiment, and FIG. 3 is a cross-sectional view taken along the line AA ′ in FIG. Hereinafter, an example in which a coil unit according to the present invention is embodied by a planar coil applied to a wireless power transmission device will be described.

As shown in FIGS. 1 to 3, the coil unit 100 is a primary power transmission coil or a secondary power reception coil.

The coil unit 100 is formed by winding a linear conductor 110 in a spiral shape (spiral shape), and a planar spiral coil in which an interline magnetic body 120 (first magnetic body) is interposed between the lines of the linear conductor 110. 111, a magnetic sheet 130 (second magnetic body) covering one surface of the planar spiral coil 111, a start terminal 140 connected to the start end 110a of the linear conductor 110, and an end 110b of the linear conductor 110 And a terminal terminal 150 connected thereto.

Here, the plane spiral coil 111 is formed by winding the linear conductor 110. The planar spiral coil 111 is produced by winding the linear conductor 110 and the inter-line magnetic body 120 together. Alternatively, the planar spiral coil 111 is manufactured by inserting the interline magnetic body 120 between the lines of the linear conductor 110.

The magnetic material sheet 130 is a magnetic material layer provided on the surface opposite to the power transmission / reception surface of the flat spiral coil 111, and suppresses unnecessary radiation due to the magnetic field generated by the linear conductor 110. The magnetic sheet 130 is made of a magnetic material such as a silicon steel plate or an amorphous metal.

The configuration of the coil unit 100 will be described in more detail.

Generally, a high frequency current of several tens to several hundreds kHz is applied to the power transmission coil. When a high-frequency current is passed through a linear conductor 110 in which a single wire is wound to form a coil, if a current in the same direction flows parallel to two or more adjacent linear conductors 110, the current distribution in the conductor cross section Becomes a shape biased toward the central axis, and the resistance value of the coil unit 100 increases and the so-called proximity effect that the loss increases tends to appear.

By providing a certain gap between the linear conductors 110 constituting the coil unit 100, the proximity effect between the wires can be suppressed. Thereby, the resistance value of the coil unit 100 can be reduced and resistance loss can be suppressed. However, the inductance of the coil unit 100 also tends to decrease, and there is a limit to increasing the Q value of the coil unit 100.

(1) In the coil unit 100, a high magnetic permeability interline magnetic body 120 is interposed between the linear conductors 110. Thereby, a magnetic field concentrates on the line | wire magnetic body 120, and interference of the magnetic flux between adjacent conducting wire patterns can be suppressed. As a result, the proximity effect is suppressed, an increase in the resistance value at the linear conductor 110 can be prevented, the inductance of the coil unit 100 can be increased, and the Q value of the coil unit 100 can be increased. And since the generated magnetic flux concentrates on the inter-line magnetic body 120, the concentrated magnetic flux can further strengthen the electromagnetic coupling with the secondary coil on the power receiving side.

(2) In the coil unit 100, when the maximum cross-sectional length of the linear conductor 110 forming the planar spiral coil 111 is Wc and the width of the magnetic body 120 interposed between the linear conductors 110 is Wg, The structure satisfies the relationship.
0.2 ≦ Wg / Wc ≦ 3.5

By setting the width Wg of the interline magnetic body 120 to be not less than 0.2 times and not more than 3.5 times the cross-sectional maximum length Wc of the linear conductor 110, the effect of suppressing the proximity effect and the generated magnetic field Are concentrated on the inter-line magnetic body 120 to achieve both effects of strengthening electromagnetic coupling with the secondary coil on the power receiving side. When it is shorter than 0.2 times, the proximity effect suppressing effect is weakened, and when it is larger than 3.5 times, the effect of concentrating the generated magnetic field on the interline magnetic body 120 tends to be weakened.

(3) The coil unit 100 is provided with a magnetic sheet 130 on the surface opposite to the power transmission / reception surface of the planar spiral coil 111.

With this configuration, the inductance of the coil unit 100 can be increased, the Q value of the coil unit 100 can be increased, and the generated magnetic flux is concentrated on the inter-line magnetic body 120, so that the concentrated magnetic flux is connected to the secondary coil on the power receiving side. The electromagnetic coupling can be made stronger. Further, by providing a low permeability magnetic body (second magnetic body) on the opposite side of the transmission surface of the coil unit 100, leakage of magnetic flux generated from the coil unit 100 can be reduced and a magnetic shielding effect can be exhibited. Furthermore, it is possible to improve the transmission efficiency by increasing the coupling coefficient between the coil units of high frequency components, and to reduce the noise. As a result, the directivity of the magnetic flux can be increased and the propagation loss can be reduced.

(4) The magnetic permeability of the line magnetic body 120 of the coil unit 100 is higher than the magnetic permeability of the magnetic sheet 130. Specifically, the magnetic permeability of the magnetic material of the interline magnetic body 120 is 1000 [H / m] or more and 3000 [H / m] or less, and the magnetic permeability of the magnetic material of the magnetic material sheet 130 is 50 [H / m]. / M] or more and 500 [H / m] or less.

With the configuration in which the magnetic sheet 130 having a lower magnetic permeability than the inter-line magnetic body 120 is provided on the side opposite to the power transmission / reception surface of the coil unit 100, the generated magnetic field is concentrated on the inter-line magnetic body 120, thereby suppressing the proximity effect. In addition to preventing an increase in the resistance value at the conductor 110, the concentrated magnetic flux can further strengthen the electromagnetic coupling with the secondary coil on the power receiving side. In addition, the leakage of magnetic flux generated from the coil unit 100 can be reduced to exhibit the magnetic shielding effect, and the directivity of the magnetic flux can be increased to increase the transmission efficiency.

If the magnetic permeability of the interline magnetic body 120 is smaller than 1000 [H / m], the effect of preventing an increase in resistance value in the linear conductor 110 is difficult to be exhibited, and electromagnetic coupling with the secondary coil on the power receiving side is difficult. There is a tendency that the effect of strengthening is weakened. Further, if the magnetic permeability of the interline magnetic body 120 is larger than 3000 [H / m], the material cost of the magnetic sheet 130 itself increases.

When the magnetic permeability of the magnetic sheet 130 is smaller than 50 [H / m], the effect of increasing the inductance characteristics in the power transmission direction in the coil unit 100 tends to be weakened. When the magnetic permeability of the magnetic sheet 130 is larger than 500 [H / m], the magnetic shield function of the surface outside the power transmission direction tends to be weakened.

Hereinafter, a specific structure of the coil unit 100 of the present embodiment will be described.

As shown in FIG. 2, the coil unit 100 was formed in a circular shape by winding a linear conductor 110, which is a coil wire, in a spiral shape from the start terminal 140 to the end terminal 150. At this time, winding was performed in such a manner that a certain line gap was maintained between the linear conductors 110 forming the coil unit 100, and the inter-line magnetic body 120 was present in the gap.

As shown in FIG. 3, in the coil unit 100, a certain gap is provided between the linear conductor 110 and the adjacent linear conductor 110, and the inter-line magnetic body 120 is interposed in the gap. Further, the magnetic sheet 130 is provided on the surface opposite to the direction of the power transmission / reception surface.

The linear conductor 110 is composed of a single strand having a certain thickness, a rectangular shape, a plurality of thin strands arranged, or a litz wire bundled with a plurality of strands. It can be configured.

FIG. 3 shows a configuration using a rectangular linear conductor 110 such as a square as a preferable configuration. The area that the conducting wire per unit cross-sectional area can occupy increases, and the effect of increasing the inductance of the coil unit 100 can be obtained. And the inductance of the coil unit 100 can be raised by interposing the high magnetic permeability line magnetic body 120 between the rectangular line magnetic bodies 120. In addition, the effect of concentrating the magnetic field by the interline magnetic body 120 is obtained, whereby the proximity effect is suppressed, and the effect of preventing the resistance value increase in the linear conductor 110 can be obtained.

4 and 5 are cross-sectional views showing a configuration of a linear conductor of another coil unit according to the present embodiment.

As shown in FIG. 4, the coil unit 100A has a linear conductor 110A made of one strand.

Further, as shown in FIG. 5, the coil unit 100B has a linear conductor 110B in which a plurality of thin strands are arranged. In FIG. 5, the linear conductor 110B is a strand in which four wires are arranged in parallel. It is also preferable that the linear conductor 110B has a litz wire configuration in which a plurality of strands are bundled and wound.

The coil unit 100 according to the present embodiment employs a configuration in which an interline magnetic body 120 such as ferrite is interposed between the linear conductors 110. With this configuration, the inductance of the coil unit 100 can be increased. Moreover, the resistance loss of the coil unit 100 can be reduced, the Q value of the coil unit 100 can be improved, and the transmission efficiency can be improved.

Here, the cross-sectional width Wc of the linear conductor 110 and the width Wg of the interline magnetic body 120 interposed between the linear conductors 110 will be described.

The coil unit 100 of the present embodiment has the following relationship, where Wc is the cross-sectional width of the linear conductor 110 forming the coil, and Wg is the width of the interline magnetic body 120 interposed between the linear conductors 110. It is preferable to have a configuration that satisfies the above.
0.2 ≦ Wg / Wc ≦ 3.5

By setting the width Wg of the interline magnetic body 120 to be not less than 0.2 times and not more than 3.5 times the maximum cross-sectional length Wc of the linear conductor 110, the proximity effect is suppressed and the coil unit 100 While reducing the loss resistance, the range in which the effect of increasing the inductance of the coil unit 100 was further clarified was clarified. The generated magnetic field is concentrated on the interline magnetic body 120 to further strengthen the electromagnetic coupling with the secondary coil on the power receiving side. If it is shorter than 0.2 times, the proximity effect suppressing effect is weakened, and if it is larger than 3.5 times, the effect of concentrating the generated magnetic field on the interline magnetic body 120 tends to be weakened when the coil unit 100 inductance is reduced. . Preferably, the width Wg of the interline magnetic body 120 is not less than 0.4 times and not more than 2.5 times the maximum cross-sectional length Wc of the linear conductor 110, more preferably the width Wg of the interline magnetic body 120 is linear. The cross section maximum length Wc of the conductor 110 is 0.6 times or more and 1.5 times or less.

The magnetic permeability of the interline magnetic body 120 is preferably 1000 [H / m] or higher, and the magnetic permeability of the magnetic sheet 130 is preferably 50 [H / m] or higher and 500 [H / m] or lower. .

With this configuration, the generated magnetic field is concentrated on the interline magnetic body 120 to suppress the proximity effect, prevent an increase in the resistance value in the linear conductor 110, and the concentrated magnetic flux is electromagnetically coupled to the secondary coil on the power receiving side. Can be made stronger. In addition, a configuration in which leakage of magnetic flux generated from the coil unit 100 can be reduced and the magnetic shielding effect can be exhibited, and the directivity of the magnetic flux is increased to increase the transmission efficiency is clarified.

If the magnetic permeability of the interline magnetic body 120 is less than 1000, the effect of preventing an increase in the resistance value of the linear conductor 110 is difficult to be exhibited, and the effect of strengthening the electromagnetic coupling with the secondary coil on the power receiving side is weakened. There is a tendency. When the magnetic permeability of the magnetic sheet 130 is smaller than 50 [H / m], the effect of improving the inductance characteristics in the power transmission direction in the coil unit 100 tends to be weakened. When the magnetic permeability of the magnetic sheet 130 is larger than 500 [H / m], the magnetic shield function of the surface outside the power transmission direction tends to be weakened.

The magnetic permeability of the interline magnetic body 120 is preferably 3000 [H / m] or less. If it is larger than 3000 [H / m], the transmission efficiency tends to be lowered.

As the magnetic material, Ni—Zn ferrite, Mn—Zn ferrite, Mg—Zn ferrite sheet, etc. can be used. Amorphous metal can also be used as the magnetic sheet. When ferrite is used as the magnetic body, it is advantageous in that the AC resistance of the coil unit 100 is reduced. When amorphous metal is used as the magnetic body, the coil unit 100 can be thinned.

Also, the magnetic flux generated from the primary power transmission coil for power transmission passes through the interline magnetic body 120 and goes out from the end of the interline magnetic body 120 to the front without passing to the opposite surface. The magnetic flux emitted from the front surface is converged to the secondary power receiving coil on the power receiving side. As the magnetic material, it is preferable to use a ferrite made of a crystal of a compound containing an iron oxide, particularly a Ni—Zn ferrite having a large specific resistance and a small eddy current loss inside the ferrite. Moreover, the thing of the structure like the green sheet which disperse | distributed the ferrite particle which is a magnetic body in resin can make magnetic permeability (micro) low.

Next, a method for manufacturing the coil unit 100 of the present embodiment will be described.

First, a dry film resist is applied to the entire surface of the magnetic sheet 130, portions other than the wiring pattern are subjected to heat curing or ultraviolet curing, and non-parts are removed by etching treatment. Thereafter, a sandblast treatment with silica fine particles can be performed to provide a spiral groove having a width of about 0.1 to 1 mm. The linear conductor 110 is inserted into the groove and fixed. The coil unit 100 can be obtained by fixing the magnetic sheet 130 having a certain thickness and magnetic permeability on the surface opposite to the direction of power transmission by bonding or the like.

Further, in order to form a concave portion having a certain depth in the ferrite substrate, a nonmagnetic insulator (dielectric material or the like) having the shape is embedded in an unfired magnetic material, and the ferrite substrate is fired. Thereafter, the nonmagnetic insulator is removed by a process such as sandblasting (powder beam), laser, or etching. The linear conductor 110 can be inserted and fixed in the removed concave spiral pattern. Alternatively, instead of inserting the linear conductor 110, a conductor layer made of Cu or the like is formed by performing processing such as plating, vapor deposition, and sputtering on the entire surface of the ferrite substrate. Subsequently, the surface is polished so that the conductor remains only in the groove of the concave portion, and the portion other than the conductor of the groove portion is deleted to form a spiral conductor to obtain a coil portion. After that, an epoxy resin containing ferrite magnetic powder having a certain thickness and permeability on the surface opposite to the direction of power transmission is applied onto the coil by a screen printing method or the like, and thermally cured (for example, About 150 ° C.), an epoxy resin layer containing ferrite magnetic powder having a certain thickness can be formed on the coil.

Next, the case where the coil unit 100 is used as a primary power transmission coil of a power transmission device or a secondary power reception coil of an electronic device will be described.

As shown in FIG. 1, the coil unit 100 includes a linear conductor 110 that is a planar spiral coil, a line magnetic body 120 interposed between the lines of the linear conductor 110, and the line conductor 110 and the line magnetic body. The magnetic sheet 130 which covers one surface of 120, the start terminal 140, and the termination terminal 150 are provided.

The start terminal 140 and the termination terminal 150 are electrically connected to a power transmission circuit unit or a power reception circuit unit (not shown). The magnetic flux generated from the coil unit 100 is directed in the Z-axis direction perpendicular to the paper surface.

FIG. 6 is a cross-sectional view showing a configuration in which the coil unit 200 is used as a primary power transmission coil 210 of a power transmission device and a secondary power reception coil 220 of an electronic device.

As shown in FIG. 6, the coil unit 200 includes a primary power transmission coil 210 that transmits power by electromagnetic induction, a secondary power reception coil 220 that receives power from the primary power transmission coil 210, and a primary side. A power transmission device housing 230 that houses the power transmission coil 210 and an electronic device housing 240 that houses the secondary power receiving coil 220 are provided.

The primary power transmission coil 210 is formed by winding a linear conductor 110 in a spiral shape (spiral shape), and a planar spiral coil 111 in which a magnetic body 120 is interposed between the lines of the linear conductor 110, and a planar spiral coil. And a magnetic material sheet 130 </ b> A covering one surface of 111. The primary power transmission coil 210 is installed on the inner surface of the housing 230 of the power transmission device so that the magnetic material sheet 130 </ b> A side is accommodated.

The secondary power receiving coil 220 is formed by winding a linear conductor 110 in a spiral shape, and a planar spiral coil 111 having a magnetic body 120 interposed between the lines of the linear conductor 110 and a line between the linear conductors 110. And a magnetic sheet 130 </ b> B that covers one surface of the planar spiral coil 111.

In the above configuration, the power transmission device housing 230 and the electronic device housing 240 are close to each other and electromagnetically coupled to each other, so that power can be transmitted wirelessly.

Hereinafter, the wireless power transmission according to the present invention will be described with more specific examples.

[Example 1]
Wireless power transmission was evaluated using the coil unit 100 shown in FIG. The evaluation was performed under the condition that the switching frequency was 150 kHz, the transmission distance between the primary side power transmission coil and the secondary side power reception coil was 40 mm, and the transmission power from the power transmission device was 20 W.

FIG. 7 is a circuit diagram for measuring the power transmission efficiency of the coil unit 100.

In the measurement circuit 250 of FIG. 7, the power transmission efficiency (η = V ₂ × I ₂ / V ₁ × I ₁ ) was measured.

The measurement circuit 250 includes a constant voltage power source 251, a power transmission circuit 252, and a primary power transmission coil 210 on the power transmission side, and a secondary power reception coil 220, a power reception circuit 253, and a load 254 on the power reception side.

The current (I ₁ ) and voltage (V ₁ ) supplied from the constant voltage source 251 by the constant voltage power supply 251 are sent to the primary power transmission coil 210 through the power transmission circuit 252. And the electric power transmission efficiency was measured from the voltage (V ₂ ) applied to the voltage (V ₂ ) applied to the current (I ₂ ) and the load 254 through the power receiving circuit 253 for the voltage induced in the secondary side receiving coil 220 by electromagnetic induction.

Table 1 shows the coil characteristics in Comparative Example 1-3 and Example 1. Wc [mm] indicates the maximum width of the coil unit 100, in this case, the diameter of the conducting wire. Wg [mm] indicates a gap between adjacent linear conductors 110 constituting the coil unit 100 or a width of the inter-line magnetic body 120 interposed in the gap. When the coil unit 100 is circular, the inner diameter R1 [mm] and the outer diameter D1 [mm], and when the coil unit 100 is a rectangular coil, the inner diameter corresponds to N1, and the outer diameter corresponds to M1. Re [Ω] is the resistance of the coil unit 100, Q is the Q value of the coil unit 100, and η [%] is the transmission efficiency of power transmission.

Comparative Example 1 is a conventional coil unit. This coil unit has a configuration in which a linear conductor having a diameter of 0.6 mm is wound in a spiral shape.

Comparative Example 2 has a configuration in which the magnetic sheet 13 having a permeability of 2200 [H / m] and a thickness of 0.8 mm is disposed on the side opposite to the power transmission surface in the conventional coil unit.

Comparative Example 3 is another conventional coil unit. In this coil unit, a spiral pattern groove is formed on an epoxy resin substrate, and a linear conductor having a diameter of 0.6 mm is wound spirally around the groove, and a certain gap Wg is provided between adjacent linear conductors. This is a configuration provided.

Example 1 shows the coil characteristics of the coil unit 100 shown in FIGS. The coil unit 100 forms a planar coil by spirally winding a linear conductor 110 having a diameter of 0.6 mm on a magnetic sheet 130 having a magnetic permeability of 400, and passes through a gap Wg between adjacent linear conductors 110. This is a configuration in which a linear magnetic body 120 having a magnetic permeability of 2800 [H / m] and a thickness of 0.8 mm is interposed.

As described above, the coil unit 100 first applies a dry film resist to the entire surface of the magnetic sheet 130, performs UV curing on portions other than the wiring pattern, and removes the wiring portion by etching. Then, a spiral groove having a width of 0.6 mm is provided by sandblasting with silica fine particles. The linear conductor 110 is inserted into the groove and fixed. And the magnetic body sheet 130 of thickness 0.8mm was fixed to the surface opposite to the electric power transmission direction by adhesion | attachment etc., and the coil unit 100 shown in FIG. 3 was obtained.

As shown in Table 1, in Comparative Example 2, when the magnetic sheet 130 is disposed on the surface opposite to the power transmission surface of the coil unit 100, the coil inductance increases. However, the loss resistance of the coil unit 10 increases, and as a result, the Q value of the coil unit 100 decreases and the transmission efficiency decreases. In Comparative Example 3, the coil inductance is reduced by providing a certain gap between the adjacent linear conductors 110. By suppressing the proximity effect, the loss resistance of the coil unit 200 is reduced, the Q value of the coil unit 100 is increased, and the transmission efficiency is improved.

In contrast to the comparative example 1-3, the coil unit 100 of the first embodiment has a coil inductance increased by interposing the interline magnetic body 120 between the adjacent linear conductors 110, but the coil inductance increases. As the Q value of the coil is increased, the effect of improving the transmission efficiency is obtained.

8 and 9 are diagrams showing the magnetic flux generation in the magnetic flux generation path of the coil unit by simulation. FIG. 8 shows magnetic flux generation in the magnetic flux generation path when a certain gap is provided between the linear conductors 110 of the coil unit 200 of Comparative Example 3. In FIG. 9, the linear conductor 110 is spirally wound on the magnetic sheet 130 of the coil unit 100 of the first embodiment, and the interline magnetic body 120 is interposed in the gap between the adjacent linear conductors 110. The magnetic flux generation of the magnetic flux generation path in the case is shown.

As shown in FIG. 9, strong magnetic flux is generated from the vicinity of the coil unit 100, and a state in which it is guided upward is observed.

Table 2 shows the coil characteristics when the Wg of the coil unit 100 is changed. N1 and M1 are the inner side length and the outer side length shown in FIG.

FIG. 10 is a diagram showing the transmission characteristics of the coil unit 100. The horizontal axis represents the ratio (Wg / Wc) of the width Wg of the interline magnetic body 120 to the cross-sectional maximum width Wc of the linear conductor 110, and the vertical axis represents the resistance value Re [Ω] of the coil unit 100 of each example.

As shown in FIG. 10, with the increase in Wg / Wc, that is, with respect to the maximum cross-sectional width length Wc of the linear conductor 110, the width of the interline magnetic body 120 interposed in the interval between the adjacent linear conductors 110. As Wg is increased, the resistance value of the coil unit 100 tends to decrease. This is considered to be an effect of suppressing the proximity effect between adjacent linear conductors 110.

FIG. 11 is a diagram showing the transmission characteristics of the coil unit 100. The horizontal axis represents Wg / Wc, and the vertical axis represents the Q value of each coil.

As shown in FIG. 11, with the increase in Wg / Wc, the decrease in inductance of the coil unit 100 is suppressed, and the coil Q value increases due to the decrease in coil resistance. Although it tends to decrease slightly from the constant Wg / Wc, the high Q value of the coil is maintained as a whole.

FIG. 12 is a diagram showing the transmission characteristics of the coil unit 100. The horizontal axis represents Wg / Wc, and the vertical axis represents the transmission efficiency.

As shown in FIG. 12, it shows a tendency similar to the Q value of the coil, and it is possible to maintain high transmission efficiency as a whole.

As described above, the coil unit 100 according to the first embodiment has a coil loss by providing a gap between the adjacent linear conductors 110 and interposing the interline magnetic body 120 with respect to the comparative example 1-3 described above. Although the resistance tends to increase slightly, the coil inductance increases and the coil Q value becomes higher, so that the effect of improving the transmission efficiency is obtained.

Table 3 shows the characteristics of the coil unit 100 when the magnetic permeability (μ1) of the interline magnetic body 120 and the magnetic permeability (μ2) of the magnetic body B in FIG. 3 are changed.

FIG. 13 is a diagram showing the transmission characteristics of the coil unit 100. The horizontal axis represents the magnetic permeability of the interline magnetic body 120 and the magnetic permeability (μ1 / μ2) of the magnetic sheet 130, and the vertical axis represents the coil resistance value Re (Ω).

As shown in FIG. 13, as the magnetic permeability increases, the coil resistance value tends to increase slightly.

FIG. 14 is a diagram showing the transmission characteristics of the coil unit 100. The horizontal axis represents the magnetic permeability of the interline magnetic body 120 and the magnetic permeability of the magnetic sheet 130 (μ1 / μ2), and the vertical axis represents the Q value of each coil.

As shown in FIG. 14, when [mu] 1 / [mu] 2 is a constant high value, the high inductance value of the coil dominates and tends to maintain a high coil Q value. As μ1 / μ2 decreases, it tends to decrease slightly, but the high Q value of the coil is maintained as a whole.

FIG. 15 is a diagram showing the transmission characteristics of the coil unit 100. The horizontal axis represents the magnetic permeability of the interline magnetic body 120 and the magnetic permeability (μ1 / μ2) of the magnetic sheet 130, and the vertical axis represents the transmission efficiency.

As shown in FIG. 15, it shows a tendency similar to the Q value of the coil, and it is possible to maintain high transmission efficiency as a whole.

Thus, by providing a gap between the adjacent linear conductors 110, interposing the interline magnetic body 120, and using the interline magnetic body 120 having a certain permeability, a high coil inductance causes a high coil Q. The value can be held, and the effect of improving the transmission efficiency can be obtained.

As described in detail above, according to the present embodiment, the coil unit 100 is formed by winding the linear conductor 110 into a spiral planar curved line, and the magnetic body 120 between the lines of the linear conductor 110. And a magnetic sheet 130 that covers a surface opposite to the power transmission / reception surface of the planar spiral coil 111. When the maximum cross-sectional length of the linear conductor 110 is Wc and the width of the interline magnetic body 120 is Wg, 0.2 ≦ Wg / Wc ≦ 3.5. Further, the magnetic permeability of the line magnetic body 120 is 1000 [H / m] or more and 3000 [H / m] or less, and the magnetic permeability of the magnetic sheet 130 is 50 [H / m] or more and 500 [H / m]. It is the following.

With this configuration, the following effects can be obtained.

(1) Between adjacent linear conductors, the current distribution in the conductor cross section is biased toward the central axis, and the resistance value of the coil tends to increase. Therefore, by providing a certain gap between the linear conductors 110 constituting the coil, it is possible to suppress the proximity effect between the wires and suppress the resistance loss.

(2) By interposing the high-permeability inter-line magnetic body 120 between the lines of the linear conductor 110, the magnetic field concentrates on the inter-magnetic line magnetic body 120. As a result, the proximity effect is suppressed, and an increase in resistance value in the linear conductor 110 can be prevented. Further, the generated magnetic flux is concentrated on the interline magnetic body 120, and the concentrated magnetic flux can further strengthen the electromagnetic coupling with the secondary coil on the power receiving side.

(3) By covering the surface opposite to the power transmission / reception surface of the linear conductor 110 with the magnetic sheet 130 having a lower magnetic permeability than the interline magnetic body 120 interposed between the linear conductors 110, the linear conductor is covered. The leakage of magnetic flux generated from 110 can be reduced and the magnetic shielding effect can be exhibited. Moreover, the directivity of magnetic flux can be improved and the inductance of a coil can be made high. As a result, it is possible to increase the Q value of the coil transmission characteristics and to reduce the propagation loss.

From the above, even when the coil unit 100 is used for high-power wireless power transmission, it is possible to suppress a decrease in power transmission efficiency, and long-distance power transmission between the primary side and secondary side coils is possible. It becomes possible. Moreover, even if there is a slight misalignment between the primary side and secondary side coils, there is an excellent effect that the power transmission efficiency is not greatly reduced.

(Embodiment 2)
In the first embodiment, the coil unit 100 has been described.

Embodiment 2 describes a wireless power transmission device including a coil unit 100.

16 and 17 are diagrams showing a configuration of a wireless power transmission device including the coil unit according to the second embodiment of the present invention. FIG. 16 is a main configuration diagram of the electronic device and the power transmission device of the wireless power transmission device, and FIG. 17 is a control circuit diagram of wireless power transmission between the charging device and the electronic device terminal. The same components as those in FIG. 6 are denoted by the same reference numerals.

16 and 17, the wireless power transmission device 300 includes a power transmission device 310 and an electronic device 320 that is a power reception device.

The power transmission device 310 and the electronic device 320 form a wireless power transmission device that wirelessly transmits power by electromagnetic induction coupling.

<Power transmission device 310>
The power transmission device 310 is a charging device on which the electronic device 320 is placed and charges the secondary battery 321 of the electronic device 320.

The power transmission device 310 includes a primary power transmission coil 210, a power transmission control unit 312, and a power transmission circuit unit 313.

The primary side power transmission coil 210 is a wireless power transmission coil on the power transmission side when charging the secondary battery 321 of the electronic device 320. The primary power transmission coil 210 uses the coil unit 100 of the first embodiment.

The power transmission control unit 312 supplies power to the primary power transmission coil 210 and controls it.

<Electronic device 320>
The electronic device 320 is a power receiving side electronic device. Here, the present invention is applied to an electronic device having a built-in secondary battery 321 for power storage as a load in the electronic device.

The electronic device 320 includes a circuit board including a secondary power receiving coil 220, a secondary battery 321, and a charge control circuit 322.

The secondary-side power receiving coil 220 is a power-receiving-side wireless power transmission coil that serves as a power-receiving side when the secondary battery 321 is charged, and uses the coil unit 100 of the first embodiment.

The secondary battery 321 generates operating power for the terminal.

Next, the operation of the wireless power transmission device 300 will be described.

When the secondary power reception coil 220 of the electronic device 320 approaches the primary power transmission coil 210 of the power transmission device 310, an AC voltage is induced in the secondary power reception coil 220 by electromagnetic induction coupling of both coils. The induced AC voltage is supplied to the power receiving circuit unit 323.

The AC voltage of 100 [V], which is the commercial power supply 311, is converted into a predetermined DC voltage by an AC / DC converter (not shown), the DC voltage is generated as an AC voltage having a predetermined frequency, and the generated AC voltage is generated. To the power transmission circuit unit 313. The generated AC voltage is supplied from the power transmission circuit unit 313 to the primary side power transmission coil 210, and causes the primary side power transmission coil 210 to oscillate at a predetermined resonance frequency. The capacity of the resonance capacitor can be determined from the carrier frequency F [Hz] of the power transmission signal and the inductance of the coil, and is given by F = 1 / 2π√LC.

On the other hand, in the electronic device 320, an AC voltage is induced in the secondary power receiving coil 220 by the oscillation of the primary power transmitting coil 210 of the power transmitting device 310. The induced AC voltage is rectified through a rectifier circuit (not shown), and the secondary battery 321 is charged with the DC voltage smoothed by the smoothing circuit.

Here, before an AC voltage is induced in the secondary power receiving coil 220 by the oscillation of the primary power transmission coil 210 of the power transmission device 310 and the secondary battery 321 is charged, the electronic device 320 serving as the power reception device transmits the power transmission device 310. It is detected that it is installed on the terminal mounting table.

First, the electronic device 320 is placed on the terminal mounting base of the power transmission device 310, and the secondary side power receiving coil 220 of the electronic device 320 and the primary side power transmission coil 210 of the power transmission device 310 are disposed close to each other. Due to this proximity arrangement, the load impedance changes, and the voltage or current value fluctuates in the primary side power transmission coil 210. The power transmission control unit 312 detects the presence of the electronic device 320 to be charged by comparing the fluctuation value with a predetermined value.

Similarly, in the electronic device 320 on the power receiving side, the electronic device 320 is placed on the terminal mounting base of the power transmission device 310, and the secondary power receiving coil 220 and the primary power transmission coil 210 are disposed in proximity to each other. A change in voltage or current value generated in the primary side power transmission coil 210 due to a change in load impedance is detected. The power reception control circuit 322 compares the fluctuation value with a predetermined value and detects that the electronic device 320 is placed on the mounting table of the power transmission device 310 that is a charging device.

When the electronic device 320 is placed on the mounting table of the power transmission device 310, highly efficient power transmission is performed by placing the coils in an appropriate proximity. However, when the electronic device 320 is placed at an inappropriate position, the power transmission efficiency tends to decrease. For this reason, it is preferable to notify the user whether or not it is placed in an appropriate positional relationship by some method, and to prompt the user to place it in an appropriate position.

The wireless power transmission device 300 according to the present embodiment does not greatly reduce power transmission efficiency even if there is a slight misalignment between both coils. Transmission efficiency can be obtained.

In addition, in the wireless power transmission device 300 according to the present embodiment, the power transmission device 310 and the electronic device 320 can transmit information signals regarding both devices via the primary power transmission coil 210 and the secondary power reception coil 220. It is. For example, when the primary-side power transmission coil 210 and the secondary-side power reception coil 220 are arranged close to each other, the voltage fluctuation at that time is detected and an appropriate arrangement is detected, the primary-side power transmission coil 210 and the secondary-side power reception coil The identification information of each device and apparatus is exchanged between the coils 220 to mutually authenticate each other. When the primary side power transmission coil 210 and the secondary side power reception coil 220 are detected to be appropriately arranged close to each other and the respective devices and devices can authenticate each other, the secondary side from the primary side power transmission coil 210 Power is transmitted to the side power receiving coil 220, and the secondary battery 321 of the electronic device 320 is charged with the transmitted power.

Next, control of wireless power transmission between the power transmission device 310 and the electronic device 320 will be described.

As shown in FIG. 17, the power transmission device 310 includes a power transmission control unit 312, a power transmission circuit unit 312, and a primary side power transmission coil 210.

AC voltage supplied from the commercial power supply 311 is converted into a predetermined DC voltage through an AC / DC converter (not shown). This DC voltage is supplied to the power transmission circuit unit 312 via the power transmission control unit 312.

The power transmission circuit unit 313 has at least a driver and a resonance circuit (both not shown). The driver converts the DC voltage from the AC / DC converter into an AC voltage having a predetermined frequency under the control of the power transmission control unit 312. The resonance circuit resonates according to the AC voltage from the driver by a resonance circuit composed of a capacitor C and an inductance L of the coil. Thereby, the primary side power transmission coil 210 is oscillated at a predetermined resonance frequency.

In addition, the power transmission circuit unit 313 superimposes a modulation signal including information on the state of the device supplied from the power transmission control unit 312 and information on the AC signal for power transmission, or electronically only the information alone. Information transmission to the device 320 can also be performed.

When transmitting charging power from the power transmission device 310 to the electronic device 320, the power transmission control unit 312 controls the driver of the power transmission circuit unit 313 and supplies an AC voltage of a predetermined frequency from the driver to the primary power transmission coil 210. Let In addition, the power transmission control unit 312 detects voltage or current fluctuations generated in the primary power transmission coil 210 due to the close arrangement or movement of the electronic device 320 to the mounting table of the power transmission device 310. Then, based on the detection of the close arrangement and movement of the electronic device 320 to the mounting table of the power transmission device 310, the control of the supply and stop of the AC voltage from the driver to the primary power transmission coil 210 is performed. Furthermore, the power transmission control unit 312 has a modulation / demodulation circuit (not shown) that transmits information on each device state between the power transmission device 310 and the electronic device 320. Information is transmitted from the primary side power transmission coil 210 to the secondary side power reception coil 220 by generating and transmitting a signal modulated according to information on the state of the device.

On the contrary, when receiving device information from the electronic device 320, the modulation signal sent from the electronic device 320 is taken out, the modulation signal is demodulated by the modulation / demodulation circuit, and the information sent from the electronic device 320 is received. Is called.

Meanwhile, the electronic device 320 mainly includes a secondary power receiving coil 220, a power receiving circuit unit 323, a power receiving control unit 324, a charging control circuit 322, and a secondary battery 321.

The power receiving circuit unit 323 includes a rectifier circuit (not shown) that converts an alternating voltage induced in the secondary power receiving coil 220 into a direct voltage by electromagnetic induction from the primary power transmitting coil 210, and a direct current sent from the rectifier circuit. It is comprised from the regulator (not shown) which converts a voltage into the predetermined voltage used by charge of the electronic device 320. FIG. In addition, a resonance circuit and a driver (both not shown) of the secondary power receiving coil 220 for sending device state information to the power transmission device 310 are provided.

The DC voltage converted into a predetermined voltage by the regulator is sent to the power reception control unit 324. The power reception control unit 324 sends the power received by the power reception circuit unit 323 to the charge control circuit 322 and charges the secondary battery 321. In addition, the power reception control unit 324 detects a device state of the electronic device 320, for example, a temperature rise, a charging state of the secondary battery 321, a voltage variation generated in the secondary power receiving coil 220, and the like. Furthermore, the power reception control unit 324 includes a modulation / demodulation circuit (not shown) that sends a signal modulated according to the device information to the power transmission device 310 to the power reception circuit unit 323.

When the oscillation circuit of the power reception circuit unit 323 transmits information from the electronic device 320 to the power transmission device 310, the driver causes the power reception control unit 324 to resonate the resonance circuit so that the secondary side reception coil 220 has a predetermined resonance frequency. Oscillate with. The driver transmits a modulation signal for information transmission supplied from the power reception control unit 324.

Transmission / reception of information signals between the power transmission apparatus 310 and the electronic device 320 may be simple bit communication or coded communication.

Further, in the present embodiment, the power transmission device 310 is used when the voltage value based on the change in the load impedance does not become a predetermined voltage value determined in advance or when the identification and authentication between the devices cannot be performed. It is controlled not to supply power to the primary side power transmission coil 210 as being in some abnormal state.

In the present embodiment, an AC voltage is induced in the secondary power receiving coil 220 by the electromagnetic induction coupling between both the primary power transmitting coil 210 and the secondary power receiving coil 220 and is supplied to the power receiving circuit unit 323. When the secondary battery 321 of the electronic device 320 is charged, the secondary battery 321 is interposed between the power transmission device 310 and the electrical device 2 via the primary side power transmission coil 210 and the secondary side power reception coil 220. The charging information is transmitted. For example, when the secondary battery 321 needs to be continuously charged, the power transmission from the primary power transmission coil 210 is continued. Further, when the charging of the secondary battery 321 is completed, the power transmission is stopped. Control is also performed to stop power transmission when information indicating some abnormality is supplied.

In this embodiment, an example in which the coil unit is used for a charging device and an electronic device or a wireless power transmission device has been described. However, the coil unit may be applied to any electronic device such as a portable terminal. Any device may be used as long as the device transmits electric power in a non-contact manner by electromagnetic induction. For example, the device may be applied to a mobile terminal device such as a mobile phone. As a matter of course, the coil unit may be either a power transmission coil or a power reception coil.

The above description is an illustration of a preferred embodiment of the present invention, and the scope of the present invention is not limited to this.

In the above embodiments, the names of the coil unit and the power transmission device are used. However, this is for convenience of explanation, and the coil unit is a planar coil, a power transmission coil or a power reception coil, and the power transmission device is a wireless power transmission device. A non-contact power transmission system or the like may be used.

Furthermore, the parts constituting the coil unit, for example, the type / shape of the linear conductor, the inter-line magnetic body, the magnetic sheet, and the mounting method are not limited to the above-described embodiment. The linear conductor may be formed by being spirally wound, and the shape may be a circle or a polygon including a rectangle.

The disclosures of the description, drawings and abstract contained in the Japanese application of Japanese Patent Application No. 2012-083960 filed on April 2, 2012 are incorporated herein by reference.

The coil unit and the power transmission device according to the present invention are detachably mounted or approached to a power transmission device such as a charging device, so that the electronic device or the like as a power reception target is detachably attached to the electronic device from the power transmission device by electromagnetic induction. The present invention can be applied to a coil unit for transmitting electric power and a power transmission device including the coil unit in general.

100, 100A, 100B, 200

Coil unit

110, 110A, 110B Linear conductor 111 Planar spiral coil 120 Interlinear magnetic body (first magnetic body)
130, 130A, 130B Magnetic sheet (second magnetic body)
140 Start terminal 150 Termination terminal 210 Primary power transmission coil 220 Secondary power reception coil 300 Wireless power transmission device 310 Power transmission device 312 Power transmission control unit 313 Power transmission circuit unit 320 Electronic device 321 Secondary battery 322 Charge control circuit 323 Power reception circuit unit 324 Power reception control unit

Claims

A planar coil formed by spirally winding a linear conductor;
A first magnetic body interposed between lines of the linear conductor;
A second magnetic body provided to cover one surface of the planar coil;
A coil unit comprising:
When the maximum cross-sectional length of the linear conductor is Wc and the width of the first magnetic body is Wg, the following relationship is satisfied:
The coil unit according to claim 1.
0.2 ≦ Wg / Wc ≦ 3.5
The coil unit according to claim 1, wherein the magnetic permeability of the first magnetic body is higher than the magnetic permeability of the second magnetic body.
The magnetic permeability of the first magnetic body is 1000 [H / m] or more and 3000 [H / m] or less, and the magnetic permeability of the second magnetic body is 50 [H / m] or more and 500 [H / m]. The coil unit according to claim 3, wherein m] or less.
A power transmission coil configured using the coil unit according to claim 1, wherein a surface of the planar coil opposite to the surface facing the second magnetic body is disposed on a power transmission surface, and the power transmission coil A power transmission section for supplying power to
Power transmission device including
A power receiving coil configured using the coil unit according to claim 1, wherein a surface of the planar coil opposite to the surface facing the second magnetic body is disposed on a power receiving side surface, and the power receiving coil A power receiving device that outputs the power received at
Power transmission device including