JP2013135523A - Wireless power feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge a range for the size of a power receiver to which a power feeder is capable of supplying power, by enabling a wireless power feeding device to supply power also to a power receiver smaller than a power receiver size assumed by the power feeder.SOLUTION: A converter 130 is provided between a power feeder 110 and a power receiver 120. The converter 130 is functioned by a magnetic circuit to enlarge an apparent size of the power receiver 120 from the power feeder 110.

Description

  The present invention relates to an electromagnetic induction type wireless power feeding that transmits power to the near field without being connected.

  As a method for transmitting power to the near field without connection, a magnetic field resonance method, an electric field resonance method, an electromagnetic induction method, and the like are widely known. In the magnetic field resonance method, development relating to power feeding to a moving body such as a car, which has a high degree of freedom in the spatial positional relationship between the power feeder and the power receiver and is difficult to accurately align, has been actively performed. In addition, products have been developed that use a magnetic resonance method to feed power to 3D glasses that do not have a flat contact surface. As the electric field resonance method, a method in which a power feeder is embedded in a table, a wall, or the like and is in close contact with the power receiver or a method in which power is supplied to a tablet terminal or the like has been developed.

  On the other hand, in the electromagnetic induction system, the standardization movement is progressing. Conventionally, when charging a portable device incorporating a secondary battery, a dedicated AC converter or the like that is different for each portable device has been used as a power feeder. For this reason, the number of AC converters increases, and the user has to perform a complicated operation of finding a corresponding AC converter and connecting a connector.

  By standardizing the wireless power supply specification and supplying power to a general-purpose power supply without connecting to the connector, the convenience can be greatly improved. Since power can be supplied simply by placing any power receiver that satisfies the standardized specification on top of any power supply that satisfies the standardized specification, the convenience for the user is greatly improved.

  An example of such a conventional wireless power supply apparatus 601 will be described with reference to FIG. In the figure, a wireless power feeding apparatus 601 includes a power feeder 110 and a power receiver 620 (see, for example, Patent Document 1).

  The power feeder 110 includes a power feeding surface 111, a detection electrode 112, detection means 113, first power conversion means 114, a primary coil 115, and first control means 116. In the power feeder 110, when the power receiver 620 to be fed is placed on the upper power feeding surface 111, the detection unit 113 detects a change in the electrical signal from the detection electrode 112. When the detection unit 113 detects that the power receiver 620 is placed, the first control unit 116 starts power supply by the first power conversion unit 114. The first power conversion means 114 converts power stored in an external power source or an internal battery into high-frequency power. The converted electric power is converted into magnetic flux by the primary coil 115 and output from the contact surface.

  The power receiver 620 includes a power receiving surface 121, a secondary coil 625, second power conversion means 124, power storage means 127, and second control means 126. The secondary coil 625 disposed so as to face the primary coil 115 is coupled to the primary coil 115 by mutual inductance, and converts the magnetic flux from the primary coil into high-frequency power. The high frequency power from the secondary coil 625 is converted into DC power by the second power conversion means 124. That is, power is transmitted by the mutual inductance of the primary coil 115 and the secondary coil 625. The transmitted power is used as a power source for the circuit of the entire power receiver 620 and is stored in the power storage unit 127. The second control means 126 performs management of the state of the power storage means 127, control of communication with the power feeder 110, and the like. The communication with the power feeder 110 is performed by, for example, changing the load of the second power conversion unit 124 of the power receiver 620 to check the power supply target and control the power.

  Here, in order to increase the mutual inductance between the primary coil 115 and the secondary coil 625 and increase the coupling coefficient between the primary coil 115 and the secondary coil 625, the size of the primary coil 115 and the secondary coil 625 is increased. It should be almost the same. For this reason, the sizes of the primary coil 115 and the secondary coil 625 are generally substantially the same. Specifically, both the primary coil and the secondary coil were about 30 mm in size. However, since the secondary coil 625 is incorporated in the power receiver 620, the power receiver 620 having an outer shape smaller than the secondary coil 625 cannot be formed.

  Therefore, in the power receiver 620 smaller than the primary coil 115, since the secondary coil 625 is further smaller than the power receiver 620, there is a problem that the coupling coefficient is reduced and efficient power feeding cannot be performed. In addition, when the power receiver 620 is smaller than the power feeder 110 assumes, there is a problem that the power receiver 620 may not be detected.

JP 2010-183706 A

  Therefore, the present invention solves the problems of the conventional wireless power feeder described above, and even when a power receiver having a secondary coil smaller than that assumed by the power feeder is set in a general-purpose power feeder, To widen the range of the size of the power receiver that can be fed by a general-purpose power feeder by functioning as if the size of the apparent secondary coil from the electrical device is within the assumption. It is an object to provide a wireless power feeding device using a converter capable of performing the above.

  In a wireless power feeder that transmits power from a power feeder to a power receiver through electromagnetic energy, a power feeder having a primary coil that converts power into electromagnetic energy and outputs the power, and power from the electromagnetic energy Wireless power feeder comprising: a power receiver having a secondary coil for inputting a power supply; and a converter disposed between the power feeder and the power receiver and having a magnetic body that forms a magnetic circuit with the primary coil and the secondary coil. Configure.

  In the wireless power feeding apparatus according to the present invention, even when a power receiver having an unexpectedly small secondary coil is set in a general-purpose power feeder, the size of the electromagnetic apparent secondary coil from the power feeder is not assumed. By inserting a converter that functions as if, a general-purpose power feeder can widen the range of the size of the power receiver that can be fed.

1 is a block diagram showing a preferred embodiment of a wireless power supply apparatus according to the present invention. The block diagram which shows an example of a structure of the converter which concerns on this invention The block diagram which shows an example of the function of the converter which concerns on this invention The block diagram which shows the other example of a structure of the converter which concerns on this invention The block diagram which shows the other example of the function of the converter which concerns on this invention Block diagram of a conventional wireless power supply device

  A wireless power feeder according to the present invention includes a power feeder that converts electric power into electromagnetic energy and outputs the power, a power receiver that inputs electric power from electromagnetic energy, and a detachable device between the power feeder and the power receiver. A wireless power feeder is configured by a converter that is arranged and functions so that an electromagnetic apparent size from the power feeder becomes larger than that of the power receiver.

In the following description of the present embodiment, () is used as a heading.
(Wireless power supply apparatus 101)
FIG. 1 shows a preferred embodiment of a wireless power feeder 101 according to the present invention. The wireless power feeder 101 transmits power from the power feeder 110 to the power receiver 120 through electromagnetic energy.

  A wireless power feeder 101 according to the present invention includes a power feeder 110 that converts electric power into electromagnetic energy and outputs the power, a power receiver 120 that receives power from electromagnetic energy, and the power feeder 110 and the power receiver 120. The converter 130 is detachably disposed between the power supply units 110 and functions so as to increase the electromagnetic apparent size.

(Power feeder 110)
The power feeder 110 includes a power feeding surface 111, a detection electrode 112, detection means 113, first power conversion means 114, a primary coil 115, and first control means 116. In the power feeder 110, when a power supply target is placed on the power supply surface 111, the detection unit 113 detects a change in the electrical signal from the detection electrode 112. The detection target here refers to the one in which the power receiver 120 is set in the converter 130. When the first control unit 116 detects that the power supply target is placed, the first power conversion unit 114 starts the power supply. The first power conversion means 114 converts power stored in an external power source or an internal battery into high-frequency power. The converted electric power is converted into magnetic energy by the primary coil 115 and output from the contact surface.

  The power feeder 110 according to the present embodiment is a general-purpose power feeder having an outer diameter of the primary coil of 30 mm, and the size of the secondary coil is assumed to be approximately the same. Therefore, as shown in the conventional example, a power receiver having a secondary coil with a size of about 30 mm can be directly fed to the power receiver 620 without the converter 130 as shown in FIG.

(Power receiver 120)
The power receiver 120 includes a power receiving surface 121, a secondary coil 125, second power conversion means 124, power storage means 127, and second control means 126. The secondary coil 125 is disposed so that the winding axis is perpendicular to the power receiving surface 121, and is coupled to the primary coil 115 via the converter 130 to receive power from magnetic energy. The power received by the secondary coil 125 is converted into direct current by the second power conversion means 124. The electric power converted into direct current is used as a power source for the circuit of the entire power receiver 120 and is stored in the power storage means 127. The second control means 126 performs management of the state of the power storage means 127, control of communication with the power feeder 110, and the like. Communication with the power feeder 110 is performed, for example, by changing the load of the second power conversion unit 124 of the power receiver 120. The communication content is the power required by the power receiver 120.

  Compared with a conventional power receiver 620 as shown in FIG. 6, the power receiver 120 of the present embodiment has a small outer shape, so the secondary coil cannot be made sufficiently large. However, when the diameter of the secondary coil is less than half of the diameter of the primary coil, for example, only a part of the magnetic field generated in the primary coil usually intersects with the secondary coil. It is known that transmission becomes difficult. Specifically, it is assumed that the power receiver of this embodiment is built in a portable electronic device such as a wristwatch or a hearing aid, a rechargeable button battery, or the like. For this reason, the size of the secondary coil is about 15 mm or less, which is about a half of the size of the primary coil. Therefore, even if the portable device is arranged such that the power receiving surface of the power receiver is in contact with the power feeding surface of the power feeder without using a converter, it is difficult to perform high-efficiency power transmission.

(Configuration of converter 130)
FIG. 2 shows an example of a cross-sectional configuration of the converter 130. The converter 130 includes a conversion input surface 131 in contact with the power supply surface 111 of the power supply 110, a conversion output surface 132 in contact with the power reception surface 121 of the power receiver 120, and a closed loop due to mutual inductance between the primary coil 115 and the secondary coil 125. The circular first soft magnetic body 231 for reducing the magnetic resistance of one of the two paths of the magnetic circuit and the circular second soft magnetic body 232 for reducing the magnetic resistance of the other path are mainly configured. Element. In the example of FIG. 2, the two paths of the closed-loop magnetic circuit are a path from the inside of the primary coil to the inside of the secondary coil, and a path from the outside of the primary coil to the outside of the secondary coil.

In FIG. 2, the dimension A is the inner dimension of the second soft magnetic body on the conversion input surface 131 side, and is approximately the same length as the outer dimension of the primary coil 115. Similarly, the dimension B is the inner dimension of the second soft magnetic body on the conversion output surface 132 side, and is approximately the same length as the outer dimension of the secondary coil 125. Therefore, in this embodiment, the dimension B is less than or equal to one half of the dimension A.
In this example, ferrite was used as the soft magnetic material. When the soft magnetic material is a conductor, it is desirable to divide the soft magnetic material in order to reduce eddy currents.

(Magnetic circuit)
FIG. 3 shows an example of a magnetic circuit in the present embodiment. The primary coil 115 is provided with a third soft magnetic body 311. The third soft magnetic body 311 is a circular soft magnetic body having an E-shaped cross section, and a primary coil 115 is wound around a central convex portion. Similarly, the secondary coil 125 is provided with a fourth soft magnetic body 321. The fourth soft magnetic body 321 is a circular soft magnetic body having an E-shaped cross section, and a secondary coil 125 is wound around a central convex portion.

  The third soft magnetic body 311 of the power feeder 110, the first soft magnetic body 231 and the second soft magnetic body 232 of the converter 130, and the fourth soft magnetic body 321 of the power receiver 120 are magnetic as indicated by arrows in FIG. The circuit is configured. However, the arrow indicates the path of the magnetic circuit at a certain moment, and the direction of the arrow has no particular meaning because it is actually an alternating magnetic field.

  In this way, by arranging the magnetic body so that most of the magnetic flux that interlaces with the primary coil 115 interlaces with the secondary coil 125, the electromagnetic appearance from the primary coil 115 side of the secondary coil 125 is obtained. The size of becomes larger. Moreover, since the coupling coefficient of the primary coil 115 and the secondary coil 125 approaches 1, mutual inductance also increases and the efficiency of electric power transmission can be improved.

  The magnetic resistance of the magnetic circuit is such that the relative permeability of the soft magnetic material is sufficiently large, so that the gap between the third soft magnetic body 311 and the first soft magnetic body 231, and the first soft magnetic body 231 and the fourth soft magnetic body. It is the total sum of the magnetic resistances of the four gaps of the gap 321, the gap between the fourth soft magnetic body 321 and the second soft magnetic body 232, and the gap between the second soft magnetic body 232 and the third soft magnetic body 311. By making these magnetic resistances sufficiently small, the mutual inductance of the primary coil 115 and the secondary coil 125 can be further increased. In order to reduce the magnetic resistance of these four gaps, each magnetic body was in a positional relationship with the outer shape so as to face each other in the four gaps.

  As described above, by inserting a converter between the power feeder and the power receiver, the magnetic flux from the large primary coil 115 efficiently interlaces with the small secondary coil 125. It functions so that the apparent size of the electromagnetic power receiver 120 from the electric device 110 is greatly expanded. Here, the electromagnetic apparent size is specifically a range in which the magnetic flux intermingled with the secondary coil 125 enters and exits the power supply surface 111.

(Reduction of leakage magnetic flux)
Also, the corner 331 that is farther from the conversion output surface inside the second soft magnetic body 232 is chamfered, which increases the magnetoresistance between the first soft magnetic body 231 and the second soft magnetic body 232. This is to increase the coupling coefficient between the primary coil 115 and the secondary coil 125 by reducing the leakage magnetic flux. In this way, the configuration is such that the direct magnetic resistance of the first soft magnetic body 231 and the second soft magnetic body 232 is as large as possible so that the leakage magnetic flux is as small as possible.
For this reason, the converter 130 having the configuration shown in FIG. 3 requires a certain height.

(Configuration of other soft magnetic materials)
The example in which the magnetic resistance is minimized when the four soft magnetic bodies 231, 232, 311, 321 have a circular shape sharing the same axis has been described above, but this is not restrictive. Although not shown, for example, even when the circular axes of the third soft magnetic body 311 around which the primary coil 115 is wound and the fourth soft magnetic body 321 around which the secondary coil 125 is wound are displaced, Since the first soft magnetic body 231 and the second soft magnetic body 232 are decentered, the first soft magnetic body 231 and the second soft magnetic body 232 are in the third soft magnetic body 311 on the surface where the power feeding surface and the conversion input surface are in contact with each other. And the first soft magnetic body 231 and the second soft magnetic body 232 may face the fourth soft magnetic body 321 on the surface where the conversion output surface and the power receiving surface are in contact with each other.

  Moreover, although the example in the case where the four soft magnetic bodies 231, 232, 311, 321 are circular has been described above, this is not restrictive. For example, the primary coil 115, the secondary coil 125, and the four magnetic bodies 231, 232, 311 and 321 may be rectangular.

(Positioning method)
The converter 130 is detachably disposed between the power feeder 110 and the power receiver 120, but in order to efficiently supply power while minimizing the magnetic resistance of the four gaps, the power converter 110 and the converter 130 are connected to each other. The position and converter 130 and the power receiver 120 need to have a desired positional relationship. For this purpose, the power supply 110 and the converter 130 are aligned with a displayed guide (not shown), but may be aligned with a guide with unevenness or may be aligned with the force of a magnet. Also good. The same applies to the alignment between the converter 130 and the power receiver 102.

  In order to enhance the convenience for the user, it is desirable that the converter is also general-purpose, and it is desirable that the positioning means be unified so that the same converter can be used even if the power receivers are different.

(When the 3rd and 4th soft magnetic bodies are flat)
FIG. 4 shows another configuration of the third soft magnetic body 411 and the fourth soft magnetic body 421. The third soft magnetic body 411 and the fourth soft magnetic body 421 are not necessarily E-shaped. As shown in FIG. 4, when the primary coil 115 and the secondary coil 125 are thin, for example, a flat circle may be used. In this case, the above-mentioned four gaps are longer than in the case of the E-shape, and the magnetic resistance is increased. When the magnetic resistance of the intended path is increased, the ratio of the magnetic resistance is relatively decreased. For example, the primary coil 115 is caused by a leakage magnetic flux between the first soft magnetic body 231 and the second soft magnetic body 232. As a result, the coupling coefficient of the secondary coil 125 decreases, and the mutual inductance also decreases. Still, when there is no converter, the coupling coefficient and the mutual inductance are reduced by the ratio of the area of the secondary coil. Therefore, the converter improves the coupling coefficient and the mutual inductance.

(Detection of power supply target)
The detection electrodes 112 of the power feeder 110 shown in FIG. 1 are arranged corresponding to two-dimensional coordinates. Therefore, the detection means 113 can detect the position and size of the power supply target from the change in the signal from each detection electrode. When the detected power supply target size is smaller than a predetermined size, there is a possibility of foreign matter, so power supply is not performed. The detection of the power supply target by the detection electrode 112 and the detection means 113 is performed by a change in capacitance. Since the first soft magnetic body 231 and the second soft magnetic body 232 are ferrite and have a volume resistivity of about 0.1 to 1 Ωm, they can be detected as they are due to changes in capacitance. The converter 130 can be detected as a regular power supply target because of the size of the power receiver assumed by the power supply 110. That is, also in the detection of the power supply target, it is possible to increase the electromagnetic apparent size of the power receiver 120 from the power feeder 110 via the converter 130.

  Detection of the power supply target is not necessarily a method based on a change in capacitance, and a change in resonance frequency due to electromagnetic induction may be used.

  In addition, although an example in which a power supply target is detected by the detection electrode 112 is illustrated in FIG. 1, the detection electrode 112 is not necessarily provided when there is a communication unit between the power feeder 110 and the power receiver 120. . The communication means referred to here includes, for example, modulation due to the impedance of power feeding to the power receiver side, or a case where a communication circuit or coil exists independently.

(Other configuration examples of magnetic circuit)
As described above, the two paths in the converter of the closed-loop magnetic circuit due to the mutual inductance of the primary coil 115 and the secondary coil 125 are the path from the inside of the primary coil to the inside of the secondary coil, and Although the example in the case of making the path | route from the outer side to the outer side of a secondary coil shown was shown, it is not this limitation. For example, as shown in FIG. 5, fourth ends extending from both ends of the third soft magnetic body 511 extending through the primary coil 115 and extending from both ends approach the power feeding surface 111 respectively. In the case of a structure in which both ends of the soft magnetic body 521 are close to the power receiving surface 121, as the two paths of the magnetic circuit in the converter 130, The first soft magnetic body 531 is provided so as to face both the one approaching place to the power feeding surface 111 of the three soft magnetic bodies 511 and the one approaching place to the power receiving face 121 of the fourth soft magnetic body 521, and similarly The second soft magnetic body 532 is provided so as to face both the other approaching position of the third soft magnetic body 511 to the power feeding surface 111 and the other approaching position of the fourth soft magnetic body 521 to the power receiving surface 121. do it.

  However, it goes without saying that in this case, each magnetic body is not circular. In this case, as shown by the arrows in FIG. 5, a magnetic circuit including four magnetic bodies is configured, and even when the power receiver 120 is smaller than the size of the third soft magnetic body 511, By making the coupling coefficient of the secondary coil 125 close to 1, the mutual inductance can be increased. In this case, as in the case described above, the arrow indicates the path of the magnetic circuit, and the direction of the arrow has no meaning.

(Summary)
As described above, in the wireless power feeder according to the present invention, even when a power receiver having an unexpectedly small secondary coil is set in a general-purpose power feeder, an electromagnetic apparent secondary from the power feeder. By functioning as if the size of the coil is within the assumption, the range of the size of the power receiver that can be fed by a general-purpose power feeder can be widened.
Although not specifically shown in the present embodiment, when the concept of the present invention is applied, the same effect can be obtained by the same configuration even in wireless power feeding by electric field coupling.

DESCRIPTION OF SYMBOLS 101 Wireless power feeder 110 Power feeder 111 Power feeding surface 112 Detection electrode 113 Detection means 114 First power conversion means 115 Primary coil 116 First control means 120 Power receiver 121 Power reception surface 124 Second power conversion means 125 Secondary coil 126 Second Control means 127 Power storage means 130 Converter 131 Conversion input surface 132 Conversion output surfaces 231, 531 First soft magnetic bodies 232, 532 Second soft magnetic bodies 311, 411, 511 Third soft magnetic bodies 321, 421, 521 Fourth soft Magnetic body 601 Conventional wireless power feeder 620 Conventional power receiver 625 Conventional secondary coil

Claims (6)

In a wireless power feeder that transmits electric power from a power feeder to a power receiver via electromagnetic energy,
A power feeder having a primary coil that converts electric power into electromagnetic energy and outputs it;
A power receiver having a secondary coil for inputting power from the electromagnetic energy;
A wireless power feeder, comprising: a converter disposed between the power feeder and the power receiver and having a magnetic body that forms a magnetic circuit with the primary coil and the secondary coil.   The converter is a magnetic circuit in one path of a magnetic circuit that is a closed loop in which a primary coil that converts electrical energy and magnetic energy is connected to a power source and a secondary coil that converts electrical energy and magnetic energy is a power receiver. The wireless power feeding apparatus according to claim 1, further comprising: a first soft magnetic body that reduces resistance and a second soft magnetic body that reduces magnetic resistance of the other path.   The converter includes a first soft magnetic body that reduces a magnetic resistance between the inner side of the primary coil and the inner side of the secondary coil, and a magnetic field between the outer side of the primary coil and the outer side of the secondary coil. The wireless power feeder according to claim 2, further comprising a second soft magnetic body that reduces resistance.   4. The wireless power feeder according to claim 3, wherein an inner dimension of the first soft magnetic body on a power receiver side is equal to or less than a half of an inner dimension of the power feeder side.   The wireless power feeder according to claim 3, wherein a size of the secondary coil is 15 mm or less.   The wireless power feeder according to any one of claims 1 to 5, wherein the power receiver is a portable electronic device or a rechargeable button battery.

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