JP2012005308A - Wireless power transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a relative positional relationship between a power receiving coil and a power transmission coil.SOLUTION: A wireless power transmission system includes a power receiving device 20 which is installed on a mobile body and contains a power receiving coil 103, and power transmission device 10 which contains a power transmission coil 102 that supplies power to the power receiving coil 103 in non-contact manner. The wireless power transmission system further includes a first antenna 301 which is arranged close to the power transmission coil 102 and contains a plurality of loop antenna elements in which loop axes are orthogonal to each other, a second antenna 304 which is arranged close to the power receiving coil 102 and contains a plurality of loop antenna elements in which the coil axis direction of the power receiving coil 102 almost agrees with the respective loop axis directions, and a position calculation means 308 which, based on the reception magnetic field generated by the plurality of loop antenna elements of the first antenna 301, acquires a relative positional relationship between the power transmission coil 102 and the power receiving coil 103.

Description

  The present invention relates to a wireless power transmission system capable of detecting a positional relationship between a power transmission coil and a power reception coil.

  In recent years, wireless power transmission systems have been developed for non-contact charging of, for example, electric vehicles. In this wireless power transmission system, a power transmission coil is provided on the charging device side, and a power reception coil is provided on the electric vehicle side. By using an electromagnetic induction method, high-efficiency transmission efficiency has been realized without contact. However, in this wireless power transmission system using electromagnetic induction, it is known that the transmission efficiency is greatly deteriorated due to, for example, the displacement of the power receiving coil with respect to the power transmitting coil.

  In order to prevent the deterioration of transmission efficiency, conventionally, a positional shift is detected by electrically detecting a change in mutual inductance caused by a positional shift between both coils, and the operation of the system is controlled (for example, Patent Document 1, 2 and 3).

JP 2002-101578 A Japanese Patent Laid-Open No. 10-322247 JP 2008-288889 A

  However, in the methods of Patent Documents 1, 2, and 3 described above, even though the positional deviation between the two coils can be detected, for example, the position of the power receiving coil with respect to the power transmitting coil cannot be known. I couldn't.

  In view of the above-described conventional problems, an object of the present invention is to provide a wireless power transmission system that can detect the relative positions of both coils.

  In order to solve the above-described problems, the present invention provides a wireless power transmission system including a power receiving device installed on a moving body and having a power receiving coil, and a power transmitting device having a power transmitting coil that supplies power to the power receiving coil in a non-contact manner. A first antenna having a plurality of loop antenna elements that are installed in any one of the power receiving device and the power transmitting device and whose loop axes are orthogonal to each other, and any of the power receiving device and the power transmitting device A second antenna having at least one loop antenna element that is installed on the other side and that has a loop axis direction substantially coincident with a coil axis direction of a power reception coil or a power transmission coil provided in either one of the power reception device and the power transmission device; A plurality of loop antenna elements included in the first antenna or a loop antenna included in the second antenna. Based on the received magnetic field, and a position calculation means for calculating a relative positional relationship between the power transmission coil and the power receiving coil.

  With the above configuration, according to the present invention, it is possible to obtain the relative positional relationship between the power receiving coil and the power transmitting coil.

The figure which shows the structure of the wireless power transmission apparatus in Embodiment 1 of this invention. The figure which shows the structure of the 1st antenna 301 in Embodiment 1 of this invention. The figure which shows the structure of the 2nd antenna 304 in Embodiment 1 of this invention. The figure which showed the positional information detection procedure of the receiving coil 103 in Embodiment 1 of this invention. The figure which showed vector distribution of the magnetic field from the loop antenna element 304a in Embodiment 1 of this invention The figure which showed the vector distribution of the magnetic field in XY plane from loop antenna element 304a, 304b in Embodiment 1 of this invention, and the positional relationship of loop antenna element 304a, 304b, 304c. The figure which showed the positional information detection procedure of the receiving coil 103 in Embodiment 1 of this invention. The figure which showed the example of mounting to the car 400 in Embodiment 1 of this invention

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for implementing a wireless power transmission device of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
Details of Embodiment 1 of the wireless power transmission system of the present invention will be described below.

  FIG. 1 is a diagram showing a configuration of a wireless power transmission system of the present invention. In FIG. 1, the wireless power transmission system includes a power transmission device 10 arranged at a predetermined location and a power reception device 20 installed on the moving body side. Here, the present wireless power transmission system is typically applied to a non-contact power feeding system of an electric propulsion vehicle such as an electric vehicle. In this case, the power reception device 20 is installed in an electric propulsion vehicle as a moving body, and the power transmission device 10 is typically fixedly installed in a parking lot. The power transmission device 10 is not limited to being fixed, and may be configured to be movable.

  The power transmission device 10 includes a high-frequency oscillation source 101, a power transmission coil 102, a first antenna 301, a position calculation unit 308, a power transmission side position information notification unit 309, a power transmission side GPS receiver 311, and a power transmission side wireless communication. Means 202 and power transmission side control means 201 are provided.

  The power receiving device 20 includes a power receiving coil 103, a load circuit 104, a second antenna 304, a magnetic field output unit 307, a power receiving side position information notifying unit 310, a power receiving side GPS receiver 312, and a power receiving side wireless. Communication means 204 and power receiving side control means 203 are provided.

  The high frequency oscillation source 101 is an oscillation source that generates and outputs high frequency power. The power transmission coil 102 is connected to the high frequency oscillation source 101 and generates a high frequency magnetic field.

  The power receiving coil 103 is a coil that receives power from the magnetic field generated from the power transmitting coil 102. The load circuit 104 is a circuit including a rectifier circuit, a battery, and the like that are connected to the power receiving coil 103 and supply electric power obtained from the power receiving coil 103.

  The power transmission side control unit 201 includes, for example, a microcomputer and a processor, and performs various processes described later. As an example, the power transmission side control unit 201 exchanges control information with a power reception side control unit 203 described later using a power transmission side wireless communication unit 202 which is a wireless communication unit.

  The power receiving side control means 203 includes, for example, a microcomputer and a processor, and performs various processes described later. As an example, the power receiving side control unit 203 exchanges control information with the power transmission side control unit 201 using the power receiving side wireless communication unit 204 which is a wireless communication unit.

  The power transmission-side wireless communication unit 202 may perform wireless communication using a first antenna 301 described later. The power receiving side wireless communication unit 204 may perform wireless communication using a second antenna 304 described later.

  The first antenna 301 is an antenna that is disposed in the vicinity of the power transmission coil 102 and detects the direction of a magnetic field generated by a second antenna 304 described later.

  FIG. 2 is a diagram illustrating a configuration of the first antenna 301. X, Y, and Z indicate respective coordinate axes, and the X axis, the Y axis, and the Z axis are orthogonal to each other. In FIG. 2, the first antenna 301 includes loop antenna elements 301 a, 301 b, 301 c, a magnetic body 302, and a conductor plate 303.

  The loop antenna element 301 a is a loop antenna whose loop axis direction is the Z-axis direction and substantially coincides with the coil axis direction of the power transmission coil 102. The loop antenna element 301b is a loop antenna whose loop axis direction is the Y-axis direction. The loop antenna element 301c is a loop antenna whose loop axis direction is the X-axis direction. Thus, the first antenna 301 is an antenna including a plurality of loop antenna elements whose loop axes are orthogonal to each other.

  The magnetic body 302 is a magnetic body disposed on the back surface of the loop antenna element 301a. As a result, the loop antenna element 301a can be prevented from generating eddy currents on the back surface. In FIG. 2, the back surface is a surface on the negative side of the Z axis with respect to the loop antenna element 301a.

  The conductor plate 303 is a plate-like conductor disposed on the back side of the loop antenna element 301 a and on the negative side of the Z axis of the magnetic body 302. Thereby, the influence on the characteristic by the change of the electrical constant of the member arrange | positioned at the back surface of the loop antenna element 301a can be prevented.

  Refer to FIG. 1 again. The second antenna 304 is an antenna that is disposed in the vicinity of the power receiving coil 103 and includes a plurality of loop antenna elements.

  Here, FIG. 3 is a diagram illustrating a configuration of the second antenna 304. Assume that the X axis, Y axis, and Z axis shown in FIG. 3 face the same direction as the X axis, Y axis, and Z axis shown in FIG. The second antenna 304 includes loop antenna elements 304a, 304b, and 304c, magnetic bodies 305a, 305b, and 305c, and a conductor plate 306.

  The loop antenna elements 304 a, 304 b, and 304 c are loop antennas whose loop axis direction substantially coincides with the coil axis direction of the power receiving coil 103.

  The magnetic bodies 305a, 305b, and 305c are disposed on the back surface of the loop antenna elements 304a, 304b, and 304c for the same reason as the loop antenna element 301a.

  The conductor plate 306 is disposed on the back surface of the loop antenna elements 304a, 304b, and 304c for the same reason as the loop antenna element 301a.

  Refer to FIG. 1 again. The magnetic field output means 307 is an oscillation source that generates high-frequency power and outputs it to the second antenna 304. As a result, a magnetic field is output from the second antenna 304. The magnetic field output means 307 selects and outputs one of a plurality of loop antenna elements (see FIG. 3) included in the second antenna 304.

  The position calculation means 308 includes, for example, a microcomputer and a processor, and the power receiving coil 103 is obtained from the strength of each magnetic field received from a plurality of loop antenna elements of the first antenna 301 that have mutually orthogonal loop axes. The position of is calculated.

  The power transmission side position information notification unit 309 includes a display and a speaker connected to the power transmission side control unit 201. The power transmission side position information notifying unit 309 outputs the position information of the power receiving coil 103 as sound or an image from a speaker or a display and notifies the user.

  The power receiving side position information notifying unit 310 includes a display and a speaker connected to the power receiving side control unit 203. The power receiving side position information notifying unit 310 outputs the position information of the power receiving coil 103 as a sound or an image from a speaker or a display and notifies the user.

  The power transmission-side GPS receiver 311 is a GPS receiver that is connected to the power transmission-side control means 201 and outputs position data (hereinafter referred to as position data) where it is present by receiving radio waves from GPS satellites.

  The power-receiving-side GPS receiver 312 is connected to the power-receiving-side control means 203, and is a GPS receiver that outputs position data on which it is present by receiving radio waves from GPS satellites.

  The operation of the wireless power transmission apparatus configured as described above will be described.

  First, a case where only the loop antenna elements 304a and 304b of the second antenna 304 are used will be described. FIG. 4 is a diagram illustrating a procedure for detecting position information of the power receiving coil 103.

  First, in step 1, the power transmission side control unit 201 and the power reception side control unit 203 determine the distance between the power transmission device 10 and the power reception device 20 from the position data output by the power transmission side GPS receiver 311 and the power reception side GPS receiver 312. calculate. In order to calculate the distance, the power transmission side control unit 201 sends the output position data of the power transmission side GPS receiver 311 to the power receiving device 20 via the power transmission side wireless communication unit 202. In the power receiving device 20, the power receiving side control unit 203 receives the position data from the power transmitting device 10 via the power receiving side wireless communication unit 204, and the received position data and the output position data of the power receiving side GPS receiver 312. Is used to calculate the distance between the power transmission device 10 and the power reception device 20. The power transmission side control unit 201 also receives the position data of the power receiving device 20 in the same manner, and calculates the distance between the power transmitting device 10 and the power receiving device 20 using this.

  When the calculated distance is equal to or smaller than a predetermined distance, the power receiving device 20 and the power receiving device 10 are regarded as being in an area close to each other, and the power transmitting control unit 201 and the power receiving control unit 203 start detecting position information. To do. An area where the power receiving device 20 and the power transmitting device 10 are close to each other depending on whether or not wireless communication is possible between the power transmitting side control unit 201 and the power receiving side control unit 203 via the power transmitting side wireless communication unit 202 and the power receiving side wireless communication unit 204. The power transmission side control means 201 and the power reception side control means 203 may start position information detection.

  In step 2, the magnetic field output means 307 generates high frequency power and outputs it to the loop antenna element 304a. The loop antenna element 304a outputs a magnetic field according to the applied high frequency power.

  In step 3, the position calculation means 308 receives the magnetic field from the loop antenna element 304a by the first antenna 301, and measures the magnetic field strength for each of the X, Y, and Z components. Here, the loop antenna element 301a extracts the Z component Hz of the magnetic field. The loop antenna element 301b extracts the Y component Hy of the magnetic field. The loop antenna element 301c extracts the X component Hx of the magnetic field.

  In step 4, the position calculation means 308 calculates the distance and direction between the loop antenna element 304 a and the first antenna 301 from the magnetic field strength measurement result obtained in step 3.

  Here, FIG. 5 is a diagram showing the distribution of the magnetic field vector H from the loop antenna element 304a. The Z-direction component Hz of the magnetic field vector becomes stronger as it approaches the center of the loop, and becomes weaker as it goes away. The component Hxy in the XY plane becomes dominant. The component Hxy in the XY plane of the magnetic field is calculated by the following equation (1).

Hxy = √ (Hx ² + Hy ² ) (1)
The distance between the loop antenna element 304a and the first antenna 301 is calculated by calculating the ratio of Hz and Hxy.

  FIG. 6 is a diagram showing the magnetic field vector distribution in the XY plane from the loop antenna elements 304a and 304b and the positional relationship between the loop antenna elements 304a, 304b and 304c. The magnetic field vector H in the XY plane spreads radially around the loop antenna element 304a. The arc tangent function of the ratio of Hx and Hy is calculated, and the direction from the loop antenna element 304a to the first antenna 301 is calculated. Further, by calculating the distance r1 and the direction θ1 between the loop antenna element 304a and the first antenna 301, the positional relationship between the two is reduced to four patterns (A1, B1, C1, D1) as shown in FIG. .

  Referring to FIG. 4 again, in step 5, the magnetic field output means 307 generates high frequency power and outputs it to the loop antenna element 304b. The loop antenna element 304b outputs a magnetic field according to the applied high frequency power.

  In step 6, the position calculation means 308 receives the magnetic field from the loop antenna element 304b by the first antenna 301, and measures the magnetic field strength for each of the X, Y, and Z components.

  In step 7, the position calculation means 308 calculates the distance and direction between the loop antenna element 304 b and the first antenna 301 from the measurement result of the magnetic field strength obtained in step 6. The calculation procedure is the same as in step 4. By calculating the distance r2 and the direction θ2 between the loop antenna element 304b and the first antenna 301, the positional relationship between them is reduced to four patterns (A2, B2, C2, D2) as shown in FIG.

  In step 8, the position calculation unit 308 calculates position information of the power receiving coil 103. Of the positional relationship of each of the four patterns narrowed down in step 4 and step 7, the pattern that satisfies both is narrowed down to one (B2, C1). From this, the positional relationship (r1, θ1) = (r2, θ2) between the loop antenna elements 304a, 304b and the first antenna 301 can be obtained. In this manner, the position of the power receiving coil 103 relative to the power transmitting coil 102 is calculated from the positional relationship between the power receiving coil 103 and the loop antenna elements 304a and 304b.

  In step 9, the power transmission side position information notifying unit 309 and the power receiving side position information notifying unit 310 notify the user or the like of the position information of the power receiving coil 103.

  Further, when it is a precondition that the first antenna 301 is in an area with the loop antenna elements 304a and 304b as diagonals, only the direction between the loop antenna elements 304a and 304b and the first antenna 301 is calculated. Thus, the positional relationship between the two can be obtained. Therefore, the calculation of the distance in steps 4 and 7 and the measurement of the magnetic field strength of the Z direction component in steps 3 and 6 can be omitted.

  Next, detection of position information of the power receiving coil 103 when the loop antenna elements 304a, 304b, and 304c of the second antenna 304 are used will be described.

  FIG. 7 is a diagram illustrating a procedure for detecting position information of the power receiving coil 103.

  Steps 11 to 17 are the same as steps 1 to 7 in FIG.

  In step 18, the magnetic field output means 307 generates high frequency power and outputs it to the loop antenna 304c. The loop antenna element 304c outputs a magnetic field according to the input high frequency power.

  In step 19, the position calculation means 308 receives the magnetic field from the loop antenna element 304c by the first antenna 301, and uses the same method as in step 6 to set the magnetic field strength for each of the X, Y, and Z components. taking measurement.

  In step 110, the position calculation means 308 calculates the distance between the loop antenna element 304c and the first antenna 301 from the obtained measurement result of the magnetic field strength.

  In step 111, the position calculation unit 308 calculates position information of the power receiving coil 103. The positions satisfying the distances obtained in step 14, step 17, and step 110 are narrowed down to one. Thus, the positional relationship between the loop antenna elements 304a, 304b, 304c and the first antenna 301 can be obtained. The position of the power receiving coil 103 is calculated from the positional relationship between the power receiving coil 103 and the loop antenna elements 304a, 304b, and 304c.

  Since step 112 is the same as step 9 in FIG. 4, its detailed description is omitted.

  Note that the configuration example in which the first antenna 301 and the position calculation unit 308 are provided on the power transmission coil 102 side, and the second antenna 304 and the magnetic field output unit 307 are provided on the power reception coil 103 side. The antenna 301, the position calculation means 308, and the second antenna 304 and the magnetic field output means 307 may be provided on the power transmission coil 102 side.

  In addition, although the detection method in the case where there are two loop antenna elements and there are three loop antenna elements has been described, three or more may be used.

  FIG. 8 is a diagram showing an example of mounting the wireless power transmission system of the present invention on an electric propulsion vehicle (hereinafter simply referred to as a vehicle) 400. A plurality of power transmission coils 102a, 102b, and 102c are mounted on the ground side, and the power receiving coil 103 is mounted on the vehicle 400 side. The position of the power receiving coil 103 is calculated by the above procedure, and the high-frequency oscillation source 101 selects the power transmitting coil closest to the power receiving coil 103 among the plurality of power transmitting coils and transmits power to the power receiving coil 103. Although the case where a plurality of power transmission coils are used has been described, a plurality of power reception coils may be used.

  As described above, the wireless power transmission system of the present invention can realize the position detection of the coil.

  In the above embodiment, the application example to the non-contact power feeding system of the electric propulsion vehicle has been described. However, the present invention is not limited thereto, and for example, the power receiving device 20 is installed in a mobile device as another example of the moving body. In addition, the power transmission device 10 may be installed in a charger for the portable device.

  In the above embodiment, an example in which one first antenna 301 is arranged and configured as shown in FIG. 2 and a plurality of second antennas 304 is arranged as shown in FIG. 3 has been described. Since the position can be calculated if there are two or more different positional relationships between the first antenna and the second antenna, the configuration is not limited to this, and a plurality of the first antennas are arranged as shown in FIG. However, one second antenna may be arranged as shown in FIG.

  In the above embodiment, the first antenna 301 is provided in the vicinity of the power receiving coil 103, and the second antenna 304 is provided in the vicinity of the power transmitting coil 102. However, if the relative positional relationship between the power receiving coil 103 and the power transmitting coil 102 is obtained as in the present invention, the first antenna 301 is provided in the power receiving device 20 and the second antenna 304 is provided in the power transmitting device 10. It only has to be done.

  The wireless power transmission system of the present invention can detect the position of a coil. Therefore, the wireless power transmission system of the present invention can be applied as a non-contact charger such as a portable device or an electric propulsion vehicle.

DESCRIPTION OF SYMBOLS 101 High frequency oscillation source 102, 102a, 102b, 102c Power transmission coil 103 Power reception coil 104 Load circuit 201 Power transmission side control means 202 Power transmission side wireless communication means 203 Power reception side control means 204 Power reception side wireless communication means 301 First antenna 301a, 301b, 301c Loop antenna element 302, 305a, 305b, 305c Magnetic body 303, 306 Conductor plate 304 Second antenna 304a, 304b, 304c Loop antenna element 307 Magnetic field output means 308 Position calculation means 309 Power transmission side position information notification means 310 Power reception side position Information notification means 311 Power transmission side GPS receiver 312 Power reception side GPS receiver 400 Electric propulsion vehicle

Claims (10)

A wireless power transmission system comprising a power receiving device installed on a moving body and having a power receiving coil, and a power transmitting device having a power transmitting coil that supplies power to the power receiving coil in a contactless manner,
A first antenna that is installed in any one of the power receiving device and the power transmitting device and has a plurality of loop antenna elements each having a loop axis orthogonal to each other;
At least one of the power receiving device and the power transmitting device, which is installed on the other side of the power receiving device and the power transmitting device, and the coil axis direction of the power receiving coil or power transmitting coil provided on the other side of the power receiving device and the power transmitting device substantially coincides with each loop axis direction A second antenna having a loop antenna element;
A position calculating means for obtaining a relative positional relationship between the power transmission coil and the power reception coil based on a reception magnetic field by a plurality of loop antenna elements of the first antenna or a loop antenna of the second antenna; Wireless power transmission system. The first antenna is configured to extract components in directions orthogonal to each other from an output magnetic field of the second antenna using the plurality of loop antennas,
The said position calculating means is comprised so that the distance and direction from the said power transmission coil to the said receiving coil may be calculated | required using each component extracted by the said 1st antenna. Wireless power transmission system. The second antenna is configured to output a magnetic field via the second loop antenna element after outputting a magnetic field via the first loop antenna element;
The first antenna first extracts components in directions orthogonal to each other from the output magnetic field of the first loop antenna element of the second antenna as a first component, and then extracts the second antenna of the second antenna. A component that is orthogonal to each other is extracted from the output magnetic field of the loop antenna element as a second component,
The position calculating means is configured to obtain a distance and a direction from the power transmission coil to the power reception coil by using the first component and the second component extracted by the first antenna. The wireless power transmission system according to claim 1. The wireless power transmission system further includes power receiving side position detecting means for outputting position data where the power receiving apparatus exists, and power transmission side position detecting means for outputting position data where the power transmitting apparatus exists,
When the distance between the power receiving apparatus and the power transmitting apparatus obtained based on the position data from the power receiving side position detecting means and the position data from the power transmitting side position detecting means is equal to or less than a predetermined distance, The wireless power transmission system according to claim 1, configured to determine a relative positional relationship between the power transmission coil and the power reception coil. Installed on the power receiving device side and installed on the power transmitting device side, and / or on the power receiving device position information notifying means for outputting a relative positional relationship between the power transmitting coil and the power receiving coil obtained by the position calculating means. The wireless power transmission system according to claim 1, further comprising power transmission side position information notification means for outputting a relative positional relationship between the power transmission coil and the power reception coil obtained by the position calculation means. The first antenna is installed in one of the power receiving coil and the power transmitting coil,
The second antenna is installed on one of the power receiving coil and the power transmission coil, and a plurality of loops in which the coil axis directions of the other coil axis of the power receiving coil and the power transmission coil substantially coincide with each other. The wireless power transmission system according to claim 1, comprising an antenna element. A power receiving device installed in a moving body,
A power receiving coil that receives power from a power transmitting coil provided in an external power transmitting device in a contactless manner;
An antenna having a plurality of loop antenna elements in which the respective loop axes are orthogonal to each other;
A power receiving apparatus comprising: a position calculating unit that obtains a relative positional relationship between the power transmitting coil and the power receiving coil based on a reception magnetic field by a plurality of loop antenna elements included in the antenna. A power transmission device that supplies power in a non-contact manner to a power receiving device installed in a moving body,
A power transmission coil for supplying power to a power reception coil provided in the power reception device;
An antenna having a plurality of loop antenna elements in which the respective loop axes are orthogonal to each other;
A power transmission apparatus comprising: a position calculation unit that obtains a relative positional relationship between the power transmission coil and the power reception coil based on a reception magnetic field by a plurality of loop antenna elements of the antenna. A power receiving device installed in a moving body,
A power receiving coil that receives power from a power transmitting coil provided in an external power transmitting device in a contactless manner;
An antenna having at least one loop antenna element in which the coil axis direction of the power receiving coil and each loop axis direction substantially coincide with each other;
A power receiving apparatus comprising: a position calculating unit that obtains a relative positional relationship between the power transmission coil and the power receiving coil based on a received magnetic field by a loop antenna included in the antenna. A power transmission device that is installed in a mobile body and supplies power to a power reception device in a contactless manner,
A power transmission coil for supplying power to a power reception coil provided in the power reception device;
An antenna having at least one loop antenna element in which the coil axis direction of the power transmission coil and each loop axis direction substantially coincide with each other;
A power transmission apparatus comprising: a position calculation unit that obtains a relative positional relationship between the power transmission coil and the power reception coil based on a reception magnetic field by a loop antenna included in the antenna.

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