JP2012075199A - Wireless power transmission device and wireless power reception device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize deterioration in transmission efficiency and make a resonant frequency of a coil variable.SOLUTION: According to an embodiment of the present invention, a wireless power transmission device comprises a coil and a metal plate. The coil receives supply of high-frequency energy, and transmits the high-frequency energy to a coil of a reception device by means of magnetic coupling. The metal plate is arranged so as to face a part of a first end face, which is one of both end faces of the coil.

Description

  Embodiments described herein relate generally to a wireless power transmission apparatus and a wireless power reception apparatus.

  When wireless power transmission is performed by a coil using a magnetic resonance method, the resonance frequency of the coil may deviate from the design value due to manufacturing variations or an external environment such as a nearby desk. As a result, the transmission efficiency is degraded. There is also a need to change the resonance frequency of the coil when it is desired to change the frequency to be transmitted.

  A method is known in which a capacitor is attached to a coil and the resonance frequency of the coil is varied by changing the value of the capacitor. However, this method has a problem that transmission efficiency deteriorates due to an increase in loss in the coil due to the parasitic resistance of the capacitor.

  In order to allow a large amount of resonance frequency adjustment, a circuit for changing a plurality of capacitors and combinations of the capacitors is required. This complicates the circuit configuration and increases circuit loss. As a result, the transmission efficiency is degraded.

JP 2009-106136 A

  The present invention intends to make the resonance frequency of a coil variable while suppressing deterioration of transmission efficiency.

  A wireless power transmission device as one embodiment of the present invention includes a coil and a metal plate.

  The coil receives supply of high-frequency energy and transmits the high-frequency energy to the receiving device side coil by magnetic coupling.

  The metal plate is disposed so as to face a part of a first end surface which is one end surface of both end surfaces of the coil.

1 is a block diagram of a wireless power transmission system according to a first embodiment. The figure explaining a self-resonance coil and a magnetic force line. The figure explaining how to put the metal plate which self-inductance decreases. The figure explaining how to put the metal plate which self-capacitance increases. The figure which shows the state which has arrange | positioned the metal plate in the center of a plane spiral coil. The figure which shows the state which has arrange | positioned the metal plate on the outer peripheral part of a planar spiral coil. FIG. 5 is a block diagram of a wireless power transmission system according to a second embodiment. The figure which shows the winding-up part which moves a metal plate by winding-up of a connecting wire. The perspective view which shows the example which arrange | positions a metal plate in the hollow part of a planar spiral coil. FIG. 10 is a longitudinal sectional view of the configuration of FIG. The figure which shows the rotation part which moves a metal plate by arm rotation. The figure which shows the example of the film which printed the metal pattern. The figure which shows the structure which incorporated the power transmission apparatus in the display apparatus. FIG. 10 is a block diagram of a wireless power transmission system according to a fourth embodiment. 15 is a flowchart showing a procedure for adjusting the position of the metal plate in the system of FIG. FIG. 16 is a flowchart showing a modified example of the procedure of FIG. FIG. 9 is a block diagram of a wireless power transmission system according to a fifth embodiment. FIG. 10 is a block diagram of a wireless power transmission system according to a sixth embodiment.

  Hereinafter, the present embodiment will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 shows a wireless power transmission system according to the first embodiment.

  The wireless power transmission system includes a power transmission device (wireless power transmission device) 101 and a power reception device (wireless power reception device) 102.

  The power transmission apparatus 101 includes a first self-resonant coil 103, a metal plate 104, and a metal plate moving unit 105.

  The metal plate 104 is disposed so as to face a part of one end face (first end face) of both end faces of the first self-resonant coil 103. Here, when the coil is wound perpendicularly to the axis, a surface that passes through the end of the coil and is perpendicular to the axis and coincides with the inner region of the coil including the coil is defined as the end surface of the coil. (Or end face). For example, the metal plate 104 has an area smaller than the one end face (first end face). The metal plate 104 is a metal having an arbitrary shape. For example, it is composed of a copper plate or an aluminum plate.

  The metal plate moving unit 105 moves the metal plate 104 in a direction parallel to the one end face of the first self-resonant coil 103. That is, the metal plate moving unit 105 can change the position of the metal plate 104. Depending on the position of the metal plate 104, the resonance frequency of the first self-resonant coil 103 is made variable.

  The power receiving apparatus 102 includes a second self-resonant coil (receiving apparatus side coil) 106.

  The first self-resonant coil 103 and the second self-resonant coil 106 are coils that resonate at a predetermined frequency by self-inductance and self-capacitance. The first self-resonant coil 103 and the second self-resonant coil 106 are, for example, coils having n turns (n is an integer of 1 or more).

  The first self-resonant coil 103 and the second self-resonant coil 106 are not limited to a cylindrical shape. For example, a quadrangular prism shape, a spiral coil, or the like may be used.

  The first self-resonant coil 103 of the power transmission apparatus 101 receives supply of high-frequency power (energy) from a high-frequency generation circuit (not shown), and transmits a part of the high-frequency energy to the second self-resonant coil 106 by magnetic coupling. .

  More specifically, by supplying the first self-resonant coil 103 with high-frequency energy that matches the resonance frequency of the first and second self-resonant coils 103, 106, a part of the high-frequency energy is secondly reflected by magnetic resonance. It is transmitted to the self-resonant coil 106. By using magnetic resonance, high transmission efficiency is possible.

  In the power receiving apparatus 102, in addition to the second self-resonant coil 106, elements such as a rectifier circuit, an electronic circuit, and a rechargeable secondary battery are provided. The rectifier circuit converts the high-frequency energy received by the second self-resonant coil 106 into direct current. The electronic circuit operates using the output current generated by the rectifier circuit. The secondary battery is charged by the output current of the rectifier circuit.

  In the present embodiment, a self-resonant coil is used as a coil for power transmission and power reception. However, power transmission may be performed using magnetic coupling by a normal coil instead of magnetic resonance.

  Hereinafter, the reason why the resonance frequency is varied by the movement of the metal plate 104 will be described with reference to FIG. 2, FIG. 3, and FIG. That is, the principle of changing the resonance frequency will be described.

  FIG. 2 shows an example of magnetic field lines 203 generated when high frequency energy is supplied to the first self-resonant coil 103.

  The self-inductance of the first self-resonant coil 103 is L, and the self-capacitance is C. At this time, the resonance frequency of the first self-resonant coil 103 is expressed by the following equation.

この式から、自己インダクタンスL、または、自己キャパシタンスCを可変にできれば、共振周波数を可変にすることが可能である。

From this equation, if the self-inductance L or the self-capacitance C can be made variable, the resonance frequency can be made variable.

  FIG. 3 shows an example in which the metal plate 304 is arranged so as to block the magnetic field lines 303 of the first self-resonant coil 103.

  At this time, an eddy current is generated in the metal plate so as to cancel the magnetic field around the metal plate 104, and the inductance of the first self-resonant coil 103 is reduced. As a result, the resonance frequency of the first self-resonant coil 103 is increased.

  FIG. 4 shows an example in which the metal plate 104 is disposed on the outer peripheral portion of the end face of the first self-resonant coil 103.

  At this time, since the metal plate 104 does not block the lines of magnetic force, the inductance of the first self-resonant coil 103 does not decrease. On the other hand, the capacitance between the coils increases due to capacitive coupling between the metal plate 104 and the coil. That is, the capacitance between the metal plate 104 and the coil 103 is added to the capacitance originally existing between the wires of the coil. This increase in line capacitance is equivalent to an increase in self-capacitance. As a result, the resonance frequency of the first self-resonant coil 103 is lowered.

  Thus, by adjusting the position of the metal plate, the resonance frequency of the first self-resonant coil 103 can be changed to be higher or lower.

  In the present embodiment, since the position of the metal plate 104 is made variable by the metal plate moving unit 105, the resonance frequency of the first self-resonant coil 103 can be increased or decreased.

  Here, it is preferable that the movement of the metal plate 104 can be performed at least in the range from the center of the one end face of the first self-resonant coil 103 to the outer peripheral portion of the one end face.

  FIG. 5 shows a state in which the metal plate 104 is moved to the center of the end face of the first self-resonant coil 103.

  FIG. 6 shows a state in which the metal plate 104 is moved on the outer periphery of the first self-resonant coil 103.

  By moving the metal plate in such a range, the maximum self-inductance can be reduced and the maximum self-capacitance can be increased. That is, the maximum resonance frequency variable width can be obtained.

  In this embodiment, the position of the metal plate 104 is variable, but the metal plate 104 can be fixedly arranged at a position where a desired resonance frequency can be obtained without providing the metal plate moving unit 105. It is.

  Further, in the present embodiment, the metal plate 104 is disposed close to the end surface on the side where the second self-resonant coil 106 exists among the both end surfaces of the first self-resonant coil 103, but is disposed close to the end surface on the opposite side. It is also possible to make it.

  As long as the magnetic field lines pass therethrough, a metal plate may be disposed outside the vicinity of both end faces of the first self-resonant coil 103. Also in this case, a part of the lines of magnetic force are blocked by the metal plate, and the inductance can be changed.

  In the present embodiment, an example in which a metal plate is arranged with respect to the first self-resonant coil 103 on the transmission side is shown, but a metal plate can be similarly arranged on the second self-resonant coil on the reception side. is there. Thereby, the resonant frequency of the second self-resonant coil can be made variable. Alternatively, a metal plate may be disposed in both the first self-resonant coil and the second self-resonant coil, and the resonance frequency of each coil may be made variable.

  In the present embodiment, an example in which power transmission (energy transmission) is performed between the coils has been described, but a signal (modulation signal) for wireless communication may be transmitted between the coils.

  As described above, according to the present embodiment, the metal plate 104 is disposed so as to block a part of the lines of magnetic force generated by the first self-resonant coil 103, and the self-inductance of the first self-resonant coil 103 is adjusted. The resonance frequency of the first self-resonant coil 103 can be set to an arbitrary value.

  In addition, since the metal plate 104 is disposed so as to face one end surface of the first self-resonant coil 103, the self-inductance can be decreased and the self-capacitance can be increased at the same time. In addition, an increase in the thickness of the power transmission device can be minimized, that is, the thickness can be reduced.

  Further, according to the present embodiment, by providing the metal plate moving part that moves the position of the metal plate, the resonance frequency of the first self-resonant coil can be dynamically increased or decreased. .

  Further, according to the present embodiment, it is possible to extremely reduce the deterioration of transmission efficiency as compared with the conventional case. That is, the eddy current generated in the metal plate deteriorates the transmission efficiency, but since the metal plate 104 is coupled to the self-resonant coil 103 through the space, the influence of the parasitic resistance is small. Therefore, the degradation of transmission efficiency can be reduced as compared with the case where a capacitor is connected to a coil as in the prior art.

(Second embodiment)
FIG. 7 shows a wireless power transmission system according to the second embodiment. Elements having the same names as those in FIG.

  Unlike the first embodiment, the metal plate 104 is disposed so as to face a part of the side surface of the first self-resonant coil 103 (for example, in parallel). In such an arrangement, the magnetic field lines are not blocked or hardly blocked by the metal plate 104. Therefore, the capacitance between the metal plate 104 and the first self-resonant coil 103 is a dominant factor that determines the resonance frequency of the first self-resonant coil 103.

  When reducing the resonance frequency, the metal plate moving unit 105 moves the metal plate so as to increase the capacity to be formed. Specifically, the opposing area of the metal plate 104 and the first self-resonant coil 103 is increased. Conversely, when the resonance frequency is increased, the resonance area is moved so that the opposing area becomes smaller.

(Third embodiment)
In this embodiment, the structure of a metal plate moving part is shown concretely.

  FIG. 8 shows a first configuration example of the metal plate moving unit.

  The metal plate moving unit in FIG. 8 includes connecting lines 111 and 113 and winding units 112 and 114.

  The connection lines 111 and 113 are made of an insulator such as thread or nylon, or a dielectric. One end of the connection lines 111 and 113 is fixed (connected) to the metal plate 104.

  The winding portions 112 and 114 are coupled to the other ends of the connection lines 111 and 113, and are configured to be able to wind the connection lines 111 and 113 by a driving means such as a motor.

  The winding portions 112 and 114 are arranged so as to face each other with the coil 103 interposed therebetween. The metal plate 104 can move linearly between the winding portions 112 and 114.

  The winding part 112 winds the connection wire 111, whereby the metal plate 104 can be moved to the winding part 112 side. When the winding unit 114 winds the connection wire 113, the metal plate 104 can be moved to the winding unit 114 side.

  In the configuration of FIG. 8, the variable amount of the resonance frequency can be changed to a large or small value by the amount of winding of the connection lines 111 and 113. Therefore, the variable amount of the resonance frequency can be easily increased or decreased.

  Although the configuration example of FIG. 8 includes two winding portions, only one winding portion may be provided.

  FIG. 8 shows the case where a circular spiral coil is used as the first self-resonant coil, but FIGS. 9 and 10 show the case where a directional spiral coil is used. FIG. 9 is a perspective view, and FIG. 10 is a cross-sectional view taken along line AA.

  In this example, the metal plate 104 is disposed in the hollow portion (inside the coil) of the first self-resonant coil (planar spiral coil) 103a. This makes it possible to make the portion including the planar spiral coil and the metal plate that require a large area extremely thin. The winding portions 112 and 114 are arranged at the same height as the first self-resonant coil 103a. Thereby, the whole apparatus can be thinned.

  In the configuration of FIG. 9, since the metal plate 104 cannot move onto the outermost periphery of the first self-resonant coil 103a, the amount by which the self-capacitance can be adjusted is reduced. Therefore, the adjustment of the self-inductance is dominant in changing the resonance frequency of the first self-resonant coil 103a.

  FIG. 11 shows a second configuration example of the metal plate moving unit.

  The metal plate moving unit in FIG. 11 includes a connecting arm 121, a rotary bearing 122, and a rotating unit 123.

  One end of the connection arm 121 is fixed to the metal plate 104.

  A rotary bearing 122 is formed on the rotary part 123. The other end of the connection arm 121 is fitted to the rotary bearing 122.

  The rotating part 123 moves the connecting arm 121 in the direction of the arrow in the drawing, that is, in the direction parallel to the coil end surface, with the other end of the connecting arm 121 as a fulcrum. Thereby, the metal plate 103 is moved in an arc shape around the other end (rotary bearing) of the connection arm 121.

  In the configuration of FIG. 9, since the magnitude of the variable amount of the resonance frequency can be changed depending on the amount of rotation, the variable amount of the resonant frequency can be easily increased or decreased.

  FIG. 12 shows a third configuration example of the metal plate moving unit.

  In this example, the winding units 131 and 132 wind up the film 133 from both ends of the film 133. Metal patterns 104a, 104b, and 104c are printed on the film 133. The illustration of the first self-resonant coil is omitted for simplicity.

  The metal patterns 104a, 104b, 104c have different shapes. It is possible to freely change the resonance frequency of the self-resonant coil by selecting a metal pattern having an optimal shape and adjusting the position of the selected metal pattern by winding the film.

  FIG. 13 shows an arrangement example of winding portions that can reduce the thickness of the housing of the display device when the power transmission device is incorporated into the display device. Here, an example in which a power transmission device including the configuration of FIG. 9 is incorporated into a display device is shown.

  A power transmission device is incorporated in the housing 142 of the display device 141. The display device 141 is, for example, a liquid crystal display device.

  A first self-resonant coil (planar spiral coil) 103a and a metal plate 104 are disposed on the back side of the display unit 143 of the display device 141. The planar spiral coil 103a and the metal plate 104 are arranged at the same height (in the same plane).

  The winding portions 112 and 114 are arranged on the outer peripheral portion in the housing 142. The outer peripheral portion in the housing 142 is a portion in which the thickness can be secured most in the housing 142 because the display portion 143 and the coil 103a are not present. The thickness of the casing 142 can be reduced by not overlapping the winding portions 112 and 114 that require thickness with the display portion 143.

(Fourth embodiment)
FIG. 14 shows a wireless power transmission system according to the fourth embodiment.

  The wireless power transmission system includes a power transmission device 201 and a power reception device 202 to which power (energy) is supplied from the power transmission device 201. Each of the power transmission apparatus 201 and the power reception apparatus 202 has a wireless communication function.

  The power transmission apparatus 201 includes a first self-resonant coil 103, a metal plate 104, a metal plate moving unit 105, a control circuit 208, a wireless circuit 207, and an antenna 206.

  The power receiving apparatus 202 includes a second self-resonant coil 106, a received power measuring apparatus 210, a control circuit 211, a radio circuit 212, and an antenna 213.

  Since the first self-resonant coil 103, the metal plate 104, the metal plate moving unit 105, and the second self-resonant coil 106 are the same as those in the first embodiment (see FIG. 1), they are assigned the same reference numerals and overlap. Description is omitted.

  The present embodiment is characterized in that the position of the metal plate 104 in the power transmitting apparatus 201 is adjusted so that the received power in the power receiving apparatus 202 is maximized or satisfies a desired value.

  FIG. 15 shows a flow of operations for adjusting the position of the metal plate 104 to a position where high-efficiency transmission is possible in the wireless power transmission system of FIG.

(Step S101) The position adjustment mode is entered by exchanging information between the control circuit 208 of the power transmitting apparatus 201 and the control circuit 211 of the power receiving apparatus 202.

(Step S102) The metal plate moving unit 105 moves the metal plate 104 in accordance with an instruction from the control circuit 208.

(Step S103) A high frequency energy generation circuit (not shown) supplies high frequency energy of a predetermined frequency to the first self-resonant coil 103 in accordance with an instruction from the control circuit 208.

  The second self-resonant coil 106 receives high-frequency energy by magnetic coupling with the first self-resonant coil 103. The received power measuring unit 210 measures high-frequency energy (received power) received by the second self-resonant coil 106.

  The control circuit 211 of the power receiving apparatus 202 transmits the measured received power value to the power transmitting apparatus 201 via the wireless circuit 212 and the antenna 213.

  In the power transmission apparatus 201, the measured received power value is received by the control circuit 208 via the antenna 206 and the wireless circuit 207.

(Step S104) The control circuit 208 of the power transmission apparatus 201 determines whether all the metal plate position candidates have been tried. When all the position candidates have not been tried yet, the process returns to step S102, and the metal plate is moved to a position that has not been tried yet. When all the position candidates have been tried, the process proceeds to step S105.

(Step S105) The control circuit 208 of the power transmitting apparatus 201 selects the position of the metal plate 104 that maximizes the received power, and instructs the metal plate moving unit 105 to move the metal plate 104 to the selected position. The metal plate moving unit 105 moves the metal plate 104 to the instructed position.

(Step S106) The control circuit 208 of the power transmission apparatus 201 determines the start of power transmission, and instructs a high-frequency energy generation circuit (not shown) to start power transmission. The high frequency energy generation circuit that has received an instruction to start power transmission starts power transmission by supplying high frequency energy to the first self-resonant coil 103. In power reception device 202, for example, a secondary battery (not shown) is charged with the transmitted power.

  High power reception power can be obtained by starting the power transmission through the above steps. In other words, power transmission is possible with the resonance frequency of the first self-resonant coil 103 optimized.

  The processes in steps S104 and S105 may be changed as follows.

  That is, in step S104, it is determined whether the received power satisfies a desired value. If the desired value is not satisfied, the process returns to step S102 to try another position candidate. When the desired value is satisfied or when all the position candidates have been tried, the process proceeds to step S105.

  In step S105, when the desired value is satisfied, the metal plate 104 is moved to a position where the desired value is satisfied, and when the desired value is not satisfied, the metal plate 104 is moved to a position where the received power value is the highest. Let

  Here, three examples of how to determine the position candidates for moving the metal plate in step S102 are shown as the first method, the second method, and the third method.

[First Method] The position of the metal plate is sequentially moved from the position where the self-capacitance value of the first self-resonant coil is the largest toward the position where the self-inductance value is the smallest.

  If the position of the metal plate is moved in this manner, the distance that the metal plate moves can be shortened, which is effective when the position of the metal plate is to be adjusted in a short time. Note that the metal plate may be sequentially moved from the position where the self-inductance value is smallest to the position where the self-capacitance value is largest.

  In step S104 in the case of using the first method, if the received power is measured with all the metal plate position candidates, the process proceeds to step S105, and if not, the process returns to step S102.

[Second Method] The metal plate is moved with reference to the position of the initial setting value. Here, the initial set value is the position of the metal plate where the resonance frequency is optimized when there is no influence from a nearby desk or the like.

  First, the metal plate is set to the position of the initial setting value, and the received power is measured. Next, the received power is measured with two position candidates: a case where the metal plate is moved to a position candidate where the resonance frequency is high, and a case where the metal plate is moved to a position candidate where the resonance frequency is low. .

  In step S104, the received power measured at these three positions (initial setting value position and two position candidates) is compared.

  When the received power measured at the position of the initial setting value is the maximum value among the three positions, the process proceeds to step S105, and the position of the metal plate is determined as the position of the initial setting value.

  If the received power is maximum when the metal plate is moved to a position candidate with a higher resonance frequency among the three positions, the process returns to step S102, and the metal plate is moved to a position candidate with a higher resonance frequency. Move. In step S104 again, the received power at the candidate position after movement is compared with the received power at the previous candidate position. When the received power at the previous candidate position is larger, the process proceeds to step S105, and the position of the metal plate is determined as the previous candidate position.

  If the received power is the maximum when the metal plate is moved to a position candidate with a lower resonance frequency among the three positions, the process returns to step S102, and the metal plate is placed on the position candidate with a lower resonance frequency. Move. Then, in step S104, the received power at the candidate position after movement is compared with the received power at the previous candidate position. When the received power at the previous candidate position is larger, the process proceeds to step S105, and the position of the metal plate is determined as the previous candidate position.

[Third Method] The position of the metal plate is moved with reference to the position used for power transmission in the past. In the second method, the position of the initial setting value is used as a reference. However, in the third method, the only difference is that the position used for power transmission in the past is used as a reference. Others are the same. The position used for power transmission in the past may be the position used for power transmission one time before, for example, or may be the position determined most frequently in the past.

  FIG. 16 shows a modification example of the operation flow of FIG. This operation flow is characterized in that the position of the metal plate is moved during power transmission. For example, when the arrangement state of a desk or the like in the vicinity of the system changes, the position of the metal plate capable of high-efficiency power transmission can also change. In this case, by moving the position of the metal plate according to this flow, high-efficiency transmission is possible regardless of the change in the arrangement state.

  In this operation flow, steps S107 and S108 are newly added to the flow of FIG. Hereinafter, the description will be focused on the difference from the operation flow shown in FIG.

  In step S107, the received power measuring unit 210 of the power receiving apparatus 202 measures the received power after a lapse of a certain time from the start of power transmission. The measured value of the received power is transmitted to the control circuit 208 of the power transmission apparatus 201.

  In step S108, the control circuit 208 of the power transmission apparatus 201 determines whether or not the position of the metal plate 104 needs to be readjusted. This is determined based on whether the measured received power is increased, the same, or decreased compared to the received power when the position is determined in step S105 performed immediately before. Here, the same means that the received power when the position is determined falls within a certain range (error range). An increase means an increase beyond the certain range, and a decrease means a decrease below the certain range.

  When the measured received power is the same as the received power when the position was determined immediately before, it is determined that readjustment of the position of the metal plate is not necessary. In this case, the process returns to step S106 and power transmission is started again.

  When the measured received power decreases compared to the received power when the position was determined immediately before, it is determined that the metal plate position needs to be readjusted. In this case, the process returns to step S101 and proceeds to the position adjustment mode.

  When the measured received power increases compared to the received power when the position is determined immediately before, two methods are possible.

  The first method determines that it is not necessary to readjust the position of the metal plate because large received power has been obtained so far. In this case, the process returns to step S106 to start power transmission.

  The second method decides to readjust the position of the metal plate because there is a possibility that a larger received power may be obtained due to a change in some situation. In this case, the process returns to step S101 and proceeds to the position adjustment mode.

  As described above, even when the position of the metal plate capable of high-efficiency power transmission is changed due to a change in some situation, the operation of this flow makes it possible to readjust the position of the metal plate and perform high-efficiency transmission.

  In the present embodiment, the case where the position of the metal plate is determined so as to maximize the received power has been described. However, the position of the metal plate may be determined using transmission efficiency as an evaluation function.

  The transmission efficiency is the ratio of the received power at the second self-resonant coil to the transmission power transmitted from the first self-resonant coil. In this case, the control circuit on the power transmission device side may calculate the transmission efficiency by dividing the value of the reception power acquired from the power reception device by the value of the transmission power.

(Fifth embodiment)
FIG. 17 shows a wireless power transmission system according to the fifth embodiment.

  This system is characterized in that a metal plate 304 and a metal plate moving unit 305 are arranged on the power receiving apparatus 302 side. The configurations of the metal plate 304 and the metal moving unit 305 are the same as those described in the previous embodiments. The power transmission device 301 is not provided with a metal plate and a metal plate moving unit.

  In the wireless power transmission system of FIG. 17, the flow of operation for adjusting the position of the metal plate 304 to a position where high-efficiency transmission is possible is basically the same as in FIG. 15 or FIG. The only difference is that the movement and position determination of the metal plate performed in steps S102 and S104 is performed on the power receiving apparatus 302 side. Therefore, the flow of the operation is self-explanatory and description thereof is omitted.

  As described above, according to the present embodiment, even when a metal plate is disposed on the power receiving device side, the resonance frequency of the second self-resonant coil is appropriately adjusted, and highly efficient power transmission is possible.

(Sixth embodiment)
FIG. 18 shows a wireless power transmission system according to the sixth embodiment.

  This system is characterized in that a metal plate and a metal plate moving unit are arranged in both the power transmission apparatus 201 and the power reception apparatus 302, respectively. The rest is the same as the previous embodiments.

  In the wireless power transmission system of FIG. 18, the flow of operation for adjusting the positions of the metal plates 104 and 304 to a position where high-efficiency transmission is possible basically corresponds to a combination of the fourth and fifth embodiments.

  That is, first, one of the metal plates 104 and 304 is fixed at a predetermined position, and the position of the other metal plate is determined according to the operation flow of FIG.

  Next, the other metal plate is fixed at the determined position, and the position of the one metal plate is determined according to the operation flow of FIG.

  As described above, according to the present embodiment, by arranging the metal plate on both the power receiving device and the power transmitting device, the resonance frequency of each self-resonant coil can be adjusted at the same time, and highly efficient power transmission becomes possible.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

Claims (14)

A coil that receives a supply of high-frequency energy and transmits the high-frequency energy to the receiver-side coil by magnetic coupling;
A metal plate disposed so as to face a part of the first end face which is one end face of both end faces of the coil;
A wireless power transmission device comprising: 2. The wireless power transmission device according to claim 1, wherein the metal plate has a smaller area than the first end face. 2. The wireless power transmission device according to claim 1, further comprising a metal plate moving unit that moves the position of the metal plate in parallel to the first end face. 4. The wireless power transmission device according to claim 3, wherein the metal plate moving unit moves the metal plate in a range from a center of the first end surface to an outer peripheral portion of the first end surface. The metal plate moving part is
A connection line having one end connected to the metal plate;
4. The wireless power transmission device according to claim 3, further comprising: a winding unit that winds the connection line through the other end of the connection line. The metal plate moving part is
An arm having one end connected to the metal plate;
4. The wireless power transmission device according to claim 3, further comprising: a rotating unit that rotates the arm in a direction parallel to the first end surface via the other end of the arm. The coil is a hollow coil having a hollow portion,
2. The wireless power transmission device according to claim 1, wherein the metal plate is disposed in a hollow portion of the coil. Further comprising a film,
The metal plate is a metal pattern printed on a film,
4. The wireless power transmission device according to claim 3, wherein the metal plate moving unit moves the metal pattern by winding the film. 9. The wireless power transmission device according to claim 8, wherein a plurality of metal patterns having different shapes are printed on the film. A coil that receives a supply of high-frequency energy and transmits the high-frequency energy to the receiver-side coil by magnetic coupling;
A metal plate disposed opposite to a part of the side surface of the coil;
A wireless power transmission device comprising: 11. The wireless power transmission device according to claim 10, further comprising a metal plate moving unit that moves the metal plate in a direction parallel to a side surface of the coil. A coil that receives high-frequency energy from the transmitter coil by magnetic coupling;
A metal plate disposed so as to face a part of the first end face which is one end face of both end faces of the coil;
A wireless power receiving apparatus. 13. The wireless power receiving device according to claim 12, wherein the metal plate has an area smaller than the first end surface. 13. The wireless power receiving apparatus according to claim 12, further comprising a metal plate moving unit that moves the position of the metal plate in parallel with the first end face.

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