JP5804303B2 - Power transmission equipment - Google Patents

Description

  The present invention relates to a power transmission device, and more particularly to a power transmission device that wirelessly transmits power from a power transmission device to a power reception device.

  As a wireless power transmission method, for example, as in Patent Document 1, a method of transmitting power from a primary coil on the power transmission unit side to a secondary coil on the load unit side using magnetic field coupling is generally used. Further, for example, as in Patent Documents 1 to 3, there is known a method (electric field coupling method) in which electric power is transmitted from a coupling electrode on the power transmission unit side to a coupling electrode on the load unit side using an electrostatic field.

Japanese Patent Laid-Open No. 11-40206 Special table 2009-531009 JP 2009-296857 A JP 2009-89520 A

  However, in the magnetic field coupling method, since the magnitude of the magnetic flux passing through the coil greatly affects the electromotive force, high positional accuracy of the primary coil and the secondary coil is required, and it is difficult to reduce the size of the coil.

  In addition, the electric field coupling method uses an electrostatic field between the coupling electrodes, so that the positional accuracy of each coupling electrode can be relaxed and the coupling electrode can be downsized. Since a principle completely different from the method is adopted, if one power transmission device is adapted to any method, the circuit configuration may be complicated.

  Therefore, a main object of the present invention is to provide a power transmission device that can cope with both the magnetic field coupling method and the electric field coupling method while suppressing the complexity of the circuit configuration.

A power transmission device according to the present invention (10: reference numeral corresponding to the embodiment; the same applies hereinafter) is a voltage booster in cooperation with a low voltage side winding (L1) connected to an AC power source (12 to 14) and a low voltage side coil. High-voltage side winding (L2) forming the transformer (16), one end connected to one end of the high-voltage side winding, a coil (L3) for performing magnetic field coupling type power transmission, one of the high-voltage side winding The first electrode (E5) connected to the end, the second electrode (E1 to E4, E11) that performs electric field coupling type power transmission in cooperation with the first electrode, the other end of the coil and the second electrode on the high voltage side Based on the first switch (SW1) selectively connected to the other end of the winding and the impedance on the output side of the AC power supply, or based on the specification information of the power receiving device, the power transmission method of the power receiving device Control means (S1, S11 to S15, S37 to S41, S47) for identifying and controlling the connection mode of the first switch is provided.

  Preferably, the control means includes first request means (S13 to S15, S39 to S41) for requesting the first switch to select the other end of the coil when the power transmission method of the power receiving device is a magnetic field coupling method, and the power receiving device. When the power transmission method is the electric field coupling method, second request means (S1, S13, S39, S47) for requesting the first switch to select the second electrode is included.

  Preferably, the first electrode and the second electrode correspond to a large electrode and a small electrode, respectively.

  Preferably, the second electrode includes a plurality of partial electrodes (E1 to E4), and further includes a second switch (24) for selectively connecting the plurality of partial electrodes to the first switch.

  Preferably, adjustment means (S19, S23, S45, S51) for adjusting the transformation ratio of the step-up transformer so as to conform to the power transmission method of the power receiving apparatus is further provided.

  Preferably, detecting means (S3 to S9, S35) for detecting the position of the power receiving device, and first moving means (S17) for moving the coil to the position detected by the detecting means when the power receiving method of the power receiving device is a magnetic field coupling method. , S43), and second moving means (S21, S49) for moving the second electrode to the position detected by the detecting means when the power receiving method of the power receiving device is the electric field coupling method.

  The other end of the high-voltage side winding is connected to one of the other end of the coil and the second electrode by the first switch, and the connection mode of the first switch is the power receiving device placed on the placement surface of the housing The power transmission method is identified and controlled.

  Accordingly, the first electrode functions as a ground electrode when the magnetic field coupling method is selected, and functions as a part of the power transmission electrode when the electric field coupling method is selected. By sharing the first electrode in this way, it is possible to cope with both the magnetic field coupling method and the electric field coupling method while suppressing the complexity of the circuit configuration.

  The above object, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

It is a block diagram which shows the structure of one Example of this invention. (A) is an illustration figure which shows an example of the state which looked at the power transmission apparatus shown in FIG. 1 from the top, (B) is an illustration figure which shows an example of the state which looked at the power transmission apparatus shown in FIG. 1 from the side. It is an illustration figure which shows an example of operation | movement of a coil unit when the power receiving apparatus which employ | adopts a magnetic field coupling system is mounted in the power transmission apparatus. It is an illustration figure which shows an example of operation | movement of an electrode unit when the power receiving apparatus which employ | adopts an electric field coupling system is mounted in the power transmission apparatus. It is a flowchart which shows a part of operation | movement of the control circuit provided in the power transmission apparatus shown in FIG. It is a block diagram which shows the structure of the other Example of this invention. (A) is an illustration figure which shows an example of the state which looked at the power transmission apparatus shown in FIG. 6 from the top, (B) is an illustration figure which shows an example of the state which looked at the power transmission apparatus shown in FIG. 6 from the side. It is an illustration figure which shows an example of operation | movement of a coil unit when the power receiving apparatus which employ | adopts a magnetic field coupling system is mounted in the power transmission apparatus. It is an illustration figure which shows an example of operation | movement of an electrode unit when the power receiving apparatus which employ | adopts an electric field coupling system is mounted in the power transmission apparatus. It is a flowchart which shows a part of operation | movement of the control circuit provided in the power transmission apparatus shown in FIG.

  Referring to FIG. 1, the power transmission system of this embodiment includes a power transmission device 10 that supports both the magnetic field coupling method and the electric field coupling method, a power receiving device 40 that supports the magnetic field coupling method, and a power reception device that supports the electric field coupling method. Device 60. The power transmission device 10 includes a rectangular parallelepiped housing HS1 illustrated in FIGS. Here, the one main surface and the other main surface of the housing HS1 correspond to the upper surface and the lower surface, respectively, and the power receiving devices 40 and 60 are alternatively placed on the one main surface of the housing HS1. The power transmission device 10 transmits power to the power receiving device 40 by the magnetic field coupling method when the power receiving device 40 is placed, and transmits power to the power receiving device 60 by the electric field coupling method when the power receiving device 60 is placed.

  In the power transmission device 10, the control circuit 14 gives a PWM signal to the drive circuit 12. The drive circuit 12 converts the DC voltage supplied from the DC power source Vcc into an AC voltage according to the PWM signal supplied from the control circuit 14. The frequency of the converted AC voltage matches the frequency of the PWM signal, and the level of the converted AC voltage depends on the duty ratio of the PWM signal.

  The converted AC voltage is applied to the primary winding L1 forming the step-up transformer 16, and the AC voltage boosted to a different voltage according to the transformation ratio is excited in the secondary winding L2 forming the step-up transformer 16. . One end of the secondary winding L2 is connected to one end of an induction coil L3 for magnetic field coupling provided in the coil unit 20, and is further connected to a passive electrode (large electrode) E5 for electric field coupling. The other end of the secondary winding L2 is connected to a common terminal T1 that forms a switch SW1. Branch terminals T2 and T3 forming switch SW1 are connected to the other end of induction coil L3 and switch group 24, respectively.

  Here, the switch SW1 switches the other end of the secondary winding L2 to either the other end of the induction coil L3 or the switch group 24, but the one end of the secondary winding L2 is switched to the induction coil L3. May be switched to either one of the first electrode and the passive electrode E5.

  The switch group 24 includes switches SW11 to SW14, and the electrode unit 22 includes active electrodes (small electrodes) E1 to E4. The branch terminal T3 is connected to the active electrode E1 through the switch SW11, is connected to the active electrode E2 through the switch SW12, is connected to the active electrode E3 through the switch SW13, and is connected to the active electrode E4 through the switch SW14. Connected.

  The common terminal T1 forming the switch SW1 is connected to the branch terminal T2 when the power receiving device 40 is placed on the housing HS1, and is connected to the branch terminal T3 when the power receiving device 60 is placed on the housing HS1. Is done.

  The switches SW11 to SW14 are alternatively turned on when the power receiving device 60 is placed on the housing HS1. Specifically, the switch SW11 is turned on when the power receiving device 60 is placed near the active electrode E1, and the switch SW12 is turned on when the power receiving device 60 is placed near the active electrode E2. Further, the switch SW13 is turned on when the power receiving device 60 is placed near the active electrode E3, and the switch SW14 is turned on when the power receiving device 60 is placed near the active electrode E4.

  At the stage of detecting the placement of the power receiving device 40 or 60 on the housing HS1, the common terminal T1 forming the switch SW1 is connected to the branch terminal T3, and the switches SW11 to SW14 are turned on cyclically and alternatively. Is done. When the power receiving device 40 or 60 is placed on the housing HS1, the impedance on the output side of the drive circuit 12 increases, and the impedance value is the same as when the power receiving device 40 is placed and when the power receiving device 60 is placed. It is different from the time. The settings of the switch SW1 and the switch group 24 are adjusted with reference to such impedance.

  As can be seen from FIGS. 2A to 2B, each of the active electrodes E1 to E4 and the passive electrode E5 is formed in a rectangular plate shape and is housed in the housing HS1. Moreover, the induction coil L3 is formed in a disk shape, and this is also housed in the housing HS1.

  Here, the areas of the main surfaces of the active electrodes E1 to E4 are common to each other and are significantly smaller than the area of the main surface of the passive electrode E5. Further, the area of the main surface of the passive electrode E5 is slightly smaller than the area of the main surface of the housing HS1. Further, the diameter of the circle forming the main surface of the induction coil L3 is slightly smaller than the short side of the rectangle forming the main surface of each of the active electrodes E1 to E4.

  Here, the areas of the active electrode and the passive electrode may be the same.

  If the area of the active electrode is smaller than the passive electrode, the switch SW1 is provided on the active electrode side (the other end of the secondary winding L2 is switched to either the other end of the induction coil L3 or the switch group 24). Compared with providing on the passive electrode side (switching one end of the secondary winding L2 to one end of the induction coil L3 or one of the passive electrodes E5), the high electric field of the active electrode affects the induction coil L3. It is preferable because it is difficult.

  The passive electrode E5 is provided at substantially the center in the height direction of the housing HS1 with the one main surface facing upward and the other main surface facing downward. The active electrodes E1 to E4 are provided on the upper side of the passive electrode E5 in such a posture that each one main surface faces upward and each other main surface faces downward. When viewed from above, the active electrodes E1 to E4 are arranged in a matrix.

  Further, the induction coil L3 is provided on the upper side of the passive electrode E5 in a posture in which one main surface faces upward and the other main surface faces downward. The distance from one main surface of induction coil L3 to one main surface of housing HS1 is smaller than the distance from one main surface of each of active electrodes E1 to E4 to one main surface of housing HS1. Similarly, the distance from the other main surface of induction coil L3 to one main surface of housing HS1 is also smaller than the distance from one main surface of each of active electrodes E1 to E4 to one main surface of housing HS1.

  The XY table 18 shown in FIG. 1 moves the coil unit 20 in the left-right direction (= horizontal direction) with the posture in which one main surface of the induction coil L3 always faces upward, and the one main surface of the active electrodes E1 to E4 is always upward. The electrode unit 22 is moved in the left-right direction with the posture facing the. When the power receiving device 40 employing the magnetic field coupling method is placed at the position shown in FIG. 3, the coil unit 20 is moved by the XY table 18 so that the induction coil L <b> 3 is disposed below the power receiving device 40. On the other hand, when the power receiving device 60 that employs the electric field coupling method is placed at the position shown in FIG. 4, any one of the active electrodes E1 to E4 is disposed below the power receiving device 40. The electrode unit 24 is moved by the XY table 18.

  The drive circuit 12, the control circuit 14, the step-up transformer 16, the switch SW1, and the switch group 24 are built in the power transmission module TM1.

  Returning to FIG. 1, the power receiving device 40 is provided with an induction coil L4 for magnetic field coupling. One end and the other end of induction coil L4 are connected to one end and the other end of primary winding L5 that form step-down transformer 42 together with secondary winding L6. Therefore, when an AC voltage is applied to the induction coil L3 of the power transmission device 10, an AC voltage corresponding to the AC voltage is excited in the induction coil L4, and an AC voltage indicating a voltage corresponding to the step-down ratio of the step-down transformer 42 is secondary. Excited by the coil L6.

  The rectifying / smoothing circuit 44 rectifies and smoothes the AC voltage excited by the secondary coil L6. The DC-DC converter 46 adjusts the level of the DC voltage generated thereby, and supplies the DC voltage having the adjusted level to the mobile device 50 integrated with the power receiving device 40.

  The power receiving device 60 is provided with an active electrode E6 and a passive electrode E7 for electric field coupling. The active electrode E6 and the passive electrode E7 are connected to one end and the other end of the primary winding L7 that form the step-down transformer 62 together with the secondary winding L8.

  Therefore, when an AC voltage is applied to any one of the active electrodes E1 to E4 and the passive electrode E5 provided in the power transmission device 10, the corresponding AC voltage is excited to the active electrode E6 and the passive electrode E7, Further, an AC voltage indicating a voltage corresponding to the step-down ratio of the step-down transformer 62 is excited in the secondary coil L8.

  The rectifying / smoothing circuit 64 rectifies and smoothes the AC voltage excited by the secondary coil L8. The DC-DC converter 66 adjusts the level of the DC voltage generated thereby, and supplies the DC voltage having the adjusted level to the mobile device 70 integrated with the power receiving device 60.

  The control circuit 14 executes processing according to the flowchart shown in FIG. 5 in order to selectively transmit power to the power receiving apparatuses 40 and 60.

  First, in step S1, the common terminal T1 of the switch SW1 is connected to the branch terminal T3 in order to set the power transmission method to the electric field coupling method. In step S3, the switch SW11 is turned on to validate the active electrode E1, and in step S5, the impedance on the output side of the drive circuit 12 is measured.

  In step S7, it is determined based on the measured impedance whether or not the power receiving device 40 or 60 is placed in the vicinity of the activated active electrode E1. If the determination result is NO, other active electrodes are alternatively enabled in step S9, and then the process returns to step S3. Therefore, as long as the determination result of step S7 is maintained NO, the active electrode to be activated is cyclically switched in the order of “E1” → “E2” → “E3” → “E4” → “E1” →. It is done.

  If the determination result in step S7 is YES, it is determined in steps S11 to S13 whether the power transmission method employed by the power receiving device mounted on the housing HS1 is the magnetic field coupling method or the electric field coupling method. In the determination, the impedance measured in step S5 is referred to.

  If the power receiving device mounted on the housing HS1 is the power receiving device 40 adopting the magnetic field coupling method, the process proceeds from step S13 to step S15, and the power transmission method is set to the magnetic field coupling method. Specifically, the common terminal T1 of the switch SW1 is connected to the branch terminal T2. In step S <b> 17, the XY table 18 is controlled to move the coil unit 20 to the lower part of the power receiving device 40. The coil unit 20, that is, the induction coil L <b> 3 is disposed at a position facing the induction coil L <b> 4 provided in the power receiving device 40.

  In step S19, the step-up ratio of the step-up transformer 18 is adjusted to a ratio for magnetic field coupling. Specifically, when the step-up transformer is constituted by a winding type transformer, a plurality of midpoint taps are provided in the primary winding or the secondary winding, and a method of switching the turn ratio or a piezoelectric transformer is used for the transformer. A method of adjusting the step-up ratio by changing the frequency of the applied AC voltage is conceivable. When the process of step S19 is completed, a PWM signal is given to the drive circuit 12 to start power transmission to the power receiving device 40.

  On the other hand, if the power receiving device mounted on the housing HS1 is the power receiving device 60 that adopts the electric field coupling method, the process proceeds to step S21, and the XY table 18 is controlled to place the electrode unit 22 below the power receiving device 60. Move to. The electrode unit 22 is disposed at a position where the activated active electrode faces the active electrode E <b> 6 of the power receiving device 60. In step S23, the step-up ratio of the step-up transformer 18 is adjusted to a ratio for electric field coupling. Specifically, when the step-up transformer is constituted by a winding type transformer, a plurality of midpoint taps are provided in the primary winding or the secondary winding, and a method of switching the turn ratio or a piezoelectric transformer is used for the transformer. A method of adjusting the step-up ratio by changing the frequency of the applied AC voltage is conceivable. When the process of step S23 is completed, a PWM signal is given to the drive circuit 12 to start power transmission to the power receiving device 60.

  As can be seen from the above description, the primary winding L1 forming the step-up transformer 16 is connected to the drive circuit 12 that generates an AC voltage. One end of the secondary winding L2 constituting the step-up transformer 16 is connected to one end of an induction coil L3 for magnetic field coupling, and further to a passive electrode E5 for electric field coupling. The active electrodes E1 to E4 realize electric field coupling type power transmission in cooperation with the passive electrode E5. The other end of the secondary winding L2 forming the step-up transformer 16 is connected to the induction coil L3 and the active electrodes E1 to E4 via the switch SW1. The control circuit 14 identifies the power transmission method of the power receiving device mounted on the mounting surface of the housing HS1 and controls the connection mode of the switch SW1 (S1, S11 to S15).

  Here, the step-up ratio of the step-up transformer 18 may be fixed without adjustment.

  In this way, the other end of the secondary winding L2 is connected to either the other end of the induction coil L3 or the passive electrode E5 by the switch SW1, and the connection mode of the switch SW1 is based on the power transmission method of the power receiving device. Identify and control.

  Accordingly, the passive electrode E5 functions as a ground electrode when the magnetic field coupling method is selected, and functions as a part of the power transmission electrode when the electric field coupling method is selected. By sharing the passive electrode E5 in this way, it is possible to cope with both the magnetic field coupling method and the electric field coupling method while suppressing the complexity of the circuit configuration.

  Referring to FIG. 6, in a power transmission system according to another embodiment, a part of the configuration of power transmission device 10 is different from power transmission device 10 shown in FIG. 1, and control circuit 14 replaces the flowchart shown in FIG. 6. Since it is the same as that of the above-mentioned Example except the point which performs the process according to the flowchart shown in FIG. 10, the overlapping description regarding the same structure is abbreviate | omitted as much as possible.

  According to FIG. 6, the switch group 24 is omitted, and the electrode unit 22 having a single active electrode E <b> 11 is replaced with the electrode unit 26. The branch terminal T3 of the switch SW1 is directly connected to the active electrode E11.

  With further reference to FIGS. 7A and 7B, the position sensor 28 includes a plurality of sensor elements PS1 to PS21 provided in a matrix on the back side of the upper surface of the housing HS1. The position on the housing HS1 where the power receiving device 40 or 60 is placed is detected based on the plurality of sensor elements PS1 to PS21.

  The antenna 30 corresponds to an antenna for communicating with the mobile device 50 or 70. The power transmission method adopted by the power receiving device 40 is recognized by the mobile device 50, and the power transmission method adopted by the power receiving device 60 is recognized by the mobile device 70. The recognized power transmission method is transferred from the mobile device 50 or 70 to the power transmission device 10 and given to the control circuit 14 via the antenna 30 and the communication circuit 32.

  As can be seen from FIGS. 7A to 7B, the active electrode E11 has the same shape and size as one of the active electrodes E1 to E4 described above, with one main surface facing upward and the other. The main surface is housed in the housing HS1 with the posture facing downward. However, the active electrode E11 is disposed at the same height as the induction coil L3. The power transmission module TM1 additionally includes a communication circuit 32.

  When the power receiving device 40 adopting the magnetic field coupling method is placed at the position shown in FIG. 8, the coil unit 20 is moved by the XY table 18 so that the induction coil L3 is disposed below the power receiving device 40. On the other hand, when the power receiving device 60 that employs the electric field coupling method is placed at the position shown in FIG. 9, the electrode unit 26 is placed on the XY table so that the active electrode E <b> 11 is disposed below the power receiving device 40. 18 is moved.

  The power transmission to the power receiving device 40 or 60 is executed according to the flowchart shown in FIG. In step S31, ID authentication is executed with a mobile device existing in the vicinity. In step S33, it is determined whether or not the authentication is successful. If the determination result is NO, the processes in steps S31 to S33 are repeated. When the determination result is updated from NO to YES, the process proceeds to step S35, and the placement position of the authenticated power receiving apparatus is detected based on the output of the position sensor 28. When the position detection is completed, it is determined in steps S39 to S41 whether the power transmission method employed by the power receiving device mounted on the housing HS1 is the magnetic field coupling method or the electric field coupling method. In the determination, the specification information acquired from the mobile device 50 or 70 at the time of ID authentication is referred to.

  If the power receiving device mounted on the housing HS1 is the power receiving device 40 adopting the magnetic field coupling method, the process proceeds from step S41 to step S43, and the power transmission method is set to the magnetic field coupling method. Specifically, the common terminal T1 of the switch SW1 is connected to the branch terminal T2. In step S45, the XY table 18 is controlled to move the coil unit 20 to the lower part of the power receiving device 40. The coil unit 20, that is, the induction coil L <b> 3 is disposed at a position facing the induction coil L <b> 4 provided in the power receiving device 40. In step S47, the step-up ratio of the step-up transformer 18 is adjusted to a ratio for magnetic field coupling. Specifically, when the step-up transformer is constituted by a winding type transformer, a plurality of midpoint taps are provided in the primary winding or the secondary winding, and a method of switching the turn ratio or a piezoelectric transformer is used for the transformer. A method of adjusting the step-up ratio by changing the frequency of the applied AC voltage is conceivable. When the process of step S47 is completed, a PWM signal is given to the drive circuit 12 to start power transmission to the power receiving device 40.

  On the other hand, if the power receiving device mounted on the housing HS1 is the power receiving device 60 adopting the electric field coupling method, the process proceeds from step S41 to step S49, and the power transmission method is set to the electric field coupling method. Specifically, the common terminal T1 of the switch SW1 is connected to the branch terminal T3. In step S51, the XY table 18 is controlled to move the electrode unit 26 to the lower part of the power receiving device 60. The electrode unit 22, that is, the active electrode E <b> 11 is disposed at a position facing the active electrode E <b> 6 provided in the power receiving device 60. In step S53, the step-up ratio of the step-up transformer 18 is adjusted to a ratio for electric field coupling. Specifically, when the step-up transformer is constituted by a winding type transformer, a plurality of midpoint taps are provided in the primary winding or the secondary winding, and a method of switching the turn ratio or a piezoelectric transformer is used for the transformer. A method of adjusting the step-up ratio by changing the frequency of the applied AC voltage is conceivable. When the process of step S53 is completed, a PWM signal is given to the drive circuit 12 to start power transmission to the power receiving device 60.

  Also in this embodiment, the primary winding L1 forming the step-up transformer 16 is connected to the drive circuit 12 that generates an AC voltage. One end of the secondary winding L2 constituting the step-up transformer 16 is connected to one end of an induction coil L3 for magnetic field coupling, and further to a passive electrode E5 for electric field coupling. The active electrode E11 cooperates with the passive electrode E5 to realize electric field coupling type power transmission. The other end of the secondary winding L2 forming the step-up transformer 16 is connected to the induction coil L3 and the active electrode E11 via the switch SW1. The control circuit 14 controls the connection mode of the switch SW1 by identifying the power transmission method of the power receiving device mounted on the mounting surface of the housing HS1 (S37 to S41, S47).

  Thus, the other end of the secondary winding L2 is connected to either the other end of the induction coil L3 or the passive electrode E11 by the switch SW1, and the connection mode of the switch SW1 is based on the power transmission method of the power receiving device. Identify and control.

  Accordingly, the passive electrode E5 functions as a ground electrode when the magnetic field coupling method is selected, and functions as a part of the power transmission electrode when the electric field coupling method is selected. By sharing the passive electrode E5 in this way, it is possible to cope with both the magnetic field coupling method and the electric field coupling method while suppressing the complexity of the circuit configuration.

DESCRIPTION OF SYMBOLS 10 ... Power transmission apparatus 14 ... Control circuit 16 ... Boosting transformer 18 ... XY table 20 ... Coil unit 22, 26 ... Electrode unit 28 ... Position sensor 30 ... Antenna

Claims (6)

Low voltage side winding connected to AC power supply,
A high-voltage side winding that forms a step-up transformer in cooperation with the low-voltage side winding;
A coil that has one end connected to one end of the high-voltage side winding and performs magnetic field coupling type power transmission;
A first electrode connected to the one end of the high-voltage side winding;
A second electrode that performs electric field coupling type power transmission in cooperation with the first electrode;
A first switch that selectively connects one of the other end of the coil and the second electrode to the other end of the high-voltage side winding; and
Control means for controlling the connection mode of the first switch by identifying the power transmission method of the power receiving device based on the impedance on the output side of the AC power supply or based on the specification information of the power receiving device. , Power transmission equipment.   The control means includes first request means for requesting the first switch to select the other end of the coil when the power transmission method of the power receiving device is a magnetic field coupling method, and the power transmission method of the power receiving device is an electric field coupling. The power transmission device according to claim 1, further comprising: a second request unit that requests the first switch to select the second electrode when the method is used.   The power transmission device according to claim 1, wherein an area of the first electrode is larger than an area of the second electrode. The second electrode includes a plurality of partial electrodes,
4. The power transmission device according to claim 1, further comprising a second switch that selectively connects the plurality of partial electrodes to the first switch. 5.   5. The power transmission device according to claim 1, further comprising an adjusting unit that adjusts a transformation ratio of the step-up transformer so as to conform to a power transmission method of the power receiving device. Detecting means for detecting the position of the power receiving device;
First moving means for moving the coil to a position detected by the detecting means when the power receiving system of the power receiving apparatus is a magnetic field coupling system; and the second electrode when the power receiving system of the power receiving apparatus is an electric field coupling system The power transmission device according to any one of claims 1 to 5, further comprising a second moving unit that moves a position to a position detected by the detecting unit.

Images