JP2014030329A - Noncontact power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noncontact power transmission device capable of performing bidirectional power transmission between a primary apparatus and a secondary apparatus in noncontact manner, while enhancing power transmission efficiency in any direction.SOLUTION: High frequency power is transmitted between a ground side apparatus 11 and a vehicle side apparatus 21 in noncontact manner, by magnetic field resonance of a primary resonator 13 provided in the ground side apparatus 11 and a secondary resonator 23 provided in the vehicle side apparatus 21. Impedance converters 31, 32 are provided on the common path EL3 of a charge path EL1 formed of a primary high frequency power supply 12, resonators 13, 23 and a secondary load 22, and a discharge path EL2 formed of a secondary high frequency power supply 27, the resonators 13, 23 and a primary load 14.

Description

  The present invention relates to a contactless power transmission device.

  2. Description of the Related Art Conventionally, as a non-contact power transmission device that does not use a power cord or a power transmission cable, for example, a device using magnetic field resonance is known. For example, the non-contact power transmission device of Patent Document 1 includes a primary side device having an AC power source and a primary side resonance coil to which AC power is input from the AC power source. The non-contact power transmission device is provided in a vehicle as a secondary side device, and includes a secondary side resonance coil capable of magnetic field resonance with a primary side resonance coil. Then, AC power is transmitted from the primary device to the vehicle by magnetic resonance between the primary resonance coil and the secondary resonance coil. The AC power is used for charging an in-vehicle battery provided in the vehicle.

JP 2009-106136 A

  Here, there is a case where the vehicle is required to be used as a power source, for example, an electric device other than the vehicle is driven using an in-vehicle battery. In order to meet this requirement, a non-contact power transmission device capable of bidirectional power transmission between the primary side device and the secondary side device is conceivable. In such a non-contact power transmission apparatus, there is a concern that the transmission efficiency may be reduced due to different power transmission paths.

  The present invention has been made in view of the above-described circumstances, and in a non-contact power transmission apparatus capable of performing non-contact bidirectional power transmission between a primary side device and a secondary side device, An object of the present invention is to provide a non-contact power transmission device capable of improving transmission efficiency even in direction power transmission.

  In order to achieve the above object, the invention according to claim 1 is directed to a primary device having a primary coil to which primary AC power is input, and the primary without contact from the primary coil. A secondary side device having a secondary side coil capable of receiving side AC power, wherein the secondary side coil is input with secondary side AC power, and the primary side coil is The secondary side AC power can be received from the secondary side coil in a non-contact manner, and the primary side AC power source that outputs the primary side AC power, the primary side coil, and the secondary side device On the first power transmission path formed by the provided secondary coil and the secondary load, the secondary AC power source that outputs the secondary AC power, the secondary coil, and the first coil Formed by the primary coil and the primary load provided in the secondary equipment On the on the second power transmission path is characterized by comprising an impedance converting unit for performing impedance conversion.

  According to this invention, since the impedance conversion unit is provided on both the first power transmission path and the second power transmission path, the impedance conversion is performed regardless of which power transmission path is used for power transmission. Is done. In this case, in any case where power transmission is performed using any power transmission path, the transmission efficiency can be improved in power transmission in any direction by performing impedance conversion so as to increase the transmission efficiency. .

  The invention according to claim 2 is characterized in that the impedance converter is provided on a common path of the first power transmission path and the second power transmission path. According to this invention, since the impedance converter is provided on the common path, it is not necessary to provide an impedance converter on each power transmission path. For this reason, simplification of a structure can be achieved.

  According to a third aspect of the present invention, there is provided a change unit that changes a constant of the impedance conversion unit when the state in which the primary AC power is input is switched to the state in which the secondary AC power is input. It is characterized by having. According to this invention, the optimum constant (high transmission efficiency can be obtained) of the impedance converter due to the switching from the state where the primary AC power is input to the state where the secondary AC power is input. Possible constants) may change. In this regard, according to the present invention, high transmission efficiency can be realized both before and after the switching by changing the constant of the impedance conversion unit based on the switching.

  According to a fourth aspect of the present invention, the primary side coil constitutes a primary side resonator, the secondary side coil constitutes a secondary side resonator, and the primary side load is input. The impedance and the input impedance of the secondary side load are the same, the primary side resonator and the secondary side resonator have the same shape, and are provided in the primary side device as the impedance converter. The primary side impedance conversion unit and the secondary side impedance conversion unit provided in the secondary side device, and the changing unit is connected to the primary side impedance conversion unit and the secondary side impedance conversion unit. A constant set in the primary side impedance converter in the state where the primary side AC power is input is set in the secondary side impedance converter, and the primary side impedance converter and the secondary side are set. Wherein the primary-side AC power to the impedance conversion unit sets the set constants in the secondary side impedance converter in a state that is input to the primary side impedance converter. According to this invention, the impedance conversion part is provided in both the primary side apparatus and the secondary side apparatus. Then, when switching from the state where the primary AC power is input to the state where the secondary AC power is input, the constant of the primary impedance converter and the constant of the secondary impedance converter are switched. . Specifically, the constants of the secondary side impedance conversion unit are set to the primary side impedance conversion unit in a state where the primary side AC power is input to the primary side impedance conversion unit and the secondary side impedance conversion unit. The constant of the primary side impedance conversion unit is changed to the constant set in the secondary side impedance conversion unit in a state where the primary side AC power is input to the primary side impedance conversion unit and the secondary side impedance conversion unit. Change to Thereby, even if it is a case where it switches from the state in which primary side alternating current power is input to the state in which secondary side alternating current power is input, a state with high transmission efficiency can be maintained. Further, in this case, since it is not necessary to perform processing such as calculating a constant in a state where secondary AC power is input, it is possible to easily change the constant of each impedance converter.

  The “same shape” means that at least the capacitance and the inductance are the same in the primary side resonator and the secondary side resonator. When an external load is connected to the primary load, the input impedance of the primary load includes the impedance of the external load.

  According to the present invention, it is possible to improve transmission efficiency in power transmission in any direction.

The block diagram which shows the electrical constitution of the non-contact electric power transmission apparatus which concerns on this invention. The circuit diagram which shows the non-contact electric power transmission apparatus in which the charge path | route was formed. The circuit diagram which shows the non-contact electric power transmission apparatus in which the discharge path | route was formed. The flowchart which shows the charging / discharging start process performed with a power supply side controller. The circuit diagram which shows another example of a non-contact electric power transmission apparatus.

Hereinafter, a non-contact power transmission apparatus (non-contact power transmission system) according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, the non-contact power transmission apparatus 10 includes a ground side device 11 provided on the ground and a vehicle side device 21 mounted on the vehicle. The ground side device 11 corresponds to the primary side device (power transmission device), and the vehicle side device 21 corresponds to the secondary side device (power receiving device).

  The non-contact power transmission device 10 includes a first power transmission path EL1 as a path for performing power transmission from the ground side device 11 to the vehicle side device 21, and a path for performing power transmission from the vehicle side device 21 to the ground side device 11. As a second power transmission path EL2.

  First, the configuration related to the first power transmission path EL1 will be described. The ground-side device 11 includes a primary-side high-frequency power source 12 (primary-side AC power source) that can output high-frequency power (AC power) having a predetermined frequency. ing. The primary side high frequency power source 12 is configured to convert low frequency power input from a system power source as infrastructure into high frequency power and to output the converted high frequency power. Specifically, the primary side high-frequency power source 12 includes a rectifier that rectifies low-frequency power of the system power source into DC power, and a DC / DC converter that converts the voltage of the DC power rectified by the rectifier into voltages of different magnitudes. It has. Further, the primary-side high-frequency power source 12 includes a DC / RF converter that generates high-frequency power using DC power output from the DC / DC converter.

  The high-frequency power (primary AC power) output from the primary-side high-frequency power source 12 is transmitted to the vehicle-side device 21 in a non-contact manner and input to the secondary-side load 22 provided in the vehicle-side device 21. Specifically, the non-contact power transmission device 10 is configured to transmit power between the ground side device 11 and the vehicle side device 21, and the primary side resonator 13 (primary side resonance) provided in the ground side device 11. And a secondary side resonator 23 (secondary side resonator) provided in the vehicle-side device 21.

  The primary side resonator 13 and the secondary side resonator 23 are configured to be capable of magnetic field resonance. Specifically, as shown in FIG. 2, the primary side resonator 13 includes a primary side coil 13a and a primary side capacitor 13b connected in parallel. The secondary side resonator 23 includes a secondary side coil 23a and a secondary side capacitor 23b connected in parallel. Both resonance frequencies are set to be the same.

  According to this configuration, when high frequency power is input to the primary side resonator 13, the primary side resonator 13 (primary side coil 13a) and the secondary side resonator 23 (secondary side coil 23a) are connected. Magnetic field resonance. As a result, the secondary resonator 23 receives a part of the energy of the primary resonator 13. That is, the secondary resonator 23 receives high frequency power from the primary resonator 13.

  As shown in FIG. 1, the vehicle-side device 21 is provided with a secondary-side rectifier 24 a that rectifies high-frequency power received by the secondary-side resonator 23 into DC power. The DC power rectified by the secondary rectifier 24 a is converted into a predetermined voltage by the secondary DC / DC converter 24 b provided in the vehicle-side device 21, and is supplied to the in-vehicle battery 25 provided in the vehicle-side device 21. Entered.

  Incidentally, a detection sensor 25 a for detecting the charging state of the in-vehicle battery 25 is provided between the secondary side DC / DC converter 24 b and the in-vehicle battery 25. Thereby, the charge condition of the vehicle-mounted battery 25 can be grasped. The secondary side rectifier 24a, the secondary side DC / DC converter 24b, the detection sensor 25a, and the in-vehicle battery 25 constitute the secondary side load 22.

  The non-contact power transmission apparatus 10 includes a plurality of impedance converters 31 and 32 that perform impedance conversion (impedance adjustment). The first impedance converter 31 is provided in the ground side device 11, and the second impedance converter 32 is provided in the vehicle side device 21. Each impedance converter 31 and 32 corresponds to an impedance converter.

  The high-frequency power output from the primary-side high-frequency power source 12 passes through the first impedance converter 31, the primary-side resonator 13, the secondary-side resonator 23, and the second impedance converter 32, and the secondary-side load 22. Is input. That is, the first power transmission path EL1 includes the primary high-frequency power source 12 → the first impedance converter 31 → the primary resonator 13 → the secondary resonator 23 → the second impedance converter 32 → the secondary load 22. It can be said that this is a route for transmitting the.

  Incidentally, if attention is paid to the fact that the first power transmission path EL1 is a path related to the charging of the in-vehicle battery 25, it can be said that the first power transmission path EL1 is the charging path EL1. In the case of performing power transmission using the charging path EL1, the primary side resonator 13 functions as a power transmitter, and the secondary side resonator 23 functions as a power receiver.

Next, a configuration related to the second power transmission path EL2 will be described.
The vehicle-side device 21 is provided with a converter 26 that converts DC power charged in the vehicle-mounted battery 25 into high-frequency power that can be transmitted by the resonators 13 and 23. The converter 26 is provided between the in-vehicle battery 25 (specifically, the detection sensor 25a) and the second impedance converter 32, and in parallel with the secondary side rectifier 24a and the secondary side DC / DC converter 24b. Is provided.

  The converter 26 converts the DC power voltage charged in the in-vehicle battery 25 into a magnitude suitable for power transmission, and the DC power output from the DC / DC converter 26a. A DC / RF converter 26b that converts the power into a high-frequency power having a frequency suitable for power transmission, specifically, the same frequency as the resonant frequency of each of the resonators 13 and 23, is provided.

  According to this configuration, the DC power of the in-vehicle battery 25 is converted into high-frequency power (secondary AC power) by the converter 26 and input to the secondary resonator 23 via the second impedance converter 32. The Then, the secondary-side resonator 23 and the primary-side resonator 13 perform magnetic field resonance, so that the primary-side resonator 13 receives high-frequency power from the secondary-side resonator 23.

  In addition, the ground side device 11 is provided with a primary side load 14 to which high frequency power received by the primary side resonator 13 is input via the first impedance converter 31. The primary side load 14 is provided between the primary side resonator 13 and the external load X, and is provided in parallel with the primary side high frequency power supply 12.

  The primary side load 14 includes a primary side rectifier 14a that rectifies the high-frequency power into DC power, and a primary side DC / DC converter 14b that converts the voltage of the DC power into a voltage having a predetermined magnitude. ing. The DC power converted by the primary side DC / DC converter 14b is input to the external load X. Thereby, it is possible to use the direct-current power of the vehicle-mounted battery 25 for purposes other than those related to the vehicle.

  As described above, the DC power of the in-vehicle battery 25 is supplied to the primary side via the converter 26, the second impedance converter 32, the secondary side resonator 23, the primary side resonator 13, and the first impedance converter 31. It is transmitted to the load 14 and transmitted to the external load X. That is, the second power transmission path EL2 is a secondary side high frequency power source 27 (secondary side AC power source) composed of the in-vehicle battery 25 and the converter 26 → second impedance converter 32 → secondary side resonator 23 → primary side. It can be said that this is a path for transmitting the resonator 13 → the first impedance converter 31 → the primary load 14 (→ the external load X).

  Incidentally, if attention is paid to the fact that the second power transmission path EL2 is a path related to the discharge of the in-vehicle battery 25, it can be said that the second power transmission path EL2 is the discharge path EL2. Further, in the case of performing power transmission using the discharge path EL2, the secondary side resonator 23 functions as a power transmitter, and the primary side resonator 13 functions as a power receiver.

  The non-contact power transmission apparatus 10 includes a primary side relay 15 and a secondary side relay 28 as a pair of switching units that switch the power transmission paths EL1 and EL2. The primary-side relay 15 is provided in the ground-side device 11 and switches the connection destination of the first impedance converter 31 to either the primary-side high-frequency power source 12 or the primary-side load 14. The secondary relay 28 is provided in the vehicle-side device 21 and switches the connection destination of the second impedance converter 32 to either the secondary load 22 or the secondary high-frequency power source 27.

  According to this configuration, the first impedance converter 31 is connected to the primary high-frequency power source 12 by the primary side relay 15, and the second impedance converter 32 is connected to the secondary side load 22 by the secondary side relay 28. The charging path EL1 is formed.

  On the other hand, when the first impedance converter 31 is connected to the primary load 14 by the primary relay 15 and the second impedance converter 32 is connected to the secondary high-frequency power source 27 by the secondary relay 28, A discharge path EL2 is formed.

  The ground side device 11 is provided with a power source side controller 16 for controlling the primary side high frequency power source 12, the first impedance converter 31 and the primary side relay 15. The vehicle-side device 21 is provided with a vehicle-side controller 29 that controls the secondary-side relay 28, the second impedance converter 32, and the secondary-side high-frequency power source 27. Each controller 16 and 29 is configured to be capable of wireless communication. The controllers 16 and 29 can switch the power transmission paths EL1 and EL2 by controlling the relays 15 and 28 while exchanging information with each other.

  Here, among the power transmission paths EL1 and EL2, the relays 15 and 28 including the resonators 13 and 23 form a common path EL3. And each impedance converter 31 and 32 is provided on the common path | route EL3.

Each of these impedance converters 31 and 32 will be described with reference to FIG.
As shown in FIG. 2, the first impedance converter 31 is located between the primary side relay 15 and the primary side resonator 13. The second impedance converter 32 is located between the secondary side resonator 23 and the secondary side relay 28. That is, the first impedance converter 31 and the second impedance converter 32 are provided on both sides of the coupler C including the primary side resonator 13 and the secondary side resonator 23.

  The first impedance converter 31 is composed of an inverted L-type LC circuit including a first inductor 31a and a first capacitor 31b. On the other hand, the second impedance converter 32 is formed of an L-type LC circuit including a second inductor 32a and a second capacitor 32b.

  The constant (impedance) of each impedance converter 31, 32 is variable. Specifically, the capacitances of the capacitors 31b and 32b are variable. The power supply side controller 16 variably controls the constant of the first impedance converter 31 by variably controlling the capacitance of the first capacitor 31b. Similarly, the vehicle-side controller 29 variably controls the constant of the second impedance converter 32 by variably controlling the capacitance of the second capacitor 32b. Each controller 16 and 29 corresponds to a changing unit. The constants of the impedance converters 31 and 32 can be said to be the conversion ratio, inductance, and capacitance.

Here, the present inventors are factors (knowledge) that contribute to transmission efficiency during charging and discharging.
I found. These findings will be described below. For convenience of explanation, the charging time (when power transmission is performed using the charging path EL1) will be described first, and then the discharging time (when power transmission is performed using the discharging path EL2) will be described.

  As shown in FIG. 2, at the time of charging, the primary side high frequency power supply 12 → the first impedance converter 31 → the primary side resonator 13 → the secondary side resonator 23 → the second impedance converter 32 → the secondary side. Power transmission is performed through the charging path EL1 of the load 22.

  In such a situation, the present inventors have found that the real part of the impedance from the output end of the secondary side resonator 23 (secondary side coil 23a) to the secondary side load 22 is the primary side resonator 13 and the secondary side resonance. It has been found that it contributes to the transmission efficiency between the devices 23. Specifically, in the real part of the impedance from the output end of the secondary side resonator 23 to the secondary side load 22, there is a specific resistance value Rout that has a relatively high transmission efficiency compared to other resistance values. Found it to exist. In other words, the real part of the impedance from the output terminal of the secondary resonator 23 to the secondary load 22 has a specific resistance value Rout () in which transmission efficiency is higher than a predetermined resistance value (first resistance value). The second resistance value) was found to exist.

  The specific resistance value Rout is the configuration of the primary side resonator 13 and the secondary side resonator 23 (inductance of each coil 13a, 23a, capacitance of each capacitor 13b, 23b, etc.), primary side resonator 13 and secondary side. This is determined by the distance between the resonators 23.

  Specifically, as shown in FIG. 2, if a virtual load X1 is provided at the input end of the primary side resonator 13, the resistance value of the virtual load X1 is Ra1 and the secondary side resonator 23 (details) Where Rb1 is the resistance value from the output end of the secondary resonator 23) to the virtual load X1, the specific resistance value Rout is √ (Ra1 × Rb1).

  Based on the above knowledge, the second impedance converter 32 has an impedance from the output end of the secondary resonator 23 to the secondary load 22 (impedance at the input end of the second impedance converter 32) having a specific resistance value Rout. The input impedance ZL1 of the secondary side load 22 is impedance-transformed so as to approach (preferably match). That is, the constant of the second impedance converter 32 is set to a value that converts the input impedance ZL1 of the secondary load 22 into the specific resistance value Rout. In addition, the constant of the 2nd impedance converter 32 at the time of charge is set to the receiving side constant ZB.

  Here, the power value of the high-frequency power output from the primary-side high-frequency power source 12 is the impedance from the output end of the primary-side high-frequency power source 12 to the secondary load 22, that is, the input end of the first impedance converter 31. Depends on impedance.

  Therefore, the first impedance converter 31 specifies the impedance from the output end of the secondary side resonator 23 to the secondary side load 22 so that high frequency power of a desired power value is output from the primary side high frequency power supply 12. Impedance conversion is performed on the impedance Zin from the input end of the primary-side resonator 13 to the secondary-side load 22 in a state approaching the resistance value Rout.

  For example, the power value of the output power of the primary side high-frequency power source 12 required for the power value of DC power input to the in-vehicle battery 25 included in the secondary side load 22 to be a power value suitable for charging, Use high-frequency power with a power level suitable for charging. The impedance from the output end of the primary side high frequency power supply 12 to the secondary side load 22 for outputting high frequency power having a power value suitable for charging from the primary side high frequency power supply 12 is defined as the input impedance suitable for charging. Let Zt. In this case, the first impedance converter 31 is configured so that the impedance from the output terminal of the primary side high frequency power source 12 to the secondary side load 22 becomes the input impedance Zt suitable for the charging. Impedance conversion is performed on the impedance Zin from the input end to the secondary load 22. That is, the constant of the first impedance converter 31 is set to a value that converts the impedance Zin from the input end of the primary resonator 13 to the secondary load 22 into an input impedance Zt suitable for charging. In addition, let the constant of the 1st impedance converter 31 at the time of charge be power transmission side constant ZA.

Next, each impedance converter 31 and 32 at the time of discharge is demonstrated.
As shown in FIG. 3, during discharging, the direction of power transmission is reversed and the power transmission path is different. Specifically, at the time of discharging, the secondary high-frequency power source 27 → second impedance converter 32 → secondary resonator 23 → primary resonator 13 → first impedance converter 31 → primary load 14 Power transmission is performed in the discharge path EL2. In this case, as already described, the functions of the resonators 13 and 23 are opposite to those during charging. That is, the secondary side resonator 23 functions as a power transmitter, and the primary side resonator 13 functions as a power receiver. For this reason, the secondary side resonator 23 side becomes an input side, and the primary side resonator 13 side becomes an output side. Therefore, the constants of the impedance converters 31 and 32 are changed so that the constants of the impedance converters 31 and 32 are interchanged.

  Here, the primary side resonator 13 and the secondary side resonator 23 have the same shape. Specifically, at least the capacitance and the inductance of each resonator 13 and 23 are set to be the same. That is, the capacitance of the primary side resonator 13 and the capacitance of the secondary side resonator 23 are set to be the same, and the inductance of the primary side resonator 13 and the inductance of the secondary side resonator 23 are set to be the same. Has been. Further, the input impedance ZL2 of the primary load 14 (impedance of the primary load 14 and the external load X) and the input impedance ZL1 of the secondary load 22 are the same.

  In the above configuration, the constants of the impedance converters 31 and 32 at the time of discharging are set to those obtained by replacing the constants of the impedance converters 31 and 32 at the time of charging. Specifically, the constant of the first impedance converter 31 is set to the power reception side constant ZB, and the constant of the second impedance converter 32 is set to the power transmission side constant ZA.

Next, control by the controllers 16 and 29 will be described.
As shown in FIG. 1, when the vehicle-side controller 29 is arranged at a position where the vehicle can be charged / discharged, in detail, the primary-side resonator 13 and the secondary-side resonator 23 are located at a position where magnetic resonance can occur. When the vehicle is arranged, a charge / discharge enable signal is transmitted to the power supply side controller 16.

The power supply side controller 16 performs a charging / discharging start process, when a charge / discharge possible signal is received. The charge / discharge start process will be described with reference to the flowchart of FIG.
First, in step S101, it is determined whether or not to start power transmission. Specifically, it is determined whether or not a command for instructing the start of power transmission is input from the user. In addition, as an input of the said command, an input terminal may be provided in the ground side apparatus 11, for example, and you may determine based on the input by the input terminal. In addition, it is good also as a structure which is not restricted to the input from a user and determines automatically automatically suitably. Moreover, you may use the navigation apparatus etc. which were provided in the vehicle as an input terminal. In this case, the input information may be transmitted to the power supply side controller 16 and determined based on the information.

  If there is no command to start power transmission, the process is terminated as it is. On the other hand, if a command to start power transmission is input, the process proceeds to step S102, where the current power transmission is charged / Determine which of the discharges. This determination may be made based on input from the user as described above, or may be made automatically based on time or the like.

  If the current power transmission is charging, the process proceeds to step S103, and the charging path EL1 is set. Specifically, the primary side relay 15 is controlled so that the connection destination of the first impedance converter 31 is the primary side high frequency power supply 12, and the charging path setting information is transmitted to the vehicle side controller 29. The vehicle controller 29 controls the secondary relay 28 based on the reception of the charging path setting information, and connects the second impedance converter 32 and the secondary load 22.

  Then, it progresses to step S104 and the constant of each impedance converter 31 and 32 is set for charge. Specifically, the constant of the first impedance converter 31 is set to the power transmission side constant ZA, and the constant of the second impedance converter 32 is set to the power reception side constant ZB.

  When the setting of the constants of the impedance converters 31 and 32 is completed, the process proceeds to step S105, the primary high frequency power supply 12 is controlled so that the high frequency power is output from the primary high frequency power supply 12, and this processing is performed. finish. Thereby, charge of the vehicle-mounted battery 25 is started.

  On the other hand, if the current power transmission is discharging, the process proceeds from step S102 to step S106. In step S106, the discharge path EL2 is set. Specifically, the relays 15 and 28 are controlled so that the connection destination of the first impedance converter 31 is the primary load 14 and the connection destination of the second impedance converter 32 is the secondary high-frequency power source 27. .

  In the subsequent step S107, the constants of the impedance converters 31 and 32 are set for discharge. Specifically, the constant of the first impedance converter 31 is set to the power receiving side constant ZB, and the constant of the second impedance converter 32 is set to the power transmission side constant ZA.

  Then, in step S108, the secondary side high frequency power supply 27 (specifically, the DC / DC converter 26a) is controlled so that the high frequency power is output from the secondary side high frequency power supply 27, and this process is terminated. Thereby, the vehicle-mounted battery 25 is discharged.

The operation of the non-contact power transmission apparatus 10 according to this embodiment will be described below.
A charging path EL1 and a discharging path EL2 are formed, and relays 15 and 28 for switching between the two are provided. Thereby, by switching the relays 15 and 28, the charging path EL1 and the discharging path EL2 can be switched.

  In such a configuration, the impedance converters 31 and 32 are provided on the common path EL3 of the charging path EL1 and the discharging path EL2, and the constants of the impedance converters 31 and 32 are changed between charging and discharging. Is done. As a result, the impedance from the resonator functioning as a power receiver to the load approaches the specific resistance value Rout and high-frequency power having a desired power value can be obtained both during charging and discharging. .

  In particular, the resonators 13 and 23 have the same shape. The input impedance ZL1 of the secondary side load 22 and the input impedance ZL2 of the primary side load 14 are set to be the same. For this reason, when switching from charging to discharging, the transmission efficiency and power value similar to those at the time of charging can be obtained simply by switching the constants of the impedance converters 31 and 32.

In the above embodiment, the following effects can be obtained.
(1) The charging path EL1 and the discharging path EL2 are formed, and relays 15 and 28 for switching between these are provided. Thereby, the vehicle-mounted battery 25 can be used for driving other devices provided other than the vehicle, or can be used for charging a battery (power storage device) different from the vehicle-mounted battery 25. . Therefore, the in-vehicle battery 25 can be used as a household power source or an emergency power source, and the degree of freedom of use of the in-vehicle battery 25 can be improved.

  In this configuration, the impedance converters 31 and 32 are provided on the power transmission paths EL1 and EL2. Thereby, since impedance conversion can be performed both at the time of charge and at the time of discharge, high frequency power can be suitably input to each of the loads 14 and 22. Therefore, high transmission efficiency and output of high-frequency power with a desired power value can be realized both during charging and discharging.

  (2) The impedance converters 31 and 32 are provided on the common path EL3 of the charging path EL1 and the discharging path EL2, specifically, between the relays 15 and 28. As a result, the impedance converters 31 and 32 can be used both at the time of charging and at the time of discharging, and the configuration can be simplified.

  (3) In accordance with the switching of the path in which power transmission is performed, specifically, in each of the impedance converters 31 and 32, depending on when charging and discharging, an optimum constant (high transmission efficiency can be obtained). A constant that can be obtained or a constant that can obtain a high-frequency power having a desired power value is changed. On the other hand, according to this embodiment, it was set as the structure which changes the constant of each impedance converter 31 and 32 according to the time of charge and discharge. As a result, it is possible to achieve high transmission efficiency and output of high-frequency power with a desired power value both during charging and discharging.

  (4) The resonators 13 and 23 have the same shape, and the input impedance ZL1 of the secondary load 22 and the input impedance ZL2 of the primary load 14 are set to be the same. In such a configuration, the constants of the impedance converters 31 and 32 are switched between charging and discharging. Thereby, the same transmission efficiency etc. are implement | achieved at the time of charge and discharge.

  In addition, by adopting a configuration in which replacement is performed as described above, the controllers 16 and 29 do not need to calculate an optimum constant at the time of discharging, and further need to derive by referring to a table in which a plurality of data is set. There is no. Thereby, the constant of each impedance converter 31 and 32 can be easily changed into an optimal constant at the time of discharge. Further, in bidirectional power transmission, the constants of the impedance converters 31 and 32 can be changed by relatively simple control, and the situation where the time required for switching between charge and discharge becomes long can be avoided. it can.

In addition, you may change the said embodiment as follows.
In the embodiment, the impedance converters 31 and 32 are provided on the common path EL3. However, the present invention is not limited to this, and the impedance converters 31 and 32 may be provided on the individual paths of the charging path EL1 and the discharging path EL2. . For example, an impedance converter for charging may be provided between the primary side high frequency power supply 12 and the primary side relay 15 or between the secondary side relay 28 and the secondary side load 22. Similarly, an impedance converter for discharge may be provided between the secondary high frequency power supply 27 and the secondary relay 28 or between the primary relay 15 and the primary load 14. However, from the viewpoint of simplification of the configuration, it is preferable to provide the impedance converters 31 and 32 on the common path EL3.

  In the embodiment, the number of the ground side device 11 and the vehicle side device 21 is one. However, the present invention is not limited to this. For example, two of these are provided, and the ground side device and the vehicle side device for charging, The ground side device and the vehicle side device may be made independent. In this case, the charging path EL1 and the discharging path EL2 are independent.

  In the embodiment, the number of the primary side resonator 13 and the number of the secondary side resonators 23 are one each, but the present invention is not limited to this, and the primary side resonator and the secondary side resonator constituting the charging path EL1 The primary side resonator and the secondary side resonator constituting the discharge path EL2 may be provided separately.

  Each impedance converter 31, 32 may be used for impedance matching. More specifically, during charging, the first impedance converter 31 causes the output impedance of the primary-side high-frequency power source 12 to match the impedance from the output end of the primary-side high-frequency power source 12 to the secondary-side load 22. Alternatively, the impedance Zin from the input end of the primary side resonator 13 to the secondary side load 22 may be impedance-converted.

  Similarly, at the time of charging, the second impedance converter 32 includes an impedance from the output end of the secondary side resonator 23 to the secondary side load 22, and a primary high frequency power source from the output end of the secondary side resonator 23. The input impedance ZL1 of the secondary load 22 may be impedance-converted so that the impedance up to 12 matches.

  In the above configuration, a measuring instrument for measuring reflected wave power, transmission efficiency, etc. is provided, and the constants of the impedance converters 31 and 32 at the time of charging or discharging are set based on the measurement result of the measuring instrument ( It is good also as a structure to calculate. In this case, the constants of the impedance converters 31 and 32 set based on the measurement result of the measuring device may be replaced with the switching of the power transmission. That is, by deriving the constants of the impedance converters 31 and 32 in one state based on the measurement result of the measuring instrument, the constants of the impedance converters 31 and 32 in the other state are naturally derived.

  In the embodiment, the impedance converters 31 and 32 are the inverted L type and the L type, respectively, but are not limited thereto, and the specific configuration thereof is arbitrary. For example, a configuration in which a capacitor is separately provided in series with an L type or an inverted L type may be used, or a π type, a T type, or the like may be used.

  In the embodiment, one impedance converter is provided for each of the ground side device 11 and the vehicle side device 21, but the number of impedance converters provided is not limited to one. For example, as shown in FIG. 5, two impedance converters 41 and 42 may be provided between the primary-side high-frequency power source 12 (primary-side relay 15) and the primary-side resonator 13. Two impedance converters 43 and 44 may be provided between the resonator 23 and the secondary load 22 (secondary relay 28). In this case, it is possible to easily perform impedance conversion as compared with a configuration in which one impedance converter is provided.

  Specifically, for example, during charging, the difference between the specific resistance value Rout and the input impedance ZL1 of the secondary load 22 increases depending on the design values of the coils 13a and 23a, the distance between the coils 13a and 23a, and the like. There is a case. Further, the impedance Zin from the input end of the primary resonator 13 to the secondary load 22 in a situation where the impedance from the output end of the secondary resonator 23 to the secondary load 22 approaches the specific resistance value Rout. And the input impedance Zt suitable for charging may increase. In this case, it may be necessary to use a high breakdown voltage coil or capacitor. Such elements may not be realistic or may be very expensive.

  On the other hand, since the constant of one impedance converter can be reduced by providing two impedance converters in each of the ground side device 11 and the vehicle side device 21 as described above, the above inconvenience is caused. It can be avoided. The same applies to the discharge side.

  In the above configuration, the constant of the first impedance converter 41 and the constant of the fourth impedance converter 44 are switched between charging and discharging, and the constant of the second impedance converter 42 and the third impedance conversion are switched. The constant of the device 43 is replaced.

  In the above configuration, two impedance converters are provided for both the ground-side device 11 and the vehicle-side device 21, but the present invention is not limited to this, and either one of the ground-side device 11 or the vehicle-side device 21 is 2 Two impedance converters may be provided.

  Further, any one of the impedance converters 31 and 32 may be omitted, and one impedance converter may be provided for each of the charging path EL1 and the discharging path EL2. In short, it is sufficient that at least one impedance converter is provided in both the charging path EL1 and the discharging path EL2. In this case, the 1 impedance converter may be provided on either the ground side or the vehicle side.

  In the embodiment, each of the resonators 13 and 23 is provided with each capacitor 13b and 23b having a fixed capacitance. Instead of this, a primary-side variable capacitor having a variable capacitance and 2 It is good also as a structure which provides a secondary side variable capacitor. In this case, the controllers 16 and 29 may be configured to perform variable control of the capacitance of each variable capacitor according to the relative positions of the coils 13a and 23a.

The relative position of each coil 13a, 23a includes not only the distance between each coil 13a, 23a but also the axial direction of each coil 13a, 23a, the mode of superposition of each coil 13a, 23a, etc. Yes. For example, in the configuration in which the primary side resonator 13 and the secondary side resonator 23 are arranged in the vertical direction, the primary side coil 13a and the coil 13a, 23a are superimposed on each other. A positional deviation of the secondary coil 23a can be considered. Further, as the variable control according to the relative position, for example, the variable control based on the measurement result of the transmission efficiency that varies according to the relative position can be considered.

  In the embodiment, the constants are switched between charging and discharging. However, the present invention is not limited to this, and the constants of the impedance converters 31 and 32 may be individually adjusted. In short, the constant of at least one of the impedance converters 31 and 32 may be changed between charging and discharging.

  In the embodiment, the impedance converters 31 and 32 realize both the improvement in transmission efficiency and the output of high-frequency power with a desired power value. However, the present invention is not limited to this, and at least one of the both is realized. The constant of each impedance converter 31 and 32 may be set so that it may be realized. For example, at the time of charging, the constant of the second impedance converter 32 is set to the power receiving side constant ZB, and the constant of the first impedance converter 31 is different from the power transmission side constant ZA, for example, the power factor is “0”. May be set to a value. Further, when switching between charging and discharging is performed, one of the impedance converters 31 and 32 may be changed, and the other constant may not be changed.

  In the embodiment, the in-vehicle battery 25 is used as a part of the secondary-side high frequency power supply 27, but is not limited thereto. For example, when a power generation device that generates power using an internal combustion engine of a vehicle is provided, the AC power of the power generation device may be transmitted to the ground side device 11 via the second power transmission path EL2.

In the embodiment, the external load X is connected to the primary load 14, but is not limited thereto, and may be configured to be connected to a predetermined device provided in the ground device 11.
The external load X is arbitrary as long as it has a predetermined impedance. For example, it may be a home battery or a device that converts it into grid power.

  In the embodiment, the capacitances of the capacitors 31b and 32b are variable. However, the present invention is not limited to this, and the inductances of the inductors 31a and 32a may be variable or both may be variable.

In the embodiment, the charging / discharging start process is configured to be executed by the power supply side controller 16.
In addition, the specific processing content of the charging / discharging start processing is not limited to the above embodiment, and the current power transmission selects either charging / discharging and forms the selected path. If a series of operations such as setting the constants of the impedance converters 31 and 32 according to the selection is performed, the specific processing mode is arbitrary.

The voltage waveform of the high frequency power output from the primary side high frequency power source 12 and the secondary side high frequency power source 27 is arbitrary such as a pulse waveform or a sine wave.
In the embodiment, the capacitors 13b and 23b are provided, but these may be omitted. In this case, magnetic field resonance is performed using the parasitic capacitances of the coils 13a and 23a.

  In the embodiment, the resonance frequency of the primary-side resonator 13 and the resonance frequency of the secondary-side resonator 23 are set to be the same. However, the present invention is not limited to this. It may be allowed.

In the embodiment, the resonators 13 and 23 have the same shape. However, the present invention is not limited to this, and may be different within a range that does not hinder power transmission.
In the embodiment, magnetic field resonance is used in order to realize non-contact power transmission. However, the present invention is not limited to this, and electromagnetic induction may be used.

  In embodiment, the non-contact electric power transmission apparatus 10 was applied to the vehicle, However, It is not restricted to this, You may apply to another apparatus. For example, you may apply to charging / discharging the battery of a mobile telephone.

  (Circle) you may provide the primary side coupling coil couple | bonded with the primary side resonator 13 by electromagnetic induction separately. In this case, the primary side coupling coil and the first impedance converter 31 are connected, and the primary side resonator 13 is configured to receive high frequency power from the primary side coupling coil by electromagnetic induction. Similarly, a secondary side coupling coil that is coupled to the secondary side resonator 23 by electromagnetic induction may be provided, and power may be extracted from the secondary side resonator 23 using the secondary side coupling coil.

  The primary high frequency power supply 12 and the secondary high frequency power supply 27 may be any of a power source, a voltage source, and a current source. Further, the voltage source may be one whose internal resistance is negligible (0Ω), or one whose internal resistance is a predetermined value (for example, 50Ω).

Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.
(A) A pair of switches for switching a path on which power transmission is performed between the first power transmission path and the second power transmission path on both sides of the coupling system including the primary side coil and the secondary side coil. Part is provided,
The non-contact power transmission apparatus according to claim 2, wherein the common path is formed between the pair of switching units.

In addition, the coupler C in the embodiment corresponds to “a coupling system including the primary side coil and the secondary side coil”.
(B) The secondary device is provided in a vehicle,
The secondary load includes an in-vehicle battery,
The first power transmission path is a charging path used for charging the vehicle battery,
The non-contact power transmission device according to claim 1, wherein the second power transmission path is a discharge path used for discharging the in-vehicle battery. .

  DESCRIPTION OF SYMBOLS 10 ... Non-contact electric power transmission apparatus, 11 ... Ground side apparatus (primary side apparatus), 12 ... Primary side high frequency power supply, 13 ... Primary side resonator, 13a ... Primary side coil, 14 ... Primary side load, DESCRIPTION OF SYMBOLS 15 ... Primary side relay, 16 ... Power source side controller, 21 ... Vehicle side apparatus (secondary side apparatus), 22 ... Secondary side load, 23 ... Secondary side resonator, 23a ... Secondary side coil, 25 ... In-vehicle Battery: 27... Secondary side high frequency power supply 28... Secondary side relay 29. Power source side controller 31... First impedance converter (primary side impedance conversion unit) 32. Impedance conversion unit), EL1... Charging path (first power transmission path), EL2... Discharging path (second power transmission path), EL3.

Claims (4)

A primary device having a primary coil to which primary AC power is input;
A secondary side device having a secondary side coil capable of receiving the primary side AC power in a non-contact manner from the primary side coil;
In a non-contact power transmission device comprising:
Secondary AC power is input to the secondary coil,
The primary coil can receive the secondary AC power in a non-contact manner from the secondary coil,
The first power transmission formed by the primary AC power source that outputs the primary AC power and the primary coil, and the secondary coil and secondary load provided in the secondary device. On the route,
Second power transmission formed by the secondary AC power source that outputs the secondary AC power and the secondary coil, and the primary coil and primary load provided in the primary device. A non-contact power transmission device comprising an impedance conversion unit for performing impedance conversion on a path.   The contactless power transmission device according to claim 1, wherein the impedance conversion unit is provided on a common path of the first power transmission path and the second power transmission path.   The apparatus further comprises a changing unit that changes a constant of the impedance conversion unit when the state is switched from a state in which the primary AC power is input to a state in which the secondary AC power is input. Item 3. The non-contact power transmission device according to Item 2. The primary coil constitutes a primary resonator,
The secondary coil constitutes a secondary resonator,
The input impedance of the primary side load and the input impedance of the secondary side load are the same,
The primary side resonator and the secondary side resonator have the same shape,
The impedance conversion unit includes a primary side impedance conversion unit provided in the primary side device, and a secondary side impedance conversion unit provided in the secondary side device,
The changing unit sets a constant set in the primary side impedance conversion unit in a state where the primary side AC power is input to the primary side impedance conversion unit and the secondary side impedance conversion unit. The constant set in the secondary impedance converter is set in the state where the primary AC power is input to the primary impedance converter and the secondary impedance converter while being set in the impedance converter. The non-contact power transmission apparatus according to claim 3, wherein the non-contact power transmission apparatus is set in a primary impedance conversion unit.