JP2014121114A - Power reception apparatus, power transmission apparatus and non-contact power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power reception apparatus, a power transmission apparatus and a non-contact power transmission device in which variable control of impedance in a variable impedance converting section can be carried out suitably.SOLUTION: A non-contact power transmission device 10 includes a high frequency power supply 12, a power transmission unit 13 to which high frequency power is inputted from the high frequency power supply 12, and a power reception unit 23 that can receive high frequency power from the power transmission unit 13, in non-contact. The non-contact power transmission device 10 includes a secondary variable impedance converting section 30 of variable constants, and an RFID tag 51 and an RFID reader 52 for transmitting and receiving an identification signal. Constants of the secondary variable impedance converting section 30 are determined based on the strength of an identification signal received by the RFID reader 52.

Description

  The present invention relates to a power receiving device, a power transmission device, and 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 Literature 1 includes a power transmission device having an AC power source and a primary coil to which AC power is input from the AC power source. The non-contact power transmission apparatus includes a power receiving device having a primary side coil and a secondary side coil capable of magnetic field resonance. Then, AC power is transmitted from the power transmitting device to the power receiving device due to magnetic field resonance between the primary side coil and the secondary side coil. The AC power received by the power receiving device is used for charging a battery provided in the power receiving device. Further, there is a case where communication is performed between the power transmission device and the power reception device in order to specify the power transmission target.

JP 2009-106136 A

  Here, in order to improve the transmission efficiency, an impedance conversion unit for converting to a desired impedance may be provided. In this case, if the relative position of the primary side coil and the secondary side coil fluctuates from a predetermined reference position, the impedance converted by the impedance conversion unit may deviate from a desired impedance. Then, inconveniences such as a decrease in transmission efficiency may occur.

  On the other hand, it is conceivable to perform variable control of the impedance of the variable impedance converter by using a variable impedance converter having a variable impedance as the impedance converter. However, when performing variable control of the impedance of the variable impedance conversion unit, there are concerns about inconveniences such as complicated configuration and complicated control. In particular, when AC power having a smaller power value is used than in the case of charging a vehicle battery in order to reduce power loss, the above inconvenience tends to be significant.

In addition, the situation mentioned above is not restricted to the structure which transmits electric power by magnetic field resonance, For example, it is the same also about the structure which transmits electric power by electromagnetic induction.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a power receiving device, a power transmitting device, and a non-contact power transmission device that can suitably perform variable control of the impedance of the variable impedance converter. To do.

  A power receiving device that achieves the above object is a power receiving device capable of receiving the AC power in a non-contact manner from a power transmission device having a primary side coil to which AC power is input, and the AC power in a non-contact manner from the primary side coil. A secondary coil that can receive power, a load, a variable impedance converter that is provided between the secondary coil and the load, and has a variable impedance, and is used for signal transmission and reception, A transmission unit or a reception unit in which a signal intensity of the signal to be changed varies depending on a relative position of the primary side coil and the secondary side coil, and the impedance of the variable impedance conversion unit is received It is determined based on the signal strength of the signal.

  According to such a configuration, by transmitting and receiving signals, for example, a power transmitting device and a power receiving device that perform power transmission can be authenticated. Then, by determining the impedance of the variable impedance converter using the configuration for transmitting and receiving the signal, it is possible to simplify the configuration and simplify the variable control of the constant of the variable impedance converter. it can.

  A power transmission device that achieves the above object includes: a power transmission device that includes a primary side coil to which AC power is input and that can transmit the AC power in a contactless manner to a power reception device having a secondary side coil; A variable impedance converter provided on the input side of the secondary coil and used for variable transmission and reception of signals, and the signal strength of the received signal is the primary coil and the secondary coil A transmission unit or a reception unit that varies according to the relative position of the coil, wherein the impedance of the variable impedance conversion unit is determined based on the signal strength of the received signal.

  According to such a configuration, by transmitting and receiving signals, for example, a power transmitting device and a power receiving device that perform power transmission can be authenticated. Then, by determining the impedance of the variable impedance converter using the configuration for transmitting and receiving the signal, it is possible to simplify the configuration and simplify the variable control of the constant of the variable impedance converter. it can.

  A non-contact power transmission device that achieves the above object includes a power transmission device having a primary coil to which AC power is input, and a secondary coil that can receive the AC power in a non-contact manner from the primary coil. In a non-contact power transmission apparatus comprising a power receiving device, the power transmission device and the power receiving device are provided in at least one of the power transmission device and a variable impedance conversion unit having a variable impedance, and transmit and receive signals. A transmission unit provided in one of the device and the power receiving device, and a reception unit provided in the other, the signal strength of the signal received by the reception unit is the primary coil and the secondary The impedance of the variable impedance converter is variably controlled based on the signal strength of the signal received by the receiver. Characterized in that it comprises a control unit for.

  According to such a configuration, by transmitting and receiving signals, for example, a power transmitting device and a power receiving device that perform power transmission can be authenticated. Then, by determining the impedance of the variable impedance converter using the configuration for transmitting and receiving the signal, it is possible to simplify the configuration and simplify the variable control of the constant of the variable impedance converter. it can.

  According to this invention, variable control of the impedance of the variable impedance converter can be suitably performed.

The circuit diagram which shows the electrical constitution of the non-contact electric power transmission apparatus provided with the power transmission apparatus and the power receiving apparatus. The flowchart which shows the charge start process performed with a power supply side controller. The flowchart which shows the charge start process performed with a vehicle side controller. The conceptual diagram for demonstrating a map.

Hereinafter, an embodiment of a power receiving device, a power transmission device, and a non-contact power transmission device (non-contact power transmission system) will be described.
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 a power transmission device (primary side device), and the vehicle side device 21 corresponds to a power receiving device (secondary side device).

  The ground side device 11 includes a high frequency power source 12 (AC power source) capable of outputting high frequency power (AC power) having a predetermined frequency. The high-frequency power source 12 is configured to be able to output a plurality of types of high-frequency power having different power values using the system power.

  The high-frequency power output from the high-frequency power source 12 is transmitted to the vehicle-side device 21 in a non-contact manner, and input to the vehicle battery (power storage unit) 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 a power transmitter 13 (primary side resonance circuit) provided in the ground side device 11. And a power receiver 23 (secondary resonance circuit) provided in the vehicle-side device 21.

  The power transmitter 13 and the power receiver 23 have the same configuration, and both are configured to be capable of magnetic field resonance. Specifically, the power transmitter 13 includes a resonance circuit including a primary coil 13a and a primary capacitor 13b connected in parallel. The power receiver 23 is composed of a resonance circuit including a secondary coil 23a and a secondary capacitor 23b connected in parallel. Both resonance frequencies are set to be the same.

  According to such a configuration, when high-frequency power is input to the power transmitter 13 (primary coil 13a), the power transmitter 13 and the power receiver 23 (secondary coil 23a) undergo magnetic field resonance. As a result, the power receiver 23 receives a part of the energy of the power transmitter 13. That is, the power receiver 23 receives high frequency power from the power transmitter 13.

  The vehicle-side device 21 rectifies the high-frequency power received by the power receiver 23 into DC power, and has a semiconductor element (diode) that operates by applying a predetermined threshold voltage value. A rectifier (rectifier unit) 24 is provided. The DC power rectified by the rectifier 24 is input to the vehicle battery 22.

  The ground side device 11 is provided with a power source side controller 14 that controls the ground side device 11 such as the high frequency power source 12. The power supply side controller 14 controls on / off of the high frequency power supply 12 and controls the power value of the high frequency power output from the high frequency power supply 12.

The vehicle-side device 21 is provided with a vehicle-side controller 25 configured to be capable of wireless communication with the power supply-side controller 14. Each controller 14 and 25 corresponds to a “control unit”.
In addition, the vehicle-side device 21 is provided with a detection sensor 26 that detects the amount of charge (charge state, SOC) of the vehicle battery 22. The detection sensor 26 transmits a detection result to the vehicle-side controller 25. Thereby, the vehicle-side controller 25 can grasp the charge amount of the vehicle battery 22.

  The vehicle-side device 21 includes a secondary-side variable impedance converter 30 whose constant (impedance) is variable. The secondary-side variable impedance converter 30 is provided on the power transmission path from the power receiver 23 to the vehicle battery 22, and is specifically provided between the power receiver 23 and the rectifier 24. The high-frequency power received by the power receiver 23 is input to the rectifier 24 and subsequent parts via the secondary variable impedance converter 30.

  Similarly, the ground-side device 11 includes a primary-side variable impedance converter 40 whose constant (impedance) is variable. The primary side variable impedance converter 40 is provided on the power transmission path between the high frequency power source 12 and the power transmitter 13, and the high frequency power output from the high frequency power source 12 passes through the primary side variable impedance converter 40. To the power transmitter 13. The constant (impedance) can be said to be a conversion ratio, an inductance, or a capacitance.

  Here, the present inventors have contributed to the transmission efficiency between the power transmitter 13 and the power receiver 23 by the real part of the impedance from the output end of the power receiver 23 (secondary coil 23a) to the vehicle battery 22. I found out. Specifically, it has been found that a specific resistance value Rout having relatively higher transmission efficiency than other resistance values exists in the real part of the impedance from the output terminal of the power receiver 23 to the vehicle battery 22. . In other words, the real part of the impedance from the output terminal of the power receiver 23 to the vehicle battery 22 has a specific resistance value Rout (second resistance value) in which transmission efficiency is higher than a predetermined resistance value (first resistance value). ) Existed.

  Specifically, if a virtual load X1 is provided at the input end of the power transmitter 13, the resistance value of the virtual load X1 is Ra1, and the virtual load X1 is received from the power receiver 23 (specifically, the output end of the power receiver 23). The specific resistance value Rout is √ (Ra1 × Rb1) where the resistance value up to is Rb1.

  Based on the above knowledge, the secondary-side variable impedance converter 30 has an impedance from the output end of the power receiver 23 to the vehicle battery 22 (impedance at the input end of the secondary-side variable impedance converter 30) is a specific resistance value Rout. The impedance is converted so as to approach (preferably match).

  Here, the power value of the high-frequency power output from the high-frequency power source 12 depends on the impedance from the output end of the high-frequency power source 12 to the vehicle battery 22 (impedance at the input end of the primary-side variable impedance converter 40).

  In such a configuration, the primary-side variable impedance converter 40 is configured such that the impedance from the output terminal of the power receiver 23 to the vehicle battery 22 has a specific resistance value Rout so that high-frequency power of a desired power value is output from the high-frequency power source 12. The impedance Zin from the input end of the power transmitter 13 to the vehicle battery 22 in a situation approaching is impedance-converted.

  For example, the power value of the output power of the high-frequency power source 12 required for the power value of the direct-current power input to the vehicle battery 22 to be a power value suitable for charging is the high-frequency power having a power value suitable for charging. To do. The impedance from the output terminal of the high-frequency power source 12 for outputting high-frequency power having a power value suitable for charging from the high-frequency power source 12 to the vehicle battery 22 is defined as an input impedance Zt suitable for charging. In this case, the primary-side variable impedance converter 40 transmits the power transmitter 13 so that the impedance from the output terminal of the high-frequency power source 12 to the vehicle battery 22 approaches (preferably matches) the input impedance Zt suitable for the charging. The impedance Zin from the input terminal to the vehicle battery 22 is impedance-converted.

  In other words, the high frequency power source 12 is configured to be able to output high frequency power of a desired power value under the condition that the impedance from the output end of the high frequency power source 12 to the vehicle battery 22 is the input impedance Zt suitable for the charging. It can be said that it is done.

  The specific resistance value Rout is determined by the configuration of the power transmitter 13 and the power receiver 23 (the shape and inductance of the coils 13a and 23a, the capacitance of the capacitors 13b and 23b, etc.), and the relative position of the power transmitter 13 and the power receiver 23. Is. For this reason, when the power transmitter 13 and the power receiver 23 deviate from a predetermined reference position, that is, when the relative position of the power transmitter 13 and the power receiver 23 varies, the specific resistance value Rout varies.

  On the other hand, the non-contact power transmission device 10 can follow the change in the relative position between the power transmitter 13 and the power receiver 23. This point will be described below together with detailed configurations of the variable impedance converters 30 and 40.

  The secondary side variable impedance conversion unit 30 includes a plurality of (for example, three) impedance converters (secondary side impedance conversion units) 31 to 33. The impedance converters 31 to 33 are provided in parallel with each other. Each impedance converter 31 to 33 is configured by an L-type LC circuit, and the constants of the impedance converters 31 to 33 are different from each other. In this case, it can be said that the secondary-side variable impedance converter 30 can take a plurality of (three) constants.

  The secondary variable impedance converter 30 includes a relay 34 that switches the connection destination of the power receiver 23 and the rectifier 24 (vehicle battery 22) to one of the impedance converters 31 to 33. The relay 34 is provided on both sides of each impedance converter 31 to 33. When the relay 34 is switched, the impedance converter to which the high frequency power received by the power receiver 23 is transmitted is switched.

  Similar to the secondary variable impedance converter 30, the primary variable impedance converter 40 includes a plurality of (for example, three) impedance converters (primary impedance converters) 41 to 43 having different constants. Yes. The primary-side variable impedance converter 40 includes a relay 44 that switches the connection destination of the high-frequency power source 12 and the power transmitter 13 to any one of the plurality of impedance converters 41 to 43. The impedance converters 41 to 43 are constituted by, for example, inverted L-type LC circuits.

  As described above, since each of the variable impedance conversion units 30 and 40 has a variable constant, the constant can be changed according to a change in the relative position between the power transmitter 13 and the power receiver 23.

  Here, the non-contact power transmission apparatus 10 includes a communication system 50 that wirelessly transmits and receives information between the ground-side device 11 and the vehicle-side device 21 separately from the controllers 14 and 25. The communication system 50 includes an RFID tag 51 as a transmission unit provided in the vehicle-side device 21 and an RFID reader 52 as a reception unit provided in the ground-side device 11. Identification information of the vehicle-side device 21 is stored in the RFID tag 51. When the RFID tag 51 and the RFID reader 52 are arranged within a predetermined range, an identification signal including the identification information is received from the RFID tag 51. The identification signal is transmitted and received by the RFID reader 52. The identification information is, for example, ID information for specifying the vehicle-side device 21.

  Incidentally, the predetermined range is set to be the same as or narrower than the range in which power can be transmitted between the power transmitter 13 and the power receiver 23, and the controllers 14 and 25 can exchange information. It is set narrower than possible. In addition, the range in which each controller 14 and 25 can exchange information is set wider than the range in which power transmission can be performed between the power transmitter 13 and the power receiver 23.

  The RFID reader 52 is configured to transmit the received identification signal and the signal strength of the identification signal to the power supply side controller 14. More specifically, the signal strength of the identification signal transmitted from the RFID tag 51 is a predetermined constant value. That is, the power value for transmitting the identification signal is constant. The signal strength of the identification signal received by the RFID reader 52 varies depending on the relative position between the RFID tag 51 and the RFID reader 52. Specifically, the signal strength of the identification signal received by the RFID reader 52 increases as the distance between the RFID tag 51 and the RFID reader 52 decreases. When receiving the identification signal, the RFID reader 52 detects the signal strength of the identification signal together with the identification signal, and transmits both pieces of information to the power supply side controller 14.

  The signal strength is, for example, a power value related to an identification signal received by the RFID reader 52, that is, a power value P of RFID received power (hereinafter simply referred to as RFID received power value P). However, the present invention is not limited to this, and a voltage value, a current value, or the like related to an identification signal received by the RFID reader 52 may be used.

  Incidentally, since the RFID tag 51 and the power receiver 23 are provided in the vehicle-side device 21, and the RFID reader 52 and the power transmitter 13 are provided in the ground-side device 11, the distance between the RFID tag 51 and the RFID reader 52 is The distance L between the power transmitter 13 and the power receiver 23 is correlated.

  The power supply side controller 14 authenticates the vehicle side device 21 to be charged based on the reception of the identification signal from the RFID reader 52. And each controller 14 and 25 performs the charge start process which performs control of electric power transmission and the variable control of the constant of each variable impedance conversion part 30 and 40 through the exchange of information mutually.

  The charging start process executed by the controllers 14 and 25 will be described with reference to FIGS. First, the charging start process executed by the power supply side controller 14 will be described using FIG. 2, and then the charging start process executed by the vehicle side controller 25 will be described using FIG. 3.

  As shown in FIG. 2, first, in step S <b> 101, the RFID received power value P is grasped based on the information transmitted from the RFID reader 52. Thereafter, in step S102, constant determination processing for determining constants of the variable impedance converters 30 and 40 is executed based on the RFID received power value P. In the constant determination process, the constants of the variable impedance conversion units 30 and 40 are determined by referring to the map 14a (see FIG. 1) stored in the storage unit of the power supply side controller 14.

  As shown in FIG. 4, the map 14a includes primary side number information Z1 (x) that is number information of the impedance converters 41 to 43 of the primary side variable impedance converter 40 with respect to the RFID received power value P. And secondary side number information Z2 (x) that is number information of the impedance converters 31 to 33 of the secondary side variable impedance converter 30 are set in association with each other. In the following description, the primary side number information Z1 (x) is also simply referred to as Z1 (x), and the secondary side number information Z2 (x) is also simply referred to as Z2 (x).

  Specifically, P1 <P ≦ P2 (P1 <P2), Z1 (1) unique to the first impedance converter 41 of the primary variable impedance converter 40 and the second variable impedance converter 30 of the primary side. Z2 (1) unique to the one impedance converter 31 is set.

  In P2 <P ≦ P3 (P2 <P3), Z1 (2) unique to the second impedance converter 42 of the primary variable impedance converter 40 and the second impedance converter of the secondary variable impedance converter 30 32 unique Z2 (2) is set.

  In P3 <P ≦ P4 (P3 <P4), Z1 (3) unique to the third impedance converter 43 of the primary variable impedance converter 40 and the third impedance converter of the secondary variable impedance converter 30 33 unique Z2 (3) is set.

  Here, the relationship between the constants of the impedance converters 41 to 43 of the primary variable impedance converter 40 and the impedance converters 31 to 33 of the secondary variable impedance converter 30 and the RFID received power value P will be described. The RFID received power value P varies depending on the relative position between the power transmitter 13 and the power receiver 23, specifically, the distance L between the power transmitter 13 and the power receiver 23. For this reason, the distances L1 to L4 between the power transmitter 13 and the power receiver 23 are associated with the power values P1 to P4. The distance L between the power transmitter 13 and the power receiver 23 can also be said to be the distance between the coils 13a and 23a.

  In such a configuration, the constant of the first impedance converter 31 of the secondary variable impedance converter 30 is the vehicle-use variable from the output end of the power receiver 23 under the condition of P1 <P ≦ P2 (L1 <L ≦ L2). The impedance up to the battery 22 is set so as to approach the specific resistance value Rout. And the constant of the 1st impedance converter 41 of the primary side variable impedance conversion part 40 is set so that the input impedance Zt suitable for charge may be approximated on the conditions which are P1 <P <= P2.

  Similarly, the constant of the second impedance converter 32 of the secondary variable impedance converter 30 is the vehicle battery from the output terminal of the power receiver 23 under the condition of P2 <P ≦ P3 (L2 <L ≦ L3). The impedance up to 22 is set to approach the specific resistance value Rout. And the constant of the 2nd impedance converter 42 of the primary side variable impedance conversion part 40 is set so that it may approach the input impedance Zt suitable for charge on the conditions which are P2 <P <= P3.

  Further, the constant of the third impedance converter 33 of the secondary side variable impedance converter 30 is the vehicle battery 22 from the output terminal of the power receiver 23 under the condition of P3 <P ≦ P4 (L3 <L ≦ L4). Is set to approach the specific resistance value Rout. And the constant of the 3rd impedance converter 43 of the primary side variable impedance conversion part 40 is set so that it may approach the input impedance Zt suitable for charge on the conditions which are P3 <P <= P4.

  Returning to the description of step S102 in FIG. 2, in the constant determination process, Z1 (x) and Z2 (x) corresponding to the RFID received power value P grasped in step S101 are grasped by referring to the map 14a. . In step S103, among the impedance converters 41 to 43 of the primary side variable impedance converter 40, the one corresponding to Z1 (x) grasped in step S102 is connected to the high frequency power supply 12 and the power transmitter 13. As described above, the relay 44 is controlled. Furthermore, in step S104, the constant information of the secondary variable impedance converter 30, that is, Z2 (x) grasped in step S102 is transmitted.

  Thereafter, in step S105, the process waits until a power output instruction is received. If a power output instruction is received, output of high-frequency power is started in step S106, and this process ends.

  Next, a charging start process executed by the vehicle-side controller 25 will be described with reference to FIG. First, in step S201, the process waits until constant information is received. The constant information is transmitted in the process of step S <b> 104 executed by the power supply side controller 14.

  When the constant information is received, the process proceeds to step S202, and variable control of the constant of the secondary side variable impedance converter 30 is performed. Specifically, among the impedance converters 31 to 33 of the secondary variable impedance converter 30, the one corresponding to Z2 (x) received as constant information is connected to the power receiver 23 and the rectifier 24. The relay 34 is controlled. Thereafter, in step S203, a power output instruction is transmitted and the present process is terminated. Thereby, after the variable control of the constants of the variable impedance converters 30 and 40 is performed, the output of the high frequency power from the high frequency power source 12 is started.

Next, the operation of this embodiment will be described.
In a configuration for authenticating (specifying) the vehicle-side device 21 to be charged (power transmission target) by communication between the RFID tag 51 and the RFID reader 52, the variation varies depending on the distance L between the power transmitter 13 and the power receiver 23. Based on the RFID received power value P, the constants of the variable impedance converters 30 and 40 are determined. Specifically, by referring to the map 14a in which the RFID received power value P is associated with Z1 (x) and Z2 (x), which are information on the constants of the variable impedance converters 30 and 40, RFID reception is performed. Z1 (x) and Z2 (x) corresponding to the power value P are grasped.

According to the embodiment described in detail above, the following excellent effects are obtained.
(1) The signal strength of the identification signal received by the RFID reader 52 provided in the ground side device 11 in the vehicle side device 21 provided with the RFID tag 51 used for transmission / reception of the identification signal related to the vehicle side device 21. A constant of the secondary variable impedance converter 30 is determined based on the RFID received power value P. Thereby, the constant of the secondary side variable impedance conversion part 30 can be determined easily using the structure for authenticating charging object.

  Moreover, in the ground side apparatus 11 provided with the RFID reader | leader 52 used for transmission / reception of the identification signal regarding the vehicle side apparatus 21, it was set as the structure which determines the constant of the primary side variable impedance conversion part 40 based on RFID received power value P. . Thereby, the constant of the primary side variable impedance conversion part 40 can be determined easily using the structure for authenticating charging object.

  The above-described effects will be described in detail. Usually, the variable control of the constants of the variable impedance converters 30 and 40 has a power value that is higher than that during charging from the high-frequency power source 12 at the stage before starting the power transmission to the vehicle battery 22. This is performed based on the measurement result of a measuring instrument that measures a voltage waveform and a current waveform such that a small adjustment power is output. In this case, there is a concern that the electrical configuration is complicated and the control is complicated due to the necessity of providing a measuring instrument.

  On the other hand, in this embodiment, the signal strength (RFID received power value P) of the identification signal received by the RFID reader 52 used for authentication of the vehicle-side device 21 that is the target of power transmission is the power transmitter 13 and Focusing on the fact that it varies depending on the distance L between the power receivers 23, the constants of the variable impedance converters 30 and 40 are determined based on the RFID received power value P. As a result, the constants of the variable impedance converters 30 and 40 can be determined without performing complicated control as described above.

  (2) For the RFID received power value P, a map 14a that is data in which information (Z1 (x) and Z2 (x)) regarding the constants of the variable impedance converters 30 and 40 is set is provided, and the map 14a The constants of the variable impedance converters 30 and 40 are determined by referring to FIG. Thereby, the variable impedance conversion units 30 and 40 can be determined without performing complicated processing such as calculating the constants of the variable impedance conversion units 30 and 40.

  (3) Each of the variable impedance converters 30 and 40 includes a plurality of impedance converters 31 to 33 and 41 to 43. Then, any one of the impedance converters 31 to 33 and 41 to 43 is selected and switched in correspondence with the RFID received power value P. Thereby, the variable control of the constants of the variable impedance converters 30 and 40 can be performed more simply, and a desired constant can be realized without using an element having an excessively wide variable range.

In addition, you may change the said embodiment as follows.
In the embodiment, the RFID tag 51 is provided in the vehicle-side device 21 and the RFID reader 52 is provided in the ground-side device 11. However, the present invention is not limited to this. For example, an RFID reader 52 may be provided in the vehicle side device 21, an RFID tag 51 may be provided in the ground side device 11, and an identification signal related to the ground side device 11 may be transmitted and received. In this case, the vehicle-side controller 25 may be configured to transmit information related to the RFID received power value P received from the RFID reader 52 to the power supply-side controller 14.

  ○ The type of the RFID tag 51 is arbitrary, such as passive, active, and semi-active. Further, the transmission method between the RFID tag 51 and the RFID reader 52 is also arbitrary such as electromagnetic induction and radio waves.

  In the embodiment, the RFID tag 51 and the RFID reader 52 are used as the transmission unit and the reception unit that transmit and receive the identification signal. However, the present invention is not limited to this. In short, the identification signal is transmitted and received, and the specific configuration is arbitrary as long as the signal intensity varies according to the distance L between the power transmitter 13 and the power receiver 23. For example, the configuration may be such that authentication is performed using light such as infrared communication. In this case, for example, one of the ground side device 11 and the vehicle side device 21 may be provided with a light emitting unit, and the other may be provided with a light receiving unit. Moreover, it is good also as a structure which arrange | positions several light-receiving parts in an array form, and estimates the relative position of the power transmitter 13 and the power receiver 23 from the light-receiving part which reacted. Furthermore, a plurality of light emitting units arranged in an array and a plurality of light receiving units arranged in the same array may be provided, and the relative position may be specified based on the coordinates of the reacted light emitting units. In the above configuration, the signal intensity of the identification signal is the light intensity.

  ○ The content of the identification information is arbitrary. For example, a configuration in which information for specifying the ground side device 11 or the vehicle side device 21 is set, or a configuration in which null data is set may be used. In short, as long as the distance L between the power transmitter 13 and the power receiver 23 can be derived based on the signal strength, the content of the signal transmitted and received between the RFID tag 51 and the RFID reader 52 is arbitrary.

  In the embodiment, the signal strength of the identification information transmitted from the RFID tag 51 is a predetermined constant value, but is not limited thereto, and may be a variable value. In this case, the distance L between the power transmitter 13 and the power receiver 23 may be derived based on the signal strength of the identification information transmitted from the RFID tag 51 and the signal strength of the identification information received by the RFID reader 52. As an example of the above configuration, for example, the RFID tag 51 transmits an identification signal and the signal strength of the identification signal transmitted from the RFID tag 51, and the RFID reader 52 receives both pieces of information. Then, the attenuation rate is calculated from the signal strength of the identification information transmitted from the RFID tag 51 and the signal strength of the identification information received by the RFID reader 52, and the power transmitter 13 and the power receiver 23 are based on the attenuation rate. A distance L between them is derived.

  In the embodiment, the power supply controller 14 is provided with the map 14a, and the power supply controller 14 executes the constant determination process. However, the present invention is not limited to this, and the control subject of the constant determination process is arbitrary. . For example, the map 14 a may be provided in the vehicle-side controller 25 and the vehicle-side controller 25 may execute a constant determination process, or a dedicated controller may be provided separately from the controllers 14 and 25.

  In the embodiment, the variable impedance conversion units 30 and 40 are provided in both the ground side device 11 and the vehicle side device 21, but either one may be omitted. Further, the constant of any one of the impedance converters may be fixed.

  In the embodiment, the variable impedance conversion units 30 and 40 are provided one by one in the ground side device 11 and the vehicle side device 21, but the present invention is not limited to this, and for example, a configuration in which two or more are provided. Good.

  In the embodiment, each of the variable impedance converters 30 and 40 has a configuration including a plurality of impedance converters having different constants. However, the present invention is not limited to this, for example, a variable capacitor having a variable capacitance and a variable inductance. A configuration including one LC circuit having at least one of the variable inductors may be employed.

  Moreover, it is good also as a structure by which the constant of each impedance converter 31-33, 41-43 is variable. In this case, it is good also as a structure which carries out the variable control of the constant of each impedance converter 31-33, 41-43 corresponding to the fluctuation | variation etc. of the impedance of the battery 22 for vehicles.

  In the embodiment, the impedance converters 41 to 43 are configured by inverted L-type LC circuits, and the impedance converters 31 to 33 are configured by L-type LC circuits, but the specific circuit configuration is arbitrary. It is. For example, a π type, a T type, or the like may be used.

  In embodiment, although the impedance converters 31-33 and the impedance converters 41-43 were comprised by LC circuit, the specific structure is arbitrary. For example, a transformer may be used.

  The primary variable impedance converter 40 converts the impedance Zin from the input end of the power transmitter 13 to the vehicle battery 22 so that the power factor is improved (reactance approaches 0). Also good.

  ○ Instead of (or in addition to) the secondary variable impedance converter 30, a DC / DC converter having a switching element that periodically switches (on / off) may be provided between the rectifier 24 and the vehicle battery 22. Good. In this case, the impedance of the input end of the DC / DC converter is adjusted by adjusting the on / off duty ratio of the switching element, and thereby the impedance from the output end of the power receiver 23 to the vehicle battery 22 is changed to a specific resistance value. It is good also as a structure close | similar to Rout. In this case, the DC / DC converter corresponds to the “variable impedance converter”, and the vehicle battery 22 corresponds to the “load”. That is, the “load” is input with high-frequency power received by the power receiver 23 (secondary coil 23a) or DC power rectified therefrom.

  A power source may be adopted as the high frequency power source 12 and the variable impedance conversion units 30 and 40 may be used for impedance matching. Specifically, the primary-side variable impedance conversion unit 40 is connected from the input end of the power transmitter 13 to the vehicle so that the impedance from the output end of the high-frequency power source 12 to the vehicle battery 22 matches the output impedance of the high-frequency power source 12. The impedance Zin up to the battery 22 may be impedance-converted.

  Further, the secondary side variable impedance converter 30 receives the input of the rectifier 24 so that the impedance from the output terminal of the power receiver 23 to the vehicle battery 22 matches the impedance from the output terminal of the power receiver 23 to the high frequency power supply 12. The impedance from the end to the vehicle battery 22 may be converted.

  In such a configuration, the controllers 14 and 25 may perform variable control of the constants of the variable impedance converters 30 and 40 so that the reflected wave power becomes small. In this case, variable control of the constants of the variable impedance converters 30 and 40 may be performed simultaneously.

In the embodiment, the resonance frequency of the power transmitter 13 and the resonance frequency of the power receiver 23 are set to be the same. However, the present invention is not limited to this, and may be different within a range in which power transmission is possible.
In embodiment, although the power transmission device 13 and the power receiving device 23 were the same structures, it is not restricted to this, A different structure may be sufficient.

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, 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, it may be applied to charge a battery of a mobile phone.

In the embodiment, the high-frequency power received by the power receiver 23 is used for charging the vehicle battery 22, but is not limited thereto, and may be used for driving another device, for example.
The high frequency power supply 12 may be any of a power source, a voltage source, and a current source.

In the embodiment, the high-frequency power source 12 is provided, but the present invention is not limited to this, and the system power source and the primary-side variable impedance converter 40 may be directly connected by omitting this.
The power transmitter 13 may have a configuration including a resonance circuit including a primary side coil 13a and a primary side capacitor 13b, and a primary side coupling coil that is coupled to the resonance circuit by electromagnetic induction. Similarly, the power receiver 23 may include a resonance circuit including a secondary coil 23a and a secondary capacitor 23b, and a secondary coupling coil coupled to the resonance circuit by electromagnetic induction.

Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.
(A) The power receiving device according to claim 1, wherein the transmitting unit is an RFID tag, and the receiving unit is an RFID reader.

  (B) The impedance of the variable impedance converter is determined using data in which the signal intensity of the signal and information on the impedance of the variable impedance converter are associated with each other. The power receiving device described in 1.

  (C) The non-contact power transmission device according to claim 3, wherein the transmission unit and the reception unit authenticate the power transmission device and the power reception device that perform power transmission by performing communication of the signal.

  DESCRIPTION OF SYMBOLS 10 ... Non-contact electric power transmission apparatus, 11 ... Ground side apparatus (power transmission apparatus), 12 ... High frequency power supply, 13a ... Primary side coil, 14a ... Map, 21 ... Vehicle side apparatus (power receiving apparatus), 22 ... Vehicle battery, 23a ... secondary coil, 30 ... secondary variable impedance converter, 40 ... primary variable impedance converter, 51 ... RFID tag (transmitter), 52 ... RFID reader (receiver).

Claims (3)

In a power receiving device capable of receiving the AC power in a contactless manner from a power transmitting device having a primary side coil to which AC power is input,
A secondary coil capable of receiving the AC power in a non-contact manner from the primary coil;
Load,
A variable impedance converter provided between the secondary coil and the load and having a variable impedance;
A transmitter or receiver that is used for signal transmission and reception, and in which the signal strength of the received signal varies depending on the relative position of the primary coil and the secondary coil;
With
The impedance of the variable impedance converter is determined based on the signal intensity of the received signal. In a power transmission device having a primary coil to which AC power is input and capable of transmitting the AC power in a contactless manner to a power receiving device having a secondary coil,
A variable impedance converter provided on the input side of the primary coil and having a variable impedance;
A transmitter or receiver that is used for signal transmission and reception, and in which the signal strength of the received signal varies depending on the relative position of the primary coil and the secondary coil;
With
The impedance of the variable impedance converter is determined based on the signal strength of the received signal. A power transmission device having a primary coil to which AC power is input;
A power receiving device having a secondary side coil capable of receiving the AC power in a non-contact manner from the primary side coil;
In a non-contact power transmission device comprising:
A variable impedance converter provided in at least one of the power transmitting device and the power receiving device, and having a variable impedance;
Transmitting and receiving signals, a transmission unit provided in one of the power transmission device and the power reception device and a reception unit provided in the other,
With
The signal strength of the signal received by the receiving unit varies depending on the relative position of the primary side coil and the secondary side coil,
A non-contact power transmission apparatus comprising: a control unit that variably controls the impedance of the variable impedance conversion unit based on the signal strength of the signal received by the reception unit.