JP2014075885A - Power transmission apparatus, power reception apparatus and non-contact power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission apparatus and a power reception apparatus which can adequately address the difference of specification, in a configuration provided with an impedance conversion section, and to provide a non-contact power transmission device including these apparatus.SOLUTION: A non-contact power transmission device 10 consists of a ground side apparatus 11 and a vehicle side apparatus 21. The ground side apparatus 11 is provided with a high frequency power supply 12 which can change the output frequency, and a power transmission unit 13 which can change the resonance frequency. The vehicle side apparatus 21 is provided with a power reception unit 23 which can receive high frequency power in non-contact, and a load 22 to which the high frequency power received by the power reception unit 23 is inputted. The ground side apparatus 11 is provided with a first impedance converter 31, and when the output frequency and the resonance frequency of the power transmission unit 13 are changed, variable control of the constants of the first impedance converter 31 is performed.

Description

  The present invention relates to a power transmission device, a power reception device, and a non-contact 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 side resonance unit (primary side 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 resonance unit and a secondary side resonance unit (secondary side coil) capable of magnetic field resonance. Then, AC power is transmitted from the power transmission device to the power reception device by magnetic resonance between the primary side resonance unit and the secondary side resonance unit.

JP 2009-106136 A

  In the above power transmitting device and power receiving device, an impedance converter may be provided to obtain a desired impedance. Further, due to the difference in specifications between the power transmitting device and the power receiving device, for example, when the resonance frequency of each resonance unit is different, power transmission may be difficult or transmission efficiency may be reduced.

  An object of the present invention is made in view of the above-described circumstances, and in a configuration in which an impedance conversion unit is provided, a power transmission device, a power reception device, and these devices that can appropriately cope with a difference in specifications. An object of the present invention is to provide a non-contact power transmission device provided.

  In order to achieve the above object, an invention according to claim 1 includes an AC power source capable of outputting AC power, and a primary side resonance unit to which the AC power is input, and has a secondary side resonance unit. In a power transmission device capable of transmitting the AC power in a non-contact manner with respect to a power receiving device, a primary side impedance conversion unit provided between the AC power source and the primary side resonance unit and having a variable impedance is provided. The frequency of the AC power output from the AC power source and the resonance frequency of the primary side resonance unit can be changed, and the impedance of the primary side impedance conversion unit is the AC output from the AC power source. When the frequency of electric power and the resonance frequency of the primary side resonance unit are changed, variably controlled.

  According to this invention, by providing the primary side impedance conversion part, the impedance which looked at the primary side resonance part from the output terminal of AC power supply can be made into desired impedance. Further, by changing the resonance frequency of the primary side resonance unit, the resonance frequency of the primary side resonance unit can be brought close to the resonance frequency of the secondary side resonance unit. As a result, it is possible to suppress a decrease in transmission efficiency due to different specifications.

  In such a configuration, when the resonance frequency of the primary side resonance unit is changed, the impedance of the primary side resonance unit viewed from the output end of the AC power supply may deviate from a desired impedance. On the other hand, when the resonance frequency of the primary side resonance unit is changed, the impedance of the primary side resonance unit viewed from the output end of the AC power supply is variably controlled by controlling the impedance of the primary side impedance conversion unit. Can be set to a desired impedance. Thereby, it is possible to cope with the difference in specifications while setting the impedance of the primary-side resonance unit viewed from the output end of the AC power supply as a desired impedance.

  According to a second aspect of the present invention, in a power receiving device capable of receiving the AC power in a contactless manner from a power transmitting device having a primary side resonance unit to which AC power is input, the AC power is received from the primary side resonance unit. A secondary side resonance unit, a load, and a secondary side impedance conversion unit provided between the secondary side resonance unit and the load, the impedance of which is variably configured, and the secondary side The resonance frequency of the resonance unit can be changed, and the impedance of the secondary side impedance conversion unit is variably controlled when the resonance frequency of the secondary side resonance unit is changed.

  According to this invention, the impedance from the output end of the secondary side resonance unit to the load can be set to a desired impedance by providing the secondary side impedance conversion unit. Further, by changing the resonance frequency of the secondary side resonance unit, the resonance frequency of the secondary side resonance unit can be brought close to the resonance frequency of the primary side resonance unit. As a result, it is possible to suppress a decrease in transmission efficiency due to different specifications.

  In such a configuration, when the resonance frequency of the secondary side resonance unit is changed, the impedance from the output end of the secondary side resonance unit to the load may deviate from a desired impedance. In contrast, when the resonance frequency of the secondary side resonance unit is changed, the impedance from the output end of the secondary side resonance unit to the load is variably controlled by variably controlling the impedance of the secondary side impedance conversion unit. The impedance can be as follows. Thereby, it is possible to cope with the difference in specifications while making the impedance from the output end of the secondary side resonance unit to the load a desired impedance.

  According to a third aspect of the present invention, in the non-contact power transmission apparatus, the power transmission device according to the first aspect and the power receiving device according to the second aspect are provided. According to this invention, there exists an effect mentioned above in a non-contact electric power transmission apparatus.

  According to a fourth aspect of the present invention, both of the impedance of the primary side impedance conversion unit and the impedance of the secondary side impedance conversion unit are the resonance frequency of the primary side resonance unit and the frequency of the AC power, and the 2 The control is variably controlled when at least one of the resonance frequency of the secondary side resonance unit is changed. When any one of the resonance frequency of the primary side resonance unit and the frequency of the AC power and the resonance frequency of the secondary side resonance unit is changed, the impedance from the output end of the AC power source to the load and the secondary side It is assumed that both the impedance from the output end of the resonance unit to the load deviate from the desired impedance. On the other hand, according to the present invention, by variably controlling both the impedances of the respective impedance conversion units, the impedance from the output end of the AC power supply to the load is set to a desired impedance, and the secondary side resonance unit The impedance from the output end to the load can be set to a desired impedance. Therefore, it is possible to suitably follow the frequency change.

  According to this invention, in the configuration in which the impedance conversion unit is provided, it is possible to suitably cope with a difference in specifications.

The block diagram which shows the electrical constitution of the non-contact electric power transmission apparatus which concerns on this invention. The circuit diagram of a non-contact electric power transmission apparatus. The circuit diagram of the non-contact electric power transmission apparatus of another example.

A non-contact power transmission apparatus (non-contact power transmission system) according to the present invention 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 capable of outputting sinusoidal high frequency power using system power. Specifically, the high frequency power supply 12 includes a rectifier 12a that rectifies system power into DC power, and a DC / DC converter 12b that converts a voltage value of the DC power. The high-frequency power source 12 includes a DC / RF converter 12c that generates high-frequency power of a rectangular wave using the DC power output from the DC / DC converter 12b, and a rectangle generated by the DC / RF converter 12c. A low-pass filter 12d for shaping the high-frequency power of the wave into the high-frequency power of the sine wave. In the following description, the sinusoidal high-frequency power is simply referred to as high-frequency power.

  Incidentally, the high frequency power supply 12 is configured to be able to output high frequency power having different power values. Specifically, the DC / DC converter 12b includes a switching element that is periodically turned on / off (switched). The high frequency power supply 12 is configured to output high frequency power having a power value corresponding to the duty ratio of on / off of the switching element.

  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 a 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 a power transmitter 13 (primary side resonance unit) provided in the ground side device 11. And a power receiver 23 (secondary resonance unit) provided in the vehicle-side device 21.

  The power transmitter 13 is composed of a resonant circuit including a primary coil 13a and a primary capacitor 13b connected in parallel. The resonance frequency of the power transmitter 13 is set to be the same as the frequency of the high frequency power output from the high frequency power supply 12 (hereinafter simply referred to as the output frequency). The power receiver 23 is composed of a resonance circuit including a secondary coil 23a and a secondary capacitor 23b connected in parallel.

  According to this configuration, if the resonance frequency of the power transmitter 13 and the resonance frequency of the power receiver 23 are the same or within a range in which magnetic field resonance is possible, when high-frequency power is input from the high-frequency power source 12 to the power transmitter 13, The power transmitter 13 and the power receiver 23 perform 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 includes a rectifier 24, a DC / DC converter 25, and a vehicle battery 26 as a load 22. The rectifier 24 includes a diode that operates at a threshold voltage value, and rectifies the high-frequency power received by the power receiver 23 into DC power. The DC / DC converter 25 has a switching element that is periodically turned on / off (switched), and converts the voltage value of the DC power rectified by the rectifier 24 into a different voltage value by switching of the switching element. The vehicle-side device 21 includes a detection sensor 27 that detects the charge amount of the vehicle battery 26, and the charge amount can be grasped by the detection sensor 27.

Incidentally, the impedance of the vehicle battery 26 varies depending on the power value of the input DC power. For this reason, the load 22 is a variable load in which the impedance ZL varies.
As shown in FIG. 1, the ground side device 11 is provided with a power source side controller 14 for controlling a high frequency power source 12, specifically, a DC / DC converter 12 b and a DC / RF converter 12 c. Further, the vehicle-side device 21 is provided with a vehicle-side controller 28 that can communicate wirelessly with the power supply-side controller 14, and information can be exchanged between the controllers 14 and 28.

  The non-contact power transmission device 10 includes a plurality of impedance converters 31 and 32. Specifically, the ground-side device 11 includes a first impedance converter 31 as a primary-side impedance converter provided between the high-frequency power source 12 and the power transmitter 13. The vehicle-side device 21 includes a second impedance converter 32 as a secondary impedance converter provided between the power receiver 23 and the load 22.

  As shown in FIG. 2, the first impedance converter 31 includes an inverted L-type LC circuit including a first inductor 31a and a first capacitor 31b. The second impedance converter 32 is configured by an L-type LC circuit including a second inductor 32a and a second capacitor 32b.

  Here, the present inventors have found that the real part of the impedance from the output end of the power receiver 23 to the load 22 contributes to the transmission efficiency between the power transmitter 13 and the power receiver 23. Specifically, it has been found that a specific resistance value Rout having a transmission efficiency relatively higher than other resistance values exists in the real part of the impedance from the output terminal of the power receiver 23 to the load 22. In other words, in the real part of the impedance from the output terminal of the power receiver 23 to the load 22, there is a specific resistance value Rout (second resistance value) at which transmission efficiency is higher than a predetermined resistance value (first resistance value). Found it to exist.

  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 from the power receiver 23 (specifically, the output end of the power receiver 23) to the virtual load X1. When the resistance value of Rb1 is Rb1, 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 power receiver 23 to the load 22 (impedance at the input end of the second impedance converter 32) approaches the specific resistance value Rout (preferably coincident). The impedance ZL of the load 22 is converted. That is, the specific resistance value Rout corresponds to a desired impedance in the impedance from the output end of the power receiver 23 to the load 22.

  Here, the power value of the high frequency power output from the high frequency power supply 12 depends on the impedance from the output end of the high frequency power supply 12 to the load 22, that is, the impedance of the input end of the first impedance converter 31. The impedance from the output end of the high frequency power supply 12 to the load 22 can also be said to be the impedance when the power transmitter 13 side is viewed from the output end of the high frequency power supply 12.

  In such a configuration, in the first impedance converter 31, the impedance from the output end of the power receiver 23 to the load 22 is close to the specific resistance value Rout so that the high-frequency power having a desired power value is output from the high-frequency power source 12. Impedance conversion is performed on the impedance Zin from the input end of the power transmitter 13 to the load 22 in the situation. For example, the power value of the output power of the high-frequency power source 12 required for the power value of DC power input to the vehicle battery 26 of the load 22 to be a power value suitable for charging is set to a power value suitable for charging. Use high-frequency power. Then, the impedance from the output end of the high frequency power supply 12 to the load 22 (impedance at the input end of the first impedance converter 31) for outputting high frequency power having a power value suitable for charging from the high frequency power supply 12 is charged. A suitable input impedance Zt is used. In this case, the first impedance converter 31 has an impedance Zin from the input end of the power transmitter 13 to the load 22 such that the impedance from the output end of the high frequency power supply 12 to the load 22 becomes the input impedance Zt suitable for the charging. The impedance is converted. The input impedance Zt suitable for charging corresponds to a desired impedance in the impedance from the output end of the high frequency power supply 12 to the load 22.

  Next, the case where trouble occurs in power transmission by magnetic field resonance will be described. When the resonance frequency and output frequency of the power transmitter 13 (hereinafter referred to as the ground side frequency together) and the resonance frequency of the power receiver 23 (hereinafter referred to as the vehicle side frequency) are the same, the transmission efficiency is high. Become. On the other hand, if the frequencies differ due to different specifications or the like between the ground side device 11 and the vehicle side device 21, the transmission efficiency may be reduced or power transmission may not be possible.

On the other hand, the ground side device 11 and the vehicle side device 21 have a configuration for correcting a difference in frequency between the two. The configuration will be described in detail below.
As shown in FIGS. 1 and 2, the power transmitter 13 includes a series connection body of a correction capacitor 13c and a switching element 13d. The series connection body is connected in parallel to the primary side capacitor 13b. Thereby, the resonance frequency of the power transmitter 13 can be changed. Further, the DC / RF converter 12c is configured to be able to change the frequency of the high frequency power of the rectangular wave. From the above, the ground side frequency can be changed.

  The cut-off frequency of the low-pass filter 12d is set so as to be able to cope with the change of the output frequency, but is not limited to this, and the power-side controller 14 is configured to be able to change the cut-off frequency of the low-pass filter 12d. May be.

  In addition, although the said serial connection body was one, in fact, two or more are provided. For this reason, by performing switching control of each switching element 13d, a plurality of types of resonance frequencies of the power transmitter 13 and the power receiver 23 can be taken.

  The power supply side controller 14 can change the resonance frequency of the power transmitter 13 by controlling the switching operation of the switching element 13d. Moreover, the power supply side controller 14 can change the frequency of the high frequency electric power of a rectangular wave by controlling the DC / RF converter 12c, and can change an output frequency through this.

  Here, the specific resistance value Rout depends on the resonance frequencies of the power transmitter 13 and the power receiver 23. Further, the impedance Zin from the input end of the power transmitter 13 to the load 22 depends on the output frequency and each resonance frequency. For this reason, if the terrestrial frequency is changed, the transmission efficiency may be reduced, or high-frequency power having a desired power value may not be obtained. On the other hand, the non-contact power transmission device 10 has a configuration for following changes in the ground side frequency. The configuration will be described in detail below. In the following description, it is assumed that the power transmitter 13 and the power receiver 23 are arranged at a predetermined reference position.

  The constant (impedance) of each of the impedance converters 31 and 32 is variable (adjustable) in real part (resistance) and / or imaginary part (reactance). As shown in FIG. 2, in this embodiment, the capacitances of the capacitors 31b and 32b of the impedance converters 31 and 32 are variable. The constant (impedance) can be said to be a conversion ratio, an inductance, or a capacitance.

  Incidentally, the initial state constants of the impedance converters 31 and 32 are set under the condition that the ground side frequency is a predetermined initial frequency and the ground side frequency and the vehicle side frequency are the same. For example, the initial state constant of the second impedance converter 32 converts the impedance ZL of the load 22 into the specific resistance value Rout when the high-frequency power for charging is output from the high-frequency power source 12 under the above conditions. Is set to a value. The initial state constant of the first impedance converter 31 is the impedance from the input end of the power transmitter 13 to the load 22 when the high-frequency power for charging is output from the high-frequency power source 12 under the above conditions. Zin is set to a value that converts the input impedance Zt suitable for charging.

  A primary-side measuring device 41 as a measuring unit is provided between the high-frequency power source 12 and the power transmitter 13, specifically between the high-frequency power source 12 and the first impedance converter 31. The primary side measuring instrument 41 measures a voltage waveform and a current waveform in response to a request from the power supply side controller 14 and transmits the measurement result to the power supply side controller 14.

  Between the power receiver 23 and the load 22, specifically between the power receiver 23 and the second impedance converter 32, a secondary side measuring device 42 as a measuring unit is provided. The secondary side measuring instrument 42 measures the voltage waveform and the current waveform in response to a request from the vehicle side controller 28 and transmits the measurement result to the vehicle side controller 28.

  A fixed resistor (fixed load) 51 having the same resistance value (impedance) is provided between the second impedance converter 32 and the load 22 regardless of the power value of the input high-frequency power. The vehicle-side device 21 is provided with a relay 52 as a switching unit that switches the connection destination of the second impedance converter 32 to the fixed resistor 51 or the load 22. It can be said that the connection destination of the second impedance converter 32 is an output destination of high-frequency power received by the power receiver 23 and output from the second impedance converter 32.

  The controllers 14 and 28 change the ground side frequency and perform variable control of the constants of the impedance converters 31 and 32 in a charging sequence for charging the vehicle battery 26. The charging sequence will be described in detail below. The charging sequence is executed while the controllers 14 and 28 exchange information with each other.

First, each controller 14 and 28 confirms that the power transmitter 13 and the power receiver 23 are disposed at a predetermined reference position through the exchange of information.
Thereafter, each of the controllers 14 and 28 determines whether or not the initial frequency of the ground side frequency matches the vehicle side frequency. Specifically, for example, information regarding the initial frequency of the ground side frequency is stored in the memory of the power supply side controller 14, and information regarding the vehicle side frequency is stored in the memory of the vehicle side controller 28. And each controller 14 and 28 determines whether the initial frequency of a ground side frequency and the vehicle side frequency correspond based on the information regarding the initial frequency of a ground side frequency, and the information regarding the vehicle side frequency.

  If the two match, the controllers 14 and 28 start power transmission as they are. Specifically, the power supply side controller 14 controls the high frequency power supply 12 so that high frequency power for charging is output, and the vehicle side controller 28 relays the connection destination of the second impedance converter 32 to the load 22. 52 is controlled.

  On the other hand, when the initial frequency of the ground side frequency and the vehicle side frequency do not match, the power source side controller 14 causes the high frequency power source 12 and the switching element so that the ground side frequency approaches (preferably matches) the vehicle side frequency. 13d is controlled.

  When the ground-side frequency and the vehicle-side frequency match or approach within a predetermined allowable range due to the change of the ground-side frequency, the vehicle-side controller 28 determines that the connection destination of the second impedance converter 32 is a fixed resistor. The relay 52 is controlled to be 51. Thereafter, the power supply side controller 14 controls the high frequency power supply 12 so that the high frequency power for adjustment whose power value is smaller than the high frequency power for charging is output. And each controller 14 and 28 performs variable control of the constant of each impedance converter 31 and 32. FIG.

  For example, first, the vehicle-side controller 28 performs variable control of the constant of the second impedance converter 32 so as to approach the specific resistance value Rout. In this case, for example, the specific resistance value Rout is specified using various parameters (power value, power factor, etc.) derived from the voltage waveform and current waveform measured by the secondary-side measuring instrument 42.

  After the variable control of the constants of the second impedance converter 32 is completed, the power supply side controller 14 determines that the impedance from the output end of the high frequency power supply 12 to the load 22 approaches the input impedance Zt suitable for the charging. Based on the measurement result of the secondary measuring instrument 41, variable control of the constant of the first impedance converter 31 is performed. That is, after the variable control of the constant of the second impedance converter 32, the variable control of the constant of the first impedance converter 31 is performed.

  After the variable control of the constants of the impedance converters 31 and 32, the power supply controller 14 controls the high frequency power supply 12 so that high frequency power for charging is output. Further, the vehicle-side controller 28 controls the relay 52 so that the connection destination of the second impedance converter 32 is the load 22.

  Here, the resistance value (impedance) Rx of the fixed resistor 51 is set to be the same as the impedance ZL of the load 22 in a state where high-frequency power for charging is being output. For this reason, even when the relay 52 is switched, the impedance after the output terminal of the second impedance converter 32 is less likely to fluctuate.

  Thereafter, the vehicle-side controller 28 determines whether or not the charge amount of the vehicle battery 26 has reached the full charge amount (end trigger amount) based on the detection result of the detection sensor 27, and when the full charge amount has been reached. Is notified to the power supply side controller 14. Upon receiving the notification, the power supply side controller 14 controls the high frequency power supply 12 to stop the output of the high frequency power.

The operation of this embodiment will be described below.
Since the second impedance converter 32 performs impedance conversion so that the impedance from the output end of the power receiver 23 to the load 22 becomes the specific resistance value Rout, the transmission efficiency is improved.

  Further, since the first impedance converter 31 performs impedance conversion so that the impedance from the output end of the high-frequency power source 12 to the load 22 becomes the input impedance Zt suitable for charging, the first impedance converter 31 has high-frequency power having a power value suitable for charging. Is supplied to the load 22.

  Here, when the vehicle-side frequency and the ground-side frequency are different, the ground-side frequency is changed so that they are close to each other. Thereby, even if it is a case where both are different frequencies, while being able to transmit electric power, the fall of transmission efficiency is suppressed.

  In such a configuration, the specific resistance value Rout and the impedance Zin from the input end of the power transmitter 13 to the load 22 vary with the change of the ground side frequency. Corresponding to this variation, the constants of the impedance converters 31 and 32 are variably controlled. As a result, a decrease in transmission efficiency associated with the change in the ground frequency is suppressed.

According to the embodiment described in detail above, the following excellent effects are obtained.
(1) In the configuration in which the ground-side device 11 is provided with the first impedance converter 31 having a variable constant (impedance), the ground-side frequency can be changed, and the ground-side frequency is changed. The variable control of the constant of the first impedance converter 31 is performed. Thereby, by making the ground side frequency close to the vehicle side frequency, the impedance from the output terminal of the high frequency power supply 12 to the load 22 is reduced to a desired impedance (without realizing non-contact power transmission and a reduction in transmission efficiency). The input impedance Zt suitable for charging can be obtained.

  In particular, the power supply side controller 14 performs variable control of the constant of the first impedance converter 31 in response to the change of the ground side frequency, so that the output end of the high frequency power supply 12 can be used regardless of the change of the ground side frequency. The impedance up to the load 22 is set to the input impedance Zt suitable for charging. That is, the power supply side controller 14 performs variable control of the constant of the first impedance converter 31 so that the impedance of the load 22 approaches a constant value regardless of the change of the ground side frequency from the output end of the high frequency power supply 12. did. Thereby, the stable electric power supply is implement | achieved.

  (2) Further, when the ground side frequency is changed, not only the first impedance converter 31 provided on the side where the frequency is changed (the ground side device 11) but also the side where the frequency is changed. It was set as the structure which also performs variable control of the constant of the 2nd impedance converter 32 provided in the different side (vehicle side apparatus 21). Thereby, it can suppress that the impedance from the output terminal of the power receiver 23 to the load 22 shifts from a desired impedance (specific resistance value Rout) with the change of the ground side frequency, and maintains high transmission efficiency. Can do.

  (3) When the ground frequency is changed and the constant control of the constants of the impedance converters 31 and 32 is performed, the connection destination of the second impedance converter 32 is the fixed resistor 51. Thereby, the variable control of the constant of each impedance converter 31 and 32 can be performed easily.

  Specifically, if the ground frequency is changed in a situation where the second impedance converter 32 and the load 22 are connected, the power value of the high-frequency power input to the load 22 varies with the change. Can do. In this case, the impedance ZL of the load 22 varies. Therefore, each of the impedance converters 31 and 32 needs to cope with the fluctuation of the impedance ZL of the load 22 in addition to the specific resistance value Rout and the fluctuation of the impedance Zin from the input end of the power transmitter 13 to the load 22. The constant variable control becomes complicated.

  On the other hand, according to the present embodiment, since the resistance value Rx of the fixed resistor 51 is constant, the variable control of the constants of the impedance converters 31 and 32 can be performed without considering the fluctuation of the impedance ZL of the load 22. As a result, the variable control of the constants of the impedance converters 31 and 32 can be easily performed.

  (4) After the change of the ground side frequency or the like is completed, the connection destination of the second impedance converter 32 is the load 22. When the second impedance converter 32 is connected to the fixed resistor 51, the adjustment high-frequency power having a power value smaller than the charging high-frequency power is output, and the second impedance converter 32 is connected to the load 22. When connected to the high frequency power source 12, the high frequency power source 12 was controlled so that high frequency power for charging was output. Thereby, it is possible to suppress power loss that may occur when variable control of the constants of the impedance converters 31 and 32 is performed.

  In particular, when high frequency power for charging having a relatively high power value is output from the high frequency power supply 12 in a situation where the ground side frequency is changed, the impedance from the output end of the high frequency power supply 12 to the load 22 is determined from the desired impedance. Due to the deviation, an excessive load may be applied to the high-frequency power source 12 or the like. On the other hand, in the variable control of the constants of the impedance converters 31 and 32 after the ground side frequency is changed, the high frequency power for adjustment having a relatively small power value is output from the high frequency power source 12. The burden on the high frequency power source 12 and the like can be reduced.

In addition, you may change the said embodiment as follows.
In embodiment, it was the structure which changes a ground side frequency, However, It is not restricted to this, It is good also as a structure which changes a vehicle side frequency. For example, as shown in FIG. 3, the power receiver 23 includes a series connection body of a correction capacitor 23c and a switching element 23d. The series connection body is connected in parallel to the secondary capacitor 23b. The vehicle-side controller 28 can change the resonance frequency of the power receiver 23 by controlling the switching element 23d.

  In such a configuration, when the ground-side frequency and the vehicle-side frequency are different, the vehicle-side frequency is changed so that they approach (preferably coincide). And each controller 14 and 28 performs variable control of the constant of each impedance converter 31 and 32 after the change of the vehicle side frequency. In this case, the control can be facilitated because the ground frequency need not be changed. However, there is a concern that the size of the power receiver 23 may be increased by the space for installing the configuration for changing the vehicle-side frequency, and the vehicle-side device 21 installed in the vehicle is more installed space. It is preferable to change the ground side frequency in view of the point that it is difficult to secure the frequency.

In addition, it may be configured to change both the ground side frequency and the vehicle side frequency.
In the embodiment, the switching frequency of the switching element 13d is controlled to change the resonance frequency of the power transmitter 13. However, the present invention is not limited to this, and a variable capacitor is used instead of the primary capacitor 13b. The resonance frequency of the power transmitter 13 may be changed by the side controller 14 variably controlling the capacitance of the variable capacitor. Needless to say, in order to change the resonance frequency, the inductance may be variably controlled instead of the capacitance, or both the capacitance and the inductance may be variably controlled.

  In the embodiment, the configuration is such that both the constant of the first impedance converter 31 and the constant of the second impedance converter 32 are variably controlled in accordance with the change of the ground side frequency. For example, when the ground side frequency is changed, only the constant of the first impedance converter 31 may be variably controlled. Further, when changing the vehicle-side frequency, the constant control of the constant of the second impedance converter 32 may be performed, and the variable control of the constant of the first impedance converter 31 may not be performed. In short, any configuration may be used as long as the constant of the impedance converter provided on the frequency changing side is variably controlled.

  In the embodiment, the power supply side controller 14 changes the ground side frequency and performs variable control of the constants of the first impedance converter 31. However, the present invention is not limited to this. For example, separately from the power supply side controller 14, A dedicated circuit for performing variable control of the constant of the first impedance converter 31 may be provided.

  In the embodiment, a difference in frequency is assumed as a difference in specifications between the ground-side device 11 and the vehicle-side device 21, but the present invention is not limited to this, and for example, a difference in power transmission method may be assumed. Specifically, for example, when one of the power transmitter and the power receiver is an electromagnetic induction type resonance unit and the other is a magnetic resonance type resonance unit, power transmission is performed by the magnetic field resonance method. One side may be adjusted. Even in this case, the present invention can be applied.

  As a specific configuration for “adjusting one side so that power transmission is performed by the magnetic field resonance method”, for example, a variable capacitor that forms a resonance circuit in cooperation with a coil used in the electromagnetic induction method is provided. A configuration is conceivable in which the resonance frequency is changed by variably controlling the capacitance of the variable capacitor. In addition, when the difference of the said power transmission system is assumed, it is good for each controller 14 and 28 to determine whether a power transmission system corresponds through the exchange of information mutually.

  ○ Regarding the change of the ground side frequency, it is not necessary that the ground side frequency and the vehicle side frequency be completely the same, and they may be shifted within a range that does not hinder power transmission. In short, what is necessary is just the structure which changes at least one of both so that a vehicle side frequency and a ground side frequency may approach.

○ If the ground frequency and the vehicle frequency are not within the allowable range even if the ground frequency is changed, the charging sequence may be stopped.
In embodiment, although the power transmission device 13 and the power receiving device 23 were arrange | positioned in the reference position, it is not restricted to this, You may shift | deviate from a reference position. In this case, variable control of the constants of the impedance converters 31 and 32 may be performed in accordance with fluctuations in the relative positions of the power transmitter 13 and the power receiver 23. Thereby, using each impedance converter 31 and 32, it can respond to both the change of a frequency, and the fluctuation | variation of the relative position of the power transmission device 13 and the power receiving device 23. FIG.

  In the embodiment, each of the impedance converters 31 and 32 is configured by an LC circuit, but is not limited thereto. For example, instead of the first impedance converter 31, a transformer is configured in cooperation with the primary side coil 13 a and a primary side induction coil having a variable inductance is provided. It is good also as a structure which transmits electric power between the electric appliances 13 by electromagnetic induction. In this case, the inductance of the primary induction coil may be set so that the primary induction coil functions as the first impedance converter 31.

  Similarly, a transformer is formed between the power receiver 23 and the secondary side measuring device 42 in cooperation with the secondary side coil 23a instead of the second impedance converter 32, and the inductance is variable. A secondary induction coil may be provided, and power may be transmitted between the power receiver 23 and the secondary induction coil by electromagnetic induction. In this case, the inductance of the secondary induction coil may be set so that the secondary induction coil operates as the second impedance converter 32.

○ At least one impedance converter of each of the impedance converters 31 and 32 may be replaced with a transformer.
(Circle) the 1st impedance converter 31 may impedance-convert the impedance Zin from the input terminal of the power transmission device 13 to the load 22 so that a power factor may be improved.

  The first impedance converter 31 may be omitted. In addition to the first impedance converter 31, the ground side device 11 may be provided with an impedance converter that improves the power factor.

  O The resistance value Rx of the fixed resistor 51 may be set arbitrarily. In this case, when the connection destination of the second impedance converter 32 is switched from the fixed resistor 51 to the load 22, the variable control of the constant of the second impedance converter 32 may be performed again.

In the embodiment, the power value is different between the high-frequency power for adjustment and the high-frequency power for charging. However, the power value is not limited to this, and both power values may be set to be the same.
In addition, in a situation where the connection destination of the second impedance converter 32 is the fixed resistor 51, the high-frequency power for charging is output from the high-frequency power supply 12, and the impedance converters 31 and 32 are in that state. It may be configured to perform variable control of the constants.

The specific structure of each impedance converter 31 and 32 is not limited to the thing of the said embodiment, It is arbitrary. For example, a π type, a T type, or the like may be used.
The voltage waveform of the high-frequency power output from the high-frequency power source 12 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, 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 load 22 includes the rectifier 24 and the vehicle battery 26, but is not limited thereto, and may include other electronic devices. Moreover, you may employ | adopt as a load what has fixed impedance irrespective of the electric power value of the input electric power.

  In the embodiment, the main body that controls the relay 52 is the vehicle-side controller 28, but is not limited thereto, and may be the power-side controller 14, for example. Further, the main body of the control of the high frequency power supply 12 is not limited to the power supply side controller 14 and may be, for example, the vehicle side controller 28. Similarly, the control subject of each impedance converter 31 and 32 is arbitrary.

In the embodiment, the high-frequency power source 12 is provided, but the present invention is not limited to this, and may be omitted.
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. In this case, the resonant circuit is configured to receive high frequency power from the primary side coupling coil by electromagnetic induction. Similarly, the power receiver 23 includes a resonance circuit including a secondary side coil 23a and a secondary side capacitor 23b, and a secondary side coupling coil coupled to the resonance circuit by electromagnetic induction. The power may be taken out from the resonance circuit of the power receiver 23 by using it.

The high frequency power supply 12 may be any of a power source, a voltage source, and a current source.
A power source may be adopted as the high-frequency power source 12, and the impedance converters 31 and 32 may be used for impedance matching. Specifically, the first impedance converter 31 has an impedance Zin from the input end of the power transmitter 13 to the load 22 so that the impedance from the output end of the high frequency power supply 12 to the load 22 matches the output impedance of the high frequency power supply 12. May be impedance-converted. The second impedance converter 32 converts the impedance ZL of the load 22 to impedance conversion so that the impedance from the output terminal of the power receiver 23 to the load 22 matches the impedance from the output terminal of the power receiver 23 to the high frequency power supply 12. You may do.

  In such a configuration, the primary side measuring device 41 measures the reflected wave power from the power transmitter 13 toward the high frequency power source 12, and the secondary side measuring device 42 reflects from the second impedance converter 32 toward the high frequency power source 12. It is good also as a structure which measures wave power. And each controller 14 and 28 is good to perform the variable control of the constant of each impedance converter 31 and 32 so that each reflected wave electric power may become small. Moreover, in the said structure, it is good to variably control the constant of each impedance converter 31 and 32 simultaneously.

  In the case of the above configuration, the impedance matching the output impedance of the high frequency power supply 12 corresponds to a desired impedance in the impedance from the output end of the high frequency power supply 12 to the load 22. The impedance that matches the impedance from the output end of the power receiver 23 to the high-frequency power supply 12 corresponds to a desired impedance in the impedance from the output end of the power receiver 23 to the load 22.

  The power value of the high-frequency power output from the high-frequency power source 12 may be changed while the vehicle battery 26 is being charged. In this case, the impedance ZL of the load 22 may be made constant by adjusting the on / off duty ratio of the switching element of the DC / DC converter 25 in accordance with the fluctuation of the impedance of the vehicle battery 26. In this case, the vehicle battery corresponds to “load or variable load”, and the DC / DC converter corresponds to “secondary impedance converter”. The adjustment of the duty ratio can be said to be the adjustment of the impedance of the DC / DC converter. That is, the “load” is input with high-frequency power received by the secondary coil 23a or DC power rectified therefrom.

  A third impedance converter may be separately provided between the relay 52 and the load 22. In this case, the relay 52 switches the connection destination of the second impedance converter 32 to the fixed resistor 51 or the third impedance converter connected to the load 22. In such a configuration, the constant of the third impedance converter is variably controlled in accordance with the change in the power value of the high frequency power output from the high frequency power supply 12, so that the input terminal of the third impedance converter can be used. It is preferable that the impedance to the load 22 be constant.

  In addition, the configuration is not limited to the configuration in which two impedance converters are provided in the vehicle side device 21 as described above, and three or more impedance converters may be provided in the vehicle side device 21. Similarly, two or more impedance converters may be provided in the ground side device 11.

Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.
(A) In the real part of the impedance from the output end of the secondary side resonance unit to the load, there is a specific resistance value that has a relatively higher transmission efficiency than other resistance values,
3. The power receiving device according to claim 2, wherein the secondary side impedance conversion unit performs impedance conversion so that an impedance from an output terminal of the secondary side resonance unit to the load approaches the specific resistance value.

  (B) When a virtual load having a resistance value Ra1 is provided at the input end of the primary side resonance unit and the resistance value from the secondary side resonance unit to the virtual load is Rb1, the specific resistance value is √ The power receiving device according to the technical idea (A), which is (Ra1 × Rb1).

(C) The load is a variable load whose impedance varies according to the power value of the input power,
A fixed load provided separately from the variable load and having the same impedance regardless of the power value of the input power;
A switching unit that switches the output destination of the AC power received by the secondary side resonance unit and output from the secondary impedance conversion unit to the fixed load or the variable load;
With
When the resonance frequency of the secondary side resonance unit is changed, the switching unit receives the power at the secondary side resonance unit and outputs the AC power output from the secondary side impedance conversion unit as described above. The power receiving device according to claim 2, wherein the power receiving device is a fixed load, and the technical thoughts (a) and (b).

  DESCRIPTION OF SYMBOLS 10 ... Non-contact electric power transmission apparatus, 11 ... Ground side apparatus (power transmission apparatus), 12 ... High frequency power supply, 13 ... Power transmitter (primary side resonance part), 13c ... Correction capacitor, 13d ... Switching element, 14 ... Power supply side controller , 21 ... Vehicle side device (power receiving device), 22 ... Load (variable load), 23 ... Power receiver (secondary side resonance unit), 26 ... Vehicle battery, 28 ... Vehicle side controller, 31 ... First impedance converter (Primary side impedance converter), 32 ... second impedance converter (secondary side impedance converter), 41, 42 ... measuring instrument, 51 ... fixed resistor (fixed load), 52 ... relay.

Claims (4)

AC power supply capable of outputting AC power,
A primary-side resonating unit to which the AC power is input;
In a power transmission device capable of transmitting the AC power in a non-contact manner with respect to a power receiving device having a secondary side resonance unit,
A primary-side impedance converter provided between the AC power source and the primary-side resonating unit and having a variable impedance;
The frequency of the AC power output from the AC power source and the resonance frequency of the primary side resonance unit can be changed,
The impedance of the primary side impedance conversion unit is variably controlled when the frequency of the AC power output from the AC power source and the resonance frequency of the primary side resonance unit are changed. . In a power receiving device capable of receiving the AC power in a non-contact manner from a power transmitting device having a primary side resonance unit to which AC power is input,
A secondary side resonance part capable of receiving the AC power from the primary side resonance part;
Load,
A secondary-side impedance conversion unit provided between the secondary-side resonance unit and the load and configured to have variable impedance;
With
The resonance frequency of the secondary side resonance unit can be changed,
The impedance of the secondary side impedance conversion unit is variably controlled when the resonance frequency of the secondary side resonance unit is changed. A power transmission device according to claim 1;
The power receiving device according to claim 2;
A non-contact power transmission device comprising:   Both the impedance of the primary side impedance conversion unit and the impedance of the secondary side impedance conversion unit are the resonance frequency of the primary side resonance unit and the frequency of the AC power, and the resonance frequency of the secondary side resonance unit. The non-contact power transmission apparatus according to claim 3, wherein the control is variably controlled when at least one of them is changed.