JP2011142769A - Method and device for transmitting magnetic resonance power - Google Patents

Abstract

An object of the present invention is to efficiently realize non-contact power transmission using a coil by self-resonance.
A power receiving device includes a frequency characteristic detecting device that detects a frequency characteristic of received power from a power receiving coil, and power frequency information including a frequency characteristic or a maximum power frequency at which the received power obtained from the frequency characteristic is maximized. Is transmitted to the power transmission device. The power transmission device includes a power transmission frequency variable device that can vary the frequency of the transmitted power, a frequency scanning device that sequentially changes the frequency of the transmitted power transmitted from the power transmission coil, and reception that receives power frequency information transmitted from the transmission device. Have the device. Based on the power frequency information received by the receiving device, a frequency control device that matches the frequency of the transmitted power by the transmission frequency variable device with the detected maximum power frequency is provided.
[Selection] Figure 1

Description

  The present invention relates to a wireless power transmission method and a power transmission device by magnetic resonance using a power transmission coil and a power reception coil. It can be used for power transmission for power supply to a battery of an electric vehicle.

  The non-contact power transmission system is roughly classified into the following two systems. The first is power transmission by non-radiation, and the second is power transmission by radiation. The first method mainly includes an electromagnetic induction method using a frequency of several kHz or less using the principle of a transformer, and a near-field electromagnetic (static energy accumulated in the near field) using a frequency of about several tens of MHz. There is an electromagnetic field coupling method by resonance. The second method includes a method using microwave power transmission and a method using laser power transmission. The present invention relates to an electromagnetic resonance method using electromagnetic resonance.

  As electric power transmission using an electromagnetic induction method, techniques of Patent Documents 1 and 2 below are known. The technique of Patent Document 1 discloses a device that transmits power in a non-contact manner using a pair of power coils of a power transmission coil and a power reception coil separated by 5 to 10 mm for power transmission from a fixed part to a rotating part. Yes. According to the document, a frequency power of several hundred kHz is transmitted from the fixed unit to the rotating unit, and the detection signals of various sensors installed in the rotating unit are transmitted by a pair of data coils provided outside the power coil. The signal is transmitted with a signal of several MHz from to the fixed part. Moreover, since the input impedance of the power transmission coil of the fixed portion changes depending on the distance between the power transmission coil and the power reception coil, the frequency of the power supplied to the power transmission coil can be changed in order to improve the power feeding efficiency to the power transmission coil. Has been done. Patent Document 2 also discloses a device that supplies wireless power from a primary coil, receives power by a secondary coil that is electromagnetically coupled to the primary coil, and charges a battery connected to the secondary coil. The technique of this document is a technique for shielding a magnetic field generated by a secondary coil.

  As an electromagnetic field coupling method using electromagnetic resonance, a technique disclosed in the following Non-Patent Document 1 which has recently been attracting attention is known. The technique of the non-patent document 1 discloses a technique capable of transmitting a 9.9 MHz sine wave power using a pair of strongly magnetically coupled magnetic resonance coils having a radius of 25 cm and spaced apart by about 2 m. .

JP-A-8-340285 JP 2009-268334 A

Wireless Power Transfer via Strongly Coupled Magnetic Resonances, Andre Kurs, et.al, Science Vol.317, 6 July 2007

  The methods disclosed in Patent Documents 1 and 2 are systems in which a resonance circuit is provided outside the coil, and the Q value is small, so that efficient power transmission cannot be performed. Since this method is essentially an electromagnetic induction method, in principle, it is a technique for increasing the coupling coefficient, and the distance between the two coils must be narrowed to about 5 to 10 mm. In addition, there is a problem that the transmission efficiency has to be low. In addition, when the distance is 10 mm or more, not only efficient transmission is possible, but also the input impedance of the power transmission coil changes, so adjustment of the power transmission frequency is necessary. Moreover, in these power transmission systems, since an external resonance circuit is used, the resonance characteristics are unimodal.

  On the other hand, the technology disclosed in Non-Patent Document 1 of the electromagnetic field coupling method, in principle, uses a self-resonant type coil to perform electromagnetic field resonance by near-field energy as a whole of the power transmission coil and the power reception coil. This is a wireless power transmission system with high transmission efficiency because, in principle, the Q value is high, transmission over a relatively long distance is possible, and there is no radiation loss. In addition, because of the use of electromagnetic resonance, high transmission efficiency can be achieved even if the coupling coefficient is small (in principle, close to 0) if the frequency and the self-inductance of the transmitting coil and receiving coil are large. can do. As a result, according to Non-Patent Document 1, a power transmission efficiency of 90% or more can be realized even if both power coils are separated by about 1 m. The frequency characteristic of this resonance shows a bimodal characteristic.

  However, when transmitting a large amount of power using the technique of Non-Patent Document 1, if the distance between the power transmission coil and the power reception coil changes, the two resonance frequencies that increase the transmission efficiency change, and the frequency of the transmission power is changed. Even when the optimum frequency is set for the transmission efficiency, if the distance between the two coils is increased, the transmission efficiency is lowered.

  The present invention has been made to solve this problem, and is to always obtain the maximum power transmission efficiency even if the distance between the power transmission coil and the power reception coil changes.

  According to a first aspect of the present invention, there is provided a magnetic resonance power transmission method in which a power transmission coil by self-resonance and a power reception coil by self-resonance are coupled to wirelessly transmit power from the power transmission coil to the power reception coil by magnetic resonance. A magnetic resonance power transmission method is characterized in that a maximum power frequency at which received power is maximized is detected, and the power is transmitted by matching the frequency of the transmitted power by the power transmission coil with the maximum power frequency.

  In the present invention, self-resonant coils are used as the power transmission coil and the power reception coil. The resonance characteristic has a bimodal characteristic having peaks at two resonance frequencies. This method can be used for such a method of charging a battery or the like by transmitting power from the power transmission coil, receiving the power reception coil, and the like. When the distance between the power transmission coil and the power reception coil becomes longer, the two resonance frequencies change in the resonance characteristics, and the two resonance frequencies approach each other. As a result, when power is transmitted at a fixed transmission frequency, power transmission efficiency decreases. Therefore, the frequency at which the power received by the power receiving coil takes the maximum value is detected as the maximum power frequency. And the frequency of the electric power sent out from a power transmission coil is controlled so that it may correspond to the maximum electric power frequency. As a result, the maximum power transmission efficiency can always be achieved regardless of the distance between the power transmission coil and the power reception coil.

  In the present invention, the method of matching the frequency of the transmitted power with the maximum power frequency is such that the frequency of the power transmitted from the power transmission coil is sequentially changed and the power is received by the power receiving coil as in the second aspect. The frequency characteristic of the received power is detected, and the power frequency information including the maximum power frequency at which the received power obtained from the frequency characteristic or the frequency characteristic is maximized is fed back to the power transmission coil side. The method of determining the transmission frequency according to the above can be preferably adopted.

  That is, the frequency of the electric power transmitted from the power transmission coil is scanned, and the frequency characteristic of the received power is detected by the power reception coil. The maximum power frequency may be detected from the peak in the frequency characteristics on the device side where the power receiving coil is installed, and the maximum power frequency may be transmitted to the device side where the power transmission coil is installed. . Further, the frequency characteristic may be transmitted to the device side where the power transmission coil is installed, and the frequency at which the power reaches the maximum value may be detected as the maximum power frequency on the device side.

  Further, as in the third invention, the power transmitted from the power transmission coil is transmitted as a wideband frequency including the maximum power frequency, the power is received by the power reception coil, and the time change characteristic of the power is detected, or A frequency characteristic is detected by frequency analysis of the time change characteristic, and the time change characteristic, the frequency characteristic, or a frequency characteristic by the frequency analysis is detected, and power is obtained from the time change characteristic, the frequency characteristic, or the frequency characteristic. The power frequency information including the maximum power frequency that maximizes the power may be fed back to the power transmission coil side to determine the power transmission frequency by the power transmission coil. As the broadband frequency including the maximum power frequency, a broadband frequency including the frequency of at least one of the two peaks in the resonance characteristics is selected. Of course, a wideband frequency including two peak frequencies may be selected. As this wide band power, for example, a pulse and a square wave are power. The received power of the transmitted power becomes an impulse response of the system from the power transmitting coil and the power receiving coil. Therefore, the transfer function of the system, that is, the frequency characteristic can be obtained from the time characteristic of the received power by Fourier transform. This frequency characteristic may be obtained on the side where the power transmission coil is installed, or may be obtained on the side where the power reception coil is installed. Therefore, the type of information transmitted from the power receiving coil to the power transmitting coil varies depending on how much data is processed on the power receiving coil side. When transmitting to the power transmission coil side with the time characteristics, the frequency characteristics are obtained by Fourier transform from the time characteristics on the power receiving coil side, and when the frequency characteristics are transmitted to the power transmission coil side, the frequency characteristics are measured on the power receiving coil side. Further, there are three ways of obtaining the maximum power frequency and transmitting the maximum power frequency to the power transmission coil side. On the power transmission coil side, data processing is performed according to the type of received power frequency information, and the maximum power frequency is finally detected.

  The power for obtaining the maximum power frequency may be the main transmission power for supplying power to the device in which the power receiving coil is installed, or may be test transmission power that is smaller than the main transmission power. That is, the fourth invention is characterized in that the test transmission power for detecting the maximum power frequency is smaller than the main transmission power transmitted in accordance with the maximum power frequency.

  Further, the feedback of the power frequency information may be performed by a transmission antenna and a reception antenna of different systems for the power transmission coil and the power reception coil as in the fifth invention. Further, as in the sixth invention, the feedback of the power frequency information may be performed by transmitting the information from the power receiving coil to the power transmitting coil.

  The seventh invention includes a power transmission coil by self-resonance, a power transmission device for supplying transmission power to the power transmission coil, a power reception coil by self-resonance electromagnetically coupled to the power transmission coil, and input power from the power reception coil to a load. In a magnetic resonance power transmission device having a power receiving device that supplies power, the power receiving device includes a frequency characteristic detection device that detects a frequency characteristic of the received power from a power receiving coil, and a frequency characteristic or received power obtained from the frequency characteristic. A transmission device that transmits power frequency information including a maximum maximum power frequency to the power transmission device, and the power transmission device includes a power transmission frequency variable device capable of changing a frequency of the transmission power, and a transmission power transmitted from the power transmission coil. A frequency scanning device that sequentially changes the frequency of the power, a receiving device that receives power frequency information transmitted from the transmitting device, and a receiving device. When the received power frequency information is frequency characteristics, the maximum power frequency at which the received power is maximum is detected, and the frequency of the transmission power by the transmission frequency variable device is determined based on the maximum power frequency. A frequency control device that matches the frequency and, when the power frequency information is the maximum power frequency, based on the maximum power frequency, a frequency control device that matches the frequency of the transmission power by the transmission frequency variable device to the maximum power frequency It is characterized by that.

  The present invention is an apparatus invention for carrying out the first and second method inventions. In order to measure the frequency characteristics of the received power, it is desirable that the power transmission device has a frequency scanning device that sequentially changes the frequency of the power transmitted from the power transmission coil, as in the eighth invention.

  The eighth invention is a self-resonant power transmission coil, a power transmission device that supplies transmission power to the power transmission coil, a self-resonance power reception coil that is electromagnetically coupled to the power transmission coil, and power input from the power reception coil. In a magnetic resonance power transmission device having a power receiving device for supplying power to a load, the power receiving device detects a time-varying characteristic of the received power from the power receiving coil or detects a frequency characteristic by frequency analysis of the time-varying characteristic. A frequency characteristic detection apparatus that performs time variation characteristics, frequency characteristics, or a transmission apparatus that transmits power frequency information including a maximum power frequency that maximizes received power obtained from the frequency characteristics to the power transmission apparatus, The power transmission device includes a power transmission frequency variable device that can vary the frequency of the transmitted power, and a broadband frequency that includes the maximum power frequency for the power transmitted from the power transmission coil. If the broadband power output device to be transmitted, the receiving device that receives the power frequency information transmitted from the transmitting device, and the power frequency information received by the receiving device are time-varying characteristics, the time-varying characteristics The frequency characteristic is obtained from the frequency characteristic, the maximum power frequency is detected from the frequency characteristic, and if it is the frequency characteristic, the maximum power frequency at which the received power is maximized is detected, and the transmission power is determined based on the detected maximum power frequency. If the power frequency information is the maximum power frequency, the frequency of the transmission power by the transmission frequency variable device is matched with the maximum power frequency when the power frequency information is the maximum power frequency. And a frequency control device.

  The present invention is an apparatus invention for carrying out the first and third method inventions. It is characterized in that power of a broadband frequency including at least one of the maximum power frequencies is transmitted, and the maximum power frequency is obtained from the received power from the time change characteristics.

  Also in the seventh and eighth device inventions, as in the method invention, the power for obtaining the maximum power frequency may be the power itself for supplying power to the power receiving device, but as in the ninth invention. The test transmission power for detecting the wave number characteristic may be smaller than the main transmission power transmitted in accordance with the maximum power frequency, and the test transmission power may be used for frequency scanning.

  In order to transmit the power frequency information to the power transmission device, as in the tenth invention, the power receiving device has a transmission antenna for transmitting the power frequency information to the power transmission device. A receiving antenna for receiving the transmitted power frequency information may be provided, and the power frequency information may be transmitted by the transmitting antenna and the receiving antenna. Further, as in the eleventh aspect, the transmitting antenna may be a power receiving coil, the receiving antenna may be a power transmitting coil, and power frequency information may be transmitted from the power receiving coil and received by the power transmitting coil.

  The timing for determining the maximum power frequency is arbitrary. Once the interval between the power transmission coil and the power receiving coil is determined, if the interval does not change until power transmission is completed, it may be performed once before the start of power transmission. When the interval between the power transmission coil and the power reception coil changes even during power transmission, the process determines the maximum power frequency at a predetermined time interval even during power transmission and matches the maximum power frequency with the frequency of the transmitted power. What is necessary is just to perform a process. The present invention can be used in a method and apparatus for charging a battery of an electric vehicle, but can also be used for non-contact power supply to a battery with a mobile computer and other mobile electronic devices.

  According to the method or apparatus of the present invention, regardless of the positional relationship between the power transmission coil and the power receiving coil, the maximum power frequency at which the received power takes the maximum value is detected, and the maximum power frequency is set for the main power transmission. Since the power frequencies are matched, the maximum power transmission efficiency can always be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which showed the whole structure of the specific Example 1 of this invention. The flowchart which showed the process sequence of CPU of the power transmission apparatus. The flowchart which showed the process sequence of CPU of a power receiving apparatus. The characteristic view which showed the frequency characteristic of the electric power received by a power receiving apparatus.

  Hereinafter, specific examples of the present invention will be described with reference to the drawings. However, the present invention is not limited to the examples.

  FIG. 1 shows the overall configuration of the first embodiment. A power transmission device 1 is provided on the power transmission side. The power transmission device 1 has a power transmission coil 10. The power transmission coil 10 includes a power feeding coil 12 that is fed from a power amplifier 20 (power transistor) and a coupling coil 11 that is electromagnetically coupled to the power receiving coil 40. The power receiving side has a power receiving coil 40. The power receiving coil 40 includes a coupling coil 41 that is electromagnetically coupled to the power transmission coil 10, and an output coil 42 that outputs received power from the coupling coil 41 to the outside.

  The power transmission coil 10 and the power reception coil 40 are self-resonant coils. That is, the coupling coil 11 constitutes a series resonance circuit including a mutual inductance magnetically coupled to the coupling coil 41, a leakage inductance, and a capacitance existing between the lines of the coupling coil 11. The coupling coil 41 constitutes a series resonance circuit including a mutual inductance magnetically coupled to the coupling coil 11, a leakage inductance, and a capacitance existing between the lines of the coupling coil 41. A coupling characteristic having two resonance frequencies can be obtained in a state in which the coupling coil 11 and the coupling coil 41 are electromagnetically coupled in the near field. The number of turns of the coupling coils 11 and 41 was 5.25 turns, and the diameter was 60 cm. In this state, there is no radiation of electromagnetic waves. This coil based on self-resonance is described in detail in Non-Patent Document 1 above.

  In the power transmission device 1, a power amplifier 20 that supplies power to the feeding coil 12 is connected. A signal generator 21 is connected to the power amplifier 20, and a power transmission frequency variable device 22 is connected to the signal generator 21. Has been. The power transmission frequency variable device 22 is controlled by the CPU 23. The CPU 23 is composed of a microcomputer having a memory and an input / output interface. A receiving device 24 for inputting data from the receiving antenna 25 is connected to the CPU 23. The receiving antenna 25 receives data (power frequency information) from the transmitting antenna 55 on the power receiving side.

  A power receiving device 2 is disposed on the power receiving side. In the power receiving device 2, a power receiving device (power transistor) 50 for inputting electric power from the output coil 42 is connected. The power receiving device 50 includes a rectifier circuit and a battery connected to the rectifier circuit. A load 51 is connected. A changeover switch 56 is provided between the power receiving device 50 and the load 51. The changeover switch 56 is configured to be switched between a state in which the power receiving device 50 and the load 51 are directly connected and a state in which the power receiving device 50 is connected to the load 51 through the resistor R. The resistor R is a small value resistor for detecting the current value (effective value) flowing through the load 51. The reason for this is to obtain a frequency at which the maximum power can be obtained in a state where power is supplied to the load 51. Further, by measuring the voltage across the terminals of the resistor R inserted in series with the load 51, the load current can be measured and the received power can be detected. The voltage between the terminals of the resistor R is sampled by the sampling device 52, input to the CPU 53, and data processing is performed in the CPU 53. The CPU 53 is composed of a microcomputer having a memory and an input / output interface. A transmission device 54 that transmits data is connected to the CPU 53, and a transmission antenna 55 is connected to the transmission device 54. Data obtained as a result of processing by the CPU 53 is transmitted to the receiving antenna 25 via the transmitting antenna 55 and processed by the CPU 23. The power reception device 50 is connected to a scanning start detection circuit 57, and its output is input to the CPU 53. The scanning start detection circuit 57 is configured by a filter and a rectifier circuit, and extracts the start frequency of frequency scanning by the power transmission device 1 and gives the CPU 53 the start timing of frequency scanning.

  In this embodiment, the maximum power frequency is obtained on the power receiving device 2 side, and the value is transmitted to the power transmitting device 1 as data. Next, the processing procedure of the CPU 23 of the power transmission device 1 and the processing procedure of the CPU 53 of the power receiving device 2 will be described using the flowcharts of FIGS. 2 and 3. The processing procedure of FIG. 2 is started when a main switch (not shown) for power transmission is turned on, and thereafter, a timer interrupt is repeated so as to be repeated at regular intervals until the main switch is turned off. It has been decided. In step 100, the scanning frequency for the test power is output to the power transmission frequency variable device 22 at predetermined time intervals. The scanning range and the frequency interval are determined in advance and are known values also in the power receiving device 2. The power transmission frequency variable device 22 is composed of an LC resonance circuit and is a device in which the value of the capacitance C is variable. The signal generator 21 is a circuit that generates a sine wave having a frequency determined by the resonance circuit of the power transmission frequency variable device 22. The output of the signal generator 21 is amplified by the power amplifier 20 and is output to the feeding coil 12. The power energy supplied to the feeding coil 12 is accumulated in the coupling coil 11 by magnetic coupling. That is, electrostatic magnetic electromagnetic energy is accumulated in the coupling coil 12. Further, this electromagnetic energy is also accumulated in the coupling coil 41 and the output coil 42 of the power receiving coil 40. Then, the received power is output from the output coil 42 by the power receiving device 50.

  The power receiving device 2 is configured such that when power is received in the power receiving coil 40, a main switch (not shown) is automatically turned on by the power. Then, every time there is an output from the scanning start detection circuit 57, the processing procedure of FIG. When the start frequency of the frequency scan is detected, step 200 is executed and the changeover switch 56 is switched to the power detection side. In step 202, the sampling device 52 samples the voltage across the resistor R and reads power data. This power data is continuously read until the frequency scan is completed. Next, in step 204, the frequency at which the maximum power is obtained is determined from the change characteristics of the power. In the power receiving device 2, since the frequency scanning interval is known, the time axis and the frequency can be associated with each other. This characteristic is as shown in FIG. From this characteristic, the maximum power frequency giving a peak is determined. Since two peaks are detected, the frequency with the larger peak is determined as the maximum power frequency.

  Next, in step 206, the maximum power frequency is output to the transmission device 54 as power frequency information. In the next step 208, the changeover switch 56 is switched to the load side. Then, the transmission device 54 transmits the information from the transmission antenna 55. When this information is received, the CPU 23 of the power transmission device 1 determines that data reception is Yes in step 102 in FIG. 2, and therefore, in step 104, the transmitted power frequency variable device 22 receives the received maximum power frequency. Is set. Thereby, the transmission frequency of this power becomes the maximum power frequency. Then, AC power of this frequency is supplied to the power transmission coil 10, and power is transmitted to the power reception coil 40 by electromagnetic resonance.

  As shown in FIG. 4, the transmission efficiency between the power transmission coil 10 and the power reception coil 40 is such that two frequencies giving a power peak approach as the distance between the power transmission coil 10 and the power reception coil 40 increases. Even in such a case, in the present embodiment, the frequency that gives the power peak is always detected and power is transmitted at that frequency, so regardless of the distance between the power transmitting coil 10 and the power receiving coil 40. The maximum power transmission efficiency is always achieved.

  In the present embodiment, the frequency scan is repeatedly executed at predetermined time intervals, and the frequency of the main power transmission is determined at the newly detected maximum power frequency. Therefore, the load state of the load 51 changes. Even so, the maximum power transmission efficiency can be realized regardless of the load state.

  In the above embodiment, frequency scanning is performed at predetermined time intervals, but may be executed only when the main switch of the power transmission device 1 is turned on.

  In the first embodiment, the maximum power frequency is obtained on the power receiving device 1 side. In the second embodiment, the power receiving apparatus 1 transmits the sampling value having the characteristics shown in FIG. 4 is received by the CPU 53 of the power receiving apparatus 1 on the side of the CPU 23 of the power transmitting apparatus 1, and the CPU 23 obtains the maximum power frequency. With this maximum power frequency, the frequency of the power transmission is set by the power transmission frequency variable device 22.

  In this embodiment, pulse power is transmitted instead of the frequency scanning in the first embodiment. That is, power having a spectrum in the scanning frequency range of the first embodiment is output from the power transmission device 1. In the power receiving device 2, the time characteristic of the power is input by the sampling device 52. The CPU 53 Fourier-transforms this time characteristic to obtain the frequency characteristic of FIG. 4 by calculation. And the maximum electric power frequency is calculated | required from the frequency characteristic, and the data is transmitted to the power transmission apparatus 1 side similarly to the first embodiment. Even in this way, the maximum power frequency can be determined.

  Unlike the third embodiment, instead of determining the maximum power frequency on the power receiving device 2 side, the time characteristic is transmitted as it is from the power receiving device 2 to the power transmitting device 1 as in the second embodiment. The CPU 23 of the power transmission apparatus 1 receives this time characteristic, performs Fourier transform, obtains the frequency characteristic of FIG. 4, and determines the maximum power frequency from the frequency characteristic. Even if it does in this way, the same effect as Example 1 and 3 will be achieved.

  In the third embodiment, after the time characteristics of power are input by the sampling device 52, the CPU 53 performs Fourier transform to calculate the frequency characteristics. The CPU 53 transmits this frequency characteristic to the power transmission device 1 side as in the second embodiment. Then, the CPU 23 of the power transmission device 1 determines the maximum power frequency from the received frequency characteristic. Also with this configuration, the same effect as in the first embodiment can be realized.

  In all the examples, the test power for determining the maximum power frequency may be lower than the main power or the main power. For data transmission, the power transmission coil 10 may be used instead of the power reception coil 40 and the reception antenna 10 instead of the transmission antenna 55. In all the embodiments, 10 MHz is used for power transmission, but this frequency can be in the range of 1 to 100 MHz and 5 to 50 MHz. Although it can be used even in the several hundred kHz band, the self-inductance cannot be increased. Therefore, in order to maintain high transmission efficiency even when the distance between the power transmission coil 10 and the power reception coil 40 is long, the above-mentioned MHz is used. It is better to use the frequency of the band. In addition, data transmission can be performed using signals of 300 MHz and several GHz band higher than this frequency, regardless of whether the transmitting antenna 55 and the receiving antenna 25 are used or the power receiving coil 40 and the power transmitting coil 10 are used. .

  In the embodiment, the frequency characteristic detection device in the claims is realized by the power receiving device 50, the switching device 56, the sampling device 52, the CPU 53, and steps 200 and 202 of the processing procedure of the CPU 53. In addition, the transmission device of the claims is realized by the CPU 53 and steps 204 and 206 of the processing procedure of the CPU 53 in addition to the transmission device 54 in the embodiment. The frequency scanning device according to the claims is realized by the CPU 23 and step 100 of the processing procedure of the CPU 23. The frequency control device according to the claims is implemented by the CPU 23 and step 104 of the processing procedure of the CPU 23. The broadband power output apparatus according to the claims is realized by the processing procedure of the CPU 23 in addition to the CPU 23 and the signal generator 21 that outputs pulse power.

  INDUSTRIAL APPLICABILITY The present invention can be used for a device that performs power supply to a battery such as an electric vehicle or an electronic device in a non-contact manner.

DESCRIPTION OF SYMBOLS 1 ... Power transmission apparatus 2 ... Power receiving apparatus
10 ... Power transmission coil
DESCRIPTION OF SYMBOLS 11,41 ... Coupling coil 12 ... Feeding coil 41 ... Output coil 11, 41 ... Coupling coil

Claims (11)

In a magnetic resonance power transmission method in which a power transmission coil by self-resonance and a power reception coil by self-resonance are coupled to transmit power from the power transmission coil to the power reception coil wirelessly by magnetic resonance.
A magnetic resonance power transmission method, comprising: detecting a maximum power frequency at which power received by a power receiving coil is maximized; and transmitting power by matching a frequency of power transmitted by a power transmission coil to the maximum power frequency.   The frequency of the power transmitted from the power transmission coil is sequentially changed, the power is received by the power receiving coil, the frequency characteristic of the received power is detected, and the frequency characteristic or the received power obtained from the frequency characteristic 2. The magnetic resonance power transmission method according to claim 1, wherein power frequency information including a maximum power frequency at which power is maximized is fed back to the power transmission coil side to determine the frequency of power transmitted by the power transmission coil. .   The power transmitted from the power transmission coil is transmitted as a wideband frequency including the maximum power frequency, the power is received by the power receiving coil, the time variation characteristic of the power is detected, or the frequency of the time variation characteristic The frequency characteristic by analysis is detected, and the time variation characteristic, the frequency characteristic, or the power frequency information including the maximum power frequency at which the received power obtained from the frequency characteristic is maximized is fed back to the power transmission coil side. The magnetic resonance power transmission method according to claim 1, wherein a frequency of power transmitted by the power transmission coil is determined.   4. The magnetic resonance according to claim 2, wherein the test transmission power for detecting the maximum power frequency is smaller than the main transmission power transmitted in accordance with the maximum power frequency. 5. Power transmission method.   5. The magnetic resonance according to claim 2, wherein the feedback of the power frequency information is performed by a transmission antenna and a reception antenna of different systems for the power transmission coil and the power reception coil. Power transmission method.   5. The magnetic resonance power transmission method according to claim 2, wherein the feedback of the power frequency information is performed by transmitting the information from the power reception coil to the power transmission coil. 6. . A power transmission coil by self-resonance, a power transmission device that supplies transmission power to the power transmission coil, a power reception coil by self-resonance that is electromagnetically coupled to the power transmission coil, and a power reception device that inputs power from the power reception coil and supplies power to the load In a magnetic resonance power transmission device having a device,
The power receiving device is:
A frequency characteristic detection device for detecting the frequency characteristic of the received power from the power receiving coil;
A transmission device that transmits to the power transmission device, the frequency characteristics, or power frequency information including a maximum power frequency at which received power obtained from the frequency characteristics is maximized,
The power transmission device is:
A transmission frequency variable device capable of varying the frequency of transmitted power;
A frequency scanning device that sequentially changes the frequency of the transmitted power transmitted from the power transmission coil; and
A receiving device that receives the power frequency information transmitted from the transmitting device;
When the power frequency information received by the receiving device is the frequency characteristic, the maximum power frequency at which the received power is maximized is detected, and based on the maximum power frequency, the power transmission frequency variable device When the frequency of transmitted power is matched with the maximum power frequency, and the power frequency information is the maximum power frequency, based on the maximum power frequency, the frequency of the transmitted power by the transmission frequency variable device is And a frequency control device that matches the maximum power frequency. A power transmission coil by self-resonance, a power transmission device that supplies transmission power to the power transmission coil, a power reception coil by self-resonance that is electromagnetically coupled to the power transmission coil, and a power reception device that inputs power from the power reception coil and supplies power to the load In a magnetic resonance power transmission device having a device,
The power receiving device is:
A frequency characteristic detection device that detects a time change characteristic of received power from a power receiving coil, or detects a frequency characteristic by frequency analysis of the time change characteristic;
A transmitter that transmits power frequency information including the maximum power frequency at which the received power obtained from the time change characteristic, the frequency characteristic, or the frequency characteristic is maximized, to the power transmission apparatus,
The power transmission device is:
A transmission frequency variable device capable of varying the frequency of transmitted power;
Wide-band power output device for transmitting power transmitted from the power transmission coil as a wide-band frequency including the maximum power frequency, and
A receiving device that receives the power frequency information transmitted from the transmitting device;
When the power frequency information received by the receiving device is the time change characteristic, the frequency characteristic is obtained from the time change characteristic, the maximum power frequency is detected from the frequency characteristic, and the frequency characteristic is In some cases, the maximum power frequency at which the received power is maximized is detected, the frequency of the transmission power is matched with the maximum power frequency based on the detected maximum power frequency, and the power frequency information is the maximum power frequency. And a frequency control device that matches the frequency of the transmission power by the transmission frequency variable device with the maximum power frequency based on the maximum power frequency. Transmission equipment.   9. The magnetic transmission according to claim 7, wherein the test transmission power for detecting the maximum power frequency is smaller than the main transmission power transmitted in accordance with the maximum power frequency. Resonant power transmission device. The power receiving device has a transmission antenna for transmitting the power frequency information to the power transmission device,
10. The magnetic resonance power transmission apparatus according to claim 7, wherein the power transmission apparatus includes a reception antenna that receives the power frequency information transmitted from the transmission antenna. 11.   The magnetic resonance power transmission apparatus according to claim 10, wherein the transmission antenna is the power reception coil, and the reception antenna is the power transmission coil.

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