JP2012023548A - Electric power transmission/reception system, electric power transmission device, electric power reception device, and electric power transmission/reception method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a signal synchronized between two devices accurately without using a carrier wave as a reference wave.SOLUTION: An electric power transmission/reception system includes a first device and a second device. The first device includes: an electric power source that supplies electric power; an electric power wireless transmission unit for generating a high-frequency electric power having a predetermined phase and frequency using the electric power supplied from the electric power source and wirelessly transmitting the high-frequency electric power by a resonance system; and a first reference signal generating unit for generating a reference signal whose phase and frequency are the same as those of the high-frequency electric power. The second device includes: a electric power wireless reception unit for receiving the high-frequency electric power from the electric power wireless transmission unit by a resonance system and supplying electric power to the second device; and a second reference signal generating unit for generating a reference signal whose phase and frequency are the same as those of the high-frequency electric power received by the electric power wireless reception unit.

Description

  The present invention relates to a technique for generating a reference signal synchronized between one device and another device.

  In recent wireless communication apparatuses, a synchronous detection method is often adopted. The synchronous detection method is a technique for demodulating a received signal with high accuracy (see Non-Patent Document 1). FIG. 6 is a diagram illustrating an outline of a wireless communication system employing a synchronous detection method (particularly, a carrier wave recovery method). In FIG. 6, two wireless devices P10 having the same configuration mutually transmit and receive signals by wireless transmission. The wireless device P10 includes a reference signal source P102. The reference signal source P102 of each wireless device P10 is synchronized within a predetermined accuracy range. The wireless devices P10 perform synchronous detection based on the reference signal output from the reference signal source P102. Specifically, it is as follows. The transmitting-side radio apparatus P10 generates a carrier wave by performing modulation based on the reference signal output from the reference signal source P102. The transmitting-side radio apparatus P10 transmits a carrier wave. The receiving-side radio apparatus P10 includes a reference signal source P102, a carrier recovery unit P304, a clock recovery unit P306, and the like for performing synchronous detection. The receiving-side radio apparatus P10 demodulates and decodes the received carrier wave based on the reference signal output from the reference signal source P102.

  Further, not only a system that wirelessly transmits signals as described above, but also a system that wirelessly transmits power (see Non-Patent Document 2). In a power wireless transmission system, an antenna configured by a loop coil or the like is provided in a power transmission device and a power reception device. Then, power is wirelessly transmitted using a resonance (resonance) phenomenon between the antennas.

Kimio Tanaka, “Digital Communication Technology”, Tokai University Press, March 25, 1986 Andre Kurs, et al., "Wireless Power Transfer via Strongly Coupled Magnetic Resonances", Science 317, 83 (2007)

In a wireless communication system employing the above-described synchronous detection method, a carrier wave wirelessly transmitted from the transmitting-side wireless device P10 to the receiving-side wireless device P10 is used as a reference signal. That is, the receiving-side radio apparatus P10 synchronizes the reference signal output from the reference signal source P102 with a carrier wave. Then, the radio device P10 on the receiving side performs synchronous detection using the reference signal synchronized with the carrier wave. Therefore, the carrier wave needs to be wirelessly transmitted with low noise. That is, when the carrier wave is not transmitted wirelessly with low noise, there is a problem that the accuracy of synchronous detection is lowered.
In view of the above circumstances, an object of the present invention is to provide a technique capable of generating a signal that is accurately synchronized between one device and the other device without using a carrier wave as a reference wave. Yes.

  One aspect of the present invention is a power transmission / reception system including a first device and a second device, wherein the first device uses a power source that supplies power and power that is supplied from the power source. A power wireless transmission unit that generates high-frequency power of phase and frequency and wirelessly transmits the high-frequency power by a resonance method; and a first reference signal generation unit that generates a reference signal of the same phase and frequency as the high-frequency power. The second device receives a high frequency power from the power wireless transmission unit by a resonance method and supplies power to the second device; and the high frequency power received by the power wireless transmission unit And a second reference signal generation unit that generates a reference signal having the same phase and frequency.

  One aspect of the present invention is the above power transmission / reception system, wherein the first device generates and transmits a transmission target information based on the reference signal generated by the first reference signal generation unit. A receiving unit that receives the carrier wave transmitted from the transmitting unit and detects the carrier wave based on the reference signal generated by the second reference signal generating unit. Is further provided.

  One aspect of the present invention is a power transmission that transmits power to a power reception device that receives high-frequency power by a resonance method, supplies power to the device itself, and generates a reference signal having the same phase and frequency as the high-frequency power. A power source that supplies power, and a power wireless transmission unit that generates high-frequency power having a predetermined phase and frequency using the power supplied from the power source and wirelessly transmits the high-frequency power using a resonance method And a first reference signal generator that generates a reference signal having the same phase and frequency as the high-frequency power.

  One aspect of the present invention is a power receiving apparatus that generates high-frequency power having a predetermined phase and frequency using power supplied from a power source, wirelessly transmits the high-frequency power using a resonance method, and the high-frequency power. A power wireless reception unit that receives high-frequency power by a resonance method from a power transmission device that generates a reference signal having the same phase and frequency, and supplies power to the second device; and the high-frequency power received by the power wireless transmission unit And a second reference signal generation unit that generates a reference signal having the same phase and frequency as the power.

  One aspect of the present invention is a power transmission / reception method performed by a power transmission / reception system including a first device having a power supply for supplying power and a second device, wherein the first device supplies power supplied from the power supply. A power wireless transmission step of generating high-frequency power having a predetermined phase and frequency and wirelessly transmitting the high-frequency power by a resonance method; and the first device uses a reference signal having the same phase and frequency as the high-frequency power. A first reference signal generation step to generate; a power wireless reception step in which the second device receives high-frequency power by a resonance method and supplies power to the second device; and the second device transmits the power wireless transmission And a second reference signal generation step of generating a reference signal having the same phase and frequency as the high-frequency power received by the step.

  According to the present invention, it is possible to generate a signal that is accurately synchronized between one device and the other device without using a carrier wave as a reference wave.

It is a system configuration figure showing the system configuration of a radio transmission system. It is a figure showing the function structure of a 1st radio | wireless apparatus. It is a figure showing the function structure of a 2nd radio | wireless apparatus. It is a sequence diagram showing the flow of operation | movement of the power transmission in a wireless transmission system. It is a sequence diagram showing the flow of operation | movement of the information wireless transmission in a wireless transmission system. It is a figure showing the outline of the radio | wireless communications system which employ | adopted the synchronous detection system.

  FIG. 1 is a system configuration diagram illustrating a system configuration of the wireless transmission system 100. The wireless transmission system 100 includes a plurality of wireless devices. Part of the wireless device included in the wireless transmission system 100 is the first wireless device 10 on the power transmission side. Another part of the wireless device included in the wireless transmission system 100 is a second wireless device 50 on the power receiving side. The first wireless device 10 includes a power supply, and transmits a part of the power output from the power supply to the second wireless device 50 wirelessly. The second radio apparatus 50 receives power wirelessly transmitted from the first radio apparatus 10 and operates with this power. The first radio apparatus 10 and the second radio apparatus 50 perform synchronous detection based on the frequency and phase used for wireless transmission of power. Hereinafter, the first radio apparatus 10 and the second radio apparatus 50 will be described in detail. In FIG. 1, a configuration in which the wireless transmission system 100 includes one first wireless device 10 and one second wireless device 50 is illustrated, but the number of devices is not limited to one.

  FIG. 2 is a diagram illustrating a functional configuration of the first radio apparatus 10. The first wireless device 10 includes a CPU (Central Processing Unit), a memory, an auxiliary storage device, and the like connected by a bus, and executes a first communication program. The first radio apparatus 10 includes a power transmission unit 20, a transmission unit 30, and a reception unit 40. All or some of the functions of the first wireless device 10 may be realized using an application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA), or other hardware. .

  The power transmission unit 20 wirelessly transmits power to the second wireless device 50 by the magnetic field resonance method. The transmission unit 30 performs modulation based on the reference signal output from the power transmission unit 20. Then, the transmission unit 30 wirelessly transmits the modulated signal to the second wireless device 50. The receiving unit 40 receives a signal from the second wireless device 50 wirelessly. Then, the receiving unit 40 performs synchronous detection based on the reference signal output from the power transmission unit 20.

  The power transmission unit 20 includes a power source 201, a power wireless transmission unit 202, and a power transmission coil 203. The power source 201 supplies power to the power wireless transmission unit 202, the transmission unit 30, and the reception unit 40. The power wireless transmission unit 202 generates high-frequency power having a predetermined cycle and phase, and wirelessly transmits the power via the power transmission coil 203. At this time, in order to increase the efficiency of power transmission, power transmission is performed at an extremely narrow band frequency, and the Q value becomes several thousand or more. The high frequency power generated by the power wireless transmission unit 202 is, for example, power having a frequency of several MHz to several tens of MHz. Further, the power wireless transmission unit 202 outputs a reference signal having the same phase and frequency as the generated high-frequency power to the transmission unit 30 and the reception unit 40. The frequency of the reference signal may be a frequency obtained by multiplying the frequency of the generated high-frequency power. The output destination of the reference signal is, for example, the modulation unit 303, the radio unit 304, the radio unit 304, the demodulation unit 403, and the decoding unit 404. In addition, the frequency of the high frequency electric power which the electric power wireless transmission part 202 produces | generates is not limited to said frequency. The power transmission coil 203 has a resonance frequency that is equal to or almost equal to that of the power reception coil provided in the second radio apparatus 50. The power transmission coil 203 forms an electromagnetic field by receiving power supply from the power wireless transmission unit 202.

  The transmission unit 30 includes a digital signal processing unit 301, an encoding unit 302, a modulation unit 303, a radio unit 304, and a transmission antenna 305. The digital signal processing unit 301 generates a bit string to be transmitted to another wireless device by performing digital signal processing. The encoding unit 302 generates encoded data by performing an encoding process on the bit string generated by the digital signal processing unit 301. Examples of the encoding process performed by the encoding unit 302 include error correction encoding and convolutional encoding. Modulation section 303 performs modulation processing on the encoded data based on the reference signal output from power wireless transmission section 202 to generate a modulated signal. Radio section 304 performs transmission processing such as up-conversion on the modulated signal to generate a carrier wave. The transmission antenna 305 transmits the carrier wave generated by the wireless unit 304 to the second wireless device 50.

  The reception unit 40 includes a reception antenna 401, a radio unit 402, a demodulation unit 403, a decoding unit 404, and a digital signal processing unit 405. The receiving antenna 401 receives a carrier wave from the first radio apparatus 10. The radio unit 402 performs reception processing such as down-conversion on the carrier wave received by the receiving antenna 401 and restores the modulated signal. Demodulation section 403 performs demodulation processing on the modulated signal based on the reference signal output from power wireless transmission section 202 to restore the encoded data. The decoding unit 404 decodes the encoded data based on the reference signal output from the power wireless transmission unit 202 and restores the bit string. The digital signal processing unit 405 performs processing according to the restored bit string.

  FIG. 3 is a diagram illustrating a functional configuration of the second radio apparatus 50. The second wireless device 50 includes a power reception unit 60, a transmission unit 70, and a reception unit 80. The power receiving unit 60 receives power wirelessly transmitted from the first wireless device 10 by the magnetic field resonance method. The power receiving unit 60 supplies the received power to the transmitting unit 70 and the receiving unit 80. In addition, the power receiving unit 60 outputs a reference signal corresponding to the frequency and phase of the received power to the transmitting unit 70 and the receiving unit 80. The transmission unit 70 performs modulation based on the reference signal output from the power reception unit 60. Then, the transmission unit 70 wirelessly transmits the modulated signal to the second wireless device 50. The receiving unit 80 wirelessly receives a signal from the first wireless device 10. The receiving unit 80 performs synchronous detection based on the reference signal output from the power receiving unit 60.

  The power receiving unit 60 includes a power receiving coil 601 and a power wireless receiving unit 602. The power reception coil 601 resonates with the electromagnetic field generated by the power transmission coil 203 of the first radio apparatus 10 and receives the high frequency power transmitted from the power transmission coil 203. The power wireless reception unit 602 supplies the power received by the power reception coil 601 to the transmission unit 70 and the reception unit 80. Further, the power wireless reception unit 602 outputs a reference signal having the same phase and frequency as the high-frequency power received from the first wireless device 10 to the transmission unit 70 and the reception unit 80. The frequency of the reference signal may be a frequency obtained by multiplying the frequency of the received high frequency power. The output destination of the reference signal is, for example, the modulation unit 703, the radio unit 704, the radio unit 802, the demodulation unit 803, and the decoding unit 804. The power receiving coil 601 has a resonance frequency equal to or almost equal to that of the power transmitting coil provided in the first radio apparatus 10.

  The transmission unit 70 includes a digital signal processing unit 701, an encoding unit 702, a modulation unit 703, a radio unit 704, and a transmission antenna 705. The transmission unit 70 has the same configuration as the transmission unit 20 of the first radio equipment 10 except that the power and reference signal supply source is the power reception unit 60.

  The reception unit 80 includes a reception antenna 801, a radio unit 802, a demodulation unit 803, a decoding unit 804, and a digital signal processing unit 805. The receiving unit 80 has the same configuration as the receiving unit 30 of the first radio equipment 10 except that the power and reference signal is supplied from the power receiving unit 60.

  FIG. 4 is a sequence diagram illustrating a flow of power transmission operation in the wireless transmission system 100. The power wireless transmission unit 202 of the first wireless device 10 uses the power supplied from the power supply 201 to generate high-frequency power with a predetermined frequency (step S101). The power wireless transmission unit 202 supplies the generated high-frequency power to the power transmission coil 203. The power transmission coil 203 transmits electric power by forming an electromagnetic field based on the supplied high frequency power (step S102). The power receiving coil 601 of the second wireless device 20 resonates according to the electromagnetic field formed by the power transmitting coil 203, whereby high frequency power is supplied to the power wireless receiving unit 602 (step S103). The power wireless reception unit 602 supplies power to the transmission unit 70 and the reception unit 80 of the own device according to the high frequency power supplied from the first wireless device 10. Further, the power wireless reception unit 602 generates a reference signal having the same frequency and phase as the high-frequency power supplied from the first wireless device 10 (step S104). The power wireless reception unit 602 supplies the generated reference signal to the modulation unit 703, the wireless unit 704, the wireless unit 802, the demodulation unit 803, and the decoding unit 804 (step S105).

  FIG. 5 is a sequence diagram showing a flow of operation of information wireless transmission in the wireless transmission system 100. FIG. 5 shows an operation flow when information is transmitted from the first radio apparatus 10 to the second radio apparatus 50. First, the encoding unit 302 of the first radio apparatus 10 performs an encoding process on the transmission target bit string to generate encoded data (step S201). Next, the modulation unit 303 of the first radio apparatus 10 performs modulation processing based on the reference signal output from the power radio transmission unit 202, and generates a modulation signal (step S202). The radio unit 304 generates a carrier wave by transmission processing such as up-conversion for the modulated signal and transmits it from the transmission antenna 305 (step S203).

  The radio unit 802 of the second radio apparatus 50 receives a carrier wave from the first radio apparatus 10 via the reception antenna 801. The radio unit 802 performs reception processing such as down-conversion on the carrier wave received by the reception antenna 801 and restores the modulated signal. Demodulation section 803 performs demodulation processing on the modulated signal based on the reference signal output from power wireless reception section 602, and restores the encoded data (step S204). The decoding unit 804 decodes the encoded data based on the reference signal output from the power wireless transmission unit 602, and restores the bit string (step S205).

  In the wireless transmission system 100 configured as described above, a reference signal having the same phase and frequency as the high-frequency power supplied from the first wireless device 10 to the second wireless device 50 is generated in the second wireless device 50. Therefore, when generating a reference signal whose phase and frequency are synchronized between the first radio apparatus 10 and the second radio apparatus 50, it is not necessary to use a carrier wave as a reference wave. Further, it is not necessary to provide both the first radio apparatus 10 and the second radio apparatus 50 with a reference signal source that generates a reference signal whose phase and frequency are synchronized. Furthermore, since the transmission of the high frequency power is performed at a very narrow frequency, the frequency and phase are transmitted as they are with high accuracy. Therefore, in the second radio apparatus 50, functions such as the carrier recovery unit P304 and the clock recovery unit P306 that synchronize the frequency and phase of the reference signal become unnecessary.

  Further, in the wireless power transmission performed between the power transmission unit 20 and the power reception unit 60, a magnetic resonance method is used. Therefore, the frequency and phase of the high frequency power output from the power transmission unit 20 are transmitted to the power reception unit 60 with high accuracy. Therefore, the reference signal having the same phase and the same frequency can be generated with high accuracy between the first radio apparatus 10 and the second radio apparatus 50. Therefore, synchronous detection can be realized with high accuracy.

  Further, the second radio apparatus 50 receives supply of power for driving from the first radio apparatus 10. Therefore, the second wireless device 50 does not need to include a battery. Therefore, it is possible to reduce the size of the second radio apparatus 50 and reduce the manufacturing cost. In addition, by supplying power from the first wireless device 10 when necessary, it is possible to operate the second wireless device 50 without limitation on the operation time.

<Modification>
The second radio apparatus 50 may be configured to include a power source. In this case, the second radio apparatus 50 may operate using electric power supplied from a power source included in the second radio apparatus 50 and electric power wirelessly transmitted from the first radio apparatus 10.

  The power transmission unit 20 of the first radio apparatus 10 may be configured to perform impedance matching with the power reception unit 60 of the second radio apparatus 50. That is, the power transmission unit 20 may be configured to dynamically cancel the change in the mutual reactance with the power reception coil 601 by adjusting the inductance and capacitance of the power transmission coil 203.

  In the above description, the first wireless device 10 communicates with the second wireless device 50. However, the communication partner of the first wireless device 10 is not limited to the second wireless device 50 and may communicate with another first wireless device 10. Similarly, the communication partner of the second radio apparatus 50 is not limited to the first radio apparatus 10 and may communicate with another second radio apparatus 50.

  In the above description, the first wireless device 10 and the second wireless device 50 communicate wirelessly. However, the communication method is not limited to wireless, and wired communication may be performed. In the above description, the first radio apparatus 10 and the second radio apparatus 50 communicate with each other using a synchronous detection method. However, any other communication method may be adopted as long as communication is performed using a reference signal whose frequency and phase are synchronized between the first wireless device 10 and the second wireless device 50.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... 1st radio | wireless apparatus (1st apparatus, power transmission device), 20 ... Power transmission part, 30 ... Transmission part, 40 ... Reception part, 50 ... 2nd radio | wireless apparatus (2nd apparatus, power reception device), 60 ... Power receiving unit, 70 ... transmitting unit, 80 ... receiving unit, 201 ... power source, 202 ... power wireless transmitting unit (power wireless transmitting unit, first reference signal generating unit), 203 ... power transmission coil, 301 ... digital signal processing unit, 302: Encoding unit, 303: Modulation unit, 304 ... Radio unit, 305 ... Transmission antenna, 401 ... Reception antenna, 402 ... Radio unit, 403 ... Demodulation unit, 404 ... Encoding unit, 405 ... Digital signal processing unit, 601 ... Receiving coil, 602 wireless power receiver (power wireless receiver, second reference signal generator), 701 ... digital signal processor, 702 ... encoder, 703 ... modulator, 704 ... none Line unit, 705 ... Transmitting antenna, 801 ... Receiving antenna, 802 ... Radio unit, 803 ... Demodulating unit, 804 ... Coding unit, 805 ... Digital signal processing unit

Claims (5)

A power transmission / reception system comprising a first device and a second device,
The first device is:
A power supply for supplying power;
A power wireless transmission unit that generates high-frequency power having a predetermined phase and frequency using power supplied from the power source, and wirelessly transmits the high-frequency power by a resonance method;
A first reference signal generation unit that generates a reference signal having the same phase and frequency as the high-frequency power;
With
The second device is
A radio power receiver that receives high frequency power from the power radio transmitter by a resonance method and supplies power to the second device;
A second reference signal generation unit that generates a reference signal having the same phase and frequency as the high-frequency power received by the power wireless transmission unit;
A power transmission / reception system comprising: The first device further includes a transmission unit that generates and transmits a transmission target information based on the reference signal generated by the first reference signal generation unit,
The second apparatus further includes a receiving unit that receives the carrier wave transmitted from the transmitting unit and detects the carrier wave based on the reference signal generated by the second reference signal generating unit. Power transmission / reception system. A power transmission device that transmits power to a power reception device that receives high frequency power by a resonance method, supplies power to the device itself, and generates a reference signal having the same phase and frequency as the high frequency power,
A power supply for supplying power;
A power wireless transmission unit that generates high-frequency power having a predetermined phase and frequency using power supplied from the power source, and wirelessly transmits the high-frequency power by a resonance method;
A first reference signal generation unit that generates a reference signal having the same phase and frequency as the high-frequency power;
A power transmission device comprising: From a power transmission device that generates high-frequency power having a predetermined phase and frequency using power supplied from a power source, wirelessly transmits the high-frequency power by a resonance method, and generates a reference signal having the same phase and frequency as the high-frequency power A radio power receiver for receiving high frequency power by a resonance method and supplying power to the second device;
A second reference signal generation unit that generates a reference signal having the same phase and frequency as the high-frequency power received by the power wireless transmission unit;
A power receiving apparatus comprising: A power transmission / reception method performed by a power transmission / reception system including a first device and a second device having a power supply for supplying power,
The first device generates high-frequency power having a predetermined phase and frequency using power supplied from the power source, and wirelessly transmits the high-frequency power by a resonance method.
A first reference signal generating step in which the first device generates a reference signal having the same phase and frequency as the high-frequency power;
The second device receives a high frequency power by a resonance method, and a power wireless reception step of supplying power to the second device;
A second reference signal generation step in which the second device generates a reference signal having the same phase and frequency as the high-frequency power received by the power wireless transmission step;
A power transmission / reception method comprising:

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