WIRELESS POWER TRANSMISSION SYSTEM
First Claim
1. A wireless power transmission system that transmits power wirelessly from a power transmitter to a power receiver,wherein the power transmitter includes:
- a periodic signal generator, which generates a periodic signal;
a switch, which performs a switching operation in response to the periodic signal supplied from the periodic signal generator;
a first inductor, which connects a DC power supply to one terminal of the switch;
a first capacitor, which connects the one terminal of the switch to ground;
an LC resonant circuit, which is comprised of a second inductor and a second capacitor that are connected to the one terminal of the switch;
a transmitting-end resonant circuit, which is connected to the LC resonant circuit and of which the resonant frequency substantially corresponds with one period of the periodic signal;
a detector, which detects a voltage at the one terminal of the switch or current or a voltage at the other terminal of the switch; and
a signal extractor, which extracts a signal from the output of the detector,the power transmitter performing a class E amplification operation that converts power supplied from the DC power supply into an AC signal that has substantially the same frequency as the periodic signal by turning the switch using the periodic signal, andwherein the power receiver includes;
a receiving-end resonant circuit, which is coupled electromagnetically to, and produces resonance with, the transmitting-end resonant circuit;
a rectifier circuit, which rectifies a signal that has been received at the receiving-end resonant circuit;
an impedance changer, which connects the rectifier circuit to a power reproducing section;
the power reproducing section, which reproduces power for the power receiver based on the output of the impedance changer; and
a controller, which changes the impedance of the impedance changer according to the signal to be transmitted from the power receiver to the power transmitter.
1 Assignment
0 Petitions
Accused Products
Abstract
A wireless power transmission system transmits power wirelessly from a power transmitter to a power receiver. The power transmitter includes a class E amplifier, a transmitting-end resonant circuit, a detector that detects a voltage or current waveform at a predetermined position in the class E amplifier in accordance with the impedance of the transmitting-end resonant circuit as viewed from the class E amplifier, and a signal extractor that extracts a signal according to the waveform. The power receiver includes a receiving-end resonant circuit, a rectifier circuit, a power reproducing section, and an impedance changer connected between the rectifier circuit and the power reproducing section to change its impedance. When the impedance is changed, the detector detects the waveform variation and the signal extractor extracts and outputs a signal corresponding to the waveform detected by the detector.
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Citations
22 Claims
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1. A wireless power transmission system that transmits power wirelessly from a power transmitter to a power receiver,
wherein the power transmitter includes: -
a periodic signal generator, which generates a periodic signal; a switch, which performs a switching operation in response to the periodic signal supplied from the periodic signal generator; a first inductor, which connects a DC power supply to one terminal of the switch; a first capacitor, which connects the one terminal of the switch to ground; an LC resonant circuit, which is comprised of a second inductor and a second capacitor that are connected to the one terminal of the switch; a transmitting-end resonant circuit, which is connected to the LC resonant circuit and of which the resonant frequency substantially corresponds with one period of the periodic signal; a detector, which detects a voltage at the one terminal of the switch or current or a voltage at the other terminal of the switch; and a signal extractor, which extracts a signal from the output of the detector, the power transmitter performing a class E amplification operation that converts power supplied from the DC power supply into an AC signal that has substantially the same frequency as the periodic signal by turning the switch using the periodic signal, and wherein the power receiver includes; a receiving-end resonant circuit, which is coupled electromagnetically to, and produces resonance with, the transmitting-end resonant circuit; a rectifier circuit, which rectifies a signal that has been received at the receiving-end resonant circuit; an impedance changer, which connects the rectifier circuit to a power reproducing section; the power reproducing section, which reproduces power for the power receiver based on the output of the impedance changer; and a controller, which changes the impedance of the impedance changer according to the signal to be transmitted from the power receiver to the power transmitter. - View Dependent Claims (2, 3, 4, 5)
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6. A wireless power transmission system that transmits power wirelessly from a power transmitter to a power receiver,
wherein the power transmitter includes: -
a periodic signal generator, which generates a periodic signal; a switch, which performs a switching operation in response to the periodic signal supplied from the periodic signal generator; a first inductor, which connects a DC power supply to one terminal of the switch; a first capacitor, which connects the one terminal of the switch to ground; an LC resonant circuit, which is comprised of a second inductor and a second capacitor that are connected to the one terminal of the switch; a transmitting-end resonant circuit, which is connected to the LC resonant circuit and of which the resonant frequency substantially corresponds with one period of the periodic signal; a detector, which detects a voltage at the one terminal of the switch or current or a voltage at the other terminal of the switch; a signal extractor, which extracts a signal from the output of the detector; and a voltage controller, which controls the output voltage of the DC power supply in accordance with a first transmission signal to be transmitted from the power transmitter to the power receiver, the power transmitter performing a class E amplification operation that converts power supplied from the DC power supply into an AC signal that has substantially the same frequency as the periodic signal by turning the switch using the periodic signal, and wherein the power receiver includes; a receiving-end resonant circuit, which is coupled electromagnetically to, and produces resonance with, the transmitting-end resonant circuit; a rectifier circuit, which rectifies a signal that has been received at the receiving-end resonant circuit; an impedance changer, which connects the rectifier circuit to a power reproducing section; the power reproducing section, which reproduces power for the power receiver based on the output of the impedance changer; a demodulator, which demodulates the first transmission signal based on the output of the impedance changer; and a controller, which changes the impedance of the impedance changer according to a second transmission signal to be transmitted from the power receiver to the power transmitter. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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13. A wireless power transmission system that transmits power wirelessly from a power transmitter to a power receiver,
wherein the power transmitter includes: -
a periodic signal generator, which generates a periodic signal; a pulse width modulation signal generator, which generates a pulse width modulation signal in accordance with a first transmission signal to be transmitted from the power transmitter to the power receiver; a modulator, which modulates the periodic signal with the pulse width modulation signal; a switch, which performs a switching operation in accordance with the output of the modulator; a first inductor, which connects a DC power supply to one terminal of the switch; a first capacitor, which connects the one terminal of the switch to ground; an LC resonant circuit, which is comprised of a second inductor and a second capacitor that are connected to the one terminal of the switch; a transmitting-end resonant circuit, which is connected to the LC resonant circuit and of which the resonant frequency substantially corresponds with one period of the periodic signal; a detector, which detects a voltage at the one terminal of the switch or current or a voltage at the other terminal of the switch; and a signal extractor, which extracts a signal from the output of the detector, wherein the power receiver includes; a receiving-end resonant circuit, which is coupled electromagnetically to, and produces resonance with, the transmitting-end resonant circuit; a rectifier circuit, which rectifies a signal that has been received at the receiving-end resonant circuit; an impedance changer, which connects the rectifier circuit to a power reproducing section; the power reproducing section, which reproduces power for the power receiver based on the output of the impedance changer; an envelope detector, which detects the envelope of the output of the impedance changer; a pulse width modulation signal demodulator, which demodulates the first transmission signal based on the output of the envelope detector; and a controller, which changes the impedance of the impedance changer according to second transmission signal to be transmitted from the power receiver to the power transmitter. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. A wireless power transmission system that transmits power wirelessly from a power transmitter to a power receiver,
wherein the power transmitter includes: -
a class E amplifier, which produces AC energy; a transmitting-end resonant circuit, which transmits the AC energy into space; a detector, which detects a voltage or current waveform at a predetermined position in the class E amplifier in accordance with the impedance of the transmitting-end resonant circuit as viewed from the class E amplifier; and a signal extractor, which extracts a signal according to the waveform, and wherein the power receiver includes; a receiving-end resonant circuit, which receives at least a part of the AC energy that has been transmitted by the transmitting-end resonant circuit; a rectifier circuit, which rectifies and outputs at least the part of the AC energy that has been received at the receiving-end resonant circuit; a power reproducing section, which outputs power based on the output of the rectifier circuit; and an impedance changer, which is connected between the rectifier circuit and the power reproducing section to change the impedance, and wherein as the impedance changer changes the impedance, the detector detects a waveform when the impedances match and a waveform when the impedance do not match and the signal extractor extracts and outputs a signal associated with the waveform that has been detected by the detector. - View Dependent Claims (21, 22)
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Specification