Patent ID: 8872385
Filing Date: 2014-10-28
Classification: H02J,H02M,Y02B

Abstract:
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.