POWER TRANSMISSION SYSTEM

摘要

A power transmission system (1) transmits power from a power transmission device (101) to a power reception device (201) by electric coupling. In the power transmission system (1), the power transmission device (101) comprises: a step-up transformer (T1) for stepping up the AC voltage output from an inverter circuit (12) and applying to an active electrode (13) and a passive electrode (14); and a parallel resonant circuit configured by including part of the step-up transformer. The power reception device (201) comprises: a piezoelectric transformer (22) for stepping down the voltage induced on an active electrode (23) and a passive electrode (24); and a series resonant circuit including the piezoelectric transformer (22) and having the same resonant frequency as the parallel resonant circuit. The power transmission device (101) sweeps driving frequency to detect the resonant frequency of the parallel resonant circuit and the series resonant circuit and sets the detected resonant frequency as the driving frequency at a predetermined cycle to PWM control the inverter circuit (12). This provides a power transmission system for transmitting power while avoiding the reduction of transmission efficiency.