INVERTER POWER SOURCE CONTROL FOR HIGH-FREQUENCY HEATER

摘要

An oscillation control signal generated in an inverter power source control circuit (12) includes: a reference voltage setting signal for approximating the current waveform of the AC output of the AC power source (1) to a sinusoidal wave by making the both sides of the waveform generate current according to the fluctuation of the PWM control signal; and a waveform shapi ng signal consisting of a peak portion adjustment signal of the sinusoidal waveform for approximating the waveform peak portion of the current waveform to a sinusoidal wave by subtraction. Accordingly, even if the PWM control signal fluctuates, it is possible to automatically improve the power factor of the power source circuit above a predetermined value by approximating the current waveform of the AC output of the AC power source to a sinusoidal wav e, thereby improving the power source efficiency.