Pulse width and pulse frequency modulation pattern controlled ZVS inverter type AC-DC power converter with lowered utility AC grid side harmonic current components for magnetron drive

The grid voltage of commercial utility power source in Japan and USA is 100 V, but in China and European countries, it is 200 V. In recent years, in Japan, 200 V output single-phase three-wire power systems have begun to be used for high power applications. In 100 V utility AC power applications and systems, an active voltage clamped quasi-resonant inverter circuit topology using IGBTs has been effectively used so far for the consumer microwave oven. In this paper, the authors present a half bridge type voltage-clamped high-frequency inverter type AC-DC power converter using which is designed for consumer magnetron drives used in consumer microwave ovens on 200 V utility AC power systems. This zero voltage soft switching inverter can use the same power rated switching semiconductor devices and three-winding high frequency transformer as those of the active voltage clamped quasi-resonant inverter using the IGBTs that has already been used for 100 V utility AC power sources. The operating performances of the voltage source single ended push pull type inverter are evaluated and discussed for a consumer microwave oven. The harmonic line current components in the utility AC power side of the AC-DC power converter operating at ZVS-PWM strategy were reduced and improved upon the basis of sine wave like pulse frequency modulation and sine wave like pulse width modulation for the utility AC voltage source.