Design of high performance magnetron power supply on the basis of pwm power control

Abstract

This paper proposed a kind of high-performance magnetron power supply circuit, the output power of which could be regulated precisely and stably. Based upon the LLC resonant converter with multiplier, efficient power conversion and stable loop control were realized when the switch frequency was near to the resonant frequency. The driving pulses of the switches were controlled by a low-frequency PWM signal, thus realizing the intermittent operation mode. Therefore, the output voltage was in the form of pulsation, which met the requirement of the magnetron. Furthermore, the mean output power of the microwave could be regulated through the PWM duty ratio. An experimental prototype of 1000 W magnetron power supply was completed. As shown in the experiment, the soft switch of this circuit possessed excellent performance. The converting efficiency was higher than 93%; moreover, its output power could be easily adjusted.