Novel soft-switching full-bridge converter with magnetic amplifiers

A novel full-bridge DC-to-DC converter combines the functions of the lossless soft-switching and secondary side PWM output voltage regulation at constant-switching frequency. The primary side switches of the bridge are driven at constant frequency and near 50% duty ratios with small dead-times, while the output voltage is regulated by PWM control of the magnetic amplifiers on the secondary side. The proposed converter exhibits soft-switching for no-load to full load conditions and maintains high overall efficiency. Experimental results obtained on 300 W, 48 V prototype operated from 300 VDC confirm those features.