A novel soft-switching full-bridge converter

Inserting an auxiliary switch to the conventional hard-switch full-bridge topology, a novel soft-switching full-bridge converter is proposed. Instead of the main switches, the auxiliary switch is pulse-width modulated to regulate the output voltage and soft-switching operation of the main switches can be easily achieved over full line and load ranges. Consequently, the reduced switching losses can be compensated for the auxiliary switch´s losses and its efficiency approximates to that of the phase-shift full-bridge converter. It makes the proposed converter to be an alternative approach for high frequency high efficiency power conversion applications. In addition to the circuit analysis and operation principle, a 100 kHz, 300-400 V input and a 12 V, 300 W output prototype is implemented to demonstrate its feasibility.