Duplex two switch forward transformers linked soft-switching high frequency PWM DC-DC converter with tapped inductor filters

This paper presents a novel circuit topology of a duplex two-switch forward transformer type zero-voltage and zero-current soft switching (ZVZCS) high frequency DC-DC power converter with PWM control scheme. Based on the conventional paralleled two-switch forward transformer link hard switching converter this circuit configuration does not include complex auxiliary resonant circuit except for an output side tapped-inductor smoothing filter. This new DC-DC converter has advantages as wide soft-switching operation range under broad load variations and PWM regulations, lowered level of the idle and circulating currents through circuit components, small ripple output voltage. The basic operating principle of the converter is illustrated by equivalent circuit for each mode with detailed explanation. Moreover, the feasible practical effectiveness of the proposed soft-switching DC-DC power converter realized on the 500 W 100 kHz breadboard setup is verified and evaluated on basis of simulation and experimental results.