Multi-resonant soft-switching PWM DC-DC high-power converter with quasi resonant-poles and resonant AC tank using interal parasitic circuit components of high-voltage transformers and cable

This paper deals with a fixed frequency phased-shifted PWM multi-resonant (MR) inverter type DC-DC high-power converter with a two HFHV transformers-coupled stage, which operates under ZVS transition principles in spite of a wide PWM-based voltage regulation processing and largely-changed load conditions. This MR converter topology is composed of a series capacitor-connected parallel resonant tank which makes the most of parasitic circuit components of the two HV transformers, and two additional quasi-resonant pole circuits incorporated into the bridge. The soft switching operation and practical efficacy of this new converter circuit using the latest IGBTs are actually ascertained through a 50 kW-120 kV trial-produced converter system operating using 20 kHz/30 kHz HV transformers