Wide ZVS Range Full-Bridge DC-DC Converter with Quasi-Resonant Switching

The article presents a control algorithm of a bidirectional isolated converter with insulated gate bipolar transistors (IGBT). The primary stage of the converter is a traditional full-bridge voltage-source inverter (Voltage-Fed, VF) based on IGBT with reverse diodes shunted by snubber capacitors. The secondary stage is based on IGBT with reverse diodes full-bridge Current-Fed (CF) inverter and a bidirectional four-quadrant power switch (FQS) based on two IGBT with reverse diodes is connected in series with the transformer. For the energy transfer mode from the VF stage to the CF stage, a separated- commutation switching algorithm that provides a zero current switching (ZCS) turn-off mode and an inductive snubber turn-on mode for the CF switches, and a zero-voltage-switching (ZVS) and capacitive snubber turn-off mode for the VF switches is described. Leakage inductance of the transformer is used as an inductive snubber. When the transistors of the VF stage are turning-off, an additional, in comparison with the known solutions, forced switching-on of the CF stage main transistors on the interval of half-period provides a resonant overcharge of the snubber capacitors. This ensures the ZVS mode of turning on of the VF stage transistors in a wide range of load current changes, up to idle mode. The proposed ideas are verified with simulations in MATLAB. The topology is proposed for high power battery energy storage systems.