A novel zero-current-transition full-bridge DC-DC converter

A new soft-switching full-bridge converter with IGBTs as the main switch is presented. On one hand soft-switching is used to achieve higher possible switching frequencies, and on the other hand to reduce the effect of current derating of the IGBT, i.e. the overrating of the switches is reduced. The presented DC-DC converter uses two auxiliary resonant circuits based on the zero-current-transition principle to obtain a lossless turn-off of all four main switches. The principle of operation of the converter is described and all limitations of the possible operating range introduced by the soft-switching scheme are given. The influence of parasitic elements on the placement of the auxiliary circuits and therefore on the converter topology is investigated using the network simulator SABER and physically based models for the power semiconductor devices. The theoretical results are validated by an experimental prototype with 1 kW output power and 100 kHz switching frequency.