Comparison of bi-directional voltage-fed and current-fed dual active bridge isolated dc/dc converters low voltage high current applications

This paper presents a comparison of two potential soft-switching bi-directional high-frequency transformer isolated voltage-fed and current-fed dual active bridge dc/dc converters for fuel cell vehicle application. The comparison and discussion are conducted over the suitability of these two converters acting as a front-end dc/dc converter for a fuel cell inverter from the perspective of the circulating and peak currents, RMS currents through the devices, components´ ratings, size, losses, and efficiency. Software package PSIM 9.0.4 has been utilized to justify the merits of current-fed converter over voltage-fed converter for the given application. Experimental results of current-fed converter have also been provided. Switching losses are reduced significantly owing to zero-current switching (ZCS) of primary switches and zero-voltage switching (ZVS) of secondary switches, which allow high switching frequency operation resulting in a compact and low cost system.