A zero voltage switching range optimization strategy for NPC Dual-Active-Bridge Converter

Abstract

DC microgrids get a lot of attention because of its good characteristics. DC-DC converter is necessary in DC microgrids to interface energy. The dual active bridge (DAB) converter is one of most promising DC-DC converters. But when the normalized voltage gain is far from 1, the DAB converter is difficult to realize soft switching. In this paper, the neutral point clamped (NPC) dual-active-bridge (DAB) converter with a blocking capacitor is adopted. This converter is able to work in different modes to achieve wide zero voltage switching (ZVS) range. A ZVS range optimization strategy is proposed based on ZVS range analysis in different modes. This strategy makes the NPC DAB converter work in the optimal mode. The simulation results show this strategy is effective.