Three-level dual active bridge with auxiliary inductor for wide zero voltage switching for energy storage system in DC microgrid

This paper proposes a three-level bidirectional DC-DC converter with an auxiliary inductor for wide zero-voltage switching (ZVS) in high-output voltage applications. The auxiliary inductor is connected across the middle node of the split flying capacitors and the center tap of the secondary winding in the transformer. The phase-shift angle in three-level stage can facilitate the ZVS of the switches in thee-level stage. The modulation trajectory to maintain the full-operation ZVS range with low condition loss is proposed. Finally, the experimental results verify the theoretical analyses and ZVS performance across the whole power and voltage range, and the efficiency curves demonstrate the efficiency improvement.