A Novel ZVS Range Enhancement Technique of a High-Voltage Dual Active Bridge Converter Using Series Injection

In this paper, a novel technique is proposed to extend the region of zero voltage switching (ZVS) of a dual active bridge (DAB) dc–dc converter using an auxiliary series injection transformer. The series voltage injection by the series transformer helps us to maintain ZVS by controlling the reactive power flow through the main converter of the DAB. A model for the series compensation is developed to compute the phase angle of the series voltage to obtain the optimum efficiency over the entire region of operation. The proposed technique is validated through simulations and the corresponding converter loss reduction is presented. The system is implemented on a high-voltage hardware with $6$ kV- $270$ V DAB using 10-kV SiC mosfet -based converter in the primary and 1200-V SiC mosfet on the secondary side of the transformer and the corresponding results are presented.