Light-load efficiency improvement by extending ZVS range in DAB-bidirectional DC-DC converter for energy storage applications

This paper proposes a method to enhance the efficiency of dual active-bridge (DAB) bidirectional DC-DC converter under light-load condition for energy storage applications. Two-inductors are operated according to higher and lower phase shift regions using single-pole double-throw (SPDT) relay. In-effect the soft switching region gets extended under light load-condition using the proposed method. It also offers the advantages of reduction in peak current drawn by the high voltage (HV) and low voltage (LV) bridges and hence minimizes the conduction and switching losses. The proposed operation using SPDT relay improves the efficiency by extending the soft switching region under light-load condition. The proposed operation of the DAB converter is verified through simulation and experimental results.