Efficiency optimisation of ZVS isolated bidirectional DAB converters

This study presents a control method for isolated bidirectional dual-active-bridge converters to optimise the efficiency by achieving the zero-voltage switching (ZVS) in high-voltage applications, which the switching losses are the major issues. At light-load condition, the duty control algorithm is proposed to achieve the ZVS for all switches while the triple phase shift with ZVS condition is realised at heavy load condition. The operating principles and the design considerations of the proposed control scheme are analysed in detail. A 2kW prototype converter is built up and tested to verify the feasibility of the proposed control strategy.