Seamless Dual Mode Control Scheme for Dual Active Bridge Converter to Achieve Full Load Range Soft Switching and Minimum Current Stress

A Seamless Dual mode control (SDMC) scheme is proposed for dual active bridge (DAB) converter to achieve full load range zero voltage switching (ZVS) of all switches and minimum transformer peak current. Two control variables are defined for respective operating modes to implement the control scheme. ZVS conditions and transformer peak current characteristics are analyzed for respective operating modes while considering the switch junction capacitance and transformer magnetizing inductance. Based on the ZVS and peak current analysis a control scheme is developed to ensure full range ZVS and minimum peak current. The proposed control scheme offers seamless transition and reduced control complexity. The ZVS range and peak current is compared with existing control methods over a wide voltage range. Finally., a prototype of 5.5 kW is built to verify the validity of theoretical analysis.