Seamless Dual Mode Control Strategy for Wide Soft Switching Range in Consumer-Centric Dual Active Bridge Converters

The realization of Zero Voltage Switching (ZVS) for all active switches throughout the operating range is critical to achieve high efficiency and meet the power density requirements of modern isolated bidirectional single-stage DC–DC converters. This paper proposes a novel Seamless Dual Mode Control (SDMC) strategy for the Dual Active Bridge (DAB) converter, enabling the full load range ZVS of all switches while minimizing transformer peak current. Two control variables are introduced to govern the respective operating modes, facilitating optimal control across a wide output voltage range. A detailed analysis of ZVS conditions and transformer peak current behaviour are presented for each mode, explicitly considering the impact of switch junction capacitance and transformer magnetizing inductance. Based on these analytical models, a unified control scheme is developed to ensure complete ZVS, minimized peak current, and seamless mode transitions without compromising system performance. Comparative evaluations demonstrate that SDMC significantly improves conversion efficiency relative to conventional phase shift (CPS) control, extended phase shift with current stress optimization (EPS-CSO), and other state-of-the-art techniques. Experimental results obtained from a 5.5 kW laboratory prototype validate the effectiveness of the proposed SDMC method. The proposed approach offers a promising solution for enhancing the performance and reliability of high-power isolated bidirectional DC-DC converters operating under wide voltage.