Comparative Analysis of Single Phase Shift Control and Optimized Extended Phase Shift Control of Dual Active Bridge Converters for Wide Voltage Range Applications

The dual active bridge (DAB) converter is a popular candidate for DC-DC converter applications in industrial and automotive applications. While single phase shift (SPS) control is the conventional control technique for DAB converters, different phase shift control techniques have been proposed with multiple control variables. Extended phase shift (EPS) control is one such control technique with an extra degree of freedom to minimize the backflow power (BFP) and inductor peak current, which claims to be superior to SPS control. In this analysis, functions for BFP and peak current in SPS and EPS control for both buck and boost operations, considering all possible cases of the inductor current waveform are derived. The two control variables of EPS control are reduced to a single control variable to minimize BFP and peak current. To identify the most efficient control technique between SPS and EPS control, efficiency analysis is carried out over a wide voltage and load range.