Stability Analysis and Design of Common Phase Shift Control for Input-Series Output-Parallel Dual Active Bridge With Consideration of Dead-Time Effect

Input-series output-parallel (ISOP) connected dual-active-bridge (DAB) converters allow the use for occasions requiring high input voltage and galvanic isolation with bidirectional power capability. However, when DAB converters are ISOP connected, the traditional analysis without consideration of the dead time cannot effectively explain the reason why the ISOP converter system is stable under common phase shift control (CPSC) when parameters are mismatched. In this article, it is first revealed that the stability of the ISOP DAB converter under common phase ratio control can be ensured by consideration of the dead time. Based on the analysis of the DAB power transmission characteristics with consideration of dead time, a new model is derived for the ISOP DAB converter, which can reveal the reason why the converter can operate stably under CPSC when the design parameters of the individual module are mismatched. Then, based on the derived model, the stability analysis and the parameters design are further performed. Finally, the effectiveness of the working principle and analysis is verified through results from a two-module ISOP experimental prototype.