Improved Switch Model Accuracy in Dual Active Bridge Converter Small Signal Modeling

In this paper, a new reduced-order average model (RAVM) for a DAB converter is presented. The model can be applied to all modulation techniques, such as Single-Phase-Shift (SPS) modulation, Extended-Phase-Shift (EPS) modulation, Dual-Phase-Shift (DPS) modulation and Triple-Phase-Shift (TPS) modulation. In the proposed model, conduction losses, inductor losses, transformer losses, switching losses with input/output filters are considered to improve the accuracy of modeling. This article employs a virtual resistance for switching power losses to model the large and small signals of the dual active bridge converter with triple-phase shift modulation. Using this virtual resistance enhances the accuracy of modeling and better estimating converter efficiency and losses, especially at high switching frequencies. The introduced model is successfully implemented in PLECS software and then large and small signal analyses are curried out. Comparison of simulation results under different operating conditions show a suitable accuracy of the proposed model in tracking the behavior of the DAB converter compared to other methods, without considering all the significant elements affecting the converter's performance.