Modeling and Analysis of Hybrid Dual Active Bridge Converter to Optimize Efficiency Over Whole Operating Range

To improve the efficiency of hybrid dual active bridge (HDAB) converter with a half-bridge structure on the primary side and a full-bridge structure on the secondary side over the entire operating range, this article proposes a novel four-degree-of-freedom (4-DOFs) modulation scheme by taking full advantage of the respective structural characteristics of the half bridge and full bridge. First, a universal steady-state model of the HDAB converter with the 4-DOF modulation scheme is established in the frequency domain, revealing the relationship between modulation DOFs and steady-state quantities. Then, the optimal four-DOF (O4-DOF) modulation scheme is obtained for minimizing the inductor root-mean-square (rms) current with the help of the particle swarm optimization (PSO) algorithm. Compared to the conventional phase shift modulation (PSM) scheme, the proposed O4-DOFs modulation scheme greatly improves the converter efficiency. Finally, the correctness of the theoretical analysis is verified by building an experimental platform with an input voltage of 400 V, an output voltage of 100–200 V, and an output power of 1 kW.