A Zero-Backflow-Power EPS Control Scheme With Multiobjective Coupled-Relationship Optimization in DAB-Based Converter

Dual-active-bridge (DAB) based dc–dc converter is usually chosen for energy conversion. In this article, there exist many coupled relationships such as the controversy between local minimum current stress and transmission power, which influence efficiency promotion greatly. To analyze complicated coupled relationship and obtain the global minimum values, after unifying backflow power and transmission power into one integral function, a novel extended-phase shift (EPS) control based on complete differential algorithm is proposed, which can not only eliminate the backflow power completely, but can also realize a type of multiobjective optimizations including improvement of transmission power and decrease of current stress. Through the proposed method in this article, the efficiency can be improved gradually. Moreover, the coupled relationships among variables are clarified clearly, which can avoid power loss increase during optimization. A DAB-based prototype is established and the experimental results verify the correctness and effectiveness of the proposed method.