Backflow Power Optimization of DAB with Gradient Descent Algorithm Based Extended-Phase-Shift Control in EER Application

To reduce the backflow power of dual-active- bridge (DAB) DC-DC converter and improve the operating efficiency, this paper proposes a gradient descent algorithm (GD- EPS) based extended-phase-shift (EPS) control. Firstly, the transmission and backflow power models of DAB converter with EPS and single-phase-shift (SPS) control are established, and the influencing factors of backflow power are analyzed. Secondly, according to the backflow power model, the gradient descent algorithm for solving the optimal solution of backflow power is obtained. On this basis, the output voltage closed-loop control is added to derive the DAB overall optimal control scheme. At last, the simulation models of DAB converter with GD-EPS and SPS control are built and compared, it is verified that the GD-EPS control can optimize the backflow power better than the SPS control when the load and input voltage change.