Research on Optimal Control Strategy for Dual Active Bridge Converter with Phase Shift Control

The Lagrangian extremum method is a method for obtaining the extremum of a multivariate function whose variables are restricted by one or more conditions. Based on this method, this article has improved the Dual-Active-Bridge (DAB) converter optimization control strategy. Compared with the conventional analytical method, it avoids the process of solving the equations of the external shift compared to D ₂ and the internal shift compared to D ₁ and the voltage regulation ratio, and it also avoids the more complicated closed-loop system design. By discarding the condition that the partial derivative of the Lagrangian multiplier by the function is zero, the intersection point of several planes, that is, the continuous optimal trajectory, is obtained, thereby obtaining the optimal phase shift angle. An experimental prototype is built to compare the inductor current stress under the optimal solution combination with the stress of the non-optimal combination. The experimental results are consistent with the theoretical analysis, which proves the effectiveness and feasibility of the proposed method.