Multi-objective efficiency optimisation of DAB converters

With the advancement of power semiconductor devices, the dual active bridge (DAB) converter has become widely utilized and demands higher working efficiency. By controlling zero voltage switching (ZVS) of all switching tubes and optimizing current stress and reflux power, the transmission efficiency of DAB converter can be improved under certain transmission power conditions. Firstly, operating modes are categorized based on converter's working conditions, followed by a detailed analysis of inductance current constraints to achieve ZVS under each mode and obtain the transmission power range. The impact of soft switch constraint conditions on transmission power is compared and analyzed for various mode operation scenarios to select the optimal working mode using maximum soft switch power range. To further enhance DAB converter's efficiency, constraint conditions combined with cost function are established to optimize current stress and reflux power within soft switch range resulting in an optimized shift ratio at a specific transmission power level. Finally, simulation platform verifies proposed algorithm effectiveness.