DAB unified ZVS control strategy with optimal current stress in full power range under TPS control

Abstract

Current stress and soft switching range are important performance indexes of dual active bridge DC–DC converter. Based on three-phase shift control, Karush–Kuhn–Tucker (KKT) algorithm is used to solve the optimal control strategy of current stress under soft switching conditions, and the interval construction method that KKT cannot solve is given. Aiming at the problem that all or most of the switching devices lose the zero voltage switching (ZVS) soft switching characteristics when the current dual active bridge (DAB) modulation strategy is seriously mismatched in voltage gain or when the output power is relatively small, an optimized modulation strategy is proposed here, which not only realizes the minimum current stress within the full power range, but also ensures that at least six switching tubes can achieve ZVS on–off. The on-state and switching losses of the system are further reduced, and the transmission efficiency of the converter is improved.