Improving Middle Load Efficiency of Dual Active Bridge Convertors using Coupled Inductors

In this paper, a method of switching a circuit in three regions (light load, middle load, and heavy load) by using coupled inductors as auxiliary inductors is proposed. The efficiency of the proposed circuit can be improved by up to approximately 2.8pt while maintaining the ZVS range expansion via simulations. In addition, because the core can be shared by coupling the auxiliary inductors, the circuit size can be smaller than that obtained when two non-coupled inductors are used to vary the auxiliary inductance value.