Novel transformer-flux-balancing control of dual-active-bridge bidirectional converters

In this paper, a novel flux-balancing method for the isolated dual-active-bridge (DAB) bidirectional converter based on direct control of the magnetizing current is proposed. In the proposed method, the dc component of the primary and secondary current is controlled by providing two control loops; one to keep the average magnetizing current approximately zero and the other to keep the average primary and secondary current approximately zero. The performance of the proposed flux-balancing control is experimentally evaluated on a 3.3-kW DAB prototype designed for automotive applications.