Modulation Scheme of Dual Active Bridge Converter for Seamless Transitions in Multiworking Modes Compromising ZVS and Conduction Loss

A modulation scheme for dual active bridge converter is proposed to achieve zero voltage switching (ZVS) and reduce the conduction loss in this article. To compromise the ZVS achievement and the conduction loss, optimized working modes are derived from different cases. Compared with dual phase shift and triple phase shift modulations, the modulation in this article can achieve ZVS in both the light load and the heavy load. Therefore, the switching loss in the light load can be reduced, and the efficiency in the light loads is improved. However, the converter cannot achieve seamless transient among the different optimized working modes, which may cause the transient oscillation in the mode transition. A modulation scheme employing closed-loop control by integrating different working modes is proposed. Furthermore, the seamless transition method among the different working modes is proposed, so the modulation scheme is very suitable to be used for wide battery voltage and wide load requirements. The conduction loss and peak current by using the proposed modulation scheme are compared with those of the previous modulation schemes. With the proposed modulation scheme, both the conduction loss and ZVS can be improved. Finally, a 1.2-kW experimental prototype has been built to verify the effectiveness of the proposed converter and the modulation scheme.