Enhanced operating strategy for a three-phase dual-active-bridge converter including frequency variation

Recently, it has been shown that the operating modes of a three-phase dual-active-bridge (3ph-DAB) DC-to-DC converter can be altered. This can be used in particular to enhance low load efficiency. The different operating modes show significant differences concerning the utilization of the core material and the required filter effort. In this paper, an enhanced operating strategy including a dynamic variation of the switching frequency is investigated to further optimize the performance of the converter. For a specific electric vehicle application, the efficiency of certain operating points is boosted by up to 1 %. The proposed concept is highly beneficial as it affects the operating points with the highest losses, which potentially reduces the cooling effort.