Double step-down dual active bridge DC-DC converter

A double step-down dual active bridge converter with high voltage gain and high efficiency is proposed in this paper. The proposed converter achieves double step down function by adding only one capacitor at the primary side of transformer. Moreover, the three switches at the primary side has reduced voltage stress and the proposed converter operates in a wide ZVS range under light load. Additionally there is no transformer saturation problem by the addition of this capacitor. Hence, it removes the need of additional control scheme and circuit which improves the efficiency of the system in terms of cost and complexity. Moreover, by applying trapezoidal scheme at transformer primary side, two low side switches of proposed converter has improved turn-off loss. A 4 kW prototype converter is constructed to verify the performance of the proposed converter.