Hybrid-Type Dual Active Bridge DC–DC Converter for Ultrawide Input-Voltage Range

This article proposes a hybrid-type dual active bridge (H-DAB) topology and extended gain (EG) control method applied to the ultrawide input-voltage range. The H-DAB is obtained by adding an auxiliary half-bridge to the conventional current-fed dual active bridge (CF-DAB) topology. The auxiliary half-bridge can assist the CF-DAB to achieve zero voltage switching (ZVS) on the one hand and further expand the voltage gain range on the other. The proposed EG control expands the input-voltage range of ZVS for all switches by calculating the optimal intermediate bus voltage. In addition, the backflow power has also been drastically reduced. The proposed piecewise control strategy simplifies the complexity of control. The proposed topology and the control method are verified by the experimental results of a 500 W prototype. The input-voltage range is 27–240 V and the output voltage is 375 V. The experimental results proved that the proposed scheme achieves ZVS of all switches in a wide input-voltage range and power range, and the efficiency is improved.