Three-Winding-Coupled-Inductor-Based Dual Active Bridge DC-DC Converter with Full Load Range ZVS Under Wide Voltage Range

In this paper, a three-winding-coupled-inductor-based dual active bridge (TWCI DAB) DC-DC converter is proposed. Similar to the current-fed DAB converter, the proposed TWCI DAB has small input current ripple and wide input voltage range. In addition, the zero-voltage-switching (ZVS) of all switches in the full load range under wide input voltage variation can be realized. With the magnetic integration structure, the size of the total magnetics can be reduced, and the efficiency is also increased compared with the discrete magnetic case. To better analyze the working principle of the three-winding-coupled-inductor, a general analysis method based on magnetic reluctance model is firstly introduced to obtain the expressions of high frequency current. Furthermore, ZVS analysis and inductor design to obtain low inductor root mean square (RMS) current and full load range ZVS based on the ZVS conditions, maximum power transfer and RMS current are presented. Finally, the validity of the proposed topology and design are verified by experimental results from a 1-kW laboratory prototype.