Dual-Transformer-Based DAB Converter with Controllable Integrated Inductances

A dual-transformer-based dual active bridge (DT DAB) converter is proposed in this paper. The proposed DT DAB has small input current ripple and a wide voltage range because the magnetizing inductances of the dual transformers can be used as the input filter inductances at the same time. In addition, the zero-voltage-switching (ZVS) of all switches in the full load range under wide range input voltage variation can be realized. Unlike the previous three-winding-coupled-inductor-based DAB converter, in the proposed DT DAB converter, the magnetizing inductances and leakage inductances can be all integrated into split UI cores based dual transformers and controlled accurately. Moreover, the split UI cores can reduce the layers of PCB windings, a low-profile design can be achieved. Furthermore, to obtain the magnetic integration design with low loss, a systematic design methodology for the planar integration magnetics is introduced to make a tradeoff between efficiency and power density. Finally, the validity of the proposed topology and design is verified by experimental results from a 1-kW laboratory prototype.