Dual-Transformer-Based DAB Converter with Controllable Integrated Inductances

A dual-transformer-based dual active bridge (DT DAB) converter is proposed in this article. The proposed DT DAB has a 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 of all switches in the full load range under a wide range of 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 core-based dual transformers and controlled accurately. Moreover, the split UI cores can reduce the layers of PCB windings and 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.