Dual-Transformer-Based DAB Converter With Asymmetrical Power Transmission and High-Power Density for Electric Vehicles

In this article, a dual-transformer dual active bridge (DAB) converter with high power density based on the H5 structure is proposed for electric vehicle applications. Additionally, a new dual-frequency switching strategy is presented. The proposed converter has a higher maximum transmitted power in both charging and discharging states compared to the basic DAB converter. Moreover, the proposed converter operates at a different charging state threshold point than the conventional DAB converter. Therefore, the proposed DAB converter has an asymmetrical power curve characteristic. In this regard, the new structure, principal characteristics, different modes of operation, power transmission and sharing analysis, loss and efficiency assessment, and comparative study have been fulfilled. Finally, the proposed converter, with a maximum charging power of 2600 W and a maximum discharging power of 3300 W, is prototyped and tested at 1500 W to validate the performance of the proposed DAB converter and the accuracy of the presented theoretical analysis for all four states.