An Integrated Quasi single-stage Isolated Bidirectional Buck-DAB Converter with Full load ZVS Range

In this paper, an integrated Quasi single-stage Buck-DAB (QSBDAB) converter is proposed to ahieve voltage gain regulation with high performance. In the QSBDAB converter a Buck-like voltage regulator unit is constructed by adding an auxiliary inductor and an auxiliary capacitor. With the voltage-matched modulation and voltage regulator unit, the DAB can always work under the conditions that the voltages of both sides of the leakage inductor matched when input or output voltage varies. Thus, ZVS can be achieved of all the switches of the converter under different loads. Compared to the traditional two stage Buck-DAB converter, the proposed QSBDAB converter needs less switches. Besides, the transmitted power of Buck inductor is also less which is beneficial to improve efficiency and power density. Detailed analysis of the working principle, inductor transmitted power characteristics, and the full load range ZVS design are presented. The validity of the proposed converter and the correctness of the analysis are verified by simulation.