Hybird-bridge Based Dual Active Bridge DC/DC Converter with Wide Voltage Conversation Gain

In this paper, a hybrid-bridge based dual active bridge (DAB) DC/DC converter with a corresponding modulation strategy is proposed for medium voltage applications with a wide voltage conversion gain. The proposed converter is composed of a three-level (TL) full-bridge (FB) with active neutral-point clamping and a two-level FB for interfacing between the medium voltage with low voltage. Compared with the two-level DAB DC/DC converter, the proposed converter has the following merits. 1) The voltage stress on power switches is lower due to the TL structure, which is thus more suitable for medium voltage applications. 2) The wider voltage conversion gain can be achieved thanks to the proposed corresponding modulation strategy with multiple working patterns. Besides, the proposed converter can achieve the zero-voltage-switching (ZVS) for both primary-side and secondary-side power switches. The operation principle, characteristics, and performances of the proposed converter are analyzed in detail. Finally, the simulation results are provided to verify the proposed converter.