A Multi-Mode Control Based Asymmetrical Dual-Active-Bridge Series-Resonant DC-DC Converter (DABSRC)

A multi-mode control for asymmetrical dual-active-bridge series-resonant DC-DC converter (DABSRC) based on half-bridge and full-bridge switching configurations is proposed. The proposed control is configured to eliminate burst-mode operation while supporting an efficient wide-voltage range voltage variation handling and bidirectional power-flow capabilities. Under heavy and medium load conditions, the proposed control method regulates converter's output by varying the switching frequency. When switching frequency exceeds its predetermined maximum value under light load conditions, a second control mode is employed (instead of opting for burst mode) where the switching frequency is fixed to maximum value and converter output is regulated by varying both the phase shift and duty cycle. The effectiveness of the proposed method is validated by experimental results with the peak efficiency of 98.95 % and power density of approximately 218 W/in(3) or 13.3 kW/L (including output filter and auxiliary-power circuit).