Model and Control of a Current-fed Dual Active Bridge Based Ultra-Wide-Voltage-Range Auxiliary Power Module for 400 V/800 V Electric Vehicles

As the counterparts of alternators, the auxiliary power modules (APM) in electric vehicles (EVs) play an irreplaceable role in bridging the high-voltage (HV) propulsion system with the lowvoltage (LV) auxiliary system. With the increasing demands of fast charging, the HV propulsion system is seeing an evolution from the 400V to the 800V system. Adapting to such trends, the APM faces the challenge of a much wider input voltage range, particularly in EVs with a reconfigurable battery pack. This paper proposed a reconfigurable current-fed dual active bridges (CFDAB) based converter. It accepts a record-wide input voltage from 180V to 900V and an output voltage from 6V to 16V. Closed-form solutions of switching current with consideration of coupled inductor current, the key characteristics of CFDAB, and simple control to secure ZVS and minimize the switching current. Design implementation is also discussed in the paper. A 3kW prototype with a peak efficiency of 97% was built and tested. Experimental results proved the feasibility of using the proposed topology and control for the ultra-wide APM applications