Model and Control of a Current-Fed Dual Active Bridge Based Ultrawide-Voltage-Range Auxiliary Power Module for 400 V/800 V Electric Vehicles
Liyan Zhu, Hua Bai, Alan Brown
Abstract
As the counterparts of alternators, the auxiliary power modules (APMs) in electric vehicles (EVs) play an irreplaceable role in bridging the high-voltage (HV) propulsion system with the low-voltage (LV) auxiliary system. With the increasing demands of fast charging, the HV propulsion system is seeing an evolution from the 400 to the 800 V 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 article proposed a reconfigurable current-fed dual active bridge (CFDAB) based converter. It accepts a record-wide input voltage from 180 to 900 V and an output voltage from 6 to 16 V. The closed-form solutions of switching current are with consideration of coupled inductor current, the key characteristics of CFDAB, and simple control to secure zero-voltage switching and minimize the switching current. Design implementation is also discussed in this article. A 3-kW prototype with a peak efficiency of 97% was built and tested. The experimental results proved the feasibility of using the proposed topology and control for the ultrawide APM applications.