A Current-fed Three-port DC/DC Converter for Integration of On-board Charger and Auxiliary Power Module in Electric Vehicles

On-board charger (OBC) and auxiliary power module (APM) are two major power electronic units in electric vehicles (EVs). OBC is the interface between the grid and HV propulsion battery, and the APM is the bridge connecting the HV system and LV system inside the EV. To save the cost and shirk the size, this paper proposed a three-port current-fed triple-active bridge (CFTAB) converter to integrate OBC with APM both electrically and magnetically. Compared with state-of-art integration approaches, the proposed converter features a simple structure, free of function-select switches, and fewer transformer turns. With the corresponding power decoupling method developed, the proposed topology also allows charging HV battery and LV battery simultaneously. Due to the current-fed nature, there is no need for large output capacitors, and much lower current stress is exhibited. In addition, an integrated prototype for 11kW/250V~450V OBC plus 3.5kW/10V~16V APM is developed to prove the superiorities of the proposed integrated charger.