An Integrated Electric Vehicle Onboard Charger and Auxiliary Power Module Using a Three-port Current-fed Triple Active Bridge Converter

Onboard charger (OBC) and auxiliary power module (APM) are key components for the charging system of electric vehicles (EVs), which are however usually separately designed thereby occupying significant space. This paper proposes a three-port, current-fed triple-active-bridge (CFTAB) topology that integrates OBC and APM functions into a single dc-dc converter, achieving higher power density and lower cost. Compared to state-of-art integration solutions, the proposed converter features simpler structure, low transformer turn ratio, simultaneous charging at full power capacity, wide voltage range. Three duty cycles and two phase shifts are fully utilized in our proposed control of the CFTAB for zero voltage switching (ZVS) realization and RMS current stress reduction. More importantly, the proposed analytical model provides a simple and fast tool to investigate the properties and performance of the topology for parameter optimization and control design. A prototype is built to verify the proposed design, which provides 11 kW to 250 V∼450 V HV battery and 3 kW to 10 V∼16 V LV battery, with a peak efficiency >96% and a power density >4.5 kW/L achieved.