On-Board Battery Charger Based-on Multifunctional Two-Stage Topology for Electric Vehicles

This paper proposed a multifunctional two-stage topology based on-board charger (OBC) for electric vehicles (EV s). The proposed two-stage topology is composed of three independent front-end ac-dc converters that are utilized to provide the dc input for three independent back-end dc-dc converters. The output side of the back-end converters are connected in parallel to reduce the components rating and increase reliability of the OBC. Single active bridge (SAB) with LLC resonant tank is utilized for each back-end converter to reduce the switching losses and improve the charger efficiency. Moreover, the proposed front end-converter can be connected to either three-phase supply, and behave as level ‘2’ charger, or single-phase supply to operate as level ‘1’ charger. Only two transfer switches are used to connect the input terminals of the three front-end converters in parallel to the single-phase supply. This action enables interleaved operation of the proposed converter. Furthermore, the proposed control algorithm for the front-end converter regulates the charging voltage and current, keeps sinusoidal supply current with a high power factor, and maintains balanced three-phase supply currents. The proposed OBC is simulated using PSCAD/EMTDC to verify the dynamic performance and to demonstrate the multifunctional operation of the control algorithm.