A Bridgeless Isolated Half Bridge Converter Based EV Charger with Power Factor Pre-regulation

Cconventional full bridge and half bridge converters are quite popular for front-end power factor pre-regulation (PFP) in EV (Electric Vehicle) battery chargers. DCM operation at high power causes increased oscillation in the circuit. These oscillation increase with parasitic components of circuit. During deep DCM operation, these oscillations are seen to be significant and contribute to harmonic content in the input current. Therefore, a power factor pre-regulation bridgeless isolated half bridge (HB) converter based electric vehicle (EV) charger with reduced LC oscillation in discontinuous conduction mode (DCM), is presented in this paper. To reduce LC oscillation, two diodes are used in series with minimum number of magnetic components. The design of proposed charger in DCM is illustrated to facilitate uniform battery current during constant current/constant voltage (CC-CV) charging. The inherent advantage of reduced conduction loss with bridgeless topology are achieved. The performance of this isolated HB converter based charger is shown for improved oscillation characteristics and power quality (PQ) operation at steady state and over a range of varying input voltages.