Design and controller implementation of 3.3 kW bridgeless boost-fed three-level resonant converter for EV battery charging

This paper presents the systematic design methodology of a 3.3 kW, level 2 battery charger with improved grid power factor for EV applications. The charging of the battery bank from the utility grid through bridgeless interleaved boost (BIB) converter and the proposed three-level modified series–parallel resonant converter is explained in detail. The proposed topology offers low voltage stress equal to half of the DC link voltage across the switches as three-level is implemented in the resonant stage. The transformer parasitics are taken into consideration and the design of resonant stage for frequency modulation is elaborated. One of the major concerns of the charging system is the grid power factor which is largely affected by power electronic switching operation. The detailed controller design procedure for power factor correction of BIB and DC link voltage regulation is elaborated in this paper. Simulation results obtained using PSIM software prove that the power factor is close to unity with less supply current total harmonic distortion as per IEC 61000-3-2 standard. The proposed resonant converter switches achieve zero voltage switching for above resonant frequency operation.