A Reduced Switch High Step Down Gain Bridgeless Coupled Switched Inductor SEPIC HPF AC-DC Converter for LVEVs Charging Applications

A single-switch modified SEPIC bridgeless coupled switched inductor-based charger, for charging applications of low voltage electric vehicles (LVEVs) is demonstrated in this work. Presented charger achieves higher step-down gain between the AC grid and the DC battery pack output without requirement of a step-down transformer, using a coupled switched inductor structure. The discontinuous inductor current mode (DICM) operation of charger reduces the magnetic volume, thus making it compact. The DICM operation adds advantages of inherent power factor correction (PFC) at the input side, without requirement of additional input sensing circuitry. Added to this, DICM operation facilitates zero current turn-on and zero-current turn off for switches and diodes in the charger, respectively, which reduces switching losses associated with high frequency components. Lastly, the design, operating modes and performance of charger is verified through development of a prototype and results obtained are presented in this work.