Single Stage Switched Inductor SEPIC Based Charging System for LEVs

A high power factor enhanced power quality single stage charging system is put forward for the light EVs (LEVs). A switched inductor configuration is utilized in the conventional SEPIC converter for improving the static DC voltage gain of the converter, especially at high line voltage. This single stage charger provides unity power factor (UPF) operation and low harmonics distortion at the supply. The voltage follower approach is utilized for emulating the characteristics of the charging process as a resistive load, at the grid. The discontinuous conduction mode (DCM) of the output inductors in each switching cycle, reduces the required magnetic size of the inductors as well as the sensing devices. Moreover, the zero current switchings of the switches further improve the losses in the charger. The analysis along with the design methodology is presented to elaborate charger operation in DCM condition. A wide range of supply voltage, is considered for ensuring the safe operation of the charger during voltage fluctuations. Moreover, the hardware implementation of the charger is carried out at the power level of 450W and test results are provided to verify charger performance in steady stage and dynamic conditions.