Switched capacitor and coupled inductor based high power factor charger for E-2/E-3 wheelers

Abstract

This paper introduces a modified Zeta converter topology designed specifically for charging low voltage electric vehicles (LVEVs), enhancing performance for electric two (E-2) and electric three (E-3) wheelers. Unlike traditional Zeta converter, which offers buck-boost gain, an AC-DC converter in this study, utilizes a switched capacitor configuration to efficiently step-down voltage in a single phase, bridging the gap between the AC grid and low potential battery assemblies. This design incorporates a coupled inductor structure and operates in discontinuous inductor current mode (DICM), reducing the size of magnetic components and overall dimensions of converter and power factor correction (PFC) rectifier. DICM operation provides intrinsic PFC and minimizes switching losses, ensuring exceptional grid-side performance with unity power factor and minimal input current harmonic distortions, while maintaining an optimal battery charging profile. The meticulously developed hardware prototype, rated at 450 W, features precise component selection and carefully designed modes of operation. Performance analysis reveals a converter peak efficiency of 94.7 %, total harmonics distortion (THD) in input current at 2.7 % under rated conditions, and near unity power factor with zero phase displacement between input voltage and current.