A Multiphase AC–DC Converter With Improved Power Quality for EV Charging Station

Abstract

This work presents a multiphase ac–dc converter-based electric vehicle (EV) charging station that is designed to meet IEEE-519 power-quality (PQ) standard. The proposed EV charging station draws current from the utility grid at low total harmonic distortion (THD) and high power factor (PF), without using PF corrector and active/passive filter circuits. This study evaluates an 18-phase ac–dc converter for an EV charging station, which consists of three single-phase multiwinding transformers (MWTs) and diode rectifiers. MWTs are connected to enable direct conversion of a three-phase utility supply into an 18-phase power supply that reduces the measured THD in the input line current. The ac–dc conversion stage of the proposed EV charging station is found to be reliable and operates at line-frequency, without the need for high-frequency active switches. For charging an EV in constant current (CC) and constant voltage (CV) mode, a multiphase (interleaved) dc–dc converter is used. MATLAB/Simulink environment is used to evaluate the performance of the proposed EV charging station in terms of THD and PF. The results are validated through an on-the-bench prototype hardware setup of the proposed EV charging station.