Modelling and Design of Grid Synchronised Three Phase Single Stage Battery Charging Station

Abstract

Electric vehicles (EVs) are a suitable alternative to conventional fuel-based IC engine vehicles in view of global warming concerns. The fast-charging infrastructure interfaced with the utility grid is the mandatory requirement to promote EV adoption aggressively in the world. However, fast charging inversely impacts the grid in terms of injected harmonics and degrades the grid's power quality, demanding careful evaluation to protect the grid consumer interest. Targeting the power quality shaping, the presented work in this paper describes the model of a grid interfaced fast EV charging station. The charging station consists of an active front-end rectifier (AFER) connected to the grid through filter inductance. The output of AFER is connected directly to the DC bus, where EVs get connected through battery chargers. The AFER has operated in closed-loop control with inner current control (constant current control with power factor correction) loop and outer DC voltage control loop. The efficient controller with AFER is responsible for delivering the DC power to the battery at improved power factor and power quality. The proposed control technique efficacy is validated using MATLAB simulation by charging the battery in constant current (CC) and constant voltage (CV) mode.