Review on Power Quality Enhancement Using Electric Vehicle Charging Stations with Unified Power Quality Conditioner

Abstract

The rapid integration of electric vehicle (EV) charging infrastructure into modern power distribution systems has introduced significant challenges related to power quality, including voltage sag/swell, harmonic distortion, reactive power imbalance, and load variability. This review paper presents a comprehensive analysis of power quality enhancement techniques using Electric Vehicle Charging Stations (EVCS) integrated with a Unified Power Quality Conditioner (UPQC). The UPQC, a versatile custom power device combining series and shunt active filters, is explored for its capability to simultaneously mitigate supply- and load-side disturbances in EV-dominated grids. The study examines various control strategies, including synchronous reference frame (SRF), instantaneous reactive power (p–q) theory, and artificial intelligence-based controllers, for efficient operation of UPQC in EV charging environments. Furthermore, the role of bidirectional EV chargers (Vehicle-to-Grid, V2G) is discussed in supporting grid stability and improving overall power quality. A comparative evaluation of existing methodologies highlights improvements in total harmonic distortion (THD), voltage regulation, and system reliability. The review also identifies key research gaps, such as real-time adaptive control, integration with renewable energy sources, and scalability challenges in smart grid frameworks. The findings demonstrate that the coordinated use of EVCS and UPQC offers a promising solution for enhancing power quality in future intelligent power systems.