ADVANCED UNIFIED CONTROL TECHNIQUE FOR BIDIRECTIONAL GRID-TIED ELECTRIC VEHICLE CHARGERS WITH HARMONIC MITIGATION

Abstract

The rapid adoption of electric vehicles (EVs) necessitates efficient and gridfriendly charging infrastructures. Conventional off-board EV chargers often introduce power quality issues such as harmonic distortion, poor power factor, and voltage fluctuations. This paper presents an enhanced grid-tied off-board EV charger employing a unified control approach to improve power quality. The proposed system integrates a front-end AC–DC converter with active power factor correction (PFC) and a DC–DC converter for battery charging. A unified control strategy is developed to simultaneously regulate DC-link voltage, ensure sinusoidal input current, and achieve constant-current constant-voltage (CC-CV) charging. The system is modeled using state-space techniques, and a multi-loop control architecture is implemented. Simulation results demonstrate significant reduction in total harmonic distortion (THD), near-unity power factor, and stable charging performance under varying grid and load conditions.