An Optimization Method for Solving Three‐Phase Unbalance and Vehicle‐to‐Grid Reactive Power Compensation Utilizing Three‐Phase Inverter Control

ABSTRACT The increasing penetration of electric vehicles (EVs) poses challenges to voltage stability and power quality in distribution networks, especially under three‐phase unbalanced load conditions. This study aims to develop a practical and effective method for mitigating three‐phase unbalance and providing reactive power compensation (RPC) in vehicle‐to‐grid (V2G) applications. The scope of the work focuses on residential distribution networks where V2G charging piles are deployed, considering both balanced and unbalanced operating scenarios. The main contributions are threefold: (1) a realistic V2G AC–DC control scheme based on conventional d – q control is adopted to ensure compatibility with existing charging hardware; (2) a novel three‐phase four‐wire inverter topology and control strategy is proposed to suppress neutral point voltage shift and absorb zero‐sequence current under unbalanced conditions; and (3) an OPF‐based RPC control method is integrated to regulate node voltage and improve voltage unbalance factor (VUF) without affecting user charging requirements. Simulation studies and a real residential case in demonstrate that the proposed approach can maintain node voltage within ±5% of nominal value, reduce VUF to below 2% and provide up to 2176 kVAr of reactive power support, confirming its practical feasibility and effectiveness.