Droop Control and Active Power Filter Coordination in Low-Voltage Microgrids With Ev Charging Stations

Abstract

The increasing deployment of nonlinear loads (NLLs) such as electric vehicle (EV) chargers and renewable energy inverters has raised serious power quality concerns in low-voltage microgrids (MGs), particularly due to harmonic distortions. To address these challenges, this paper proposes a coordinated control strategy that integrates droop-controlled inverters with a decentralized active power filter (APF). The inverters employ a virtual voltage reference generation technique in the αβ-frame, avoiding the need for direct voltage measurements and enabling autonomous operation. The APF is responsible for compensating harmonic currents and reactive power, improving the power quality at the point of common coupling (PCC). A comprehensive stability analysis of the droop control scheme is presented, and damping conditions are derived to ensure robust operation. The proposed system is evaluated under various conditions including islanded and gridconnected modes, using PSCAD/EMTDC simulations. Results demonstrate that the integrated control approach ensures seamless transition between modes, reduces total harmonic distortion (THD), and maintains voltage and frequency stability even under highly nonlinear EV charging conditions. © 2025 Elsevier B.V., All rights reserved.