University of Mohaghegh Ardabili Journal of Operation and Automation in Power Engineering 2322-4576 14 4 2026 12 01 Improving Power Quality in a Microgrid through Control of Active and Reactive Power Output from Inverter-Based Sources 297 307 4177 10.22098/joape.2025.15894.2223 EN Moein Ganjian Department of Electrical and Biomedical Engineering, Mazandaran University of Science and Technology, Babol, Iran. Ali Ghasemi-Marzbali Department of Electrical and Biomedical Engineering, Mazandaran University of Science and Technology, Babol, Iran. Journal Article 2024 09 22 The increasing integration of inverter-based sources in microgrids demands advanced control strategies to maintain power quality by mitigating harmonics and distortion. This study proposes an enhanced control system for grid-connected inverters, integrating a proportional-integral (PI) controller in the synchronous rotating frame with a repetitive control (RC) compensator. A particle swarm optimization (PSO) algorithm is employed to optimize the controller parameters, ensuring effective harmonic suppression. The proposed PI+RC controller is evaluated through simulation studies under various scenarios, including linear and nonlinear loads as well as grid voltage distortion. Results demonstrate a significant reduction in total harmonic distortion (THD), with the proposed controller achieving a reduction from 37.5% to 5.6% under nonlinear load conditions and from 49.5% to 5% when both nonlinear loads and voltage distortion are present. Additionally, the proposed method effectively stabilizes the active and reactive power outputs, surpassing conventional PI controllers. https://joape.uma.ac.ir/article_4177_7284ab61eedeb93566b1fc37efb63422.pdf