Deep Reinforcement Learning Based Secondary Control Strategy for Islanded Microgrids
摘要
This paper proposed a novel distributed secondary control strategy for islanded alternating current (AC) microgrids to compensate for frequency and voltage deviations caused by primary droop control. The strategy adopts an “offline training–online deployment” reinforcement learning framework to enhance power quality, in which two independent twin delayed deep deterministic policy gradient (TD3) agents are trained separately for frequency and voltage regulation. Based on local observations and information from neighboring nodes, the agents generate control actions in real time to dynamically adjust the droop control. To improve learning efficiency and control precision, a normalized reward function is designed, incorporating deviation magnitude, node consistency, and action penalty. The proposed control system operates without centralized coordination and relies solely on local communication to achieve global cooperation. Simulation results on an islanded microgrid with four inverter-based distributed generators (DGs) demonstrate that the TD3-based controllers significantly reduce frequency and voltage overshoot, shorten regulation time, and decrease steady-state error compared to traditional proportional-integral (PI) controllers. These results verify the superior dynamic response and robustness of the proposed method.