Robust MG control considering uncertain constant power load

Abstract

The destabilization of Microgrids (MGs) is attributed to the negative incremental resistance of constant power loads (CPLs). Furthermore, the inadequately damped modes of the droop control, typically employed for distributed generation (DG) power sharing, contribute to disturbances in MG dynamic performance. This paper introduces a novel control strategy aimed at mitigating instability issues associated with both CPL and droop controllers in MGs. The proposed approach utilizes an optimized H∞ control scheme, incorporating the Whale Optimization Algorithm (WOA), to enhance stability on both the CPL and distributed generation (DG) sides of the MG. The proposed controller is modeled and validated through comprehensive simulations in MATLAB, demonstrating its effectiveness under various uncertainty scenarios and disturbance conditions. These simulations demonstrate the controller's capability to effectively mitigate disturbances, optimize DG power sharing, and regulate the DC voltage of the CPL, thereby enhancing overall microgrid stability and performance. Additionally, a comparison between the proposed robust H∞ and conventional droop control schemes highlights the superiority of the proposed approach, with results confirming improved MG dynamic performance. The proposed controller exhibits a notable enhancement in Minimum Voltage Deviation (MVD), showing a substantial improvement of 96.19%. Additionally, both the Critical Response Time (CRT) and Settling Response Time (SRT) witness significant improvements of 95.33% and 97.69%, respectively, when subjected to system disturbances. Finally, the implemented MG is validated on a Real-Time Digital Simulator (RTDS), affirming the practicality of the proposed compensation technique.