Enhanced Frequency Regulation in Low-Inertia Microgrids Using PID-Based Virtual Rotor Control with EV and DR Support

This paper presents a robust control strategy to address the frequency regulation challenges in low-inertia microgrids (MGs) with high penetration of renewable energy sources (RESs). A novel PID-based Virtual Rotor Control with Integral feedback (PID-VRC/I) is proposed to emulate virtual inertia using Electric Vehicles (EVs) and to mitigate the adverse effects of measurement delays caused by the phase-locked loop (PLL). To ensure reliable frequency support during periods when EVs are unavailable, a coordinated demand response (DR) mechanism is integrated as a backup control layer. The DR framework considers flexible loads such as pumps, chillers, compressors, and Uninterruptible Power Supply (UPS) systems, all controlled using a conventional VRC approach while taking into account their communication and response time delays. A modified zebra optimization algorithm (MZOA) is employed to optimize the proposed controller gains. The effectiveness of the proposed control framework is validated through two scenarios using hardware-in-the-loop (HIL) testing on the Real-Time Digital Simulator (RTDS) platform. Results demonstrate that the proposed PID-VRC/I with DR strategy significantly outperforms conventional VRC configurations by reducing frequency deviations, enhancing dynamic response, and minimizing stress on EV systems.