improved robust frequency control strategy in res-based microgrids using virtual inertia and rpcd approach

In modern microgrid systems, maintaining frequency stability in the presence of renewable energy sources remains a critical challenge. this paper presents a resilient frequency control strategy that incorporates virtual inertia to mitigate instability issues arising from the fluctuations of renewable generation. the proposed method is based on the robust polynomial-based control design (rpcd), which is tailored for microgrid applications to handle inherent system uncertainties. in addition, the h∞ control method is utilized as a benchmark to evaluate system performance under disturbances. the study considers distributed generation from solar and wind sources and analyzes the system’s dynamic behavior in both grid-connected and islanded operating modes. in the islanded scenario—triggered by events such as voltage drops or frequency mismatches—the performance of the developed rpcd-based scheme in preserving system frequency is thoroughly evaluated. furthermore, to investigate potential enhancements in local control performance, a version of the system with optimized pid parameters using the shuffled frog leaping algorithm (sfla) is also examined. the results confirm that the proposed controller, with and without optimization, successfully ensures system stability under diverse and challenging operational conditions.