Robust Controller Synthesis for Frequency Regulation in Islanded Microgrid

Abstract

Frequency regulation in MG using conventional PID controllers becomes more challenging in the presence of stochastic load and uncertainty in system parameters caused by dynamic perturbation. So, there is a need for a robust controller with acceptable performance and stability for regulating the frequency in MG. The dynamic perturbations include changes in inertia constant and damping coefficient of the power system, which directly affect the frequency of the MG. In this paper, structured H∞ synthesis has been done for robust frequency control in islanded MG. The sources used in MG for compensating the load demand are fuel cell, diesel engine generator and micro-turbine. The robustness and performance of H∞ based controller is validated in the presence of parametric uncertainty and load disturbance caused by stochastic nature of load. The synthesized H∞ based controller is tested for robust stability and performance against ± 50% perturbation of inertia constant and damping coefficient of power system. Simulation results of complete system is also validated with hardware using dSPACE 1104 and control desk