Robustness Analysis of Primary Frequency H∞ Control in Stand-alone Microgrids with Storage Units

This paper presents a robust H∞ control design approach for primary frequency regulation in isolated microgrids (MGs). MGs consisting of diesel generators, photovoltaic (PV) panels, and storage units are here considered. Starting from given desired design specifications, a multi-variable H∞ controller is designed via the linear matrix inequalities (LMI) method. In the second step, uncertainty in the storage device state of charge (SoC) is considered and a robustness analysis using µ-analysis is carried out in order to determine its maximum variation range for which the control performances imposed are respected for the considered operating point. MATLAB®/Simulink® time-domain simulations validate the controller's robustness and performance in the presence of various load disturbances and SoC uncertainty.