Robust control based on linear matrix inequalities criterion of single phase distributed electrical energy systems operating in islanded and grid-connected modes

In this paper, a control strategy of a voltage source inverter with LCL filter in distributed electrical energy systems in both operation modes is proposed for microgrids environment. This robust control strategy considers a state feedback controller based on proportional resonant controller using linear matrix inequalities. The controller is able to ensure a good tracking of sinusoidal references and to suppress low order harmonics. It allows to ensure simultaneously a robust stability of the system in front of external disturbances (grid disturbances, load variations), parametric uncertainty (grid inductance) and smooth transition (with no hazardous transients) between grid connected and islanded mode operation. In order to demonstrate the efficiency and performance of the proposed control strategy, a real time simulation using OP5600 from OPAL-RT is used. Several case studies are verified in real time and the results are analyzed and discussed.