STATIC OUTPUT FEEDBACK ROBUST LOOP SHAPING CONTROL FOR GRID CONNECTED INVERTER USING GENETIC ALGORITHMS

At present, robust analysis is an important issue for designing controllers in inverter-based distributed generation systems. In these systems, the fluctuation of DC voltage level from renewable resources (e.g., fuel cells, solar cells, wind turbines) and loading conditions cause system uncertainties and disturbances. To enhance the robust performance of the DG systems, a new class of inverter controller is required to achieve both robustness and performance of entire systems. In this paper, the proposed technique applies Genetic Algorithms (GA) to determine the optimal controller parameters so that stability margin of the controlled system is maximized. In addition, the structure of (Proportional-Integral-Derivative) PID with first order derivation filter is selected as the final controller to realize a practical robust controller. As results indicated, stability margin of the proposed controller is better than that of the reduced order controller designed by Hankel Norm model reduction. The proposed technique, hence, offers a robust controller with a guaranteed stability margin; also it is practically feasible to be implemented.