Abstract: “This paper presents fuzzy tuned-PI controller to minimize the frequency deviations in a hybrid distributed generation system consisting of wind-thermal along with storage system flywheel energy storage system (FESS) and ultracapacitors. The frequency deviation in the hybrid system in the presence of the controllers like conventional-PI and fuzzy-PI is compared under the presence of FESS/UC under different disturbance scenarios. Step as well as random variation in wind speed and load demand are considered as disturbance input to the above hybrid system. In addition to the graphical results, comparison in terms of the performance indices, settling time, peak overshoot, integral square error (ISE) is also presented. Both graphical and quantitative results clearly show the robustness and better performance of fuzzy based PI controller as compared to the conventional PI for minimization of frequency deviation in hybrid power system”

Keywords: Energy storage system, flywheel energy storage system (FESS), frequency regulation, fuzzy controller, hybrid system, PI Controller, ultracapacitors (UC).