Ziegler-Nichols based controller parameters tuning for load frequency control in a microgrid

This paper deals with the load frequency control of a small scale microgrid consisting of wind, solar, diesel generator and fuel cell as power generating sources and battery, flywheel and aqua electrolyzer as energy storage elements. To improve the load frequency control, the controllers are properly tuned so as to reduce the mismatch between the real power generation and the load demand leading to minimum power and frequency deviations. A systematic approach to obtain frequency bias parameter followed by tuning the gains of Proportional, Integral and Derivative controller (PID) using Integral Square Time Error evaluation criterion (ITSE)and Ziegler Nichols method respectively is proposed. The simulation studies are carried out for different cases and it is found that the dynamic responses of the frequency and power of the microgrid is quite acceptable.