Comparison of Frequency Controllers for Frequency Control of PV Generator in a Grid Interconnected PV-Diesel System
Frequency is an important parameter which is to be controlled in a power system. In PV system power is fluctuating in nature due to changing insolation condition . Hence frequency has to be controlled . Fluctuating PV power causes frequency deviations in the power utilities when the penetration is large. Usually, an energy storage system (ESS) is used to smooth the PV output power fluctuations and then the smoothed power is supplied to the utility . Here, PI based frequency controller is implemented which is a fixed gain feedback controller. Then it is compared with a fuzzy based frequency controller ; Where fuzzy control is used to generate the PV output power command. This fuzzy control uses average insolation, change in insolation, and frequency deviation as the inputs. Fuzzy based frequency controller is found to be effective in performing duties like frequency control . PI Controller cannot compensate the parameter variations like insolation variations. They cannot adapt to changes in the environment. The settling time and peak time of PI controller is found to be more than Fuzzy controller. Simulation results shows that fuzzy based controller is more effective than conventional PI controller..Simulation platform used is MATLAB simulink.
Divya Raj , Daru Anna Thomas