A Fuzzy Control Based Coordinated Method for Isolated Power Utility Connected Clustered Photovoltaic Systems to Provide Frequency Control

A Photovoltaic system´s output power is not constant and fluctuates depending on weather conditions. Fluctuating power causes frequency deviations and reduction in reliability of the isolated power utility or micro grid when large output power from several Photovoltaic systems is penetrated in the utility. In this paper, to overcome this problem, a simple coordinated control method for clustered Photovoltaic systems is proposed to provide the frequency control. Here, output power command is generated in two steps: central and local. Fuzzy control is used to generate the central output power command considering average insolation, change of insolation, and frequency deviations. In the local step, a simple coordination is maintained between the central power command and the local power commands by producing a common tuning factor. The proposed method is compared with the method where extracted maximum power is supplied to the utility. Simulation results show that the proposed method is feasible to reduce the frequency deviations of the isolated power utility and delivers the power near maximum Photovoltaic power.