Fuzzy logic controller for large, grid-integrated wind farm under variable wind speeds

Abstract

Wind turbines have attracted considerable attention as a renewable energy source due to the environmental concerns and fossil fuel depletion. When connected to existing power systems, wind turbines can cause a number of issues related to the system stability and power quality. Dynamic performance of an electric power grid with wind turbines under variable wind speeds is considered and investigated in this paper. A four-machine-two-area benchmark system has been adopted from the IEEE, and combined with the wind turbines. Wind power generation system with variable-speed provides an opportunity to extract more wind power compared to fixed speed systems. However, the use of variable-speed generators leads to variable output power, frequency and voltage, all due to the wind speed fluctuations. The performance of the output power can be improved if adequate control mechanism is implemented in the system. To maintain the output power, voltage and frequency of system at desired values, a fuzzy logic system is designed as a damping controller for the power output and frequency fluctuations of a variable-speed wind power generation system. Control is implemented by changing the blade pitch angle of the wind turbine. Dynamic modeling, control and simulation study of the two area-wind power generation system is performed using MATLAB/Simulink. The simulation results show that the controlled variables reach required operation values in a very short time, and improve the dynamic response and the transient stability of the power system.