Modeling and control of a doubly fed induction generator for grid integrated wind turbine

This paper presents the modeling, simulation and control of a grid connected doubly fed induction generator (DFIG) coupled with the wind turbine. Among all the renewable energy resources, wind energy is rapidly gaining interest of developed as well as underdeveloped countries. Due to the increase in demand of electrical energy and increase in environmental pollution the use of wind energy to meet the domestic and industrial power demands is essential and inevitable. The main benefit is the production of economically justified and ecofriendly energy in bulk quantity. Because of the irregularity of wind speed, the output of wind turbine varies and that is why, variable speed wind turbines are more practical these days. In order to integrate the variable output of the wind turbine with the power grid, doubly fed induction generators are used due to their inherent advantages like active and reactive power control, absence of large capacitive banks and improved power quality. A DFIG is modeled using the electric equivalent circuit and dq₀ transformation along with the stator flux oriented vector control approach is used to decouple active and reactive power. Back to back power converters serve the purpose of controlling active and reactive powers at sub/super synchronous speeds. So the implementation of the proposed scheme ensures the constant output frequency and voltages with the control of active and reactive power and is highly suitable for grid integration in Distributed Generation (DG) Applications. The proposed scheme is implemented in SIMULINK / MATLAB environment and the simulation results validate the efficacy of the proposed scheme.