An Improved Control Strategy for DFIG Wind Turbine to Ride-Through Voltage Dips

This paper suggests a control strategy to improve the ride-through capability of doubly fed induction generator (DFIG) based wind turbine connected to the grid. In order to provide a suitable control for DFIG under grid disturbances such as voltage dip, a nonlinear model of DFIG which takes the stator flux dynamics into consideration is developed. At first, a feedback control law based on input output feedback linearization (IOFL) is used to transform the nonlinear model of DFIG into two decoupled systems in the canonical linear form. Then, PI controller is designed to control the rotor currents. The performance of the proposed control strategy under voltage dip is tested through simulation of a 1.5 MW DFIG and compared with conventional vector control.