Robust sliding mode control of a DFIG variable speed wind turbine for power production optimization

A cascaded nonlinear sliding mode controller is proposed for power production optimization of a variable speed wind turbine equipped with a Doubly Fed Induction Generator (DFIG). The inner loop controller ensures a robust tracking of both generator torque and rotor flux, while the outer loop controller achieves a robust tracking of the optimal blade rotor speed to optimize wind energy capture. The global controller is firstly tested with a simplified mathematical model of the aeroturbine and DFIG for a high-turbulence wind speed profile. Secondly, the aeroturbine controller is validated upon a flexible wind turbine simulator. The obtained results show better performance in comparison with the existing controllers in presence of parameters variations.