Sliding mode control based robust observer of aerodynamic torque for variable-speed wind turbines

This paper focuses on a robust power generation control strategy for a variable speed wind energy conversion system. The proposed control strategy, by a robust observer of the aerodynamic torque, produces the required generator electromagnetic torque. The robust ultimate boundedness of the observation error and the tracking error, with arbitrary precision, is proved. The proposed sliding mode control approach has been validated on a 1.5-MW three-blade wind turbine using the National Renewable Energy Laboratory (NREL) wind turbine simulator FAST (Fatigue, Aerodynamics, Structures, and Turbulence) code. Reported numerical simulations show that the proposed control solution is effective in terms of optimal power extraction and it is robust with respect to disturbances affecting the system.