Model-free control for variable-speed wind energy conversion systems based on power tracking

This paper deals with the power generation control in variable-speed wind turbines. These systems have two operation regions which depend on wind turbine tip speed ratio. In this work, we propose the use of model-free control strategy to ensure the maximum power extraction in the low-wind speed region. This control approach offers attractive features such as strong robustness against unmodeled dynamics and easy parameters tuning since it is based on the so-called ultra-local model and the intelligent PID. An algebraic estimator of the ultra-local dynamics is introduced to get rid of the unavailability of accurate wind turbine model and easily implement the proposed control law. The suggested model-free control method has been tested on a 1.5MW three-blade wind turbine utilizing the Fatigue, Aerodynamics, Structures, and Turbulence wind turbine simulator from the National Renewable Energy Laboratory. The outcomes of this validation compared to the industry-standard approach indicate that the proposed control approach is efficient in power tracking.