Time-varying control of wind turbines

This paper introduces the use of time-varying modern control theory for wind turbine applications. The dynamics of an operating wind turbine are periodic in time due to the rotational motion of its blades. One cannot then use common linear time-variant control principles to guarantee closed-loop stability or desirable performance. Periodic state-space control can be employed, whereby both the feedback gains and state estimator are periodic. Such ideas have been utilized in simulation studies to yield superior results for multi-objective problems.