Individual Pitch Control for Variable Speed Turbine Blade Load Mitigation

Dynamic load is a key consideration in large scale wind turbine design. It is approved that the performance of controller can distinguish impact wind turbine loads. During pitch control algorithm design, if load influence is considered, it will be benefit to lower cost of whole wind turbine and extend longevity. In this paper, an individual pitch controller is developed based on a kind of Model Free Control strategy, to mitigate the blade root load for variable speed wind turbine. The measured blade root bending moment is taken as one of the inputs of the controller, and the three pitch demand as the controller output. The control strategy was simulated in Bladed external controller based on a 3.0MW doubly fed variable speed wind turbine model, the simulation result verified it's feasible and effective. The Blades root load is mitigated evidently compared to classic collective pitch control.