A novel approach for hybrid pitch control with load reduction of wind turbine based on wind condition classification

While larger wind turbines are capable of more efficient utilization of wind power, more dedicated methodologies for load reduction are needed to ensure and improve the safety and reliability of large-scale wind turbine systems. The well-known individual pitch control is an effective approach to alleviating load in Mx of the hub, but, it usually impairs the performance of tower vibration control, especially under transient wind conditions. In this work, a hybrid pitch control scheme based upon wind condition classification is developed for load mitigation of large-scale wind turbines. The novelty of this method lies in the fact that it allows for the control strategy to be designed for different wind condition including a transient wind condition that can be easily determined by the proposed nonlinear SVM. This method also skillfully avoids using wind speed in control scheme that cannot be measured accurately. It is shown that the proposed method not only inherits the advantages of individual pitch control, but also is capale of reducing the extreme load acting on the hub significantly, thus prolonging the life of wind turbines. Simulations based on BLADED and Simulink validate the effectiveness of the proposed strategy.