Use of reduced-order observers for feedback control in large wind turbines may reduce fatigue damage from excitement of flexible modes

While full-order observers have been successfully applied in state-space blade-pitch control of large wind turbines, the use of reduced-order observers has, apparently, not been documented. Using a model of a 600kW horizontal-axis wind turbine, we demonstrate that the use of a reduced-order observer to obtain wind speed estimates for disturbance accommodation control may dampen flexible modes and lead to reduced structural fatigue in large wind turbines.