Improved speed regulation and mitigation of drive-train torsion fatigue in flexible wind turbines, using disturbance utilization control: Part two

Modern wind turbines are experiencing rapid growth in both physical size and rated capacity. As wind turbines grow larger with necessarily lighter construction materials, dampening flexible modes with active control becomes more critical. In this paper we apply the theory of ldquodisturbance utilization controlrdquo (DUC) to a 600 kW upwind machine to dampen drive-train torsion while regulating generator speed. We show that positive ldquoutilityrdquo exists in turbulent wind inflow, and we demonstrate that the optimal DUC controller achieves decreased pitch actuator demand and improved drive-train fatigue life through dampening of torsion oscillation. In part one of this paper we provided an overview of previous disturbance accommodation control (DAC) approaches to wind turbines, and we discussed the modes of operation in DAC. Results for DUC are presented in this part two and compared to a previously published controller.