Exploiting bend-twist coupling in wind turbine control for load reduction

The ever-increasing dimensions of wind turbines are associated with higher structural loads. Therefore, there is a demand for advanced load reduction techniques. In the design of rotor blades, the bend-twist coupling effect is used for passive load reduction. This research shows how this effect can be augmented with active load reduction through controls that exploit bend-twist coupling. The twist rate of the rotor blades is utilized for gust detection. In addition to regular closed-loop pitch control, the twist rate is used to adjust the collective pitch angle using feedforward control. Extreme loads for flap-wise bending moment can be reduced on average by up to 6 % and tower acceleration is reduced by 15 %. Overall, this method is suitable for reducing extreme loads while maintaining fatigue damage compared to the reference case.