Individual Pitch Control of A Clipper Wind Turbine for Blade In-plane Load Reduction

This paper proposes an H∞ individual pitch controller for the Clipper C96 2.5 MW wind turbine installed at University of Minnesota. Different with existing results aimed to mitigate the blade out-of-plane loads, the proposed controller focuses more on reducing the blade in-plane loads. This is because the in-plane loads are dominating parts on the blade roots and therefore more critical to the life time of blades. To better balance the load reduction performance of different components on the turbine, the proposed controller takes the sum of filtered measurements of both blade in-plane and out-of-plane moments as feedback signals. It is expected to mitigate part of the in-plane periodic loads. Meanwhile, the high pass filtered measurements of the out-of-plane moments allow the controller to still mitigate high order harmonic terms of the out-of-plane loads. Therefore, the load reduction performance on the rotor shaft and nacelle should be improved. Simulation results show that the proposed design achieved these objectives.