Wind Turbine Tower Vibration Reduction by Individual Blade Pitch Control

Abstract

Over the last decades, wind energy is becoming a feasible solution to cope with the growing power demands still offering a way to avoid CO2 generation. This technology presents several benefits but also technical challenges. One of these challenges relate to the increasing tower loads with increasing turbine size. This work focuses on the possibility of reducing the tower loads using a pitch control system to damp the oscillations of the tower. A non-linear system model is first established for an on-shore wind turbine plant. A linearized state space model is then computed on the form of a linearly time varying problem. A number of transformations are then evaluated in order to attempt to remove the linearly time-varying behaviour to reduce the problem into a formulation with matrices which are constant in time. Some preliminary work on the design of a controller is presented.