Active damping of torsional vibrations in the drive train of a DFIG wind turbine

Torsional vibrations in the drive train of the doubly-fed induction generator (DFIG) based wind turbine can cause large mechanical stress and reduce the life cycle of the components. They can be easily induced by sudden changes from the turbine rotor side or grid side. In this paper, a model-based active damper of the torsional vibration designed with the linear-quadratic-Gaussian (LQG) algorithm is proposed. The modelling of the drive train takes the flexibility of the rotor blades into account and utilizes a three-mass model. A combination of different simulation packages, namely FAST (Fatigue, Aerodynamics, Structure, Turbulence) and Matlab/Simulink describing important dynamics of both the mechanical and electrical side, is applied to analyse the vibrations in the drive train and test the algorithm. Simulation results show that the proposed active damping can suppress the torsional vibrations in the drive train effectively even if a gird fault occurs.