Disturbance observer-based torsional vibration damper for variable-speed wind turbines

This paper presents a robust torsional vibration damper for variable-speed wind turbines based on the disturbance observer method. The damper is designed by explicitly taking into account the pole placement of the closed-loop system in the presence of model uncertainties. Unlike the conventional band-pass filter method, it is analyzed that the proposed method not only has good performance on noise attenuation, but also can maintain the characteristics of the drivetrain system in low-frequency region. The performance of other generator speed-based controllers, such as the blade pitch controller, can therefore be preserved without the retuning procedures. An experimental system having high consistency with a 2 MW wind turbine is developed and the real-time hardware-in-the-loop experiments are carried out to demonstrate the effectiveness of the damper.