Torque vibration linear/nonlinear active disturbance rejection control of doubly-fed wind turbine transmission system

Torque fluctuation in the doubly-fed wind turbine transmission system is an important factor affecting the instability of generator power, such as rapid frequency changes and large amplitude fluctuations in wind speed, as well as nonlinear and uncertain factors in the transmission system model, have a significant impact on the torque fluctuation of the transmission system. It designs a torsional vibration linear/nonlinear active disturbance rejection switching controller considering the doubly-fed wind turbine transmission system, and conducts a stability analysis on the designed expanded state observer. The effectiveness of the proposed linear/nonlinear active disturbance rejection switching controller is verified through the joint simulation of FAST and MATLAB. Under the step wind speed, because the frequency and amplitude changes significantly when the step wind speed occurs, the linear active disturbance rejection controller shows a better control effect. However, when the wind speed tends to stabilize, the suppression effect of the nonlinear active disturbance rejection controller becomes more significant. However, when the wind speed tends to stabilize, the suppression effect of the nonlinear active disturbance rejection controller becomes more significant. When the natural frequency of the system is 0.4125 Hz, the suppression effect of the nonlinear active disturbance rejection controller on the torsion angle amplitude is significantly better than that of the linear controller, and the torsion angle amplitude decreases by approximately 71%. Under high-wind-speed turbulent conditions, due to the severe fluctuations in wind speed of the wind wheel, the linear active disturbance rejection controller demonstrates a stronger suppression capability. Overall, the designed linear/nonlinear active disturbance rejection switching controller demonstrates the characteristics of fast response speed, strong anti-interference ability and high control accuracy regardless of how the wind speed changes. Moreover, the parameter setting of the controller is simple and it has strong robustness, and it has been applied in practical engineering.