Robust Nonlinear Controller for Wind Turbine Generator Drivetrain Torsional Oscillation under Large Disturbances

This paper proposes a robust nonlinear controller to damp the drivetrain torsional oscillations (DTTOs) of wind turbine generators (WTGs) following large disturbances. The key idea is to integrate a nonlinear sliding-mode control (SMC) with an extended state observer. The former allows transforming the WTG nonlinear model into a simple first-order nonlinear system via the sliding-mode function, whereas the latter can accurately estimate the nonlinear part of the transformed system and effectively compensate the large disturbances. Simulation results show that, under various conditions, the proposed controller achieves significantly enhanced robustness and performance over the linearization-based controller and conventional SMC.