A Nonlinear Drivetrain Torsional Oscillation Damper for WTGs: Robust Rejection of Large Disturbances with Balanced Noise Immunity

Drivetrain torsional oscillations in wind turbine generators (WTGs) challenge power system reliability and stability due to nonlinearities and uncertainties, especially under large disturbances, while measurement noise further degrades damper performance. This paper develops a nonlinear drivetrain torsional oscillation damper (DTOD) within an active disturbance rejection control (ADRC) framework. To adapt to its standard form, the nonlinear drivetrain dynamics of grid-connected WTG are exactly transformed into a second-order Brunovsky canonical form using differential homeomorphism coordinate transformation. DTOD parameters, including those of the extended state observer (ESO) and nonlinear state error feedback (NLSEF), are Pareto-optimally tuned through normalized multi-objective frequency-domain optimization, enhancing the robust rejection of large disturbance while balancing the trade-off with noise immunity. The fully decentralized DTOD relies only on local measurements, supporting scalable deployment across large wind farms. Simulation results under various large disturbance scenarios in grid-connected single and multiple wind farms validate the effectiveness, advantages, robustness, and scalability of the proposed nonlinear WTG DTOD.