Dynamic active torque coordination strategy for torsional vibration suppression in wind turbines during grid fault recovery

When the grid fault occurs, wind turbines are required to possess fault ride-through (FRT) capability and rapidly restore active power after fault clearance. However, this process often leads to sharp fluctuations in active power and electromagnetic torque, which inevitably induces torsional vibrations and increased fatigue loads in the drive-train. In this paper, the torsional vibration characteristics of the drive-train system in a doubly-fed induction generator (DFIG) under grid fault conditions are investigated. A co-simulation model is established to analyze the load response during Grid Fault Recovery. Subsequently, two typical load mitigation strategies are introduced: one based on torque compensation and the other on active power recovery. To further enhance torsional vibration suppression, a coordinated mitigation strategy that integrates active power recovery with torque compensation is proposed, in which active disturbance rejection control (ADRC) is incorporated into the torque compensation strategy. The effectiveness of the proposed method is validated using a co-simulation platform that integrates GH-Bladed and MATLAB/Simulink. The results demonstrate that the proposed approach significantly suppresses torsional vibrations in the drive-train after fault clearance.