Research On Dynamic Torsional Load Control Of Double-fed Wind Turbine Drive System

Double-fed wind turbine is widely used in the market currently. Due to the capacity ofwind turbine becomes larger and larger, and its development tendency is from land toocean. Load problem has been the importance in wind turbine designing and operating.The high failure rate of drive system impedes the rapid development of double-fed windturbine. Therefore, dynamic torsional load control based on kalman state estimation andfederated control of pitch and torque has been proposed respectively selecting double-fedwind turbine nonlinear and linear model as the object. Active control approach forreducing dynamic torsional load of drive system has been researched.The forming reason of torsional load of drive system has been analyzed. Then thedynamic torsional load controller based kalman state estimation has been designedselecting double-fed wind turbine nonlinear model as the object. Kalman filter has beenused to estimate the state variable needed in controller. Finally the controller reducesdrive-train torque ripple by reducing the equivalent speed difference on the shaft, andimplements the dynamic torsional load control. The system has been simulated to verifythe effectiveness by software MATLAB.According to the modern control theory, the federated control of pitch and torque hasbeen proposed selecting double-fed wind turbine linear model as the object. Consideringthe disturbance of wind speed, pitch has been controlled by linear quadratic regulator basedon disturbance accommodating to implement the minimization controller action anddrive-train torque ripple. The torque controller adopts pole-assignment to increase drivesystem damping. Finally the federated control of pitch and torque has been verified bysoftware MATLAB and FAST. Simulation result illustrated that drive system dynamictorsional load can be reduced to improve reliability of wind turbine and extend service lifeof critical components by active control method.