Study And Simulation Analysis Of The Drive Train Dynamics Of Direct-Drive Wind Turbine

The large variable speed constant frequency wind turbine now is main current in wind turbine market, with the wind turbine becoming large, the request that the mass of a wind turbine becomes lighter, the structure becomes more flexible, the control becomes more precise and operation becomes more reliable. Because of the blade longer and the tower higher, the dynamic characteristic of wind turbines behave more distinctive, and the phenomena of vibration and unstable operation behave easy, even, some components of wind turbine have been failure easily. And the dynamic problem of drive train of wind turbine is one of the most complicated problems.The direct-drive variable speed constant frequency wind turbine adopts multi-pole generator and direct connection with rotor to drive generator and have no gear box, so the structure is simple and the rate of fault is low and the maintenance is convenient, but the dynamic characteristic of the drive train has charged, the turbines can vibrate easily on some condition. The investigation object of paper is the dynamic analysis of the drive train of one certain direct-drive variable constant frequency wind turbine on the input from wind. The current state of investigation of the drive train dynamic analysis of direct-drive wind turbine had been summed up, then turbulence wind modeling and gust modeling had been set up, and the blade free dynamic analysis had been studied deeply, and the drive train modeling, all these work were encircled the issue of dynamics response of one certain direct-drive wind turbine. After an extensive literature survey, the following work had been accomplished.Firstly, based on the application of the principle of inverse discrete fourier transform to calculate the wind of one point of space, the three dimension turbulence wind have been simulated on the condition of the 70m high, the 11m/s average velocity and the 0.18 turbulence intensity. Secondly, the blade had been modeled, the blade free vibration had been analyzed, and the natural frequency and modal of the flapwise and edgewise of the blade had been gained. The drive train model had been built, and the control model of speed-torque for generator also had been built.Finally, different wind models had been loaded on the modal of direct-drive wind turbine which had been built in FAST code, and the dynamic response of drive train of direct-drive wind turbine under the different wind model had been analyzed and the pitch movement effect on the drive train of direct-drive wind turbine also had been analyzed. The time response course of drive train components of direct-drive wind turbines had been obtained. And the conclusion had been gained that the length is smaller, the width of the frequency region become bigger which activize the blade vibration, and that the shaft amplitude was higher near to the first two natural frequency of edgewise of blade.The issue of direct-drive wind turbine dynamic response has gone farther under the work of this paper. As the result, it possesses significance on the vibration analysis of direct-drive wind turbines, the control strategies and the design of controller for direct-drive wind turbine.