Dynamic Characteristics Research Of Megawatt Level Wind Turbine Drive Train

The research subject of the thesis stems from the project “The study of keytechnologies of industrialization for7MW wind turbine gearbox and spindle bearing” inthe National Science and Technology Pillar Program during the Twelfth Five-year PlanPeriod of China.The wind turbine drive train is a complex elastic system, mainly consisting of blade,main shaft, gearbox, flexible coupling and generator, etc. Under the comprehensiveaction of external excitation,time-varying wind load and feedback load, and the internalexcitation inside the gearbox, the system shows the characters of coupling effects andhigh nonlinear behaviors. As the wind turbine has a wide working speed range andexcitation frequency band, it is easy for the system to occur resonance. Therefore, theresearch on the dynamic characteristics of wind turbine drive train has great practicalvalues and industrial significance.The main contents of this thesis are shown as follows:①Based on one certain megawatt level wind turbine, the formation andtransmission principle of the drive train is analyzed. Treating the blade, hub, main shaftand gearbox as the elastic body, based on the flexible multi-body system dynamic theory,the dynamic model of the gear driving system is built by the method of FE dynamicsubstructure reduction.②The inherent characteristics of wind turbine drive train is analyzed. On thestrength of Campbell diagram, modal energy distribution and order analysis, theresearch on potential resonance is conducted.③Considering the external excitation, including wind load, driving torque withtower shadow effect and feedback load of generator, and the internal excitation,including time-varying meshing stiffness and transmission error, comprehensively, thedynamic response of the wind turbine drive train is researched, getting the vibration andstructural noise of the drive chain.④The testing system is built and the experimental study on the torsional vibrationcharacteristics and structural noise in the wind farm are conducted, validating thesimulation result.