The Study Of Dynamic Characteristics And Reliability Evaluation Of Wind Turbine Transmission System Under Verying Wind Speed And Operation Control Conditions

As the energy crisis grows and the need for new energy increases, wind energy, thehigh-efficient clean energy gradually draws people’s attention, and thus wind powertechnologies have gained unprecedented development. Gear box, the core apparatus ofwind power, has the highest defect rate among all wind power devices due to its variouscomplex working conditions such as the high-altitude environment without hard support,bad weather and variable load. Therefore, it is imperative to carry out deep research ofgear box in the field of dynamics, which lays foundation for the reliability evaluation ofthe components of gear box.This dissertation, aided by National Natural Science Foundation project, studiesthe1.5MW wind generator transmission system with one-stage planetary gear anddouble-stage parallel shaft spur gear. We tend to research on its dynamic features undervariable loads in actual work with operational control and carry out a reliabilityevaluation. This study includes the following:First, a dynamic model is built with the gear box of the1.5MW wind generator asobject, and an equation is built with consideration given to the torsional deflection andtime-varying meshing stiffness of gears, transmission error, the flexibility and torsionaldeflection of bearing.Second, how to compute the variables in the dynamic equation of wind generatortransmission system is studied with close attention paid to external stimuli. An ARmodel is used to emulate wind speed. With operational control of wind generator undervariable wind speed, the wind availability ratio is computed based on the best speedcontrol and the best propeller pitch angle under various wind speeds. The time-varyinginput torque stimulus is thus gained, which will be used in later computation.Third, a program is designed to figure out the dynamic features of the gear boxincluding the frequency and vibration mode of the gear system, the co-impact oftime-varying external and internal stimuli on the gear transmission system, the matingforce of gear pairs and dynamic bearing force.Fourth, an analysis is made about the defects of gear components. The reliability ofeach gear component and that of the whole wind generator transmission system is figured out with the presumption that the gear box in this project has only two forms ofdefect, namely, endurance failure of face contact and that of root bending.