| The research subject of the thesis stems from the project “The study of key technologies and industrialization for 7MW wind turbine gearbox and mainshaft bearing(2012BAA01B05)” in the National Science and Technology Pillars Program during the Twelfth Five-year Plan Period of China.The mechanical system of Wind turbine is much complicated and can be divided into drivetrain and support portion. The drivetrain is consist of wheel, mainshaft, gearbox and generator etc. the support portion is mainly consist of tower and cabin. In order to obtain wind energy, the wind turbine drivetrains work in the high-attitude environment which is about 100 meters high. The loads and deformations of the drivetrain are complicated due to the tower flexibility under the harsh situation of strong time-varying wind directions and loads. It has become the weak link of wind turbine. Therefore, the research on the dynamic characteristics of wind turbine drivetrain considering the flexible support has great theoretic significance and industrial application value.The main contents of this thesis are shown as follows:(1) The structure composition and transmission principle of the drivetrain with flexible support were analyzed. According to the interconnection of components, the topological graph of the drivetrain was created. The rigid-flexible coupled dynamic model of the drivetrain with flexible support was established by SIMPACK based on the multi-body system dynamic theory.(2) The inherent characteristics of the wind turbine drivetrain were analyzed. The natural frequencies and modes were calculated. Then the verification was performed by comparing the first eigenfrequency obtained from the detailed model of the drivetrain to the simulation model. The potential resonances of wind turbine drivetrain were investigated the Campbell diagram and modal energy distribution theory.(3) Considering the internal excitation of time-varying mesh stiffness and transmission errors, and the external excitation of wind load and feedback torque of generator, the dynamic responses of wind turbine drivetrain were analyzed. The dynamic responses in time domain and frequency domain for the drive train were analyzed under the given wind load condition. Also, the effects of the tower deformation on the drivetrain dynamics were investigated.(4) Experiment were carried out in the wind field, in which the vibration characteristics of the wind turbine drivetrain were monitored under the real-time test by SKF Wind system. The vibration characteristics of test points were analyzed. According to the VDI3834 standard criticism, the vibration properties of the drivetrain were analyzed. The experimental results also compare well with the theoretical dynamic results. |
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