| The increasingly serious environmental pollution and the lack of renewable energy, make wind energy with a new role in the list of available new energy. At the same time, because of its large reserves, safe and reliable as well as clean and renewable, and many other advantages, it has become the backbone of the new power supply. However, due to the particularity of the work environment, the maintenance is difficult and costly, so the requirements of service life and reliability of each component are very high. Gear transmission system as the key part of wind turbine,its performance directly affects the safety and reliability of the whole machine.Therefore, it is necessary to do research on its dynamic characteristics.In this paper, 1.5MW wind turbine gear transmission system is studied. The mathematical models of random wind speed, gear transmission and gear fault states are established to analyze the dynamic characteristics of gear transmission under different gear fault condition, and find out the laws. All these above provided certain theoretical basis for wind turbine fault detection and early warning. Finally, the planetary gear system is analyzed by finite element method. The specific contents and conclusions are as follows:(1) Based on the characteristics of wind resources, a random wind speed model is established by using harmonic superposition method. The torque time-distance graph of wind wheel is also obtained according to the random wind speed. And the torque provides external incentives for the dynamic analysis of wind turbine gear transmission system.(2) Taking into account the influence of time-varying meshing stiffness of gear and bearing stiffness, the dynamic differential equation of gear transmission system is established by using concentrated mass method. The equation model fully considers the force of each component, and describes the actual working condition of the system more accurately, which provides the foundation for the dynamic response analysis of the system with gear fault.(3) According to characteristics of different gear faults, the gear time-varying meshing stiffness of gear transmission system is established. The dynamic response of the gear transmission system under different faults is obtained, and the influence of the gear transmission system on the gear transmission system is studied and analyzed. Results show that the system dynamic response amplitude under different forms of gear fault produce different degrees of fluctuations, the amplitudefluctuation that caused by tooth root crack fault is more obviously and the meshing force amplitude fluctuation showing asymmetry.(4) The planetary gear which is the key component of the gear transmission system is analyzed by using FEM. First of all, the modal analysis is carried out, and the natural frequencies and modes are obtained, which provides reference for avoiding harmful vibration. Second, its transient dynamics under random wind load is simulated and analyzed, the maximum stress, strain and time-distance graph are obtained. Results show that the changing trend of stress and strain of planetary gear is consistent with out incentives, which provide a reference for the study of the changes of stress and strain. |
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