The Dynamic Analysis Of Planetary Gear System In Fault Of Megawatts Wind Generator

With the progress of human beings and the development of science and technology,people’s demand for energy is increasing.The consumption of fossil energy such as coal and oil,together with the environmental pollution in the process of use,urgently needs us to seek development of new energy.Compared with coal,oil,natural gas and other traditional energy,wind energy,as a kind of renewable energy with rich reserves,clean and pollution-free,has attracted more and more attention.Wind power generation has also become an important part of China’s national grid.As an important part of wind generator,wind power gear transmission system is also one of the part with high incidence of failure in wind power system.Therefore,it is of great significance to study the fault dynamics of gear transmission system of wind generator.Taking the planetary gear system in a 1.5WM wind turbine as the research object,the dynamic behavior of the planetary gear system in the healthy state,single fault state and multiple fault state is studied,which provides a theoretical basis for early fault monitoring and diagnosis of the planetary gear transmission system in the wind turbine.1.Taking the planetary gear system in a 1.5WM wind turbine as the research object,the dynamic analysis model of the system is established by using the centralized parameter method.Based on Newton’s equations of motion,the differential equations of free torsional and translational dynamics of the system are derived by considering the effects of damping,time-varying mesh stiffness,variable load input and phase angle of the planetary gear.In addition,the internal and external excitation of the system are calculated and simulated.2.Firstly,based on the energy method,the formula for calculating the meshing stiffness of the meshing gear pair is derived.Then,taking the sun gear and the planetary gear as the study subjects,the meshing stiffness of the sun gear and the planetary gear in the state of uniform wear is calculated,and the influence of the wear amount on the meshing stiffness is analyzed.Finally,the influence of wear on the dynamic response of the system is studied from time domain and frequency domain.3.The formula for calculating the meshing stiffness of the meshing gear is derived.The meshing stiffness between the sun gear and the planetary gear is calculated.The dynamic response of each part of the system is analyzed when the broken tooth fault occurs.By analyzing the characteristic parameters of the vibration signal,the influence degree of the broken tooth fault on the dynamic response of each component of the system is studied.4.The formulas for calculating the meshing stiffness of gear with wear-crack coupling fault and wear-break coupling fault are derived respectively.The dynamic characteristics of the system under wear-crack coupling fault and wear-break coupling fault are studied respectively,and the effect of crack propagation on the dynamic response of the system under wear state is studied.At the same time,the specific differences between the effects of wear-break tooth failure and single tooth break failure on the dynamic response of the system are analyzed.