Stability And Hopf Bifurcation Analysis In Wind Power And Rotor System With Random Parameter Excitation

With the development of our human society,Electric energy is being needed everywhere.Nowadays the importance of energy sources are coal and petroleum in the world.which support today's electrification and the age of information.However,as human is wanton mining for fossil fuels and coal energy,gradually tradition energies are exhausted.Meanwhile the large-scale use of tradition energies caused serious destruction of ecological environment.What's more,the stress of oil source scarcity and deterioration of urban environment become more and more severe.so,the development of renewable green energy has become the inevitable direction of the future national energy strategy,such as solar energy,wind power,etc.Among them,one of the most extensive researches is wind energy and it telechnongy has tended to mature.In 2006,the renewable energy law was promulgated by China.And then,Chinese wind power industry has made a qualitative development.Wind power project is renewable energy support technology which is key to supported,it is of great significance to the economic development at home and broad.It ensure that the wind power generation system has a stable power output,which is the main task in the research of wind power generation.The paper is doing research on the wind-driven generator which is the capital equipment utilized to transfer wind energy to electricity power.Because of the complex structure of rotor system and material heterogeneity,as well as the impact of random wind forces,which can lead to uncertainties of the rotor system.In this paper,the dynamic behavior of wind turbine rotor system is studied by using nonlinear stochastic dynamics theory,the main contents are as follows:1.It present development of the system investigated about rotor bearing system,then the basic theory of stochastic nonlinear dynamics is described.Include stochastic averaging methods,largest Lyapunov exponent method and boundary theory.2.The stability and Hopf bifurcation of a wind power generation system with stochastic wind disturbance are studied,which the internal factors of the system and the influence of external random wind force are replaced by Gauss white noise.The quasi Hamilton system converges to a one-dimensional Ito stochastic differential equation by stochastic averaging methods,and the local stability of the system can be obtained by the largest Lyapunov exponent.Finally,the Hopf bifurcation of the system is simulated by solution of FPK equation.3.The stability and Hopf bifurcation of a high-speed rotor bearing system with stochastic excitation are studied,The quasi Hamilton system converges to a one-dimensional Ito stochastic differential equation by stochastic averaging methods.After analyzing the local stability by using the largest Lyapunov exponent,the global stability of the system is analyzed by using the singular boundary theory of Ito stochastic differential equation.The process of the system from stable to Hopf bifurcation is simulated by the stationary probability density function and the joint probability density function.4.The stochastic dynamic behavior of a four-dimensional rotor system is studied.For the four-dimensional stochastic nonlinear systems,we can also use the Quasi Integrable Hamilton system theory,and the Hamilton function converges wakely in probability to a one-dimensional Ito stochastic process.However,in order to avoid the calculation of multiple integrals,the polar coordinate transformation is introduced.Then the local stability and global stability are analyzed,and the Hopf bifurcation of the system is simulated.