Study On MW Wind Turbine System And Its Key Components Dynamic Mechanical Analysis

With the rapid development of wind power generation in China, the large wind turbine system independent design level and manufacturing capacity will face new challenges. Now, the large wind turbine system design,the independent research of the MW Wind Turbine system and its key components compared With the international wind power technology is still have a large gap. There are many problems to be solved in the whole system modeling, dynamic analysis and dynamic characteristics of the research. There are the two research hotspot at present, one is how properly to establish the dynamic simulation models of the large-scale wind turbine systems, and another one is how properly to simulation analysis of the performance of the wind turbine and motion. It has attracted many researchers attention.In this thesis, the Optimization of the MW Wind Turbine system and its Key Components dynamic mechanical analysis research was developed by support of the National Natural Science Fund. We using Kane method established the wind turbine multibody dynamics model.The controllability and observability of the model are analyzed in this paper according to the different state variables. We using Euler-Bernoulli beam element analysis the blade inherent characteristics, and the blade dynamic characteristics has been analysed.The MW Wind Turbine rigid gear subsystem model is established by using lumped parameter method and the elastic ring gear subsystem is established by using FEA method. The natural frequency and vibration modes were determined, and the distribution rules of the natural frequency for this coupled system were described. Finally, we conducted research on the dynamic properties of the tower stell-concrete structure under the complex environment and working condition. Each chapter mutually independent and correlated which has already formed one more complete system based on the MW Wind Turbine system and its Key Components dynamic mechanical analysis research. The main researches of the thesis are as follows:The first chapter introduces the situation of wind power generation at home and abroad in recent years. This chapter describes the research methods of the wind turbine in aerodynamics, machine dynamics modeling and simulation analysis. The research and application of new technologies such as Blades, tower, transmission system are reviewed. Therefore, this chapter presents a topic which is the MW wind turbine system and its key components dynamic mechanical analysis.The second chapter using Kane method established the wind turbine multibody dynamics model. Through select accurate operation points and calculate the cycle state matrix, put forward the nonlinear aerodynamic wind turbine model linearization method. A simplified model of MW wind turbine system is established and simulated by computer. According to the different state variables especially analysis the controllability and observability of 3 DOF and 5 DOF.The third chapter introduces the method of the large-scale wind generator blade design. It could generate the requirements of turbine blade 3D model based on the key parameter such as: leaf length, chord length and thickness-chord ratio. We using Euler-Bernoulli beam element analysis the blade inherent characteristics. Get the inherent frequency of leaf tissue structure. Summarizes at last, the distribution regularity of blade vibration mode was summed up. We use the blade aerodynamic model to calculate the blade aerodynamic load under the three-dimensional turbulent wind field. Study on the four working condition, normal working condition of power generation; accompanied by extreme wind conditions; failure condition; limit the storm condition; the static and dynamic characteristics of the blade subjected to different loads are analyzed.The fourth chapter describes a novel modelling method for rigid-flexible coupled planetary gear transmission system, which consists of rigid gear subsystem and elastic ring gear subsystem. The rigid gear subsystem model is established by using lumped parameter method and the elastic ring gear subsystem is established by using FEA method. According to compatible state of deformation between mesh force and ring gear deformation, the natural frequency and vibration modes were determined, and the distribution rules of the natural frequency for this coupled system were described. Based on the vibration characteristics of the system, the vibration modes were classified into six different modes. The effects of system rigidity to the sensitivity of different orders of natural frequency were calculated, which can serve as the bases for planetary transmission system vibration suppression. The influences of torsional stiffness of sun gear and the mesh stiffness between sun gear and planetary gears to the torsional vibration of the system were analyzed. The gear rim thickness on the system natural frequency distribution, subsystem coupling order time and the influence of the vibration mode were discussed. We find the natural frequency appear in the position of the gear subsystem torsional vibration frequency, but the ring gear vibration mode is gradually by the high-order section diameter reduced gradually with the increasing of the thickness of the ring gear,System first order mode will change section by node diameter vibration model for gear ring rigid vibration mode.The fifth chapter describes the wind turbine steel-concrete composite tower as the research object. The tower structure finite element analysis model was established, and shell elements and beam elements are used for meshing the frame, which can simplify the modeling. The intensity and stiffness of the tower structure are analyzed. Moreover, we calculated the flexible distribution and dangerous section position of the wind turbine steel-concrete composite tower. A practical improved mode superposition algorithm is proposed in this paper, we calculated the steady-state dynamic response tower structure and the wind tower structure dynamic response process. Analyzes the dynamic characteristics of tower structure in different operating conditions are described, such as turbulent wind, extreme gusts, start-up conditions, normal shut down conditions.Summarize the thesis, introduced by the major research thesis, and points out the shortcomings and future prospects on the MW Wind Turbine system and its Key Components dynamic mechanical analysis.