| The main drive train of wind turbine is not only the transmission channel of energy,but also the transmission path of the unit load.The main drive train of double-fed turbine is in extreme climatic conditions and harsh working environment for a long time,with a wide range of working speed,wide excitation band,and the excitation frequency is easy to resonate with the inherent frequency of the system during the change of drive train speed;and the time-varying wind load often causes the flexible tower to oscillate,and the inertia force of the drive train components and the pneumatic load of the system are coupled with each other.Inertia force and system pneumatic load coupled with each other,so that the parts of the force fluctuations increase,resulting in its failure rate increased.One of the reasons for the early occurrence of abnormal operating conditions of the main drive train is that the real-time dynamic load of the system and its transmission characteristics are unclear,and the dynamics behavior of multiple conditions is unknown.Therefore,the study of the real-time dynamic load of the main drive train of wind turbine and the mastering of the system time-service load law and its dynamics characteristics are the primary key issues for the safe and reliable service of wind turbine.This paper takes a WT2000D110H80 double-fed wind turbine with a single capacity of 2MW installed in a wind farm in northwest China as the research object,analyzes the dynamic coupling mechanism between hub,main shaft,main bearing and gearbox,establishes the main shaft as a flexible body under service environment,and establishes a multi-conditions wind turbine main drive train considering the non-linear factors such as tower oscillation and time-varying meshing stiffness.The dynamics model of hubspindle-main bearing-gearbox is established,and its dynamic characteristics and load transfer characteristics are analyzed.The SCADA database is mined for the characteristic parameters related to the main drive train operating conditions,and the dynamics of the actual wind turbine main drive train is compared with the dynamics of the wind turbine main drive train based on mathematical modeling,and the proposed wind turbine main drive train dynamics model is revised based on this.The details of the study are as follows:The structure of the wind turbine main drive train is introduced,its structural characteristics are analyzed,and the structure of the 2MWWT2000D110H80 double-fed wind turbine gearbox is highlighted,and the specific known parameters of the wind turbine main drive train are given to provide the basis for the subsequent dynamics study;in addition,the time-varying wind speed conditions,time-varying hub speed conditions,and the time-varying input torque at the hub end based on the SCADA real-time acquisition are analyzed to provide input data for the analysis of the dynamics behavior in Chapter 3.In addition,the time-varying input torque input at the hub end is analyzed to provide input data for the dynamics behavior analysis in Chapter 3.The centralized mass parameter method is used to establish the dynamics model of the wind turbine hub-spindle-main bearing-gearbox;the degrees of freedom and corresponding generalized coordinates are determined,and the kinetic energy and potential energy of the system expressed in generalized coordinates are calculated;the second type of Lagrangian equations are used to establish the dynamics equations of each subsystem of the wind turbine main drive system,and the overall differential equations of motion of the wind turbine main drive system are established according to the coupling mechanism and connection boundary conditions between each subsystem in the main drive system.The method of solving the time-varying mesh stiffness of planetary wheel-sun wheel and the time-varying mesh stiffness of fixed-axis gear system,as well as their corresponding damping magnitudes,are provided.The fourth-order Lundgren-Kutta method is used to find the corresponding torsional displacement,torsional vibration acceleration and vibration velocity response in each direction for the differential equations of motion of the objects obtained in the previous chapter,and the dynamic response characteristics of the objects are analyzed.The SCADA data collection and data processing of a wind farm in northwest China are introduced,and the characteristic parameters related to the main drive train operation status in the SCADA database are mined to analyze its dynamic characteristics,compare the dynamic behavior of the actual wind turbine main drive train with the dynamic behavior of the wind turbine main drive train based on mathematical modeling,and modify the proposed wind turbine main drive train dynamic model based on this,and obtain The accurate mathematical model and its dynamic response characteristics are obtained. |
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