| Planetary gear system for wind turbine gearbox is a key mechanical system for energy conversion and reliability in drivetrain for wind turbine. However, due to the adverse and tough working condition of wind turbine and complicated structural characteristics, if the error exists or occur during design, manufacturing and assembling process, the occurrence of reliability problem in planetary gear system is easier than parallel gear system. Thus, Analysis and information regarding the relationship between what kind of error and mechanic characteristics or reliability is significant to establish the plan to avoid or solve the problem are error factor makes and increase reliability of wind turbine gearbox. Among lots of error type, manufacturing error is the error we cannot totally avoid and prevent and also is frequently occurred. Especially, so far as it is known, pin-hole position error of carrier is the most influential manufacturing error type against balanced power flow and load sharing characteristic. Through the change of power flow and load sharing characteristics, it cause serious reduction of lifetime and abnormal failure. Hence, research how pin-hole error influence to power flow and fatigue characteristic of planetary gear system is the basis research for high reliability planetary gears for wind turbine.This research employs the planetary gear model for 1.5MW wind turbine gearbox as main research model and conduct a study on the influence of pin-hole positional error to planet load sharing and fatigue life of key component of wind turbine planetary gear system. First of all, the power flow model for planetary gear is built for studying of power flow for every component in planetary gear and analysis of influence of pin-hole position error and errors regarding wind turbine working condition to power flow and load sharing. The result of this analysis will be a basis for analysis for lifetime and failure characteristics.Second is to build dynamic simulation model for planetary gear. In this chapter, based on previous dynamic studies for planetary gear system, rigid body dynamic simulation model for planetary gear will be built using MSC.ADAMS. This is a virtual platform to analyze how pin-hole position error influence to load sharing for planetary gear and obtain specific data regarding dynamics such as mesh force or frequency to analyze lifetime and failure characteristics. Load sharing factor is the most common way to estimate load sharing for planetary gear. Thus, the analysis of influence of pin-hole error to load sharing will be conducted using load sharing factor calculated by simulation results.Based on the results of dynamic simulation, lifetime analysis will be conducted. For gear tooth and bearing lifetime analysis, lifetime calculation method in ISO will be applied. For another part, FEM will be applied using ABAQUS. Through FEM model, we can get stress and strain result in the condition we add and we also can get strain-life curve for different hardness material based on Roessle and Fatemi method. Through this model, we can obtain the lifetime and fatigue position result of planetary gear system in the condition error exists.Finally, the conclusion of this research will be verified using real case study which are two of 1.5MW wind turbine gearbox failure accidents. More specifically, we will undergo investigation of related data, material analysis and macroscopic examination and based on the results of these analysis, the conclusion of this research can be verified.This research will be able to offer the guideline to prevent abnormal failure and reduction of lifetime for planetary gear of wind turbine and support to improve the reliability of wind turbine gearbox. |
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