风电齿轮传动系统弹流润滑特性研究

为研究风电机组齿轮传动系统的润滑特性和动力学特性,以SQI风电机组传动系统实验平台中两级定轴齿轮箱为研究对象,综合考虑齿轮油膜刚度、齿轮啮合刚度以及轴承时变刚度等,计入轴的柔性并采用有限元法建立多自由度渐开线直齿轮动力学模型,利用Newmark 积分方法求解多源时变激励下两级齿轮传动系统的动力学特性。讨论不同工况条件对油膜刚度的影响,并研究系统润滑特性、固有频率和振型的变化规律。研究结果表明,在考虑齿轮润滑效应后,齿轮啮合刚度降低,系统动态特性变化趋于敏感,系统固有特性均有所变化,其中对第11阶影响最为突出,然而在系统共振转速附近,固有特性变化趋势有所减弱。     

6160柴油机前端传动齿轮点蚀原因及措施

本文对6160柴油机前端传动齿轮点蚀问题进行了分析,提出改进措施并取得了良好效果。通过曲轴扭振载荷计算,发现曲轴扭转振动所形成的冲击负荷远高于齿轮正常值。疲劳强度校核表明,齿轮名义工作应力超过其材料的接触疲劳极限值,从而引起齿面点蚀的发生,认为曲轴扭振过大是造成齿轮点蚀的主要原因,加装曲轴扭振减振器是解决点蚀的最为有效的方法。     

风电机组行星齿轮-滚动轴承耦合系统动态特性研究

为满足行星齿轮与滚动轴承集成设计需求,基于多体动力学理论和弹性接触理论,提出一种考虑行星齿轮与滚动轴承动态相互影响且能计算各滚动体接触载荷的行星齿轮-滚动轴承耦合系统动力学建模方法。以风电机组行星齿轮滚动轴承系统为研究对象,构建其耦合系统动力学模型,研究行星齿轮与滚动轴承间的耦合作用机理。研究发现：行星齿轮对滚动轴承动态响应影响显著,受齿轮啮合力影响滚动体接触载荷与轴承偏心轨迹呈高频波动特征,设计时应充分评估行星齿轮对滚动轴承动态响应影响。     

差动调速风电机组齿轮传动系统动态特性研究

针对差动调速齿轮传动系统的刚体动力和振动特性进行研究,考虑传动系统的实际工作状况和主要内外部参数激励,建立差动调速齿轮传动系统的非线性动力学模型和振动微分方程,在SIMULINK中搭建差动调速齿轮传动系统数值模型,仿真分析其动态特性。结果表明:相对于齿侧间隙为零,齿侧间隙不等于零则使高频振动幅值波动更明显,同时加大了对低频振动的影响,表现出明显的非线性特征,因此在差动调速齿轮传动系统的动态设计和运行过程中,应注意控制和监测齿侧间隙值。     

风电机组多级齿轮系统的故障动力学特性研究

综合考虑太阳轮支撑、时变啮合刚度和综合啮合误差等因素,建立了含太阳轮齿根裂纹故障的风电多级齿轮系统平移-扭转非线性动力学模型,研究了太阳轮齿根裂纹故障及其演化对系统动力学特性的影响。结果表明：太阳轮裂纹会影响轮齿的啮合刚度,从而影响系统的动力学响应;齿轮裂纹使得系统时域波形出现明显的周期性冲击,系统在分岔图中的运动从单周期发展为多周期;裂纹系统响应频谱中出现故障特征频率及其倍频,在啮合频率附近有大量边频成分;随着裂纹程度的加深,时域特性更加复杂,同时频谱图中故障特征频率的可识别性增强。     

风电机组变桨齿轮副侧隙计算与分析

本文针对风电机组电动变桨系统,对齿轮副侧隙进行了探索研究,考虑了影响侧隙的齿厚偏差、齿轮箱偏心和装配偏差等因素,对各种因素进行了定量计算。     

软_硬齿面齿轮的接触疲劳强度试验研究

本文介绍42CrMo调质处理与20CrMnMo渗碳淬火齿轮的接触疲劳试验的过程。其中包括试验目的、试验条件和方法、CL-100型齿轮试验机和齿轮试验件的主要参数、试验结果和数据处理、试验成果评述等。     

考虑齿轮柔性的风电机组传动系统扭振特性分析

风电机组传动系统的柔性对机组的动力特性影响较大。本文利用有限单元法,根据多柔体动力学基本理论,构建考虑风电机组齿轮箱、联轴器、发电机等传动系统柔性的分析模型;根据模态分析理论,提出一种基于矢量位移云图筛选扭振频率的方法,获取风电传动系统低频至高频的扭振模态;利用坎贝尔图以及能量比判别系统共振点。结果表明,建立多柔体动力学模型对准确评估风电机组传动系统的动态特性具有重要作用。风电机组传动系统在1.33、39.16和241.30 Hz等不同激励频率载荷作用下,分别在齿轮主轴、发电机转子和二级太阳轮轴等不同位置存在共振模态。该计算结果与工程实际高度吻合,该分析方法可为风电机组传动系统优化设计提供理论依据。     

齿面点蚀程度对齿轮动力学特性影响的分析及实验研究

齿轮啮合过程中产生的齿面疲劳破坏严重影响齿轮啮合稳定性。考虑到齿轮点蚀的演化特点,以实验齿轮为研究对象,建立了六自由度齿轮系统动力学模型,分析了不同点蚀故障程度下齿轮的时变啮合刚度;根据齿轮故障演化实验台进行相关实验,并将仿真模型与实验振动信号进行对比分析。结果表明：由点蚀故障引起的时域冲击随着点蚀沿齿廓方向的扩展逐步收敛,齿轮单齿啮合区的刚度变化对齿轮振动信号的冲击作用较强。     

发动机齿轮“点蚀”的正交试验研究

评定碳氮渗齿轮质量好坏的主要参数是渗层深度、表面碳浓度及渗层碳浓度梯度。而要获得较为准确的渗层深度,合适的表面碳浓度及平缓的碳深度梯度,除了要有正确的碳势、温度、渗碳总时间外,还要有合适的强渗时间与扩散时间之比。齿轮早期磨损点蚀的原因很多,齿轮精度、材料和热处理规范及润滑油选择不当都会造成齿轮早期磨损点蚀。研究齿轮渗碳层深度超出21.67%是否会导致齿轮点蚀,通过正交试验、工艺参数研究及金相检测分析,碳化物的分析,找出了合适的工艺参数。     

离网型风力发电机的大风限速保护研究

如果解决不好离网型风力发电机的大风限速保护问题,就会大大地降低其可靠性和安全性.文章从风轮与发电机的匹配人手,一改传统离网型风力发电机最佳功率匹配运行为峰前匹配运行,使风力发电机在大风时保持较低的风能利用系数,具有大风时的限速保护作用.     

Planetary gear load sharing of wind turbine drivetrains subjected to non‐torque loads

An analytical formulation was developed to estimate the load‐sharing and planetary loads of a three‐point suspension wind turbine drivetrain considering the effects of non‐torque loads, gravity and bearing clearance. A three‐dimensional dynamic drivetrain model that includes mesh stiffness variation, tooth modifications and gearbox housing flexibility was also established to investigate gear tooth load distribution and non‐linear tooth and bearing contact of the planetary gears. These models were validated with experimental data from the National Renewable Energy Laboratory's Gearbox Reliability Collaborative. Non‐torque loads and gravity induce fundamental excitations in the rotating carrier frame, which can increase gearbox loads and disturb load sharing. Clearance in the carrier bearings reduces the bearing stiffness significantly. This increases the amount of pitching moment transmitted from the rotor to the gear meshes and disturbs the planetary load share, thereby resulting in edge loading. Edge loading increases the likelihood of tooth pitting and planet‐bearing fatigue, leading to reduced gearbox life. Additionally, at low‐input torque, the planet‐bearing loads are often less than the minimum recommended load and thus susceptible to skidding. Copyright © 2014 John Wiley & Sons, Ltd.     

风电场风电机组的接地设计

较系统地介绍了风电场风电机组对接地电阻的要求、接地设计思路及方法,并提供实际工程中接地网布置图实例作为参考。     

特种风力发电机组塔筒防腐方案研究

高原和海洋的风能资源丰富,更能发挥大容量风力发电机组的优势,利用前景广阔。但高原和海上的自然环境恶劣,对风机承载部件——塔筒的防腐要求更为严格。针对在高原和海上运行的特种风机,分析了塔筒的腐蚀环境,研究了塔筒的防腐原理,提出了塔筒的具体防腐措施和防腐方案,为特种风机塔筒的防腐提供了参考。     

750 kW风力机组齿轮箱动力学仿真分析

风力发电机组系统运行时产生剧烈的振动,对齿轮箱的运行精度和齿轮寿命的影响非常大。针对这一情况,文章对齿轮箱进行了重新设计、建模。基于多体系统动力学方法、模态振动、冲击-接触理论,以750 kW型风机齿轮箱为研究对象,通过对齿轮箱的仿真分析,得出齿轮啮合和碰撞力以及动能随时间的变化曲线。文章还对高速齿轮轴进行了模态分析,得到弯曲模态振型图,并将高速齿轮轴、行星轮、行星架和齿轮Z1变为柔体进行应力分析,得到齿轮的应力分布图,为齿轮箱总体动力学特性分析及齿轮箱优化设计奠定基础。     

风力机叶片动态气弹变形及其对整机性能的影响

基于风力机整机刚柔耦合模型,文章提出了一种叶片动态气弹扭转变形分析的新方法。该方法采用SIMPACK和AeroDyn软件联合数值仿真对风力机在几种恶劣风况下进行动力学分析,通过对分析结果的变换处理,进而得到叶片在复杂工况下的动态气弹变形数据。采用该方法,重点分析了叶片气弹扭转变形对风力机气动功率及气弹稳定性的影响。该方法为大型风电叶片的气弹特性评价以及气弹剪裁设计提供了一种新的技术手段。     

风特性对风力发电机组输出功率的影响

为了准确研究不同类型的风速对并网风电机组输出功率的影响,建立了并网风力发电机模型和不同类型风速的模型。在不同类型风速的扰动下,对异步风电机输出功率的波动进行了仿真分析;针对引起功率振荡最严重的阵风,进行了不同频率的阵风扰动下风电机组功率振荡的比较,对阵风扰动下风电机组间的相互影响进行了仿真分析。结果表明,在相同幅值的扰动下,阵风引起的风电机组功率振荡最严重,机组功率振荡情况与阵风扰动的频率有关,单台机组在阵风扰动下产生的振荡对其他机组也会产生一定的影响。     

Effects of floating sun gear in a wind turbine's planetary gearbox with geometrical imperfections

This paper addresses the effect of gear geometrical errors in wind turbine planetary gearboxes with a floating sun gear. Numerical simulations and experiments are employed throughout the study. A National Renewable Energy Laboratory 750 kW gearbox is modelled in a multibody environment and verified using the experimental data obtained from a dynamometer test. The gear geometrical errors, which are both assembly dependent and assembly independent, are described, and planet‐pin misalignment and eccentricity are selected as the two most influential and key errors for case studies. Various load cases involving errors in the floating and non‐floating sun gear designs are simulated, and the planet‐bearing reactions, gear vibrations, gear mesh loads and bearing fatigue lives are compared. All tests and simulations are performed at the rated wind speed. For errorless gears, the non‐floating sun gear design performs better in terms of gear load variation, whereas the upwind planet bearing has more damage. In the floating sun gear scenario, the planet misalignment is neutralized by changing the sun motion pattern and the planet gear's elastic deformation. The effects of gear profile modifications are also evaluated, revealing that profile modifications such as crowning improve the effects of misalignment. Copyright © 2014 John Wiley & Sons, Ltd.     

On the definition and effect of optimum gear microgeometry modifications for the gearbox of an offshore 10-MW wind turbine

This work develops an optimization algorithm for the definition of gear microgeometry modifications (MGM) on a gearbox belonging to an offshore 10-MW wind turbine. Subsequently, the impact of the gear microgeometry on the performance of gears and bearings is quantified: First, under rated load conditions and, second, accounting for the environmental conditions to estimate the long-term damage. To fulfil this task, a high-fidelity numerical model of the drivetrain is used, which meets the design requirements of the Technical University of Denmark (DTU) 10-MW reference offshore wind turbine. The optimization achieves a uniform distribution of the contact stress along the tooth flank, shifts its maximum value to the central position, and eliminates edge contact. These enhancements increase the gear safety factors. Nevertheless, the most significant improvement concerns planetary bearings, for which optimum gear MGM achieve a homogeneous share of the load among bearings. Moreover, deviations of the microgeometry with respect to the defined optimum are also addressed. In gears, lead slope deviations are counteracted by crowning modifications to restrain the increase of the load offset. Concerning planetary bearings, slope deviations can be beneficial or detrimental depending on whether they overload downwind or upwind planetary bearings, respectively. Finally, accumulated damage to planetary bearings after 20 years of service is assessed. Before MGM, results predict a premature failure of planetary bearings, while optimum MGM extend their predicted life above 20 years by achieving a reduction of the maximum accumulated fatigue damage by a factor of 4.4.     

Sensitivity of southern California wind energy to turbine characteristics

Using output from a high‐resolution meteorological simulation, we evaluate the sensitivity of southern California wind energy generation to variations in key characteristics of current wind turbines. These characteristics include hub height, rotor diameter and rated power, and depend on turbine make and model. They shape the turbine's power curve and thus have large implications for the energy generation capacity of wind farms. For each characteristic, we find complex and substantial geographical variations in the sensitivity of energy generation. However, the sensitivity associated with each characteristic can be predicted by a single corresponding climate statistic, greatly simplifying understanding of the relationship between climate and turbine optimization for energy production. In the case of the sensitivity to rotor diameter, the change in energy output per unit change in rotor diameter at any location is directly proportional to the weighted average wind speed between the cut‐in speed and the rated speed. The sensitivity to rated power variations is likewise captured by the percent of the wind speed distribution between the turbines rated and cut‐out speeds. Finally, the sensitivity to hub height is proportional to lower atmospheric wind shear. Using a wind turbine component cost model, we also evaluate energy output increase per dollar investment in each turbine characteristic. We find that rotor diameter increases typically provide a much larger wind energy boost per dollar invested, although there are some zones where investment in the other two characteristics is competitive. Our study underscores the need for joint analysis of regional climate, turbine engineering and economic modeling to optimize wind energy production. Copyright © 2012 John Wiley & Sons, Ltd.