【作者】 李俊；

【导师】 何玉林；

【作者基本信息】 重庆大学 ， 机械工程， 2011， 博士

【摘要】 由于环境恶化、能源危机等因素,风力发电技术成为人们越来越多的关注焦点。随着风力发电机组单机容量增大,复杂程度的增加,加上海上风力发电机组的兴起,对我国在风力发电机组自主设计和制造水平上提出了更高要求。我国在风电机组总体设计与国际水平还存在较大差距,尤其在整机建模、性能仿真、载荷计算等方面尚存许多问题没有解决。本文课题来源于重庆市科技计划重点攻关项目“风力发电机组系统设计关键技术”,以大型2MW变速变桨水平轴风力发电机组系统仿真及结构优化的关键技术进行研究。由此,论文研究的主要内容及结构如下:第一章分析了风电技术的发展趋势及研究热点,提出了风力发电机组系统仿真及优化的技术需求,综述了国内外风力发电机组空气动力学、结构动力学、系统建模仿真分析以及零部件优化技术的研究现状,从而提出了风电机组整机及关键零部件仿真分析与优化设计的研究,给出了论文的主要内容和结构。第二章提出了风力机空气动力问题的一种新理论——BEM-GDW综合理论。针对在风力机气动性能计算时广泛使用的修正后的叶素动量理论(BEM),指出它仍存在无法考虑三维气动效应以及时间迟滞等缺陷。同时引出另一种理论广义动态尾流理论(GDW),指出它的优点与BEM比较它可以描述风轮盘上更一般的压力分布,它存在时间迟滞,同时风轮的诱导速率能够从一系列一阶微分方程得出,避免了使用迭代,但它的缺点是在低风速下此方法计算很不稳定。为了弥补两个理论存在的不足,将两理论综合在一起,提出了BEM-GDW综合理论,同时考虑了动态失速的影响,并将此理论在Matlab中实现。第三章结合项目,对风力发电机组整机进行模拟仿真,计算了各关键零部件载荷。详细阐述了某大型2MW变速变桨水平轴风力发电机组的建模过程,模块特征和参数定义。将各个模块的特性以及参数对模型的影响都进行了详细的研究,根据实际风场特点,按照GL规范将风力机在外部条件下进行设计载荷工况的定义。建立了风力机整机系统模型,对其进行静态和动态仿真,从而获得风电机组各个零部件的极限和疲劳载荷。这对于风力发电机组设计的各个零部件的验证以及后续的设计都起到了指导作用。同时还对海况进行初步研究,为以后的海上风力发电机组的研究奠定了基础。第四章提出了对风力发电机组在冰载条件下的研究。首次以冰载条件下的风力机为研究对象,通过数值模拟的方法,分析了冰载对风力机叶片翼型、功率以及年发电量的影响。在Matlab中,基于BEM-GDW综合理论开发了计算冰载影响因素的风力机气动性能、功率及年发电量的程序,并以某2MW变速变桨型风力机为例进行了性能仿真,将所得的功率曲线与GH Bladed软件的结果进行比较分析,验证了该数值模拟方法的正确性和实用性。第五章基于BEM-GDW综合理论,考虑实际年风速分布概率,以年发电量最大为目标,结合遗传算法搜索寻优,建立叶片优化设计程序。运用此程序,对某2MW水平轴风力机叶片进行优化设计。优化后的风力机叶片的扭角、弦长及相对厚度的分布均保持光滑并连续性过渡,便于生产和加工。同时叶片捕风能力与年发电量较之原叶片都大大提高,具有一定的理论和工程实用价值。第六章基于风力机整机的稳定性,提出了一种研究风力机塔筒结构优化的新方法。该方法以减小系统振动为目标函数,塔筒的直径和壁厚为优化参数,通过强度、变形量及质量等作为约束条件建立优化模型,利用内点惩罚函数法求解此优化问题,最后运用坎贝尔图(Campbell图)对叶片与塔筒耦合的风力机整机系统的稳定性进行分析。应用此方法对某2MW水平轴风力机塔筒结构进行优化同时用有限元软件加以验证,整机的稳定性能得到很大改善同时塔筒质量减少13%,有效地优化了原有的设计。有助于国产风力发电机组关键零部件的优化设计,为提高国产风力发电机组的设计水平和国产化打下了良好的基础,拓宽了设计思路。最后,在第七章总结了全文的主要内容和成果,并展望了未来的研究工作。更多还原

【Abstract】 Due to environment deterioration, energy crisis and other factors, wind power technology has been becoming more and more attractive to people. With the increment of single wind turbine (WT) capacity, complexity and the rise of offshore WTs, higher requirements are proposed in domestic independent wind turbine design and manufacturing. There’s still a huge gap of synthetic wind turbine design level between China and western countries, and many problems need to be solved especially on whole turbine modeling, performance simulation, load calculation, etc. This research is under the support of Chongqing Key Technologies R &D Program titled”Wind Turbine System Design Key Technology”with focus on system simulation and structure optimization of certain 2MW variable speed-pitch horizontal wind turbine. The main content and structure of the dissertation are as follows:In chapter 1,the status and hot research topics of wind power technology is analyzed. The technical requirements of WT system simulation and optimization is proposed. The research status of wind turbine system in terms of aerodynamics, structural dynamics, system modeling and simulation, and component optimization technology is reviewed. Therefore the research of wind turbine system and key components simulation and optimization is proposed. The main content and skeleton of the thesis are given as well.In chapter 2, a new theory of WT aerodynamics - BEM GDW comprehensive theory is proposed. With respect to the extensively used and revised blade element momentum theory (BEM) on WT aerodynamic performance calculation, its defects, such as no 3D aerodynamic effects,time delay, etc. are identified. Meanwhile, another theory named generalized dynamic wake theory (GDW) is solicited. GDW, compared to BEM, can describe more general pressure distribution. It does exist time delay, and the rotor induction rate can be obtained from a series of first order partial differential equation which prevents iterations. However, its calculation is unstable under low wind speeds. To remedy the deficiencies of both theories, via combination, BEM-GDW comprehensive theory is presented. The theory is fulfilled in Matlab taking account of dynamic stall.In chapter 3, the whole WT is modeled and simulated, and loads on various key components are calculated. The typical modeling process, module characteristics and parameter definition of the 2MW variable speed-pith horizontal wind turbine generator system is elaborated. Detailed research of the effects of module characteristics and parameters on the model is conducted. Based on practical wind field characteristics, design load cases of the wind turbine under real operation in accordance with GL certification are defined. The model of the whole WT system is established, and static and dynamic simulation are conducted to obtain extreme and fatigue loads of every components. It plays a guiding role on component certification and subsequent design. Also preliminary research is performed on sea condition, and lays a foundation for off shore wind turbine system design.In chapter 4, emphasis is put on ice load investigation of WTGS (wind turbine generator system). It is the first time to investigate wind turbine under ice loads. Through numerical simulation, the effects of ice load on wind turbine airfoil, power and annual power output are studied. Using Matlab, a routine which is initially used to calculate wind turbine aerodynamic performance, power and annual power output based on BEM-GDW comprehensive theory is further developed to incorporate the effects coming from ice loads. The 2MW variable speed-pitch wind turbine is used as an example to do performance simulation. The obtained power curve is compare to the results from GH Bladed, and the accuracy and practicability of the numerical simulation method is verified.In chapter 5,based on BEM-GDW comprehensive theory, considering actual annual wind distribution probability and targeting maximum annual power output, a wind turbine blade optimization routine has been developed combined with genetic algorithm technique. The routine is applied to conduct optimization design of the 2MW horizontal wind turbine blade. Smooth geometric transition along the optimized blade span with respect to twist, chord length and thickness distribution is found which is beneficial for manufacturing. Meanwhile, the energy capturing efficiency and annual power output has greatly improved based on the current optimized design, yielding evidently practical engineering application value.In chapter 6,a new method, which constructs and solves optimization model to optimize the structure of wind turbine in order to improve the stability of whole wind turbine system with coupled blade and tower, is developed. The optimization model formulation is described as the following: minimizing system vibration is the objective function, diameter and thickness of tower are decision variables, and constraints include strength, deformation and mass. Interior penalty function technique is applied to solve the optimization model, and Campbell diagram is employed to analyze the system stability. The formulation and solution method were applied to the 2MW horizontal axis wind turbine, and the stability of the whole turbine was greatly improved and tower mass was reduced by 13%, which demonstrates the proposed method not only contributes to theory research but also leads to great benefits in practice and effectively optimizes the original design, contribute to the key components of domestic wind turbine optimum design to improve the domestic wind turbine design standards, and domestic and lay a good foundation and broaden the design ideas.In Chapter 7, the important results and conclusions of the dissertation are summarized, and the prospective research work is presented.更多还原