基于有限元的2.5MW永磁风力发电机模态分析及刚强度研究

发布时间：2018-08-20 16:30

【摘要】：随着能源危机与环境问题的日益突出，风能因资源丰富、绿色环保等特点日益受到人们的重视。风力发电作为风能领域的主要应用，在近几十年里取得了迅猛的发展，而永磁风力发电机是风力电机的主要发展方向之一。由于永磁电机磁场的建立不需要外部励磁，因而电机的结构简单、体积较小、可靠性及效率明显提高。特别是稀土永磁材料的出现，尤其是价格的不断下降，给永磁电机提供了广泛的发展前景。本文结合三维建模软件Solidworks和有限元分析软件ANSYS对2.5MW永磁风力发电机主要部件进行有限元分析，在保证机组安全运行的前提下，为永磁风力发电机组的大型化提供了有力的支撑，对机组发电效率的提高具有积极的意义。本文将永磁风力发电机的结构分为两大部分进行研究，首先研究电机的旋转部分。根据图纸，运用ANSYS的APDL命令流建立转轴实体模型。为避免转轴因刚强度不足发生转子与定子的碰摩现象，需对转轴进行挠度分析。分析结果显示，转轴挠度满足要求。其次，运用Blocks Lanczos法分析了转轴的模态，，得出该电机转子的一阶临界转速高于工作转速，且工作转速避开了定子共振频率及转子一阶临界转速，不会发生共振。根据冲片结构的对称型，运用Solidworks软件建立冲片有限元模型，分析冲片槽不装磁钢及装磁钢两种形式下冲片刚强度状况，结果发现，冲片槽装磁钢时，圆角处应力集中较大，冲片强度不满足要求。最后，对发电机的定子部分进行机械计算。为降低永磁电机的振动和噪声，避免机组发生共振现象，分析机座不带端盖的模态。由于机座与端盖通过螺栓连接，对机座起到约束的作用，从而影响了机座的振动特性，又分析了机座带端盖的模态，两者结果表明：端盖可以改善机座的振动特性。鉴于机座在吊装、运行时受到多种载荷的作用，分析电机在整机平放、四角同时起吊、对角起吊及运行时机座的应力与形变，分析结果表明其结构达到设计要求，四角同时起吊有利于电机吊装。与传统方法相比，有限元分析方法计算简便、效率高，且利用此方法可以预测结构受力危险区域及是否会发生共振现象，可以提前做好预防处理。为机组安全运行和大型化提供了指导性建议，有利于同类型电机的研发。
[Abstract]:With the increasingly prominent energy crisis and environmental problems, wind energy has attracted more and more attention because of its rich resources and green environmental protection. As the main application of wind energy, wind power generation has made rapid development in recent decades, and permanent magnet wind turbine is one of the main development directions of wind turbine. Since the magnetic field of permanent magnet motor does not need external excitation, the structure of the motor is simple, the volume is small, and the reliability and efficiency are improved obviously. Especially, the appearance of rare earth permanent magnet materials, especially the declining price, provides a wide range of development prospects for permanent magnet motors. In this paper, the main components of 2.5MW permanent magnet wind turbine are analyzed by using the 3D modeling software Solidworks and the finite element analysis software ANSYS. On the premise of ensuring the safe operation of the unit, the paper provides a powerful support for the large-scale of the permanent magnet wind turbine. It is of positive significance to the improvement of generating efficiency. In this paper, the structure of permanent magnet wind turbine is divided into two parts. According to the drawing, the ANSYS APDL command stream is used to establish the solid model of the shaft. In order to avoid rubbing the rotor and stator due to the lack of rigid strength, the deflection of the shaft should be analyzed. The results show that the deflection of the shaft meets the requirements. Secondly, the Blocks Lanczos method is used to analyze the mode of the rotor shaft, and it is concluded that the first order critical speed of the motor rotor is higher than the working speed, and the working speed avoids the stator resonance frequency and the rotor first order critical speed, so the resonance will not occur. According to the symmetrical type of stamping plate structure, the finite element model of punch plate is established by using Solidworks software, and the rigid strength condition of punch plate under two forms of punching groove without magnetic steel and magnetic steel is analyzed. The results show that the stress concentration at the corner of the punch groove is large when it is loaded with magnetic steel. The strength of the punch does not meet the requirements. Finally, the stator part of the generator is calculated mechanically. In order to reduce the vibration and noise of the permanent magnet motor and avoid the resonance of the unit, the mode of the seat without the end cover is analyzed. Because the pedestal and the end cover are connected by bolts, the vibration characteristics of the base are affected, and the modal of the end cap is analyzed. The results show that the end cover can improve the vibration characteristics of the base. In view of the effect of a variety of loads on the machine seat when it is hoisted, the stress and deformation of the base are analyzed when the motor is laid flat, hoisted at the same time in four corners, lifted in diagonal direction and in operation. The analysis results show that the structure meets the design requirements. Hoisting at the same time is advantageous to the hoisting of motor. Compared with the traditional method, the finite element analysis method is simple and efficient, and it can be used to predict the dangerous region of the structure and whether resonance will occur, and the preventive treatment can be done well in advance. It provides guidance suggestions for the safe operation and large-scale operation of the unit, and is beneficial to the R & D of the same type motors.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM315

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