【作者】 黄学君；

【导师】 邱家俊；

【作者基本信息】 天津大学 ， 工程力学， 2004， 硕士

【摘要】 随着发电机组向大型化发展，特别是其高电压、大电流的进一步提高，势必导致发电机磁场强度和电场强度的提高，发电机定子壳体的磁应力张量、电应力张量也将增加，发电机中的磁固耦合作用越来越不容忽视，对大型水轮发电机组定子系统的磁固耦合动力学进行深入的研究变得越来越重要。本文以ABB公司产的777.8MW水轮发电机组为实际工程背景，对大型水轮发电机组定子系统三相对称稳态运行状态下的磁固耦合振动进行了系统的研究。文中通过建立定子系统的双壳系统模型，结合圆柱壳的粱函数组合法，来分析双壳系统的固有频率和振型，并建立了定子系统的磁固耦合动力学方程，用多尺度法分析了定子系统的磁固耦合非线性振动。主要工作概括为以下几个部分：一 建立水轮发电机组定子系统的双壳模型，把定子系统简化为弹性联系的两个同心圆柱壳，连接弹簧的刚度冷态时视为零，热态时取为无穷大。二 计算了三相对称稳态运行状态下考虑定子铁心径向振动位移与气隙磁场的相互耦合时，作用于水轮发电机定子铁心内圆表面的电磁力。计算电磁力时，考虑了定子铁心的径向振动位移对电磁力的影响。三 利用圆柱壳的梁函数组合法给出了水轮发电机组定子系统双壳模型的固有频率和振型的表达式，得到了水轮发电机组定子系统双壳模型的固有频率。四 建立系统振动的微分方程，并利用多尺度法分析了水轮发电机组定子系统双壳模型由电磁激发的强迫共振的非线性动力学特性。五 分析了电磁刚度对水轮发电机定子系统固有频率的影响，电磁刚度对低阶固有频率影响较大，因此电磁刚度对低阶固有频率的影响是不能忽视的。更多还原

【Abstract】 As the turbogenerator are developing towards the large scale, especially with it’s voltage and electric current enhancing even more than before, inevitable results are that electromagnetism field intensity and electromagnetism stress of turbogenerator are increased, and that the magnetism and solid coupling in the turbogenerator become more and more apparent. Hence it becomes more important to study the magnetism and solid coupling dynamics of turbogenerator stator system. The engineering background of the thesis is based on the 777.8MW water turbogenerator produced by ABB Corporations. Magnetism and soldid coupling vibration of water turbogenerator stator system is studied systematically when three-phase symmetric steady state. Through establishing a double-shell model of the water turbogenerator stator system, and the natural characteristic of the double-shell stator system is derived by means of the combination method of beam function. Magnetism and soldid coupling dynamic equation of the stator system is proposed. By using the method of multiple scales for nonlinear oscillation, nonlinear oscillation of magnetism and soldid coupling of stator system is investigated.The main work can be outlined as follows:(1) To establish the double-shell from the water turbogenerator stator system, the water turbogenerator stator system is simplified as double cylinder shells which contact with springs each other. The spring stiffness of cold state is considered as zero,and the spring stiffness of hot state is regarded as infinity.(2) In three-phase symmetric steady state the electromagnetic forces acting on the inner surface of the water turbogenerator stator core are obtained in consideration of the radial vibration displacements with the magnetic field in air gap coupling of the stator core. While calculating the electromagnetic forces, the effect of the radial vibration displacements of stator core on the electromagnetic forces is taked into account.(3) By means of the combination method of beam function, the analytic expressions formula of the inherent vibration modes of the stator system double-shell model are derived, and the inherent frequency of the stator system double-shell model is obtained.(4) The stator system vibration differential equation is established. Through using the method of multiple scales, the nonlinear dynamic characteristics of the forced resonances of the stator system double-shell model excited by electromagnetic forces are analyzed.(5) The effect of electromagnetism stiffness upon the inherent frequency of the stator system is analysed.更多还原