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1.
水轮发电机转子偏心引起的非线性电磁振动   总被引:5,自引:0,他引:5  
由于机械和电磁相互耦合,水轮发电机的电磁振动具有强非线性特征。根据不平衡磁拉力与转子偏心的非线性函数关系,通过简化的各向同性的单圆盘转子系统,建立了水轮发电机转子电磁振动的非线性系统。利用非线性振动理论的多尺度方法,从理论上分析了该系统强迫振动的稳态响应,进而研究了水轮发电机转子偏心引起的电磁振动。研究发现不平衡磁拉力使系统的涡动频率下降,使运动的中心发生变化;并且会引起两倍转频的振动。最后用模型转子仿真试验的结果验证了这些理论分析的结论。  相似文献   

2.
大型汽轮发电机组短路时轴系扭振动力响应计算与分析   总被引:2,自引:0,他引:2  
江红  潘勇 《应用力学学报》1996,13(2):114-118
大型汽轮发电机组在短路时的轴系扭振动力响应,对于机组的安全可靠运行甚为关键。本文以国产某200MW机组为例,建立了轴系的连续质量计算模型,利用传递矩阵法求得其扭振固有频率及主振型,用振型查加法计算轴系在两相短路情况下的动力响应,计算中考虑了叶片叶轮系统与轴系扭振的耦合作用。本文对计算结果进行了分析,讨论了该机组的轴系扭振安全性,为机组的安全运行提供了理论依据。  相似文献   

3.
水轮发电机定子系统电磁激发参强联合共振   总被引:2,自引:0,他引:2  
分析了水轮发电机定子系统的参、强联合共振,求得了稳态响应的分岔方程,进行了奇异性分析,揭示了一些新的规律和现象。给出了物理参数平面上的转迁集与分岔图,便于工程实际参考使用本文的分析结果。  相似文献   

4.
电动机-弹性连杆机构系统的动态方程及其响应   总被引:2,自引:0,他引:2  
针对三相交流电机转子振动偏心时不均匀气隙的气隙磁场,分析其实际运行状态的机电耦合关系.建立以电机横振、扭振为节点位移的电机单元,应用有限单元法建立含电机电磁参数和弹性连杆机构结构参数的系统动态方程,并根据该方程对系统的动态响应进行仿真计算和分析,且通过实验进行验征,表明所建方程较好地反映丁系统动态性能与其电磁参数、结构参数之间的关系.  相似文献   

5.
建立了考虑弯扭耦合作用时 ,大型气轮发电机组转子轴系与电网耦合次同步谐振 ( SSR)的 1 9维非线性模型。运用数值方法 ,确定系统平衡位置稳定性的转变点 ,着重分析了在不同偏心条件下 ,弯曲振动与扭转振动之间的相互影响 ,同时给出了轴系弯曲刚度对系统稳定性的影响 ,证明在正常情况下 ,由偏心引起的弯扭耦合作用是非常弱的 ,可以不予考虑  相似文献   

6.
杨志安  邱家俊 《实验力学》1998,13(3):410-415
进行了发电机组轴系电磁激发横、扭耦合振动的实验,得到了当扭振满足强迫共振时电磁激发轴系横、扭耦合振动的规律,验证了文献[1]的理论结果。  相似文献   

7.
本文研究在周期激振力作用下转子轴承系统电磁阻尼器的位移反馈振动控制。首先给出受电磁阻尼器控制的一般线性多自由度转子轴承系统的振动方程,控制力和电磁阻尼器结构参数,控制电流等之间的关系式,然后提出在保证系统稳定的前提下,通过位移反馈控制其电流位移增益矩阵应满足的条件;其次以单盘对称转子轴承系统为例,求出转子系统受电磁阻器控制的幅频响应和相频响应;最后给出算例,打印出电磁阻尼器的静态电流,电流位移增益  相似文献   

8.
多维磁浮柔性转子控制系统分岔与控制器设计   总被引:1,自引:1,他引:0  
姚宏  徐健学 《力学学报》2001,33(1):121-127
讨论了多维悬浮柔性转子控制系统局部及全局分岔问题,首先建立了该复杂系统动力学模型,应用中心流形和求规范形综合方法,得到此系统非半简双零特征值问题的规范形及其普适开折,并进一步讨论了此控制系统的分岔 行为(余维二分岔)及稳定性;给出了为实现稳定控制,控制器参数、转子系统结构参数的相互关系及稳定控制域,即给出分岔 参数条件、分岔曲线、转迁集,最后,给出此柔性转子控制系统的数值仿真结果。  相似文献   

9.
水力机组因事故进入紧急停机过程时,机组转速急剧上升然后逐渐减速,轴系振动幅度产生较大变化,可能诱发轴系破坏.论文基于已建立的水力机组轴系暂态计算模型,构建完整的水力机组仿真系统,研究在机组紧急停机暂态过程中,机组角速度的变化与轴承刚度、轴系阻尼系数之间的关系,以及轴系参数对发电机转子和水轮机转轮振动幅度的影响.仿真表明,发电机转子和水轮机转轮振动幅度与机组转速变化趋势一致,在最大转速时振幅达到最大,建议将该点作为安全校核点.  相似文献   

10.
为分析短路故障下燃气轮发电机组轴系的扭振特性,建立了系统的机电耦合非线性数学模型,进行了发电机三相短路故障下轴系扭振及扭矩瞬态响应的数值分析。此外,进一步研究了轴系扭转刚度、发电机定子电阻值、励磁电流初始值等参数对发电机出口端三相短路时系统瞬态扭振的影响。分析结果表明:三相短路时,发电机产生的瞬变电磁转矩的最大值为额定转矩的6倍;电磁转矩在轴系内激发出的瞬态扭矩最大值取决于轴系的固有频率裕度,15%的固有频率裕度时的最大瞬态扭矩较10%的固有频率裕度降低了一倍;而发电机的定子电阻值只改变扭振的衰减时间常数,不改变其最大幅值,电磁转矩最大值和扭转角最大值近似与励磁电流初值的二次方成正比。研究结果可为燃气轮机发电机组轴系的设计提供参考。  相似文献   

11.
Electromagnetic excitation in high power density permanent magnet synchronous motors (PMSMs) due to eccentricity is a significant concern in industry; however, the treatment of lateral and torsional coupled vibrations caused by electromagnetic excitation is rarely addressed, yet it is very important for evaluating the stability of dynamic rotor vibrations. This study focuses on an analytical method for analyzing the stability of coupled lateral/torsional vibrations in rotor systems caused by electromagnetic excitation in a PMSM. An electromechanically coupled lateral/torsional dynamic model of a PMSM Jeffcott rotor is derived using a Lagrange–Maxwell approach. Equilibrium stability was analyzed using a linearized matrix of the equation describing the system. The stability criteria of coupled torsional–lateral motions are provided, and the influences of the electromagnetic and mechanical parameters on mechanical vibration stability and nonlinear behavior were investigated. These results provide better understanding of the nonlinear response of an eccentric PMSM rotor system and are beneficial for controlling and diagnosing eccentricity.  相似文献   

12.
In this paper, we analyze the interaction between friction-induced vibrations and self-sustained lateral vibrations caused by a mass-unbalance in an experimental rotor dynamic setup. This study is performed on the level of both numerical and experimental bifurcation analyses. Numerical analyses show that two types of torsional vibrations can appear: friction-induced torsional vibrations and torsional vibrations due to the coupling between torsional and lateral dynamics in the system. Moreover, both the numerical and experimental results show that a higher level of mass-unbalance, which generally increases the lateral vibrations, can have a stabilizing effect on the torsional dynamics, i.e. friction-induced limit cycling can disappear. Both types of analysis provide insight in the fundamental mechanisms causing self-sustained oscillations in rotor systems with flexibility, mass-unbalance and discontinuous friction which support the design of such flexible rotor systems.  相似文献   

13.
用三线摆测定物体对非质心轴的转动惯量   总被引:3,自引:1,他引:2  
对三线摆的线性近似模型和转动惯量计算公式的由来作了简要说明. 分析了三线摆扭振系统 质心偏移对转动惯量测试的影响,给出了扭振系统质心与三线摆中心轴对齐的判别准则和用 三线摆测定物体对非质心轴转动惯量的工程实用方法. 通过工程实例说明了该方法的有效性 与可靠性. 最后讨论了提高转动惯量实测精度的几项具体措施.  相似文献   

14.
对包含不同类型裂纹(横裂纹、横-斜裂纹以及任意斜裂纹)的转子的耦合振动进行研究,以揭示裂纹转子在不同方向上刚度参数的变化规律及其交叉耦合机理,特别是由此引发的振动特征. 对于包含不同类型裂纹的转子轴段,采用六自由度Timoshenko梁单元模型对其进行单元建模,并基于应变能理论推导计算柔度参数和刚度矩阵. 在此基础上, 采用纽马克-$\beta$数值算法求解裂纹转子的运动方程,获得裂纹转子在单故障或多故障激励(不平衡激励、扭转激励或不平衡激励加扭转激励)作用下的耦合振动响应,进而分析耦合振动谱特征. 与横裂纹和横-斜裂纹相比,任意斜裂纹使转子刚度矩阵的交叉耦合效应更显著,导致转子发生更强烈的弯-扭耦合甚至是纵-弯-扭耦合振动.无论是在不平衡激励还是扭转激励作用下, 弯曲振动与扭转振动幅度都更大. 而且,包含不同类型裂纹的转子的耦合振动特征频率,例如旋转基频与二倍频、扭转激励频率及其边带成分的幅值,对裂纹面方向角具有不同的敏感性. 所得的这些研究结果,可以为转子裂纹的特征参数辨识与诊断提供理论依据.   相似文献   

15.
Interaction of a rotor with a stationary part is a kind of serious malfunction that could result in a catastrophic failure if remained undetected. Past analytical and numerical simulation work on rotor?Cstator interactions mainly focus on the vibrations along the lateral directions. The torsional degree of freedom (dof) is usually ignored. The present work is aimed to study the influence of a rotor to stator contact on the lateral-torsional coupled vibrations. A mathematical model consisting of interacting vibratory systems of rotor and stator is presented. The contact is modeled using contact stiffness, damping and Coulomb friction. Equations derived for kinetic, potential and dissipation energies and non-conservative external forces are used in the Langrange??s equations for deriving the motion equations for the rotor?Cstator system. Equations revealed that the lateral-torsional motion coupling exists twofold for the rotor. The unbalance couples lateral-torsional motion of rotor through inertia and damping matrices. Coupling due to the rotor?Cstator friction occurs through a force vector. The nonlinear equations are solved using a Runge?CKutta fourth-order numerical integration scheme using relatively small time step. Results obtained through the proposed model are compared with the identical rotor?Cstator system without torsional dof and differences are identified. Effect of several parameters such as speed, relative inertia, coefficient of friction and contact damping on the bifurcation behavior of the rotor?Cstator motion has been investigated. Vibration motions presented in the forms of spectrum cascade of the coast-up response, and orbit and Poincaré plots of the steady-state response are exhibiting rich dynamic behavior of the system.  相似文献   

16.
Rotor-shaft systems are subject to non-uniform spin speed during start-up, coast-down or any non-stationary situation changing the spin speed suddenly, e.g., load fluctuation or sudden mass-loss like loss of a blade or a part thereof. For a flexurally and torsionally compliant rotor-shaft, the dynamics under non-uniform spin-speed shows inertial coupling among transverse and torsional coordinates through mass-unbalance and gyroscopic effect. This results into coupled transverse-torsional vibration, where torsional response consists of significant harmonic components at bisynchronous spin frequency, torsional natural frequency of the shaft, and at combination frequencies corresponding to sum and difference of spin and transverse natural frequencies and twice the transverse natural frequency of the rotor-shaft. As a result of the coupling, transverse rotor motion also influences the torsional motion. The Method of Multiple Scales (MMS) is used in this work to carry out an analysis of a simplified system to get an idea about the dominant frequencies of excitation. Results of numerical simulation are presented next to show the effectiveness and influence of actively controlling the transverse rotor motion on its torsional motion, at the dominant frequencies, with the help of non-contact electromagnetic force from an actuator. Transverse vibration control is also observed to control the torsional oscillations due to coupled nature of the problem. The Stability Limit Speed (SLS) of the system is also increased as a result of application of the active control action. Constant axial torque is observed to diminish the influence of coupling, and protect the system against torsional instability, but control action is a must to stabilize the transverse vibration of the system above SLS.  相似文献   

17.
转子扭转-纵向耦合振动分析   总被引:3,自引:1,他引:2  
针对某转子的模型,分析了扭转-纵向耦合振动.计算结果表明:设置转子预应力与旋转时的离心力相对应,其扭转振动频率将随预应力的增大而增大.转子纵向振动频率不受该预应力的影响,这是因为转子旋转时预应力的方向与轴线垂直.随着转子旋转时预应力的变化,扭转振动频率接近纵向振动频率,出现扭转-纵向耦合振动.  相似文献   

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