基于多尺度法的电机转子在不平衡磁拉力作用下的自由振动特性分析

发布时间：2018-06-22 12:20

本文选题：不平衡磁拉力 + 多尺度法　；参考：《机械工程学报》2017年16期

【摘要】：即使动平衡精度很高的电机转子,其质量偏心可忽略,但由于车用永磁同步电机工况复杂,换段过程、路面不平度、发动机激励等都可对转子系统形成径向扰动,转子将产生自由涡动,引起动态偏心,进而不平衡磁拉力对电机转子系统的自由涡动产生影响。根据转子系统的刚度特性讨论了动力学方程中非线性项系数以确定多尺度法的应用条件,利用该方法得到了不平衡磁拉力作用下转子系统自由振动的解析解并研究其振动特性。由于不平衡磁拉力的非线性使得转子正反自由涡动的复振幅是时变的,其大小保持常数不变而其相位随时间线性变化,其变化率取决于正反涡动的振幅,这将导致正反涡动的频率降低。若正反涡动振幅大小相等且非零则正反涡动频率相等,转子中心运动轨迹为直线;若正反涡动振幅有一个为零,则转子中心轨迹为圆;更一般的情况是正反涡动振幅大小不等且均不为零,两种涡动产生耦合其频率也不再相等,转子自由涡动的轨迹是一个旋转的近似椭圆其位移分量产生调幅现象。当转子涡动振幅不大时,利用多尺度法获得的解析解与数值计算结果吻合较好具有较高的精度。
[Abstract]:Although the mass eccentricity of motor rotor with high dynamic balancing accuracy can be neglected, the rotor system can be disturbed by radial disturbance due to the complex working conditions, changing process, road roughness, engine excitation, etc. The rotor will produce free vortex, cause dynamic eccentricity, and then unbalance magnetic pull force will affect the free vortex of motor rotor system. According to the stiffness characteristics of the rotor system, the nonlinear coefficients of the dynamic equation are discussed to determine the application conditions of the multi-scale method. The analytical solution of the free vibration of the rotor system under unbalanced magnetic pull is obtained and the vibration characteristics of the rotor system are studied by using this method. Because of the nonlinearity of unbalanced magnetic pull force, the complex amplitude of the rotor's forward and inverse free vortex is time-varying, its magnitude remains constant and its phase changes linearly with time, and the rate of change depends on the amplitude of the positive and negative vortex. This will result in a decrease in the frequency of positive and negative eddies. If the amplitude of the positive and negative vortices is equal and the frequency of the positive and negative vortices is equal, the trajectory of the rotor center is straight line, if the amplitude of the positive and negative vortices is zero, the trajectory of the center of the rotor is circular. More generally, the amplitude of both positive and negative vortices is not equal, and the frequency of coupling is no longer equal. The trajectory of rotor free vortex is an approximate ellipse of rotation and its displacement component produces amplitude modulation phenomenon. When the rotor vortex amplitude is small, the analytical solution obtained by the multi-scale method is in good agreement with the numerical results.
【作者单位】：北京理工大学机械与车辆学院;
【基金】：国家自然科学基金资助项目(U1564210,51375047,51305026)
【分类号】：TM341

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