气隙偏心下永磁电机转子系统的振动特性分析

研究气隙偏心对永磁同步电机转子系统振动特性的影响。建立了气隙偏心下转子的动力学模型,结合永磁同步电机在带负载工作下转子永磁体及电枢电流共同形成的气隙磁场分布情况,利用Maxwell应力张量法计算了气隙偏心造成的不平衡磁拉力,并代入转子系统运动方程;通过实例分析,详细讨论了不同偏心以及负载类型对转子系统振动特性的影响。结果表明:质量偏心在增大转子振动的同时会削弱不平衡磁拉力的影响,使振动趋于规则;初始静偏心的大小和方向都将影响转子振动特性,当其方向和重力方向相反,振动强度将有所减弱;当外部负载转矩发生变化,其相应谐波频率的振动将被激发出来。

Analysis on vibration characteristics of the rotor of permanent magnet motor with Air-Gap Eccentricity

This paper investigates the vibration characteristics of the rotor system of permanent magnet synchronous motor with air-gap eccentricity. A dynamic model of the rotor system is built. According to the distribution of magnetic flux density generated by permanent magnet and armature current under load, Unbalanced Magnet Pull (UMP) is calculated with the Maxwell stress tensor and is substituted into the dynamic model. From several illustrating numerical examples, the effects of different eccentricities and loads on rotor vibration are discussed in detail. The results show that, the mass unbalance weakens the effect of the UMP while aggravates the vibration of the rotor, the magnitude and orientation of the initial eccentricity can also change the vibration characteristic of the rotor, and the vibration will be weakened when the orientation of initial eccentricity is close to the direction of the gravity. As the load changes, the corresponding vibration components will be excited with the same frequencies as those of the load.