内置式永磁同步电机转子故障对定子电磁振动的影响

发布时间：2018-06-08 22:03

本文选题：内置式永磁同步电机 + 结构强度　；参考：《重庆大学》2016年硕士论文

【摘要】：内置式永磁同步电机因高效率、高能量密度以及运行可靠等诸多优点,在高速大功率场合,诸如空调、电动汽车、船舶和航天航空,其应用越来越普及。内置式永磁同步电机的转子机械结构较为复杂,磁钢置于转子内侧受到转子保护,但是转子隔磁桥处于转子边缘承受较大应力,从而需要分析其强度。转子发生故障,定子的电磁振动特性会随之变化,进而为故障诊断提供检测依据。这使得内置式永磁同步电机转子故障下的电磁振动特性逐渐成为业界倍受关注的科研方向和研究课题。本文是国家自然科学基金面上项目“基于定子电磁振动与电流分析的永磁同步电机电气及失磁故障诊断方法研究”(51477015)中失磁故障诊断方法的基础研究内容。本文主要分析内置式永磁电机转子故障下定子的电磁振动,考虑到转子机械结构复杂,先对转子结构强度进行分析,然后分析转子故障(主要包括失磁故障以及偏心故障)对定子电磁振动的影响。首先,本文在介绍弹性力学、结构动力学和电磁场基本理论的基础上,建立永磁电机转子灌注环氧树脂以及不添加环氧树脂的模型,同时搭建永磁电机特有的转子故障模型,即失磁故障以及偏心故障。其次,计算转子临界转速,并分析在磁钢不同安装工艺下,转子最大应力的变化,特别分析环氧树脂被破坏后,转子所受最大应力的变化,从而校核永磁电机的转子强度。分析表明,若在磁钢与转子间隙中灌注环氧树脂,不仅能够加固转子结构,还会减小转子承受的最大应力;即使环氧树脂受到破坏,依旧能够减小转子所受的最大应力。然后,本文重点研究了电机在不同程度失磁故障下的振动特性,并与电机未失磁时的振动对比。结果表明,单个磁钢失磁故障下,定子振动的低频分量会增大,致使振动加剧。定子在单个磁钢均匀失磁时的振动比在单个磁钢局部失磁时的振动要剧烈。当单个磁钢均匀失磁达到一定程度时,定子的振动不再继续显著加剧。而所有磁钢局部失磁时,定子振动变化较小。最后,计算分析电机在不同程度偏心故障下的电磁振动,同时与电机未偏心时的振动做对比。分析表明,电机在静态偏心故障下,定子的形变呈轴对称分布,其对称轴是由定子中心与旋转中心确定的直线。随着静态偏心的加剧,定子的形变量增大。电机在动态偏心故障下,定子振动的低频分量显著增大。随着动态偏心程度的加剧,定子振动的高次谐波以及分数次谐波会显著增大。
[Abstract]:Due to its advantages of high efficiency, high energy density and reliable operation, built-in permanent magnet synchronous motor (PMSM) is widely used in high speed and high power applications, such as air conditioning, electric vehicles, ships and aerospace. The mechanical structure of the rotor of the built-in permanent magnet synchronous motor is complex, and the magnetic steel is protected by the rotor on the inner side of the rotor, but the rotor magnetic isolation bridge is subjected to great stress at the rotor edge, so the strength of the rotor needs to be analyzed. The electromagnetic vibration characteristics of the stator will change with the fault of the rotor, which can provide the basis for fault diagnosis. This makes the electromagnetic vibration characteristics of built-in permanent magnet synchronous motor (PMSM) rotor fault gradually become the research direction and research topic of the industry. This paper is the basic research content of the fault diagnosis method of permanent magnet synchronous motor (PMSM) based on stator electromagnetic vibration and current analysis, which is a project of National Natural Science Foundation of China (NSFC), namely, the method of fault diagnosis of permanent magnet synchronous motor (PMSM) based on stator electromagnetic vibration and current analysis (51477015). This paper mainly analyzes the electromagnetic vibration of the stator under the rotor fault of the built-in permanent magnet motor. Considering the complex mechanical structure of the rotor, the strength of the rotor structure is analyzed first. Then the influence of rotor fault (including loss of magnetic field and eccentricity) on stator electromagnetic vibration is analyzed. Firstly, on the basis of introducing the basic theories of elasticity, structural dynamics and electromagnetic field, the models of permanent magnet motor rotor perfusion epoxy resin and non-epoxy resin are established, and the special rotor fault model of permanent magnet motor is built. Loss of magnetic fault and eccentric fault. Secondly, the critical speed of the rotor is calculated, and the change of the maximum stress of the rotor under the different installation process of magnetic steel is analyzed, especially the change of the maximum stress of the rotor after the epoxy resin is destroyed, so as to check the rotor strength of the permanent magnet motor. The analysis shows that if epoxy resin is poured into the gap between magnetic steel and rotor, it can not only strengthen the rotor structure, but also reduce the maximum stress of the rotor, even if the epoxy resin is damaged, the maximum stress of the rotor can still be reduced. Then, this paper focuses on the vibration characteristics of the motor under different degree of loss of excitation, and compares the vibration of the motor with that of the motor without losing magnetic field. The results show that the low frequency component of stator vibration increases and the vibration intensifies when a single magnetic steel loses its magnetic field. The vibration of stator is more intense when a single magnetic steel loses its magnetic field uniformly than when a single magnetic steel loses its magnetic field locally. When the uniform loss of magnetic field of a single magnetic steel reaches a certain degree, the vibration of the stator no longer increases significantly. However, the stator vibration change is small when all the magnets lose their magnetic field locally. Finally, the electromagnetic vibration of the motor under different eccentricity faults is calculated and analyzed, and compared with that of the motor without eccentricity. The analysis shows that the stator deformation is axisymmetric distribution under the static eccentricity fault, and the symmetry axis is a straight line determined by the center of stator and the center of rotation. With the increase of static eccentricity, the shape variable of stator increases. The low frequency component of stator vibration increases significantly under dynamic eccentric fault. With the increase of dynamic eccentricity, the higher harmonic and fractional harmonic of stator vibration will increase significantly.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM341

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