【目的】分数槽集中绕组(FSCW)感应电机在运行过程中会出现转子偏心问题，产生非主导极的气隙磁密，导致径向电磁力密度发生变化，进而产生使电机遭到损坏的不平衡磁拉力(UMP)。针对此问题，本文以一台定子15槽转子18槽且定转子均为FSCW的感应电机为研究对象，对电机的气隙磁密、径向电磁力密度和UMP进行了研究。【方法】首先，介绍了转子偏心产生的原因和带来的影响，并运用磁势-磁导法推导出了气隙磁密的表达式，分析了理想状态下和静偏心故障下气隙磁密的谐波组成；其次，通过Maxwell方程得到了径向电磁力密度和UMP的表达式；然后，利用Ansys-Maxwell对FSCW感应电机进行二维有限元建模分析；最后，采用定子闭槽的方法来优化气隙磁密，进而抑制UMP。【结果】电机转子偏心不但引入了电机在理想状态下运行时所没有的3的倍数次谐波，还改变了主波幅值，但谐波的频率不发生变化；电机发生静偏心故障时组成径向电磁力密度的谐波次数为在理想状态下运行时的谐波次数±1，且径向电磁力密度的幅值远大于理想状态；径向电磁力密度和UMP会随着偏心距离的增大而增大；相较于定子开槽，定子闭槽时电机的气隙磁密平均值减小，定子齿谐波含量大幅减小，UMP平均值下降了21.83%。【结论】转子偏心是产生UMP的主要原因。采用定子闭槽法，电机的气隙磁密得到优化，定子齿谐波含量减小从而使径向电磁力密度降低，最终电机的UMP也得到降低

[Objective] Fractional slot concentrated winding (FSCW) induction motors may experience rotor eccentricity during operation, leading to the generation of air-gap flux density of non-dominant pole. This results in variations in radial electromagnetic force density, further inducing unbalanced magnetic pull (UMP), which can cause damage to the motor. To address this issue, this paper investigates the air-gap flux density, radial electromagnetic force density, and UMP of an FSCW induction motor with a 15-slot stator and an 18-slot rotor, where both the stator and rotor are FSCW. [Method] First, the causes and effects of rotor eccentricity were introduced, and the air-gap flux density expression was derived using the magnetomotive force-permeance method, followed by an analysis of its harmonic components under ideal conditions and static eccentricity fault conditions. Then, Maxwell's equations were used to obtain expressions for radial electromagnetic force density and UMP. A two-dimensional finite element model of the FSCW induction motor was developed using Ansys-Maxwell for analysis. Finally, closing the stator slot was proposed as a method to optimize the air-gap flux density and suppress UMP. [Results] Rotor eccentricity introduced additional harmonics that were multiples of three, which did not exist under ideal operating conditions, and altered the fundamental wave amplitude without changing the harmonic frequencies. When a static eccentricity fault occurred, the harmonic orders of radial electromagnetic force density shifted to ±1 of those in the ideal state, and the amplitude increased significantly. Moreover, radial electromagnetic force density and UMP increased with the eccentricity value. Compared to stator with slots, the average air-gap flux density of the motor decreased under stator with closed slots, the stator tooth harmonics were significantly reduced, and the average UMP decreased by 21.83%. [Conclusion] Rotor eccentricity is the primary cause of UMP. By adopting the stator slot closure method, the air-gap flux density is optimized, significantly reducing stator tooth harmonics and lowering radial electromagnetic force density, ultimately mitigating UMP.

中国博士后科学基金面上项目(2017M621086);江苏省配电网智能技术与装备协同创新中心开放基金项目资助(XTCX202405)