中文摘要：

异步起动永磁同步电动机的三相供电电压不对称时,永磁体的退磁情况会受到影响。该文采用复数电压不平衡因数（CVUF）描述三相供电电压的不对称程度,利用二维有限元法研究了三相供电电压不对称时异步起动永磁同步电动机的退磁特点。为了准确反映永磁体发生局部不可逆退磁的情况,采用永磁体的最小工作点（即永磁体各点磁密沿磁化方向投影的最小值）反映永磁体的退磁状态。分析CVUF对永磁体最严重退磁工作点（即电机的最严重退磁磁场出现时的永磁体最小工作点）以及电机稳态运行时定子电流的正序和负序分量、永磁体最小工作点曲线的平均值和波动的影响,并得到了相应的结论。

英文摘要：

If the line-start permanent magnet synchronous motor（LSPMSM） is fed by three-phase unbalanced voltages, magnets＇ demagnetization status will be affected. This paper took complex voltage unbalance factor（CVUF） to describe the unbalanced degree of three-phase supply voltages, and analyzed the demagnetization characteristics of LSPMSM fed by three-phase unbalanced voltages, adopting two-dimensional finite element method（2-D FEM）. In order to accurately appraise magnets＇ partial irreversible demagnetization, this paper used magnets＇ minimum operating point, which is the minimum value of the projection of flux density in the magnetization direction for all points of magnets, to reflect magnets＇ demagnetization status. The effect of CVUF on magnets＇ severest demagnetization operating point, which is magnets＇ minimum operating point when the severest demagnetization field occurs, the positive and negative sequence stator currents as well as the average value and variation of magnets＇ minimum operating point curve at steady state was analyzed, and relevant conclusions were drawn.