永磁体形状对可变磁通记忆电机调磁参数影响

Influence of Permanent Magnet Cross Section Shape on Field-Control Parameters of Variable Flux Memory Motor

采用有限元方法对不同永磁体截面形状的可变磁通记忆电机空载和直轴去磁磁场分布进行了分析,详细描述了转子内的旁路磁通和零磁通密度区域的变化情况。在此基础上,研究了永磁体形状改变对每极最大气隙磁通、气隙磁通密度、永磁体中心线上的磁通密度以及最大去磁安匝数等调磁参数的影响。结果表明合理选择永磁体形状可以显著提高永磁体的利用率;永磁体形状系数小于约0.6时,容易实现对永磁体有效去磁,而永磁体截面形状接近矩形时则应该将整个永磁体工作点去磁到拐点以下才能保证去磁效果。该成果有助于此类电机的合理设计和控制。

In this paper, the magnetic field distributions of a variable flux memory motor （VFMM） with different rotor permanent magnet （PM） cross section shapes under no-load and d-axis demagnetization are analyzed by finite element method. A detailed description on the changes of bypass flux and zero flux density area in the rotor is given. The influence of PM cross section shape on the field-control parameters of VFMM, such as the maximum air gap flux per pole, the air gap flux density, the maximum demagnetizing ampere-turns, and the flux density on the centerline of PM are numerically investigated. It is found that the utilization ratio of PM can be considerably improved by choosing a reasonable PM section shape. When the PM cross section shape coefficient is less than 0.6, the demagnetization effect of PM can be guaranteed easily. When the PM shape approaches rectangular, to ensure the validity of PM demagnetization, the working point of PM should be demagnetized below the knee point. The conclusions obtained by this paper will be helpful to the design and control of VFMM.