轴向磁化永磁微电机磁场分析及设计方法研究

在轴向磁化永磁电机设计中,为研究尺寸效应对其性能的影响,采用有限元方法对这种双转子电机的磁场进行了仿真计算,得出了轴向磁化永磁电机转子的气隙磁密波形分布。分析了转子外形尺寸、充磁极数、磁体厚度和气隙长度对气隙磁密的影响,即随着气隙长度的增加,充磁极数多的其气隙磁密幅值的减小幅度大于充磁极数少的;随着磁体厚度的增加,气隙磁密为一上升曲线,当磁体厚度达到某一点时,气隙磁密幅值基本为一常数;减小转子直径时,随着磁体厚度的降低,平均半径处气隙磁密幅值的减小幅度越来越不明显,但为不使气隙磁密波形变形严重,永磁转子径向长度需至少大于1.5 mm。磁场分析结果可对该类电机微小型化过程中的设计起指导作用。对计算结果做了理论分析,并将计算结果和实验结果进行了比较,计算值和实测值基本一致。

Design method and magnetic field analysis of axial-magnetized permanent magnet micromotor

In order to investigate the impact of the size effect on its performance in designing axial-magnetized permanent magnet micromotor, the finite element method was adopted to simulate the magnetic field of this kind of dual rotor motor, and the flux density wave form distributed in the airgap was obtained. The influences of the external dimensions, pole numbers and magnet thicknesses of the rotor and the airgap distances on the flux density were analyzed, the analytical results were given. With the increasing of the airgap distance, the flux density under more poles reduces more quickly than under fewer poles. With the increasing of the magnet thickness, the flux density is a rising curve, and after the magnet thickness gets to a certain point, it is almost a constant. While reducing the diameter of the rotor, the decreasing of the flux density is slower and slower with the reducing of the magnet thickness. The results of the magnetic field analysis can guide the design of the micromini-aturization of the motor. Moreover, the results are analyzed theoretically and the simulated values are almost consistent with the experimental values.