动圈式磁悬浮永磁平面电机磁场解析分析与参数设计

Analytical Magnetic Field Analysis and Parameter Design for Magnetically Levitated Permanent-magnet Planar Motors with Moving-coils

针对动圈式磁悬浮永磁平面电机定子磁场谐波含量较大的问题,提出了一种根据实际气隙磁密与期望气隙磁密的平均相对均方差对磁钢参数进行优化设计的方法。通过磁钢阵列的磁密谐波模型分析了定子磁场的3维磁密分布,获取不同水平高度上的平均基波幅值,从而构建了磁钢阵列的期望基波模型;基于谐波模型和期望基波模型,计算了磁钢阵列的实际气隙磁密与期望气隙磁密的平均相对均方差;在此基础上,根据"平均基波幅值应尽可能大、平均相对均方差应尽可能小"的原则设计了磁钢参数。有限元仿真和试验样机实测结果表明,该设计方法对于降低动圈式磁悬浮永磁平面电机定子磁场的高次谐波含量,特别是降低2次谐波具有明显效果。

In order to reduce higher harmonic of magnetic field in magnetically levitated permanent-magnet planar motors with movingcoils,a novel principle of magnet parameter design was proposed,which was based on the average relative mean-square deviation between the real magnetic density and expected air-gap magnetic density. According to harmonic model of magnetic field,the three-dimensional magnetic density of this magnet arrangement was analyzed and then the average fundamental amplitude in different height levels was calculated. The expected fundamental model of this magnet arrangement was then presented,which together with the obtained harmonic model giving the average relative mean-square deviation between the real magnetic density and expected air-gap magnetic density. The principle of magnet parameter design was presented,which could be described as'to achieve the maximum average fundamental amplitude and minimum average relative mean-square deviation as far as possible'. Finally,the finite element simulation and measured results of the experimental prototype illustrated that the presented design method has a good inhibitory effect on the higher harmonics,especially on the second harmonic.