中文摘要：

针对双边空心式永磁直线伺服电机推力波动受到气隙磁场影响的问题。研究该电机空载气隙磁场的分析求解方法。采用等效磁化强度法对双边空心式永磁直线伺服电机的气隙磁场进行求解，推导出气隙和磁极区域中磁场的解析公式。将解析分析与有限元分析结果进行比较，验证解析法的计算结果的准确性。根据气隙磁密的解析公式，分析了3个主要尺寸——永磁体宽度Tm、永磁体高度hm和气隙高度δ对空载气隙磁场的影响。分析表明，永磁体高度hm和气隙高度δ主要影响电机气隙磁场大小，对磁场谐波含量影响较小，而永磁体宽度Tm对磁场的大小和谐波含量的影响都很显著。通过对永磁体宽度Tm的优化设计，可以有效改善电机气隙磁场分布的正弦性，从而减小电机的推力波动。

英文摘要：

For the thrust fluctuation of the double side air-cored permanent magnet linear servo motor （PMLSM） being influenced by the air-gap magnetic field, the analysis and solving method of the no-load air-gap magnetic field was studied. An analytical method, equivalent magnetization intensity （EMI） method, was applied to solve the magnetic field of the PMLSM. The analytical equations of the magnetic flux density in the air-gap and PM regions were derived. The analytical solutions were proved accurate by comparing the analytical solutions with the finite element analysis （FEA） solutions. Based on the analytical equations of the magnetic flux density, the influences of three major dimensions, the magnet width Tm, magnet thickness hm and the air-gap thickness δ,on the magnetic field was analyzed. It is shown that, hm and δ mainly influence the magnitude of the magnetic field, while Tm influences both the magnitude of the field and the harmonic content of the magnetic filed remarkably. The distribution condition of the magnetic field in the air-gap could be improved effectively by optimal design of the Tm ; furthermore the thrust fluctuation is reduced.