The key technology of the air-core monopole linear motor (AMLM), a core component of precision motion systems, is the distribution of the electromagnetic structure and cooling structure. Thus, AMLM can achieve small thrust fluctuation, high thrust density, and low surface temperature rise. Consequently, the multiobjective optimal design of AMLM under the multiphysical fields has become the key technology of AMLM. Consideration of the strict requirements of AMLM model calculational accuracy will cause an excessively long computation time for the finite-element analysis (FEA) software three-dimensional (3-D) model, and it is not convenient for an optimal computation of the multiphysical fields model. Therefore, a surface magnetic charge model and an image method are proposed in the paper to establish an air gap magnetic field model of AMLM. The saturation characteristic of magnetic materials can be reflected through saturation coefficient of the model. In addition, the air gap field distribution status of AMLM can be better predicted. An AMLM thermal field model is established by adopting the thermal network method. In the model, the heat transfer coefficient of cooling water is calculated based on the current curve obtained from the FEA software. Parametric modeling was performed on the AMLM electromagnetic and cooling structure through definition of 7-D proportionality coefficients. Based on the aforementioned electromagnetic field and the thermal field model, genetic algorithm (GA) was adopted for AMLM optimization design by setting cooling capacity and size as constrain conditions as well as by setting thrust density, thrust fluctuation, mover's mass, and motor constants as optimization objects. The AMLM electromagnetic field, the accuracy of thermal field model, and the validity of the AMLM optimization method were verified through simulation and tests. The method proposed has significantly improved the efficiency of optimization calculation.

中文翻译：

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基于多物理场的空芯单极直线电机建模与优化


空心单极直线电机（AMLM）是精密运动系统的核心部件，其关键技术是电磁结构和冷却结构的分布。因此，AMLM可以实现推力波动小、推力密度高、表面温升低。因此，多物理场下AMLM的多目标优化设计成为AMLM的关键技术。考虑到AMLM模型计算精度的严格要求，会导致有限元分析（FEA）软件三维（3-D）模型计算时间过长，不方便多物理场的优化计算模型。因此，本文提出表面磁荷模型和图像方法来建立AMLM的气隙磁场模型。磁性材料的饱和特性可以通过模型的饱和系数来反映。此外，可以更好地预测AMLM的气隙场分布状况。采用热网络法建立了AMLM热场模型。模型中，根据FEA软件得到的电流曲线计算冷却水的传热系数。通过定义 7 维比例系数，对 AMLM 电磁和冷却结构进行参数化建模。基于上述电磁场和热场模型，采用遗传算法（GA）进行AMLM优化设计，以冷却能力和尺寸为约束条件，以推力密度、推力波动、动子质量和电机常数为优化对象。 通过仿真和测试验证了AMLM电磁场、热场模型的准确性以及AMLM优化方法的有效性。所提出的方法显着提高了优化计算的效率。