Additive Manufacturing of electric machines: Research on the potential of additivemanufacturing of PM synchronous machine rotors

增材制造工艺逐层生产部件和组件，而不使用成形工具。该过程在设计部件的几何形状以及设计材料特性方面产生了额外的和新的自由度。该研究项目的重点是使用这些新的自由度来改进电机的设计和制造，特别是永磁励磁同步电机（PMSM）的转子。在以前的研究中，在帕德博恩大学直接制造研究中心（DMRC）和莱布尼茨大学汉诺威的驱动系统和电力电子研究所（IAL）之间的紧密合作下，实现了AM的不同材料系统，其特性及其在电机中的应用的基础知识。本文提出的研究项目涉及“AM材料研究”、“转子设计”、“转子制造”和“转子测试”等领域。在材料研究领域，通过系统的参数研究，确定了适合电机的软磁材料和相应的AM工艺参数。重点在于一个FeCo和两个FeSi合金。为了表征这些材料，应在AM试样上确定其电、磁和结构机械性能。这些结果将用于第二阶段的项目设计的永磁同步电机转子。由于AM而产生的已识别材料特性和设计中的新自由度应用于提高PMSM的可制造性和技术参数，例如，通过转子偏斜而不增加PM漏磁通，以及通过特殊表面成形减少转子表面上的涡流。对于这些新的AM转子概念，电磁和机械设计都需要设计规则。在项目的第三阶段，原型转子应由AM制造，如果需要，还应进行机械或热后处理。最后，这些转子将通过实验进行评估，以验证预测的电磁和机械性能和操作行为，例如扭矩密度，效率和扭转强度。为了证明增材制造对电机制造的好处，应通过模拟和测量与传统制造的转子进行比较。

Additive manufacturing processes produce components and assemblies layer by layer without using formative tools. This process generates additional and new degrees of freedom in designing the geometry of the components as well as in designing the material properties. The focus of this research project is to use these new degrees of freedom for improving the design and manufacturing of electrical machines, especially of rotors of permanent magnet excited synchronous machines (PMSM). In previous research, fundamental knowledge on different material systems for AM, their characterization and their application in electrical machines were achieved in tight cooperation between the University of Paderborn's Direct Manufacturing Research Center (DMRC) and the Institute for Drive Systems and Power Electronics (IAL) of Leibniz Universität Hannover. The research project proposed here addresses the fields 'material research for AM', 'rotor design', 'rotor manufacturing' and 'rotor test'. On the field of material research, suitable soft magnetic materials for electrical machines and the respective process parameters for AM are identified by means of systematic parameter studies. The focus lies on one FeCo and two FeSi alloys. In order to characterize these materials, their electrical, magnetic and structural mechanic properties shall be determined on AM test specimen. These results shall be used in the second phase of the project for designing rotors of PMSM. The identified material properties and the new degrees of freedom in design due to AM shall be used to improve the manufacturability and the technical parameters of PMSM, e.g. by rotor skewing without increasing the PM leakage flux and by reducing eddy currents on the rotor surface with a special surface shaping. For these new AM rotor concepts, design rules are required for both, electromagnetical and mechanical design. These shall be elaborated in order to care for robust design and easy manufacturability.In the third phase of the project, prototype rotors shall be manufactured by AM and, if required, mechanical or thermal postprocessing. Finally, these rotors will be evaluated by experiment in order to validate the predicted electromagnetical and mechanical properties and operational behaviour, e.g. torque density, efficiency, and torsional strength. In order to demonstrate the benefits of AM for electrical machine manufacturing, comparisons shall be made to conventionally manufactured rotors by simulation as well as by measurement.