Electromagnetic evaluation and quantification of welding processes for the packaging of electrical steel

电机的功率密度和效率是由芯材的磁性决定的。旋转电机的磁芯是由隔离的电工钢片制成的，这些钢片是包装和固定的。因此，不仅初始条形材料的性能对其应用至关重要，而且它们的加工也至关重要，因为它会影响磁化强度和磁损耗。目前采用的封装技术有粘合、联锁和焊接。由于多余的非磁性材料，粘接导致较小的堆积系数。联锁导致电短路，从而增加涡流。这会导致磁性质的恶化。焊接会导致微观结构的变化、残余应力和电隔离的局部破坏。焊接对电工钢磁性能的影响在文献中没有全面的描述。本项目的目的是对电工钢包装的焊接过程进行电磁评价和量化。激光焊接是一种能量冲击较小的焊接工艺，因此本文的研究重点是激光焊接。工艺改进包括激光点焊和真空焊接。在常规焊缝的基础上，研究和讨论了包装过程中焊点的统计和几何分布。为了量化影响，在模型中考虑了现象学影响，包括制造和磁性能变化。在考虑抗扭强度要求的情况下，采用从焊接到磁性能的模拟链对电工钢焊接接头进行量化和评价。

The power density and efficiency of electrical machines is determined by the magnetic properties of the core material. Magnetic cores of rotating electrical machines are manufactured from isolated electrical steel laminations that are packaged and fixated. Thus, not only the properties of the initial strip material are crucial for their application, but also their processing, because it affects the magnetization and magnetic losses.Currently, gluing, interlocking and welding are used as packaging technology. Gluing leads to smaller stacking factors, due to the excess non-magnetic material. Interlocking leads to electric short circuits, which increases eddy currents. This leads to a deterioration of magnetic properties. Welding leads to a change in microstructure, residual stress and local destruction of electric isolation.The effect of welding on the magnetic properties of electrical steel is not comprehensively described in literature. The aim of the project is an electromagnetic evaluation and quantification of welding processes for the packaging of electrical steel. Focus of this study is put to laser welding, as a welding process is with a small energy impact. Process modifications include laser spot welding and welding in vacuum. Besides conventional welding lines, a statistical and geometrical distribution of welding spots is studied and discussed as packaging pro-cess. For the quantification of the effects, the phenomenological impacts are comprised in model that includes the manufacturing as well as the magnetic property change. A simulation chain from the welding to the magnetic properties is used for quantification and evaluation of welding joints of electrical steel with consideration of the required torsion strength.