High-performance synchronous reluctance motors by local manipulation of the magnetic properties of electrical steel laminations during the laser cutting process

同步磁阻电机被认为是一个可行的替代通常使用的永磁同步电机和感应电机。特别是稀土磁体（例如NdFeB）价格的大幅上涨以及由此导致的永磁电机成本的上升导致了对这种无磁体且因此具有成本效益的电机类型的兴趣增加。然而，同步磁阻电动机的更广泛的应用目前仍然受到相对较低的功率因数和功率密度的限制。高度有限的凸极比（或同步电感比）之间的d轴和q轴磁通可以被认为是主要原因。理论分析表明，减小漏磁导向钢桥的宽度可以获得更高的凸极比。然而，这导致转子的机械稳定性降低。计划中的项目详细分析了这个问题，并旨在通过在激光切割过程中局部操纵电工钢层压性能来显着提高显着率。与机械切割工艺（例如冲压）相比，通过激光切割对金属板进行轮廓加工的特点是具有较高的自由度（切割参数设置）。这为根据电机的面积对磁特性进行最佳局部设置提供了机会。此外，使用激光允许制造用机械方法无法实现的高度细丝结构。本项目详细分析了利用激光切割同步磁阻电机用电工钢片的潜力。在理论和实验中研究了由此产生的对机器的操作行为的影响。该分析也可以转移到其他电机类型（如永磁电机），即使对机器性能的影响较小。该项目的主要目标是在不降低转子机械稳定性的情况下，与当前同步磁阻电机相比，显著增加凸极比（+25%）。这直接导致更高的功率密度和功率因数，因此也导致更高的效率。期望对同步磁阻电机的更广泛应用作出重要贡献。

The synchronous reluctance machine is considered as a viable alternative to typically used permanent magnet synchronous machines and induction machines. Especially the tremendous rising of rare-earth magnet prices (e.g. NdFeB) and the resulting higher costs of PM-machines led to an increased interest in this magnet-free and therefore cost-efficient motor type. However, a broader application of synchronous reluctance motors is currently still prevented by the comparatively low power factors and power densities. The highly limited saliency ratio (or synchronous inductance ratio) between the d-axis and q-axis flux can be considered as the main reason. Theoretical analyses have shown that higher saliency ratios can be achieved by reducing the width of the leakage flux guiding steel bridges. However, that leads to a decreased mechanical stability of the rotor. The planned project analyses this problem in detail and aims for a significant higher saliency ratio by local manipulation of the electrical steel lamination properties during the laser cutting process. Contouring the sheet metal by laser cutting is characterized by a high number of degrees of freedom (cutting parameter set) compared to mechanical cutting processes (e.g. punching). This opens up the opportunity for an optimal local setting of magnetic characteristics dependent on the area of the electric machine. Furthermore, using the laser allows the manufacturing of highly filigree structures that cannot be achieved with mechanical methods. The project deals with detailed analysis of the potentials by using the laser for the cutting process of the electrical steel laminations for application in synchronous reluctance motors. The resulting impact on the operational behaviour of the machine is studied in theory and experiment. The analyses can be transferred to other motor types (e.g. PM-motor) as well, even though a lower influence on the machine behaviour is expected.The main objective of the project is a considerable increase of the saliency ratio (+ 25 %) in comparison to current synchronous reluctance motors without decreasing the mechanical stability of the rotor. This leads directly to higher power densities and power factors and therefore higher efficiencies as well. An important contribution to a more widely application of synchronous reluctance machines is expected.