Development of superconducting tape stacks for implementation in contactless magnetic bearings with high rotational speed

基于高温超导体（HTSC）的超导磁轴承（SMB）是飞轮、超导电机或液化气泵等节能旋转设备以及纺织机械中新的高速无摩擦技术的关键部件。到目前为止，这种轴承使用昂贵的大块HTSC块，由于耗时的制造过程，这种块的可用性有限。在过去的几年里，带堆栈制备的高温超导涂层导体被讨论作为一个合适的替代散装材料在悬浮应用。在这里，最先进的涂层导体被切割成碎片，并堆叠在彼此之上。这种带堆叠的应用预示着显著进步的高潜力，如更紧凑的轴承设计、更高的设计灵活性、改进的热性能和机械强度、更高的可用性和超导体的降低的成本。与此同时，这一方法也面临重大挑战，值得进行彻底的科学研究。它们特别涉及导体的几何形状，所述导体由在显著较厚的衬底上的二维超导层组成，导致堆叠中的超导多层结构，这影响了所考虑的功能特性。因此，我们的项目的主要重点是研究在高速旋转超导磁轴承的高温超导磁带堆栈的实现。一个主要目的是有效地制备这种堆栈与不同的磁带安排，以研究其一般性质和这些堆栈与轴承中使用的典型磁场配置的相互作用。它将伴随着堆栈的属性和磁体与超导体之间的力的相互作用的数值建模。这允许为轴承选择最合适的胶带堆叠，并指定未来轴承特定导体材料的要求。第二个主要目标是研究高温超导带堆在一个真实的SMB的性能，比较它们与标准的散装材料。因此，这些堆栈将集成到为纺织机应用而设计的现有SMB设置中。将进行静态和动态测量，以确定轴承性能，从而确定磁带堆叠与散装相比的优势和挑战。同样，实验研究将伴随着设置的数字建模，这也使得轴承本身的未来设计优化成为可能。总之，我们预计拟议的项目将为SMB系统中涂层导体材料的节能技术应用做出重大贡献，这将扩大这种高品质材料的应用范围。它还可能引发对材料本身的特定优化的追求，以提高要求苛刻的悬浮应用的性能。

Superconducting magnetic bearings (SMB) based on high-temperature superconductors (HTSC) are a key component for energy-efficient rotating devices as flywheels, superconducting motors or liquid gas pumps as well as for new high-speed friction-free technologies in textile machinery. So far, such bearings use expensive bulk HTSC blocks having a limited availability due to the time-consuming fabrication process. Within the last years, tape stacks prepared from HTSC coated conductors are discussed as a suitable alternative for bulk material in levitation application. Here, state-of-the-art coated conductors are cut into pieces and stacked above each other. The application of such tape stacks promises a high potential for significant advances as a more compact bearing design, a higher design flexibility, improved thermal performance and mechanical strength, higher availability and reduced costs of the superconductor. At the same time, this approach has important challenges, which deserve a thoroughly scientific study. They are particularly related to the geometry of the conductor consisting of a two-dimensional superconducting layer on a significantly thicker substrate resulting in a superconducting multilayer architecture in the stack, which influences the functional properties in view. Therefore, the main focus of our project is to study the implementation of HTSC tape stacks in high-speed rotational superconducting magnetic bearings. A major objective is the efficient preparation of such stacks with different tape arrangements to study their general properties and the interaction of these stacks with a typical magnetic field configuration used in bearings. It will be accompanied with numerical modelling of the stack’s properties and the force interaction between the magnet und the superconductor. This allows to select the most appropriate tape stacks for the bearing and to specify the requirements of bearing-specific conductor materials in the future. The second major objective is to study the properties of HTSC tape stacks in a real SMB to compare them with standard bulk material. Therefore, the stacks will be integrated in an existing SMB setup designed for applications in textile machines. Static and dynamic measurements will be performed to determine the bearing properties, which allows to identify the advantages and challenges of the tape stack in comparison to bulks. Again, the experimental studies will be accompanied by a numeric modelling of the setup, which enables also a future design optimization of the bearing itself. In summary, we expect the proposed project to generate a significant contribution to the application of coated conductor material in SMB systems for energy-efficient technologies, which will extend the application range of this high-quality material. It might also trigger the quest for a specific optimization of the material itself to improve the performance for demanding levitation application.