Preliminary Design and Simulation of a Superconducting Synchronous Machine for Aircraft Applications

Nowadays, there is a major international motivation driving towards the electrification of the aviation industry to reduce its impact on climate change. One of the most promising possibilities for achieving this ambitious goal involves the use of superconducting electrical machines featuring a high power density. This thesis investigates the preliminary design of an Air-Core Superconducting Synchronous Machine for future aircraft applications. After introducing superconductivity from a macroscopic point of view, the state of the art of superconductors for electrical machine applications is presented. Then, some of the most commonly used modeling methods for the simulation of superconductors are analyzed. Two simple case studies are introduced to understand whether it is necessary to consider specific formulations for the analysis of superconductors in electrical machines. The T-A formulation is first implemented as a benchmark, and it is demonstrated that an alternative approach considering an equivalent constant current density in the superconductor provides similar results, at least from a macroscopic viewpoint. The behavior of air-core synchronous machines is presented afterward. This analysis is useful to have analytical expressions of the field in the machine for the preliminary design. In this work, an already-existing sizing procedure is considered and refined to improve its applicability in the design of air-core synchronous machines. After acquiring the necessary knowledge, the electromagnetic design of a 2.61 MW, 2500 rpm air-core synchronous machine with HTS field windings is carried out. It is proved that, under appropriate assumptions, the well-known sizing equation can be applied even for the design of this type of machine. Moreover, it is shown that the analytical results match well with the ones obtained from FEM simulations.