Development of flux pump-based supply systems for superconducting coils

Conventional power supplies for superconducting magnets rely on dissipative power electronic converters and current leads, which are a thermal path connecting room temperature to cryogenic superconductors, as well as an additional source of joule dissipation, thereby imposing a significant heat load on the cooling system. Flux pumps offer a contactless, low-voltage, and high-current alternative to power electronics exciters and current leads solutions. However, as flux pumps physical mechanism is complex and counterintuitive, their engineering process and development of viable and executive designs have proved to present major challenges. This Ph.D. project focused on numerical modeling, investigation, and engineering analysis of flux pumps. The research aimed to address gaps in scientific research surrounding the technology and its potential disruptive impact on enabling contactless and efficient energization of superconducting magnets. First, a numerical model was developed and validated against experimental results to unveil the intricacies related to voltage rectification in traveling field flux pumps. The model embeds artificial intelligence methods to address the relationship between critical current and n-value of HTS tapes concerning temperature and magnetic field. A new complete equivalent circuit was derived and exploited for fast system-oriented analysis of flux pumps. The numerical model was further exploited to develop an application-oriented optimal design procedure for traveling field flux pumps, which was tested to design and characterize a HTS dynamo and a linear flux pump for real applications. The study found that the performance of the flux pumps is highly dependent on the rated current and its total resistance and discussed the influence of these two load parameters on the viability of flux pumps. Overall, this Ph.D. project aimed to overcome the empirical approach with which flux pumps have been designed and analyzed for decades and applied a systematic engineering method to facilitate its implementation in real applications.