Multiphysics Modeling of High-Temperature Superconducting Power and Magnet Applications

High-Temperature Superconductors (HTS) have emerged as a promising technology for next-generation electrical machines, especially motors with racetrack coils in the stator, due to their high power density and improved power-to-weight ratio. However, the practical deployment of HTS motors faces critical challenges, most notably the phenomenon of thermal quenching.This refers to the localized loss of superconductivity due to heat generation, which can be triggered by AC losses, short-circuit DC voltages, or screening currents induced during high-frequency operation. These electrothermal instabilities not only compromise motor performance but can also lead to irreversible damage to the superconducting coils if not properly mitigated.The main focus of this PhD research is to conduct a comprehensive electromagnetic and electrothermal analysis of HTS racetrack coils within stator configurations, especially under fault conditions. The study places particular emphasis on understanding the quench behavior and associated heat transfer mechanisms when the coils are integrated with the motor environment and in direct contact with cryogenic coolant. By analyzing the coupled behavior of current density, temperature rise, and power loss distributions, this work aims to reveal the intricate interdependencies between electrical and thermal phenomena in operational and fault scenarios.To achieve this, a robust and computationally efficient software was developed in C++, integrating the Minimum Electro-Magnetic Entropy Production (MEMEP) based on the variational principle for solving the electromagnetic problem and the Finite Difference Method (FDM) for thermal modeling. The coupled model enables the accurate prediction of electrothermal responses under dynamic operational conditions, providing valuable insights into quench initiation and propagation. The electrothermal model was rigorously benchmarked against the METEP method and other established analytical and numerical techniques, demonstrating strong agreement andreliability.Through detailed case studies and parametric investigations, this thesis contributes novel understanding and practical tools for the safe design and operation of HTS motors, with a focus on quench detection, risk mitigation, and thermal management. The findings support the development of next generation HTS machines that are both high-performing and resilient, paving the way for broader adoption of superconducting technologies in real-world electric power and propulsion systems.