Computation of Superconducting Stacks Magnetization in an Electrical Machine

Superconducting technology offers the prospect of sharply increasing power density of rotating electrical machines, especially in the low-speed, high-torque range, with impact in applications such as wind energy and aircraft propulsion. Among the enabling technologies, stacks consisting of piled up layers of high-temperature superconductors may provide a source of magnetic flux density for torque production, without the complexity of superconducting wound rotor poles. For this to happen, careful designs optimizing electromagnetic, mechanical, and thermal aspects at the same time must be developed. In that sense, this paper applies a recently developed combined electromagnetic formulation to compute the magnetization level of high-temperature superconductor stacks installed in the airgap of an electrical motor after field cooling magnetization. The results, congruent with the applied field, show a strong interaction between the teeth and stacks and provide a way of initializing the state of the machine prior to operation.