Computation of the Field in an Axial Gap, Trapped-Flux Type Superconducting Electric Machine

The Bulk Superconductivity Group at the University of Cambridge is currently investigating the use of high temperature superconductors in wire and bulk form to increase the electrical and magnetic loading of an axial gap, trapped flux-type superconducting electric machine. The use of superconducting materials in electric machines can lead to increases in efficiency, as well as power density, which results in reductions in both the size and weight of the machine. In this paper, the authors present a method to compute the field in such an electric machine generated by an array of fully magnetized bulk superconductors. Analytical expressions are derived for the field that would exist in the coil region of the motor, which will act as a powerful tool for carrying out parametric analysis of the motor´s design and performance.