Armature winding analysis for high-temperature superconducting PM-excited AC machines

The design considerations of AC machines with windings made of high-temperature superconductors (HTS) are presented in the following paper. The considerations were narrowed to permanent-magnet excited machines, although the results can be extrapolated to many other machine types as general guidelines. The influence of basic machine parameters and coefficients during the design of such machines are considered in order to estimate operating conditions of HTS windings. The number of poles, number of slots or slot dimensions, coil placement, and arrangement, are taken into account with the intent to fully utilize features of superconducting materials such as the capability of conducting high current density without significant losses. The attention is placed on low power machines, below 1 kW, operating at liquid nitrogen temperature (77 K). For analysis purposes, the finite element method (FEM) is used to calculate the distribution of the magnetic field and its effect on the critical current of the HTS coil. The numerical analysis is carried out in ANSYS software.