A LOCAL THERMAL ANALYSIS OF AN AC ARMATURE WINDING OF A HIGH TEMPERATURE SUPERCONDUCTOR MOTOR

Abstract

The new generation of airborne High Temperature Superconductor (HTS) synchronous electric motors employs AC copper "air windings" hosted in an iron-less stator, which is siege of intense power dissipation by Joule and variable magnetic field effects. Prototyping a low weight/volume HTS motor leads then to a complex thermal design of the AC winding that may exceed the level of detail requested by standard electrical machines. In order to provide for the thermal stability of the motor, a detailed knowledge of the temperature field, beyond the information delivered by the standard lumped circuit model, is essential. This paper reports a preliminary, local, numerical analysis of a cooling concept that solves the heat flow problem in a critical part of the air-winding armature. The paths and mechanisms of heat transfer, the thermal load structure unveiled by numerical simulation are used to generate a finer resolution lumped thermal network that may be used in the design phase of the prototype.