Reluctance machines incorporating high temperature superconducting materials on the rotor

The computer modelling of reluctance machines with rotors containing both iron and high temperature superconducting (HTS) materials, using the finite element method (FEM), is presented in this paper. The modelling permits to obtain the field and stator current distribution from where reluctance torque is evaluated. Different solutions are analyzed and experimental results on a 2 kW reluctance motor using HTS materials on the rotor and cooled by liquid nitrogen, show a significant increase in the torque values, when compared with that of a correspondent conventional machine. Pre-magnetization of these rotors by field cooling is explained and this process gives a mechanical output power undoubtedly better than that of a conventional reluctance machine.