Potential for Torque Density Maximization of HTS Induction/Synchronous Motor by Use of Superconducting Reluctance Torque

We try to realize the ultimate maximization of torque density in a high-temperature superconducting induction/synchronous motor (HTS-ISM) for transportation equipment. Although the basic structure of the HTS-ISM is almost the same as that of the conventional squirrel-cage induction motor, it can rotate at high-efficiency synchronous speed by the use of superconducting (zero resistance) rotor windings. It has been also shown that torque density can be enormously enhanced at such synchronous rotation mode. In this study, in order to further enhance such torque density, a rectangular superconducting bulk shield is installed in the rotor core. First, we clarified the effectiveness of the HTS bulk based on the analysis and the experiment. Moreover, we succeeded in obtaining no-load and load curves for the speed range from 300 to 1800 r/min.