Hysteretic Rotating Characteristics of an HTS Induction/Synchronous Motor

We report on hysteretic rotating characteristics of a 20 kW class high-temperature superconducting induction/synchronous motor, which is operated in liquid nitrogen (77 K). We show that the hysteretic characteristic shows the peak value of power conversion efficiency in decreasing primary voltage from the appropriate higher one. We also develop an analysis model based on a motor's voltage equation, in which the nonlinear current transport property of the high-temperature superconductor windings is taken into account. Our report shows the possibility of higher efficiency control of the motor by effective utilization of the aforementioned hysteretic behavior