Axial Flux Disc Motor Analysis with Polycrystalline Type II Superconducting Materials

The discovery of the superconductivity phenomenon and understanding of electromagnetic properties of high temperature superconducting (HTS) materials allow the optimization and creation of several applications, such as, electrical machines and drives, fault current applications, or superconducting magnetic energy storage, well described in the literature. Electromechanical conversion devices based in HTS materials present reduction in device dimensions or performance improvement for the same active volume, when compared with their conventional ones. An axial type disc motor, with high temperature superconductor (HTS) material in the rotor and conventional armature has been designed and developed. The paper describes simulations and laboratory experiments conducted on an axial flux motor with an polycrystalline YBCO HTS disc rotor at liquid nitrogen temperature (77 K) in order to analyze the motor’s behavior, the electromechanical characteristics and to find a possible equivalent circuit or model that describe it operation. The rotating magnetic field was produced by a conventional four-pole, three-phase stator winding, at 50Hz. From the obtained results it was observed that the tested HTS motor exhibits a conventional hysteresis motor type of behavior, even though the hysteretic phenomena don’t have the same principle. For the model, the proposed approach allows the description of the equivalent electrical circuit as a conventional hysteresis motor, being the model motors’ parameters predicted.