Design of an Axial Flux Inductor Type Synchronous Motor With the Liquid Nitrogen Cooled Field and Armature HTS Windings

A liquid nitrogen cooled axial flux type high temperature superconducting (HTS) synchronous motor was designed. This motor is an eight-pole inductor type synchronous motor with six armature windings. The field windings and armature windings are made of the BSCCO HTS wires. We called it inductor type flux control superconducting (IFCS) motor, and its output is 400 kW at the rated speed of 250 rpm. Until now, there were few armature windings using HTS wires, because of AC losses generation when the wires are used in the alternating magnetic field. In this motor, we used iron cores to decrease AC loss. Also because of the help of iron cores, it is possible to make use of armature winding at liquid nitrogen temperature. Furthermore, inductors were employed in the rotor. As a result, the cryostats that contain field HTS windings and armature HTS windings can be fixed; also we do not need the excitation devices such as the brushes and slip ring and the cooling devices such as the rotary joint to offer the path for coolant to flow.