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

Abstract

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. Index Terms-Axial flux type, BSCCO-HTS wire, inductor type flux control superconducting (IFCS) motor, liquid nitrogen coolant, stator cooling system.

Present Status and Future Perspective of Bismuth-Based High-Temperature Superconducting Wires Realizing Application Systems

“…91,92) One typical example developed in Japan is the axialtype motor, i.e., the world's most powerful 365 kW HTS motor cooled with liquid nitrogen. This motor used Bi-2223 armature windings 93,94) constructed with a novel idea of a flux collector. Figure 20 shows the images and the structure of this motor.…”

Performance of Inverter Fed HTS Induction-Synchronous Motor Operated in Liquid Nitrogen

“…The parameters and are, correspondingly, the primary and secondary leakage inductances. As can be seen in (1), is in proportion to the function of , That is, the voltage for the constant torque becomes smaller by decreasing the driving frequency. As a result, the pull-in voltage becomes smaller correspondingly.…”

“…Especially, the ship propulsion systems have been considered to be one of the most promising applications for such high performance motors [1], [2]. Although there exist some kinds of wound motors as conventional types, e.g., DC motor, synchronous motor, induction motor, the HTS synchronous one has mostly been developed so far.…”

Perspectives on Electric Machines with Cryogenic Cooling

“…Superconducting synchronous machines (SCSMs): These are synchronous machines that use superconducting windings in their rotor or stator. They can be used as generators [8] or motors [17], and provide high power density, high efficiency, and high power factor. Studies have shown that SCSMs can achieve efficiency levels of 99% at full load [7], compared to conventional motors that typically operate at around 94-96% efficiency;…”