Design and Analysis of Cooling Structure on Advanced Air-Core Stator for Megawatt-Class HTS Synchronous Motor

A general high-temperature superconducting synchronous motor (HTSSM) is designed and manufactured with an air-core structure, which eliminates the laminated iron core to concentrate the linkage flux in conventional rotor and stator. In an air-core structure, a nonmagnetic material such as glass fiber-reinforced plastic (GFRP) is used as an armature winding supports to avoid saturation of magnetic field density in the stator core and to reduce the weight and harmonics of the motor. However, GFRP air-core supporters make heat dissipation difficult due to the very low thermal conductivity of GFRP, which makes sustainable and stable operation of HTSSMs impossible. Therefore, in this paper, the concept of advanced air-core stator (AACS) is presented to enhance the cooling performance of a conventional GFRP air-core stator. The AACS concept pertains to the introduction of thermal conductive materials on an armature supporter to replace the GFRP material of a conventional air-core stator. The AACS concept structure for a 1.5-MW-class HTSSM was designed and analyzed using three-dimensional electromagnetic and thermal finite element method.