Numerical Analyses on the Influences of Armature Winding Shape and Yoke Arrangements on Total Losses in Fully Superconducting Synchronous Motors Using REBCO Tapes

In the fully superconducting synchronous motors using REBCO tapes, the magnetic fields in the direction of perpendicular to the face of the tapes in armature windings generate large ac losses in the windings. Therefore, it is effective to reduce magnetic fields in the direction of perpendicular to tape face for the reduction of ac losses. A one of the methods is to get closer a yoke to the armature windings as possible. However, installing the yoke in the cooling area in order to get closer the yoke to the armature windings substantially increase the iron loss in the yoke by the cooling penalty. Therefore, in general, the yoke is placed at room temperature. The purpose of this paper is to evaluate the effect of installing the yoke in low temperature. So, we analyzed the properties of 500-kW fully superconducting synchronous motor by finite element method. We estimated the influences of installing yoke into low temperature in the two cases of armature winding shapes, solenoid windings and pancake windings. In this calculation, we assumed that superconducting material is EuBCO, and the operating temperature is 65 K.