AC Loss Modeling in Superconducting Coils and Motors with Parallel Tapes as Conductor

Many superconducting power applications contain REBa2Cu3O7-x (or REBCO) coils, where RE stands for 'rare earth.' Superconducting motors are very interesting for mobile applications like aviation, thanks to their high power per unit weight. In order to reduce the inductance, multitape conductors are often used in windings but parallel tapes present coupling AC loss. In this article, we analyze the AC loss of single coils and a full stator of a motor made of windings of parallel tapes, taking several coupling situations into account. Our computer modeling method combines self-programmed and commercial finite-element methods to calculate the current density and AC loss. We found that isolating the tapes along the length provides almost the same AC loss reduction as that obtained by full transposition. This reveals that there are still many unexploited strategies to reduce the AC loss in multitape conductors.