Semi-analytical modeling AC loss of a flat stack of Y-Ba-Cu-O tapes

We propose semi-analytical models to compute alternating current (AC) power loss in a stack of N high-temperature superconductor YBa2Cu3O7−x (or Y–Ba–Cu–O) tapes subjected to a time-varying magnetic field perpendicular to the tapes with zero transport current. The models take into account screening of the interior superconducting tapes of the stack from the external magnetic field. We validate the results by experiments carried out at temperature T=77.2K under an applied magnetic field with the amplitude of its induction Bext=0.57T and frequencies up to 110 Hz. As follows from our models, the AC loss per tape in stacks of N tapes decreases with N in agreement with experiments. The approach is extended to compute the AC loss for lower temperatures, larger magnetic fields strengths, and for frequencies up to several kHz. These studies are important for understanding and predicting the AC loss for contemporary motors and generators.