Speaker
Description
An analytical approach is used to calculate the AC losses of round superconducting cables subjected either to external fields applied perpendicularly to the cable length. Losses for fields applied in one fixed direction but varying sinusoidally in time are compared to losses for applied fields with fixed (with time) amplitudes that rotate around the sample (rotating around an axis parallel to the cable length). Such losses are then calculated for fields which both rotate around the sample and have an amplitude which varies with rotation angle. It is shown that rotating fields can be treated as a superposition of orthogonally applied fields in some cases.
The influence of the shape of the strands that make up the cable are explored, with a round strand shape compared to a tape-like geometry. AC losses are divided into hysteresis loss, coupling loss, and eddy current loss, and the effects of both sample and field geometry are explored for each loss component. At last, the proposed analytical method is used to calculate the AC losses of some samples, and the results are compared with those from the numerical simulation based on Comsol Multiphysics and experimental data quantitatively.