Numerical models for AC loss calculation in large-scale applications of HTS coated conductors

TL;DR

This paper develops and compares two computational models for efficiently simulating large-scale high-temperature superconductor (HTS) coil devices with thousands of tapes, significantly reducing simulation time while maintaining accuracy.

Contribution

It introduces a homogenized and a multi-scale model for large HTS coil simulation, enabling faster analysis of devices with hundreds to thousands of tapes.

Findings

Both models speed up simulations by 1-3 orders of magnitude.

The models maintain good accuracy compared to detailed finite element simulations.

They are suitable for design and optimization of large-scale HTS devices.

Abstract

Numerical models are powerful tools to predict the electromagnetic behavior of superconductors. In recent years, a variety of models have been successfully developed to simulate high-temperature-superconducting (HTS) coated conductor tapes. While the models work well for the simulation of individual tapes or relatively small assemblies, their direct applicability to devices involving hundreds or thousands of tapes, as for example coils used in electrical machines, is questionable. Indeed the simulation time and memory requirement can quickly become prohibitive. In this article, we develop and compare two different models for simulating realistic HTS devices composed of a large number of tapes: 1) the homogenized model simulates the coil using an equivalent anisotropic homogeneous bulk with specifically developed current constraints to account for the fact that each turn carries the same current; 2) the multi-scale model parallelizes and reduces the computational problem by simulating only several individual tapes at significant positions of the coil's cross-section using appropriate boundary conditions to account for the field generated by the neighboring turns. Both methods are used to simulate a coil made of 2000 tapes, and compared against the widely used H-formulation finite element model that includes all the tapes. Both approaches allow speeding-up simulations of large number of HTS tapes by 1-3 orders of magnitudes, while keeping a good accuracy of the results. Such models could be used to design and optimize large-scale HTS devices.