Eddy current modeling in multifilementary superconductive tapes submitted to external time varying magnetic field
Résumé
Evaluating AC loss in high-temperature superconductors (HTSs) is crucial for the design of superconductive devices such as cables, fault current limiters, transformers or motors. Given the complexity of the modelled structures, numerical methods are often necessary [1]. However, usual numerical schemes have convergence problems when the modelled system involves multiscale dimensions or highly anisotropic material properties, which is usually encountered in superconductive devices. In this case, specific numerical schemes are often necessary.
In previous works, we have successfully developed an electromagnetic model, based on an integro-differential formulation, for eddy current computation in highly anisotropic material, applied to eddy current computation in layered carbon fiber reinforced composite polymers. In this work, the formulation is adapted to model eddy currents losses in a multifilamentary superconductive tape submitted to external time varying magnetic field. This is achieved by defining an effective electrical conductivity tensor for the superconductive tape [2-3].
[1] Francesco Grilli, Enric Pardo, Antti Stenvall, Doan N. Nguyen, Weijia Yuan, and Fedor Gömöry, “Computation of Losses in HTS Under the Action of Varying Magnetic Fields and Currents”. IEEE Trans. on Applied Superconductivity, Vol. 24, No. 1, February 2014.
[2] Naoyuki Amemiya, Naoto Enomoto, and Shunsuke Shirai “FEM Analysis of AC Loss in Twisted Bi-2223 Multifilamentary Tapes Carrying AC Transport Current in AC Transverse Magnetic Field with Arbitrary Orientation”. IEEE Trans. on Applied Superconductivity, Vol. 14, No. 2, June 2004
[3] Eunguk Lee, M.S, “AC loss in superconducting composites: continuous and discrete models for round and rectangular cross sections, and comparison to experiments”. PHD Dissertation, Graduate School of the Ohio State University, 2004.