Numerical Computation of AC Losses and Flux Profiles in High-Aspect-Ratio Superconducting Strips in Perpendicular AC Magnetic Field

Abstract

We present the results of finite-element modeling of a YBCO thin-film superconductor deposited on a nonmagnetic substrate and on a weakly ferromagnetic substrate. The model was implemented using commercial software to calculate the ac loss in the presence of a sinusoidal external magnetic field applied perpendicular to the surface of the superconducting tape. A strategy is demonstrated to overcome the difficulties in the finite-element method due to the high aspect ratio of the YBCO film by using the computed values of ac loss for thicker samples to extrapolate the results to the actual physical thickness of the superconductor (∼1 μm). The effect of the width of the weekly ferromagnetic substrate upon the ac loss of the superconductor film has also been studied.

Current carrying capability of HTS Roebel cable

“…Actual thickness of the superconductor is 1 lm, but [15] considers thickness of 100 lm, and [16] considered many different values of thickness ranging from 6 lm, to 400 lm. The conclusion is, as long as one considers critical current density, J c of sample as total critical current of the wire divided by the cross-section area of the sample considered in the model, error made is very small.…”

“…At the onset of current-free region, both B y and J z have logarithmic singularity and get infinite slope at the boundary [17], (dJ z /dx, dB y /dx) = infinity. This appears as a spike at the boundary in the H-formulation in COMSOL [16] where cell sizes are small. Similar behaviour for B y is also reported in the numerical and measured results of [19] at low current in a single tape.…”

Development of a three-dimensional finite-element model for high-temperature superconductors based on the H-formulation

“…In particular, the H-formulation [1,2] has increased in popularity both in the academic and the industrial world and it has been successfully used to study the ac loss performance not only of individual wires, but also of more complex systems like cables and coils [3][4][5]. The model has been adapted to take into account the presence of ferromagnetic materials as well [6,7].…”

Numerical Modeling and Experimental Analysis of AC Critical Current in YBCO-Coated Conductors

“…Combine the Maxwell's equation with E-J constitutive law, the frequency dependence of I-V characteristics was obtained. The modeling technique has been described in [9], [10]. The electric field is plotted against the applied transport current.…”