Influence of Jc(B, ${\rm{\theta }}$) on Dynamic Resistance and Total Loss in REBCO Coated Conductors Under Various External Field Orientation

Abstract

There are many high-temperature superconducting (HTS) devices in which REBCO coated conductors (CCs) are exposed to AC external magnetic fields of various orientations while carrying DC currents. The actual REBCO CCs present complex anisotropies and field dependences, but the effects caused by different J _c ( B , ${\rm{\theta }}$ ) on the dynamic resistance and AC loss characteristics are not clear. In this paper, the magnetization loss, dynamic resistance, and total loss of the nearly isotropic Shanghai Creative (SCST) CC and the strongly anisotropic Fujikura (FYSC) CC at 77 K are investigated in the range of 0 ${\rm{^\circ }}$ (perpendicular to the wide surface of the CC) and 75 ${\rm{^\circ }}$ field angles based on H formulation. The results exhibit that the magnetization loss and dynamic resistance of the SCST CC are less dominated by the perpendicular field compared to the FYSC CC. Moreover, as the field changes from 0 ${\rm{^\circ }}$ to 75 ${\rm{^\circ }}$ , the vertical components of both the penetration field and the threshold field for the two CCs vary oppositely. Overall, at near-perpendicular fields, the flux flow resistance first occurs in the FYSC CC, while at near-parallel fields, it appears earlier in the SCST CC. The results also show that large parallel fields increase the proportion of dynamic loss in total loss. These results are expected to give a valuable reference for accurate loss estimation of HTS components such as field windings.