Critical Current Estimation of HTS Coil Considering the Tape Inhomogeneity and Different Criteria

HTS Tape's critical current (
I_c
) inhomogeneity has important effect on estimation accuracy of the
I_c
of HTS coil. It is essential to choose a suitable characterization on the inhomogeneity for precisely estimating the
I_c
. This paper is devoted to this aspect. Firstly, several characterizations on the tape's
I_c
inhomogeneity are introduced. Based on the homogenized self-consistent model, the
I_c
of four HTS double pancake coils is calculated with consideration of varied characterizations and two criteria, i.e., MAX and AVG criteria. Subsequently, these HTS coils are fabricated and measured. By a comprehensive comparison on the
I_c
between calculation and measurement, we finally determine the appropriate characterizations on the inhomogeneity for estimating the
I_c
of coil during the design and operation stages. It was proved that the using of the mean
I_c
of tape and MAX criterion is appropriate for obtaining a conservative estimation on the
I_c
of coil during the design stage. By contrast, the combination of the overall
I_c
of tape and AVG criterion can better reproduce the measured
I_c
of coil and thus gives a more accurate evaluation on the operation performance of HTS coils.