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.