A full-range formulation for dynamic loss of high-temperature superconductor coated conductors

Abstract

Dynamic loss is significant for evaluating the performance of type-II high-temperature superconductor (HTS) coated conductors (CC), especially when used in electric machines. Although analytical expressions of dynamic loss have been proposed and verified for HTS CCs exposed to low external magnetic fields with a low current load rate, the non-linearity of dynamic loss at high current load ratios and simultaneous high magnetic fields is still unclear and cannot be predicted by the existing analytical equations. This paper proposes a completely new formulation to characterize the non-linearity of dynamic loss taking into account the J c(B) dependence of CCs, which can be used for full ranges of both magnetic fields and current load ratios. The proposed analytical formulas have been verified by a T -formulation based numerical model and experiments. This paper comprehensively demonstrates the variation of dynamic loss and provides a meaningful reference of loss controlling for HTS CCs, which is vital for HTS machine windings to avoid quench.