Dynamic resistance is essential to evaluate the performance of high-temperature superconducting (HTS) coated conductors, especially when applied in synchronous electric machines and HTS flux pumps. The analytical expression of dynamic resistance has been proposed and verified in many cases, and it appears that dynamic resistance R_dyn is in a linear correlation with transport current I_t and the amplitude of external ac magnetic field B_ext. However, some experimental data have shown that the linearity of R_dyn(I_t) and R_dyn(B_ext) curves only exists within a certain range. To quantitatively describe this interval, the lower demarcation current I_dl, the upper demarcation current I_du, and the corner field B_cor have been defined in this article with explicit formulas. The proposed demarcation currents and the corner field, which is used to characterize the nonlinearity of dynamic resistance, have been validated by the simulation and experimental measurements. This article further adds upon the existing knowledge regarding the interaction of dynamic resistance with transport current and magnetic field, which is particularly significant for accurate loss controlling in HTS magnets, rotating machines, and flux pumps.

中文翻译：

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高温超导涂层导体动态电阻的分界电流和角场

动态电阻对于评估高温超导 (HTS) 涂层导体的性能至关重要，尤其是在应用于同步电机和 HTS 磁通泵时。动态阻力的解析表达式已经在很多情况下被提出并得到验证，似乎动态阻力电阻_dyn与传输电流呈线性相关我_Ť 和外部交流磁场的幅度 乙_分机。然而，一些实验数据表明，线性电阻_动态(我_Ť） 和 电阻_动态(乙_ext ) 曲线只存在于一定范围内。为了定量描述这个区间，下分界电流一世_dl , 上分界电流一世_du和角域乙_cor已在本文中用明确的公式定义。所提出的分界电流和角场用于表征动态电阻的非线性，已通过模拟和实验测量得到验证。本文进一步补充了有关动态电阻与传输电流和磁场相互作用的现有知识，这对于 HTS 磁体、旋转电机和磁通泵中的精确损耗控制特别重要。