The Bi-2212 round wire has a multifilamentary structure, and the use of numerical method to study ac loss of such multifilamentary superconducting wire requires a long calculation time and large memory. Adopting a homogenization method at low frequency to study the ac loss of multifilamentary structural wire/tape has been proven to have high enough accuracy and can save a lot of calculation time. With the expansion of the application range of superconducting materials, however, superconducting power devices exceeding the frequency of tens of kHz have huge potential applications in the future such as wireless power transfer. Therefore, it is necessary to study the applicability of the homogenization model at high frequencies. This article mainly presents an ac loss numerical study of Bi-2212 round wire at wider frequency (50 Hz–500 kHz) by homogenization method. The homogenization is achieved by two different methods. The first method is to treat the superconducting bundle and the Ag matrix between the bundles as a superconducting domain (bundle-matrix homogenized model, BHM). The second method is to regard the Ag matrix between the superconducting filaments and the filaments as a superconducting domain (filament-matrix homogenized model, FHM). In order to evaluate the feasibility of the two different homogenization methods, we compare the calculation results of the two different homogenization models with the original model, OM. The results show that the FHM can effectively improve the calculation speed while satisfying the high calculation accuracy. This conclusion can be used to quickly evaluate the ac energy loss of large-scale superconducting devices at wider frequencies.

中文翻译：

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Bi-2212 圆线在高达 500 kHz 的宽频率范围内的交流损耗

Bi-2212圆线具有复丝结构，采用数值方法研究这种多丝超导线材的交流损耗需要较长的计算时间和较大的内存。采用低频均质化方法研究复丝结构线/带的交流损耗已被证明具有足够高的精度，可以节省大量计算时间。然而，随着超导材料应用范围的扩大，超过几十kHz频率的超导功率器件在未来具有巨大的潜在应用，例如无线电力传输。因此，有必要研究匀化模型在高频下的适用性。本文主要通过均质化方法对Bi-2212圆线在较宽频率（50 Hz-500 kHz）下的交流损耗进行数值研究。均质化是通过两种不同的方法实现的。第一种方法是将超导束和束之间的Ag矩阵视为超导域（束-矩阵均质化模型，BHM）。第二种方法是将超导灯丝与灯丝之间的Ag矩阵视为超导域（filament-matrix homogenized model，FHM）。为了评估两种不同均质化方法的可行性，我们将两种不同均质化模型的计算结果与原始模型OM进行了比较。结果表明，FHM在满足较高的计算精度的同时，可以有效提高计算速度。