Higher harmonics in the voltage on a superconducting wire carrying AC electrical current

Abstract

The problem of determining the harmonic content in the voltage that appears on a superconducting wire carrying cosine-like AC current was resolved theoretically, using two approaches. First, the Fourier components of the voltage spectrum were found by numerical integration. Importance of individual terms was established, leading to two conclusions: a) it is the cosine component of the 3rd harmonic that represents the bulk of harmonic distortion, b) for the practical purposes it is su¯cient to consider higher harmonics with n µ 7. Then, the analytical formulas were derived. While for the sine components a general expression containing an in nite series was found, closed-form formulas were derived for the cosine components of the harmonics 1, 3, 5, 7. Consequences of the results to the experimental technique used to study the AC transport properties of superconductors are discussed.

Influence of field-dependent critical current on harmonic AC loss analysis in HTS coils for superconducting transformers supplying non-linear loads

“…For this purpose, several theoretical studies have been done in order to analytically calculate the AC loss under nonsinusoidal current. In [29][30][31], authors tried to derive a rather simple and straightforward closed form equation based on harmonic orders to calculate the AC transport losses of the HTS tapes. In [32], the AC losses in racetrack coil which is made by YBCO tapes have been measured for nonsinusoidal transport currents with fundamental frequencies up to 1 kHz.…”