Trapped Field Measurements of Gd-Ba-Cu-O Bulk Superconductor in Controlled Pulse Field Magnetizing

摘要

For large-scale electric power application of the melt-processed high temperature superconductor (HTS) bulks, especially at rotating machine, development of trapping much higher magnetic elds by using pulsed magnetization technique is essential. It is di cult to use static eld cooling (FCM) technique that is most e ective magnetizing method for the general industrial HTS applications, because the FCM requires large-scale superconducting magnets. Because the rise in temperature due to the magnetic flux motion decreases the pinning force, we controlled the magnetic flux penetrating to the bulk for the e ective magnetization. A couple of vortex-type copper coils applied a magnetic eld to a Gd-Ba-Cu-O bulk, which dimension was 45 mm in diameter and 19 mm in thickness. HTS bulk was magnetized by the controlled pulse eld without passive LCR pulse. We controlled waveform by using the discharge current that IGBT chopper in pulse magnetizer intermitted. We applied the pulse magnetic eld with the various risetime to the HTS bulk in liquid nitrogen. The various conditions of the controlled waveform pulse to trap well-dressed pro le magnetized the Gd-Ba-Cu-O bulk, strongly at 77 K. In the present study, we show several properties which was measured in the PFM of the HTS bulk.