High Temperature Superconducting Maglev Measurement System

Abstract

Melt-textured rare-earth Ba-Cu-O (REBCO, RE=Nd, Sm, Eu, Gd, etc.) bulk samples have high critical current density and high critical magnetic flux, which can produce a strong levitation force and a stable equilibrium. The high temperature superconducting (HTS) REBCO bulk may be cooled using liquid nitrogen instead of liquid helium to reduce the initial construction and running cost in practical application systems. This makes HTS bulks particularly attractive for the applications in magnetic bearings (Moon, 1990), flywheel energy storage devices (Bomemann, 1995), and Maglev vehicle (Wang J. et al., 2002). In order to investigate the magnetic levitation properties (levitation force, guidance force, trapping flux, and so on) of the HTS Maglev vehicle over a permanent magnet (PM) guideway, SCML-01 HTS Maglev measurement system was developed at the Applied Superconductivity Laboratory (ASCLab) of Southwest Jiaotong University in China (Wang J. et al., 2000). The measurement system includes a liquid nitrogen vessel, a permanent magnet guideway (PMG), data collection and processing capabilities, a mechanical drive and an Autocontrol feature. The bottom wall of the vessel has a thickness of 3.0 mm. The PMG has a length of 920 mm, for which its magnetic induction reaches up to 1.2 T. The measuring process is controlled by a computer. The SCML-01 measurement system is capable of performing real time measurements of Maglev properties through a combination of one or many YBaCuO bulks and one PM or several PMGs. This set up was especially employed on board the HTS Maglev equipment over one and two PMGs. The on board Maglev equipment includes a rectangular-shaped liquid nitrogen vessel containing YBaCuO bulk superconductors. Based on the original research results (Wang J. & S. Wang, 2005a; Song, 2006) from SCML-01, the first man-loading HTS Maglev test vehicle in the world was successfully developed in 2000 (Wang J. et al., 2002). After 2004, several HTS Maglev vehicle prototypes over a PMG followed in Germany, Russia, Brazil, Japan and Italy (Schultz et al., 2005; Kovalev et al., 2005; Stephan et al., 2004; Okano et al., 2006; D’Ovidio et al., 2008). Given the lack in measurement functions and measurement precision of the SCML-01, after five years, the HTS Maglev Measurement System (SCML-02) with more functions and higher precision was developed to extensively investigate the Maglev properties of YBaCuO bulks 3