Dynamic Characteristics of Levitated YBCO Bulk Running Above the Permanent Magnet Guideway With Fluctuating Magnetic Field

The dynamic characteristics of high-Tc superconducting magnetic levitation train (HTS-Maglev) are of great significance for future engineering applications. In this article, the dynamic characteristics of the HTS-Maglev are studied by measuring the variation amplitude of the levitation force on the running speed using an HTS-Maglev levitation simulation platform, where the distribution of the magnetic field of the permanent magnet track is uneven. The stability of the superconducting bulk at various running speeds and with different field cooling heights (FCHs) is analyzed by using the time domain, frequency domain, and Lyapunov exponent calculation. The levitation force is found reduced by the fluctuated magnetic field as the FCH is larger than the working height. The unstable phenomena of the system are observed at a running speed equivalent to a driving frequency of 25, 400, 466, and 490 Hz. The movement of the YBCO bulk shows typical chaotic characteristics with a positive Lyapunov exponent when the FCH is greater than 50 mm and the running speed reaches 180 km/h.