Dynamic response of high-temperature superconducting magnetic levitation under real seismic wave excitation

The high-temperature superconducting (HTS) pinning magnetic levitation (maglev) system achieves passive and stable levitation through the coupling between HTS bulks and permanent magnet guideway (PMG), which gives it great development potential in the field of high-speed rail transit. Nevertheless, safety considerations are also crucial for the HTS maglev transportation system. Currently, there is a lack of research on the operational safety of HTS maglev trains during some extreme situation like earthquakes. Thus, this paper uses an experimentally-verified electromagnetic-thermal-mechanical model to simulate and study the variation law of the temperature rise of HTS bulks under the action of the Trinidad seismic waves (including the individual actions of longitudinal waves and transverse waves, as well as their combined action). The results show that a temperature rise of approximately 0.09 K occurs in the left and right bulk materials when longitudinal waves act alone. The comprehensive effect will cause a lateral drift of 0.6 mm. When transverse waves act alone, the temperature rise of the left and right bulks reaches 0.15 K. Compared with vertical vibration, lateral vibration increases the likelihood of the bulks experiencing a quench, thereby posing a risk of the bulks hitting the PMG. When longitudinal and transverse waves act simultaneously, the temperature rise of the left and right bulks is 0.18 K, which is significantly lower than the 92 K critical temperature for quenching. Thus, under seismic wave conditions, the temperature rise of the bulks in HTS maglev system is extremely small, with a maximum of only 0.18 K. In the existing bath cooling mode of HTS pinning maglev, this temperature rise will not cause HTS bulks to quench. However, it is essential to prevent the decline in levitation performance caused by the change in temperature rise, as this decline may lead to the risk of the bulks hitting the PMG. These findings offer valuable insights into thermal stability, which are beneficial for the future practical implementation of HTS maglev systems.