Measurement of levitation force of high-temperature superconducting maglev under high-speed operation condition

High-temperature superconducting (HTS) pinning magnetic levitation (maglev) has garnered significant attention in high-speed maglev transportation due to its inherent self-stability, low energy consumption, and absence of mechanical friction. Ensuring the safe and stable operation of HTS pinning maglev systems necessitates a dedicated focus on the performance and stability of HTS bulks levitated above the permanent magnetic guideway (PMG). Previous research has indicated that variations in the temperature within the HTS bulk can impact the levitation performance of the system. This temperature-related phenomenon occurs when the external magnetic field applied to the HTS bulk changes. However, it is noteworthy that previous levitation force tests for HTS magnetic levitation systems have been limited to quasi-static or low-speed studies. The exploration of dynamic levitation forces, particularly at high speeds, has remained constrained due to the associated high costs. Therefore, the objective of this study is to investigate dynamic levitation forces while the HTS pinning maglev system is in motion at high speeds, utilizing a self-developed ultra-high-speed maglev test rig. Initially, the relationship between the levitation force and the vertical displacement of the HTS pinning maglev system is examined based on quasi-static experiments. Subsequently, comparative studies are conducted to measure levitation forces at varying speeds. Finally, the correlation between running speed and dynamic levitation force is discussed. The investigation reveals that the levitation force experiences only a marginal decrease as the running speed increases. At a running speed of 240 km/h, the attenuation rate of the levitation force is approximately 2.478 %, demonstrating the commendable stability of HTS pinning maglev systems. The article concludes by presenting the dynamic levitation characteristics and their attenuation trends to speed. These findings can serve as valuable references for future design and practical implementation of HTS pinning maglev systems.