Stiffness characteristic of HTS pinning maglev system with electromagnetic compensation device

Abstract

The high-temperature superconducting (HTS) pinning magnet levitation (maglev) train, with its unique self-stabilizing and levitation-guidance integration, holds great potential for high-speed transportation. The levitation stiffness between the train and permanent magnet guideway (PMG) is crucial for studying HTS maglev dynamics and vibration reduction design. However, the magnetic hysteresis characteristics of HTS bulk can alter levitation stiffness. During high-speed operation, the high-frequency magnetic field excitation from PMG induces eddy current losses in the HTS bulk, reducing levitation force and levitation stiffness, thereby compromising train safety and increasing vibrations. Therefore, this paper investigates the HTS maglev system with an electromagnetic compensation (EMC) device to compensate for this loss, measuring and analyzing its levitation stiffness. First, a quasi-static stiffness experiment was designed to analyze and summarize the variation of levitation stiffness under different current intensities. Second, based on the experimental results, a vertical motion model was proposed and validated using the Lyapunov method. Then, dynamic experiments were designed to analyze the dynamic response of the system at different frequencies. Finally, the model simulations were combined with dynamic experiments to analyze the phenomena and dynamic characteristics of levitation stiffness changes in the system. This paper shows that the EMC device can effectively enhance levitation stiffness and improve the stability of the system under high-frequency vibrations. The levitation stiffness characteristics proposed in this study can provide relevant references for subsequent stiffness optimization and shock absorber design.