Dynamic Properties of Magnetic Levitation System Using High-Temperature Superconductors

Pinning effect of a bulk high-temperature superconductor (HTS) has various possible applications, e.g., it enables a non-contact and stable levitation without active control. Regarding the magnetic levitation with HTSs, permanent magnets are generally employed, but our previous studies have demonstrated that the permanent magnets can be replaced with soft magnetic materials such as iron. When the magnetic levitation is applied to large transportation system, the use of this technique has a potential to allow a low-cost levitation system with a simple structure, in which expensive permanent magnets can be eliminated. In the mechanical design, a dynamic evaluation as well as a static evaluation must be needed. Hence, this paper fundamentally discusses dynamic properties of the magnetic levitation modulated by a damped harmonic oscillator model. For the dynamic analysis, this paper proposes a novel measurement method using repetitive control. The analysis shows that the dynamic properties of our system are related to the approach manner-process and speed-of the soft magnetic material to the HTS. It is expected that these results may shed further light on the design of efficient levitation system with HTSs.