高温超导块材磁体悬浮系统的振动特性

Vibration Characteristic of Magnetic Levitation System Using Bulk High-T_c Superconductor Magnet

指出了非直接场冷磁化产生的高温超导块材磁体在应用磁场中实现了稳定的悬浮或悬挂现象。利用Lakeshore公司的电磁铁和场控仪产生的均匀磁场作为磁化外场时,单块YBCO高温超导块材磁化率为77.8%,在应用外磁场下实现稳定悬浮的磁化外场区间仅为0.057～0.121T。为了验证高温超导块材磁体悬浮系统的稳定性,使用了一个随机信号形式的激励源,其幅值在0～14.5N之间且频率范围为0～400Hz。振动特性分析表明,高温超导块材磁体悬浮系统具有低频共振高频隔振性能;系统共振频率和动态刚度随着磁体俘获磁场的增大而增大;系统的阻尼系数表现出明显的先增后减的非线性特征。当超导磁体俘获磁场为0.091T时,即悬浮间距8mm,HTSMagnet-PM系统表现出最佳的动态特性,抗外界干扰能力最强。因此,这种非直接的场冷磁化方式产生的稳定悬浮现象,使得引入块材磁体成为了高温超导磁悬浮系统中可行的能量储备或改善系统稳定性的方法。

It is found that stable magnetic levitation （maglev） is realized by bulk high-Tc superconductor magnet （HTSCM） in the paper. Moreover, the way to magnetize bulk HTSCM is different from the usual field cooling magnetization. A homogenous magnetic field is used to magnetizate bulk YBCO HTSCM, which is produced by Lakeshore Electromagnet series and its controller. The magnetization ratio of a bulk YBCO is 77.8% in such the homogenous magnetization field. Stable system happens only at the magnetizing field range of 0.057 ～0.121 T. In order to evaluate the stability, the random force exciter is used with 1～400 Hz frequency range and 0 ～ 14.5 N amplitude range. By the further investigation, more vibration characteristics are found in the magnetic levitation system using bulk HTSCM. Resonance frequency is low while isolation frequency is high. Resonance frequency and dynamic stiffness increase with trapped magnetic field of bulk HTSCM, but damping coefficient shows nonlinear dependence. At the condition of 0.991 T trapped magnetic field and 8 mm levitation gap, the system shows its best dynamic property as well as the strongest anti-interference capability. Thus, to introduce bulk HTSCM can be feasible to improve dynamic stability and offer the more possible magnetic field energy.