Trapped Field Characteristic of YBCO Bulk in AC External Magnetic Field
Trapped Field Characteristic of YBCO Bulk in AC External Magnetic Field
复制标题
YBCO块体在交流外磁场中的俘获场特性
DOI：
10.1541/ieejpes.124.1357
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
T. Morisaki
中科院分区：
文献类型：
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作者：
H. Ueda;A. Ishiyama;T. Morisaki
俘获场特性是高温超导体在磁悬浮系统、电机、体磁铁等领域应用的关键因素之一。作为准永磁体的超导体应用需要恒定的俘获场，但在实际的电气设备运行环境中，俘获场会受到时变外磁场的影响和改变。这意味着随时间变化的磁场改变了体内的屏蔽电流分布，瞬态磁通运动导致温度升高，最终导致捕获场减小。在本研究中，我们观察到在频率高达50 Hz的范围内，外部交流磁场的捕获场突然减小。并利用新开发的基于有限元法（FEM）的计算机程序进行了数值模拟。在仿真程序中，考虑了依赖于不可逆温度的电压-电流（E-J）特性。从这些结果可以认为，捕获场的突然减小是由于交流损耗引起的温度升高引起的。
Trapped field characteristics are one of the key factors in the application of high-temperature superconducting bulk, such as magnetic levitation systems, motors, bulk magnets and so on. The immutable trapped field is required in superconducting bulk applications as a quasi-permanent magnet, however, the trapped field is influenced and changed by a time-varying external magnetic field in a realistic operational environment of electrical devices. This means that shielding current distribution within the bulk is changed by the time-varying magnetic field and the transient magnetic flux movement results in temperature rise and finally reduction of the trapped field. In this study, we observed the abrupt reduction of the trapped field for the external AC magnetic field in the range of frequency up to 50 Hz. And we also performed the numerical simulation using a newly developed computer program based on the finite element method (FEM). In the simulation program, the voltage-current (E–J) characteristics, which depend on the irreversibility temperature are taken into account. From these results, it can be considered that the abrupt reduction of the trapped field is caused by the temperature rise due to AC loss.