NdFeB永磁轨道上方YBaCuO块材的悬浮稳定性与场冷位置间关系

如何获得稳定悬浮是高温超导磁悬浮系统的一个重大问题.高温超导体在外磁场中所受的悬浮力和导向力是两个衡量系统悬浮稳定性的重要参数.本文实验研究了场冷情况下NdFeB永磁轨道上方YBaCuO块材在竖直运动和水平运动时所受悬浮力和导向力的情况,并且根据Bean模型开发了数值计算程序用于悬浮力和导向力的计算分析.不同竖直场冷高度下计算值和实验值获得了较好的一致性.实验结果和计算结果都显示出永磁轨道场中高温超导体所受的两个力与其场冷历史有着密切的关系,也就是说超导体的悬浮稳定性受场冷历史影响程度较大.不同的竖直场冷高度,其最大悬浮力的变化趋势和最大导向力的变化趋势相反.较小的水平场冷位置导致了较大的导向力和较大的磁滞.根据上述结果,为了获得较优的悬浮稳定性,本文推荐了可行的场冷高度范围和有效的高温超导体组合方式.

DEPENDENCE OF LEVITATION STABILITY OF THE YBaCuO BULK ABOVE A NdFeB GUIDEWAY ON FIELD-COOLED POSITION

For the high temperature superconductor (HTS) Maglev system, it is a key problem to realize stable levitation. Levitation force and guidance force of HTS bulks in applied field are two primary parameters. These two forces of YBaCuO HTS bulk above a NdFeB permanent magnetic guideway (PMG) is investigated in the field-cooled (FC). And codes were developed based on the Bean model to calculate these two forces. At different vertical FC positions, the calculation agrees with the experiments well. The results suggest that both forces are also strongly dependent on the HTS cooling history over the PMG, that is to say, HTS cooling history has great influence on levitation stability. For vertical FC positions, the trend of the maximum levitation force is contrary to that of the maximum guidance force. For smaller horizontal FC positions, the guidance force is larger and the hysteresis is stronger. An avail FCH and an effective bulks array mode are also proposed for better levitation stability according to the above results.