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题名	高温超导永磁体组合问题的研究; 高温超导永磁体组合问题的研究
作者	1王琰,电工研究所
学位类别	工学硕士
答辩日期	1998
授予单位	中国科学院电工研究所
导师	1林良真,电工研究所
关键词	高温超导体 永磁体 组合问题 磁通蠕动 等效电流模型 脉冲磁化 有限元法 YBCO HTSC Permanent Magnet Combination Problem Flux Creep Equivalent Current Model Pulsing Magnetization Finite Element Method
其他题名	高温超导永磁体组合问题的研究
学位专业	超导技术及磁流体发电
中文摘要	实验发现HTSC样品组合的“增效效应”，即两块样品的叠加俘获磁场比单块样品磁场的代数和略大。组合方式影响钉扎磁通的蠕动率，磁通衰减的减慢导致了所谓“增效效应”。磁体组合影响到高温超导永磁体磁通钉扎与蠕动的动态过程，而在稳衡态下仍满足磁场的线性叠加性。由电流密度与磁场的线性性可降低组合设计中的复杂性。分析了高温超导材料与稀土永磁材料微观磁通结构的异同点，比较高温超导永磁体的俘获磁通性质与常规稀土永磁体的相似点。实验测试了YBCO块材样品ab和c方向的钉扎磁场。强各向异性表现了为磁矩有c轴择优取向特性，超导电流具有准二维特征。提出计算HTSC钉扎磁场的等效电流模型，磁场由二维等效体电流与面电流产生。模型计算与磁场俘获实验和磁浮力实验测试结果进行了比较。该模型的简洁实用性有利于工程设计。对YBCO 永磁材料做了毫秒级脉冲磁化效果的实验研究。毫秒级脉冲场磁化可减小磁通衰减率。脉冲场的幅值和宽度对磁化效果有显著影响，一定温度和脉宽下，脉冲场存在一定的幅值范围使得磁化效果最佳。脉冲持续时间的加长有利于磁体钉扎磁场达到饱和，但以加大充磁设备损耗、降低充磁机效率为代价。材料形状、尺寸影响磁化效果，定性计算表明样品电磁参数直接影响电磁脉冲在高温超导体内的传播与衰减。在等效电流模型的基础上，用有限元法计算分析了软磁介质的加入对HTS组合磁体空间磁场分布的影响。进行了稀土永磁体与高温超导永磁体磁路设计的对比，其相似性使得HTS永磁体系统可以借鉴常规永磁体系统的设计方法。 HTS块材最大磁浮力、饱和磁场和临界电流密度的一一对应关系，提出HTS组合磁体的工程设计方法。与螺线管线圈作类比，可分析计算磁体系统的磁场和电磁作用力。 Synergistic effect is detected in experiments of High Temperature Superconducting Permanent Magnet (HTS-PM), i.e., the trapped field within two pellets are slightly larger than the mathematical sum of individual ones. Investigation shows combination modes influence the creep rate. The slackened flux decay in combined magnets results in the synergistic effect. Combination casts effects on dynamics of flux, while at equilibrium linear summation is still applicable in combined magnetic fields. The linearity could simplify the design of HTS-PM. Similarities between HTS-PM and Rear Earth Permanent Magnet (RE-PM) are studied. Anisotropy of trapped fields is studied experimentally. Highly anisotropy makes magnetic moment have preferred orientation of c-axis and supercurrent is quasi-two dimensional. A macroscopic Equivalent Current Model (ECM) is proposed to describe the tapped field. The flux density and levitation forces are measured to testify. The utility could be helpful in engineering. Magnetization effect by Pulse Field (PF), which has the width of millisecond, is experimentally investigated. Creep rate is significantly reduced by RF. Under certain condition such as temperature and pulse width, there is an optimal magnitude of RF for HTS bulk to trapped maximal field density. Bulks are apt to reach the saturated state when magnetized by long duration pulses at the expenses of the efficiency of magnetizer. The magnetization effect is also determined by bulks' dimensions and materials' electromagnetic parameters. Finite Element Method (FEM) is employed in analyzing the influence of soft magnetic material on magnetic field of HTS-PM. The magnetic circuits could be designed by the methods of RE-PM similarly.A designing method is proposed according to the one-to-one correspondence among the maximal levitation force, the saturated field density and critical current density. Comparable to solenoid, magnetic field and electromagnetic forces of HTS-PM could be calculated.
语种	中文
公开日期	2010-10-18
页码	59
内容类型	学位论文
源URL	[http://ir.iee.ac.cn/handle/311042/7621]
专题	电工研究所_其他部门_其他部门_硕士学位论文
推荐引用方式 GB/T 7714	1王琰,电工研究所. 高温超导永磁体组合问题的研究, 高温超导永磁体组合问题的研究[D]. 中国科学院电工研究所. 1998.

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