共查询到18条相似文献,搜索用时 125 毫秒
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临界电流值是描述Bi2223高温超导带材性能的一个基本参数,在一定的温度条件下,Bi2223高温超导带材的临界电流是带材所在位置磁场大小和磁场方向的函数,其短样的临界电流值可以通过四引线法测量,单根超导带材的自场很小,磁场对临界电流的影响可以忽略.高温超导磁体的临界电流被定义成引发该磁体失超的最小电流,高温超导磁体的自场比单根超导带材的自场要大得多,磁体各个位置的磁场大小和方向各不相同,很难用理论的方法准确计算磁体的临界电流.对于高温超导磁体而言,除了磁场的影响因素以外,绕制磁体所用的超导带材自身的均匀性也是影响其临界电流的一个重要因素.本文对这两个因素进行探讨,并着重讨论高温超导带材自身的均匀性对临界电流大小的影响,本文的结论可以为高温超导磁体的设计、磁体绕制时带材的选择、磁体运行时安全工作电流的确定提供帮助. 相似文献
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第二代高温超导带材与第一代相比,有着载流能力强、交流损耗低、无需贵金属等优点,在超导电力应用中有广阔前景。高温超导带材临界电流在外磁场的影响下会发生衰减,超导带材临界电流的角度依赖性是超导电力装备设计必不可少的参数。实验选取温度50~77 K、磁场0~3.5 T、磁场角度0~360°区间,分别测量了上海超导、苏州新材料等厂家生产的市面主流第二代高温超导带材的临界电流,分析了不同背景磁场大小及角度下超导带材的各向异性。结果表明,各厂家生产的超导带材具有明显的各向异性。 相似文献
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高温超导变压器的漏磁场降低绕组中的临界电流并增加交流损耗;超导材料的零电阻特性使得绕组限制环流的能力极低.因此,在设计超导变压器时,进行磁场分析和环流计算显得尤其重要.本文采用场-路结合的方法,即在用ANSYS求得反映变压器各支路之间电磁耦合的电感矩阵的基础上列出电路方程,计算了变压器低压绕组5种不同形式的各支路电流分布,并进而分析了磁场.同时提出了减小环流和改善磁场分布的一些措施. 相似文献
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The critical current of high-temperature superconductor (HTS) tapes depends on temperature, magnetic field, and flux angle against the tape. Analyzing the performance of an HTS coil relies on the critical current equation, which has these dependencies. To date, the critical current equation has been obtained by fitting the measured data. However, this fitting method requires the time-consuming and laborious work of measuring the tapes. In this study, based on a new transition concept in applying a magnetic field, we show how to obtain the critical current equation, while keeping the temperature constant. From the wave function of the Cooper pair which distributes along a magnetic flux quantum, a wave function at the transition state is obtained; this yields the wave functions with perpendicular and parallel magnetic components against the tape. Combining these wave functions yields the conclusive critical current density equation. To confirm the accuracy of this equation, used Bi-2223/Ag tapes, it was compared with the measured critical current under various magnetic fields and flux angles; it was found that they agree well. The parameters of this equation can be obtained by measuring the perpendicular/parallel critical magnetic field component. This equation does not require fitting the measured data, therefore, it can be employed with any Bi-2223/Ag tape. 相似文献
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高温超导磁体临界电流磁矢量分析法准确地预测了BSCCO高温超导磁体的临界电流,为了进一步验证该方法预测YBCO高温超导磁体临界电流的准确性,文中作者用9.3m二代高温超导YBCO带材绕制了一个内径为70mm,外径为100mm,共35匝的单饼,测试了单饼5-15匝,15-25匝,25-35匝和5-35匝在77K下的临界电流,并用磁矢量分析法进行了仿真分析。通过对比发现,仿真分析和实验结果的误差在5%左右,最大误差是6.75%,最小误差是4.77%,验证了磁矢量分析法在预测YBCO高温超导磁体临界电流时的准确性。 相似文献
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超导带材应用于超导电力设备时,其临界电流特性受外界交变磁场大小和方向的影响,展现出明显的各向异性.为了减小外场对超导带材的影响,本文通过窄丝化工艺将4 mm宽的高温超导带材分切成2 mm宽的高温超导细丝.本文通过冷热循环疲劳测试实验和带材显微观察两个角度相互验证,对2 mm超导细丝临界电流性能做了具体评估.创新性地提出"在窄丝化工艺中引入电镀铜工艺作为过渡来改善超导细丝临界电流特性",通过实验以及显微观察证实"电镀铜工艺能够在超导细丝表面生成铜保护层,有效降低超导细丝临界电流的衰减".本文也为后续超导细丝在复合结构的应用中提供了重要参考. 相似文献
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Shinichi Ishiguri Taisuke Funamoto 《Physica C: Superconductivity and its Applications》2011,471(11-12):333-337
In this paper, we establish a model to analyze the transport current performance of a high-temperature superconducting (HTS) coil, considering the dependencies of critical current and n-value of an HTS tape on magnetic field and magnetic field angles. This analysis shows that relatively large electric fields appear at the coil’s edges, preventing improvement in the transport current performance of the coil. To solve this problem, in this paper, we propose a graded coil in which several coil edges of different heights are separated and graded. Analysis of its performance shows that the coil’s critical current increases, thus confirming that there exists an optimum coil cross section at which the stored energy and central magnetic field improve 2.1 times and 45%, respectively, compared with a typical rectangular coil that employs the same total length of the HTS tape. It is recommended that these results of the coil should be applied to SMES. 相似文献
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基于Bean临界态模型,针对目前的高温超导磁悬浮车系统,提出了一种模拟计算方法,该方法可计算在时变外磁场中块材导向力的衰减变化情况。通过对时变外磁场中块材温度、俘获磁通以及导向力等参数变化情况的实验结果和计算结果的对比,证实了该模拟计算方法的有效性。该模拟计算方法可用于定性研究高温超导块材的导向力性能在时变外磁场作用下的变化情况,为高温超导磁悬浮车的研究和工程实践提供了较为重要的科学依据。 相似文献
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基于Kim临界态模型,通过考虑超导块材内部屏蔽电流的穿透历史过程,讨论了场冷条件下临界电流密度对高温超导悬浮系统磁悬浮排斥力和吸引力的影响.结果显示:最大超导磁悬浮排斥力和吸引力均随临界电流密度的增加呈指数关系增加,并趋于饱和;场冷条件下的磁悬浮力回滞能量损耗远高于零场冷情况;存在一个磁悬浮力比率κ,κ值对于评价大电流... 相似文献