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本论文对高温超导磁体在传输直流电流时产生的损耗进行了理论分析和实验验证.本文考虑了高温超导带材非线性模型磁场方向对带材临界电流和n值的影响,用Bi2223超导带材绕制了(一个由20个双饼组成的高温超导磁体,用数值仿真和实验方法研究了此磁体传输直流电流时的指数损耗.并对每个双饼以及每匝线圈的损耗进行了分析.在液氮温度下对一个双饼线圈进行了指数损耗的测量,测量结果与数值仿真结果相当吻合.利用高温超导体临界电流此非线性模型,本文对此磁体快速励磁情况下的交流损耗的特点进行了数值模拟. 相似文献
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本论文对高温超导磁体在传输直流电流时产生的损耗进行了理论分析和实验验证.本文考虑了高温超导带材非线性模型磁场方向对带材临界电流和n值的影响,用Bi2223超导带材绕制了(一个由20个双饼组成的高温超导磁体,用数值仿真和实验方法研究了此磁体传输直流电流时的指数损耗.并对每个双饼以及每匝线圈的损耗进行了分析.在液氮温度下对一个双饼线圈进行了指数损耗的测量,测量结果与数值仿真结果相当吻合.利用高温超导体临界电流此非线性模型,本文对此磁体快速励磁情况下的交流损耗的特点进行了数值模拟. 相似文献
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《低温物理学报》2015,(5)
高温超导带材的各向异性特性一直影响着它工程使用中性能的充分发挥,为了提高带材的利用率,本文提出了一种基于阶梯电流的优化方法,利用MATLAB对YBCO高温超导储能单螺管磁体的结构进行优化获得初步模型,对双饼线圈进行分组,以两阶梯电流和三阶梯电流为例对磁体进行了优化.分析了各组双饼线圈的磁场分布和临界电流,计算了各部分带材性能的利用率.利用有限元软件分析阶梯电流引起的磁场变化,在充分考虑带材的临界特性和各向异性的前提下优化各组线圈的电流大小.仿真计算表明,和统一电流磁体相比,采用阶梯电流法能够优化磁体磁场构型,提高平均储能密度,最终提高磁体带材的利用率从而提升储能.阶梯电流法同样适用于多螺管磁体,对于超导储能磁体的优化是一种行之有效的方法. 相似文献
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《低温物理学报》2016,(2)
高温超导储能磁体(HTS-SMES)是电力系统中的重要应用.文中设计了一种0.5MJ级SMES装置,采用YBCO高温超导带材绕制为14组线圈饼,每组线圈饼由四个单饼线圈组成,设计工作温度为20K,工作电流100A.SMES装置在运行时,中心磁场接近3T,保证高磁场下YBCO带材的临界电流是SMES装置正常运行的必要条件.文中通过有限元的方法分析了运行工况下SMES装置的漏磁场,线圈内磁感应强度的分布,在该磁场条件下带材性能满足运行条件.通过电磁,结构耦合计算与冷却过程的应力分析,得到了线圈上的米塞斯应力与形变,满足储能磁体运行的条件,可以为SMES装置的设计和运行提供参考. 相似文献
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超导磁体的场强与超导材料的载流能力、磁体口径和低温环境有密切关系.为了在中高温区域实现高磁场强度的超导磁体,采用国产第二代高温超导带材,成功绕制出内直径为100 mm的高温超导线圈.该超导线圈在77,65,55和46 K不同温区下进行了性能测试,其最大运行电流分别为65,147,257和338 A,对应的中心磁场强度分别为0.78,1.77,3.1和4.08 T.所研制的超导线圈的中平面上磁场基本一致. 相似文献
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Jozef Pitel Pavol Kováč 《Physica C: Superconductivity and its Applications》2011,471(23-24):1680-1688
A computational model which enables to evaluate the distribution of the critical currents, electric fields and the voltage in the winding of a solenoidal high temperature superconducting (HTS) magnets subjected to an external magnetic field parallel with the magnet axis, was developed. The model comes out from the well-known power law between the electric field and the transport current of the HTS tape short sample. It allows to predict the voltage–current V(I) characteristics of both the pancake coils and the complete magnet. The model was applied to the magnet system consisting of 22 pancake coils made of multifilamentary Bi(2223)/Ag tape at 20 K, which is subjected to an external uniform magnetic field parallel with the coil axis. A rather unexpected behavior of the magnet at different operating conditions (operating current and external magnetic field strength) is predicted, analyzed and reported together with a theoretical explanation. On one hand, the external uniform magnetic field parallel with the coil axis increases the resulting magnetic field strength, however, on the other hand it simultaneously decreases the angle between the resulting magnetic field and the tape surface. Thus, the effect of higher magnetic loading caused by the presence of an external magnetic field strength which is acting on individual turns located close to the coil’s flanges is compensated by more favorable orientation of the tape with respect to the resulting magnetic field. As a result, increase in the critical currents of these turns is expected. Further, the results indicate, that in case of the high field HTS insert coils the anisotropy in the Ic(B) characteristic does not play a substantial role. As a consequence, the technology of the production of the tapes for high field insert HTS coils should concentrate rather on the tapes having the current carrying capacity as high as possible, than on the attempt how to decrease the anisotropy in the Ic(B) by changing the architecture of the filaments in the tape. 相似文献
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It is necessary to develop HTS conductors with a large current capacity and low AC loss characteristics for practical use of HTS power devices. For large capacity power applications, HTS tapes such as Bi-2223 tapes and YBCO coated conductors are assembled. So, it is important to evaluate the characteristics of current distributions in such assembled HTS tapes. However, an adequate measurement method has not been established. In this study, we have tried the development of an indirect measurement method to evaluate the current distributions in stacked HTS tapes. In this method, the current distributions are indirectly found from the results of the field distributions measured by a pickup coil located around the surface of the sample tapes. To confirm the accuracy and the sensitivity of this method, current distributions in a test conductor made of copper tapes are measured. Numerical and measured current distributions are compared. Using this method, the current distributions in stacked Bi-2223 tapes are measured at room temperature and 77 K. On the basis of the obtained results, the characteristics of the AC current distributions in the HTS tapes are discussed. 相似文献
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本给出了三种提高YBCO块材在外磁场中悬浮力的方法.第一种方法是增强外磁场,对于此方法,本研究了一块直径为30mm的圆柱状YBCO块材分别在圆柱状NdFeB永磁体和NdFeB永磁导轨上的悬浮力.测量结果表明在77K温度下YBCO块在圆柱状NdFeB永磁体上的最大悬浮力为50N,在NdFeB永磁导轨上的最大悬浮力为103.ON.第二种方法是提高YBCO块材自身的性能,包括临界电流密度、俘获磁通和块材尺寸,对于此方法,本仅研究了块材尺寸对悬浮力的影响.三块直径分别为30mm、35mm、40mm的圆柱状YBC0块材在NdFeB永磁导轨上的悬浮力被测量,77K温度下5mm悬浮间距时的悬浮力分别为103.ON、134.5N、175.ON.第三方法是将YBCO块材变成准永久磁体,此种情况下,直径为40mm的圆柱状YBCO块材在77K温度下5mm悬浮间距时的悬浮力高达218.3N. 相似文献
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本文阐述了几种优化方法及其对它们的改进,并选用测试函数对各种方法的寻优性能作了对比;然后阐述了高温超导磁体的径向磁场对临界电流的影响及最大径向磁场的位置定标方法;最后将各种优化方法应用于高温超导磁体的设计中.经过优化,高温超导磁体大大减小了其体积,提高了超导材料的利用率,节约了超导材料的用量及制冷时所损耗的电源功率. 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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中国科学院高能物理研究所正在进行环形正负电子对撞机-超级质子对撞机(CEPC-SPPC)的研究工作,未来超级质子对撞机(SPPC)初期要求的主环二极磁体磁场强度为12 T,升级后的磁体场强需求为20~24 T.为了达到15 T及以上的场强,高温超导线材制作的内插高场线圈是目前的唯一选择.本文对YBCO内插线圈做了相应的探究,并提出的一种新的设计方案,具有以下特点:线圈结构采用Common-coil与Block-type混合的设计,并解决了端部弯曲半径小的问题;充分利用YBCO在高场下磁场与超导带材平行时临界电流密度是垂直情况下的数倍特性,通过优化端部结构减小线材与磁场夹角;计算了不同形状及弯曲半径组合下的线材弯曲情况,综合考虑了端部长度与线材张力之间相互制约的问题,并给出了最终结果;试绕了两种端部的铜线圈,以及balloon-end的高温超导YBCO线圈并进行了测试. 相似文献
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It is thought that the design of magnetic field modulation coils is one of the factors limiting enlargement of the sample
size in electron paramagnetic resonance (EPR) measurements. In this study, we miniaturized the magnetic field modulation coil
and combined it with a surface-coil-type resonator (SCR). The inductor of the SCR was a circular single-turn one-loop coil
(diameter, 1 mm), and the magnetic field modulation coil was a twin-loop coil consisting of two solenoid coils each made of
15 turns of copper wire on a cylindrical bobbin with an axial length of 3 mm and an elliptical cross section (major axis,
7 mm; minor axis, 3 mm). The former was located on the latter via a spacer (thickness, 3 mm) in such a way that the directions
of their axes coincided. Their combined size was about 10 mm wide, 10 mm deep, and 6 mm high. The transmission lines of the
SCR were set on resonance at about 700 MHz. EPR measurements of a phantom (comprising agar that included a nitroxide radical
and physiological saline solution), made with a miniaturized modulation coil combined with the SCR, exhibited a sensitivity
similar to that for the conventional method.
Authors' address: Hidekatsu Yokoyama, Department of Pharmaceutical Sciences, International University of Health and Welfare,
2600-1 Kitakanemaru, Ohtawara 324-8501, Japan 相似文献