Experimental Electromagnetic Characterization of High Temperature Superconductors Coils Located in Proximity to Electromagnetically Active Materials

The electromagnetic properties of high temperature superconductors(HTS)are characterized with the explicit intent to improve their integration in electric power systems.A tape and a coil made of Bismuth Strontium Calcium Copper Oxide(BSCCO)are considered in the presence of electromagnetically active materials in order to mimic properly the electromagnetic environment typical of electrical machines.The characterization consists of the determining the critical current and the AC losses at different values of the frequency and the transport current.The effects induced by the proximity of the active materials are studied and some related experimental issues are analyzedc.

高温超导YBCO线圈交流损耗的频率特性

YBCO线圈的交流损耗直接关系到YBCO设备的运行成本及稳定性。实现对YBCO线圈交流损耗的快速、准确测量,对于开展YBCO涂层导体的应用研究具有重要的意义。文中采用电测量法,在77K、零场和不同频率条件下,对YBCO线圈通以不同运行电流时产生的交流传输损耗进行测量。构建了YBCO线圈交流损耗的数值计算模型,对YBCO线圈交流损耗进行理论研究,最后将实验数据与理论计算结果进行比较,两者结果基本一致。可以发现,YBCO线圈在频率低于75Hz时,交流传输损耗随频率的增大而减小,当频率从75Hz增加到195Hz时,交流传输损耗随频率的增大而增加。

Behavior of a superconducting bulk in a running high-T_c superconducting maglev system(I):distribution of magnetic and electric field

A theoretical model of describing the electromagnetic and thermal dynamics of high-Tc superconducting bulks in a high-Tc superconducting Maglev system is built up.The model contains the effects of hysteresis-type loss,flux flow,flux creep,and thermal diffusion on the superconducting bulks in the Maglev system.As the first stage of this study,the behavior of magnetic and electric fields,as well as the distribution energy flow density in the superconducting bulk is studied.The results show that the flux flow and thermal diffusion affect the behaviors of the electromagnetic field in the high-Tc superconducting bulks in different ways;however,both of them contribute significantly to the energy dissipation of the superconducting bulks when they are used in the Maglev train.

高温超导YBCO线圈交流损耗实验研究与分析

交流损耗是高温超导YBCO线圈设计的一个重要参数,直接关系到高温超导装置的运行成本和稳定性。文中利用热测法实现对高温超导YBCO线圈交流损耗的准确测量,并给出了高温超导YBCO线圈的理论数值计算模型,通过理论计算值与实验结果的比较分析,两者结果基本相符。研究结果为开展1MJ高温超导储能-限流磁体的研制具有十分重要的指导意义。

YBCO线圈交流损耗的有限元分析与实验验证

随着高温超导YBCO带材载流能力的不断提高和成本的逐渐降低,YBCO线圈及磁体的应用将日益广泛。文中利用有限元方法研究了YBCO线圈的交流损耗特性,计算了50Hz下线圈的瞬时交流损耗,分析了每匝带材中的电流和磁场分布。仿真结果表明,线圈内侧承受的磁场最大,但线圈中部每周期的交流损耗最大,且线圈中始终存在未被磁场穿透的区域。除此之外,文中实验测量了YBCO线圈的临界电流和交流损耗,实验结果良好地验证了仿真方法的正确性。

用于超导脉冲变压器的双饼线圈交流损耗优化

基于二维轴对称H方程法对用于高温超导脉冲变压器的YBCO双饼线圈进行了有限元建模与仿真,研究了分磁环参数和开槽数对YBCO双饼线圈传输原边电流时的磁场特性和交流损耗的影响。仿真结果表明,分磁环能够显著减弱双饼线圈的径向磁场,降低其交流损耗。对分磁环开槽后,径向磁场主要分布在开槽处。当分磁环相对磁导率为100,与线圈间距为0.25 mm,厚度为1 mm,开槽数为3时,双饼线圈交流损耗降低了64.9%。