行波磁场中高温超导电动悬浮磁体的热性能研究

Study on the Thermal Performance of High-temperature Superconducting Electrodynamic Suspension Magnet Subjected to Travelling Magnetic Fields

地面线圈的交变磁场会在超导电动悬浮磁体中感应出涡流,产生涡流损耗,导致磁体温度上升。该文研究地面推进线圈产生的行波磁场对车载高温超导磁体热性能的影响,首先介绍高温超导磁体和推进线圈结构,分析行波磁场空间分布特征;搭建高温超导磁体热性能测试平台,测量行波磁场激扰下超导磁体内关键组件的温度分布,揭示各组件温度耦合关系;最后探究行波磁场频率和峰值对磁体温升的影响规律。结果表明,行波磁场激扰下,超导线圈的温升可忽略不计,但辐射屏温升显著,进一步使超导电流引线温度升高,增大电流引线失超风险,为此提出2种方法来限制电流引线温升。该研究成果可为高温超导悬浮磁体低温结构和电流引线的设计提供参考。

The thermal performance of high-temperature superconducting(HTS) electrodynamic suspension magnet is affected by the alternating magnetic fields from the ground coils due to the generation of eddy current losses. This paper aims at studying the thermal performance of the HTS electrodynamic suspension magnet subjected to travelling magnetic fields produced by the propulsion coils. First, the structures of the HTS magnet and propulsion coils are introduced, and then the spatial distribution of travelling magnetic fields is analyzed. Afterwards, an experiment platform is built to measure the thermal performance of HTS magnet, followed by the analyses regarding the effect of both the frequency and the amplitude of travelling magnetic fields on the thermal rise of the HTS magnet. It is demonstrated that, the travelling magnetic fields hardly affect the temperature of HTS coils inside the magnet, but significantly raise the temperature of HTS current leads, which will reduce the current-carrying capacity and possibly cause a quench on the HTS current leads. In this paper, two routes are proposed to restrict the thermal rise of HTS current leads. The insights attained by this study can provide useful implications for the design of the cryogenic system and HTS current leads of HTS suspension magnets.