高温超导俘获场磁体充磁机理与充磁策略研究

High temperature superconducting (HTS) bulks and stacks of coated conductors can be magnetized to become trapped-field magnets that provide much stronger magnetic fields than those reachable with conventional permanent magnets. The trapped-field magnets are promising for a variety of electrical applications that use permanent magnets. The pulsed field magnetization (PFM) method is attracting attention as it can provide cost-effective, compact and flexible in situ magnetization for realizing practical applications of trapped-field magnets. The key challenge of PFM is that the produced trapped-fields are relatively low due to the temperature increase caused by fast flux motions..Targeting at this key problem, the project plans to measure and describe the temperature and magnetic field dependence and over-critical property of HTS tapes, to develop 2D and 3D electromagnetic-thermal coupled finite-element-method model for trapped-field magnets magnetized by PFM, to propose strategies to improve the trapped-field obtained by PFM, and finally to investigate the magnetization of HTS trapped-field magnets in practical applications. This project aims to investigate the flux dynamics during pulsed field magnetization of HTS trapped-field magnets, furthermore, to propose strategies to improve the trapped-field obtained by PFM.

高温超导块材或带材堆叠经充磁可用作俘获场磁体，提供远高于常规永磁体所能达到的磁场，应用超导俘获场磁体替代永磁体可大幅提高电工设备性能。脉冲充磁技术，因其能够对磁体进行经济、快速、灵活的充磁，是最终实现超导俘获场磁体工程应用的关键技术。然而脉冲充磁过程中，磁通快速运动引起大量发热，温度升高，使得获得的充磁磁场降低。.针对这一核心问题，项目拟在表征和描述高温超导带材电磁性质对温度和磁场的依赖性及其过流条件下的伏安特性基础上，开发描述俘获场磁体脉冲充磁过程的二维和三维动态电磁热耦合有限元仿真模型，从而提出能够有效提高充磁效率的优化策略，并进行系统实验验证，最终研究实际应用场景下的磁体充磁过程。项目目标实现对高温超导俘获场磁体充磁过程磁通动力学机理的系统研究，并得到优化充磁效果的策略。

高温超导俘获场磁体相对于线圈型高温超导磁体，优点在于不需要外接电源的持续供电，回避了常规超导磁体外接电源下整体装置笨重、电流引线漏热无法根除等问题；然而高温超导俘获场磁体相对于通电型超导磁体，成熟度较低，相关研究和方案较少。本研究围绕高温超导俘获场磁体的充磁基本机理、数值仿真、充磁方法和实际应用涉及的相关问题开展研究。主要成果有：通过实验与数值方法研究了过流条件下高温超导带材失超与恢复的特性，给出不同几何特征与带材可承认的冲击能量之间的关系；开发了可以快速准确仿真堆叠俘获场磁体脉冲充磁动态过程的三维模型，可将计算时间缩短一倍；通过30K和60K温度下的实验测量与有限元仿真，对比研究了常规堆叠磁体和电机中弯曲堆叠磁体的磁场特征，结果表明磁体弯曲不会造成磁场损失；以航空发电机为例对全超导和半超导型高温超导电机进行了概念设计与性能优化，并应用田口方法对电机的效率进行了优化。