Research On Characteristics Of High Temperature Superconductor Under Alternating Magnetic Fieeld And Structure Optimization Of Solenoid Magnet

It’s an important indices that the thermal stability of magnets that decides whether it’s safe and practical or not during running. As an important aspect of thermal stability, ac loss and heat transfer characteristics are problems worthy of studying. Due to expensive cost of raw materials, reducing the dosage of strip to improve the economic benefit becomes meaningful. Therefore, the numerical simulation on electromagnetic characteristics, temperature characteristics and ac loss of the YBCO high temperature superconductor (HTS) and structure optimal design to the three structure types of YBCO high temperature superconductor spiral tube magnet in this paper.First, this paper introduces the basic knowledge of superconductor and electromagnetic field analysis, the domestic and foreign research and application, the large-scale finite element analysis software Comsol and commonly used electromagnetic optimization algorithm in optimizing the structure of the superconducting magnet.Then, based on physical field coupling characteristics of Comsol, combined with the AC/DC module and heat conduction module, under different frequency and alternating magnetic field excitation, electromagnetic characteristic and temperature characteristic of the superconductor are simulated really-time under the condition of no external cooling and the ac loss in the process of operation is calculated to ensure safe and stabilization and avoid quench of superconductors.Finally, based on the advantages of solenoid coils that have simple structure, high material utilization and widely used, the nonlinear genetic algorithms that combines the capability of global search of genetic algorithm with local search ability strongly of nonlinear programming algorithm is used to optimize the structure of solenoid coils, making it a minimum of superconducting strip dosage to save the manufacturing cost of magnets in the case of satisfying certain constraints. And it provides certain guidance for the design of the superconductor in actual though analyzing and comparing the homogeneity and stray field distribution of diameter spherical volume (DSV)’s in before and after the structure optimization of superconducting magnet.