| High temperature superconductors have excellent physical properties such as high current carrying capacity and low loss.The high temperature superconducting tape prepared by high temperature superconductors is widely used in the field of electrical engineering and has become an important means to improve the performance of superconducting power equipment.Because superconducting power equipment often works in complex electromagnetic field environment,superconducting tape will inevitably be affected by alternating external electromagnetic field conditions and produce AC loss.The generation of AC loss will directly affect the operation stability and efficiency of superconducting equipment,increase the refrigeration cost of superconducting equipment,and restrict the development of superconducting power equipment.Therefore,the AC loss characteristics of HTS tapes under different external electromagnetic fields are studied and analyzed in this paper.Firstly,the paper summarizes the development of high-temperature superconductors and their applications,analyzes the research status of AC loss of superconductors at home and abroad,expounds the basic theory and mathematical model of superconductors,and summarizes the classification and calculation methods of AC loss of superconductors,which lays a theoretical foundation for the related research of AC loss in this paper.Secondly,according to the typical structure of the second generation commercial high temperature superconducting tape,the multi-layer structure superconducting tape model based on H formula method is established.Simultaneous interpreting and analyzing the transmission loss and magnetization loss under different transmission current conditions and external magnetic field conditions are carried out by finite element simulation.The results are compared with the simulation results and theoretical calculation results of the traditional superconducting thin film model,and the validity of the simulation model and its results is verified.Furthermore,the influencing factors and numerical variation rules of transmission loss and magnetization loss of single HTS tape under different external electromagnetic fields are obtained.Then,aiming at the typical stacking arrangement structure in engineering application,the paper constructs the finite element analysis model of stacking tape based on the single superconducting tape model,and carries out the finite element simulation calculation and analysis.The influence laws of the number of stacking layers and stacking spacing distance on the transmission loss and magnetization loss are explored respectively.By analyzing the distribution of electromagnetic field,the main influencing factors and loss variation law of stacking tape loss are obtained.In addition,the dependence of stacked tapes on different external electromagnetic field conditions is simulated and compared with the dependence of single tape loss,and the differences between them are summarized.Finally,the loss characteristic test platform of superconducting tape is built,and the AC loss value of superconducting tape under different working conditions is tested according to the electrical measurement method.By comparing the experimental data,finite element analysis results and theoretical calculation results,the main research contents and conclusions of this paper are verified,which lays a foundation for the further study of AC loss of high temperature superconducting materials,and provides a theoretical basis and practical reference for reducing AC loss,reducing refrigeration cost and improving equipment efficiency of superconducting power equipment. |
