Characterization of HTS Bifilar Bridge for Self-Regulating Flux Pump: Experimental and Numerical Study

Self-regulating high-temperature superconducting (HTS) flux pumps offer a promising solution for compensating the magnetic field degradation in closed HTS coils without direct electrical contacts. These flux pumps utilize superconducting bridges, which function as switches based on their nonlinear resistance. This study focuses on evaluating and analyzing the charging performance of a bifilar bridge coil wound with various insulated coated conductors. The V-I curves of these tapes are measured across a wide range, highlighting the occurrence of current sharing beyond the critical current. Furthermore, a full-scale finite element model is developed to investigate the current variation within multilayer tapes during the charging process and elucidate the underlying noninductive principle. The findings reveal remarkable disparities in the charging characteristics of REBCO conductors with different widths and thicknesses as bridge materials, which will significantly impact the charging function of flux pumps. This research provides valuable insights for optimizing the design of self-regulating flux pump.