An HTS NI Magnet Charged by Multiple Flux Pumps: Construction and Test of the Prototype

A high-temperature superconducting (HTS) no-insulation (NI) magnet charged by multiple flux pumps has been constructed and tested. The magnet consists of 5 NI double pancake coils (DPCs), whose inner diameter is 50 mm, outer diameter is about 92 mm, and the axial length of the NI magnet is 50 mm. To avoid the current limitation of single DPC on the whole magnet and fully use the current capacity of each DPC, the 5 DPCs were charged by 3 separate flux pumps to provide 3 different DC currents. The rotor speed of each flux pump was controlled by the LABVIEW program and microcontroller to regulate the charging current and the central magnetic field, which were measured by Hall sensors and displayed on the panel in real-time. The effect of the charging sequence on the central magnetic field had also been studied. Compared to the magnet operating at a single current, the proposed method in this paper has increased the central magnetic field from 290 mT to 390 mT, with an increase of 34.48%.