Methods for Increasing the Saturation Current and Charging Speed of a Rotary HTS Flux-Pump to Charge the Field Coil of a Synchronous Motor

The rotary flux-pump using HTS tape has been studied for superconducting rotating machinery application. The charging speed and saturation current of the rotary HTS flux-pump is closely related to magnetic flux linkage passing through the HTS tape. To analyze charging parameters that effect pumping rate and saturation current of the flux-pump, methods of changing the rotating speed, shape of permanent magnet, width of HTS tape, and magnetic flux intensity have been investigated in previous studies [1]-[3]. In this paper, we have tried to test three cases to investigate the pumping rate and saturation current: 1) two different background materials, iron and Bakelite, were used to compare the magnetic flux linkage reinforcement; 2) two HTS tapes were overlapped to extend the magnetic flux linkage area, and each HTS tape was connected to an HTS coil; and 3) the parallel joint was conducted between the flux-pump and the HTS coil to compose a closed loop for persistent current mode. In order to measure the charging speed and pumping rate, a Hall sensor was installed at the center of the HTS coil.