Charging Optimization of a YBCO Racetrack Coil With a Linear-Motor Type Flux Pump for an HTS Synchronous Motor

This paper presents the preliminary charging test results of an high temperature superconducting (HTS) no-insulated (NI) double racetrack coil with the linear-motor type flux pump. The racetrack coil is designed and manufactured for the rotor field winding of a 16.9-kW-class HTS synchronous motor. This HTS synchronous motor was designed to employ a contactless static excitation device (CSED), i.e., the linear-motor type flux pump, which can charge the racetrack coil installed in the rotating machine in contactless manner. In the experiment, the major components of the 16.9-kW-class HTS synchronous motor, such as the racetrack coil and the CSED, had been manufactured, tested and optimized. The charging performance was tested in 77 K. In particular, we optimize the CSED of the HTS synchronous motor by testing different wavelengths of flux pumps and different superconducting stator wires, so as to select the appropriate wavelength of the flux pump and stator wire to optimize the operation of the synchronous motor.