Characteristics of Pumping Current in a YBCO Coil by a Pulse-Type Magnetic Flux Pump
2G high temperature superconducting (HTS) wires, YBCO coated conductors, perform a better carrying current capability, which is potentially applied in the manufacture of HTS magnets. This paper presents the experimental results of the pumping current for YBCO coils using a pulse-type magnetic flux pump in the conduction-cooling system and liquid nitrogen bath (LN2) cryogenic environment. Optimization of the flux pump used in the conduction-cooling system is that a constantan heater was added to keep the temperature of the pumping bridge at a certain value. Excitation effects of the YBCO coil at different temperatures were investigated in the conduction-cooling system. A fast-increasing of pumping current in the YBCO coil occurs when the temperature of the YBCO sheet (i.e., pumping bridge) is in the range of 50 K to 80 K. The relationships between saturated pumping current and input voltage, working frequency, numbers of magnetic poles were also studied. Using the seven-pole configuration, the saturated current can reach 155 A when the frequency is 20 Hz and the voltage is 6 V. The excitation characteristics of the flux pump in the LN2 cooling system show the possibility of the pulse-type magnetic flux pump for the practical application of HTS magnets.