Characteristics of Pumping Current in a YBCO Coil by a Pulse-Type Magnetic Flux Pump

Abstract

2G high-temperature superconducting (HTS) wires and YBCO-coated conductors perform better carrying current capability, which is potentially applied to the manufacture of HTS magnets. This article 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 (LN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) cryogenic environment. The 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. The excitation effects of the YBCO coil at different temperatures were investigated in the conduction-cooling system. A fast increase of pumping current in the YBCO coil occurs when the temperature of the YBCO sheet (i.e., pumping bridge) is in the range of 50-80 K. The relationships among the 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 LN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> cooling system show the possibility of the pulse-type magnetic flux pump for the practical application of HTS magnets.