A kilo-ampere level HTS flux pump

Abstract

This paper reports a newly developed high current transformer-rectifier\nHigh-Tc Superconducting (HTS) flux pump switched by dynamic resistance. A\nquasi-persistent current of over 1.1 kA has been achieved at 77 K using the\ndevice, which is the highest reported operating current by any HTS flux pumps\nto date. The size of the device is much smaller than traditional current leads\nand power supplies at the same current level. Parallel YBCO coated conductors\nare used in the transformer secondary winding as well as in the superconducting\nload coil to achieve high current. The output current is limited by the\ncritical current of the load rather than the flux pump itself. Moreover, at\nover 1 kA current level, the device can maintain high flux injection accuracy,\nand the overall flux ripple is less than 0.2 mili-Weber. The work has shown the\npotential of using the device to operate high field HTS magnets in ultra-high\nquasi-persistent current mode, thus substantially reducing the inductance,\nsize, weight, and cost of high field magnets, making them more accessible. It\nalso indicates that the device is promising for powering HTS NMR/MRI magnets,\nin which the requirement for magnetic field satiability is demanding.\n