A kilo-Ampere level HTS flux pump

TL;DR

This paper introduces a high-current HTS flux pump capable of over 1.1 kA at 77 K, significantly advancing high-field magnet applications by reducing size, cost, and improving flux injection accuracy.

Contribution

The development of a compact, high-current HTS flux pump that achieves the highest reported operating current and demonstrates potential for ultra-high field magnet operation.

Findings

Achieved quasi-persistent current over 1.1 kA at 77 K.

Maintained flux ripple below 0.2 mili-Weber at high current.

Reduced device size compared to traditional power supplies.

Abstract

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