An Automatic HTS Flux Pump with Pulsed Voltage Drive

Flux pumps supply current to superconducting magnets without direct electrical contact, eliminating resistive leads and reducing their associated cryogenic load. Automatic flux pumps achieve this by periodically driving a section of the superconductor into the normal state by exceeding its critical current during part of the waveform cycle. Previously reported high-temperature superconductor (HTS) automatic flux pumps rely on bulky drive electronics and nonlinear current waveforms on the primary side for operation. In this work, we present an automatic HTS flux pump that simplifies these requirements by using a pulsed voltage waveform to drive the transformer primary. The system successfully charges an HTS magnet to 120 A dc within 20 s. It utilizes a noninductive bifilar HTS bridge as the self-rectifying element and a resistive copper braid as the transformer secondary. These results demonstrate how automatic flux pumps can be powered by simple dc sources, such as batteries, thereby improving the portability and practicality of HTS magnet power systems.