Test of Two Kilo-Amp Linear-Motor Type Flux Pumps With Converged Output Current Over 3.1 kA

Due to its low energy consumption and cost-effectiveness, contactless charging using flux pumps has emerged as one of the most promising candidates for replacing traditional superconducting DC power supplies. In our previous work, we have successfully developed a kilo-amp linear-motor type flux pump (W. Wang et al., Sep. 2022). In this study, we use two of such kilo-amp linear-motor type flux pumps to perform a convergence test to have reached a total current output of 3.1 kA, which is the highest output record of flux pumps up to this date. One of the two kilo-amp flux pumps was improved with its design, resulting in reduced power consumptions and a smaller volume, while maintaining the same output performance as the previous version (W. Wang et al., Sep. 2022). The parallel connection of the two flux pumps effectively extend the number of parallel superconducting stators, which expected to double the DC output current. The tests are performed in liquid nitrogen at 77 K, a remarkable 3,186 A DC output is recorded on the superconducting load. This paper also demonstrates the use of DC bias coil to modulate the amplitude and direction of pumping currents based on the "four-quadrant" current control method, which enable the flux pumps with bipolar output currents ranging from -3,145 A to +3,186 A. These experiments validate the method of combination modularized kilo-amp flux pumps to reach more than 10 kA output.