Influence of additional magnetomotive force caused by transport current on linear flux pumps

Abstract Linear flux pumps are devices that apply a traveling magnetic field to a high-temperature superconducting (HTS) tape to generate voltage output for HTS magnets. In these systems, the traveling field is generated by an iron loop and excitation current. This work presents a quantitative comparison between experimental and simulated performance of a linear flux pump. The study reveals that the magnetomotive force (MMF) generated by the transport current in the HTS tape is not negligible and breaks the symmetry when both the field direction and sweeping direction are reversed. After incorporating the additional MMF in the simulation, the flux pump’s performance—including the average terminal voltage, Joule heating, output power, and efficiency—shows satisfactory agreement between experiment and simulation. The simulation used in this work is based on Brandt’s method, with significant modifications to incorporate time-dependent boundary conditions for both transport current and applied propagating field. The key to quantitative study of the flux pump is the experimental methodology, where local time-dependent electric fields <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>E</mml:mi> <mml:mi>y</mml:mi> </mml:msub> <mml:mo stretchy="false">(</mml:mo> <mml:mi>x</mml:mi> <mml:mo>,</mml:mo> <mml:mi>t</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> , instead of terminal voltage is measured, avoiding the difficulty of terminal voltage simulation and providing more details including the Joule heating due to flux motion. The fundamental vortex dynamics is used as the theoretical framework connecting simulations with experimental observations, offering physical interpretation of the measured phenomena.