Active Reduction of Charging Time Constant in Iron Core NI-HTS Magnet for Superconducting Motor

Abstract

The iron core in superconducting motors significantly increases the time constant of no-insulation (NI) high-temperature superconducting (HTS) coils, which limits the dynamic response capability required for applications such as quench protection. This paper proposes an active method for reducing the time constant of NI HTS coils by utilizing the motor’s inherent magnetic circuit. Specifically, stator windings are introduced to form a coupled system with the NI coil, which dynamically reduces the equivalent inductance during the discharge process. A calculation model for the stator windings and NI coil coupling is established, combining mathematical analysis with finite element model (FEM) to verify the proposed approach. Simulation results demonstrate that the proposed method can effectively reduce the time constant of iron-core NI HTS coils under the considered operating conditions, confirming the feasibility of improving the dynamic performance of such coils in HTS motor.