Investigation of the Effects of Dampers on the Dynamic Characteristics of an Axial-Flux HTS Machine With an NI HTS Field Coil

This paper presents research on the dynamic characteristics of electrical rotating machines using no-insulation (NI) high-temperature superconductor (HTS) field coils, particularly focusing on changes resulting from the application of dampers. Previous studies have indicated the potential for increased torque and armature current fluctuations in NI HTS machines compared to insulated HTS machines. NI winding enhances the electrical and thermal stability of HTS field coils, as overcurrent can be automatically bypassed through turn-to-turn contacts. However, the use of NI HTS field coils may compromise the operational stability of electric rotating machines under dynamic conditions. To address this issue, various studies are being conducted to increase the contact resistance between winding turns of the NI HTS coil. However, this could deteriorate the electrical and thermal stability of the HTS coil. Therefore, this study investigates the potential of improving the operational stability of electric rotating machines under dynamic conditions, like active short circuits, by applying dampers to the NI HTS machines.