Comparison of Flux-Trapped Superconducting Machine Configurations

Superconducting devices offer innovative solutions for the energy transition, with superconducting machines showing promise in applications such as aircraft propulsion and power generation. In this context, the present work compares three configurations of flux-trapped machines that utilize second-generation (2G) high-temperature superconducting (HTS) tapes in the rotor. The prototypes include only one machine with three rotor configurations; one wound with 2 turns of a single 50 mm-wide tape, one with 6 turns of three 12 mm-wide tapes and one with 18 turns of three 12 mm-wide tapes as well. The objective is to assess the performance of each configuration when operating the machine as motor and generator. For the generator tests, the machine was magnetized using high-intensity (up to 100 A) and short-duration (100 ms) direct current pulses supplied to the stator. Following the magnetization, a propulsion motor was coupled to the shaft of the machine, and the induced voltage at the generator's output was measured. Results indicated that the prototype with the 50 mm-wide tape has higher efficiency than the other topologies. However, this configuration did not fully realize its potential due to the limited number of turns, restricted to only two, here. This study provides valuable insights into the impact of 2G HTS rotor configurations on the performance of flux-trapped superconducting hybrid machines (superconducting rotor and conventional stator), both as motors and generators, with a focus on their future applications.