Experimental and Numerical Study of a Trapped-Field Superconducting Machine With Axially Oriented HTS Tape Stacks

Second-generation (2G) high-temperature supercon ducting (HTS) tapes enable the development of compact, high power electrical machines due to their exceptional current carrying capacity. Trapped-field superconducting machines, in which stacks of 2G HTS tapes are used to replace bulk HTS material in the rotor, can achieve comparable flux-trapping performance while reducing the overall size and weight of the device. In previous works, we proposed a spiral stacking configuration to enhance their trapped field. In the present study, we extend this concept by investigating a rotor design where 2G HTS tapes are stacked with their wide faces oriented parallel to the machine axis. The machine was experimentally tested in a liquid nitrogen bath at 77 K, in which initial high-current DC pulses were applied to the stator to magnetize the rotor stacks. Subsequently, the shaft was driven at a constant speed, and the induced voltage was recorded. In parallel, finite element simula tions based on the J–A formulation implemented in COMSOL Multiphysics were conducted to analyze the stack magnetization and induced voltage. The simulated and experimental results were then compared. Finally, the SEM was tested in motor mode, and the torque was measured. These findings demonstrate the potential of axially stacked HTS tapes to enhance the design of next-generation trapped-field superconducting machines aimed at achieving high power density applications.