Experimental and Numerical Study on the AC Loss of HTS REBCO Winding for Fully Superconducting Electrical Machine

In superconducting electrical machines, the HTS windings are used to replace traditional copper armature windings to improve the power density. However, the HTS armature windings produce AC loss when carrying AC currents under AC magnetic fields in superconducting electrical machines. It affects the efficiency of the superconducting electrical machines. In this paper, a full-scale HTS REBCO armature winding is wound based on our 10kW superconducting synchronous electrical machine design, and the corresponding finite element model is also built based on <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</i>-<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">A</i> formulation. Under different amplitudes and frequencies of the AC currents, the AC transport loss of the HTS REBCO winding is analyzed by simulation and experiment. The results show that the simulation and the experiment have good consistency. Meanwhile, the AC magnetization loss of the HTS REBCO winding is analyzed by simulation under different amplitudes of the AC magnetic fields. We find that the magnetization loss is much higher than the AC transport loss of the HTS REBCO windings. Finally, under different amplitudes of the AC currents and AC magnetic fields, the total AC loss of the HTS REBCO winding is also analyzed. This work is the first step towards R&D of high power density superconducting electrical machines for future electric aircraft.