Study on AC Loss Reduction in HTS Motors for Electrified Aircraft Propulsion

High temperature superconducting (HTS) motor technology is one of the most feasible solutions to achieve the power-to-weight ratio (PTW) needed in electrified aircraft propulsion (EAP). The AC losses generated by HTS coils for armature winding affect the performance and safety of HTS motors. In this paper, for the ac loss reduction, we study a method to reduce the perpendicular magnetic field applied to the surface of the coil by placing permeability flux diverters (FDs) around the coil. To investigate the effect of the size and position of the FDs on ac loss reduction, we establish a 2D numerical calculation model with alternating external magnetic field and alternating current. Numerical calculation results show that the FDs can significantly reduce the magnetic field on the surface of the coil. Through the normalization process, we find that the optimal size of the FDs has a similar correspondence for coils of different sizes.