Design and test of HTS rotor magnets for high energy density motor

Abstract High-temperature superconducting (HTS) technology enables the realization of compact and efficient designs, with the potential to break through the bottleneck of high-power-density motors. In HTS motors, field windings are crucial components that significantly influence overall performance. The motor’s power capacity is generally proportional to the air gap magnetic field ( B g ), which is further limited by the critical current of the HTS coils. In this paper, we designed and tested a single pole magnet for the HTS rotor that generated B g of 3.39 T for an air gap of 3.5 mm and 3.04 T for an air gap of 15 mm at 30 K. These results are promising for high-energy-density motors, especially for HTS motors intended for aircraft. In addition, we established a 2D axisymmetric numerical model accommodating the J c ( B , <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>θ</mml:mi> </mml:mrow> </mml:math> ) dependence of the critical current of HTS tapes to yield a more accurate estimation of the critical current of the racetrack coils. This methodology has been validated with various HTS tapes possessing different intrinsic flux pinning properties, demonstrating high accuracy and effective capability in simulating HTS coil performance. This work provided valuable guidance for the design and optimization of future high-power-density superconducting motors, while also validating a universal numerical simulation method.