REBCO Trapezoidal Armature Windings for Superconducting Induction Motors

For extensive use in electric vehicles, electric airplanes, and other such applications, superconducting motors are designed to be lightweight and have a high power density. Rare-earth barium copper oxide (REBCO) tapes are considered a potential material for use in these motors because of their high critical current density. Because REBCO can be modeled into tape shapes, motors with racetrack coils as armature windings have been studied. However, racetrack coils are inferior in terms of increasing the interlinkage flux to the rotor compared with distributed windings. In this study, we propose trapezoidal REBCO tape coils for shaping armature windings into distributed windings. Next, 2 kW-class induction motors using two types of coils—the trapezoidal and racetrack coils—were designed to compare the characteristics of the two motors. The JMAG-Designer software was used to perform electromagnetic simulations on the two models. The results revealed that the motor with trapezoidal coils required less REBCO tapes and exhibited a lower vertical component of magnetic flux density than the racetrack coils did. Therefore, the AC loss of the trapezoidal coils becomes lower than that of the racetrack coils, and the trapezoidal coils weigh less than racetrack coils.