The application of slotless skewed windings to a rim driven fan for aircraft electrical propulsion (AEP)

This paper investigates the slotless winding characteristics of motors intended for aircraft electrical propulsion (AEP), together with a preliminary design study of a winding model derived from a Faulhaber configuration. Geometrical relationships and magnetic requirements driving the design, such as the width of each phase coil side, the skew angle, and the winding arrangement, are analysed. Finally, electromagnetic (EM) simulations were conducted to study the electromagnetic performance of the Faulhaber model and the influence of the stator conductor skewness. Upon analysis of the results, it is found that the skew angle should remain low to assure efficiency, while it should also be great enough to satisfy the geometric and magnetic requirements. In conclusion, the paper proposes a hybrid slotless winding configuration based on the Faulhaber structure, which is a trade-off between efficiency and end-winding length for a motor powering a rim driven fan