Design and modeling of a slotless and homopolar axial-field synchronous machine for a flywheel accumulator

A new axial-field synchronous machine designed for a flywheel accumulator is presented herein. The armature and field windings, fixed in the air gap, are made with double-face printed circuits. A specific armature layout provides a sine-distributed magnetomotive force and solves the problem of crossing the ends of the winding. A two-dimensional semi-analytical model at the mean radius, using surfacic permeances, is then developed. Then, inductances, torque, and eddy-current losses are calculated using this model and compared with experimental results.