Axial-field synchronous machine with homopolar flux in the airgap 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 airgap are made with double-face printed circuits. A specific armature layout provides a sine-distributed MMF and solves the problem of crossing the ends of the winding. A 2D semi-analytical model at the mean radius, using surface permeances, is then developed. Afterwards, inductances, torque and eddy current losses are calculated using this model and compared with experimental results.