Analytical evaluation of Electromotive Forces in Doubly Slotted Synchronous Machines with Distributed Windings

An accurate, analytical evaluation of the e.m.f. waveforms in isotropic synchronous machines is developed, by employing a suited analytical field model. To this aim, the flux linkage of each armature coil is evaluated, as a function of time and rotor position, subsequently obtaining the phase flux linkage by suitably summing the coil contributions: the method, for now limited to unsaturated conditions, takes into account the actual winding features (field N° of slots/pole; armature N° of layers, N° of slots/(pole×phase), coil pitch), as like as the air-gap core geometry (air-gap and slot opening widths). Some comparisons with FEM simulations have been performed, obtaining very good agreement with the analytical results.