Investigation on synchronous reluctance machines with different rotor topologies and winding configurations

This study investigates the influence of rotor topologies and winding configurations on the electromagnetic performance of three-phase synchronous reluctance machines (SynRM) with different slot/pole number combinations, e.g. 12-slot/4-pole and 12-slot/8-pole. Transversally laminated synchronous reluctance rotors with both round flux barrier and angled flux barrier have been considered, as well as the doubly salient (DS) rotor as that used in switched reluctance machines. Both concentrated and distributed winding configurations are accounted for, i.e. single-layer and double-layer conventional and mutually coupled windings, as well as fully pitched winding. The machine performance in terms of d- and q-axis inductances, on-load torque, copper loss, and iron loss have been investigated using 2D finite-element analysis. With appropriate rotor topology, 12-slot/4-pole and 12-slot/8-pole machines with fully pitched and double-layer mutually coupled windings can achieve similar torque capacity, which are higher than the machines with other winding configurations. In addition, the synchronous reluctance machine with round flux barrier can have lower iron loss than DS reluctance machine under different working conditions. The prototypes of 12-slot/8-pole single layer and double layer, DS SynRM have been built to validate the predictions in terms of inductances and torques.