Calculation of inductances and torque of an axially laminated synchronous reluctance motor

This study focuses on the calculation of inductances and torque of a synchronous reluctance machine having an axially laminated anisotropic rotor. Two techniques based on the winding function (WF) theory are used for the computations. One technique, of the conventional type, uses analytical expressions representing the airgap and the winding whereas the other uses the developed model of rotor and stator geometry shapes with winding placement positions. The second procedure does not make the assumption that the windings are sinusoidally distributed and includes all harmonics while avoiding the cumbersome integrations associated with the conventional WF procedure. The effects of stator slots and rotor axial lamination insulations introduce noticeable distortions in the inductances and torque plots. The results, transformed to rotor reference frame, yielded cross-coupling inductance components. Saturation is modelled by considering the airgap length as a variable, depending on the airgap flux. The results obtained with both WF procedures are compared with results of finite-element calculations and an acceptable correlation is observed.