Development of transverse-laminated synchronous reluctance motor with sinusoidal anisotropic rotor for less torque ripple contents

D.Phil. (Electrical Engineering)Abstract: This thesis presents a novel Synchronous Reluctance Motor (SynRM), which has a sinusoidal rotor lamination shape in the axial direction. The sinusoidal lamination shape is utilized to vary the magnetic flux in the q-axis direction, therefore cancelling some torque harmonics produced by stator and rotor slotting effects. A method for evaluating, both qualitatively and quantitatively, the effects of specific rotor design parameters on the performance of the synchronous reluctance machine is presented. The method uses single-and multi-factor experimental designs, with Analysis of Variance (ANOVA), and Finite Element Analysis (FEA) to determine the optimal rotor design parameter for the novel SynRM, according to a specific objective. In addition to the unique criteria applied to the novel SynRM design process, a theoretical analysis is conducted to evaluate the effect of the number of stator slots and rotor slots (number of rotor segments), stator slot and rotor cut-off openings on airgap conductance harmonics. The analytical expressions for the novel SynRM take into account the Carter’s Factors due to the slot opening on both sides of the stator and the rotor, as the torque ripple is mainly caused by the variation of the d-and q-axis inductances, the oscillation of the Carter’s factor and the oscillation of the circulating flux component along the q-axis. Due to the axial geometry design of the sinusoidal lamination shape for the proposed machine, the 3-D Finite Element Method (FEM) is used for static and dynamic analysis. Taking into account the asymmetric nature of the axial geometry design of the sinusoidal lamination shape for the proposed SynRM, a comprehensive 3-D Finite Element Analysis (FEA) is performed. This is because with most electric machines with plane symmetry, the magnetic fluxes are calculated for unit depth and multiply by the stack length to find the actual magnetic flux in..