Permanent Magnet Machines with Two Stators: A Comparative Analysis

Abstract

A comparative analysis of two different permanent magnet machines is presented in this study. The developed machines have double stator configuration and belongs to the class of flux-switching PM machines. Finite element analysis (FEA) technique is implemented in all the calculations. Type A machine produces higher air-gap flux-density and greater resultant coercive force (coercivity) than its Type B counterpart. Moreover, Type A machine has lower cogging torque and torque ripple compared to Type B, in addition to desirable smaller amount of iron and permanent magnet (PM) eddy current losses; though, with higher voltage distortion. Further, both machines have comparable output torques; all the same, with marginal torque amplitude credited to Type A machine. However, Type B machine exhibits superior efficiency at lower speed even beyond twice the rated operating speed, when simulated at constant copper loss condition. The investigated machines could be used either in motoring or generating mode, depending on the winding arrangement.

Keywords: Air-gap flux-density, efficiency, electromagnetic torque, losses, and two stators