Comparison of the Eccentricity Faults Effects on the Performance of several Toroidal Wounded Axial Flux Permanent Magnet Motors

Eccentricity fault is one the most common fault types of disk-type permanent magnet machines, which could lead to devastating effects. Unfortunately, most of the previous works have studied this fault and its detection techniques for slotted structure with common winding. Therefore, in this paper, the effects of eccentricity faults on the performance of single-sided slotted, single-sided slotless, double-sided slotted, and double-sided slotless structures, all of which are toroidal wounded, are studied. For this purpose, for each of these structures, full load and absolute no-load conditions at three healthy, dynamic eccentricity, and static eccentricity states have been modeled by using 3D finite element transient analysis. Various performance characteristics, i.e. total input current, current in parallel paths, coils circulating current, total flux linkage, flux linkage of each coil, torque, and axial force on rotor, have been extracted.  The eccentricity faults effects on the performance of these motors have been studied through the analysis and comparison of these characteristics. According to the obtained results, using slotless stator and double-sided structure would lead to great reduction of the undesired effects of these faults. Moreover, it will be shown that conventional detection techniques of eccentricity faults may not be effective for some structures.