Fault-Tolerant Fractional-Slot PMSMs with One Coil Parallel Branches Made Phases. Part 2: Circulating Harmonic Current Rejection Potential

The paper is aimed at a class of fractionalslotpermanentmagnet synchronousmachines (FSPMSMs)equipped with phases made up of one coil parallelbranches, with emphasis on their potential to reject theharmonic currents circulating in the loops created by theparallel branches. Following the identification and topologicalcharacterization of this class of machines in Part 1,the star of slots approach is extended to the analysis ofthe back-EMF harmonic content. This makes it possible theinvestigation of the possible circulating harmonic currentsby checking the phase shifts between the different back-EMF harmonics induced in the coils belonging to eachphase. It is shown that all candidates identified in Part1 exhibit the potential to reject circulating harmonic currents.The paper is achieved by a case study dedicated toa candidate equipped with three phases made up of sixparallel branches including a single coil each. Its featuresare predicted by a 2D finite element analysis. Selected noandon-load features are experimentally-validated.