MMF harmonic analysis of polyphase windings based on the closed-form analytical equation

The several new winding configurations, such as fractional slot concentrated winding and concentrated winding with two slot pitches, have been attracted lots of attentions due to their inherent advantages such as short ending winding, easy manufacture and so on. However, these winding configurations are always suffer from much richer magneto motive force(MMF) harmonic contents and their MMF waveforms are far from sinusoidal waves compared to regular integer slot winding, and this leads to that the existing the MMF analysis equations built for regular integer and factional slot distribution windings do not work well for these novel winding configurations, especially for poly-phase windings, whose phase number is not three. This paper proposes general equations for predicting the harmonic order for any poly-phase windings. The phase belt, distribution and slot pitch factors for multiphase winding configuration with highest fundamental are derived. Based on the proposed equations, the key electromagnetic performances of multiphase winding including regular three phase winding, such as harmonic orders and contents, can be efficiently and effectively predicted and calculated. Finally, Several FEA models are built to verify these equations.