Calculation on the Winding Factor and Armature Reaction MMF of a PMSM with 5-phase Fractional-slot Winding

In this paper, a permanent magnet synchronous machine with fractional-slot and 5-phase winding is studied. By superposing of the back EMF (electro-motive force) phasors of all coil-sides in a phase winding, the winding factor of the machine is calculated. The idea of this calculation method is a clear, and operation is easy and fast. In normal working, one-phase open-circuit fault, opencircuit fault of two adjacent phases, and open-circuit fault of two non adjacent phases states, the armature MMFs (electro-motive forces) are calculated, and the contents of their harmonics are analyzed, the forward and reverse rotating MMFs are discussed. The drawn results can be applied to analyze the running states of the machines, guide machine design and control.