Harmonic contents in induced EMF and Electromagnetic Torque in mass produced sinusoidal PM brushless machines

This research provides a detailed finding of the harmonic contents in the induced voltage and developed torque in permanent magnet synchronous motors due to electromagnetic origins. Two fractional slot PM topologies are investigated to analyze the harmonic contents that is influenced by motor slot/pole and winding configurations. The research also points out the various sources responsible for producing harmonics through mathematical models as they appear in induced voltage and developed torque. The theory is presented by analytical formulas and finite element based modeling. Both analytical and FE based modeling are verified by building some motors of both topologies. Various practical build issues originated from both rotor and stator such as magnet placement and property variations and winding arrangements are considered. The research shows the sensitivities of different motor topologies under manufacturing tolerances for mass production.