Influence of stator slot and pole number combination on rotor bar current waveform and performance of induction machines

This paper investigates the influence of stator slot/pole number combinations on the rotor bar current waveform and electromagnetic performance of a squirrel-cage induction machines (IMs) designed with a slot number per pole per phase of two. 36-slot/6-pole (36S6P), 48S8P, and 60S10P IMs, all having 52 rotor slots, have been designed by using the same winding layout, stator outer diameter, stack length, stator current, and rated speed as the Toyota Prius 2010 interior permanent magnet machine (IPM). The waveforms of flux density in different parts of stator and rotor, and the leakage flux in the slots are considered and their influences are investigated. It has been revealed that even if the winding layout is the same, the stator slot/pole number combination has a considerable effect on the distortion level of the bar current and the electromagnetic performance, including torque, torque ripple, power factor, and efficiency.