Analytical determination of optimal split ratio for interior permanent magnet synchronous motor

Abstract

This paper shows that the split ratio of the stator inner diameter to the outer diameter has an influence on the airgap flux density, stator copper loss, thermal load, torque density and cost for interior permanent magnet synchronous motors (IPMSMs) applied in electric vehicles (EVs). This paper presents a simplified analytical method to study the optimization of the split ratio considering both the efficiency and cost. The validity of this method is verified by experiment on a 35kW prototype.Index Terms-Electric vehicles (EVs), interior permanent magnet synchronous motors (IPMSMs), split ratio, stator copper loss, thermal load.