Comparison of single and three-phase permanent magnet motor drives

This article presents a comparison between two PM synchronous electrical motors of 0?5kW, a single phase machine and a three-phase machine designed for automotive applications. The single-phase structure developed by our laboratory displays the particularity of being completely symmetric: no mechanical or electromagnetic asymmetry. This machine starts with the maximum electromagnetic instantaneous torque and thus the corresponding current at the moment of start-up is very low. Both single and three-phase motor drives are designed with the same specifications. The calculation and optimization of electromagnetic parts are obtained thanks to the use of a corrected 2D finite element code in order to take into account the strongly three-dimensionnal aspect of these machines. The experimental results and projection made using a 3D finite element code will serve to validate our method, which includes saturation problems. A simulation of electrical equations is also developed and validated for each kind of motor inverter structure presented.