Design Solutions for Reducing the Cogging Torque of PMSM

This paper analyzes design solutions able to reduce the Cogging Torque (CT) amplitude of Permanent Magnet Synchronous Machines (PMSMs). The common point of these solutions is the particular constructions of the stator magnetic core from two concentric steel lamination stacks that leads to a closed stator slots structure in the air-gap region. The efficiency of the studied solutions is evaluated by Finite Element (FE) analysis for two different types of PMSMs: the first one with Surface Permanent Magnets (SPMs) and the second one with Interior Permanent Magnets (IPMs). The influence of the special stator constructions on the performances of the two types of machines is emphasized also in the paper, with positive and negative effects. This study proves that a PMSM whose stator magnetic core is designed as shown, leads to an important decrease of CT amplitude in comparison with a classical machine. Moreover, the studied design solutions may be mixed with other CT reduction methods so as to optimize the overall PMSM performance. A part of the numerical model results were experimentally validated.