Cogging torque reduction methods for internal permanent magnet motors: Review and comparison

Internal permanent magnet synchronous machines are spreading in industrial production. High torque density and extended speed operation range are key issues in many fields of applications. Many methods and design guidelines for cogging torque reduction exist in literature and this paper compares them. To this aim, the different design guidelines are applied to a reference machine to assess their effectiveness. Computer FEA analysis are carried out for each case in order to compare the cogging torque reduction potential of the different techniques. Other side effects, such as b.e.m.f and torque quality will be taken into account. The paper contribution is to compare various techniques on a common ground (the reference machine) to identify the most effective ones.