Optimization of Cogging Torque in Surface Mounted PM Machines using PM Segmetation

Document Type : Original Article

Abstract

In this paper, the segmentation method is used to reduce cogging torque in the surface-mounted permanent
magnet machines. In this method the magnet pole is divided into several magnet blocks. The permanent magnet
is segmented in two ways, equal- and  unequal- size permanent magnet blocks. In the both methods the half-wave
symmetry of the magnetic poles is applied. The dimension of the permanen t magnet s is optimiz ed to reduce the
machine cogging torque using an analytical model combined with the genetic al gorithm. The effect  of the slotted
armature is taken into account in the analytical model. The  cogging torque is obtained from the air gap
magnetic flux components and the Maxwell’s stress tensor. The mo del is obtained by solving the Poisson’s
equation. This model is used as a fast tool to compu te the objective function in the ge netic algorithm. In addition,
the validity of the proposed model is verified with  finite element  analysis.  
 

Keywords


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