Improved cogging calculation methods for surface mounted permanent magnet synchronous motors

As part of the design process of surface mounted permanent magnet synchronous
motors (PMSM), a combination of analytical calculation and finite element analysis (FEA) is
proposed for the cogging torque calculation. The analytical methods are recommended for the
initial design iterations in view of their high computational speed. In general, however, finite
element analysis is more accurate and is therefore recommended for the final design iterations. In
order to obtain continuity when switching from analytical calculations to FEA, two modifications
are made to the equations upon which the analytical methods are based in order to improve
accuracy. This is demonstrated by comparing the results from the unmodified and modified
analytical method with those using the finite element method through their application using the
nominal parameters of a Control Techniques Dynamics CTD 142UMC300 motor. Air-gap flux
density calculations are compared as well as cogging torque calculations.

Citation:
Sooriyakumar, G., Perryman, R., Dodds, S. J. (2007) ‘Improved cogging calculation methods for surface mounted permanent magnet synchronous motors’ Proceedings of Advances in Computing and Technology, (AC&T) The School of Computing and Technology 2nd Annual Conference, University of East London, pp.222-227.