An Analytical Approach to Estimate the Cogging Torque in Segmented stator Synchronous Permanent Magnet Machines with large angular gaps

Abstract

This paper presents a new analytical model to determine the cogging torque of stator-segmented permanent magnet machines (with angular air gaps, i.e. flux barriers, located in the stator). Basically, if the saturation is not considered, the cogging torque can be seen as the sum of two independent contributions: the first contribution results from the cogging torque related to an equivalent slotless machine with a single gap, the second resulting from an equivalent non-segmented slotted machine. For the specifications of a marine current turbine generator, this analytical approach is evaluated and compared with a numerical 2D Finite Element Analysis (Flux™ 2D by Altair).