Cogging Torque Analysis of a Segmented Interior Permanent Magnet Machine

This paper investigates the reduced cogging torque seen in a prototype Segmented Interior Permanent Magnet (SIPM) machine. The Interior Permanent Magnet (IPM) machine in which the rotor pole magnets are segmented to provide an improved flux-weakening capability are called in this paper as the Segmented IPM (SIPM) machine. It has been seen that the cogging torque of the segmented IPM machine is much lower than that of a conventional, non-segmented IPM machine of similar ratings and dimensions. The cogging torques of both the segmented IPM machine and the conventional IPM machine were first calculated using finite element analysis and the results were later verified by the experimental measurements. The same stator was used for both the machine during calculation and measurements. The paper attempts to analyse the reasons behind the reduced cogging torque seen in the prototype SIPM machine.