New Approach to Cogging Torque Simulation Using Numerical Functions

This paper presents a new approach for simulation of the cogging torque in a permanent-magnet (PM) machine. The method exploits the numerical functions for modeling the magnetic circuit of the machine. This paper introduces two improved functions to model the PMs and the air-gap permeance, aiming to compute the cogging torque in the PM machine. The first function states the magnetomotive-force drop on the machine air gap with respect to the angular position. The other function, named permeance function, models the air-gap permeance accurately, taking into account the stator saliency due to the teeth. The described procedure has been tested on a prototype PM machine.