Design of Doubly Salient Permanent Magnet Motors With Minimum Torque Ripple

This paper presents a design approach for doubly salient permanent magnet (DSPM) motors, aiming to minimize the torque ripple. The key is to propose the design criteria that the reluctance of all magnetic paths is the same, and the armature windings can be artfully connected to compensate the variation of self-inductance. Based on these criteria, the magnetic characteristics become symmetric, and the variation of self inductance is suppressed. Thus, the resulting torque ripple can be minimized. By using the time-stepping finite element method, the proposed DSPM motor and the existing DSPM motor are quantitatively compared in terms of their back-EMFs, self-inductances, and torque ripples, hence confirming the validity of the proposed design approach.