Torque Ripple Reduction Strategy for Doubly Salient Electromagnetic Machine Based on Current Given Function

Abstract

Torque ripples caused by the particular doubly salient structure of the doubly salient electromagnetic machine (DSEM) restrict its application in the field requiring high performance. This article employs the current given function (CGF) to propose a torque ripple reduction strategy for DSEM to enhance the torque capability. The optimal current profile for minimizing the copper loss is obtained based on the theoretical analysis. It is found that the obtained three-phase currents are distributed according to the phase torque coefficient that represents the torque capability of each phase. Then, to minimize the torque ripple and copper loss, four CGFs are proposed to distribute the reference current of each phase according to the torque characteristics of DSEM. Finally, the influence of overlap angle on the proposed strategy is analyzed to select the reasonable CGF and overlap angle under different operating conditions through simulation, improving the current tracking performance and torque–ampere ratio. The simulation and experimental results demonstrate the effectiveness of the proposed strategy in suppressing torque ripple and improving the torque–ampere ratio.