Vibration and torque ripple reduction of switched reluctance motors through current profile optimization

Abstract

This paper proposes a differential evolution (DE) optimization-based current profiling method for simultaneous reduction of the torque ripple and vibration of switched reluctance motors (SRMs). The mechanism of torque generation in SRMs produces radial forces in addition to the required tangential force. It has been shown that the radial forces acting on the stator are the main vibration source in SRMs and keeping the sum of the radial forces constant can reduce the magnitude of the significant harmonics of the sum of radial forces and further reduce vibration by avoiding the resonance caused by those harmonics. A simple method is proposed to model the torque and radial forces generated in the SRMs while considering the saturation effects. The resulting torque and radial force models are then used in the DE optimization process to generate the current profile of each phase in the form of Fourier series, where the Fourier coefficients of each phase current profile are determined to minimize the torque ripple and significant harmonics in the sum of the radial forces. The proposed method significantly reduces the computational cost of the finite element analysis (FEA)-based methods. The effectiveness of the proposed method is verified through both FEA simulation and experimental results.