An approach for vibration quantification in SRM for design studies

It is well accepted that the primary source of acoustic noise in SRM is the stator deformations caused due to radially acting electromagnetic forces. Much effort has been reported in literature towards experimental determination of forces and Finite Element (FE) based models for the motor for study of electromagnetic and mechanical aspects. Several research works also propose approaches towards minimizing torque ripple and radial forces. An index to quantify the deformation that occur in an SRM that will enable comparison of various approaches to reduce vibrations is very much desirable. Towards this end, this paper proposes RMS displacement as a figure of merit, arrived at from a combination of circuit simulation and finite element studies. The approach used is computationally less intensive and is useful for estimating the performance of methods like Torque Sharing Function (TSF) usage. In this paper, a cosine TSF is used to demonstrate the suitability of the proposed index using this approach.