Vibration Analysis of a Double-Stator Switched Reluctance Machine

Vibration and acoustic noise form two major restrictions for widespread use of switched reluctance motors (SRM) in many applications. Low-frequency vibrational modes can be excited by electromagnetic force harmonics and produces low-frequency acoustic-noise causing a great discomfort. Double stator switched reluctance machine has substantially lower acoustic noise and vibration when compared to conventional SRM drives. This paper investigates the origin of low frequency vibrations in a double-stator switched reluctance machine (DSSRM). The proposed method can be extended to other electric machine topologies as well. Modal and structural analyses are performed using three-dimensional finite-element method to identify parts associated with these low-frequency vibrations. Different experimental approaches also presented to verify numerical analyses. It is shown that low-frequency natural modes of inner parts can effectively contribute to vibration and acoustic noise by the virtue of transmission to the housing through bearings.