A comparative study on electromagnetic vibration of Doubly Salient Electromagnetic Machine with concentrated and distributed field windings

Noise and vibration problems originated from the salient poles of the stator and rotor are the major shortcomings for the application of the Doubly Salient Electromagnetic Machine (DSEM). In this paper, two DSEMs with distributed field windings and concentrated field windings are comparatively studied in terms of not only basic electromagnetic (EM) performances but also in terms of EM force, vibration modes and electromagnetic vibration characteristics. Both analytical and numerical result shows that the spatial distribution of the EM force is strongly dependent on the stator/rotor pole combinations. The modal analysis result suggests that resonant fequencies of the stator can be increased when housing and bolt connections are considered. Finally, the harmonic response shows that the 12s/8r DSEM with concentrated field windings has better performance in terms of the vibration than the 12s/10r DSEM with distributed field windings due to the thicker yoke and the higher spatial orders EM force harmonics.