Vibration Suppression for Flux-Switching PM Machines

The flux switching permanent magnet (FSPM) machines are widely studied in recent years due to their robust rotor structure, good flux-weakening capability, good heat dissipation, etc. Nevertheless, they always suffer from serious vibration and noise as a result of the doubly-salient structure. In this paper, the analytical expression of the air-gap electromagnetic force in regular FSPM machines is derived in terms of spatial order and frequency, and it shows that the FSPM machines with a close stator-rotor tooth combination would produce serious stator vibration owing to the low-order spatial harmonics in the air-gap electromagnetic force. In this paper, a dual-stator dual-rotor (DSDR) FSPM machine topology is presented to suppress the stator vibration. First, the operating principle and the mechanism of vibration suppression of the DSDR machine topology are investigated in detail. Meanwhile, its influences on the electromagnetic performances, such as the output torque and end effect, are also investigated. Finally, two prototypes, the regular topology and the DSDR topology, are designed, manufactured, and tested. The experiment results verify the analysis, and it is found that the maximum and averaged vibration velocity amplitudes of the dominated harmonic can be reduced to 54% and 41%, respectively, by using the DSDR topology.