Analysis of Vibroacoustic Behaviors and Torque Ripple of SRMs with Different Phases and Poles 2020-01-0467
In this paper, the vibroacoustic behaviors and torque ripple of switched reluctance motors (SRMs) with different phases and poles have been analyzed in detail. Also, the common four SRMs, i.e., three-phase 6/4 SRM, four-phase 8/6 SRM, five-phase 10/8 SRM, and six-phase 12/10 SRM, have been selected, which represent all the radial SRMs. First, the spatial-temporal distribution characteristics of radial force in SRMs were revealed by virtue of the analytical derivation, which was validated by the 2D Fourier decomposition based on the FEM results of radial force. Second, a multiphysics model, which was composed of an electromagnetic field, mechanical field, and acoustic field, was established to predict the noise behaviors of SRMs with different phases and poles. Third, the relationship between the torque ripple and the phases of SRMs, and the relationship between the noise and the radial force / phases / poles are all analyzed. Finally, the results show that the spatial orders of the radial forces, which are in all radial SRMs with any possible phase and pole, are kNs/(2Q) and the frequencies are (QN0±k/2)Nrf, where k=0,2,4···, N0=0,1,2···, Q is the phases of SRMs, Ns is the stator poles, Nr is the rotor poles, f is the rotational frequency. Besides, the torque ripple gradually decreases as the phases of SRMs increase, so a high-phase SRM should be selected to acquire relatively small torque ripple. Moreover, the noise peaks in the radial SRMs with any possible phase and pole combinations are mainly caused by the force harmonics with the spatial orders of Ns/Q and the frequencies of (QN0±1)Nrf. In addition, it can be found that the sensitivities of noise to the spatial order of radial force is higher than that to the frequency, and the sensitivities of noise to the frequency is higher than that to the magnitude.