Analysis of Vibroacoustic Behaviors and Torque Ripple of SRMs with Different Phases and Poles 2020-01-0467

In this study, the vibroacoustic characteristics and torque fluctuation 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. 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 finite-element results of radial force. Second, a multiphysics model, which was composed of an electromagnetic field, a mechanical field, and an acoustic field, was established to predict the noise behaviors of SRMs with different phases and poles. Third, the relationship between the torque fluctuation and the phases / poles 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 in all radial SRMs are kN_s/(2Q) and the frequencies are (QN₀±k/2)N_rf, where k=0,2,4···, N₀=0,1,2···, Q is the phases of SRMs, N_s is the stator poles, N_r is the rotor poles, f is the rotational frequency. Besides, the torque fluctuation gradually decreases as the phases and poles of SRMs increase, so a high-phase and high-pole SRM should be selected to acquire small torque fluctuation. 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 N_s/Q and the frequencies of (QN₀±1)N_rf. In addition, it can be found that the sensitivity of noise to the spatial order of radial force is higher than that to the frequency, and the sensitivity of noise to the frequency is higher than that to the magnitude.