# Research on Influence of Switching Angle on the Vibration of Switched Reluctance Motor
## 5 Conclusions  
This manuscript focuses on the influence of the change of turn-on angle and turn-off angle on the vibration of an SRM under the SAC strategy. The phase current of the SRM is presented in the form of a harmonic model, which is the Fourier series summation of several harmonic components. The current waveforms at various turn-on angles and turn-off angles are analyzed by Fourier transform. The analysis result shows that when the turn-off angle is constant, the current harmonic first decreases and then increases with the increase of the turn-on angle. In addition, when the turn-on angle is constant, the current harmonic shows the tendency of periodic oscillation with the variation of the turn-off angle, and the oscillation period is related to the harmonic order. To a certain speed for an SRM, the current harmonic order that plays a leading role in the second-order vibration can be deduced. By analyzing the value of this harmonic order, the variation law of vibration with the switching angle can be obtained. The effectiveness of the proposed method was verified on a 12/8 poles, 1.5 KW SRM drive system test bench. The result shows that when the SRM is rotating at the speed of 763 rpm, the variation law of vibration with the turn-on angle and turn-off angle can be reflected by its 12 th order harmonic component. It is seen that current harmonic components and vibrations change periodically with the change of the turn-on angle. When the turn-on angle is 21\({}^{\circ}\) and 24\({}^{\circ}\), the 12 th order current harmonic components and vibration amplitudes obtain the minimum value, respectively. Additionally, with the change of the turn-off angle, the harmonic components and vibrations of the 12 th order current show an approximate periodic oscillation tendency, with the oscillation period of 30\({}^{\circ}\). When the turn-off angle is around 138\({}^{\circ}\), the 12 th-order current harmonic and vibration obtain the minimum value. The combination of switching angles that minimizes the certain current harmonic component also minimizes vibration, which provides a new perspective on vibration suppression of SRMs.  
Figure 11: The 2 nd vibration under different turn-on (15–45\({}^{\circ}\)) and turn-off (125–145\({}^{\circ}\)) angles.  
**Author Contributions:** Conceptualization, X.L. and C.Z.; methodology, X.L.; software, X.L.; validation, X.L., C.Z. and L.Y.; formal analysis, X.L.; investigation, X.L.; resources, X.L.; data curation, X.L.; writing--original draft preparation, X.L.; writing--review and editing, X.L.; visualization, X.L.; supervision, J.Z.; project administration, J.Z.; funding acquisition, J.Z. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by National Natural Science Foundation of China (grant number 51935007 and 52175512) and the Science and Technology Committee of Shanghai (grant number 19142203600).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The study did not report any data.  
**Conflicts of Interest:** The authors declare no conflict of interest.