# Research on Influence of Switching Angle on the Vibration of Switched Reluctance Motor
## 1 Introduction  
A switched reluctance motor (SRM) is known for its simple construction, robustness, inherent fault tolerant structure and low production costs [1, 2, 3]. However, due to the double salient pole structure and switching operation mode of the SRM, it will generate a pulsating radial force during operation, and the radial force acts on the electronic stator to cause vibration and acoustic noise, which limits its application in the industrial potential market [4, 5]. The existing research to suppress vibration for an SRM is mainly divided into two categories; the first category is to change the motor topology structure from the aspect of motor design, whereas the second one is to realize the vibration suppression of the SRM by the control strategy. In terms of optimal design of the motor structure, vibration suppression is mainly achieved by changing the structure of the motor body. For instance, [PERSON] et al. [6] and [PERSON] et al. [7] proposed one-phase and three-phase salient-pole SRMs, respectively. [PERSON] and [PERSON] [8] proposed a dual-stator SRM, which proved that the double stator structure can effectively reduce the vibration. [PERSON] et al. [9] proposed an optimized segmental rotor SRM with a greater number of rotor segments than stator slots. [PERSON] et al. [10] realized vibration reduction of the SRM with a high number of poles. There is lots of research on vibration suppression from the aspect of control strategy, such as,switching angle adjustment [11], inserting of zero voltage loop during switching [12] and current waveform profiling [13; 14]. Among them, switching angle adjustment is widely used due to its simple implementation. In the control strategy of the switched reluctance motor, the turn-on angle and the turn-off angle are two important control parameters that have a direct impact on the performance parameters of the switched reluctance motor, such as torque, torque ripple, efficiency, vibration and noise [15; 16]. The way of controlling the operation of the switched reluctance motor by adjusting the turn-on angle and turn-off angle is called switching angle control (SAC), and this method is widely used because of its simplicity [17; 18]. The main control parameters of the SAC control strategy include turn-on angle, turn-off angle and duty cycle. Studies have shown that limiting the current change rate by adjusting the switching angle can effectively reduce the vibration and noise of the switched reluctance motor [19; 20]. At present, scholars at home and abroad have carried out research on the optimization of switching angle. For example, [PERSON] et al. [21] achieved the vibration reduction goal by randomly adjusting the turn-off angle. [PERSON] et al. [22] compared the switching angle random adjustment method with other vibration reduction methods and verified the effectiveness of the random adjustment of the switching angle method. [PERSON] et al. [23] considered the influence of back EMF and proposed an analytical model of the turn-on angle and turn-off angle and optimized the turn-on angle based on the model. However, there is still a lack of research on the influence of the switching angle on the vibration of the switched reluctance motor, and the switching angle optimization algorithm has shortcomings, such as low efficiency. This manuscript focuses on the influence of the change of turn-on angle and turn-off angle on the vibration of a switched reluctance motor under the angle control strategy. The influence of on angle and off angle on a current harmonic component is analyzed in detail, and the vibration caused by the consistency of current harmonic component frequency and motor natural frequency is studied. Then, the effectiveness of the proposed method was verified on a 12/8 poles and 1.5 KW SRM drive system test bench. In Section 2, the principle of the switching angle control method is presented. Section 3 shows the influence of the switching angle on vibration of an SRM.