Research On Torque Ripple Reduction Of Switched Reluctance Motor

Switched reluctance motor is widely concerned for its simple structure,low cost,high reliability and wide speed range,which have developed rapidly in recent years.However,due to its own double salient pole structure and the high nonlinearity of winding current,the torque ripple is big and the noise is big,which limits its application in many fields.Reducing its torque ripple and broadening its application fields has become one of the hot spots in the field of switched reluctance motor.To solve this problem,we discuss the control schemes of direct torque control in 12 sectors,vector optimization in commutation zone and flux deadbeat direct torque control emphatically based on the research of SR motor direct torque control strategy.Firstly,based on the literature review of SR motor at home and abroad,the development background and research status of SR motor are expounded,and the cause of torque ripple is analyzed.The magnetic flux linkage and torque characteristics of the SR motor are obtained by Ansoft two-dimensional finite element simulation,and the model of the motor is established.The direct torque control algorithm of SR motor is simulated by MATLAB/Simulink.Secondly,based on the analysis of torque ripple of basic voltage vector direct torque control,a direct torque control scheme of SR motor under 12 sectors is proposed.The system simulation diagram is also set up in MATLAB/Simulink,and compared with the traditional 6-sector direct torque control,the feasibility of the algorithm is verified.Simulation results also show that the torque ripple becomes larger in the commutation zone,and the reason of the phenomenon is explained theoretically.The method of vector optimization in commutation area is put forward,and the system simulation diagram is set up in MATLAB/Simulink environment.And the effect of the space voltage vector on the torque suppression is verified.Thirdly,we found that the direct torque control is a tolerance control due to the hysteresis of the bang-bang control,to overcome the disadvantages of the large torque ripple in traditional direct torque control of switched reluctance motors,flux deadbeat direct torque control method is presented.We obtain the error of the feedback torque and flux with the given value and derive a space voltage vector to compensate for the torque and the flux.The space voltage vector is composed of the adjacent basic voltage vectors.Then,based on the theory of flux deadbeat theory,a simulation diagram is built in the MATLAB/Simulink environment according to the system block diagram,and compared with the traditional direct torque control.Through the simulation,it can be clearly seen that the flux deadbeat method has better restraining effect on torque ripple.Finally,the direct torque control in 12 sectors and the vector optimization in commutation zone are experimentally analyzed on the hardware experiment platform,the experimental results show that these two methods are effective for reducing the torque ripple.