Research On Low Torque Ripple Control System Of Switched Reluctance Motor

As a new type of speed regulating motor,Switched Reluctance Motor(SRM)has simple and sturdy structure,low cost,high operation efficiency,simple and flexible controllability and many other advantages,it has been widely used in various fields of life and industry,such as aerospace and electric vehicle drive system,etc.But the particularity of its structure and the nonlinearity of electromagnetic characteristics make its torque ripple is larger than other motors under operation,which limits the further application and promotion of SRM.Therefore,how to solve the large torque ripple effectively has become the research hotspot.This dissertation focuses on this problem,through the analysis of the principle and operating characteristics,puts forward SRM direct torque control strategy based on the space voltage vector in commutation region.Firstly,this dissertation introduces the current development of SRM and the research status of torque ripple reduction at home and abroad.Based on the analysis of the working principle and mathematical model of SRM,the Ansoft software is used to simulate two-dimension finite element of 12/8 poles prototype,this dissertation obtains the static characteristic curve of flux linkage,torque angle,etc.The Nonlinear simulation model of SRM prototype is established using curve data and the module of MATLAB/Simulink,through the simulation results,the correctness of the nonlinear simulation model is verified.Secondly,this dissertation analyzes the principle and advantages of direct torque control strategy and its implementation on SRM.Aiming at the torque out of control phenomenon,an improved SRM direct torque control method is proposed by analyzing the disadvantages of using basic voltage vector,the torque out of control phenomenon is improved by adding the voltage vector in commutation region.Then,the dynamic simulation model of direct torque control system is set up,the control system by using the basic voltage vectorand improved voltage vector is simulated,at the same time,compared with the current chopping control strategy simulation.Based on the analysis of simulation results,the improved direct torque control strategy is verified to improve the torque out of control phenomenon and reduce the torque ripple partly,meanwhile,the stability of the control system is improved.Finally,TMS320F28335 is used as the control core,the experimental platform of SRM driven control system is set up,this dissertation expounds the drive circuit of power converter,signal detection and modulation circuit,auxiliary power supply circuit and some of the software process,the experiment of direct torque control is carried out,through comparing the experimental waveform and the simulation waveform,the improved direct torque control is proved to have good effect on improving the torque out of control and reducing the torque ripple of SRM.