Research And Implementation Of Torque Ripple Reduction Strategy For Switched Reluctance Motor

Switched Reluctance Motor has attracted more and more attention due to its low cost,high reliability,high efficiency,and wide speed range.It has been applied to the traction,aerospace,electric vehicle and other industrial applications.However,the switched reluctance motor stator and rotor are unique doubly salient structure,and the phase current operation is pulsed type,these two aspects lead to problems of large torque ripple and high vibration noise,greatly limiting the further development of switched reluctance motor.In this paper,a torque ripple suppression strategy for SRM based on current rate prediction is proposed.The reference current is obtained by the torque distribution function(TSF)and the torque-current inverse model based on the quasi-linear flux linkage model.By increasing the current dynamic response capability,the actual current controlled by the proposed strategy can accurately track the reference current quickly,therefore the torque ripple is reduced.SRM torque ripple and noise are suppressed mainly by optimizing the motor body and the motor control strategy.This paper introduces the working principle,mathematical models and three basic control modes of switched reluctance motor,and analyzes the mechanism of torque ripple generation of switched reluctance motor.Various control strategies for suppressing torque ripple of switched reluctance motor are studied,whose advantages and disadvantages are summarized.The key to torque control of switched reluctance motor is controlling the motor current.This paper introduces asymmetric half-bridge power converter whose working modes has positive pressure mode,negative pressure mode and zero pressure mode,and then gives the rate of stator current change under these modes.Based on this,a torque ripple suppression strategy using current rate prediction is proposed.According to the current,rotor position,speed and incremental inductance,the proposed method predicts the required voltage duty cycle which enable the actual current to accurately track reference current.The control strategy improves the tracking accuracy of the current,so that the current accurately meets the requirements of the torque distribution function and reduces the motor torque ripple.In this paper,a back electromotive force estimation method based on quasi-linear flux linkage model is proposed to realize the current rate prediction algorithm,which increases the algorithm calculation speed.The reference current is directly calculated using quasi-linear flux linkage model without storing the nonlinear torque-current inverse model data.The MATLAB/Simulink simulation model of the proposed strategy is built and simulations in various working conditions are completed,the results show that the method improves the motor current tracking capability and reduces the motor torque ripple.The STM32-based switched reluctance motor control system is designed.The algorithm software program is also written.The experimental results verify that the proposed scheme can effectively suppress SRM torque ripple,and the system has better dynamic and steady-state performance.