| Switched reluctance motor(SRM)is widely used in many fields because of its simple structure,low cost and high mechanical strength.However,because of its special structure,it is necessary to use position sensors to obtain rotor position information to control it,which not only increases the cost of the control system,but also limits the application of the motor in extreme environments.In particular,the current combination of position sensorless and vibration and noise suppression control strategies is poor,and the research is still incomplete.Therefore,the joint research on the two control strategies of SRM is of great significance.Therefore,in the high-speed control of the motor,aiming at the above two problems,this paper proposes a SRM control strategy that combines an improved phase current gradient method with vibration suppression control.Firstly,when the SRM is controlled by PWM chopper voltage regulation,the winding current is sawtooth,and the processor of control system can only process discrete digital quantity,which leads to that the current peak cannot be accurately obtained according to the sampled current,so that the detection accuracy of the current-gradient method is reduced.In this paper,a method of using interpolation method to fit the sampling current is proposed to make the discrete sampling current continuous,so as to improve the detection accuracy of the current peak in the phase current-gradient method.Secondly,the position of the peak current will fluctuate due to the influence of the operating parameters of the motor,resulting in the uncertainty of the position update angle and the decrease of the position detection accuracy.In this paper,an improved phase current-gradient method is proposed.This method establishes a mathematical equation based on the relationship between the current,inductance and rotor position in the motor.The method reduces the influence variables of lookup table method,reduces the amount of experiment and the calculation of processor,and improves the accuracy of position detection.Then,in order to solve the problem of poor combination effect between the sensorless control method and the vibration suppression control.This paper first analyzes the influence of phase current-gradient method on the vibration generated by SRM.Secondly,this paper proposes the joint control of the phase current-gradient method and the variable turn-off angle control to reduce the motor vibration without affecting the detection accuracy of the sensorless control.Finally,the simulation model is built by MATLAB/Simulink,and the simulation results of the proposed control strategy are analyzed.Taking a three-phase 12/8-pole SRM as the experimental prototype,the hardware experimental platform was built and the control algorithm software program was designed.The simulation and experimental results show that the proposed method in this paper can effectively improve the detection accuracy of the traditional current-gradient method and suppress the vibration and noise of the motor. |
