| Switched reluctance motor has the advantages of simple structure,high reliability,wide speed range,good fault tolerance,and no need for rare earth permanent magnet materials.It has broad application prospects in many fields such as aerospace,electric vehicles,mining machinery and household appliances.However,the special doubly salient structure and pulse power supply mode of switched reluctance motor lead to serious torque ripple and noise during its operation,which greatly limits its application.Aiming at the problem of torque ripple suppression of switched reluctance motor,a series of researches are carried out in this paper.The main contents are as follows:Firstly,starting from the structure,principle and basic mathematical model of switched reluctance motor,the linear mathematical model based on simplified phase inductance characteristics and the nonlinear mathematical model based on Fourier series are deduced and established.Based on the in-depth analysis of the switched reluctance motor drive system,the simulation model of the switched reluctance motor drive system is constructed,and the basic operation mode of the motor current chopping is simulated and analyzed,which provides the basis for the verification of the subsequent control algorithm.Secondly,aiming at the problem of significant torque ripple in switched reluctance motor,a high-performance indirect instantaneous torque control method based on adaptive PI algorithm is proposed.This method realizes the accurate mapping from phase torque command to phase current command through PI iterative learning control algorithm,and uses the learning ability of iterative learning algorithm to eliminate the solution error of traditional linear torque model.On this basis,an adaptive PI current loop is designed according to the characteristics of the incremental inductance of the switched reluctance motor,so as to realize the automatic adjustment of the gain of the current controller,and eliminate the influence of the inductance on the tracking performance of the current loop at different positions,thereby suppressing the torque ripple of the switched reluctance motor.Based on the three-phase 12/8 pole switched reluctance motor control system,the simulation analysis is carried out to verify the effectiveness of the proposed high performance indirect instantaneous torque control strategy.Thirdly,the switched reluctance motor drive system has the disadvantages of nonlinearity and complex time-varying parameters,which makes it a great challenge to establish its accurate mathematical model.At the same time,factors such as ambient temperature,magnetic saturation and loss can easily lead to changes in motor parameters.Aiming at the above problems,a robust indirect instantaneous torque control method for switched reluctance motor without relying on the accurate model of motor is proposed.Based on the principle of error feedback,this method directly compensates the solution deviation of the linear torque inverse model by using the phase torque error,and realizes the accurate mapping from torque to current.On this basis,the model-free predictive control is used to replace the traditional current chopping control.In order to overcome the nonlinearity of the motor,the ultra-local model is used as the equivalent model of the motor,and the linear extended state observer is used to estimate the internal disturbances such as parameter changes.Finally,the predicted current and disturbance generated by the linear extended state observer jointly output the reference voltage value,which is isolated and amplified by the pulse width modulation to the power converter to complete the torque smoothing control.The effectiveness of the torque control method in parameter robustness and torque ripple suppression is verified by simulation.Finally,a 1.5k W three-phase 12/8 pole switched reluctance motor experimental platform based on DSP28377 as the main control chip is built,and the drive control algorithm proposed in this paper is implemented by software.The experimental results verify the effectiveness of the proposed torque control strategy in current steady-state tracking and torque ripple suppression. |
