Deadbeat Direct Torque Control Of Permanent Magnet Synchronous Motor Based On SVPWM

In recent years,the high-efficiency and energy-saving permanent magnet synchronous motor(PMSM)and its control strategy have become the development trend.It has important theoretical research and application value to improve the control performance of permanent magnet synchronous motor.As a high-performance motor control method,direct torque control(DTC)has become a hot research topic and has obtained many research results.Aiming at the disadvantages of direct torque control system of surface mounted permanent magnet synchronous motor(SPMSM),such as large torque and flux ripple and poor performance at low speed,a deadbeat direct torque control strategy of permanent magnet synchronous motor based on space vector pulse width modulation(SVPWM)is studied.Firstly,the control strategy of PMSM is summarized,the development of direct torque control and the research status are elaborated,the basic structure and working principle of PMSM are introduced,and the mathematical models of PMSM in different coordinate systems are established.Secondly,the principle of direct torque control of permanent magnet synchronous motor is elaborated,the simulation model is built,and the simulation results are analyzed in detail.SVPWM is introduced to solve the shortcomings of traditional DTC with large torque and flux linkage ripple.Compared with the traditional direct torque control method,the direct torque control based on SVPWM has a constant switching frequency,which improves the problem of large torque and flux linkage ripple.In view of the influence of stator resistance variation on the system at low speed,an on-line stator resistance estimator is added to solve the problem of poor low speed performance of the system.Then,in order to take into account both rapidity and stability,and further reduce the problem of large torque and flux linkage ripple,deadbeat control is added.Deadbeat predictive control is combined with direct torque control based on SVPWM,deadbeat controller is established and the deadbeat voltage control rate is deduced.A closed-loop flux linkage observer is constructed to estimate the flux.A current predictive observer is added to eliminate the delay caused by calculation time and sampling period,which ensures the control accuracy of deadbeat direct torque and flux linkage control.The deadbeat control of torque and flux linkage is realized at constant switching frequency,which retains the rapidity of direct torque control and enhances the stability of the system,further reducing the torque and flux linkage ripple.In order to reduce the large torque ripple caused by low sampling frequency,a more precise current and flux observer model is used to ensure the accuracy of the torque control in deadbeat direct torque control with different sampling frequencies.Finally,the simulation model of the system is built in MATLAB/Simulink to validate the proposed method.The simulation results show that deadbeat predictive control has obvious advantages in restraining torque and flux linkage ripple,which verifies the correctness and feasibility of this method.