Research On Improved Predictive Torque Control System For Permanent Magnet Synchronous Motor

Permanent magnet synchronous motors are widely used in AC speed regulation systems because of their high power density and fast response speed.Compared with the vector control method of permanent magnet synchronous motors,the direct torque control method has the advantages of torque direct closed loop,faster response speed and simple structure,which makes the direct torque control method a research hotspot in the field of permanent magnet synchronous motor drive control.In view of the problem of large torque ripple in direct torque control,from the perspective of torque ripple suppression,the model predictive control algorithm is introduced into the direct torque control system for in-depth research.First,the mathematical model of the permanent magnet synchronous motor in different coordinate systems is derived through the transformation of different coordinate systems.Combining the analysis of space vector technology modulation technology and direct torque control algorithm,the direct torque control method is found in principle causes of large torque ripple of lower permanent magnet synchronous motor.Secondly,the principle of model prediction is introduced,and the model prediction algorithm is introduced into the motor model,thereby the predictive torque control algorithm of the permanent magnet synchronous motor is established.The simulation model of the predictive torque control algorithm of the permanent magnet synchronous motor is built and the simulation results are given.The simulation results show that the torque ripple suppression effect of the predictive torque control algorithm is better than the direct torque control,but at the same time the predictive torque control algorithm has the problems of large amount of calculation and excessive control.Then,for the problem of large calculation amount and excessive control in the torque control algorithm,the torque ripple is still high.The improved predictive torque control algorithm that combines fast voltage vector selection and duty cycle is proposed,which effectively solves the problem of large calculation and excessive control of the algorithm in each sampling period,while the weight coefficient in the value function optimized the algorithm is eliminated.Finally,the simulation model of the improved predictive torque control algorithm is built,and its simulation results are compared with the simulation results of the direct torque algorithm and the predicted torque control algorithm.Finally,on the basis of theoretical derivation and simulation verification,the DSP28335 is used as the core control chip,the control circuit and motor power drive circuit are designed and the experimental platform of the permanent magnet synchronous motor control system is built.The effectiveness of the improved predictive control algorithm to optimize torque ripple is verified through experiments.