Permanent Magnet Synchronous Motor Model Predictive Torque Control Based On Duty Cycle

Permanent magnet synchronous motor has been widely used in aerospace,CNC machine tools and other high-performance speed control occasions.In the control strategy of permanent magnet synchronous motor,model predictive control has attracted wide attention because of its simple principle and easy handling of multiple control objectives.Model predictive control is divided into continuous control set model predictive control and finite control set model predictive control.Model predictive current control,model predictive flux control and model predictive torque control are included in finite control set model predictive torque control.In this dissertation,model predictive torque control(MPTC)is the main research object.In traditional MPTC,weight factor is used in cost function to balance the weight of different dimension control objectives,but the determination of weight factor needs repeated trial and error,and the workload is heavy.Although the model predictive torque control method with duty cycle link can reduce the fluctuation of torque and flux linkage,this method first chooses voltage vector,then calculates duty cycle,the voltage vector selected by this process cannot guarantee the global optimum,so duty cycle link cannot fully play its role.The difficulty of setting the weight factors and the duty cycle cannot fully play a role.This dissertation proposes a method based on the duty cycle optimization vector.In this method,when calculating the alternative vectors,the duty cycles of the torque and the flux are calculated respectively,aiming at the deadbeat of the torque and the deadbeat of the flux.By enumerating the possible combinations of the two duty cycles,the optimal vector is selected to replace the cost function in the traditional method,thus eliminating problem of weighting factor setting.By first calculating duty cycle and then selecting the optimal vector,the improved method solves the problem that duty cycle is difficult to play its role in traditional methods..The traditional method and the improved method are simulated and verified in MATLAB/SIMULINK.Through the experimental results,it can be concluded that the proposed improved method can eliminate the problem of the weighting factor and the problem that the duty cycle cannot function while maintaining the dynamic performance compared with the traditional method,and obtain better torque and flux control effect.