Research On Predictive Torque Control Of Permanent Magnet Synchronous Motors With Low Torque Ripple

The complex working environment of modern industry puts forwar d more and more complex constraints on the Permanent Magnet Synchronous Motors(PMSMs)control system.Therefore,the limited control set model predictive control(MPC)that is easy to achieve multi-objective control and multiconstraint conditions has gradually entered the field of motor control.This paper mainly focuses on the problem of large torque ripple by the single vector Model Predictive Torque Control(MPTC)of the PMSMs control system,by improving the prediction robustness of the prediction model and using the torque ripple suppression strategy to improve the steady-state torque ripple.Combining the principle of MPC and the mathematical model of PMSM,the discrete predictive mathematical model of MPTC is deduced.On this basis,the related design and simulation realization of single vector MPTC are realized,and the problem of its torque ripple has been found.It lays a foundation for the subsequent improvement of the design of torque ripple-related control strategies and provides a control performance control group.Starting from the discrete prediction model of torque and flux,the sensitivity of different parameters to prediction errors is analyzed,and the effect of weighting factors on the steady-state control performance of torque and flux is known from simulation analysis.In order to solve the influence of paramet er sensitivity on the steady-state performance of the PMSMs control system,a single vector model predictive flux control(MPFC)with improved robustness is designed,which updates inductance value of the predictive model and use current ESO compensating the current prediction error only based on the sampled current and position information,thereby predicting the d and q flux,does not rely on the motor parameters of the prediction m odel,and the torque is converted into the flux without weighting factors.Aiming at the problem of torque ripple large in single vector MPTC,the main reason for torque ripple large is analyzed theoretically,and then two torque ripple suppression strategies are designed for the reason of torque ripple large,the MPTC based on the optimizing value function(JO-MPTC)and improved double vector MPTC(ND-MPTC).The JO-MPTC obtains the optimal voltage vector through optimizing the value function,and uses the space vector modulation technology(SVM)to solve the output voltage vector deviation;the ND-MPTC uses torque and flux slope obtains each voltage vector and its act ion time,and then the optimal voltage vector and its action time are obtained by enumerating the flux control performance in consideration of the value function,which not only reduces the output voltage deviation but also makes the switching point non-fixed.Experiments have verified that the single vector MPTC,the strategy of improving robustness and the strategy of torque ripple suppression,among which the strategy of improving robustness can run stably,and the effectivenes s of the two torque ripple suppression strategies have been analyzed in depth.It is different from the control performance in the experiment.