PMSM Model Predictive Direct Torque Control Based On Extended Voltage Vector

Since the traditional direct torque control(DTC)method of PMSM has the characteristics of less voltage vectors in the voltage vector table and fixed amplitude of the voltage vector in a single control cycle,it inevitably leads to larger torque ripple,which limits the use of DTC method in low speed operating conditions.Therefore,more and more attention has been paid to the reduction of torque ripple by increasing the voltage vector in voltage vector meter,introducing duty cycle calculation,and solving the problem of optimal voltage vector by model predictive control.In this paper,an extended non-zero basic voltage vector is introduced,aiming at the limitation of the traditional DTC method and the alternative voltage vector of model predictive DTC.Furthermore,two methods of predicting torque control by duty cycle model and duty cycle primary model are proposed.The former uses fuzzy control algorithm to adjust the weight coefficient in the objective function of the model predictive control in real time according to the magnetic linkage and torque errors,and uses the duty cycle calculation method based on the minimum principle of the objective function instead of the conventional torque deadbeat duty cycle calculation method.Compared the primary models predict torque control also based on the optional voltage vector extension,but calculation of duty cycle change,with no beat as a target for solving torque,then according to get the duty ratio of itself to the primaries,the optional voltage vector on the choice of voltage vector and its next duty ratio of magnetic chain forecast model,select the optimal voltage vector and its duty ratio.In addition,aiming at the error caused by the traditional method of calculating pure integral magnetic flux linkage,the high-pass filter is added to improve the estimation accuracy of stator flux linkage.In order to verify whether the two control strategies proposed in this paper can effectively reduce the flux linkage and torque ripple,simulation analysis and experimental verification are carried out respectively.Results show that the variable weight coefficient based on extended voltage vector space than the models predict torque control method and the duty ratio based on extended voltage vector primary models predict torque control method can effectively reduce the flux pulsation of the flux control effect,and duty ratio primary model prediction have better torque control torque control performance.