Research On Optimal Control Of PMSM Based On Sliding Mode Observer And Predictive Control

Permanent magnet synchronous motor(PMSM)has been widely used in many fields for its high efficiency,high power density and high power factor.At present,the widely used high performance PMSM control technology mainly includes vector control and direct torque control.The direct torque control regards electromagnetic torque and stator flux as a direct control target,no current regulator and coordinate transformation.It has the advantages of simple structure,fast dynamic response and so on.However,the direct torque control has the disadvantage of large torque ripple,so it is necessary to have a high switching frequency in order to ensure its steady state performance.In order to further improve the performance of direct torque control system,two optimization control methods are proposed in this paper based on the traditional predictive torque control.First of all,in order to reduce influence of the motor parameters perturbation to the deadbeat direct torque control(DBDTC)calculation of the reference voltage vector,this paper proposes a deadbeat torque control method based on sliding mode disturbance observer(DBDTC+SMDO).This method observes the reference voltage change caused by the perturbation of the motor parameters(stator phase resistance,inductance and permanent magnet flux)by constructing d,q axis SMDO.Using the observed values to identify and compensate the motor parameters perturbation not only greatly reduces the influence of the motor parameter perturbation to the calculation of the reference voltage vector,but also improves the robustness of the DBDTC to the parameter perturbation.Secondly,in order to reduce the computation of traditional model predictive torque control(MPTC)and eliminate the weight coefficient between the torque and flux linkage,this paper presents a PMSM MPTC method based on reference voltage tracking error(MPTC+RVTE).This method uses the DBDTC control principle to calculate the reference voltage vector for the next cycle.According to the reference voltage vector where the sector position to narrow the optimal voltage vector selection range,so as to achieve the purpose of reducing the amount of calculation.And on the basis of it,the cost function of the traditional torque error and the flux error is replaced by the cost function of voltage error,which eliminates the weight coefficient design of the traditional MPTC and simplifies the system structure.This paper not only applies the MPTC+RVTE method to single vector MPTC,but also to double vector MPTC.At last,DBDTC+SMDO and traditional DBDTC,MPTC+RVTE and traditional MPTC were simulated and experimented respectively.The simulation and experimental results show the correctness and effectiveness of the proposed method.