Research On Finite Set Model Predictive Control(FCS-MPC) And Torque Ripple Suppression Of Induction Motor

As the rapid development of economy and society,the issues of energy pinch and environmental pollution highlights.Vehicle industry,as a major emitters of green house gas and main energy consumer,has been on the way gradually to the new energy vehicles,which is clean,safe and efficient.The dynamic performance and operational stability are closely related to the core electric drive system,as a result,the topic of increasing the performance of electric drive system has gained great concern from academic world.Compared with PMSM,IM deficiencies in efficiency and power density,but it wins out in simple structure,low manufacturing cost,mature manufacturing method and reliable operation.Consider all this,the IM drive system is applied widely in the power chain of new energy vehicle.As the proposal of FOC,the speed governing performance had been improved greatly,further more,the proposal of DTC show us the possibility of further promotion for IM drive systems.MPC,as the third control strategy,had drawn great attention in high performance electric drive field.Moreover,the discreteness of the output voltage vector of the inverter provides a natural condition for the implementation of finite set model predictive control(FCS-MPC).The FCS-MPC make full use of inverter's discreteness,besides,the control method of this system is multiplicity,and it's more transplantable and better in dealing with nonlinear constraints.There's still room for improvement in FCS-MPC system,especially in optimal selection of voltage vector,operational simplification and torque ripple suppression.The main research work of this paper is embodied in the following aspects:1)Based on the mathematical model and discrete state equation of induction motor,the basic principle of MPC were introduced,and the dynamic and static performance of the model predictive control are discussed.2)Aiming at the problem that fewer output voltage vectors and larger electromagnetic torque ripple when two-level inverters are put into use,a control set expansion scheme based on virtual voltage vector is proposed,which realizes the suppression of harmonic and torque ripple of stator current and improves the stability of the system.3)The increase of alternative voltage vectors in control set increases the computational pressure of predictive control.Therefore,a simplified method of voltage vector selection is proposed,which improves the efficiency of the algorithm.4)On the basis of extended control set,duty cycle control is introduced to extend single vector model predictive control to double vector model predictive control,which further improved the operating performance of the control system.5)Based on MATLAB/Simulink simulation model and laboratory simulation experiment platform,the proposed model predictive control scheme is verified by simulation and experiments.Although the engineering application performance of the proposed FCS-MPC based on virtual vector still needs more comprehensive experimental verification,the research is still theoretically valuable to the development of FCS-MPC.