Research On Torque And Flux Control Of Permanent Magnet Synchronous Motor Based On Deadbeat Theory

Vehicles occupy an important position in people’s daily life.Compared with fuel vehicles,new energy vehicles have the advantages of zero emission and no pollution,which are more in line with the requirements of low-carbon economy.The permanent magnet synchronous motor(PMSM)has become the first choice for the drive motor of new energy vehicles because of its simple structure,large starting torque,so the research on the control method of PMSM is of profound significance.The traditional control methods of PMSM include direct torque control(DTC)and field oriented control(FOC).DTC directly controls the electromagnetic torque and stator flux of the PMSM,which has good dynamic performance and simple control structure,but due to the existence of hysteresis loop controller and off-line switching table,the torque ripple of the PMSM is large.FOC uses the theory of coordinate transformation to decouple the stator current,realizes indirect control of the electromagnetic torque and stator flux by controlling the current component.The control algorithm has high control accuracy but slow dynamic response.In order to obtain the good control performance of PMSM,this thesis mainly does the following work to solve the above problems:Firstly,the basic theory of PMSM is briefly described in this thesis.First,the mechanical structure of PMSM is introduced.Second,several coordinate systems and coordinate transformation methods used in the thesis are described.Third,the mathematical model of PMSM in the three-phase stationary coordinate system is established based on its structural principle.Secondly,the traditional DTC algorithm is researched in this thesis.First,the basic principle of DTC algorithm is introduced and the concept of voltage vector is introduced.Second,the control system structure of the traditional DTC algorithm is introduced,in which the working principle of the hysteresis loop controller,the process of creating the offline switching table are explained in detail.Third,the simulation model of this control algorithm is built on the MATLAB/Simulink simulation platform.Through the analysis of the simulation results,it can be known that the hysteresis loop controller and the offline switching table in the control system are the main reasons for the low control accuracy of the DTC algorithm.Thirdly,the FOC algorithm and electromagnetic torque and stator flux control algorithm based on space vector modulation(SVM)are researched in this thesis.First,the basic principle of FOC is introduced,and its control system structure is described in detail.Second,aiming at the problems of low control accuracy of DTC algorithm and slow dynamic response of FOC,a direct electromagnetic torque and stator flux control algorithm based on space vector modulation(SVM-DTFC)is introduced.Third,the simulation models of two control algorithms are built on MATLAB/Simulink simulation platform.The simulation results show that the SVM-DTFC algorithm is better than DTC algorithm in control accuracy and faster than FOC algorithm in dynamic response.Then,the deadbeat direct electromagnetic torque and stator flux control algorithm(DB-DTFC)is researched in this thesis.First,the basic principle of the traditional DB-DTFC algorithm is introduced.A new DB-DTFC algorithm is proposed for the problem that the process of solving the reference stator voltage by the traditional DB-DTFC algorithm is more complicated.Second,the control structure of the new DB-DTFC algorithm is introduced,the workflow of the control system is described in detail.Third,the new DB-DTFC algorithm simulation model is built on the MATLAB/Simulink simulation platform.The simulation results show that the proposed new DB-DTFC algorithm has improved control accuracy and dynamic response compared with the SVM-DTFC algorithm.Finally,a physical experiment platform of PMSM control system is built in this thesis.First,the design principle of the hardware circuit in the experimental platform is introduced.Second,the automatic code generation function of MATLAB and its specific implementation process are introduced.Third,the FOC algorithm is tested on the experimental platform,the experimental results verify the effectiveness of the control system.