Research On Model Predictive Control Scheme Of Permanent Magnet Synchronous Motor

With the upgrading of power electronic devices and the rapid development of digital signal processing technology,the control performance of AC electric drive system has surpassed that of DC electric drive system.As one kind of AC motors,permanent magnet synchronous motor has been widely used because of its small size and high power density.Since the advent of various high microprocessors with high computing power,model predictive control has been gradually applied to the field of motor control.In view of its simple algorithm principle,multivariable constraints and good dynamic performance,model predictive control has been regarded as the third generation of new motor control strategy after vector control and direct torque control.In this paper,the internal PMSM is taken as the research object,and the MPC scheme is deeply studied.Firstly,the structure characteristic of PMSM is introduced.Based on the principle of coordinate transformation,the mathematical models of internal PMSM are established in three different coordinate systems.Then,the topology of three-phase two-level inverter is introduced,and the voltage vectors generated by the inverter are summarized.In order to use the MPC to control PMSM,the basic principle of MPC is also introduced.Secondly,the model predictive current control(MPCC)of PMSM is studied.The single vector MPCC and dual vectors MPCC based on duty cycle control are introduced respectively.Then an improved dual vectors MPCC based on vector action time is introduced.The finite control set of the control scheme is expanded,and the action time of two voltage vectors is allocated by minimizing the steady-state current error to reduce the current ripple.In order to verify the effectiveness of the algorithm,the simulation model is built to verify the three MPCC schemes.Thirdly,the model predictive speed control(MPSC)scheme of PMSM is studied.This paper first introduces the traditional MPSC scheme,and then designs a fuzzy controller on the basis of the traditional MPSC scheme.Through the direct control of the acceleration,the dynamic speed curve of PMSM is finally designed as S-shaped curve,which can make the motor acceleration change slowly in the starting and stopping stages of the motor,so as to make the acceleration change slowly to reduce the impact and vibration caused by torque mutation.In order to verify the effectiveness of the two PMSC schemes,the simulations are carried out respectively.Finally,based on the experiment platform of the laboratory,the above MPC schemes of PMSM are tested,and the accuracy and feasibility of the control scheme are verified.