Duty Cycle Model Predictive Torque Control Of Permanent Magnet Synchronous Motor Based On Extended Voltage Vector

Under the background of industrial development in the new era,permanent magnet synchronous motors with energy efficient,high power and low loss have gradually become the vane of motor industry development.Facing the actual demand for energy conservationt,higher requirements are also put forward for the performance of permanent magnet synchronous motor AC servo system.The model predictive torque control strategy has received a lot of attention from researchers because of its simple principle and better torque output capability.However,this strategy still suffers from the problems of tedious weight factor adjustment,limited number of optional voltage vectors,poor steady-state performance and large computational effort.Therefore,it is of great significance to study the model predictive torque control strategy for permanent magnet synchronous motor to address the above problems.In this paper,the surface-mounted permanent magnet synchronous motor is taken as the research object,and a duty cycle model prediction torque control strategy based on the extended voltage vector is studied.Aiming at the problem that the model prediction torque control strategy has large torque and flux ripple and requires to design weight factor.Firstly,combining with the idea of duty cycle,this paper studies a duty cycle model prediction torque control strategy with eliminating weight factor,the stator flux and the electromagnetic torque are converted into equivalent active torque and reactive torque by instantaneous power theory.New cost function is designed to omit the tuning of the weight factor.Secondly,on this basis,a duty cycle model prediction torque control strategy based on extended voltage vector is studied in this paper,which increases the number of candidate voltage vectors by extending the voltage vector and optimizes the selection of candidate voltage vectors by using the fast vector selection method,so as to improve the steady-state performance of the control system and reduce the computational complexity.In order to verify the feasibility and effectiveness of the strategies studied in this parper,three strategies of the duty cycle model predictive torque control,the duty cycle model predictive torque control with eliminating weight factor,and the duty cycle model predictive torque control based on extended voltage vector,are simulated using MATLAB/Simulink simulation software and are experimentally researched on the two-level voltage source inverter-driven permanent magnet synchronous motor AC paired platform.Simulation and experimental results show that the duty cycle model predictive torque control with eliminating weight factor does not need to adjust the weight factor and has similar dynamic and steady-state performance as the duty cycle model predictive torque control.Compared with the duty cycle model predictive torque control with eliminating weight factor,the duty cycle model predictive torque control based on extended voltage vector has smaller torque and flux ripple in the steady-state operation of the motor,which improves the steady-state performance of the system.Moreover,this control strategy effectively simplifies the calculational effort.