Multi-vector Model Predictive Torque Control Of Permanent Magnet Synchronous Motor System

Permanent magnet synchronous motor(PMSM)has the advantages of simple structure,high control precision and wide speed range.It has been widely used in elevator traction and oil drilling.In recent years,in order to improve the dynamic performance of the motor system,Model Predictive Torque Control(MPTC)has been applied to permanent magnet synchronous motor control systems.The traditional double vectors model predictive torque control uses an active vector and a zero vector to synthesize voltage vector in one control cycle to control the motor system and to achieve a control effect superior to the traditional single vector model predictive torque control strategy.However,due to the limitation of zero vector control performance,the traditional double vectors model predictive torque control cannot meet the increasingly high torque and flux control requirements of permanent magnet synchronous motor systems.Aiming at the problem of insufficient torque control performance of traditional double vectors model predictive torque control strategy,this paper proposes an improved double vectors model predictive torque control strategy for permanent magnet synchronous motor system.In this paper,the new difference parameters m and n are defined,and the optimal vector combination is obtained with a small amount of calculation by a relatively intuitive look-up table method.Then,the duty cycle is calculated based on the difference parameter,and the inverter switching pulse is generated to realize the control of the permanent magnet synchronous motor system.The experimental results show that compared with the traditional double vectors model predictive torque control,the improved double vectors model predictive torque control proposed in this paper can effectively suppress the torque and flux ripple of permanent magnet synchronous motor,and the amount of calculation of the system and the switching loss of the inverter have been considered.In order to achieve better flux control performance,this paper proposes an improved three vectors model predictive torque control strategy for permanent magnet synchronous motor systems.By using the parameters of the improved double vectors model predictive torque control,adding the three-vector selection table,an active vector u_a is flexibly added based on the traditional double vectors model predictive torque control strategy;the duty of the three vectors is calculated based on the difference parameter,then the control of the permanent magnet synchronous motor system is realized by using three vectors in one control cycle.In this paper,the proposed strategy is verified by the 6kW permanent magnet synchronous motor experimental system.The experimental results demonstrate the feasibility and effectiveness of the improved three vectors model predictive torque control strategy.Finally,the paper compares the control performance between the traditional double vectors model predictive torque control strategy and the improved multi-vector model predictive torque control strategy.