Research On Direct Torque Control Strategy Of Permanent Magnet Synchronous Motor For Vehicle Driv

With the development of science and technology,electronic power technology and its control theory technology are becoming more and more mature,and permanent magnet synchronous motors are increasingly used in vehicle drive motors.Due to the influence of the direct torque control control strategy(DTC)hysteresis controller of the permanent magnet synchronous motor and the constant value of the stator flux linkage,the torque fluctuation of the control system is relatively large and the efficiency is low.Therefore,this paper takes the direct torque control strategy of permanent magnet synchronous motor as the research object,and proposes an adaptive direct torque control algorithm for the stator flux linkage to reduce its torque ripple and improve the efficiency of the vehicle drive control system.First,the hysteresis direct torque control strategy is studied,and the control system simulation model is built.The simulation results show that the torque fluctuation of the hysteresis direct torque control is relatively large.Aiming at the problem of large torque fluctuations,a direct torque control strategy based on space voltage vector modulation(SVMDTC)is proposed,and it is researched and analyzed.The space voltage vector module is used to replace the hysteresis voltage switch table to reduce the hysteresis.The torque fluctuation of the loop DTC control system,the simulation results show that compared with the hysteresis DTC control strategy,the torque fluctuation of the SVM-DTC control strategy is significantly reduced.Then,the given stator flux linkage for the SVM-DTC control system is constant,which may lead to lower efficiency of the motor drive system.The maximum torque current ratio(MTPA)control method of the direct torque control system is adopted,and the permanent magnet synchronization is used.The relationship between the motor current,torque,and flux linkage is used for adaptive direct torque control of the stator flux linkage.The given stator flux of the control strategy can change according to the change of load torque.By comparing the torque fluctuation and the amplitude of the stator current,it shows that the stator flux adaptive direct torque control can not only maintain the original SVM-DTC control.With low torque ripple,it can effectively reduce the stator current under constant torque and improve the working efficiency of the vehicle drive control system.Finally,build the NI PXI hardware-in-the-loop simulation experiment platform,use STM32F103 motor controller and Lab VIEW software to carry out HIL experiment on the stator flux linkage adaptive direct torque control system,and carry out the control system software development and design to verify the validity and effectiveness of the algorithm.stability.The motor bench experiment platform was built to carry out the bench experiment of the permanent magnet synchronous motor direct torque control system.The experimental results show that the stator flux adaptive control system can effectively improve the working efficiency of the drive control system.