Optimization Of Drive Motor Response Speed During Two Gear AMT Shift

With the strong support of new energy industry policy,pure electric vehicle has become an important road of China’s automobile industry.In order to improve the endurance and climbing ability of electric vehicles,electric vehicles equipped with two speed transmission are becoming a research hotspot.In order to better meet the shift requirements of two speed transmission and improve the response speed of motor speed and torque,the vector control technology of permanent magnet synchronous motor(PMSM)will be studied in this paper.The specific contents are as follows:(1)First of all,this paper creates α-β And PMSM mathematical model in threephase natural coordinate system,the space vector pulse width modulation(SVPWM)method is developed,and the vector control system framework of motor is developed by combining the two.(2)In terms of control strategy,according to the shift time demand of two speed transmission,in order to shorten the response time of speed and torque of drive motor,this paper adopts the maximum torque current ratio control strategy MTPA.In the aspect of its engineering realization,it is proposed to use the segmented curve fitting method to solve the mathematical calculation of current distribution,which further reduces the calculation difficulty and ensures the calculation accuracy at the same time.(3)Combining MTPA with flux weakening control algorithm,a stator current distribution method in full speed domain is developed.Aiming at the current control algorithm of field weakening zone 1 and field weakening zone 2,a voltage feedback compensation method acting on quadrature axis current is proposed;Compared with the traditional single current field weakening control,the field weakening strategy in this paper makes use of the monotonic variation of the quadrature axis current in the field weakening process,and can correctly switch the field weakening interval by matching the corresponding direct axis current.This method combines the current distribution of the maximum current circle and the maximum torque voltage ratio curve of mtpv,which improves the operating speed range of the motor and the utilization of stator current.Compared with the traditional voltage decoupling control and internal mode decoupling control,the accuracy of the stator current decoupling control is improved.(4)The visual model is developed and simulated in MATLAB \ Simulink environment.The results show that the method in this paper shortens the response time of speed and torque,expands the speed range,improves the control accuracy of current and torque,and improves the anti-interference ability of speed controller.At the same time,the motor speed regulation under shift condition is simulated,and the results show that the response speed of the motor meets the needs of the two gear AMT upshift and downshift process.(5)Finally,in order to verify the feasibility of the engineering implementation of the motor control algorithm studied in this paper,the underlying driving software and motor control algorithm such as FTM,ADC and PDB are developed for NXP microcomputer S32K142,and the motor speed regulation test is carried out to verify the correctness of the control algorithm of permanent magnet synchronous motor in this paper.