Research And Implementation Of Torque Control Strategy Of Permanent Magnet Synchronous Motor For Electric Vehicle

With the increasing environmental pollution,the voice of green travel is getting higher and higher.Electric vehicles have become the first choice for people with their high operating efficiency,good starting acceleration performance and easy maintenance.Permanent Magnet Synchronous Motor(PMSM)has been widely used in the field of electric vehicles because of its advantages,such as light weight,good reliability and high power density and so on.According to the application scenario of electric vehicles,permanent magnet synchronous motors need to output large torque below the rated speed to meet the requirements of starting repeatedly and climbing of electric vehicles.When the electric vehicle reaches the rated speed,it needs to be able to output high speed to meet the requirements of overtaking and accelerate.In order to realize the full-torque fullpower stability control of PMSM of the electric vehicle,the full-speed range torque control strategy of PMSM based on the speed segmentation is designed on the basis of the traditional control strategy.The main contents of this paper are as follows:1.The physical model of PMSM,the basic principle of coordinate transformation and the mathematical model under different coordinate systems are studied.Then the advantages and disadvantages of the main control strategies of PMSM in different speed ranges are analyzed.A full-speed range torque control strategy based on torque calibration algorithm and dynamic gain current loop control algorithm is proposed for the deficiency of traditional control strategies.2.The off-line calibration algorithm of PMSM electromagnetic torque is studied.An off-line calibration algorithm for multiple linear regression electromagnetic torque based on speed partition is proposed to solve the problems of high cost and large computational complexity of real-time online calibration of the electromagnetic torque.By segmenting the full speed range of the motor,selecting different calibration coefficients at different speed points to calibrate the motor electromagnetic torque off-line,and finally achieving electromagnetic torque calibration in the full speed range.Furthermore,the algorithm is easy to be applied in engineering and has a small amount of calculation.3.In order to improve the control effect of the current loop of the permanent magnet synchronous motor in the whole speed range,this paper designs a dynamic current loop regulator algorithm based on speed partition,which can automatically adjust the current loop regulator parameters according to the real-time speed of the motor.By comparing the traditional current loop control algorithm and the dynamic gain current loop control algorithm Matlab/Simulink simulation results,the superiority of the dynamic gain current loop regulator algorithm in current dynamics and steady state control is proved.Finally,the electromagnetic torque off-line calibration algorithm and dynamic gain current loop control algorithm are verified and improved by bench test,and the effectiveness of the algorithm is proved.The actual driving experiment on the electric vehicle verifies the practical application value of the proposed algorithm.