Study On Torque-Speed Mode Switching Of Permanent Magnet Synchronous Motor And Design Of Motor Controller

Assembling transmission in electric vehicle is one of the important ways to improve its power and economy.By virtue of the fast response characteristics of driving motor,the shift time can be shortened and the shift quality can be improved.In this process,the torque speed mode switching is required for the motor control method.At present,the control method of motor speed regulation by motor mode switching is more complex,and the speed regulation time is long and the overshoot is large.Aiming at the above problems,this paper studies the torque speed mode switching scheme of permanent magnet synchronous motor(PMSM)to improve the speed response speed and stability,and designs the hardware and software system of motor controller.The feasibility and effectiveness of the proposed scheme are verified by simulation and experiment.Main tasks as follows:(1)The field oriented control(FOC)algorithm of rotor field is studied.The sliding mode speed controller,current inner loop PI controller and space vector pulse width modulation(SVPWM)algorithm model are designed.The motor control system of speed mode and torque mode is built in the Simulink platform,and the control performance is verified by simulation.(2)The on-line switching method of motor control mode is studied.In order to improve the speediness and stability of the speed response,a control mode switching scheme with transition process is proposed.By precise control of the electromagnetic torque,when the motor speed reaches the target speed,the electromagnetic torque is exactly equal to the load torque.Build the simulation model of the switching scheme,and the simulation results show that in the simulation environment of speed up and speed down,the stabilization time decreased by 16.34% and 4.39% respectively,and the overshoot decreased by 93.33% and 93.28% respectively.(3)The application of TC275 chip in the motor controller is studied,the minimum system of the chip is built,and the drive configuration of related functions is completed.The chip is used as the main control chip to design a controller hardware system for 48 V / 500 w motors.Based on the parameter matching and device selection,the motor controller main circuit,control circuit and sampling circuit were designed,and the schematic diagram and PCB drawing were completed in Altium Designer software.At the same time,the software program of motor control mode switching method is designed.(4)Build the experimental platform,complete the function debugging and performance verification of the hardware system of the motor controller system.Based on the debugging results,the circuit design of the hardware system is improved.Then,based on the hardware system,the validity of the motor mode switching algorithm is verified.The experimental results show that the speed stabilization time is shortened by 15.7% and 3.5% respectively when speed is increasing,and the overshoot is reduced by 77.78% and 82.88% respectively when speed is decreasing.