Research On Sensorless Vector Control System Of Permanent Magnet Synchronous Motor Based On MRAS

Pure electric vehicles are the development direction of my country’s automobile industry formulated in accordance with national conditions.The core of electric vehicles is the drive motor,and its reliability is very important to electric vehicles.Permanent magnet synchronous motors have become the first choice for driving motors with their excellent performance.Field Oriented Control(Vector control(FOC))is the most effective control method for electric vehicle motors.The rotor position sensor needs to be used to obtain the rotor position of the motor.However,the rotor position sensor will reduce the reliability of the system and increase the system cost.Therefore,this article conducts an in-depth study on the sensorless FOC method of permanent magnet synchronous motors.This article first introduces the structure types of permanent magnet synchronous motors,and then introduces several main vector control methods and the current research status of position sensorless.According to the principle of coordinate transformation,mathematical models of permanent magnet synchronous motors are established in different coordinate systems,and SVPWM control theory is analyzed in detail.Aiming at the problems of permanent magnet synchronous motor rotor position sensor,the sensorless technology based on Model Reference Adaptive System(MRAS)algorithm is studied and verified by simulation analysis.The traditional MRAS algorithm is susceptible to the changes of motor parameters,and the stator resistance changes will cause deviations between the speed estimation and the rotor position estimation.An improved MRAS algorithm that can identify the speed and stator resistance at the same time is proposed.The simulation results show that the improved MRAS algorithm effectively reduces the influence of the stator resistance on the speed and improves the speed identification accuracy.In view of the sudden load changes caused by electric vehicles due to road conditions,the traditional speed loop PI regulators are difficult to coordinate,anti-interference ability and robustness.The simplified first-order auto disturbance rejection regulator is substituted for the PI regulator,combined with the improved MRAS algorithm.Motor control performance.The simulation results show that compared with the traditional MRAS field-oriented control algorithm,the improved MRAS field-oriented control algorithm based on the active disturbance rejection controller has better dynamic response and anti-interference ability.The system experiment platform with the STM32F302 chip as the control core was built,and the hardware circuit design and software design of the driver board were completed.Finally,the researched position sensorless algorithm was verified by related experiments.Finally,the system experiment platform with the STM32F302 chip as the control core was built,and the hardware circuit design and software design of the driver board were completed.Finally,the relevant experimental verification of the researched sensorless algorithm was carried out.