Research On Sensorless Control Strategy Of Permanent Magnet Synchronous Motor

As a high-efficiency electromechanical equipment in the field of modern motor drive,permanent magnet synchronous motor has high requirements on the control system.In order to improve the control accuracy,it is necessary to utilize more efficient control means while simplifying the structure of the motor.Position sensor plays an important role in improving motor control accuracy,but it also increases the cost and maintenance costs of the motor.The sensorless position control strategy of permanent magnet synchronous motor can effectively reduce the overall cost of the motor and obtain higher control precision.In this paper,a complete mathematical model of the permanent magnet synchronous motor is established to realize the high-performance control mode of the permanent magnet synchronous motor: vector control and direct torque control.When analyzing the parameters related to the rotor position in the vector control mode,the rotor position is estimated by using the variables related to the rotor position in the mathematical model of PMSM,and the sensorless control strategy of PMSM based on the fundamental wave mathematical model is realized by combining the sliding mode observer and model reference adaptive control.However,the position estimation algorithm based on mathematical model of permanent magnet synchronous motor will be affected by the low SNR signal at low speed.In order to improve the estimation accuracy of the rotor position and improve the running performance of low-speed motors in the extended speed range,the way of high frequency current injection is used to estimate rotor position,the accuracy of the rotor position calculation has been enhanced.At the same time,the effectiveness of the proposed sensorless control method has been proved by MATLAB simulation.Finally,this paper adopts TMS320F28335 DSP chip of TI company to design the software and hardware of sensorless control system of permanent magnet synchronous motor,and realizes the functions of initial rotor position detection,rotor speed and position estimation,speed adjustment,overvoltage and undervoltage protection.