Research On Sensorless Control Of Permanent Magnet Synchronous Motor Based On High Frequency Signal Injection

Permanent Magnet Synchronous Motor(PMSM)is widely used in aerospace,ships,electric vehicles and other high-precision control fields due to its strong torque capability,high power density and high reliability.Mechanical sensors are usually used to obtain the position information of the rotor when the motor is running,which leads to the increase of the volume of the system,the reduction of reliability and the increase of maintenance cost.It also limits the normal operation of the system under harsh conditions or special occasions.Therefore,the sensorless control technology of the motor came into being,and quickly became the research hotspot in the field of motor control.In this paper,the interior permanent magnet synchronous motor is taken as the research object.Under the condition of low speed operation of the motor,the position sensorless control technology is studied from two aspects:improving the rotor position detection accuracy and system dynamic performance.Two methods of pulse high frequency signal injection and high frequency square wave signal injection are designed for position sensorless system,and finally verified by simulation.Firstly,this paper describes the research background of PMSM and the research status of sensorless control technology at home and abroad.The control method and strategy of PMSM are summarized,and then the mathematical model of PMSM is established in different coordinate systems.The core coordinate transformation of vector control is analyzed in detail,and the vector control system structure of PMSM with sensor is established.Then the vector control speed regulation system is constructed,and then the simulation model is established in Matlab/Simulink environment.The simulation analysis lays the foundation for further research on the sensorless vector control system.Firstly,this paper describes the research background of PMSM and the research status of sensorless control technology at home and abroad.The control strategy of PMSM is summarized,and then the mathematical model of PMSM under different shafting is established.The core coordinate transformation of vector control is analyzed in detail.Then the simulation model of PMSM vector control with i_d=0 is built in MATLAB/SIMULINK environment.Combined with the simulation analysis,it lays the foundation for further research on PMSM sensorless vector control system.Secondly,the mathematical model of PMSM under high frequency excitation is established,and the sensorless control system of PMSM injected by rotating high frequency signal is studied.Then,the rotor position information extraction process of pulsating high frequency signal injection method is deduced and studied,and the PLL rotor position tracking observer is designed.Finally,the two control schemes are simulated and compared by simulating various actual working conditions.Including the comparative study of the performance of the two systems under the same target speed,the simulation study of the motor speed mutation under the simulated actual working conditions,and the simulation comparison of the system when the disturbance load mutates.Finally,it is shown that under the condition of low speed operation of the motor,the two high frequency signal injection sensorless control systems show excellent speed tracking performance and position observation accuracy.Among them,the sensorless control system based on high-frequency square wave signal injection avoids the use of filters in the carrier signal separation process,improves the system bandwidth,reduces the phase shift of the estimated rotor position,and shows better speed tracking performance and rotor position observation accuracy under the same operating conditions.