Research On Sensorless Control Strategy Of Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor(PMSM)are widely used because of their simple structure,low rotor loss,and high reliability.The accurate acquisition of motor speed and rotor position information determines the control performance of PMSM.In some application areas,position detection sensors have many drawbacks,so the research on sensorless control technology has emerged.In this paper,the position sensorless control technology of PMSM in the middle-high-speed and low-speed operation stage is researched and simulated experiment analysis.Specifically include the following:First,the structure and characteristics of PMSM are introduced,and their mathematical models in three coordinate systems are derived,and the basic principles of PMSM vector control and space vector pulse width modulation technology are explained in detail.A simulation model of vector control is built in Matlab/Simulink for simulation research.Secondly,when the motor is in the middle and high speed operation stage,the application of sliding mode observer in the position sensorless control of PMSM is studied.Aiming at the high frequency chattering problem of sliding mode observer and the insufficient accuracy of rotor position and speed observation,an improved sliding mode observer is proposed,a new piecewise function is designed as the switching function and the power approach is introduced.The law effectively suppresses the high-frequency chattering problem of the system.At the same time,the phase-locked loop estimates the rotor position and speed link,and adds the link to eliminate the influence of speed change,which further improves the observation accuracy of the sliding mode observer.The simulation verifies the feasibility and effectiveness of the improved sliding mode observer.Then,when the motor is in the low-speed operation stage,a position sensorless control strategy based on the pulsating high-frequency voltage signal injection method is studied.Aiming at the problems of phase delay and insufficient observation accuracy caused by the use of filters in the pulsed high-frequency voltage signal injection method,an improved pulsed high-frequency voltage signal injection method is used to directly control the high frequency in the two-phase stationary coordinate system.The response current is extracted and then demodulated,eliminating the need for band-pass filters,improving observation accuracy and simplifying the calculation process.The simulation results show that the improved control strategy can accurately observe the rotor position and has better observation performance.Finally,a PMSM sensorless control system with TMS320F28335 as the main control chip was built,and the sensorless control algorithm program was written and experimentally debugged.On this basis,experimental demonstration and theoretical analysis were carried out to verify The superiority and accuracy of the proposed improvement strategy.