Research On Rotor Position Estimation Of PMSM Based On Sliding Mode Observer

Permanent Magnet Synchronous Motor has many advantages such as high reliability,high operating efficiency,low loss,simple and flexible design,and is widely used in many transmission fields such as metallurgy,petroleum,chemical,and intelligent buildings..In recent years,high-performance position sensorless control technology has had an important impact on improving the economics of PMSM control systems,improving system reliability,and expanding system applications.However,the problem of low rotor position estimation accuracy and slow rotor position tracking speed directly affects the dynamic speed regulation performance of the PMSM sensorless control system.Aiming at this difficulty,this paper proposes a rotor position estimation method based on dual-line PLL using sliding mode current observer to improve the accuracy of rotor position estimation of permanent magnet synchronous motor.In this paper,the mathematical model of permanent magnet synchronous motor in natural coordinate system,α-β two-phase stationary coordinate system and dq two-phase rotating coordinate system is established.The different vector control strategies of permanent magnet synchronous motor are compared and analyzed.The principle of SVPWM is expounded..Then,based on the sliding mode variable structure control principle,the mathematical model of the sliding mode current observer is established.The rotor position estimation method based on extended back electromotive force is proposed.The PMSM rotor position estimation system based on sliding mode observer is designed and the Matlab is built./Simulink simulation model for verification analysis of rotor position estimation results.Next,for the inherent jitter and phase lag of rotor position estimation,the traditional sliding mode current observer is improved,and an improved method based on SRF-PLL rotor position estimation is proposed.The result can effectively suppress the jitter and reduce the phase lag..Then,for the contradiction between the dynamic response speed and the filtering performance of SRF-PLL rotor position estimation,a new filter and rotor position estimation method based on dual-line PLL is designed.The comparison results show that the improved system has faster Dynamic response speed,better filtering performance and higher rotor position estimation accuracy.Finally,the effectiveness and superiority of the proposed rotor position estimation method are verified by Matlab/Simulink simulation experiments.The semi-physical experiment system of permanent magnet synchronous motor based on RT-LAB is further built.The experimental results also prove that the proposed method can effectively improve the estimation accuracy of PMSM rotor position.