Abstract: Traditional rotor flux observers cannot accurately estimate rotor flux due to influence of DC disturbance and harmonic disturbance, and then sensorless control method of permanent magnet synchronous motor(PMSM) based on rotor flux cannot accurately estimate rotor position. In order to solve the above problem, a sensorless control strategy for PMSM of scraper conveyor based on third-order generalized integral flux observer(TOGIFO) was proposed. By introducing the TOGIFO, high-order harmonic component can be effectively suppressed, and DC component in rotor flux can be completely eliminated in steady state without amplitude attenuation and phase delay of fundamental wave, so as to accurately estimate rotor flux and improve accuracy of rotor position estimation. The simulation results verify correctness and effectiveness of the control strategy.