Traditional sliding mode observer-based rotor position estimation algorithms employ discontinuous control signals

low-pass filters

and phase-locked loop

which introduce chattering phenomena and position estimation errors. To suppress chattering

a novel sliding mode observer was proposed by adopting an integral nonsingular fast terminal sliding mode surface and designing a reaching law based on the sliding surface structure. By analyzing the position error transfer function of the phase-locked loop

the mechanism behind the position estimation error caused by the phase-locked loop was revealed. An position error estimation method based on an extended state observer was then designed. By integrating the extended state observer with the phase-locked loop

a position estimation algorithm with error compensation was constructed. A detailed analysis of its error transfer function theoretically proves that this compensation method can eliminate position estimation errors present during both dynamic and steady-state processes of the motor. Experimental results demonstrate that the error-compensated position estimation algorithm achieves 70% lower speed chattering than conventional methods

with position estimation errors reduced by 83.9% in steady-state operation and 72.7% during dynamic transients

ultimately enhancing system dynamic performance

rotor position estimation precision

and system robustness.