Static-Errorless Position Estimation for Sensorless PMSM Drives With Enhanced Robustness Against the Full-Frequency Domain Disturbance

The back-electromotive force (BEMF) model-based position estimation is attractive for sensorless permanent magnet synchronous motor (PMSM) drives. However, the conventional method cannot ensure the robustness against the full-frequency domain disturbance, which results in the position estimation error. To address this problem, this article proposed a static-errorless position estimation strategy for sensorless PMSM drives. First, a second-order BEMF observer is proposed to achieve the bandpass characteristics for the simultaneous elimination of dc error and high-frequency noise. Second, a speed-adaptive notch filter-based phase-locked loop is presented to suppress the fluctuation caused by the medium-frequency harmonics. Compared with the conventional method, the studied static-errorless position estimation strategy shows strong robustness against disturbance in the full-frequency range. This ensures the finite-time convergence of position estimation. Finally, the studied algorithm is experimentally verified on a 4.4 kW ARM-based PMSM platform.