High-Frequency Signal Injection Method Based on Cascaded Notch Filter for PMSM Position Sensorless Predictive Control

The high-frequency pulsating voltage injection method is widely employed in sensorless control of permanent magnet synchronous motors (PMSMs). This study proposes an improved position error extraction strategy based on a cascade notch filter (CNF), enhancing estimation robustness during speed transients. The proposed method replaces the conventional band-pass filtering (BPF) by directly processing the $\hat q$ -axis current, with inherent attenuation of second-order harmonics. Further, by integrating this approach with ultra-local-based model predictive current control (UL-MPCC), this approach achieves superior dynamic performance. The effectiveness of the proposed method is verified by experiments with a conventional pulsating signal injection method.