Four Consecutive Samples Based Sensorless Control for PMSM Drives

Phase-locked loop (PLL) and frequency-locked loop (FLL) synchronization technology in permanent magnet synchronous motor (PMSM) has been paid attention to by many researchers. However, in the actual operation of PMSM drivers, harmonics and dc offsets are inevitable, which brings great challenges to the synchronization technology. To tackle this issue, this article proposes a novel four consecutive samples (4CS) based sensorless control algorithm for PMSM drives. The 4CS algorithm establishes the relationship between flux and its consecutive sampling signals, and it has inherent ability to suppress the influence of harmonics and dc offsets. Furthermore, the adaptability of 4CS is improved for better PMSM drive performance. The stability of the proposed 4CS algorithm is proven. Also, experimental results are provided to verify the efficacy of the proposed method.