Low Computational Estimated Position Error Compensation and Phase-locked Loop Normalization for PMSM Sensorless Control

This paper analyzes the back-electromotive force (EMF) phase lag caused by the introduction of the sigmoid function and deduces the estimated position error compensation formula. Simultaneously, in view of the bandwidth change of the conventional phase-locked loop (PLL), the necessity of normalizing the PLL is analyzed. However, the computation required by these two algorithms takes a long time on the digital signal processor (DSP). To solve this problem, this paper proposes a low-computational estimated position error compensation algorithm and a low-computational PLL normalization method, which save one division, one arctangent, and one square root operation. They are of great significance for high switching frequency or the application of complex algorithms. To verify the effectiveness and feasibility of the proposed algorithm, experiments are carried out on a surface-pasted permanent magnet synchronous motor (PMSM).