A Novel Finite Position Set Phase-Locked Loop Strategy for PMSM Position Estimation With High-Precision and Low Computational Burden

In pursuit of improving both the estimation accuracy and computational efficiency of sensorless control technology for a permanent magnet synchronous motor, this article proposes a novel antiharmonics finite position set phase-locked loop (AHFPS-PLL) strategy with high-precision and low computational burden. First, the conventional phase-locked loop (PLL) and finite position set phase-locked loop (FPS-PLL) methods are outlined briefly. Subsequently, a mathematical analysis is conducted to assess the adverse effects of harmonic disturbances on the FPS-PLL. After that, this article proposes a novel cost function considering harmonics caused by lumped disturbances to improve the robustness of the FPS-PLL to harmonic disturbances and enhance the position estimation accuracy. During the iteration phase, an innovative optimal position-searching strategy is devised. This strategy relies on the position arctangent quartile method and Taylor expansion iteration to efficiently approach the vicinity of the rotor position in the shortest possible time. The convergence radius and theoretical precision of the proposed AHFPS-PLL strategy are given. This method eliminates the proportional-integral controller applied in the conventional PLL, thereby reducing the complexity of parameter tuning. The AHFPS-PLL, as presented, achieves optimal rotor position determination in just two iterations, surpassing the accuracy of the FPS-PLL notably, while preserving superior dynamic. Finally, the validity of the proposed AHFPS-PLL strategy is experimentally confirmed.