Sensorless Control Based on Discrete Fractional-Order Terminal Sliding Mode Observer for High-Speed PMSM With LCL Filter

This article proposes a sensorless control method based on a fractional-order terminal sliding mode observer for high-speed permanent magnet synchronous motor (HSPMSM) with LCL filter. The LCL filter is used in the drive system to suppress high-frequency harmonics. First, an extended state sliding mode observer for the HSPMSM with LCL filter is proposed. A predictive correction discrete method based on Runge–Kutta is proposed for discretizing the extended sliding mode observer (SMO) to reduce the discretization error. Then, a fractional-order sliding mode surface and approaching law are proposed to increase the convergence speed and suppress the chattering present in traditional sliding mode observation. The discretization error, convergence, and chattering suppression performance of the proposed control strategy are analyzed. Compared to conventional SMO methods, the issue of sliding mode chattering is effectively addressed, enhancing the SMO control performance. Finally, experimental results comparing different methods verify the feasibility and effectiveness of the proposed method.