High-Order Terminal Sliding-Mode Observer for Chattering Suppression and Finite-Time Convergence in Sensorless SPMSM Drives

Due to the advantages of strong robustness and fast convergence, the sliding-mode observer (SMO) is considered as an effective approach for sensorless surface-mounted permanent magnet synchronous motor (SPMSM) drives. However, the inherent chattering and none finite-time convergence are still challenging problems in SMO application. To address these problems, this article proposed a high-order terminal SMO (HOTSMO) for SPMSM position estimation. First, a terminal sliding-mode surface is designed to achieve finite-time convergence of state variables. Second, a high-order sliding-mode control law is presented to achieve chattering suppression. Compared with the conventional SMO, the studied HOTSMO can achieve high estimation accuracy without sacrificing strong robustness of SMO. The effectiveness of the studied scheme is experimentally verified on a 4.4-kW ARM-based SPMSM platform.