Sensorless Algorithm of Permanent Magnet Synchronous Linear Motor Based on Super- Twisting Sliding Mode Observer with New Adaptive Strategy

An innovative adaptive strategy is applied to the super-twisting sliding mode observer (STSMO) for permanent magnet synchronous linear motors (PMSLM), addressing the issue of significant nonlinear variations in the observed back electromotive force (back-EMF) amplitude during uniform acceleration when using a fixed-parameter STSMO. The stability of the proposed method and the reasons behind the nonlinear behavior of the STSMO under fixed parameters are analyzed. A normalized orthogonal phase-locked loop (PLL) is employed to extract velocity and position. Simulation results demonstrate that the back-EMF observed by the new adaptive algorithm during uniform acceleration closely aligns with theoretical values, and the sensorless algorithm exhibits excellent tracking performance.