Sensorless Control Strategy for Permanent Magnet Synchronous Motor Based on Adaptive Non-Singular Fast Terminal Sliding Mode Observer

The small effect of parameter variations on the sliding mode observer (SMO) and its robustness have been widely used in position observation of permanent magnet synchronous motors (PMSM). However, when observing the position of a permanent magnet synchronous motor using SMO, there are problems of chattering and slow observation speed. Therefore, in order to improve the anti-interference performance and control accuracy of the PMSM control system. Firstly, an integral nonsingular fast terminal sliding mode observer is studied to improve its observation speed. Secondly, in order to further reduce the chattering of the nonsingular fast terminal sliding mode observer, an adaptive sliding mode control law is designed, which is an adaptive nonsingular fast terminal sliding mode observer (ANFTSMO). An adaptive function related to the sliding surface is established before the switching function to adjust the amplitude of the switching function. Then, the closed-loop system is rigorously analyzed by using Lyapunov theory, and the stability of the observer is proved. Finally, the analysis and verification are carried out on the 1KW PMSM experimental platform, and the position feedback estimation of the studied observer is more accurate under the same torque. Therefore, PMSM has better control performance, stronger robustness and better system stability.