Abstract: For the purpose of improving the speed regulation of permanent-magnet synchronous motor (PMSM) under disturbances and uncertainties, a nonlinear control algorithm based on nonsingular terminal sliding mode control method (NTSMC) was proposed. A speed tracking controller was presented by introducing a nonsingular terminal sliding mode manifold, which could not only solve the singularity problem but also make the manifold converge to zero in finite time. For the sake of reducing chattering phenomenon caused by discontinuous switching term, which usually contained sign function, a hyperbolic tangent function was utilized accounting for its continuity. Compared with the PI control method, the proposed scheme shows better robustness to torque disturbance as well as parameter variations. Numerical simulation verifies the tracking performance of proposed scheme. Simulation results show that the proposed scheme has better dynamic and steady performance in comparison with the classical PI method.

Key words: nonsingular terminal sliding manifold, hyperbolic tangent function, speed regulation, permanent magnet synchronous motor (PMSM)