Extended Two-State Observer-Based Speed Control for PMSM With Uncertainties of Control Input Gain and Lumped Disturbance

In this article, an extended two-state observer (ETSO) is proposed for the permanent magnet synchronous motor (PMSM) with the uncertainties of system parameters and load torque. First, the ETSO is designed to estimate the two extended states, namely control input gain and lumped disturbance. The control input gain includes moment of inertia and stator flux linkage. Then, a speed controller with online adjustment for the control input gain is designed by using the estimates obtained from the ETSO to improve the speed tracking performance of PMSM. The convergence of the ETSO and the speed controller is analyzed by Lyapunov theory. Finally, simulations and experiments are carried out to verify the effectiveness of the proposed control scheme. The results demonstrate that the control input gain and the lumped disturbance are effectively estimated, and the speed tracking performance of the PMSM with the uncertainties of moment of inertia, stator flux linkage, and load torque is significantly improved.