Position sensorless vector control of PMSM drives based on SMO

In this document, an sensorless field oriented control (FOC) for PMSM utilizing the SMO is proposed. We have building a new sliding mode observer to estimate the rotor velocity/position from the back EMF, in which a continuous function (called sigmoid) is applied instead the sign method. The stability verification of our observer was made by the Lyapunov theorem. The effectiveness of sensorless FOC was validated by the results obtained in section 4. The simulation results obtained by using Matlab/Simulink program validate the robustness of the SMO under parameter variations and external disturbance.