Robust sensorless field oriented control of induction motor using sliding mode

This paper first presents systematic design of PI controllers for transient performance improvement of a field-oriented induction motor drive. Through extensive simulation, it is verified that P-I controller fails to give satisfactory response when load torque, stator resistance and rotor resistance change. Then, sliding mode speed and flux controller are designed to make the system robust to external disturbances, noise and unmodelled dynamics. Simulation results under load disturbances and parameter variations are obtained with the P-I controller and sliding mode controller. Results are compared to verify the robustness and superiority of sliding mode controller. The speed of the induction machine is also estimated to make the system sensorless.