Improved Sensorless Vector Control of Induction motor Using Sliding Mode Observer

This work deals with a sensorless speed control for three-phase induction motor in order to improve its operation at low speed. Initially, a direct field oriented control employing space vector pulse with modulation based on sliding mode observer (SMO) is studied and evaluated due to its high accuracy in estimating the flux at low speed. The proposed current model based on SMO provides good speed estimation under low speed and parameter or load changes. Simulations and experimental tests with diferent operational conditions at low speed are carried out in order to test the sensorless control. The results show a good perfomance and agreed with the results shown in recent papers.