Energy optimized sensorless sliding mode control of IM drive taking core losses into account

This paper presents a novel sensorless discrete sliding-mode (SM) stator flux and torque controller for three-phase Induction motor drive which is supplied by a three level SVM voltage source inverter (VSI). The stator flux is estimated by a sliding-mode observer and is employed in the rotor speed and stator resistance estimation. In the proposed method the motor iron losses is modeled by a rotor speed dependent shunt resistance in IM two axis equivalent circuits. The system efficiency is optimized by adjusting the magnitude of stator flux reference value for a given motor load and motor speed. To do so, two different methods named as Model Based Approach (MBA) and On-line Search Approach (OSA) are adopted. Finally, some simulation results are presented to show the capability and validity of the proposed control scheme.