Reconstruction of extended speed observer for induction motor stability enhancement with stabilizing function

This study proposed an extended speed observer reconstruction for multiscalar control-based speed control of an induction motor (IM) traction drive for electric vehicles (EVs). It employs an extended-speed adaptive observer with a stabilizing function to enhance the sensorless control of IM low-speed operation. An approach for estimating rotor speed using machine models of multiscalar control with the stabilizing function is used for controlling IM drive for EVs. A stabilizing function is built using Lagrange's identity to meet the stability requirement and to reduce the unstable zone during a low-speed regenerating mode of operation. The pole-placement method selects the stabilizing function gains to minimize the estimation of rotor speed errors and to increase resilience against parameter uncertainties at zero and low rotor speed operation. The proposed speed estimator performance is compared to motor speed throughout several driving profiles of EVs, including motoring, constant speed, low speed, and regenerating modes of operation. The findings show that the proposed speed observer performs well across various driving profiles. The study found that using an adaptive full-order observer for speed sensorless control in EV is effective and stable.