A Luenberger State Observer for Simultaneous Estimation of Speed and Rotor Resistance in sensorless Indirect Stator Flux Orientation Control of Induction Motor Drive

The primary objective of this paper is to implement a sensorless indirect stator field oriented control (ISFOC) of induction motor drive with rotor resistance tuning. Indeed, the proposed method for simultaneous rotor speed and rotor resistance estimation is based on Luenberger observer (LO). In order to estimate the rotor speed and the rotor resistance, an adaptive algorithm based on Lyapunov stability theory by using measured and estimated stator currents and estimated stator flux is proposed. The suggested control scheme, as a result, achieves a sound performance with computational complexity reduction obtained by using the analytical relation to determine the LO gain matrix. Again, the observer is simple and robust, when compared with the previously developed observers, and suitable for online implementation. For current regulation, however, this paper suggests a conventional Proportional-Integral (PI) controller with feed-forward compensation terms in the synchronous frame. Owing to its advantages, an Integral-Proportional (IP) controller is used for rotor speed regulation. The design, analysis, and implementation for a 3-kW induction motor are completely carried out using a dSpace DS 1104 digital signal processor (DSP) based real-time data acquisition control (DAC) system, and MATLAB/Simulink environment. Digital simulation and experimental results are presented to show the improvement in performance of the proposed algorithm.