Robust Sliding Mode Observer Based Speed Sensorless Control of FPIM for Wide Range of Speed Operation

In sensorless speed control, the conventional speed estimation techniques often encounter challenges such as chattering and convergence issues, especially at low speeds, leading to potential performance degradation or instability. In contrast, sliding mode observers can significantly enhances the system reliability under harsh operating conditions. The present paper introduces a Continuous Fast Terminal Sliding Mode Observer (CFT-SMO) based speed estimation technique for five-phase induction motor (FPIM) drive. An adaptive gain mechanism is included to offer rapid convergence and robust speed tracking across a broad operating speed range, ensuring stability and precise tracking even at very low speeds. The proposed CFT-SMO is incorporated with Indirect Field Oriented Control (IFOC) scheme to leverage the observer's capabilities to the fullest under extreme system dynamics. The stability of the observer is rigorously validated through Lyapunov stability theory. The performance of the combination of IFOC with the proposed observer is evaluated in MATLAB/SIMULINK. It ensures optimal performance and reliability of the control system under varying operating conditions. A hardware prototype is developed in laboratory and typical hardware result is presented.