Advanced Sensorless Direct Field-Oriented Control for a Five-Phase Induction Motor Based on an Extended Robust Third-Order Super-Twisting Sliding Mode Controller and a New Model Reference Adaptive System

Abstract

This paper presents a novel robust sensorless control strategy for Five-Phase Induction Motor (FPIM) drives based on an enhanced Direct Field-Oriented Control (DFOC) framework. The proposed approach integrates an extended Third-Order Super-Twisting Sliding Mode Speed Controller (TOSTSMSC) with a hybrid Model Reference Adaptive System–Adaptive Sliding Mode Observer (MRAS–ASMO) for robust speed estimation. Unlike existing FPIM control schemes that predominantly employ PI, first-order, or second-order super-twisting controllers, the proposed TOSTSMSC introduces a higher-order sliding structure that ensures the finite-time convergence of the speed error while significantly attenuating the chattering effects. In addition, conventional MRAS-based observers used in FPIM drives are highly sensitive to rotor resistance variations and parameter uncertainties. To overcome this limitation, a hybrid MRAS–ASMO scheme is employed for sensorless speed estimation, where the ASMO provides online rotor resistance adaptation, thereby enhancing the robustness under thermal effects and model mismatches. Finally, the comprehensive simulation results demonstrate the superior dynamic performance, robustness, and reliability of the proposed DFOC–TOSTSMSC–MRAS–ASMO control strategy compared with conventional approaches, confirming its effectiveness for high-performance FPIM drives.