Discrete Terminal Super-Twisting Current Control of a Six-Phase Induction Motor

• Published in: Energies (Basel) Vol. 14; no. 5; p. 1339
• Main Authors: Kali, Yassine, Saad, Maarouf, Doval-Gandoy, Jesus, Rodas, Jorge
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.03.2021
• Subjects: Algorithms; Closed loop systems; discrete-time current control; field oriented control; Lyapunov; multiphase induction motor; super-twisting control; terminal sliding mode
• ISSN: 1996-1073; 1996-1073
• DOI: 10.3390/en14051339

In this manuscript, the high-accuracy stator currents tracking issue is considered for a six-phase induction motor subject to external perturbations and uncertainties due to unmeasurable rotor currents and electrical parameter variations. To achieve the control goals, the common two-cascade controllers structure is required for this type of motor. The first controller in the outer loop consists of a proportional integral to regulate the speed. Then, the second is the proposed inner nonlinear stator currents controller based on a robust discrete-time terminal super-twisting algorithm supported by the time-delay estimation method. For the design procedure, the discrete-time stator currents dynamics are derived; for example, the vector of the matched perturbations and unmeasurable rotor currents are specified to simplify the estimation. A detailed stability analysis of the closed-loop error dynamics using Lyapunov theory is given. Finally, a real asymmetrical six-phase induction motor is used to implement in real-time the developed method and to illustrate its effectiveness and robustness. The results obtained reveal a satisfactory stator currents tracking in steady state and transient conditions and under variation in the magnetizing inductance. Moreover, a comparative study with an existing method in steady state for two different rotor speeds is presented to show the superiority of the proposed discrete-time technique.