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This work proposes a robust control scheme of a three-phase induction motor using a new Backstepping approach based on variable gains. Because of the saturation blocks that are essential to protect the control system, the use of conventional integral Backstepping could lead to a modest performance represented by overshooting and strong vibrations in transitional regimes that cause overcurrent. To develop an efficient and simple control algorithm, the variable gains propriety is used in the speed controller to offer a quick response without overshooting with good robustness against external disturbances. The same property has been introduced in current regulation by a different mean in order to develop a new solution to solve obstacles related to very low-speed operations. The asymptotic stability of the global control is proven by Lyapunov theory. The improvement of the new version compared with the classical one was verified by a brief comparative study based on simulation results. The proposed algorithm has been implemented in a dSPACE DS 1104 card, to analyze the real-time motor performance, and to test control sensitivity against parametric variations. The obtained results show a remarkable improvement of the new control concerning rapidity and stability of transient regimes, overtaking elimination and reduction of starting current, with a low algorithm sensitivity against parametric variations. We have also been able to confirm that the new current control method can guarantee optimal regulation in order to achieve a high-performance operation at very low-speed zones, in the presence of various internal and external disturbances.

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Induction Motors are the most used machines in the industrial field since the last century, due to their low cost, high robustness with satisfactory performance. However, they are still difficult to control compared to the DC motor because of the non-linearity presented in the mathematical model. Sliding mode theory is often used to develop powerful control against various internal and external disturbances. However, the chattering problem caused by the attractive part of the regulator is a serious problem for its applications. In this paper, the proposed solution for having an optimal performance consists in combining the Sliding Mode Control with an anti-windup proportional-integral regulator. This is achieved through a simple linear supervisor that can activate the sliding mode at start-up and transient regimes while making the second controller drive the steady state. The asymptotic stability of the delivered control signal is ensured via the Lyapunov method. This allows us to benefit from the advantages of the two regulators without having their disadvantages. This new hybrid technique can potentially offer very promising results in terms of robustness and control efficiency. The validation of this theory was carried out by simulation and then by practical implementation using a dSPACE-DS-1104 control board. The obtained results show a high-performance control with very good robustness against parametric variations and remarkable stability during all different operating zones.