Research Article DSP-based adaptive backstepping using the tracking errors for high-performance sensorless speed control of induction motor drive Abderrahmen Zaafouri, Chiheb Ben Regaya n , Hechmi Ben Azza, Abdelkader Châari Unit C3S, Higher National Engineering School of Tunis (ENSIT), University of Tunis, 5 Av. Taha Hussein, 5 BP 56,1008 Tunis, Tunisia article info Article history: Received 9 January 2015 Received in revised form 28 September 2015 Accepted 19 November 2015 Available online 3 December 2015 This paper was recommended for publica- tion by Dr. Prof. A.B. Rad. Keywords: Induction motor (IM) Backstepping Adaptive observer Sensorless control Vector control PI control Digital signal processor (DSP) Space vector Pulse width modulation (SVPWM) dSpace DS1104 abstract This paper presents a modified structure of the backstepping nonlinear control of the induction motor (IM) fitted with an adaptive backstepping speed observer. The control design is based on the back- stepping technique complemented by the introduction of integral tracking errors action to improve its robustness. Unlike other research performed on backstepping control with integral action, the control law developed in this paper does not propose the increase of the number of system state so as not increase the complexity of differential equations resolution. The digital simulation and experimental results show the effectiveness of the proposed control compared to the conventional PI control. The results analysis shows the characteristic robustness of the adaptive control to disturbances of the load, the speed variation and low speed. & 2015 ISA. Published by Elsevier Ltd. All rights reserved. 1. Introduction The induction motor has many advantages over other types of electric motors as their high efficiency, high speed and lifetime. These advantages and technological advances in power electronics fields and signal processing have allowed the induction motor to work in the most difficult environments and have a low main- tenance cost [1,2]. In variable speed applications that require accurate dynamic despite different types of disturbances and parametric uncertain- ties, conventional linear controllers as PI and PID are difficult to adjust with a nonlinear problem. In this case, performance can be improved by nonlinear control techniques. Recent years have seen rapid progress in the control of nonlinear systems. In particular several accurate linearization techniques have been applied to the control of asynchronous machines. These techniques require the knowledge of system parameters, which is not generally the case for electric machines [3,4]. To improve the robustness of the control towards the parametric variations, especially the rotor resistance, many researches have proposed the nonlinear control laws and nonlinear speed observer. Among them, the sliding mode control and the backstepping control. The sliding mode technique was applied to the induction machine, but the main drawback of this type of control is gains adjustment even if the maximum value can be formulated from the upper bounds of uncertainties [5], and appearance of the chattering phenomenon [6,7]. Other researches use the backstepping method for the control design and rotor speed estimation. Backstepping method has recently appeared allowing the design of the control law and also the estimation of motor para- meters [8,9]. In [10], the authors present a new control scheme using a novel dynamical model of the induction motor based on the classical backstepping control with the unknown of the motor inertia, the damping coefficient, the load torque and the uncer- tainty of the rotor resistance without applying a load torque in the tests carried out. However, the comparative study presented in [11] shows that this type of control present a high bandwidth for the speed signal which is not close to the reference speed, and does not guarantee a total rejection of the disturbance (load Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/isatrans ISA Transactions http://dx.doi.org/10.1016/j.isatra.2015.11.021 0019-0578/& 2015 ISA. Published by Elsevier Ltd. All rights reserved. n Corresponding author. E-mail address: chiheb_ben_regaya@yahoo.fr (C.B. Regaya). ISA Transactions 60 (2016) 333–347