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Navid Reza Abjadi

Bio: Navid Reza Abjadi is an academic researcher from Shahrekord University. The author has contributed to research in topics: Sliding mode control & Control theory. The author has an hindex of 11, co-authored 56 publications receiving 505 citations. Previous affiliations of Navid Reza Abjadi include Islamic Azad University & Isfahan University of Technology.


Papers
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Journal ArticleDOI
TL;DR: In this article, a sliding-mode feedback linearisation control system is designed for a multi-motor web-winding system, which consists of an SM velocity controller and two SM tension controllers; a decentralised version of the proposed controller is developed.
Abstract: A sliding-mode (SM) feedback linearisation control system is designed for a multi-motor web-winding system. First, an ideal feedback linearisation control system is adopted in order to decouple the tensions and velocity of the web-winding system; then to enhance the performance of the control system in the presence of uncertainties, an SM feedback linearisation control system is applied, which consists of an SM velocity controller and two SM tension controllers; a decentralised version of the proposed controller is developed. Two tension observers are suggested to eliminate the need of load cells in a web-winding system. Finally, the effectiveness and capability of the proposed control strategy is verified by computer simulation.

85 citations

Journal ArticleDOI
TL;DR: In this paper, an adaptive non-linear controller is designed for DC-DC buck/boost converter which is robust and stable against converter load changes, input voltage variations and parameter uncertainties.
Abstract: In this study, an adaptive non-linear controller is designed for DC-DC buck/boost converter which is robust and stable against converter load changes, input voltage variations and parameter uncertainties. The proposed controller is developed based on input-output linearisation using an adaptive backstepping approach. The controller can be applied in both continuous and discontinuous conduction modes (CCM and DCM). Owing to non-minimum phase nature of buck/boost converter, the output voltage of this converter is indirectly controlled by tracking the inductor reference current. The inductor reference current is generated by a conventional PI controller. Using a MATLAB/Simulink toolbox and a stand-alone TMS320F2810 digital signal processor from Texas Instruments, some simulations and practical results are presented to verify the capability and effectiveness of the proposed control approach.

66 citations

Journal ArticleDOI
TL;DR: In this paper, a proportional integral type hyperplane sliding mode controller has been designed for output voltage control of the DC-DC buck/boost converter for its continuous and discontinuous conduction modes of operating conditions.
Abstract: In this study, a new proportional–integral-type hyper-plane sliding mode controller has been designed for output voltage control of the DC–DC buck/boost converter for its continuous and discontinuous conduction modes of operating conditions. The proposed controller is robust and stable against parameters uncertainties, load disturbance and variations of the converter input voltage. In addition, it is capable of cancelling the non-minimum phase nature effect of the converter so that the designed controller does not need to know the inductor reference current. Moreover, the coefficients of the controller have been designed so that the steady-state error of the converter asymptotically converges to zero. The controller is designed based on fixed-frequency equivalent control approach. Using MATLAB/SIMULINK toolbox and digital signal processor (TMS320F2810) from Texas Instruments, some simulation and practical results are presented to verify the capability and effectiveness of the proposed control approach.

53 citations

Journal ArticleDOI
TL;DR: A direct torque and flux control is described for a six-phase asymmetrical speed and voltage sensorless induction machine (IM) drive, based on non-linear backstepping control approach, and the feasibility of the proposed control scheme is verified by simulation and experimental results.
Abstract: In this study, a direct torque and flux control is described for a six-phase asymmetrical speed and voltage sensorless induction machine (IM) drive, based on non-linear backstepping control approach. First, the decoupled torque and flux controllers are developed based on Lyapunov theory, using the machine two axis equations in the stationary reference frame. In this control scheme, the actual stator voltages are determined from dc-link voltage using the switching pattern of the space vector pulse-width modulation inverter. Then, for a given motor load torque and rotor speed, a so-called fast search method is used to maximise the motor efficiency. According to this method, the rotor reference flux is decreased in the small steps, until the average of real input power to the motor reaches to a minimum value. In addition, a model reference adaptive system-based observer is employed for online estimating of the rotor speed. Finally, the feasibility of the proposed control scheme is verified by simulation and experimental results.

37 citations

Journal ArticleDOI
TL;DR: In this paper, an adaptive nonlinear controller is designed for regulating the output voltage of DC-DC buck converters, which is stable and robust with subject to widely changes of load demands and input voltage variations.
Abstract: SUMMARY In this paper, an adaptive nonlinear controller is designed for regulating the output voltage of DC-DC buck converters, which is stable and robust with subject to widely changes of load demands and input voltage variations. The proposed controller is developed based on adaptive backstepping approach and can be applied for both Continuous and Discontinuous Conduction Modes (CCM and DCM). Using a stand-alone TMS320F2810 digital signal processor from Texas instruments, some simulations and experimental results have been obtained to verify the proposed control approach. These results are in good agreement and prove the effectiveness and capability of the controller for both CCM and DCM operations. Copyright © 2012 John Wiley & Sons, Ltd.

32 citations


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01 Sep 2010

2,148 citations

Journal Article
TL;DR: In this paper, two major figures in adaptive control provide a wealth of material for researchers, practitioners, and students to enhance their work through the information on many new theoretical developments, and can be used by mathematical control theory specialists to adapt their research to practical needs.
Abstract: This book, written by two major figures in adaptive control, provides a wealth of material for researchers, practitioners, and students. While some researchers in adaptive control may note the absence of a particular topic, the book‘s scope represents a high-gain instrument. It can be used by designers of control systems to enhance their work through the information on many new theoretical developments, and can be used by mathematical control theory specialists to adapt their research to practical needs. The book is strongly recommended to anyone interested in adaptive control.

1,814 citations

Journal ArticleDOI
TL;DR: The recent progress in two specific areas associated with multiphase systems are surveyed, namely power electronic supply control and innovative ways of using the additional degrees of freedom inMultiphase machines for various nontraditional purposes.
Abstract: Multiphase variable-speed drives and generation systems (systems with more than three phases) have become one of the mainstream research areas during the last decade. The main driving forces are the specific applications, predominantly related to the green agenda, such as electric and hybrid electric vehicles (EVs), locomotive traction, ship propulsion, “more-electric” aircraft, remote offshore wind farms for electric energy generation, and general high-power industrial applications. As a result, produced body of significant work is substantial, making it impossible to review all the major developments in a single paper. This paper therefore surveys the recent progress in two specific areas associated with multiphase systems, namely power electronic supply control and innovative ways of using the additional degrees of freedom in multiphase machines for various nontraditional purposes.

508 citations

Journal ArticleDOI
TL;DR: It is shown that the performance of the PWM techniques is very similar and that one CBPWM and one SVPWM technique are characterised with identical performance, however, using the algorithm complexity as the main criterion, space vector techniques are more involved.
Abstract: Multilevel inverter supplied multiphase variable-speed drive systems have in recent times started attracting more attention, due to various advantages that they offer when compared to the standard three-phase two-level drives. For proper functioning of such systems good pulsewidth modulation (PWM) strategy is of crucial importance. Control complexity of multiphase multilevel inverters increases rapidly with an increase in the number of phases and the number of levels. This paper deals with a three-level neutral point clamped (NPC) inverter supplied five-phase induction motor drive and analyses five PWM strategies: three are carrier-based (CBPWM) and two are space vector based (SVPWM). The aim is to provide a detailed comparison and thus conclude on pros and cons of each solution, providing a guideline for the selection of the most appropriate PWM technique. Experimental results are provided for all analysed PWM methods. The comparison of the PWM techniques is given in terms of the voltage and current waveforms and spectra, as well as the total harmonic distortion (THD) in a whole linear modulation index range, which is used as the global figure of merit. Properties of the common mode voltage (CMV) are also investigated. Complexity of the algorithms, in terms of the computational time requirements and memory consumption, is addressed as well. It is shown that the performance of the PWM techniques is very similar and that one CBPWM and one SVPWM technique are characterised with identical performance. However, using the algorithm complexity as the main criterion, space vector techniques are more involved.

136 citations

Journal ArticleDOI
TL;DR: A robust full-order adaptive stator flux observer is designed for a speed sensorless DTC-SVM system and a new speed-adaptive law is given.
Abstract: This paper describes a combination of direct torque control (DTC) and space vector modulation (SVM) for an adjustable speed sensorless induction motor (IM) drive. The motor drive is supplied by a two-level SVPWM inverter. The inverter reference voltage is obtained based on input-output feedback linearization control, using the IM model in the stator D-Q axes reference frame with stator current and flux vectors components as state variables. Moreover, a robust full-order adaptive stator flux observer is designed for a speed sensorless DTC-SVM system and a new speed-adaptive law is given. By designing the observer gain matrix based on state feedback H∞ control theory, the stability and robustness of the observer systems is ensured. Finally, the effectiveness and validity of the proposed control approach is verified by simulation results.

125 citations