Riad Toufouti - Academia.edu (original) (raw)

Papers by Riad Toufouti

Periodica polytechnica. Electrical engineering and computer science /, Jan 3, 2024

Stability in island microgrids is crucial for efficient power distribution among distributed gene... more Stability in island microgrids is crucial for efficient power distribution among distributed generation (DG) inverters. Conventional droop control, while effective in power sharing, poses challenges with voltage stability due to frequency and voltage deviations resulting from changing load power. Such deviations can lead to system instability, impacting power flows within each inverter. Therefore, this paper introduces a proposed droop control approach that effectively tackles the issues of frequency and voltage deviation, aiming to restore them to their rated values and significantly enhance transient response in power flows among inverters. The novel method incorporates integrating controllers for frequency and voltage, coupled with the utilization of virtual impedances. These virtual impedances, comprising virtual positive/negative-sequence impedance (VPI/VNI) loops at the fundamental frequency and a virtual harmonic impedance (VHI) loop at harmonic frequencies, play a crucial role in overcoming mismatched line impedance conditions, ultimately improving overall system performance. Simulation results demonstrate the effectiveness and outstanding performance of inverters operating in parallel within an island AC microgrid. The proposed approach ensures stable voltage and frequency levels in all operational states, regardless of varying load conditions.

Advances in systems analysis, software engineering, and high performance computing book series, 2021

The integration in the isolated areas and rural sectors is a better solution for producing the el... more The integration in the isolated areas and rural sectors is a better solution for producing the electrical energy needed for applications such as pumping systems. The rural water demand for crop irrigation and domestic water supplies is increasing. For this, one of the most conceived solutions is the photovoltaic water pumping technology which has the advantage of being sustainable and respectful of the environment to supply water to rural areas. This chapter describes a robust control of a standalone photovoltaic water pumping system using induction motor drive coupled with a centrifugal hydraulic pump. The induction motor is controlled by algorithm called an adaptive nonlinear control uses a combination of the adaptive observer for rotor flux and nonlinear control technique. The variables to be controlled are the rotor speed and the rotor flux norm required to implement the nonlinear control algorithm is estimated by adaptive flux observer. Simulations are carried out in order to show the effectiveness of the drive and the robustness to parameters variations.

International Journal of System Dynamics Applications, 2018

This article describes how a field oriented control can provide the same performance as it is ach... more This article describes how a field oriented control can provide the same performance as it is achieved by a DC motor. However, this technique requires a mechanic sensor and is very sensitive to the variation of motor parameters which results in an undesirable coupling between the flux and the torque. To solve these problems, this paper proposes a global stability and robust nonlinear controller, applied to induction motor (IM), in order to achieve an exact decoupling between speed and flux for all motor operating conditions. The induction motor is coupled with a centrifugal hydraulic pump, powered by a photovoltaic array speeding system. The proposed system is designed for usage in rural areas or remote electricity needs in absence of the grid network. A nonlinear controller adjusts the motor speed reference to attain the maximum power point (MPPT). In presence of rotor and stator resistances and irradiation disturbance the results obtained by simulations confirm the effectiveness o...

International Journal of Control, Automation and Systems, 2010

In this paper, a novel direct torque neuro-fuzzy control (DTCNF) scheme combining with space volt... more In this paper, a novel direct torque neuro-fuzzy control (DTCNF) scheme combining with space voltage modulation (SVM) technique of a three levels inverter is presented. Using neuro-fuzzy technique, the reference space voltage vector can be obtained dynamically in terms of torque error, stator flux error and the angle of stator flux. Compared with conventional direct torque control (C_DTC), in this new technique, the ripples of both torque and flux are reduced remarkable, and switching frequency is maintained constant. Simulation results verify the validity of the proposed method.

Studies in Computational Intelligence, 2014

The induction motor squirrel cage that is deemed by its strength, high torque mass, and its relat... more The induction motor squirrel cage that is deemed by its strength, high torque mass, and its relatively low cost ... etc, meanwhile, it benefited from the support of industry since its invention. Despite these advantages, the induction motor has complex dynamic systems that exhibit a strong nonlinearity, which makes them difficult to be controlled. The use of control algorithms is therefore desirable that both stabilization trajectory tracking. This paper seeks to analyze dynamical performances and sensitivity to motor parameter changes of two techniques of induction motor, Sliding Mode Control and Field Oriented Control. Comparison between the two techniques is made through computer simulations.

Springer eBooks, 2021

To solve the problem of water for irrigation in isolated regions and rural remote areas, where th... more To solve the problem of water for irrigation in isolated regions and rural remote areas, where the expansion of the power network line is complex and she is more costly. In this paper a control of the wind pumping systems is presented. Classical control strategy of induction motors (IMs) is very sensitive to the variation of rotor resistance, to leads a strong coupling between the rotor flux and the electromagnetic torque. To resolve this difficulty, we propose in this paper, a nonlinear control of high performance applied of induction motor, to improve the tracking control, for guarantee stability, robustness to parameter variations, perfect decoupling between the flux and torque. The robustness of the proposed study is confirmed through software simulation with parameter variations. Keywords Wind energy • Induction motor • PMSG • Input output linearization • Centrifugal hydraulic pump • Water pumping system 1 Introduction Water supply, livestock and domestic necessities are main issues in the progress of isolated and Saharan regions, where the extension of the conventional power network remains very hard to do [1, 2]. Therefore, recently it is necessary to use inexhaustible resources to fulfill their energy requirements. [2, 3]. The demand for rural water for domestic supplies and irrigation is increasing, with the result that surface water become increasingly scarce in the future [4, 8]. For this, it seems that the only and good alternative to this problem is groundwater. but the water table also decreases, making manual pumping more challenging. However, the pumping of water mechanized will be the only dependable substitute for lifting water

Renewable Energy and Sustainable Development, 2015

2016 4th International Conference on Control Engineering & Information Technology (CEIT), 2016

The field oriented control (FOC) can provide the same performance as is achieved from a separatel... more The field oriented control (FOC) can provide the same performance as is achieved from a separately excited DC motor. However, this technique requires the mechanic sensor to determine correctly the orientation of the rotor flux vector and is very sensitive to the variation of motor parameters, results in an undesirable coupling between the flux and the torque of the machine, and loss of dynamic performance. To solve these problems, this paper proposes a global stability and robust nonlinear controller applied to the ideal induction motor speeding system, and dynamic decoupling of rotor speed and flux. A comparative study between the performances of the proposed controller and field oriented control is carried out. In presence of rotor resistance variations and load torque disturbance the simulation results show the proposed control method behaves preferable dynamic decoupling performance and robust performance.

Digital Technologies and Applications, 2021

Recently the generations by the traditional sources are insufficient to meet the increasing power... more Recently the generations by the traditional sources are insufficient to meet the increasing power demands due to continuous depletion of fossil energy sources, therefore distributed generators (DGs) based renewable energy sources (RES) to system is necessary to overcome these issues. In this study we present a stand-alone hybrid power generation system composed by a photovoltaic and wind power generation sources with energy system storage to achieve high performance while supplying unbalance AC load, PV system and Win turbine is operated with a DC/DC boost converter to extract the Maximum Power Point Tracking (MPPT) using the fuzzy logic technique. The total power generation supply the load via an inverter controlled by pulse width modulation technique. A Simulink model of the proposed hybrid system with the MPPT controlled Boost converter of the PV generator and Voltage regulated voltage source inverter for standalone system is simulated in MATLAB.

Journal of Electrical Engineering-elektrotechnicky Casopis, 2017

In Steel Industry a DC electric arc furnace (DC EAF) is an important nonlinear time-varying load ... more In Steel Industry a DC electric arc furnace (DC EAF) is an important nonlinear time-varying load in power system. The operation of DC EAF causes many power quality problems especially they generate currents harmonics. In this paper we present a model of DC Electric Arc Furnace based on the stochastic nature of the electric arc current-voltage characteristic. For the study of harmonics generated in this steel industry with different structures proposed basing on utilization of twelve power rectifiers. The model has been implemented using a numerical simulation environment to facilitate later analysis. Finally, the simulation results are compared with different structures of a DC EAF, when the total Harmonic Distortion (THD) is determined and spectral representation to compares between each structure. Keywords_ Electrical arc, DC EAF, Modelling, Harmonics, Power Quality, Simulation

Journal of Control Engineering and Applied Informatics, 2009

In this paper, a novel direct torque neuro-fuzzy control (DTCNF) based space voltage modulation (... more In this paper, a novel direct torque neuro-fuzzy control (DTCNF) based space voltage modulation (SVM) technique for dual two level inverter fed induction motor is presented. The proposed scheme produces voltage space vector locations identical to those of a conventional three-level inverter. In this new scheme an adaptive NF inference system (ANFIS) to replace the switching table and the hysteresis comparators, for generate the reference voltage using space vector modulation (SVM) techniques for dual two level inverter. Compared with conventional direct torque control (C_DTC), in this new technique, the ripples of both torque and flux are reduced remarkable, and switching frequency is maintained constant. Simulation results verify the validity of the proposed method.

World Academy of Science, Engineering and Technology, International Journal of Computer and Information Engineering, 2014

International Journal of Computer Applications, 2014

In this paper, we'd like to present a tool for modeling and representing systems that allows a su... more In this paper, we'd like to present a tool for modeling and representing systems that allows a subsequent structuring of their control o. This tool, which is the causal informational graph (CIG), allows to highlight the different relationships between energy variables in a system; supplemented by another tool that is the macroscopic energy representation (MER), which insists on the principle of action and reaction between the different elements of the system. These tools enable a dual interest, first developing the model for the system structure and its control. In this article we consider the application as electromechanical conversion chain with actuator as an induction machine.

Direct Torque Control of inverter-fed Induction Machine allows high dynamic performance by means ... more Direct Torque Control of inverter-fed Induction Machine allows high dynamic performance by means of very simple control schemes. In this paper various direct torque control methodologies as conventional DTC (C_DTC), modified DTC (M_DTC) and twelve sectors (12_DTC) have been analysed and compared in order to evaluate the influence of the motor operating condition on steady state performances. A particular emphasis on stator flux trajectory, torque ripple and stator current distortion has been made. Simulation results show the effectiveness of the proposed methods.

International Journal of Computer Applications, 2012

This paper present a new advanced control algorithm based on continuous minimization of predicted... more This paper present a new advanced control algorithm based on continuous minimization of predicted tracking errors, to achieve torque, rotor speed and rotor flux amplitude tracking objectives. This algorithm called a new Adaptive Nonlinear Predictive Control to induction motor drive uses a combination of the adaptive observer for rotor flux and Cascaded Nonlinear Predictive Control technique. The variables to be controlled are the rotor speed and the rotor flux norm, required to implement the predictive control algorithm is estimated by flux observer. The parameters identified adaptively are stator and rotor resistance which vary with motor temperature using the adaptive rotor flux observer. A stability of the proposed adaptive flux observer will be proved by the Lyapunov's theorem. Simulations are carried out in order to show the effectiveness of the drive and the robustness to parameters variations.

Acta Electrotechnica et …, 2008

The basic concept of direct torque control of induction machines is investigated in order to emph... more The basic concept of direct torque control of induction machines is investigated in order to emphasize the effects produced by a given voltage vector on stator flux and torque variations. The low number of voltage vectors which can be applied to the machine using the basic DTC scheme may cause undesired torque and current ripple. An improvement DTC schemes proposed in the research literature is presented and compared with the classical. In this paper, we propose two approach's of improvement of Direct Torque Control (DTC) of Induction motor, first is Discrete Space Vector Modulation (DSVM_DTC) Where the Stator flux and torque are controlled using respectively by five-level hysteresis comparators, second is and The discrete time direct torque control (DTDTC) requires voltage and current measurements to calculate the back-EMF, and address the problem with torque ripple in the basic DTC system is introduced. Numerical simulations tests have been carried out to validate the proposed method.

Acta Polytechnica Hungarica, 2008

This paper, we propose the comparative study between the performances of the proposed controller ... more This paper, we propose the comparative study between the performances of the proposed controller and field oriented control. With an aim of improving the field oriented control, the control of the induction motor by Input-Output linearization techniques are used to track torque and rotor flux and the scheme is extended for speed control is presented. The methods are compared in terms of their ability to handle loads on the motor shaft, their speed tracking capability and their sensitivity to operating condition variations. To estimate the rotor flux, an open loop observer the Extended Kalman Filter (EKF) algorithm is used. A reduced dynamic motor model is used which reduces the computational requirements of the EKF. Simulation results show the effectiveness of the proposed method.

IEEE Transactions on …, 2001

Journal Européen des Systèmes Automatisés

This paper presents a hierarchical wireless control scheme for parallel distributed generation (D... more This paper presents a hierarchical wireless control scheme for parallel distributed generation (DG) units in islanded AC microgrids. The proposed control scheme is divided into primary and secondary control layers. The primary control layer includes an improved finite set-model predictive control (FS-MPC) with a dualobjective cost function based on the proposed droop approach. The benefit of the proposed droop approach is the ability to generate the reference voltage without any amplitude deviation, unlike the conventional droop technique, which may cause deviations. Furthermore, double virtual impedances are proposed, with the first one being used to reduce the effects of feeders' mismatched impedance, while the second one is used to increase the output impedance resistance, leading to enhanced accuracy of active and reactive power sharing among DG units. The secondary control layer helps to establish global controllability by keeping the frequency and amplitude voltage of the AC bus at their nominal values. The simulation results show that the proposed control is capable of ensuring appropriate power sharing among parallel DG units and achieving voltage quality at the AC bus under different load conditions.

Electrical Engineering, 2016

A squirrel cage induction motor has been the workhorse in industry for variable speed application... more A squirrel cage induction motor has been the workhorse in industry for variable speed applications in a wide power range that covers from fractional horsepower to multi megawatts. But the control and estimation of ac drives in general are considerably more complex than those of dc drives. The advent of vector control techniques has partially solved induction motor control problems. However, these techniques are very sensitive to the variation of motor parameters, result in an undesirable coupling between the flux and the torque of the machine, and loss of dynamic performance. To solve these problems this paper presents a synthesis of two control strategies, for controlling speed and rotor flux of induction motor (IM) via nonlinear control (NLC) and sliding mode control (SMC). Computer simulations are carried out to show the robustness of the proposed method against rotor resistance and load torque variations. The performance of SMC has been successfully compared with nonlinear control.