## Liste des publications

#### Novel and simplified model representing Current-Output Phase-Shift Full-Bridge DC-DC LCLC Resonant Converter in Arc Welding Application

In this paper, a novel and simplified model representing current-output phase-shift full-bridge DC-DC LCLC resonant converter in arc welding application is thoroughly presented. First, a switched model written in state space representation and featuring a bilinear form is proposed. The latter facilitates the derivation of both the reduced and full order averaged models in continuous conduction mode (ROAM and FOAM). Although the FOAM can be employed in linear or nonlinear control schemes and the derivation of steady state behavior, in this paper the ROAM is considered in designing both voltage mode control and current mode control by using the classical PID and the fractional order PID controllers. Simulation confirms that the switched model, ROAM and FOAM are quite accurate compared to the circuit simulation using SimPowerSystem toolbox of MATLAB/SIMULINK. Results clearly showed that depending on the switching frequency, the proposed topology can be applied either in constant voltage characteristic or dropped characteristic welding machines fulfilling either zero current Switching (ZCS) or zero voltage switching (ZVS). Besides, the fractional order PID controller seems to be more adapted for arc welding application than its traditional version. Voir les détails

**Mots clés : **LCLC resonant converter, switched model, reduced order averaged model, full order averaged model, arc welding, FOPID, IGWO

#### State Feedback Control of DC-DC Converter Using LQR Integral Controller and Kalman Filter Observer

In this paper, the linear state feedback control using LQR controller for a DC/DC converter in the case of negative voltages topology is presented in order to achieve a particular desired behavior. To guarantee a zero steady-state error, we introduce an integral action, which will work out this problem by assuring that the steady-state error will end up to zero. For filtering and state estimation with a low cost and less complexity a state observer is obtained based a Kalman Filter observer. Detailed simulation study is presented to demonstrating the robustness and effectiveness of the proposed control scheme. Voir les détails

**Mots clés : **Linear quadratic regulator, DC/DC Buck-Boost Converter, Kalman filter, Static error

#### New Optimal Control of Permanent Magnet DC Motor for Photovoltaic Wire FeederSystems

This article aims to improve the permanent magnet DC (PMDC) motor performance forphotovoltaic (PV) wire-feeder systems (PVWFSs) of arc welding machines. Theconsidered technique is designed by direct speed control based on optimal Fractional-orderFuzzy PID FO-Fuzzy-PID controller. The purpose is to ensure optimal control of wire feedspeed reference to reduce torque ripples and hence, the performance of the WFS isimproved. The dynamic reaction of the proposed solar PVWFS relies upon the scalingfactors of FO-Fuzzy-PID controller, which are optimized by using teaching-learningalgorithm based on Particle Swarm Optimization (PSO) method. The maximum powerpoint tracking (MPPT) is achieved using an intelligent FO-Fuzzy-PID current controllerbased Perturb and Observe (P&O) MPPT algorithm. The PVWFS system incorporatingthe proposed method is tested and compared with the conventional PID control schemeunder different weather conditions. The simulation of the proposed system byMATLAB\SIMULINK is carried out. The simulation results indicate the effectiveness ofthe considered control strategy in terms of the reduction in torque oscillations, optimizingelectrical power and wire feed speed. Voir les détails

**Mots clés : **Solar photovoltaic (PV) module, wire feeder systems (WFSs), DC-DC buck converter, MPPT control, FO-Fuzzy PID controller, Particle Swarm Optimization (PSO) algorithm

#### Sensorless Control of DC-DC Converter Using Integral State Feedback Controller and Luenberger Observer

This paper presents a design of linear state feedback control of DC-DC Boost converters, in order to achieve a particular desired behavior. To guarantee a zero steady state error, we introduce an integral action, which will work out this problem by assuring that the steady state error will end up to zero. If it is supposed that both the voltage and current are measured, so much more sensors are needed then and consequently causing a high cost, so that to estimate the voltage and current with a low cost and less complexity it is preferred to introduce a state observer. An observer or estimator is a dynamic system that uses the available information on a real system, according to the inputs and outputs of the real process and estimate the system state. Simulations results demonstrate the robustness and effectiveness of the proposed control scheme. Voir les détails

**Mots clés : **Boost converter, observer, Static error, Feedback control

#### An Enhanced MPPT Method CombiningFractional-Order and Fuzzy Logic PIDController for a Photovoltaic-Wire FeederSystem (PV-WFS)

The use of photovoltaic (PV) module as a power source for wirefeeder systems (WFSs) of arc welding machines is one of the promisingdomains in the solar PV applications. This paper provides a new kind of weldingWFS and investigates the PV penetrated power systems. The considered systemconsists of a PV module, a DC-DC buck converter, and PMDC motor. Thepower of the PV-WFS can be widely enhanced by using a Fractional-orderFuzzy PID (FO-Fuzzy-PID) controller based P&O MPPT algorithm. In thiswork, a FO-Fuzzy-PID controller is also proposed for PMDC motor drivenWFS. This will lead consequently to optimize the mechanical motor speed of theWFS. The dynamic response of the PV-WFS relies upon the parameters of theseFO-Fuzzy-PID controllers, which are optimized by using Particle SwarmOptimization (PSO) algorithm. Simulation results found are satisfactory andprove the stability, accuracy and dynamic response of the synthesized optimizedwire feeder regulating system and the proposed intelligent MPPT algorithm. Voir les détails

**Mots clés : **Solar photovoltaic (PV) module, Wire feeder system (WFS), Arc welding machines, DC-DC buck converter, MPPT control, FO-Fuzzy PID controller, Particle Swarm Optimization (PSO) algorithm

#### New Optimal Control of Permanent Magnet DC Motor for Photovoltaic Wire Feeder Systems

This article aims to improve the permanent magnet DC (PMDC) motor performance for photovoltaic (PV) wire-feeder systems (PVWFSs) of arc welding machines. The considered technique is designed by direct speed control based on optimal Fractional-order Fuzzy PID FO-Fuzzy-PID controller. The purpose is to ensure optimal control of wire feed speed reference to reduce torque ripples and hence, the performance of the WFS is improved. The dynamic reaction of the proposed solar PVWFS relies upon the scaling factors of FO-Fuzzy-PID controller, which are optimized by using teaching-learning algorithm based on Particle Swarm Optimization (PSO) method. The maximum power point tracking (MPPT) is achieved using an intelligent FO-Fuzzy-PID current controller based Perturb and Observe (P&O) MPPT algorithm. The PVWFS system incorporating the proposed method is tested and compared with the conventional PID control scheme under different weather conditions. The simulation of the proposed system by MATLAB\SIMULINK is carried out. The simulation results indicate the effectiveness of the considered control strategy in terms of the reduction in torque oscillations, optimizing electrical power and wire feed speed. Voir les détails

**Mots clés : **Solar photovoltaic (PV) module, wire feeder systems (WFSs), DC-DC buck converter, MPPT control, FO-Fuzzy PID controller, Particle Swarm Optimization (PSO) algorithm

#### Auto-control technique using gradient method based on radial basis function neural networks to control of an activated sludge process of wastewater treatment

Dissolved oxygen (DO) concentration is a key variable in the activated sludge wastewater treatment processes. In this paper, an auto control strategy based on Euler method and gradient method with radial basis function (RBF) neural networks (NNs) is proposed to solve the DO concentration control problem in an activated sludge process of wastewater treatment. The control purpose is to maintain the dissolved oxygen concentration in the aerated tank for having the substrate concentration within the standard limits established by legislation of wastewater treatment. For that reason, a new proposed control strategy based on gradient descent method and RBF neural network has been used. Compared with RBF neural network PI control, the obtained results show the effectiveness in terms of both transient and steady performances of proposed control method for dissolved oxygen control in the activated sludge wastewater treatment processes. Voir les détails

**Mots clés : **activated sludge process, Wastewater treatment, Gradient descent algorithm, RBF neural network, PI control

#### Predictive Control of a Grid Connected PV System Incorporating Active power Filter functionalities

This article proposes a multifunction of a double stage grid connected photovoltaic (PV) system, with insertion the active power filter (APF) functionalities. This system is used to compensate the harmonics currents, compensate reactive power, supply the nonlinear loads and inject the PV system's active power into grid. This study is based on grid side, a perturb and observe algorithm is used to extract the maximum power point tracking (MPPT) from the PV array regardless of solar irradiance. On the grid side, a modified instantaneous active and reactive power theory (P-Q) based on a multi-variable filter (MVF) is applied to correctly identify the harmonics currents reference under distorted source voltage condition, also a modified predictive current control (PCC) algorithm is used to generate the switching signals for the source voltage inverter in order to ensure compensate reactive power and harmonic currents, feed the non linear load and inject the surplus of active powerinto the grid. In Matlab/Simulink™ software environment, the performance of the proposed control scheme is investigated under load change and irradiance change conditions. Simulations results demonstrate that the proposed PCC of the APF ensure a manage of active power exchanges with the grid with power factor correction. Furthermore, the grid current recovers its sinusoidal waveform with a total harmonic distortion (THD) meet to IEEE-519 standard. Voir les détails

**Mots clés : **Photovoltaic system (PV), activ power filter (APF), Predictive current control (PCC), active and reactive power theory (P-Q), multivariable filter (MVF), total harmonic distortion (THD)

#### A Comparison Study: Direct and Indirect ModeControl of Perturb and Observe-MPPT Algorithmsfor Photovoltaic System

The Perturb and Observe P&O algorithm hasbeen widely used in most real-world applications due to itssimplicity of implementation in the control loops. Its main idea isto adjust the operating point of photovoltaic PV panels to ensurea good tracking behavior of a desired Maximum Power PointMPP. The P&O algorithm is one of the most used MPPTalgorithms to extract the electrical energy of PV panels underdifferent weather conditions. This can be done via the directcontrol mode of the DC-DC boost converter which commonlylinked by an external resistive load. However, the given electricalpower of the P&O-MPPT algorithm becomes fluctuating in thesmall time range, especially when the current MPP is graduallyapproaching the desired one. It provides unfortunately a steadystatepower oscillation problem and a loss of electrical energy at asudden change of climatic conditions. The indirect control modeof the DC-DC boost converter via P&O-MPPT algorithm isadopted as an alternative key to avoid the above mentioneddrawbacks where electrical performances are well enhanced interm of transient and steady-states of the given output powerresponse, the MPP tracking accuracy, the given electrical energyratio and so on. This goal can be reached through the followingsteps. The desired reference voltage perturbation is firstlycomputed by the standard P&O algorithm using the MPPmeasurements recorded through the actual PV panel at thestandard test condition STC (i.e., nominal absolute temperatureand nominal solar irradiance). It then compared by the actualvoltage perturbation generated by the closed loop P&O-MPPTscheme, providing thus the discrepancy voltage perturbation.Finally, a Proportional-Integral-Derivative PID controller givenin the P&O-MPPT inner loop scheme is used to mitigate as muchas possible the previous voltage error perturbation. This yields adesired duty cycle perturbation of the DC-DC boost converterwhich allowing reaching a good trade-off between both transientstatespeed and steady-state stationary of the output powerresponse. Simulation results confirm the effectiveness of theindirect control mode of the P&O –MPPT algorithm over thedirect control mode of same algorithm for several suddenchanges in weather conditions and wide variations of the resistiveload. Voir les détails

**Mots clés : **PV system, Boost converter, P&O algorithm, Direct and indirect control modes

#### Fuzzy controller design using particle swarm optimization for photovoltaic maximum power point tracking

Recently, researchers have strongly promoted the use of solar energy as a viable source of energy due to its advantages and which it can be integrated into local and regional power supplies. The P-V curve of photovoltaic system exhibits multiple peaks under various conditions of functioning and changes in meteorological conditions which reduce the effectiveness of conventional maximum power point tracking (MPPT) methods and the Particle Swarm Optimization (PSO) algorithm is considered to be highly efficient for the solution of complicated problems. In this paper, the application of this approach based MPPT algorithm for Photovoltaic power generation system operating under variable conditions is proposed to optimize and to design an intelligent controller comparing to conventional one. Voir les détails

**Mots clés : **PV systems, Boost, PWM, MPPT, FLC, PSO