Electrotechnique
Fuzzy monitoring of stator and rotor winding faultsfor DFIG used in wind energy conversion system
According to its high robustness, the use of doubly-fed induction generators in thewind energy conversion takes an important place in the world of production of electrical energy.This type of conversion became very attractive because of its manufacturing environments,low cost and operation with an easily available power supply. The increase interest in windenergy conversion has been accompanied by efforts to improve reliability, effective conditionmonitoring and better efficiency. In this work, a new technique is proposed for monitoring anddetection of inter-turn short-circuit ITSC and open phase circuits in the stator or rotor windingsof wind turbines based on doubly-fed induction generator The principle of the suggestedtechnique is based on the acquisition of the stator and the rotor currents of a doubly-fed inductiongenerator with the aim to calculate the values of root mean square amplitude, in addition to theknowledge expressed in rules and membership function. This technique is verified usingsimulations performed via the model of doubly-fed induction generators built in MATLAB ®Simulink. Voir les détails
Mots clés : doubly-fed induction generator, DFIG, Fuzzy logic, Monitoring, Detection, faults, RMS
Waveguide Filter Modeling and Simulation using Mode-matching, FullwaveNetwork Analysis and Swarm Optimization
This paper presents the modeling ofwaveguide bandpass filter synthesis. It consists of acombination of the most appropriate and reliablemethods and techniques of analysis, simulation andoptimization used in determined order and leading to afast and accurate method of filter synthesis. An exampleof a forth-order filter synthesis is given, employing asymmetric configuration and symmetric response. Theobtained results, reference measurement and commercialsoftware simulator results are compared for validation. Voir les détails
Mots clés : filter, waveguide, Coupling matrix, Mode-matching, Segmentation method, Optimization techniques.
Type-2 Fuzzy Logic Predictive Control of a Grid Connected Wind Power Systems with Integrated Active Power Filter Capabilities
This paper proposes a real-time implementation of an optimal operation of a double stage grid connected wind power system incorporating an active power filter (APF). The system is used to supply the nonlinear loads with harmonics and reactive power compensation. On the generator side, a new adaptive neuro fuzzy inference system (ANFIS) based maximum power point tracking (MPPT) control is proposed to track the maximum wind power point regardless of wind speed fluctuations. Whereas on the grid side, a modified predictive current control (PCC) algorithm is used to control the APF, and allow to ensure both compensating harmonic currents and injecting the generated power into the grid. Also a type 2 fuzzy logic controller is used to control the DC-link capacitor in order to improve the dynamic response of the APF, and to ensure a well-smoothed DC-Link capacitor voltage. The gained benefits from these proposed control algorithms are the main contribution in this work. The proposed control scheme is implemented on a small-scale wind energy conversion system (WECS) controlled by a dSPACE 1104 card. Experimental results show that the proposed T2FLC maintains the DC-Link capacitor voltage within the limit for injecting the power into the grid. In addition, the PCC of the APF guarantees a flexible settlement of real power exchanges from the WECS to the grid with a high power factor operation. Voir les détails
Mots clés : Active power filter (APF), Adaptive neuro fuzzy inference system (ANFIS), Maximum Power Point Tracking (MPPT), Predictive current control (PCC), Type-2 fuzzy logic controller (T2FLC)
Analysis and experimental evaluation of shunt active power filter for power quality improvement based on predictive direct power control
This paper discusses the use of the concept of classical and predictive direct power control for shunt active power filter function. These strategies are used to improve the active power filter performance by compensation of the reactive power and the elimination of the harmonic currents drawn by non-linear loads. A theoretical analysis followed by a simulation using MATLAB/Simulink software for the studied techniques has been established. Moreover, two test benches have been carried out using the dSPACE card 1104 for the classic and predictive DPC control to evaluate the studied methods in real time. Obtained results are presented and compared in this paper to confirm the superiority of the predictive technique. To overcome the pollution problems caused by the consumption of fossil fuels, renewable energies are the alternatives recommended to ensure green energy. In the same context, the tested predictive filter can easily be supplied by a renewable energy source that will give its impact to enhance the power quality. Voir les détails
Mots clés : Harmonic pollution, Power quality, Direct power control, Predictive direct power control, Shunt active filter, Renewable energy source, power factor
Design and Experimental Validation of a Digital Predictive Controller for Variable-Speed Wind Turbine Systems
Advanced control algorithms must be used to make wind power generation truly cost effective and reliable. In this study, we develop a new and simple control scheme that employs model predictive control (MPC), which is used in permanent magnet synchronous generators and grid-connected inverters. The proposed control law is based on two points, namely, MPC-based torque?current control loop is used for the generator-side converter to reach the maximum power point of the wind turbine, and MPC-based direct power control loop is used for the grid-side converter to satisfy the grid code and help improve system stability. Moreover, a simple prediction scheme is developed for the direct-drive wind energy conversion system (WECS) to reduce the computation burden for real-time applications. A small-scale WECS laboratory prototype is built and evaluated to verify the validity of the developed control methods. Acceptable results are obtained from the real-time implementation of the proposed MPC methods for WECS. Voir les détails
Mots clés : Maximum Power Point Tracking (MPPT), Model predictive control (MPC), Permanent Magnet Synchronous Generator (PMSG), Wind Energy Conversion System (WECS)
The Performance of Some Implicit Region-Based ActiveContours in Segmenting and Restoring WeldingRadiographic Images
Several domains are based on image processing and analysis. One of them is the radiographicinspection which is used in Non Destructive Testing (NDT). Active contours, snakes ordeformable models are powerful techniques in image segmentation and restoration. According to theterm related to the input data (image to be treated) those functionals are ranked on two categories:edge-based models and region-based models. Previous studies point out the advantages of the regionbasedmodels over edge-based models. In this paper, we discuss and we summarize the strengths andweaknesses of four implicit region-based active contour models named: Piecewise Constant PC,Piecewise Smooth PS, Local Binary Fitting LBF and Global Local fitting energy GLF. After performingseveral experiments, we have concluded that all the models perform well with homogeneousimages. On the contrary when images are strongly inhomogeneous, the models based on global (PC)or local (LBF) statistic intensity fail to segment such images. The PS model with its great advantage inpreserving the contours has, as a drawback, the high CPU time consuming. The combination of localand global statistic image intensity gives to the GLF model the ability to better deal with such imagesin less CPU time. Voir les détails
Mots clés : segmentation, radiographic images, Level set, region-based active contour, PC, PS, LBF, GLF
Design and Real Time Implementation of Three-PhaseThree Switches Three Levels Vienna Recti?er Based onIntelligent Controllers
This paper treats the control of multilevel rectifier by applying the soft computing technique represented by the fuzzy logic. This latest, provides an inexpensive solution for controlling the ill-known complex systems, while relying on the imitation of human reasoning. In our case, the proposed intelligent controller aims at eliminating the current line harmonics, guaranteing an improved power factor, reducing the output voltage ripple and ensuring the balance between the two voltages across the two capacitors of Vienna rectifier. In order to evaluate the performance of the proposed control for Vienna rectifier, a comparative study in real time via the dSPACE card 1104 has been carried out between the traditional approach based on the conventional controllers and the new method using an intelligent controller. The experimental results confirm that the modified control approach has guaranteed a good quality of source currents in phase with the grid voltages and operation of the studied system with a power factor very close to unity. Furthermore, only one fuzzy controller used has ensured the regulation of the DC bus voltage, the minimization of the undulations for the two partial voltages and the improvement of the error of the voltage balance for the Vienna rectifier. Voir les détails
Mots clés : Vienna rectifier, Fuzzy logic controller, DC bus voltage ripple, Total harmonic distortion, Power factor correction
Diagnosis and classification using ANFIS approach ofstator and rotor faults in induction machine
Three-phase squirrel cage induction motors are one of the importantelements of the industrial production system, and are mostly used because oftheir robustness, reliability, relatively simple construction and their low cost.Nevertheless, during their function in different process, this machine types aresubmitted to external and internal stresses which can lead to several electricalor mechanical failures. In this paper, we proposed a reliable approach fordiagnosis and detection of stator short-circuit windings and rotor broken barsfaults in induction motor under varying load condition based on relative energyfor each level of stator current signal using wavelet packet decompositionwhich will be useful as data input of adaptive neuro-fuzzy inference system(ANFIS). The adaptive neuro-fuzzy inference system is able to identify theinduction motor and it is proven to be capable of detecting broken bars andstator short-circuit fault e with high precision. The diagnostic ANFIS algorithmis applicable to a variety of industrial process based on the induction machinefor detection and classified the any faults types. This approach is applied underthe MATLAB software®. Voir les détails
Mots clés : Induction machine, Detection, diagnosis, neuro-fuzzy, Monitoring
DIAGNOSTIC DES DEFAUTS MECANIQUES ETELECTROMAGNETIQUES SUR LES AEROGENERATEURS ÀBASE DE MACHINE ASYNCHRONE À DOUBLE ALIMENTATION
The use of doubly-fed induction machine in wind conversion systems occupies a verysignificant place. Therefore, the diagnosis of potential faults in these machines is nowadays a majorpriority for the industrialists in particular and for the scientists in general.Currently, the requirements of renewable energy, in terms of wind conversion system, is growingup due to the availability of the industrial processes became an economic argument than a meremarketing. However, the monitoring and the diagnosis require at the same time a better functionaland behavioral knowledge of the system in order to highlight, in an early stage, the conditionsleading to a failure situation.In this thesis, we are interested of the fault of the doubly-fed induction machine. Firstly, we willdevelop the doubly-fed induction machine model that can to represent the machine behavior invarious function modes and structural imbalances. Among the faults, the fault of static, dynamic andmixed eccentricity, and the phases openings faults, and the stator or rotor inter-turns short-circuit areconsidered.A spectral analysis of stator currents of the doubly-fed induction machine taken at the time ofthese faults will be presented subsequently.In the last part, we will develop an approach of monitoring allowing to obtain information on themachine state, the detection and the localization of the faults. Voir les détails
Mots clés : défauts mécaniques, électromagnétique, aérogénérateurs, GADA, modélisations
Contribution à l’Etude du Choix Optimal de l’Emplacement du Dispositif UPFC dans les Réseaux Electriques en Utilisant une des Méthodes Artificielles
With the increasing electric power demand, the operation of power system becomes more complex to operate within the indices power quality, and therefore will become less secure. The advent of Flexible Alternating Current Transmission Systems (FACTS) technology has coincided with the major restructuring of the electrical power industry; it can provide significant benefits in increasing system transmission capacity and power flow control flexibility and rapidity. Several types of FACTS exist and choosing the appropriate device depends on the objectives to reach. Unified Power Flow Controller (UPFC) is one of the most effective FACTS devices for enhancing power system security; however, to what extent the performance of UPFC can be brought out, it highly depends upon the location and parameter setting of this device in the system. A lot of research has been done on determining the optimal locations of FACTS devices in power systems. There are several methods permitting to find the optimal locations of FACTS devices according to specified criteria and constraints. Among these methods are found the Genetic Algorithm (GA) method. The latter is a global search and optimization technique which is based on the mechanisms of natural selection and genetics; it can search several possible solutions simultaneously and do not require any prior knowledge of the objective function. In this thesis, genetic algorithms technique is used to solve the problem of choosing the location and rating of FACTS to install. Five types of FACTS devices have been used in this study namely: SVC, TCSC, TCVR, TCPST and UPFC. These FACTS devices are used to maximize the system loadability in the network. Their position and size are determined using coefficients calculated when the load increases. To validate the efficacy of the technique used, has been applied on many IEEE standard electrical network test (14, 30 and 57 bus) using the MATLAB program. Voir les détails
Mots clés : Indices power quality, FACTS, UPFC, GA, global optimization, objective function, SVC, TCSC, TCVR, TCPST, loadability, MATLAB program