Modeling and Control of a UPFC System Using Pole-Placement and Hinf Robust Control Techniques

This is an open access article distributed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International license (CC BY-NC-ND 4.0) https://creativecommons.org/licenses/by-nc-nd/4.0/FACTS (Flexible AC Transmission Systems) technology has now been accepted as a potential solution to the stability problem and load flow. The Unified Power Flow Controller (UPFC) is considered to be the most powerful and versatile among all FACTS devices. This paper presents the modeling and control of a UPFC system using pole-placement and H robust control techniques. A simulation study using Matlab/Simulink is presented to compare the performance of these control strategies and their robustness with respect to variations is the system parameters such as the inductance of the transmission line.Peer reviewe

Optimal frequency control in microgrid system using fractional order PID controller using Krill Herd algorithm

This paper investigates the use of fractional order Proportional, Integral and Derivative (FOPID) controllers for the frequency and power regulation in a microgrid power system. The proposed microgrid system composes of renewable energy resources such as solar and wind generators, diesel engine generators as a secondary source to support the principle generators, and along with different energy storage devices like fuel cell, battery and flywheel. Due to the intermittent nature of integrated renewable energy like wind turbine and photovoltaic generators, which depend on the weather conditions and climate change this affects the microgrid stability by considered fluctuation in frequency and power deviations which can be improved using the selected controller. The fractional-order controller has five parameters in comparison with the classical PID controller, and that makes it more flexible and robust against the microgrid perturbation. The Fractional Order PID controller parameters are optimized using a new optimization technique called Krill Herd which selected as a suitable optimization method in comparison with other techniques like Particle Swarm Optimization. The results show better performance of this system using the fractional order PID controller-based Krill Herd algorithm by eliminates the fluctuations in frequency and power deviation in comparison with the classical PID controller. The obtained results are compared with the fractional order PID controller optimized using Particle Swarm Optimization. The proposed system is simulated under nominal conditions and using the disconnecting of storage devices like battery and Flywheel system in order to test the robustness of the proposed methods and the obtained results are compared.У статті досліджено використання регуляторів пропорційного, інтегрального та похідного дробового порядку (FOPID) для регулювання частоти та потужності в електромережі. Запропонована мікромережева система складається з поновлюваних джерел енергії, таких як сонячні та вітрогенератори, дизельних генераторів як вторинного джерела для підтримки основних генераторів, а також з різних пристроїв для накопичування енергії, таких як паливна батарея, акумулятор і маховик. Через переривчасту природу інтегрованої відновлювальної енергії, наприклад, вітрогенераторів та фотоелектричних генераторів, які залежать від погодних умов та зміни клімату, це впливає на стабільність мікромережі, враховуючи коливання частоти та відхилення потужності, які можна поліпшити за допомогою вибраного контролера. Контролер дробового порядку має п’ять параметрів порівняно з класичним PID-контролером, що робить його більш гнучким та надійним щодо збурень мікромережі. Параметри PID-контролера дробового порядку оптимізовані за допомогою нової методики оптимізації під назвою «зграя криля», яка обрана як підходящий метод оптимізації порівняно з іншими методами, такими як оптимізація методом рою частинок. Результати показують кращі показники роботи цієї системи за допомогою алгоритму «зграя криля», заснованого на PID-контролері дробового порядку, виключаючи коливання частоти та відхилення потужності порівняно з класичним PID-контролером. Отримані результати порівнюються з PID-контролером дробового порядку, оптимізованим за допомогою оптимізації методом рою частинок. Запропонована система моделюється в номінальному режимі роботи та використовує відключення накопичувальних пристроїв, таких як акумулятор та маховик, щоб перевірити надійність запропонованих методів та порівняти отримані результати

Diversité floristique du Parc National du Haut Atlas Oriental et des Massifs ayachi et Maâsker (Maroc).

Diversité floristique du Parc National du Haut Atlas Oriental et des massifs Ayachi et Maâsker (Maroc). Etant donné la rareté des études sur le Parc National du Haut Atlas Oriental et les massifs Ayachi et Maâsker, les connaissances sur la diversité floristique de ces régions, très accidentées, étaient très insuffisantes et fragmentaires. Actuellement la flore vasculaire du Parc, jbels Ayachi et Maâsker est estimée respectivement à 227, 140 et 96 espèces; la flore rare, menacée et/ou endémique constitue une part importante. Le nombre d�endémiques dans le Parc (espèces et sous espèces) représente 6.8 % de l�ensemble des endémiques marocaines. Ce nombre est très important dans l�Ayachi avec 7.5 %. Dans le Maâsker, le nombre d�endémiques est évalué à 3.9 % de l�ensemble des endémiques marocaines. La flore rare (espèces et sous-espèces) est représentée par 3.6 % de la flore totale du Parc, 4 % de la flore totale du jbel Ayachi et 4 % de la flore totale du jbel Maâsker. Par contre le taux de la flore très rare est faible, respectivement de l�ordre de 1.9 %, 2 % et 2.4 %.Flora diversity of the National Park of the Eastern High Atlas and the massifs Ayachi and Mâasker (Morocco). Considering the rare studies on the Eastern High Atlas National Park, Ayachi and Mâasker mountains, the knowledge on the flora diversity of these regions were very insufficient.Their flora is estimated currently 227, 140 and 96 species. The rare flora, threatened and/or endemic constitutes an important part. The number of endemics in the Park (species and subspecies) represents 6.8% of the endemics of Morocco. This number is very important in Ayachi (7.5%). In Maasker, the number of endemics is about 3.9% of the endemic of Morocco. The rare flora (species and subspecies) in the Park, Ayachi and Maasker is represented respectively by 3.6%, 4%, and 4%. On the other hand the very rare flora is poor respectively 1.9%, 2% and 2.4%

A new robust control using adaptive fuzzy sliding mode control for a DFIG supplied by a 19-level inverter with less number of switches

This article presents the powers control of a variable speed wind turbine based on a doubly fed induction generator (DFIG) because of their advantages in terms of economy and control. The considered system consists of a DFIG whose stator is connected directly to the electrical network and its rotor is supplied by a 19-level inverter with less number of switches for minimize the harmonics absorbed by the DFIG, reducing switching frequency, high power electronic applications because of their ability to generate a very good quality of waveforms, and their low voltage stress across the power devices. In order to control independently active and reactive powers provided by the stator side of the DFIG to the grid and ensure high performance and a better execution, three types of robust controllers have been studied and compared in terms of power reference tracking, response to sudden speed variations, sensitivity to perturbations and robustness against machine parameters variations.В статье описывается управление мощностью ветряной турбины переменной скорости на основе асинхронного генератора двойного питания ввиду их преимуществ с точки зрения экономичности и управления. Рассматриваемая система состоит из асинхронного генератора двойного питания, статор которого подключен непосредственно к электрической сети, а его ротор питается от 19-уровневого инвертора с меньшим количеством коммутаторов для минимизации гармоник, поглощаемых генератором, уменьшая частоту переключения, и устройств силовой электроники вследствие их способности генерировать высокое качество сигналов и низкого уровня напряжения на них. Чтобы независимо управлять активной и реактивной мощностью, подаваемой стороной статора указанного генератора в сеть, и обеспечивать высокую производительность и лучшее конструктивное исполнение, изучены и сопоставлены три типа робастных контроллеров с точки зрения отслеживания мощности, реакции на внезапное изменение скорости, чувствительности к возмущениям и устойчивости к изменениям параметров машины

ANALYSE MULTI FRACTALE DES ÉCHOS RADAR PAR LA MÉTHODE DES MAXIMUMS DES MODULES DE LA TRANSFORMÉE EN ONDELETTE (MMTO) 2D POUR LES SITES DE BORDEAUX (FRANCE), SÉTIF (ALGÉRIE) : APPLICATION À L'ÉLIMINATION DES ÉCHOS PARASITES

International audienceIn this work, the 2D-WTMM multifractal approach was applied to analysis the radar echoes, and to identify the unwanted echoes coming from terrestrial surface. With this intention, we considered radar images taken from two areas where different climates and relief prevail. We showed that almost Anaprops are characterized by a monofractal spectrum contrary to the echoes of precipitations which present a multifractal character. Moreover, we showed that the Holder coefficient and the combination of the spectrum mode and density of skeleton per pixel present robust factors to discriminate between the two types of echoes. Indeed, the unwanted echoes are practically eliminated at 98 per cent whereas the echoes of precipitation are almost preserved at 98,2 per cent. Also, we showed that the error between the measured intensity on the ground and the estimated intensity after treatment of the unwanted echoes does not exceed 5% for the Sétif site. Because the computation time is three minutes, the radar images can be processed in real-time.Dans le présent travail, l'approche MMTO-2d est appliquée pour l'analyse multi fractale des échos radar et l'identification des échos parasites en provenance de la surface terrestre. Pour ce faire, nous avons considéré des images radar prises dans deux régions où prévalent des climats et des reliefs différents. Il s'agit des sites de Sétif (Algérie) et Bordeaux (France). Nous avons montré que la plupart des Anaprops sont caractérisés par un spectre monofractal contrairement aux échos de précipitations qui présentent un caractère multi fractal. En outre, nous avons montré que le coefficient d'Holder ou la combinaison mode du spectre et densité de squelette par pixel se présentent comme des facteurs robustes de discrimination entre les deux types d'échos. En effet, les échos parasites sont pratiquement éliminés à 98% alors que les échos de précipitation sont quasiment conservés à 98,2%. Aussi, nous avons montré que l'erreur entre l'intensité mesurée au sol et estimée après traitement des échos parasites ne dépasse pas 5% pour le site de Sétif. Etant donné que le temps de traitement est égal à trois minutes, les images radar peuvent être traitées en temps réel

MASCULINIDAD VERSUS FEMINIDAD EN LAS PAREMIAS HASSANÍES Y SU TRADUCCIÓN AL ESPAÑOL

The undervaluation of women and their relegation to second place with regards to men, has been constant throughout history. The predominance of man is very much present within the popular folklore of every nation in our world today. Therefore, the current study focuses on Hassani proverbs regarding both men and women in order to see how they interact with each other and to examine the everyday lives of women as represented within these proverbs. An attempt will also be made, to the greatest possible extent, to translate the selected proverbs into Spanish literally, and alsoprovide their literal or conceptual equivalents. This will thus enable us, though on a small scale, to establish relationships of similarities and differences between the treatment of women and their status in both Spanish and Hassani proverbs.La infravaloración de la mujer y su relegación a una segunda posición con respecto al hombre ha sido una constante a lo largo de la historia. El predominio del hombre está muy presente en el folclore popular de cada nación en el mundo actual. Es por ello que nos vamos a interesar, en el presente trabajo, por las paremias de hassaniyya relativas tanto al hombre como a la mujer con el fin de ver cómo se relacionan mutuamente y arrojar luz sobre la vida cotidiana de la mujer en el refranero hassaní. Intentaremos también, en la medida de lo posible, traducir al español las paremias objeto de estudio literalmente, además de establecer su correspondencia literal o conceptual. Ello nos permitirá, aunque a pequeña escala, establecer relaciones de diferencias y semejanzas entre los tratamientos de la mujer y su condición en los refraneros hassaní y español

A note on void ratio of fibre-reinforced soils

This technical note extends the concept of void ratio, presented traditionally in soil mechanics, for fibre-reinforced soils. Phase relationships related to the void ratio of fibre-reinforced soils are presented along with their definitions. A simple analytical model verified with experimental data for estimating the void ratio of fibre-reinforced soils is developed which can be used to express the compressibility of fibre-reinforced soils in geotechnical engineering applications. The results indicate that the void ratio of fibre-reinforced soils is dependent on the volume ratio of fibre-soil solid

A pattern-oriented and model-driven architecture for interactive systems

Day-to-day experiences suggest that it is not enough to approach a complex design equipped with design tips, guidelines, and hints. Developers must also be able to use proven solutions emerging from the best design practices to solve new design challenges. Without these, the designer is unable to properly apply guidelines or take full advantage of the power of technology, resulting therefore in poor performance, poor scalability, and poor usability. Furthermore, the designer might "reinvent the wheel" when attempting to implement a design solution. A number of design problems continue to arise, such as: (1) decoupling the various aspects of interactive systems (for example, business logic, the UI, navigation, and information architecture) and (2) isolating platform specifics from the concerns common to all interactive systems. In the context of a proposal for a Pattern-Oriented and Model-driven Architecture (POMA) for interactive systems, this thesis identifies an extensive list of pattern categories and types of models aimed at providing a pool of proven solutions to these problems. The models of patterns span several levels of abstraction, such as domain, task, dialog, presentation and layout. The proposed POMA architecture illustrates how several individual models can be combined at different levels of abstraction into heterogeneous structures which can then be used as building blocks in the development of interactive systems. This document is divided into six chapters: the first chapter presents a background and related work on "Patterns" in general and on various architectures for interactive systems development such as "N-tiers architectures", "Pattern-Oriented Design" (POD), "Pattern- Supported Approach" (PSA), and "Model-Driven Architecture" (MDA). The second chapter introduces the research topic with its objectives, its limits, the research methodology, and research steps. The third chapter describes primarily the most important parts of the research which is the development of a new architecture called Pattern-Oriented and Model-Driven Architecture, facilitating the development of interactive systems including fundamentals and key concepts, an overview, justifications versus N-tiers, POD, PSA, and MDA architectures and specifications. The fourth chapter describes architectural levels and categories of patterns used in POMA. The fifth chapter describes the categories of models used in POMA. The sixth chapter presents an exploratory case study applied to the architecture proposed in this research. The last chapter presents a conclusion on this research work and its expected evolution in the future