67 research outputs found
Sensors placement for the faults detection and isolation based on bridge linked configuration of photovoltaic array
Introduction. The photovoltaic market has been increased over the last decade at a remarkable pace even during difficult economic times. Photovoltaic energy production becomes widely used because of its advantages as a renewable and clean energy source. It is eco-friendly, inexhaustible, easy to install, and the manufacturing time is relatively short. Photovoltaic modules have a theoretical lifespan of approximately 20 years. In real-life and for several reasons, some photovoltaic modules start to fail after being used for a period of 8 to 10 years. Therefore, to ensure safe and reliable operation of photovoltaic power plants in a timely manner, a monitoring system must be established in order to detect, isolate and resolve faults. The novelty of the proposed work consists in the development of a new model of sensors placement for faults detection in a photovoltaic system. The fault can be detected accurately after the analysis of changes in measured quantities. Purpose. Analysis of the possibility of the number and the position of the sensors into the strings in function of different faults. Methods. This new method is adapted to the bridge linked configuration. It can detect and locate failure points quickly and accurately by comparing the measured values. Results. The feasibility of the chosen model is proven by the simulation results under MATLAB/Simulink environment for several types of faults such as short-circuit current, open circuit voltage in the photovoltaic modules, partially and completely shaded cell and module.Вступ. Ринок фотоелектричної енергії зріс за останнє десятиліття неймовірними темпами навіть у складні економічні часи. Виробництво фотоелектричної енергії стає широко використовуваним через його переваги як відновлюваного та чистого джерела енергії. Він екологічно чистий, невичерпний, простий в установці, а час виготовлення відносно короткий. Фотоелектричні модулі мають теоретичний термін служби приблизно 20 років. У реальному житті з кількох причин деякі фотоелектричні модулі починають виходити з ладу після використання протягом 8-10 років. Тому для своєчасного забезпечення безпечної та надійної роботи фотоелектричних електростанцій необхідно створити систему моніторингу для виявлення, локалізації та усунення несправностей. Новизна запропонованої роботи полягає в розробці нової моделі розміщення датчиків для виявлення несправностей у фотоелектричній системі. Несправність можна точно виявити після аналізу змін вимірюваних величин. Мета. Аналіз можливості кількості та розташування датчиків у рядках залежно від різних несправностей. Методи. Цей новий метод адаптовано до конфігурації, пов’язаної з мостом. Він може швидко й точно виявляти та локалізувати точки збою, порівнюючи виміряні значення. Результати. Здійсненність обраної моделі підтверджується результатами моделювання в середовищі MATLAB/Simulink для кількох типів несправностей, таких як струм короткого замикання, напруга холостого ходу в фотоелектричних модулях, частково та повністю затемнена комірка та модуль
Effect of High-k Oxide on Double Gate Transistor Embedded in RF Colpitts Oscillator
This paper present a comprehensive analysis of LC Colpitts Oscillator built around a DGMOS (Double
Gate Metal Oxide Semiconductor) transistor using high-k technology. A mixed- mode simulation is involved,
applying a quantum model to the device whereas the rest of the considered circuit is governed by
Kirchhoff‟s laws. The quantum device model correspond to 2D numerical calculations based on self- consistent
codes coupling Poisson and Schrödinger equation along the transport direction, considering an effective
mass approximation. A comparison with Drift Diffusion model (DDM) is made in order to point out
importance of quantum effect in this nanometer device. The impact of high-k oxide gate is investigated and
analyzed; the results confirm that the high-k is an interesting alternative to reduce tunneling gate current
of the DGMOS transistor but reach the same drain one. Considering the oscillator, our goal is focused on
the analysis of its phase noise.
The Linear Time Variant (LTV) model of phase noise is considered. It is based on the Impulse Sensitivity
Function (ISF) which describes carefully the sensitivity of an oscillator to a parasite impulse current
injection in different nodes of the circuit. The obtained results pointed out that the ISF function is sinusoidal
and its period is nearly the same of the oscillator output signal for different dielectric oxide. It also
states that the phase noise of a Colpitts oscillator is not affected by the use of the high-k materials. Finally
this method, if extended, is a good tool to investigate a perturbation response on such circuits
Implementation of MPPT Algorithm and Supervision of Shading on Photovoltaic Module
This paper presents an implementation of MPPT (maximum power point tracking) algorithm based on real-time measurements and on model-based simulation. For the supervision of a photovoltaic module, different cases of shading are used. Attention was given on advanced control for the supervision of a photovoltaic system according to the need to maximize energy output. Experimental results verified the performance and the feasibility of the proposed system
Techno-Economic Feasibility Study of Investigation of Renewable Energy System for Rural Electrification in South Algeria
This work aims to consider the combination of different technologies regarding energy production and management with four possible configurations. We present an energy management algorithm to detect the best design and the best configuration from the combination of different sources. This combination allows us to produce the necessary electrical energy for supplying habitation without interruption. A comparative study is conducted among the different combinations on the basis of the cost of energy, diesel consumption, diesel price, capital cost, replacement cost, operation, and maintenance cost and greenhouse gas emission. Sensitivity analysis is also performed
Photovoltaic fault diagnosis algorithm using fuzzy logic controller based on calculating distortion ratio of values
Introduction. The efficiency of solar energy systems in producing electricity in a clean way. Reliance on it in industrial and domestic systems has led to the emergence of malfunctions in its facilities. During the operating period, these systems deteriorate, and this requires the development of a diagnostic system aimed at maintaining energy production at a maximum rate by detecting faults as soon as possible and addressing them. Goal. This work proposes the development of an algorithm to detect faults in the photovoltaic system, which based on fuzzy logic. Novelty. Calculate the distortion ratio of the voltage and current values resulting from each element in the photovoltaic system and processing it by the fuzzy logic controller, which leads to determining the nature of the fault. Results. As show in results using fuzzy logic control by calculating the distortion ratio of the voltage and current detect 12 faults in photovoltaic array, converter DC-DC and battery
Comprehensive review of radial distribution test systems for power system distribution education and research
A comprehensive review of existing radial distribution test systems available for power system distribution research is presented. The review can be used to establish a record of cases suitable for distribution operation and planning studies. The importance of the distribution system, the structure of the system in the grid, and various configurations of the distribution network are discussed. The primary requirement of a distribution network is highlighted to underline the important system parameters that should be considered in the design and planning stages. Various research related to the distribution network can be conducted, such as load flow algorithms, optimal incorporation of distributed generation, network reconfiguration, and optimal capacitor allocation, such as important details pertaining to each test system are given. Additional information, such as active and reactive loads and losses, minimum voltage values, and bus location with the weakest voltage values, is provided. Application of the reviewed works based on the test system is tabulated and presented. The information presented in this paper will be beneficial for future research in distribution system design and planning
Effect of High-k Oxide on Double Gate Transistor Embedded in RF Colpitts Oscillator
This paper present a comprehensive analysis of LC Colpitts Oscillator built around a DGMOS (Double
Gate Metal Oxide Semiconductor) transistor using high-k technology. A mixed- mode simulation is involved,
applying a quantum model to the device whereas the rest of the considered circuit is governed by
Kirchhoff‟s laws. The quantum device model correspond to 2D numerical calculations based on self- consistent
codes coupling Poisson and Schrödinger equation along the transport direction, considering an effective
mass approximation. A comparison with Drift Diffusion model (DDM) is made in order to point out
importance of quantum effect in this nanometer device. The impact of high-k oxide gate is investigated and
analyzed; the results confirm that the high-k is an interesting alternative to reduce tunneling gate current
of the DGMOS transistor but reach the same drain one. Considering the oscillator, our goal is focused on
the analysis of its phase noise.
The Linear Time Variant (LTV) model of phase noise is considered. It is based on the Impulse Sensitivity
Function (ISF) which describes carefully the sensitivity of an oscillator to a parasite impulse current
injection in different nodes of the circuit. The obtained results pointed out that the ISF function is sinusoidal
and its period is nearly the same of the oscillator output signal for different dielectric oxide. It also
states that the phase noise of a Colpitts oscillator is not affected by the use of the high-k materials. Finally
this method, if extended, is a good tool to investigate a perturbation response on such circuits
Modélisation électrique de transistors bipolaires radiofréquences a hétérojonction Compatibles CMOS
Nano-device Oscillators Modeling: Noise ; 205 pages
International audienceThe trend in modern communication circuits is towards higher data rates and better bandwidth utilization. Very stringent requirements are placed on the spectral purity of oscillators increasing the needs on the local oscillator phase noise. [1-2] Mostly, noise is a sensitive measure to defects and non-ideality in semiconductor devices, which can impact device and circuit performances [3]. Noise in devices can be up-converted in phase noise in oscillators and reduce the achievable spectral purity in communications systems. SiGe technology is today one of the mainstream semiconductor technologies used in RF and microwave applications, which not only offers to bipolar transistor higher speed performance, but also lower noise and better linearity [4-5]. The work is mainly focused on nanometric oscillators, like Double gate MOS (DGMOS) or RF Hetrojunction Bipolar Transistor (HBT) Colpitts oscillator, containing Si/SiGe heterojunction bipolar transistor compatible with a CMOS technology, Resonat Tuneling Diode (RTD), Single Electron Transistor (SET). First of all, we state a study of electrical characteristics of specified heterojunction bipolar transistors. We report the electric behaviour of a SiGe HBT with the presence of electrically active defects induced during extrinsic base implantation. Next, we are interested to substrate noise and their effects on the phase perturbation of oscillator. We study the contribution of device implantation defect to the output noise of oscillator. These defects responsible for current fluctuations at the origin of noise in device have an dramatic effect on phase noise of oscillator. We insist on the importance of th substrate behavior, especially in the radiofrequency range Finally we investigate phase noise of an oscillator; the study was based on linear time varying model of phase noise developed by Hajimiri [6]. This model relates the phase noise with the time-variant nature of the oscillator and provides a clear physical mechanism of phase noise generation. This way, an enhanced impulse sensitivity function (ISF) technique is proposed to describe the susceptibility of an oscillator to noise as a function of time. This work presents a mixed mode simulations of a radiofrequency LC oscillator implemented in Silicon Germanium technology. As first, we have investigated the effect of electrically active defects induced during extrinsic base implantation on electrical characteristics of the SiGe HBT. If static performances of the HBT are strongly penalized by the presence of these defects, conversely the dynamic performances remain unchanged. Second we are interested to analyse the influence of electrically active implantation defects on an actual 4 GHz LC oscillator phase noise. The energy position of trap in the semiconductor gap has a real influence on the phase shift of output oscillator waveform. The simulation predicts an increase in the phase shift of output waveform with defect energy. Finally, based on LTV model which makes use of the impulse sensitivity function (ISF), we have investigated the susceptibility of a radiofrequency oscillator to noisy disturbance sources. Through impulse sensitivity function (ISF) analyze, we have verified the time variance of oscillator, and described the sensitivity of the oscillator over time. The oscillator is rather sensitive at certain instances of the delay and less sensitive at other instances
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