3,005 research outputs found

    Automated monitor and control for deep space network subsystems

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    The problem of automating monitor and control loops for Deep Space Network (DSN) subsystems is considered and an overview of currently available automation techniques is given. The use of standard numerical models, knowledge-based systems, and neural networks is considered. It is argued that none of these techniques alone possess sufficient generality to deal with the demands imposed by the DSN environment. However, it is shown that schemes that integrate the better aspects of each approach and are referenced to a formal system model show considerable promise, although such an integrated technology is not yet available for implementation. Frequent reference is made to the receiver subsystem since this work was largely motivated by experience in developing an automated monitor and control loop for the advanced receiver

    Advanced control techniques for modern inertia based inverters

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    ”In this research three artificial intelligent (AI)-based techniques are proposed to regulate the voltage and frequency of a grid-connected inverter. The increase in the penetration of renewable energy sources (RESs) into the power grid has led to the increase in the penetration of fast-responding inertia-less power converters. The increase in the penetration of these power electronics converters changes the nature of the conventional grid, in which the existing kinetic inertia in the rotating parts of the enormous generators plays a vital role. The concept of virtual inertia control scheme is proposed to make the behavior of grid connected inverters more similar to the synchronous generators, by mimicking the mechanical behavior of a synchronous generator. Conventional control techniques lack to perform optimally in nonlinear, uncertain, inaccurate power grids. Besides, the decoupled control assumption in conventional VSGs makes them nonoptimal in resistive grids. The neural network predictive controller, the heuristic dynamic programming, and the dual heuristic dynamic programming techniques are presented in this research to overcome the draw backs of conventional VSGs. The nonlinear characteristics of neural networks, and the online training enable the proposed methods to perform as robust and optimal controllers. The simulation and the experimental laboratory prototype results are provided to demonstrate the effectiveness of the proposed techniques”--Abstract, page iv

    Artificial Neural Network Active Power Filter with Immunity in Distributed Generation

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    With an electrical grid shifting toward Distributed Generation (DG), the emerging use of renewable energy resources is continuously creating challenges to maintain an acceptable electrical power quality thought-out the grid; Therefore, in an energy market where loads are becoming more and more sensitive in a distributed generation filled with polluting nonlinear loads, power quality improvement devices such Active Power Filters (APFs) have to evolve to meet the new standards, since theirs conventional control strategies can't properly operate when multiple power quality problems happens at once, even the one using AI based control as it will be proven in this paper. In this paper a neural network based Active Power Filter will be tested in a DG environment where both current and voltage harmonics, along with fast frequency variation occurs, we will see how the PLL can downgrade its performances enormously under such hostile conditions, We propose to solve this problem by replacing the conventional PLL with a nonlinear least square (NLS) frequency estimator, this novel NLS-ADALINE SAPF is immune in high DG penetration environment, as it will be tested and validated experimentally on an Opal-RT OP5600 FPGA based real-time simulator

    Study on Adaptive Harmonic Extraction Approaches in Active Power Filter Applications

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    Active power filter (APF) has now become a mature technology for harmonic and reactive power compensations in two-wire (single phase), three-wire (three phase without neutral), and four-wire (three phase with neutral) ac power networks with nonlinear loads. This paper presents a study on three different adaptive algorithms for active power filtering applications. These algorithms are adaptive linear combiner (ADALINE), least mean square adaptive notch filter (ANF-LMS), and recursive least square adaptive notch filter (ANF-RLS). In this paper, these approaches are employed for extracting load harmonic currents. The important issues associated with adaptive methods are accuracy and prediction speed. These issues will be addressed in the paper. Simulations using MATLAB/Simulink are presented to clarify the algorithms

    On the Enhancement of Generalized Integrator-based Adaptive Filter Dynamic Tuning Range

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    SIECI “SMART GRIDS” – WYZWANIA SYNCHRONIZACJI

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    This paper deals with crucial aspect of synchronization in modern power grids. It presents the concept of intelligent networks (“smart grids”), as the future of today’s grid infrastructure. The diversity of different grid codes in regards to the synchronization requirements for different Transmission System Operators (TSO) is discussed. This paper shows the applications of synchronizing algorithms, their role in power grid system.. The methods are classified according to application, the reference frame used and the possibility of using them in single and three phase systems. Proper selection of synchronization algorithms to meet the requirements of TSO’s calls for creation of appropriate evaluation methods. For this reason, at the end of the article quality criteria for the evaluation of synchronizing algorithms were proposed and explained in detail. Finally, the last section states what are the most commonly used methods for grid synchronization.Niniejszy artykuł zajmuje się kluczowym aspektem, jakim jest synchronizacja w nowoczesnych sieciach elektroenergetycznych. Przedstawia on koncepcję sieci inteligentnych („smart grids”),uważaną jako przyszłość dzisiejszej infrastruktury sieciowej. Omówiono w nim różnice w zakresie przepisów sieci energetycznych różnych operatorów w odniesieniu do wymagań synchronizacji z siecią. Opisane metody sklasyfikowano według ich typowych aplikacji, zastosowanego układu odniesienia i możliwości zastosowania w systemie jedno- lub trójfazowym. Odpowiedni dobór algorytmów synchronizacji by spełnić wymagania TSO postuluje powstanie właściwych  metod oceny tych algorytmów. Z tego powodu ostatni punkt artykułu opisuje i wyjaśnia szczegółowo dobrane kryteria oceny jakości algorytmów do synchronizacji. W ostatniej sekcji artykułu pokazano jakie są najczęściej stosowane metody do synchronizacji z siecią

    CONTROLLERS AND METHODS FOR DIFFERENT ELECTRICAL MEASUREMENTS IN SYNCHRONIZATION OF RENEWABLE ENERGY SOURCES FOR GRID CONNECTIVITY: A REVIEW

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    In this paper, different controllers used in synchronization of renewable energy sources are studied. A study regarding the use of artificial intelligence in synchronization of grid connected power converters, efficient method for phase angle detection, frequency variation detection and good performance during voltage depression etc  carried out here. Importance of hybrid controllers over conventional controllers is also presented. Possibility of  Z source T type inverter as an alternate solution to DC-DC converter is explored based on existing works
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