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EN
These Applications of fractional calculus are becoming more and more effective, adaptable, and have produced positive outcomes in a variety of engineering and scientific domains. In this paper, a fuzzy fractional-order PI-based control approach for grid-connected photovoltaic (PV) systems is presented. The various advantages of multi-level inverters (MLIs) in industrial and grid-connected applications have resulted to their increasing application in recent years. A five-level neutral point (NPC) inverter is used to integrate PV electricity into the electrical grid with minimal harmonic distortions and highest power capacity. The output voltage of the inverter must be maintained in order to connect to a grid, even though that the photovoltaic output voltage varies considerably with solar radiation. To achieve this, three fuzzy fractional order PI (FFOPI)controllers were used to control the inverter output voltage (Vdc), direct current (Id), and quadratic current (Iq) around a reference values. A further comparison is made with the fuzzy PI (FPI). According to research, the FFOPI controller outperforms the FPI controller in terms of performance.
PL
Te zastosowania rachunku ułamkowego stają się coraz bardziej efektywne, elastyczne i dają pozytywne rezultaty w różnych dziedzinach inżynierii i nauki. W tym artykule przedstawiono podejście oparte na rozmytym ułamkowym rzędzie sterowania PI dla systemów fotowoltaicznych (PV) podłączonych do sieci. Różne zalety falowników wielopoziomowych (MLI) w zastosowaniach przemysłowych i podłączonych do sieci spowodowały ich rosnące zastosowanie w ostatnich latach. Falownik z pięciopoziomowym punktem neutralnym (NPC) służy do włączania energii elektrycznej z fotowoltaiki do sieci elektrycznej przy minimalnych zniekształceniach harmonicznych i najwyższej mocy. Napięcie wyjściowe falownika musi być utrzymywane w celu podłączenia do sieci, mimo że napięcie wyjściowe fotowoltaiki znacznie się zmienia w zależności od promieniowania słonecznego. Aby to osiągnąć, zastosowano trzy rozmyte regulatory PI ułamkowego rzędu (FFOPI) do sterowania napięciem wyjściowym falownika (Vdc), prądem stałym (Id) i prądem kwadratowym (Iq) wokół wartości odniesienia. Dalsze porównanie przeprowadza się z rozmytym PI (FPI). Według badań kontroler FFOPI przewyższa kontroler FPI pod względem wydajnoś.
EN
In this paper, a deadbeat control technique for single-phase inverters used in UPS applications is presented. For the suggested control approach to maintain sinusoidal output voltage for high dynamic performance even with load fluctuations, measurements of capacitor current and output voltage are necessary. By reducing the error between the output voltage and the voltage reference without adding more current sensors, the deadbeat controller improves the performance of the proposed controller. It also reduces load voltage distortion and restores the system state in the event of an external shutdown-loop road interference. We suggest a capacitor current estimation based on the Luenberger observer to address this flaw. PROCESSOR-IN-THE-LOOP The "P.I.L" test method, which can be thought of as an expensive system, enables us to create and evaluate controllers by running built-in C code on the DSP scheduled for the controller during simulated PSIM power phase control. To address this drawback, we propose a capacitor current estimation based on the Luenberger observer.
PL
W artykule przedstawiono algorytm sterowania martwym uderzeniem falowników jednofazowych do zastosowań w systemach zasilania awaryjnego (UPS). Proponowana metoda sterowania wymaga pomiaru prądu kondensatora i napięcia wyjściowego w celu utrzymania sinusoidalnego napięcia wyjściowego w celu uzyskania wysokiej wydajności dynamicznej nawet przy zmianach obciążenia. liczbę czujników prądu, a także eliminuje zniekształcenia napięcia obciążenia i przywraca stan systemu w przypadku zewnętrznej ingerencji w pętlę wyłączania drogowego. Aby rozwiązać ten problem, proponujemy oszacowanie prądu kondensatora na podstawie obserwatora Luenbergera. PROCESOR-W-PĘTLI „P.I.L” to metoda testowa, która pozwala nam tworzyć i oceniać kontrolery poprzez uruchomienie wbudowanego kodu C na DSP zaplanowanym dla kontrolera podczas symulowanej kontroli fazy mocy PSIM, co można uznać za kosztowny system , aby poradzić sobie z tą wadą, proponujemy oszacowanie prądu kondensatora na podstawie obserwatora Luenbergera.
EN
Due to its multiple advantages in industrial and grid-connected applications, Multi-Level Inverters (MLIs) have increased in popularity in recent years. To improve the efficiency of a grid-connected PV system's integrated multi-level inverter fractional order PI (FOPI) controllers are used to describe the control process. The control system is made up of three control loops based on FOPI controllers: one for controlling the intermediate circuit voltage (Vdc) and the other two for controlling the direct and quadratic currents (Id, Iq) supplied by the multilevel inverter. The proposed controller parameters (Kp, KI, λ) must be selected in order to increase the efficiency of the multi-level inverter while decreasing the total harmonic distortion (THD) of the output current of the inverter as well as voltage. For this we used three meta-heuristic algorithms (PSO, ABC, GWO). The performance of the three controllers PSO-FOPI, ABC-FOPI and GWO-FOPI controller is compared. The findings showed that GWO-FOPI performs better than the other PSO-FOPI and ABC-FOPI in accuracy and total harmonic distortion THD term. The simulation will be conducted using Matlab/Simulink.
EN
The main insulation layer is the most important layer of the high-voltage cable, and the quality of this material directly affects the life of the cable. It is also known that contamination, porosity and associated partial discharges in the insulation can affect the service life of cables. In this paper, we use the COMSOL Multiphysics software, which is based on the finite element method in AC/DC, 2D electrostatic. Our study shows the effect of heterogeneous cavities on the functioning of electrical cables. This work contains the study of electric field distribution and potential of a model of high voltage cable; we took into account the absence and the presence of heterogeneous cavities. The study was conducted using numerical results with mathematical validation. The obtained results are considered satisfactory, favorable and very promising.
EN
The knowledge of the behavior of both the electric potential and electric field is one of the main factors needed when designing an insulator. Using AutoCAD software a 2D cap and pin 1512L insulator model was created in the clean state and under pollution from one to five insulators separately making a chain of insulators for a total of 10 models. Later they are imported to COMSOL Multiphysics 5.6 software, simulations of the 1512L insulator were made to see the effect the pollution has and the differences that occur on the distribution with the addition of more insulators in the chain. The potential distribution starts to develop a pattern after a certain number of insulators in the chain while the pollution induces high value spikes in the field distribution. Finite-element-analysis for numerical simulation of the pollution effect in outdoor insulators: a review and a novel method.
EN
This paper proposes training an artificial neural network (ANN) by a particle swarm optimization (PSO) technique to predict the flashover voltage of outdoor insulators. The analysis follows a series of real-world tests on high-voltage insulators to form a database for implementing artificial intelligence concepts. These tests are performed in various degrees of artificial contamination (distilled brine). Each contamination level shows the amount of contamination in milliliters per area of the isolator. The acquisition database provides values of flashover voltage corresponding to their electrical conductivity in each isolation zone and different degrees of artificial contamination. The results show that ANN trained by PSO can not only provide better prediction results, but also reduce the amount of computation efforts. It is also a more powerful model because: it does not get stuck in a local optimum. In addition, it also has the advantages of simple logic, simple implementation, and underlying intelligence. Compared to the results obtained by practical tests, the results obtained present that the PSO-ANN technique is very effective to predict flashover of high-voltage polluted insulators.
EN
Investigations of the flow in a building system are crucial for understanding the fundamental basis of the aerodynamic structure characteristics. The CFD simulations were conducted using ANSYS Fluent 17.0 software, which solves the Navier-Stokes equations in conjunction with different turbulence models and by a finite volume discretization method. Particularly, a comparison between the experimental and standard k-ω, BSL k-ω, SST k-ω, standard k-ɛ, RNG k-ɛ and Realizable k-ɛ turbulence model has been developed. The comparison between the founded results affirms that the standard k-ω turbulence model is the most efficient to model the air flow in the present application. Indeed, the numerical results compared using the experimental data developed in the LASEM laboratory confirms the validity of the numerical method. The good agreements validate the considered computational method.
EN
The flashover of pollution, observed on the insulators used in high voltage transmission, is one of the most important power transmission stakes. It is a very complex problem due to several factors including the modelling difficulties of complex shapes of insulators, different pollution densities at different regions, non-homogeneous pollution distribution on the insulator surface and unknown effect of humidity on the pollution. In the literature, some static and dynamic models have been developed by making some assumptions and omissions to predict the flashover voltages of polluted insulators. This paper aims to experimentally analyse the flashover process and simulation of the distributions of the potential and the electric field under 50 Hz applied voltage on a real model simulating the 175CTV outdoor insulators largely used by the Algerian Company of Electricity and Gas (SONELGAZ). This real model is studied under non-polluted (distilled water), and polluted (distilled water and sand) environments. The simulations were carried out by using the COMSOL multiphysics software. This program uses the finite element method to solve the partial differential equations that describe the field. Experimental results made in the laboratory and simulation results are original and found to be congruent.
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