Wyniki wyszukiwania - BazTech

1

Reliability and Availability Analysis of Transport System Composed of Dependent Subsystems

Dziula Przemysław

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

|

2025

|

Vol. 19 No. 1

187--195

EN

The paper presents reliability and availability analysis of the transport system, taking into account its structure, that is composed of dependent subsystems. The issues introduced are basing on the assumption that one subsystem impacts on functioning of other subsystems, meaning - disruptions occurring within the subsystem can reduce functionality and change level of safety and inoperability of others. By means of multistate approach to analysis, it has been assumed that the deterioration of one subsystem affects the reliability of other subsystems and the entire system. Following this assumption, the transport system reliability function and its basic reliability characteristics were determined. In addition, the system availability function was set out, assuming that its renewal is carried out when its reliability falls below a certain threshold. Furthermore, the reliability and availability analysis of the transport system were conducted, taking into account additional stress on its particular subsystem at certain time points. The summary contains conclusions resulting from the analysis and comparison for various additional stress levels.

2

Dependence of the Maximum Approach Distance on the Shape of the Ship's Safe Domain

Burmaka Igor, Zhukov Dmytro

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

|

2025

|

Vol. 19 No. 1

265--268

EN

In work analytical expressions are resulted for a calculation minimum - possible distance of rapprochement in the case of application of domains of elliptic and difficult form. Shown graphic dependence minimum - possible distance of rapprochement from foreshortening of ships which are drawn together, for the domains of both types. It is shown that the domains of elliptic and difficult form have a similar character of change minimum - possible distance of rapprochement depending on foreshortening of ships.

3

Model matematyczny nieliniowego obwodu elektromagnetycznych o parametrach skupionych na podstawie zmodyfikowanej zasady Hamiltona-Ostrogradskiego

Chaban Andriy, Szafraniec Anna, Levoniuk Vitaliy, Erd Andrzej, Chmiel Marek

Przegląd Elektrotechniczny

|

2025

|

R. 101, nr 2

32--35

PL

W pracy, na podstawie zmodyfikowanej zasady Hamiltona-Ostrogradskiego, opracowano model matematyczny typowego obwodu elektromagnetycznego o parametrach skupionych, który wykorzystuje koncepcję mechanicznego i elektrycznego formalizmu Lgrange’a. W tym celu został opracowany niekonserwatywny lagrangian, który oprócz tradycyjnych funkcji energii kinetycznej i potencjalnej zawiera energie sił rozproszenia oraz sil niepotencjalnych. Równania obwodów elektromagnetycznych otrzymano w postaci macierzowo-wektorowej. Przedstawiono wyniki symulacji komputerowej w postaci rysunków, które są analizowane.

EN

A mathematical model of a typical concentrated parameter electromagnetic circuit using the concept of the mechanical and electric Lagrange’s formalism is developed on the basis of the modified Hamilton-Ostrogradsky principle. To this end, a non-conservative lagrangian is compiled including, beside the traditional functions of kinetic and potential energy, the energies of dissipation and non-potential forces. The electromagnetic circuit equations are prepared in the matrix-vectoral form. Computer simulation results are presented graphically and analysed.

4

Mathematical modeling of transient processes in a section of open-phase power grid

Chaban Andriy, Szafraniec Andrzej, Levoniuk Vitaliy, Lewiński Andrzej, Chmiel Marek

Przegląd Elektrotechniczny

|

2025

|

R. 101, nr 3

32--35

EN

Relying on the fundamental laws of applied electric engineering, a mathematical model is developed of a power grid section that consists of a supply line and a three-phase power transformer. The line is represented as a resistance-induction-volume element supplied from an asymmetrical electromotive force (EMF) system source, the transformer as non-linear electromagnetic circuits. This model serves the purpose of analysing the object’s transient states, including its open-phase state.

PL

W pracy niniejszej wychodząc z podstawach praw elektrotechniki stosowanej opracowano model matematyczny fragmentu sieci elektroenergetycznej, który składa się z linii zasilania oraz trójfazowego transformatora mocy. Linia przedstawiona jest, jako rezystancyjnoindukcyjno-pojemnościowy element, zasilany przez źródło asymetrycznego układu sił elektromotorycznych SEM. Transformator mocy przedstawiony jest, jako nieliniowy element w postaci elektromagnetycznych obwodów. Za pomocą tego modelu analizowane są stany przejściowe układu, w tym stan niepełnofazowy.

5

Design and Application of Marine Robotics with a Communication Buoy

Blintsov Volodymyr S., Babkin Heorhii V., Kostenko Dmytro V., Moroz Volodymyr, Korobov Vitalii, Tarchuk Andrii

Polish Maritime Research

|

2025

|

nr 4

142--149

EN

The basic principles of construction for a towed buoy with a arc-shaped wing are formulated and substantiated in this paper. The main characteristics of a load-bearing wing in an arched configuration are calculated, and the main dependencies and design features of the arched wing are proposed. A mathematical 3D model is built, and its hydrodynamic characteristics are mathematically modelled in the ANSYS software environment. Experimental investigations of a half-model of an arched wing are conducted in a hydrodynamic tunnel. The model is created by 3D printing, with a Clark-Y chord profile and a tapered wingspan. The wing model is curved in an arc with a radius of 210 mm, covering a 90° sector, and is tested using a special experimental setup in a hydrodynamic tunnel in order to study the hydrodynamic characteristics of oscillating wings. This special experimental setup consists of two main blocks: a two-component strain gauge platform, and an electromechanical drive that provides the harmonic angular oscillations of the wing suspension assembly. The dependencies of the lift and drag coefficients on the angle of attack are determined experimentally. After thorough verification and calibration of the experimental setup, repeated tests are conducted on two geometrically similar wing models. This work was conducted at the Underwater Technology Research Institute of Admiral Makarov National University of Shipbuilding and the Institute of Hydromechanics of the National Academy of Sciences of Ukraine, as part of the development of modern underwater technology prototypes. The results will be integrated into the curricula of the Admiral Makarov National Shipbuilding University.

6

Heavy metals distribution in water and soil of the coastal zone of the Styr River (Ukraine) and its tributaries

Skrobala Victor, Popovych Vasyl, Kopylov Victor, Kopystynskyi Yurii

Journal of Ecological Engineering

|

2025

|

Vol. 26, nr 2

1--14

EN

Investigation of the peculiarities of chemical contamination of water and soil in the coastal zone of the river Styr and its tributaries in relation to the distance from the source of pollution and the type of landscape, analysis of the general trends in the distribution of chemical elements in comparison with the control site. Statistical processing of parameters of chemical contamination of water and soil; data mining methods; correlation analysis; assessment of ecotope similarity and grouping of chemical elements based on cluster analysis; multidimensional ordination of ecotopes in the space of geochemical parameters based on Principal Component Analysis. Chemical contamination of water and soil in the coastal zone of the Styr River and its tributaries is characterised by significant heterogeneity. The main feature of the increasing intensity of anthropogenic load on the aquatic environment is associated with an increase of Cu, Zn, Pb, Mn content compared to the natural background. The intensity of soil pollution in the coastal zone of the Styr River and its tributaries mainly depends on the presence of Cu, Cd and Ni. The analysis of the relationship between chemical elements concentrations indicates a strong dependence between many parameters. Based on the similarity of chemical elements in terms of their distribution in the water of the river Styr and its tributaries, 4 associations (groups) were identified: I – Cu, Mn; II – Zn, Pb; III – Cd, Cr, Sr; IV – Co, Ni. For the soils in the coastal zone, 3 associations (groups) of chemical elements were identified: I – Cu, Cd; II – Zn, Mn; III – Cr, Co, Ni, Pb. Three groups of sites of the Styr River and its tributaries were identified according to the pollution rate of water and soils of the coastal zone with heavy metals. The multidimensional ordination of the ecotopes of the Styr River and its tributaries on the axes of complex geochemical environmental gradients reflects the gradients of water and soil pollution in the coastal zone compared to the control areas. Geochemical information visualisation based on two-dimensional diagrams with chemical element concentrations or complex environmental gradients as axes can be used to predict the dynamics of ecosystem components as a result of changes in chemical pollution. The practical relevance of the obtained results is that forecasting of dynamic trends, protection and restoration of ecosystem components is impossible without taking into account their interrelationships with environmental conditions, including chemical pollution. Knowing the geochemical conditions of ecotopes in a certain period of time, it is possible to determine their position in the ecological space on the complex gradients of the environment of the Styr river and its tributaries, to predict the stability and possible changes in vegetation, fauna and microflora caused by environmental pollution.

7

Design of multidimensional nonlinear predictive controller for 3D crane

Szafrański Maciej, Piotrowski Robert

Journal of Automation Mobile Robotics and Intelligent Systems

|

2025

|

Vol. 19, No. 2

41--49

EN

This paper presents a comprehensive approach to design and implementation of a multidimensional nonlinear control system for a 3D crane. For design purposes, a simulation model of the crane is developed and verified. Proposed are two structures of the control system, which are based on a PID controller and predictive control system. The synthesis process is presented. The designed systems are verified in terms of their effectiveness based on the judgement on the obtained waveforms of controlled variables and integral control indicators. Finally, the two systems are compared with each other, and the conclusions regarding their applicability for this type of system are presented.

8

A Stochastic Petri Net-Based Model of Non-Enzymatic RNA Degradation

Rybarczyk Agnieszka

Scientific Journal of Gdynia Maritime University

|

2024

|

nr 131

7--22

EN

In recent years, RNA research has grown due to the discovery of its important role in biological systems. RNA molecules are involved in protein synthesis and play a critical role in gene expression. Many of these molecules are produced through the enzymatic digestion or spontaneous degradation of larger molecules, and are consequently essential for cellular processes. The mechanisms of RNA degradation appear to be one of the most important factors influencing RNA activity. In this study, a stochastic Petri net-based model of spontaneous (non-enzymatic) RNA degradation was built and analysed. The model was analysed using t-invariants, MCT sets, and simulation-based analyses. The systems approach enabled a thorough analysis of the phenomenon, resulting in significant biological insights.

9

Heat Transfer Through a Three-chamber Glass Unit

Basok Borys, Davydenko Borys, Pavlenko Anatoliy, Goncharuk Svitlana, Koshlak Hanna, Lysenko Oksana

Rocznik Ochrona Środowiska

|

2024

|

Tom 26

49--55

EN

A well-known way to increase the thermal insulation properties of windows in buildings is to increase the number of glasses in a window or, what is the same, to increase the number of glass chambers in a glass unit. This method, in combination with low-emissivity coatings on the inner surfaces of glass, can provide a significant increase in the heat transfer resistance of window structures. The use of such windows in construction can significantly reduce heat loss from the premises in the winter, which leads to a reduction in energy costs for heating and increases the energy efficiency of the building. In this work, the characteristics of heat transfer through a three-chamber glass unit are studied using numerical modeling and experimental study. Options for the absence and presence of low-emissivity coatings on glass are considered. Changes in air velocity and temperature in the chambers are studied. Heat transfer resistance for three-chamber windows are calculated depending on the number of low-emissivity coatings on the glass.

10

Mathematical modelling of transient processes in a HVAC transmission line considering the effect lightning protection cables in the state of two-phase short-circuiting

Chaban Andriy, Lis Marek, Szafraniec Andrzej, Levoniuk Vitaliy

Przegląd Elektrotechniczny

|

2024

|

R. 100, nr 3

278--281

EN

A mathematical model is developed of a fragment of an electric power transmission system whose key part is a long ultra-high voltage power line including lightning protection cables of distributed parameters. The model is based on a long line second-order partial derivative equation. The boundary conditions of the second and third types (Neuman and Poincare conditions) are used for the purposes of the equation. The line equations are solved by discretising partial derivatives using the straight-line method and then integrating the latter with the fourth-order Runge-Kutta method. Simulation results are given in a graphic format analysed in the state of two-phase short-circuiting.

PL

W artykule opracowano model matematyczny systemu przesyłania energii, którego elementem kluczowym jest długa linia elektroenergetyczna wysokiego napięcia z przewodami odgromowymi, analizowana, jako układ o parametrach rozłożonych. Opracowany model matematyczny opiera się na równaniu długiej linii drugiego rzędu o pochodnych cząstkowych. Do równania linii długiej wykorzystano warunki brzegowe drugiego i trzeciego rodzaju: Neumana i Poincarego. Równania linii rozwiązano drogą dyskretyzacji pochodnych cząstkowych metodą prostych z kolejnym całkowaniem w funkcji czasu za pomocą metody Runge-Kutty czwartego rządu. Wyniki symulacji podane są w formie rysunków, które są analizowane w stanie zwarcia dwufazowego.

11

Analiza potencjału wytwarzania energii elektrycznej w instalacji komina słonecznego z nachylonym kolektorem słonecznym

Berdowska Sylwia

Przegląd Elektrotechniczny

|

2024

|

R. 100, nr 2

78--83

PL

W pracy zaprezentowano analizę parametrów pracy komina słonecznego z kolektorem położonym pod kątem 30˚, 45˚, 60˚ i 90˚. Obliczenia przeprowadzono dla kolektora usytuowanego w ośmiu kierunkach geograficznych. Analizę wykonano dla warunków klimatycznych panujących w Katowicach. W pracy przedstawiono skumulowaną ilość energii elektrycznej, którą można uzyskać w poszczególnych miesiącach roku. Dokonano porównania wytwarzania energii elektrycznej w instalacji z pochylonym kolektorem dla poszczególnych kierunków geograficznych oraz instalacji z poziomym kolektorem słonecznym. Instalacja z kolektorem położonym pod kątem 60˚ w kierunku południowym pozwala na wytworzenie największej ilości energii elektrycznej.

EN

The paper presents an analysis of the parameters of the solar chimney with a collector located at the angle of 30˚, 45˚, 60˚ and 90˚. The calculations were carried out for the collector oriented in eight geographical directions. The analysis was performed for the climatic conditions in Katowice. The work presents the cumulative amount of electricity that can be obtained in each month of the year. A comparison of electricity generation in an installation with an inclined collector for particular geographical directions and an installation with a horizontal solar collector was made. Installation with the collector located at 60˚ to the south allows for the generation of the largest amount of electricity.

12

Analiza parametrów pracy komina słonecznego z nachylonym kolektorem słonecznym

Berdowska Sylwia

Przegląd Elektrotechniczny

|

2024

|

R. 100, nr 8

219--224

PL

W artykule przedstawiono badania głównych parametrów pracy instalacji komina słonecznego z kolektorem nachylonym pod kątem 30˚, 45˚, 60˚ oraz 90˚. Analizę wykonano dla kolektora słonecznego usytuowanego w czterech głównych oraz czterech pośrednich kierunkach geograficznych. Badania przeprowadzono dla całego roku pracy instalacji w warunkach klimatycznych panujących w Katowicach. W pracy dokonano porównania takich parametrów jak przyrost temperatury powietrza oraz jego prędkość w układzie komina słonecznego z pochylonym kolektorem dla poszczególnych kierunków geograficznych. Najlepsze parametry pracy instalacji można uzyskać dla kolektora zorientowanego w kierunkach: południowym, południowo-wschodnim, południowo-zachodnim.

EN

The paper presents research of the main operating parameters of a solar chimney installation with a collector inclined at the angle of 30˚, 45˚, 60˚ and 90˚. The analysis was performed for a solar collector located in four main and four intermediate geographical directions. The analysis were carried out for the entire year of installation operation in the climatic conditions in Katowice. The work compares parameters such as the increase of air temperature and air speed in the sloped solar chimney system for the individual geographical directions. The best operating parameters of the installation can be obtained with the collector oriented in the following directions: south, south-east, south-west.

13

Elaboration of Simulation Complex for Realization of Adaptive Neural Flight Control System to be used on Commercial Aircraft in Compliance with EASA-FAA Standards

Prosvirin Dmytro, Pawęska Marcin, Kharchenko Volodymyr

Logistics and Transport

|

2024

|

Vol. 61-62, No. 1-2

105--113

EN

In this paper, the typical scheme of the adaptive neuron technology of automatic control systems (ACS) of aircraft, which is adhered to by all the main developers of control systems, is considered. The theoretical justification of the current tendencies of reducing the volume of flight tests by increasing the volume of mathematical modelling and bench testing has been given.

14

Mathematical modelling of gas nitriding process of steel using cellular automata

Ratajski J., Mydłowska K.

Journal of Achievements in Materials and Manufacturing Engineering

|

2024

|

Vol. 126, nr 2

58--65

EN

Purpose: The primary aim of this research was to develop a mathematical and computational model of the nitriding process for steel using CA cellular automata theory, which enables the modelling of spatial hardness distributions and nitrogen concentrations within the material. Design/methodology/approach: The proposed mathematical model consists of two interacting cellular automata: one representing the surface layer of the nitride material and the other describing the spatial distribution of nitrogen. The developed algorithm and model based on CA were implemented in the MATLAB environment, enabling more effective and efficient testing of the created model and its further use. Findings: The developed computer model enabled, by changing the values of the CA model parameters, which correspond to the nitrogen diffusion coefficient in alloy steel, nitrogen solubility in iron and the enthalpy of formation and decomposition of iron nitrides, to adapt the model to the description of the nitriding process of 1.2343 (WCL) steel. The model was experimentally verified by comparing predicted hardness profiles with those measured after nitriding. Research limitations/implications: The main limitation of the developed model is the size of the material fragment in which the nitriding process is simulated. Practical implications: High compliance of the results of numerical calculations with the results obtained by experimental measurements was obtained, which predestines the potential usage of CA-based models for scientific and practical applications. The model can be used as part of an optimisation procedure for designing hybrid composite layers for tribological applications, comprising a nitride layer and a coating deposited via Physical Vapor Deposition (PVD) techniques. Originality/value: The added value of the developed model of the nitriding process, based on the concept of CA, is the author’s modification of the transition rules (both for cells in the Moore and von Neumann neighbourhood) in the automaton related to the structural and phase transformations in the nitride material.

15

Development of Soft Computing-based Predictive Tools for Estimating the Young Modulus of Weak Rocks

Köken Ekin, Strzałkowski Paweł

Civil and Environmental Engineering Reports

|

2024

|

Vol. 34, no. 3

182--193

EN

The deformation characteristics of rocks are of vital importance in addressing most geomechanical issues as they are one of the most critical input parameters in rock engineering analyses. For this reason, robust forecasting models are required when analysing the stability of tunnels, slopes, mine galleries, and other underground excavations. In this research, novel predictive models are proposed to estimate the tangential Young modulus (Eti) of weak rocks. To achieve this, an extensive literature review is performed to obtain a comprehensive database including critical physico-mechanical properties of various weak rocks. Thanks to the advantages of soft computing methods such as genetic algorithm (GA), adaptive neuro-fuzzy inference system (ANFIS), artificial neural networks (ANN) and multivariate adaptive regression splines (MARS), novel predictive models are established. The effectiveness of the developed predictive models is investigated using various statistical measures and it is concluded that empirical models utilizing ANN and ANFIS methodologies are the most effective tools for estimating the Eti of weak rocks. In addition, a practical design chart is also developed for assessing the Eti of weak rocks.

16

Simplified mathematical model of oxy-fuel combustion of municipal solid waste in the grate furnace: effect of different flue gas recirculation rates and comparison with conventional mode

Copik Paulina, Szlęk Andrzej, Ditaranto Mario

Archives of Thermodynamics

|

2024

|

Vol. 45, no. 4

13--25

EN

Bioenergy carbon capture technology (BioCCS or BECCS) plays a key role in the European Green Deal, which aims to decarbonize industry and energy sectors, resulting in the production of energy with negative CO2 emissions. Due to the biogenic origin of carbon contained in municipal solid waste (MSW), the application of carbon capture in waste incineration plants can be classified as BioCCS. Thus, this technology has attracted scientists' attention recently since it reduces excessive waste and emissions of carbon dioxide. Currently, there are four incineration plants in the Netherlands, Norway and Japan, in which CO2 capture is implemented; however, they are based on the post-combustion technique since it is the most mature method and not requires many changes in the system. Nevertheless, the separation of CO2 from the flue gas flow, which contains mostly nitrogen, is complex and causes a large drop in the total performance of the system. Oxy-fuel combustion technology involves the replacement of air as an oxidizer into high purity oxygen and recirculated exhaust gas. As a result, CO2-rich gas is produced that is practically ready for capture. The main goal of the study is to develop a mathematical model of oxy-waste combustion to answer the research questions, such as how the composition of oxidant that is supplied to the process affects the combustion performance. The model includes all important processes taking place within the chamber, such as pyrolysis, char burnout and gas combustion over the grate. The results of the work will contribute to the development of oxy-waste incineration plants and will be useful for design purposes.

17

Numerical model for simulating the hydraulic parameters of the aeration system ensuring equal oxygenation of the compost hea

Sidełko Robert, Boruszko Dariusz

Archives of Environmental Protection

|

2024

|

Vol. 50, no. 1

87--94

EN

The aim of the work was to develop a mathematical model using equations of fluid mechanics that describe the dynamics of air flow in a part of the compost aerating system integrated with a stationary reactor. The results of the simulation show that adjusting the flow resistance along the entire length of the compost aerating duct, depending on the distance from the connection of the duct with the fan's pressure conduit pipe through gradually increasing the air outflow area by increasing the number of repeatable gaps, yields a uniform pressure distribution above the grate. The process parameters used for computation were relevant to composting a subscreen fraction separated from mixed municipal waste using 80 mm mesh screen (Fr<80 mm) under real conditions. Microsoft EXCEL 2010 software and STATISTICA version 13.3 by StatSoft were used for numerical and statistical analysis of the test results. The research results are presented in four tables and five figures and discussed in the text of the article. During tests performed in real conditions, various variants were tested for reactor filling level and air outflow active surfaces in subsequent grate parts (Fc (i)). It was found that the target waste layer thickness i.e. 3.0 m and Fc (i) changes, in accordance with the values of the developed model, result in a stable pressure distribution pd, amounting to 1506 Pa and 1495 Pa at the grate front and end part.

PL

. Celem pracy było opracowanie modelu matematycznego wykorzystującego równania mechaniki płynów, które opisują dynamikę przepływu powietrza w części instalacji napowietrzającej kompost zintegrowanej z reaktorem stacjonarnym. Wyniki przeprowadzonej symulacji pozwalają stwierdzić, że regulacja oporów przepływu na całej długości kanału napowietrzającego kompost w zależności od odległości od połączenia kanału z przewodem ciśnieniowym wentylatora poprzez stopniowe zwiększanie powierzchni wypływu powietrza poprzez zwiększanie liczby powtarzalnych szczelin, zapewnia równomierny rozkład ciśnienia nad rusztem. Parametry procesu przyjęte do celów obliczeniowych były odpowiednie dla kompostowania frakcji podsitowej w warunkach rzeczywistych wydzielonej ze zmieszanych odpadów komunalnych za pomocą sita o oczkach 80 mm (Fr<80 mm). Do analizy numerycznej i statystycznej wyników badań wykorzystano oprogramowanie Microsoft EXCEL 2010 firmy oraz STATISTICA firmy StatSoft w wersji 13.3. Wyniki badań przedstawiono w czterech tabelach i pięciu rysunkach oraz omówiono w tekście artykułu. Wyniki uzyskane w warunkach rzeczywistych wskazują, że opracowany model pozwala na prawidłowe zaprojektowanie perforacji kraty odpowiadającej za równomierne napowietrzenie kompostu. W trakcie badań przeprowadzonych w warunkach rzeczywistych, gdy badano różne warianty stopnia napełnienia reaktora i powierzchni czynnych wypływu powietrza w kolejnych częściach rusztu (Fc (i)) stwierdzono, że docelowa grubość warstwy odpadów tj. 3,0 m oraz zmiany Fc (i), zgodnie z wartościami opracowanego modelu, skutkują stabilnym rozkładem ciśnień pd wynoszącym 1506 Pa i 1495 Pa w części czołowej i końcowej kraty.

18

Modeling of the oscillatory motion of vehicle suspension elements during the loading of a trailer with bulk material

Kolodnenko Vitalii, Kalinin Yevhen, Savoiskyi Oleksandr, Solarov Oleksandr

Archives of Engineering Knowledge

|

2024

|

T. 10, Nr 1

158--164

EN

The paper presents a study of the oscillatory dynamics of a road train when loading a semi-trailer with bulk material (grain), in particular, during reloading from a combine harvester hopper. It is established that the peculiarities of the location of the flow of bulk material significantly affect the vertical oscillations of the suspension elements of the vehicle and trailer, which in turn affects the technical condition of the vehicle and driver comfort. Analytical and numerical modelling of the dynamic behaviour of a road train is carried out, taking into account the design characteristics of the suspension, tyres, damping elements, as well as the conditions of load transfer from the bulk medium. Three main load points were evaluated: over the trailer axle, over the vehicle axle, and between the axles. The smallest fluctuations, with a reduction of up to 45% compared to the other positions, are observed when loading between the bridges. The mathematical model takes into account the complex disturbing effects arising from impulse loading and allows determining the modes of impact: rectangular (up to 60 l/min), cosine (up to 100 l/min) and exponential (over 100 l/min). The results obtained can be used to optimise the design of suspensions, plan routes and develop recommendations for safe loading. The distribution of masses in real operating conditions was also taken into account, which ensures the practical significance of the work for the agro-transport industry.

19

Time-harmonic finite element model for brushless doubly-fed induction machine in natural operating mode

Jagieła Mariusz, Łukaniszyn Marian

Archives of Electrical Engineering

|

2024

|

Vol. 73, nr 3

615--628

EN

The natural mode of operation for the brushless doubly-fed induction machine is a particular instance of synchronism at a so-called natural rotor velocity when one stator winding is powered by an AC and the other by a DC voltage source. Consequently, in addition to the rotating magnetic field, there exists a magnetic field that is fixed to the stator frame of reference. Analysis in this specific mode is essential as the natural velocity arises from the choice of pole numbers, thereby determining machine efficiency. However, this presents a significant challenge when it comes to mathematical modeling using complex-valued steady-state models through either equivalent-circuit or finite element analysis. This paper presents a study on the extension of the recently-proposed steady-state complex-valued finite element model for the brushless doubly-fed induction machine to enable its application in the natural operating mode. A high correlation with the data obtained from a time-stepping model is obtained for the extended model when subjected to both low and high levels of saturation of the magnetic circuit. This extension makes the whole approach applicable in all operating conditions and modes of the brushless doubly-fed induction machine. Considering the nearly two orders of magnitude lower computational costs associated with analysis via the proposed model compared to time-stepping analysis, it is particularly useful in scenarios that involve extensive computations and require multiple cases to be considered such as design sensitivity analysis, topology optimization or a connection with machine learning techniques.

20

Selected static characteristics of a parallel active power filter with feedback from the supply voltage

Grugel Piotr, Mućko Jan

Archives of Electrical Engineering

|

2024

|

Vol. 73, nr 1

37--50

EN

The article presents selected static characteristics of a parallel active filter with voltage control in the supply line (VPAPF – Voltage-controlled Active Power Filter) as a function of parameters of the supply network. The tests were done on the basis of a simulation model of the supply network and an appropriate compensator. The test results showed that VPAPFs are most suitable for operation in weak networks, maintaining an almost constant level of voltage distortion, regardless of the value of the network impedance. In addition, the influence of the parameter G corresponding to the conductance value suppressing higher harmonics of the network voltage on the operation of the active power filter was determined.