Communications - Scientific Letters of the University of Zilina, 2013 (vol. 15), issue 3
Articles
Operation Analysis of Soft Switching PWM DC-DC Converter with Secondary Snubber
Jaroslav Dudrik, Marcel Bodor, Daniel Trip Nistor
Communications - Scientific Letters of the University of Zilina 2013, 15(3):6-12 | DOI: 10.26552/com.C.2013.3.6-12 
The paper deals with analysis of operation of a soft switching PWM DC-DC full-bridge converter with new energy recovery turn-off snubber on secondary side of high frequency power transformer.Principal equations are derived for individual operation states. On the basis of them the diagrams are made out. The diagrams give complex image on the converter behaviour during whole period of operation at nominal load. Theoretical waveforms are compared with simulation results.
Analysis of a Possible Battery Chargertopology
Yvonne Flicker, Felix A. Himmelstoss
Communications - Scientific Letters of the University of Zilina 2013, 15(3):13-20 | DOI: 10.26552/com.C.2013.3.13-20
Battery chargers are very important, especially for handhelds and cars. In this paper a converter is analyzed which enables us to control the voltage across the battery for a high input voltage range. Using the converter as a battery charger, the load current has to be controlled. Consequently, a two-point controller can be used. Therefore, a draft of a two-point controller is given. In addition, the weighted state differential equations are linearized in order to use the possibilities of the linear control theory. A basic analysis of the charger topology is given, the losses are approximated, and some experimental results are presented.
Bidirectional Step-Up/Step-Down DC-DC Converter with Magnetically Coupled Coils
Michal Frivaldsky, Branislav Dobrucky, Giacomo Scelba, Pavol Spanik, Peter Drgona
Communications - Scientific Letters of the University of Zilina 2013, 15(3):21-25 | DOI: 10.26552/com.C.2013.3.21-25
The paper is focused on bidirectional up/down DC-DC converter with magnetically coupled coils (MCC), which can be utilized as a part of power semiconductor system in traction, automotive, or industrial applications like renewable energy sources. Proposed solution of main circuit of bidirectional converter should serve for energy transfer from source to load, and vice versa, whereby parameters of electrical variables like voltage, current and power are able to be adapted based on the current requirements of application. Their values can be increased or decreased in first (energy transfer from source to load) or in third (energy transfer from load to...
Simulation Studies of the Underground DC Traction Substation with and without Energy Storage Device
Elzbieta Szychta, Grzegorz Krawczyk, Jozef Buday, Jozef Kuchta, Jan Michalik
Communications - Scientific Letters of the University of Zilina 2013, 15(3):26-31 | DOI: 10.26552/com.C.2013.3.26-31
This paper presents the results of the underground DC traction substation simulation studies for two versions: the substation equipped with the ESD (Energy Storage Device) and without the ESD. In these studies Supercapacitors Energy Storage System of energy capacity 10 kWh and voltage 900 V is used. Simulation studies were performed in the Simscape/Simulink.
Effective Utilization of Photovoltaic Energy Using Multiphase Boost Converter in Comparison with Single Phase Boost Converter
Jan Perdulak, Dobroslav Kovac, Irena Kovacova, Matus Ocilka, Andrii Gladyr, Dmytro Mamchur, Iurii Zachepa, Tibor Vince, Jan Molnar
Communications - Scientific Letters of the University of Zilina 2013, 15(3):32-38 | DOI: 10.26552/com.C.2013.3.32-38
The paper presents a novel concept of multiphase boost converter (MPBC) with high efficiency of energy conversion. The new topology of MPBC is compared with conventional single-phase boost converter (SPBC). It is shown that almost whole input energy from photovoltaic module entering to the proposed MPBC is utilized more effectively in comparison with conventional SPBC. This effective energy utilization is ensured by suitable algorithm of switches control. Modeling, simulation and experimental results are given. Subsequently the laboratory models of SPBC and MPBC were built and experimental results were obtained to confirm the simulation results. Also...
Implementation of Three Phase-Discontinuous Space Vector Modulation Using Single DSC-PWM Module
Stepan Janous, Jozef Sedlak, Michal Prazenica, Jozef Kuchta
Communications - Scientific Letters of the University of Zilina 2013, 15(3):39-42 | DOI: 10.26552/com.C.2013.3.39-42
The paper presents an implementation of a discontinuous space vector modulation of three phase inverter. The modulation is implemented in a DSC (Digital Signal Controller) using only one PWM module. Phases of the inverter work in a complementary mode. This implementation gives an assumption to use one DSC for simultaneous controlling of several three phase inverters. Furthermore, a simulation comparison of discontinuous and continuous space vector modulation is made.
Modelling of Power Converters Using Z-Transform
Branislav Dobrucky, Michal Pokorny, Mariana Benova, Mahmud Ali Rzig Abdalmula
Communications - Scientific Letters of the University of Zilina 2013, 15(3):43-47 | DOI: 10.26552/com.C.2013.3.43-47
The paper introduces a novel method of analysis and modelling of power electronic converters. Z-transform, numerical series (sequences) are used for both steady and transient states investigation of converters. The new impulse switching functions are created which are used as exciting functions of one- and multidimensional state-space models. Theoretical waveforms are compared with simulation results.
Fractal-Based Image Encoding and Compression Techniques
Vasileios Drakopoulos
Communications - Scientific Letters of the University of Zilina 2013, 15(3):48-55 | DOI: 10.26552/com.C.2013.3.48-55
In computer science and information theory, data compression, source coding, or bit-rate reduction is the process of encoding digital information using fewer bits than the original representation. Specifically, digital-image compression is important due to the high storage and transmission requirements. Various compression methods have been proposed using different techniques to achieve high compression ratios. Fractal image encoding is a technique based on the representation of an image by contractive transformations. Fractal-based image compression methods belong to different categories according to the different theories they are based on. In this...
Serial Resonant Converter and Load Coil for High Frequency Heating
Matus Ocilka, Dobroslav Kovac, Irena Kovacova, Jan Perdulak, Andrii Gladyr, Dmytro Mamchur, Iurii Zachepa, Tibor Vince, Jan Molnar
Communications - Scientific Letters of the University of Zilina 2013, 15(3):56-62 | DOI: 10.26552/com.C.2013.3.56-62
The paper deals with the design of the voltage source half-bridge resonant inverter with the specific load coil, which is suitable for induction heating applications. To ensure the correct functionality and right frequency range of the self-resonant converter, the parameters as inductance, self-capacitance and resistance of the coil have to be obtained. Parameters of the coil are estimated by utilizing software that uses finite elements method of solution. In order to estimate the accuracy of model, the experimental verifications were taken. For this purpose, the spiral coil made on printed circuit board was created and its parameters were calculated,...
Two-Phase Two-Stage HF Matrix Converter for Supplying Two-Phase Motor Load
Michal Prazenica, Michal Kabasta, Slavomir Kascak, Juraj Koscelnik, Jozef Buday
Communications - Scientific Letters of the University of Zilina 2013, 15(3):63-67 | DOI: 10.26552/com.C.2013.3.63-67
This paper deals with the two-stage two-phase electronic systems with orthogonal output voltages and currents - DC/HF_AC/2AC. It also introduces the design and prototype of two-stage DC/HF_AC/2AC high frequency converter with two-phase orthogonal output using two singlephase matrix converters in full-bridge connection operated with the unipolar PWM. Simulation and experimental results of matrix converter for both steady and transient states for IM motors are given in the paper together with experimental verification under R-L load. The results confirm a very good time-waveform of the phase current and the system seems to be suitable for low-cost application...
An Adaptive Neurocontroller for Induction Motors
Peter Girovsky, Jaroslava Zilkova, Jaroslav Timko, Jan Girovsky
Communications - Scientific Letters of the University of Zilina 2013, 15(3):68-72 | DOI: 10.26552/com.C.2013.3.68-72
The paper is focused on presenting possibilities of applying artificial neural networks (ANN) at creating a speed controller of an induction motor drive. The presented method of control takes advantage of approximating properties of multi-layer feedforward networks. The availability of the proposed neurocontroller is verified through the Matlab simulation. The effectiveness of the controller is demonstrated for different operating conditions and motor parameter changes of the drive system.
Using Fourier Analysis for Torque Estimation of Two-Phase Induction Motor Supplied by Halfbridge Inverter with PWM Control
Pavel Zaskalicky, Ludek Schreier
Communications - Scientific Letters of the University of Zilina 2013, 15(3):73-78 | DOI: 10.26552/com.C.2013.3.73-78
The paper deals with the steady state analysis of electromagnetic torque ripples of a two-phase induction machine, which is supplied by a half-bridge connected inverter with IGBT transistors. The inverter output voltage is controlled by a PWM of the input DC voltage. The complex Fourier series analysis of the inverter output voltage was made to obtain the spectrum of voltage-supply harmonics. Particular voltage harmonics were applied to the two-phase induction machine numerical model so that the electromagnetic torque waveforms for various operation conditions were obtained.
Analyses of the Causes of Common Rail Piezoelectric and Electromagnetic Injectors' Premature Destruction in Self-Ignition Engines
Slawomir Olszowski, Jozef Buday, Jozef Kuchta, Jan Michalik
Communications - Scientific Letters of the University of Zilina 2013, 15(3):79-82 | DOI: 10.26552/com.C.2013.3.79-82
In self-ignition engines with Common Rail direct fuel injection, premature destruction of injectors has been observed. New elements are also touched by the problem. In order to solve it, a group of international experts in the area have gathered. Destroyed piezoelectric and electromagnetic injectors' elements of BOSCH, DELPHI, DENSO, have been examined. Mechanical damages influencing electronic diagnostic signal have been presented. Some system solutions possible to perform as far as diagnostic prevention is concerned have been described. Some useful electronic diagnostic methods of fuel system, signal analysers: RMOG and ERDIA PRO, have been presented.
Complex Automated Information System for Remote Management of Crisis Situations in Rail Transport
Zdenek Dvorak, Maria Luskova, Petr Hruza, Radovan Sousek
Communications - Scientific Letters of the University of Zilina 2013, 15(3):83-88 | DOI: 10.26552/com.C.2013.3.83-88
The paper deals with topical information from the area of crisis information support. The contributing authors work at three co-operating universities where the subject of transport support in crises is tackled. At present the electronic support of crisis management in transport is necessary prerequisite for the functioning of transport system under both common and emergency situations. The outcomes of scientific research projects are new even from a broader European perspective. The preparation of complex automated information system for remote management of crisis situations in rail transport is new and has not been published yet. The outcomes of...
Comments on the Power of Kolmogorov Test
Andrzej Rogowski
Communications - Scientific Letters of the University of Zilina 2013, 15(3):89-95 | DOI: 10.26552/com.C.2013.3.89-95
This paper presents the results of estimating the power of Kolmogorov test and its modifications for testing hypothesis about an exponential distribution against the alternative hypothesis (population has a Weibull distribution). The power of test was calculated based on a distribution of empirical cumulative distribution function and limiting distribution, as well as computer-simulation methods. Some important properties and limitations were given that are related to power simulation study of goodness-of-fit tests.
Contributory Assessment of Creation of PM10 AS Impacted by Vehicular Traffic Based on the Presence of Heavy Metals
Dusan Jandacka
Communications - Scientific Letters of the University of Zilina 2013, 15(3):96-101 | DOI: 10.26552/com.C.2013.3.96-101
Emissions from different sources create a very complex mixture in the air both in qualitative and quantitative terms. Their composition is the result of distribution of all the sources in space and time, their size and characteristics of the pollutants on one side, and meteorological and climatic conditions on the other. Department of Highway Engineering of the Faculty of Civil Engineering at the University of Zilina has taken part in the project that focuses on the monitoring of dust particles formation initiated by road transport depending on both the road surface and traffic intensity, load. During the project the monitoring was focused on the measurement...
Life-Cycle Cost Analysis in Pavement Management System
Jan Mikolaj, Frantisek Schlosser, Lubos Remek
Communications - Scientific Letters of the University of Zilina 2013, 15(3):102-106 | DOI: 10.26552/com.C.2013.3.102-106
Pavement Management System (PMS) is a set of methods and tools which allow for optimal allocation of limited resources while keeping the road network in serviceable condition. The system evaluates the viability of all maintenance, rehabilitation and reconstruction (MR&R) actions; the evaluation is a comparison process between procurement cost of MR&R action and benefits, which are achieved by the new, more favourable, serviceability conditions attained as a result of this particular action. The investment cost - procurement costs of MR&R action - are evaluated in terms of economical effectiveness by means of Life-Cycle Cost Analysis (LCCA).
Behaviour and Strength of Headed Shear Stud Connectors
Patricia Duratna, Jan Bujnak, Abdelhamid Bouchair, Frantisek Bahleda
Communications - Scientific Letters of the University of Zilina 2013, 15(3):107-111 | DOI: 10.26552/com.C.2013.3.107-111
Headed stud shear connectors are commonly used to transfer longitudinal shear forces across the steel-concrete interface in composite structures. This paper is focused on the experimental and numerical study on the behaviour of this type of connectors. The push-out tests of headed studs, 10 mm in diameter and 50 mm in length, in normal C25/30 concrete with transverse reinforcement were carried out. The experimental study also treated the influence of the connectors spacing, in the longitudinal and transversal directions, and the thickness of the concrete slab on the shear resistance.
Numerical Analysis of the Bridge Orthotropic Deck Time Dependent Resistance
Josef Vican, Marian Sykora
Communications - Scientific Letters of the University of Zilina 2013, 15(3):112-117 | DOI: 10.26552/com.C.2013.3.112-117
Resistance of the stiffened plated orthotropic deck of bridge with ballast bed is affected by the environmental action effects due to unchecked corrosion process of steel bridge deck under ballast bed. Therefore, to observe the behaviour and resistance of those types of steel bridges, the probabilistic nonlinear finite element analysis using adequate sophisticated software is needed. The paper presents results of the parametric numerical analysis of the time dependent resistance of bridge with ballast bed on the orthotropic deck considering corrosion attack using ANSYS software support module PDS. Random variables entering calculations were described...
Use of Video Analysis of Conflict Situations for Monitoring the Traffic on Urban Road Influenced by Parallel Parking
Vladislav Krivda, Ivana Mahdalova, Jan Petru
Communications - Scientific Letters of the University of Zilina 2013, 15(3):118-125 | DOI: 10.26552/com.C.2013.3.118-125
The paper deals with problems of influence of parallel parking on urban roads for road traffic safety. It shortly refers to evaluation of normative principles related to parking of road vehicles in the Czech Republic.It presents the results of analysis of traffic participant behavior on the particular section of inhabited area by use of video analysis of conflict situations. Thus it is pointed out to a possibility of application of this methodology in execution of safety inspections on roads, for example.
Wheel/Rail Contact Stress Evaluation by Means of The modified Strip Method
Tomas Lack, Juraj Gerlici
Communications - Scientific Letters of the University of Zilina 2013, 15(3):126-132 | DOI: 10.26552/com.C.2013.3.126-132
The Strip Method is often used for rail/wheel contact area and contact normal stress evaluation. The paper deals with the computational time saving procedure when the computation accuracy is guaranteed. We included the local coordinate system with a presupposed semi-circular course of the normal stress for the purpose of the integral that is necessary for deformation in the middle of individual strips evaluation. The integral is solvable analytically. The input parameters for individual parts of splines and individual strips expression are possible to insert after analytical solution.