ELEKTRYKA - Issue 1/2012 (221) - Politechnika Śląska, Wydział Elektryczny

ELEKTRYKA - Issue 1/2012 (221)

ELEKTRYKAYear LVIII (2012)

QuarterlyIssue 1 (221)

Scientific Committee

CONTENTS

Foreword

Marcin SOWA, Dariusz SPAŁEK: An electromagnetic field boundary value problem of a cylindrical structure with a nonlinear region – solution obtained by analytical-numerical method
Krzysztof BODZEK, Bogusław GRZESIK: Analysis of maximum power of linear concentric transformer at admissible temperature
Michał JELEŃ, Grzegorz JAREK, Jarosław MICHALAK, Kazimierz GIERLOTKA: Application of a 3-phase voltage inverter to supply of a DC motor from an AC grid
Marian HYLA, Andrzej KANDYBA: Non-surges switching of AC-AC voltage controller
Andrzej KANDYBA, Marian HYLA: Glidarc type plasmatron fed by AC voltage source converter – numerical analysis
Janusz WALCZAK, Seweryn MAZURKIEWICZ: Transformations of moments of harmonizable stochastic signals in deterministic nonlinear systems
Janusz WALCZAK, Seweryn MAZURKIEWICZ: Transformations of moments of stochastic signals in the random nonlinear systems
Grzegorz REDLARSKI: The assessment of the angular speed control system modification possibility in a steam turbine for the purpose of eliminating an automatic synchronizer
Piotr GAS: Influence of the coaxial-slot antenna's input power on temperature distribution during interstitial microwave hyperthermia

Marcin SOWA, Dariusz SPAŁEK

Instytut Elektrotechniki i Informatyki, Politechnika Śląska w Gliwicach

AN ELECTROMAGNETIC FIELD BOUNDARY VALUE PROBLEM OF A CYLINDRICAL STRUCTURE WITH A NONLINEAR REGION – SOLUTION OBTAINED BY ANALYTICAL-NUMERICAL METHOD

Summary. A nonlinear problem in the electromagnetic field theory is considered: a cylindrical structure with a nonlinear conductive layer placed in a uniform sinusoidal field. An attempt was made to determine the magnetic vector potential distribution for imposed boundary conditions of the first (Dirichlet boundary condition) and second (Neumann condition) kind. For this purpose, a method that bases on the “small parameter” expansion is used. A characteristic feature of the chosen method is that it includes the need for symbolic calculation. Furthermore, in order to verify the solution, differential equation errors were defined and evaluated (integral error and maximum error). Additionally, the power balance was verified. The aim of this paper is to present a method allowing obtainment of a model solution for chosen problems in the electromagnetic field theory which involve nonlinear conductivity.

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Krzysztof BODZEK, Bogusław GRZESIK

Katedra Energoelektroniki Napędu Elektrycznego i Robotyki, Politechnika Śląska w Gliwicach

ANALYSIS OF MAXIMUM POWER OF LINEAR CONCENTRIC TRANSFORMER AT ADMISSIBLE TEMPERATURE

Summary. The maximum power of a linear concentric transformer at the admissible temperature of 100°C is analyzed. The analysis is carried out by the proposed thermal FEM model that was verified by measurements. The measurements were experimentally verified using the National Instruments system and a thermocouple of K type. The power density of the investigated transformers is about 124 kV∙A/kg

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Michał JELEŃ, Grzegorz JAREK, Jarosław MICHALAK, Kazimierz GIERLOTKA

Katedra Energoelektroniki Napędu Elektrycznego i Robotyki, Politechnika Śląska w Gliwicach

APPLICATION OF A 3-PHASE VOLTAGE INVERTER TO SUPPLY A DC MOTOR FROM AN AC GRID

Summary. The alternative way of using the classical voltage inverter to supply a DC motor from an AC voltage source is presented in the paper. The converter ensures motor and generator operation of the machine, return of energy to the mains and quasi-sinusoidal waveforms of the line currents. The schematic diagram of connections, properties and idea of the control system are presented. The results of laboratory tests are given and compared with those for the thyristor rectifier-based system.

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Marian HYLA, Andrzej KANDYBA

Katedra Energoelektroniki Napędu Elektrycznego i Robotyki, Politechnika Śląska w Gliwicach

NON-SURGES SWITCHING OF AC-AC VOLTAGE CONTROLLER

Summary. In this paper there is presented a method for control of transistor switches in a single-phase and three-phase four wire AC–AC PWM voltage controller. In traditional switching control methods the dead times are introduced between transistor switching to avoid electrical shorts circuit. In operation with RL load this traditional switching control leads to switching surges caused by self-induction phenomena. Special surge arrester circuits are necessary to protect transistors. The proposed in this paper new switching control method allows eliminating dead times, hence commutation surges generated by RL load. This new switching control method also helps avoid short circuits.

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Andrzej KANDYBA, Marian HYLA

Katedra Energoelektroniki, Napędu Elektrycznego i Robotyki, Politechnika Śląska w Gliwicach

GLIDARC TYPE PLASMATRON FED BY AC VOLTAGE SOURCE CONVERTER – NUMERICAL ANALYSIS

Summary. In the paper there is described the structure of the energoelectronic power system model of a GlidArc plasmatron. There are presented the model components and some results of computer simulations. There are also given conclusions that support the process of practical implementation of such a system.

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Janusz WALCZAK, Seweryn MAZURKIEWICZ

Instytut Elektrotechniki i Informatyki, Politechnika Śląska w Gliwicach

TRANSFORMATIONS OF MOMENTS OF HARMONIZABLE STOCHASTIC SIGNALS IN DETERMINISTIC NONLINEAR SYSTEMS

Summary. The paper presents the method for determining moments of harmonizable stochastic processes occurring in memoryless, and deterministic nonlinear SISO systems. There is assumed that the considered stochastic processes are described by the Fourier series and a nonlinear system is described by the polynomial with deterministic coefficients. There are given formulas determining the mean value, variance, autocorrelation functions and correlation function of the considered processes. The obtained results are illustrated by an example.

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Janusz WALCZAK, Seweryn MAZURKIEWICZ

Instytut Elektrotechniki i Informatyki, Politechnika Śląska w Gliwicach

TRANSFORMATIONS OF MOMENTS OF STOCHASTIC SIGNALS IN THE RANDOM NONLINEAR SYSTEMS

Summary. The paper is a continuation of work [12] and involves determining the moments of stochastic processes in memoryless, SISIO random systems. The considered processes are described by stochastic Fourier series and a nonlinear system is described by a random polynomial. There are given formulas determining the mean value, variance, autocorrelation functions and correlation function of the considered processes. The developed computer program enabling determination of the moments is presented. An example of application of the program is given.

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Grzegorz REDLARSKI

Katedra Mechatroniki i Inżynierii Wysokich Napięć, Politechnika Gdańska

THE ASSESSMENT OF THE ANGULAR SPEED CONTROL SYSTEM MODIFICATION POSSIBILITY IN A STEAM TURBINE FOR THE PURPOSE OF ELIMINATING AN AUTOMATIC SYNCHRONIZER

Summary. This paper presents a proposal to amend the structure of a steam turbine system to eliminate an automatic synchronizer in a classical synchronization process. For this reason the results of many studies and the most important conclusions are presented (the paper was presented at the conference PPEEm 2011).

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Piotr GAS

Akademia Górniczo-Hutnicza, Katedra Elektrotechniki i Elektroenergetyki

INFLUENCE OF THE COAXIAL-SLOT ANTENNA'S INPUT POWER ON TEMPERATURE DISTRIBUTION DURING INTERSTITIAL MICROWAVE HYPERTHERMIA

Summary. In this paper a model which is an example of interstitial microwave hyperthermia acting locally to diseased tissue is presented. A microwave coaxial-slot antenna placed in the liver tissue is a heat source. Due to the axial symmetry of the model, for simplification a two-dimensional case is considered. The presented issue is therefore a coupling of the electromagnetic field and the temperature field. Using the finite element method, the wave equation for TM wave case and the bioheat equation under steady-state condition have been solved. At the end the obtained simulation results for several levels of the antenna total input power are presented.

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