ELEKTRYKA - Issue 3/2010 (215) - Politechnika Śląska, Wydział Elektryczny

ELEKTRYKA - Issue 3/2010 (215)

ELEKTRYKAYear LVI (2010)

QuarterlyIssue 3 (215)

Scientific Committee

CONTENTS

Foreword

Krzysztof BUDNIK, Wojciech MACHCZYŃSKI: Magnetic field of underground cables
Krzysztof GÓRECKI, Janusz ZARĘBSKI: The influence of cooling conditions on characteristics of the linear voltage regulator
Tadeusz BIAŁOŃ, Arkadiusz LEWICKI, Roman NIESTRÓJ, Marian PASKO: Stability of a proportional observer with additional integrators on the example of the flux observer of induction motor
Marek DŁUGOSZ, Wojciech MITKOWSKI, Paweł SKRUCH: Control methods in Chua’s electric circuit
Stefan PASZEK, Piotr PRUSKI: Determination of electromechanical eigenvalues of power system state matrix based on instantaneous power disturbance waveforms
Sebastian BERHAUSEN, Stefan PASZEK: Electromagnetic parameter estimation of synchronous generator with static exciter working in power system
Grzegorz KIEŁTYKA, Janusz WALCZAK: Stability analysis of equlibrium points of nonlinear a fourth order phase-locked loop
Tomasz BISKUP, Arkadiusz DOMORACKI, Aleksander BODORA: Microprocessor implementation of control method for improve properties of drive with BLDC motor
Krzysztof KRYKOWSKI, Grzegorz SIEMEK, Dawid WALCZAK: Inductance impact on pm bldc motor torque-speed characteristics
Łukasz PIĄTEK: Algorithm for finding one and two elements minimal cuts in undirected graph

Krzysztof BUDNIK, Wojciech MACHCZYŃSKI

Instytut Elektrotechniki i Elektroniki Przemysłowej, Politechnika Poznańska

MAGNETIC FIELD OF UNDERGROUND CABLES

Summary. The paper presents a theoretical study of the calculation of magnetic fields in vicinity of underground electric power lines. Exact and simplified methods of the determination of the magnetic flux density are presented. For a straight underground conductor the exact method bases on the Fourier transform technique, whereas the simplified method is based on the Biot-Savart law.

PDF version

Krzysztof GÓRECKI, Janusz ZARĘBSKI

Katedra Elektroniki Morskiej, Akademia Morska w Gdyni

THE INFLUENCE OF COOLING CONDITIONS ON CHARACTERISTICS OF THE LINEAR VOLTAGE REGULATOR

Summary. In the paper the results of experimental investigations showing the influence of the selfheating phenomenon on characteristics of the monolithic voltage regulator 723 are presented. The ideal and real cooling conditions of the voltage regulator mounted in the packages DIL14 and TO-5 operating with a heat-sink and without any heat-sink are considered. The obtained results of measurements show a strong influence of selfheating on the output and transfer characteristics of the application circuits of the considered regulator.

PDF version

Tadeusz BIAŁOŃ, Roman NIESTRÓJ, Marian PASKO

Instytut Elektrotechniki i Informatyki, Politechnika Śląska w Gliwicach

Arkadiusz LEWICKI

Katedra Automatyki Napędu Elektrycznego, Politechnika Gdańska

STABILITY OF A PROPORTIONAL OBSERVER WITH ADDITIONAL INTEGRATORS ON THE EXAMPLE OF THE FLUX OBSERVER OF INDUCTION MOTOR

Summary. The paper describes issues connected with stability of a proportional Luenberger observer with additional integrators. It is proven that there exists a class of observed systems for which discussed observer is always unstable, independent of its gains selection. Stability conditions are presented as well. The problem of stability is solved by replacing additional integrators with modified integrators. It is shown that proper selection of parameters of modified integrators and observer’s gains ensures its stability for every observed system. Experimental results are also presented, these were obtained for the observer of magnetic fluxes of induction motor.

PDF version

Marek DŁUGOSZ, Wojciech MITKOWSKI, Paweł SKRUCH

Katedra Automatyki, Akademia Górniczo-Hutnicza im. S. Staszica w Krakowie

CONTROL METHODS IN CHUA’S ELECTRIC CIRCUIT

Summary. In this paper various control methods of Chua's circuit are proposed. The goal is to stabilise Chua's circuit in unstable equilibria points. The paper contains description of the standard Chua's circuit, see the equation (1) and schema 1, and some modification of this circuit. The nonlinearity (2) was replaced by a piecewise-linear function (11). Figure 4 shows that this simplification is enough if state variables belong to some intervals. By using an idea borrowed from the state observer theory, the proportional full state controller (7) is constructed. The parameters of this controller are obtained by using the pole placement techniques and by solving the linear-quadratic problem. Simulation results show the effectiveness of the proposed controllers, see figures 5, 6, 7 and 8. The second part the paper contains discussion about stabilisation of Chua's circuit in unstable equilibria points by using proportional controller. However, in this case the controller can control only single variable of the state space vector. For these types of controllers, a root locus method is used to analyse the corresponding closed-loop systems (see figures 9, 10 and 11).

PDF version

Stefan PASZEK, Piotr PRUSKI

Instytut Elektrotechniki i Informatyki, Politechnika Śląska w Gliwicach

DETERMINATION OF ELECTROMECHANICAL EIGENVALUES OF POWER SYSTEM STATE MATRIX BASED ON INSTANTANEOUS POWER DISTURBANCE WAVEFORMS

Summary. The paper presents a method and calculation results of electromechanical eigenvalues of the state matrix of the power system multimachine model based on instantaneous power disturbance waveforms in particular generating nodes. The problem of determining the eigenvalues was brought to minimisation of the objective function determined by the deviation vector at particular time instants of the instantaneous power waveforms and those approximating them, calculated on a basis of the searched eigenvalues. The computation results were compared according to the optimisation algorithm selected and the power system model used for simulations.

PDF version

Sebastian BERHAUSEN, Stefan PASZEK

Instytut Elektrotechniki i Informatyki, Politechnika Śląska w Gliwicach

ELECTROMAGNETIC PARAMETER ESTIMATION OF SYNCHRONOUS GENERATOR WITH STATIC EXCITER WORKING IN POWER SYSTEM

Summary. Parameter estimation of the mathematical model of a synchronous generator with a static exciter system working in the power system is presented in the paper. Dynamic waveforms caused by introducing an additional signal in the form of a step change in the reference voltage or a pseudorandom signal to a voltage regulator are the basis for estimation. The influence of the power system stabilizer on the quality of the generator electromagnetic parameter estimation for both disturbances was investigated. The least square method was used for parameter estimation, while the gradient method was applied to minimization of the mean square error.

PDF version

Grzegorz KIEŁTYKA

Zespół Szkół Technicznych w Bytomiu

Janusz WALCZAK

Instytut Elektrotechniki i Informatyki, Politechnika Śląska w Gliwicach

STABILITY ANALYSIS OF EQULIBRIUM POINTS OF NONLINEAR A FOURTH ORDER PHASE-LOCKED LOOP

Summary. The paper presents continuation of work [13] and [14]. In the paper has been made an analysis and was given conditions to the stability of equlibrium points of nonlinear analog phase-locked loop. The PLL loop was cointained the third order Cauer lowpass filter. The stability analysis of the loop has been done using the first Lyapunov method. Presented results were illustrated by example.

PDF version

Tomasz BISKUP, Arkadiusz DOMORACKI, Aleksander BODORA

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

MICROPROCESSOR IMPLEMENTATION OF CONTROL METHOD FOR IMPROVE PROPERTIES OF DRIVE WITH BLDC MOTOR

Summary. The paper is a summary of research in area of a microprocessor system for BLDC motor which improve motion properties by modification of the electronic commutator control method. Prepared control system and electronic commutator can work with three control methods: classical, over commutation and modified overlapping. The results of research are illustrated by oscilloscope measurements.

PDF version

Krzysztof KRYKOWSKI, Grzegorz SIEMEK, Dawid WALCZAK

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

INDUCTANCE IMPACT ON PM BLDC MOTOR TORQUE-SPEED CHARACTERISTICS

Summary. When phase windings of brushless dc motors are switched over, additional voltage drops across main circuit inductances arise. If these voltages are neglected, which is common practice, the calculated speeds are higher than speeds actually measured in real PM BLDC motor. The paper presents analytical method of determining torque-speed characteristics of PM BLDC motor; this method is much more accurate than usually adopted procedure neglecting inductances impact. The proposed method has been worked out by the authors and it takes into account the voltage drops across main circuit inductances. It has been verified by laboratory and simulation tests.

PDF version

Łukasz PIĄTEK

Instytut Informatyki, Politechnika Częstochowska

ALGORITHM FOR FINDING ONE AND TWO ELEMENTS MINIMAL CUTS IN UNDIRECTED GRAPH

Summary. A new algorithm for finding one and two elements cuts in undirected graph was given. The algorithm is based on an unique method for searching the graph. During the finding of one element cuts such subgraphs are found, in which there are no one element cut. These subgraphs are then searched separetely by an unique method. A division of the graph into areas is found. One type of the area is such that each edges in it is in at least one minimal two elements cut. The second type is such that not any edge is in a minimal two elements cut. Areas of the graph where edges are in cuts are used to construct the full set of two elements minimal cuts.

PDF version

Back

Ze względu na uruchomienie nowej witryny Politechniki Śląskiej strona naszego Wydziału dostępna jest pod adresem
www.polsl.pl/re/