- Type of paper
: Paper in journal
Title: Voltage among adjacent commutator bars by unsymmetrical
double lap armature winding of D.C. machine
- Authors:
- Smolčić, Zlatko (105403)
- Gašparac, Ivan (75402)
Journal: Elektrotehnika
Number: 4
ISSN: 0013-5844
Volume: 36
Year: 1993
Pages: from 181 to 188
Language: hrvatski
Summary: The article gives a survey of achievable D.C. machine's
power independency on the speed of rotation for various types of
armaturewinding. Issue of application of unsymmetrical double lap windingis
being considered with the purpose of achieving voltagepulsations among
adjacent commutator bars. A method of numericalcomputation of voltage among
adjacent commutator bars is designedand the influence of armature winding
parameters on that voltageis explored, and suggestions to possible
solutions for thereduction of voltage pulsation among adjacent commutator
bars areprovided.
Keywords: D.C. machine, voltage among commutator bars, numeric method, pulsations reduction, unsymetrical double lap armature winding, achievable machine's power
- Type of paper
: Paper in journal
Title:
- Authors:
- Jadrić, Martin (17591)
- Terzić, Božo (138865)
Journal: Elektrotehnika
Volume: 33
Year: 1990
Pages: from 227 to 235
Language: hrvatski
- Type of paper
: Paper in journal
Title:
- Authors:
- Štefanko, Stjepan
- Jadrić, Martin (17591)
- Božiković, Ljubomir
Journal: Elektrotehnika
Volume: 33
Year: 1990
Pages: from 167 to 179
Language: hrvatski
- Type of paper
: Paper in journal
Title:
- Authors:
- Maletić, Ante (27623)
Journal: Elektrotehnika
Volume: 33
Year: 1990
Pages: from 237 to 243
Language: hrvatski
- Type of paper
: Paper in journal
Title: Technical diagnosis of the induction motor rotor cage
- Authors:
- Wolf, Radenko (54263)
- Ban, Drago (1914)
- Cettolo, Mirko (6721)
- Kovačević, Zoran (81230)
Journal: Elektrotehnika
Number: 5
ISSN: 0013-5844
Volume: 34
Year: 1991
Pages: from 187 to 196
Language: hrvatski
Summary: Failures of rotor are representing a growing percentage
ofbreakdowns at induction cage motors, especially at large ones orthose in
heavy duty drives. Most failures of rotors occur asbreakage of one or more
bars or segments of the ring, caused byinteraction of different strains in
rotor construction. In thispaper a method is given and used to analyse the
distribution ofcurrent in bars and rings of the cage in case of bar break
or ofa segment in ring. Harmonic analysis is applied on the fieldshape in
both cases, reaction of stator currents is analysed, andbearing on the
behaviour of the motor is valued. Based on theresults of theoretical
analysis and of measurements in thelaboratory on an available motor,
conclusions and directions forcontinuing the search of elements for a
reliable methodology oftechnical diagnosis concerning defective states of
rotor cage ofinduction motors, are given.
Keywords: analysis, induction motor, technical diagnostics, rotor cage, failures, measurements
- Type of paper
: Paper in journal
Title:
- Authors:
- Šimunić, Zoran
Journal: Elektrotehnika
Number: 6
ISSN: 1113-5844
Volume: 34
Year: 1991
Pages: from 251 to 258
Language: hrvatski
- Type of paper
: Paper in journal
Title: Detection methods of induction motor rotor cage foults
- Authors:
- Ban, Drago (1914)
- Wolf, Radenko (54263)
- Cettolo, Mirko (6721)
Journal: Elektrotehnika
Number: 6
ISSN: 0013-5844
Volume: 34
Year: 1991
Pages: from 241 to 250
Language: hrvatski
Summary: The paper deals with detection method of an initial foult
(as abreak of the rotor cage bar) on a general application inductionmotor.
The method is based on recording and analysing the signalsin a part of
stator winding or those in specially built in coils,for detecting the
fault. Theoretic analysis and experimentalresults are presented. Theoretic
and experimental methods areapplied to check the possibilities to obtain an
indication of acage foult by measurement and spectral analysis of
axialvibrations on the bearing shields.
Keywords: analysis, induction motor, experiments, faults, detection methods
- Type of paper
: Paper in journal
Title: Determination of the armature magnetomotive force loss due
to the real commutation process in DC-machine
- Authors:
- Obad, Ivan
- Šimunić, Zoran
Journal: Elektrotehnika
Number: 1
ISSN: 0013-5844
Volume: 35
Year: 1992
Pages: from 33 to 41
Language: hrvatski
Summary: Real commutation process in the commutating coil of
DC-machinesdiffers from the idealized one due to the complex
elektromagneticconditions in a commutating zone and due to the
nonlinearcharacteristics of slide contacts between brush and
commutatorsectors. Theoretical and experimental results in finding
therelation between duration and character of the commutationprocess and
magnetomotive force in the commutating zone arepresented. The method of
determination of the armature windingm.m.f. loss due to real commutation
process is described.
Keywords: DC-machine, research, commutation process, armature winding, m.m.f. calculation
- Type of paper
: Paper in journal
Title: Method of experimental identification on the equivalent
circuit parameters for the armature coil of a DC-machine
- Authors:
- Šimunić, Zoran
Journal: Automatika
Number: 1
ISSN: 0005-1144
Volume: 33
Year: 1992
Pages: from 47 to 52
Language: hrvatski
Summary: Due to the rapid changes of the amount of current in
anelectrical machine, the inductance and resistance are presentedby a
complex equivalent circuit, comprising the influence ofeddy-curerents in
copper and iron. Equivalent circuit parameterand frequency response are
estimated by a new method of analysisof the current and voltage amounts in
a transient state. Themethod is tested on the commutating coil of the
DC-machine.
Keywords: experimental estimation, induktance,equivalent circuit, electrical machine, armature coil
- Type of paper
: Paper in journal
Title: Test methods and measuring apparatus for measurement of
dynamic coefficinet of friction of brushes
- Authors:
- Milković, Mateo (123901)
Journal: Carbon
Number: 4
ISSN: 0008-6223
Volume: 30
Year: 1992
Pages: from 587 to 592
Language: engleski
Summary: The coefficient of friction is a very important
operationalcharacteristic of brushes, which is indirectly measured
accordingto conventional mathods by measurement of the tangential
forcesacting on the brush. Methods making possible measurements of
thestatic and dynamic coefficient of friction are suggested becauseonly the
static coefficient of friction can be measured byconventional methods. Two
measuring have been developed anddescribed; an electrical balance can be
used for slower dynamicchanges, and a resistance bridge for faster dynamic
changes.
Keywords: carbon brushes, coefficient of friction, testing methods, pulsating current, cyclic heating
- Type of paper
: Paper in proceedings
Title: Modeling and simulation of the Brushless DC motor drive
- Authors:
- Terzić, Božo (138865)
- Jadrić, Martin (17591)
- Editors
- Srb, Neven
Proceedings title: 05 Energetska tehnika i aditivni izvori energije
Language: hrvatski
Place: Opatija
Year: 1991
Pages: from 166 to 171
Meeting: III međunarodni simpozij o novim tehnologijama
Summary: The strukture of the brushless dc motor drive implemented
as alaboratory model is described. Its mathematical model is thengiven.
Using this model the steady state and dynamic mode ofoperations are
simulated. The simulation and measurement resultsare compared. These
results show very good cocordance whichconfirms the validity of the given
model. To ilustrate the modelapplication the procedure of dc voltage source
selection is givenin relation to limitations of the ripple of
electromagnetictorque.
Keywords: brushless DC motor, mathematical model, simulation, electrical drive
- Type of paper
: Paper in proceedings
Title:
- Authors:
- Ilić, Ivan (17001)
- Ban, Drago (1914)
Proceedings title: Zbornik radova 3. SONT
Language: engleski
Place: Zagreb
Year: 1991
Pages: from 21 to 22
Meeting: III međunarodni simpozij o novim tehnologijama
- Type of paper
: Paper in proceedings
Title: Computation of steady-state performance of a brushless dc
motor
- Authors:
- Terzić, Božo (138865)
- Jadrić, Martin (17591)
Proceedings title: Zbornik radova 37. Međunarodni godišnji skup KoREMA
Language: hrvatski
Place: Zagreb
Year: 1992
Pages: from 498 to 502
Meeting: 2nd international conference Design to manufacture in modern industry
Held: from 04/26/92 to 04/29/92
Summary: The paper describes the calculation method of
staticcharacteristics of brushless dc motor with cylindrical rotor andthe
trapezium-shaped elektromotive force. All the necessaryequtations are given
expčicitly in relation to rotation speed andmotor parameters. To define the
swiching time appearing as aparameter in phaze current expressions, the
iterative method ofsolving the transcendent equation is applied, so that
electroniccomputer must be used for calculations. The calculation
andmeasurement results are compared for current wave forms and themoment
characteristic, and accurancy of the described calculationmethod is
confirmed.
Keywords: ellectronicaly commutated motor, commutation, steady state of operation, torque characteristic
- Type of paper
: Paper in proceedings
Title:
- Authors:
- Kovačić, Tihomir (163003)
- Maljković, Zlatko (27746)
Proceedings title: Zbornik radova 37. Međunarodni godišnji skup KoREMA
Language: hrvatski
Place: Zagreb
Year: 1992
Pages: from 38 to 41
Meeting: 2nd international conference Design to manufacture in modern industry
- Type of paper
: Paper in proceedings
Title:
- Authors:
- Maljković, Zlatko (27746)
- Glavan, Boris
Proceedings title: Zbornik radova 37. Međunarodni godišnji skup KoREMA
Language: hrvatski
Place: Zagreb
Year: 1992
Pages: from 111 to 115
Meeting: 2nd international conference Design to manufacture in modern industry
- Type of paper
: Paper in proceedings
Title: Identification and adaptation on rotor resistance changes
in vector controlled drive with induction machine
- Authors:
- Zdenković, Josip (185145)
- Kuljić, Zoran
- Čanić, Šimun
- Perkovac, Milan
Proceedings title: Proceedings 37th International Annual Gathering KoREMA
Language: hrvatski
Place: Zagreb
Year: 1992
ISBN/ISSN: 86-81571-11-7
Pages: from 486 to 489
Meeting: Symposium on electrical drives and power electronics
Held: from 04/26/92 to 04/27/92
Summary: The identity of supposed and real value of rotor resistance
has
significant influence on dynamic behaviour of vector controlled
drive with induction machine. Description of an identification
and adaptation algorithm concernig rotor resistance changes is
given. Results of applied method achieved with realized vector
control system for 4 kW induction machine are shown. Control unit
containing two digital signal processors TMS320E14 is presented.
Keywords: vector control, induction machine, signal processor, rotor resistance identification
- Type of paper
: Paper in proceedings
Title: Additional losses of electronically commutated motor
- Authors:
- Jadrić, Martin (17591)
- Terzić, Božo (138865)
- Editors
- Srb, Neven
Proceedings title: Zbornik 6. Međunarodnog savjetovanja o elektromotornim pogonima
Language: hrvatski
Place: Zagreb
Year: 1992
Pages: from 54 to 57
Meeting: 6. Međunarodno savjetovanje o elektromotornim pogonima
Held: from 10/13/92 to 10/15/92
Summary: Additional losses of electronically commutated motor
aredefined. The procedure for their determination, based onmeasurement of
impedance characteristic and the given shape ofthe current wave is shown.
The results are obtained combiningmeasuring and calculation procedure for
the motor having thepower rate of 1.5 kW. The current pulsation effect on
additionallosses is analyzed.
Keywords: electronically commutated motor, additional losses
- Type of paper
: Paper in proceedings
Title:
- Authors:
- Kunjašić, Đino (153274)
Proceedings title: Zbornik 6. Međunarodnog savjetovanja o elektromotornim pogonima
Language: hrvatski
Place: Brijuni, HR
Year: 1992
Pages: from 109 to 114
Meeting: 6. Međunarodno savjetovanje o elektromotornim pogonima
Held: from 10/13/92 to 10/15/92
- Type of paper
: Paper in proceedings
Title: Rotor time constant identification method in vector
controlled drive with induction machine
- Authors:
- Zdenković, Josip (185145)
- Horvat, M.
- Kuljić, Zoran
- Čanić, Šimun
- Klobučar, Veljko
- Perkovac, Milan
- Editors
- Srb, Neven
- Majić, Mirko
- Car, Stjepan
Proceedings title: 6th International conference on electric-motor drives
Language: hrvatski
Place: Zagreb
Year: 1992
ISBN/ISSN: -
Pages: from 142 to 148
Meeting: 4. međunarodni simpozij o novim tehnologijama
Held: from 10/13/92 to 10/15/92
Summary: Description of an on line identification and adaptation
algorithm
concernig rotor time constant changes is given. Method is based
on estimation of both the active and the reactive power
transferred to the rotor. Only the premeasured values of stator
resistance and total leakage inductance are needed in addition
to instantaneously measured stator current and voltages. Results
of computer simulation of relevant operating conditions with
applied method are presented. The method is experimentaly
verified on 4 kW vector controlled drive with cage induction
machine.
Keywords: vector control, induction machine, digital signal processor, rotor time constant identification
- Type of paper
: Paper in proceedings
Title:
- Authors:
- Bušić, Krešimir
- Šimunić, Zoran
Proceedings title: Zbornik 6. Međunarodnog savjetovanja o elektromotornim pogonima
Language: hrvatski
Place: Brijuni, HR
Pages: from 149 to 154
Meeting: 6. Međunarodno savjetovanje o elektromotornim pogonima
Held: from 10/13/92 to 10/15/92
- Type of paper
: Paper in proceedings
Title:
- Authors:
- Smolčić, Zlatko (105403)
Proceedings title: Zbornik 6. Međunarodnog savjetovanja o elektromotornim pogonima
Language: hrvatski
Place: Brijuni, HR
Year: 1992
Pages: from 162 to 166
Meeting: 6. Međunarodno savjetovanje o elektromotornim pogonima
Held: from 10/13/92 to 10/15/92
- Type of paper
: Paper in proceedings
Title:
- Authors:
- Ban, Drago (1914)
- Wolf, Radenko (54263)
- Cettolo, Mirko (6721)
- Grgić, I.
Proceedings title: Zbornik 6. Međunarodnog savjetovanja o elektromotornim pogonima
Language: hrvatski
Place: Brijuni, HR
Year: 1992
Pages: from 256 to 259
Meeting: 6. Međunarodno savjetovanje o elektromotornim pogonima
Held: from 10/13/92 to 10/15/92
- Type of paper
: Paper in proceedings
Title:
- Authors:
- Šimunić, Zoran
Proceedings title: Proceedings 4th International Conference IMACS-TCI'93
Language: engleski
Place: Montreal, Canada
Year: 1993
Pages: from 293 to 298
Meeting: 4th International Conference IMACS-TC1'93
- Type of paper
: Paper in proceedings
Title:
- Authors:
- Ban, Drago (1914)
- Cettolo, Mirko (6721)
Language: hrvatski
Year: 1993
Pages: from 8 to 13
Meeting: 1. Međunarodno savjetovanje o održavanju i popravku električne opreme
- Type of paper
: Paper in proceedings
Title: One method for indirect speed estimation in vector
controlled induction machine drives
- Authors:
- Zdenković, Josip (185145)
- Kuljić, Zoran
- Čanić, Šimun
- Perkovac, Milan
- Kuljić, Zoran
Proceedings title: 5th European Conference on Power Electronics and Aplications
Language: engleski
Place: Exeter, UK
Year: 1993
ISBN/ISSN: 085296 5869
Pages: from 399 to 404
Meeting: 5th European Conference on Power Electronics and Applications EPE'93
Held: from 09/13/93 to 09/16/93
Summary: In order to improve the robustness of vector controlled
induction
machine drive, the direct speed measurement should not be
applied. One method for indirect speed estimation, which permits
speed estimation from stator voltage equation in field
coordinates is introduced. Presumption that rotor flux vector
modulus is held constant and total leakage factor considered to
be zero are used. Speed estimator is applied to the indirect
field orientation control structure. Simulation results and
experimental verification on real 4kW drive show that good
behaviour is obtained in static conditions under variable load
and in dynamic conditions under stepwise speed reference changes.
The dynamic and static performance are still acceptable even if
error in assumed values for stator and rotor resistance exists.
Control unit contains two digital signal processors in parallel
work. Inverter is realized with IGBTs.
Keywords: induction machine, vector control, sensorless drive, digital signal processor
- Type of paper
: Paper in proceedings
Title: An approach to the life extension and refurbishment
problem of generator excitation system
- Authors:
- Sirotić, Zvonimir
- Ban, Drago (1914)
- Erceg, Gorislav
- Galić, Damjan
- Maljković, Zlatko (27746)
- Puzak, Milivoj
Language: hrvatski
Place: Zagreb
Year: 1993
Pages: from 31 to 40
Meeting: Prvo savjetovanje Hrvatskog komiteta CIGRE
Held: from 10/10/93 to 10/13/93
Summary: Tre current stage of larger power plants excitation systems
inCroatia is briefly presented in this paper, and general trends
inrefurbishment of synchronous generator excitation system areconsidered.
An approach to the problem of life extension,reconstruction and
refurbishment of turbogenerator excitationsystem, which operates more than
twenty years, is described onthe example of one turbogenerator. The
problems of worn out stateof some excitation system components, and trends
of new, modernsolutions are considered. For the concrete example, the
staticexcitation system is prefered. The influence of change ofexcitation
system on stability of electric power system od Istriais also considered.
Keywords: synchronous generator, excitation systems, life extension
- Type of paper
: Paper in proceedings
Title: Some life extension specialities of hydrogenerator
excitation system
- Authors:
- Maljković, Zlatko (27746)
- Erceg, Gorislav
- Srb, Neven
- Smolčić, Zlatko (105403)
Proceedings title: Prvo savjetovanje hrvatskog komiteta CIGRE
Language: hrvatski
Place: Zagreb
Year: 1993
Pages: from 51 to 10
Meeting: Prvo savjetovanje Hrvatskog komiteta CIGRE
Held: from 10/10/93 to 10/13/93
Summary: The paper analizes, on the real example of hydrogenerator,
fewvariants of excitation system reconstruction, specially
possiblereconstructions of the main exciter, with the purpose of
reliablerealization of excitation system, and with minimum request forthe
maintance. The problem of worn out state of some excitationsystem component
and the choise of new modern solutionsare analized. Variants of complete
and partial replacement ofexcitation system components are valorized.
Keywords: hydrogenerator, excitation system, life extension, DC and AC generator
- Type of paper
: Paper in proceedings
Title: Diagnostic methods development for internal power
consumption motors of the thermal power plant
- Authors:
- Ban, Drago (1914)
- Wolf, Radenko (54263)
- Cettolo, Mirko (6721)
- Kovačević, Zoran (81230)
Proceedings title: Prvo savjetovanje hrvatskog komiteta CIGRE
Language: hrvatski
Place: Zagreb
Year: 1993
Pages: from 83 to 91
Meeting: Prvo savjetovanje Hrvatskog komiteta CIGRE
Held: from 10/10/93 to 10/13/93
Summary: This paper emphasizes problems of the induction motor's
rotorsensitivity on failure in the working conditions. It also givesan
overview of the methods that enable "ON-LINE" failurediagnostics in the
working conditions, and "OFF-LINE" diagnosticwhen the motor is out of work.
Results of the failure researchusing diagnostics methods based on
computerized spectrum analysisof the stator current are presented and
commented on.
Keywords: induction motor, technical diagnostics, harmonic analysis, stator current
- Type of paper
: Paper in proceedings
Title: Coomputerized "ON-LINE" diagnostics of large induction
motors
- Authors:
- Ban, Drago (1914)
- Wolf, Radenko (54263)
- Cettolo, Mirko (6721)
Proceedings title: 4. međunarodni simpozij o novim tehnologijama
Language: hrvatski
Place: Pula
Year: 1993
ISBN/ISSN: 86-81997
Pages: from 80 to 83
Meeting: 4. međunarodni simpozij o novim tehnologijama
Held: from 10/25/93 to 10/27/93
Summary: After a brief retrospect of the problems connected
withoperational sensitivity of the squirrel-cage motor, a review ofmore or
less known methods for "ON-LINE" i "OFF-LINE" faultdiagnostics of such
rotor is given. The results in application ofnew diagnostic methods, based
on usage of the contemporarymeasuring and computer equipment and
commerciallyavailablesoftware, are particulary presented.
- Type of paper
: Paper in proceedings
Title: Speed control system design with adaptive controller for
electronically commutated servomotor drives
- Authors:
- Terzić, Božo (138865)
Proceedings title: Zbornik IV međunarodnog simpozija o novim tehnologijama
Language: hrvatski
Place: Pula
Year: 1993
Pages: from 0 to 0
Meeting: 4. međunarodni simpozij o novim tehnologijama
Held: from 10/25/93 to 10/27/93
Summary: Adaptive speed controller which, depending upon error
signal,operates as bang-bang or PI controller, was aplied onelectronically
commutated servomotor drive. Simplifiedmathematical model of system was
established, and design of speedcontrol loop has been done. Simulating and
experimental resultsshow the advantages of the adaptive controller over the
classicalPI controller.
- Type of paper
: Paper in proceedings
Title: Problems of the reactive power compensation at singlephaze
variable loads
- Authors:
- Božiković, Ljubomir
- Jadrić, Martin (17591)
Proceedings title: IV međunarodni simpozij o novim tehnologijama
Language: hrvatski
Place: Pula
Year: 1993
ISBN/ISSN: 86-81997
Pages: from 29 to 32
Meeting: 4. međunarodni simpozij o novim tehnologijama
Held: from 10/25/93 to 10/27/93
Summary: Different possibilities of balancing the variable loads at
givennodes of the threephaze power system are considered. Amathematical
model of the compensation plant which includes loadbalancing has been
established. The results of simulation arepresented.
- Type of paper
: Paper in proceedings
Title: Electrical drives with induction machines and frequency
converters
- Authors:
- Zdenković, Josip (185145)
- Klobučar, Veljko
- Perkovac, Milan
- Editors
- Katić, Zvonko
Proceedings title: IX međunarodno savjetovanje tehnologa sušenja i skladištenja
Language: hrvatski
Place: Zagreb
Year: 1993
ISBN/ISSN: 953-6135-00-0
Pages: from 199 to 210
Meeting: IX međunarodno savjetovanje tehnologa sušenja i skladištenja
Held: from 01/26/93 to 01/27/93
Summary: The advantages and disadvantages of induction machine are
briefly
outlined. Results of research and development work that is
carried out in private company Drives & Control on the field of
controlled electrical drive with induction machine are presented.
There are several product developed: MIPROSTART - soft starter,
MINIPREF, MIPROVERT, VEKTOREG - frequency converters, MIKON1,
MIPROLIFT-C - programmable control units. Proper way of
selection of induction machine and adequate frequency converter
MIPROVERT is explained in detail.
Keywords: electrical drive, induction machine, frequency converter
- Type of paper
: Paper in proceedings
Title: Speed estimation method in vector controlled induction
machine drive without shaft enkoder
- Authors:
- Zdenković, Josip (185145)
- Kuljić, Zoran
- Čanić, Šimun
- Klobučar, Veljko
- Perkovac, Milan
Proceedings title: Proceedings 38th International Annual Conference KoREMA
Language: hrvatski
Place: Zagreb
Year: 1993
ISBN/ISSN: 953-6037-00-9
Pages: from 599 to 604
Meeting: Electrical drives and power electronics
Held: from 04/26/93 to 04/26/93
Summary: In order to improve the robustness of vector controlled
induction
machine drive the direct speed measurement should not be applied.
The aim of this paper is to present one method for indirect speed
estimation, which permits to estimate speed from stator voltage
equation in field coordinates with presumptions that rotor flux
vector magnitude is held constant and total leakage factor
considered to be zero. Method is applied in the indirect field
orientation structure. Simulation results show that good
behaviour is obtained in steady state condition under load and
dynamic condition under stepwise speed and load reference
changes, regardless even if some error exists in assumed values
for stator and rotor resistance.
Keywords: vector control, induction machine, digital signal processor, speed estimation
- Type of paper
: Paper in proceedings
Title: Signal Processor Base Frequency Converter for field
Oriented Vektor Controlled Induction Machine Drive
- Authors:
- Zdenković, Josip (185145)
- Kuljić, Zoran
- Čanić, Šimun
- Perkovac, Milan
- Editors
- Solina, Franc
- Zajc, Baldomir
Proceedings title: Proceedings of the Second Electrotehnical and Computer Science Conference ERK'93
Language: engleski
Place: Ljubljana, Slovenija
Year: 1993
ISBN/ISSN: -
Pages: from 305 to 308
Meeting: 2nd Electrotehnical and Computer Science Conference ERK'93
Held: from 09/27/93 to 09/29/93
Summary: The application off up to date electronic components as the
digital signal processor in the control unit and the IGBT
switches in the inverter unit for induction machine vector
controlled drive is considered. Interesting hardware and software
design features of realized industrial frequency converter
VEKTOREG are presented. Two digital signal processors work
parallel in order to get complete digital current, torque, speed
and position control. Excellent torque and flux control
decoupling is achieved through rotor flux vector orientated
control. Various possibilities of converter control and
interfaces are discussed. Algorithm applied for the on-line rotor
time constant parameter adaptation are briefly introduced. Some
experimental results are presented.
Keywords: vector control, frequency converter, induction machine, digital signal procesor
- Type of paper
: Paper in proceedings
Title: Contemporary diagnostic methods for induction motors of
middle and large rating
- Authors:
- Ban, Drago (1914)
- Wolf, Radenko (54263)
- Kovačević, Zoran (81230)
- Cettolo, Mirko (6721)
Language: engleski
Year: 1993
Pages: from 0 to 0
Meeting: 1st international conference on maintance and repair of electrical equipment
Held: from 05/21/93
- Type of paper
: Paper in proceedings
Title: Modern solution of the wood pulp bleaching process
regulation
- Authors:
- Šimunić, Zoran
- Kovačić, Tihomir (163003)
- Rabuzin, Zdravko (190694)
- Himelreich, Zvonimir
Proceedings title: IV međunarodni simpozij o novim tehnologijama
Language: hrvatski
Place: Pula
Year: 1993
ISBN/ISSN: 86-81977
Pages: from 57 to 62
Meeting: 4. međunarodni simpozij o novim tehnologijama
Held: from 10/25/93 to 10/27/93
Summary: During the wood pulp industrial plant automatization
thereconstruction and automatization of the bleaching process wasalso done.
The new equipment for measuring bleach, flow andconsistency of the deluted
wood pulp and for measuring the restof chemicals was built in. The new
control and regulation system, consisting of two levels, was created. All
control functions andall regulation circuits are realized in the lover
level, operatorlocal process monitoring system. The higher level,
centralprocess monitoring system, is used for production processmonitoring
and for setting technological parameters of thebleached wood pulp
production. The object of the processreconstruction was to achieve a
process with stabile value of thewood pulp output bleach, and to cut out
the use of chemicals asmuch as possible. This paper describe the solution
of processregulation, regulation structure definement, computer
simulationand the final solution after process starting up. All
regulationsand control functions are implemented in a PLC with
processvisualisation. The local and the central control level areconnected
via industrial communication network.
- Type of paper
: Paper in proceedings
Title: Computer aided testing and evaluating electromotor
insulation conditions on site
- Authors:
- Ban, Drago (1914)
- Kovačević, Zoran (81230)
- Cettolo, Mirko (6721)
- Editors
- Jezernik, Anton
Proceedings title: Proc. 2d international conference Design to manufacture in modern industry
Language: engleski
Place: Bled, Slovenia
Year: 1995
ISBN/ISSN: 86-435-0108-5
Pages: from 619 to 624
Meeting: 2nd international conference Design to manufacture in modern industry
Held: from 05/29/95 to 05/30/95
Summary: This paper presents the measurement method and the test
results of motor insulation condition in the cement factory. Several levels
of stabilized d.c. voltage are suplied to motor winding, with precisely
defined value and duration of each level. The voltage and the leakage
current through the insulation are recorded using PC, AD converter and
appropriate software. This measurement method is applicable for motor
insulation testing on site, regardless the motor size.
- Type of paper
: Paper in proceedings
Title: Experimental determination of brushless DC motor
parameters
- Authors:
- Gašparac, Ivan (75402)
- Ban, Drago (1914)
- Maljković, Zlatko (27746)
- Editors
- Jakopović, Željko
- Kovačić, Zdenko
Proceedings title: Proceedings 40th anniversary conference KoREMA
Language: engleski
Place: Zagreb
Year: 1995
ISBN/ISSN: 953-6037-08-4
Pages: from 571 to 574
Meeting: 40th anniversary conference KoREMA
Held: from 04/19/95 to 04/21/95
Summary: The article deals with a method of determining the
inductance and electrical time constant of electronically commutated motors
provided with permanent magnets on the rotor. By recording and analyzing
the current response of a stator winding connected to a constant voltage
source, the values of inductance and time constant necessary for the
analysis of motor behaviour in transient conditions are obtained. The
experiment was carried out for direct and quadrature position of stator
winding axis in relation to the axis of the permanent magnet on the rotor.
The measurement results obtained on a concrete brushless DC motor are
presented.
Keywords: brushless DC (electronically commutated) motor, inductances, time constants
- Type of paper
: Paper in proceedings
Title: esting and evaluating of electromotr insulation conditions
on site using computer
- Authors:
- Ban, Drago (1914)
- Kovačević, Zoran (81230)
- Cettolo, Mirko (6721)
- Editors
- Jakopović, Željko
Proceedings title: Proceedings 40th anniversary conference KoREMA
Language: engleski
Place: Zagreb
Year: 1995
ISBN/ISSN: 953-6037-08-4
Pages: from 567 to 570
Meeting: 40th anniversary conference KoREMA
Held: from 04/19/95 to 04/21/95
Summary: This paper presents the measurement method and the test
results of motor insulation condition in the cement factory. Several levels
of stabilized d.c. voltage are supplied to motor winding, with precisely
defined value and duration of each level. The voltage and the leakage
current through the insulation are recorded using PC, AD converter and
appropriate software. This measurement method is applicable for motor
insulation testing on site, regardless the motor size. Two measurements
were carried out, according to this measurement method, at 10-months
interval. The analysis and processing of the test results show that the
method is acceptable because it gave enough data for the decision about
possible improvement of insulation conditions.
- Type of paper
: Paper in proceedings
Title: Some aspects of electrical drive selection for propulsion
od eco-ship
- Authors:
- Ban, Drago (1914)
- Gašparac, Ivan (75402)
- Nevešćanin, Mate
- Editors
- Benčić, Zvonimir
- Perić, Nedjeljko
- Rajković, Borivoje
- Srb, Neven
Proceedings title: Proc. of the 8th int. conference on electrical drives and power electronics
Language: engleski
Place: Zagreb
Year: 1994
ISBN/ISSN: 953-6037-04-1
Pages: from 287 to 290
Meeting: 8th international conference on electrical drives and power electronics
Held: from 09/12/95 to 09/14/95
Summary: This paper presents one realisation of the electrical drive
propulsion of the boat for tourist purposes. Because of the boat's purpose
and the design solutions, the DC electrical drive with chopper based speed
control system employing mechanical gearbox is chosen. Power supply is
realized from accimulator batteries. Drive wheel with paddles
("Mississippi" system) is used instead of propeller in order to increase
attraction for tourists.
Keywords: electrical drive, eco-boat
- Type of paper
: Paper in proceedings
Title: One solution of electrical drive of bicycle
- Authors:
- Nevešćanin, Mate
- Maljković, Zlatko (27746)
- Miletić, Marinko
- Ban, Drago (1914)
- Gašparac, Ivan (75402)
- Editors
- Benčić, Zvonimir
- Perić, Nedjeljko
- Rajković, Borivoje
- Srb, Neven
Proceedings title: Proc. of the 8th international conference on el. drives and power electronics
Language: hrvatski
Place: Pula
Year: 1994
ISBN/ISSN: 953-6037-04-1
Pages: from 283 to 286
Meeting: 8th international conference on electrical drives and power electronics
Held: from 09/12/94 to 09/14/94
Summary: In the paper some solution of additional cicycle electrical
drive
are presented. Permanent magnet synchronous motor drive connected
with drive wheel through cog-wheels and chains system is described in
detail. Characteristics of motor and transistor-converters which
represented energy part of this electromotor drive are described.
Keywords: bicycle drive, permanent-magnet synchronous motor
- Type of paper
: Paper in proceedings
Title: The analyses of retardation consequences on turboset with
field current
- Authors:
- Maljković, Zlatko (27746)
- Sirotić, Zvonimir
- Ban, Drago (1914)
- Editors
- Cvetković, Zorko
Proceedings title: Zbornik 2. savjetovanja CIGRE
Language: hrvatski
Place: Šibenik
Year: 1995
ISBN/ISSN: 953-6408-01-5
Pages: from 15 to 24
Meeting: Međunarodna konferencija za velike el. sisteme - 2. savjetovanje
Held: from 05/14/95 to 05/18/95
Summary: The consequences of 376 MVA turbine-generator set
retardation are analyzed. Turboset was disconnected from the network
because of electrical system disturbance but owing to field current switch
failure, excitation wasn't switched off. Usin computer's program, rotor and
stator winding heating are computed and influence of overheating on
insulation is evaluated. The time of retardation and field current value
limiting are the most important factors in this case. Rotor temperature was
not higher than 159 oC assuming the duration of retardation with excitation
was 10 min.
Stator heating was within the limits taking into account the changing of
stator losses.
Keywords: turbine-generator, losses, excitation
- Type of paper
: Paper in proceedings
Title: Application of one diagnostic "on-line" method on large
induction motors in preventive maintance of drives
- Authors:
- Ban, Drago (1914)
- Wolf, Radenko (54263)
- Cettolo, Mirko (6721)
- Kovačević, Zoran (81230)
Proceedings title: Energetska i procesna postrojenja-zbornik radova
Language: hrvatski
Place: Dubrovnik
Year: 1994
Pages: from 527 to 531
Meeting: Energetska i procesna postrojenja
Held: from 05/25/94 to 05/27/94
Summary: The paper presents a review methods for rotor condition
diagnostics of large induction motors in power and processing plants. A
contemporary method, based on computerized rotor condition diagnosis, is
presented in details with the results of its application in one concrete
proccesing plant. The performance of this method is that is performed in
operating conditions, without interruption and disturbance of the
technological process.
Keywords: induction motor, technical diagnostic, preventive maintance
- Type of paper
: Paper in proceedings
Title: Digital speed controller design for electronically
commutated motor drive
- Authors:
- Terzić, Božo (138865)
- Editors
- Benčić, Zvonimir
- Perić, Nedjeljko
- Rajković, Borivoje
- Srb, Neven
Proceedings title: Proc. of the 8th international conference on el. drives and power electronics
Language: hrvatski
Place: Pula
Year: 1994
ISBN/ISSN: 953-6037-04-1
Pages: from 182 to 185
Meeting: 8th international conference on electrical drives and power electronics
Held: from 09/12/94 to 09/14/94
Summary: Sigital speed control of the electronically commutated
motor is described. Motor is fed by IGBT inverter. To control the phase
currents, analog hysteresis controllers are used. Commutaton and speed
control is implemented using microcontroller MC68HC11. Using linear model
of continous time system mathematical model of digital speed control is
made. Behaviour of the discrete time system is analised on the basis of the
transformed continous system. Speed controller parameters of the
transformed continous time system are also the parameters of the digital
controller. To verify speed controller design, the laboratory digital speed
control is made. The speed responses on the reference step of 3% of the
nominal value (small signal response) for continous and discrete time
system are compared.
Keywords: induction motor, technical diagnostic, preventive maintenance
- Type of paper
: Paper in proceedings
Title: Active load drive starting and brake control by digital DC
converter
- Authors:
- Kunjašić, Đino (153274)
- Editors
- Benčić, Zvonimir
- Perić, Nedjeljko
- Rajković, Borivoje
- Srb, Neven
Proceedings title: Proc. of the 8th international conference on el. drives and power electronics
Language: hrvatski
Place: Pula
Year: 1994
ISBN/ISSN: 953-6037-04-1
Pages: from 194 to 197
Meeting: 8th international conference on electrical drives and power electronics
Held: from 09/12/94 to 09/14/94
Summary: Speed control problems during active load DC- drive
starting are considered. Function block for brake control, inplemented in
digital DC-converter ABB-VERITRON is described. For a few different
adjustments of torque proofing duration & level at "fixed pocket" drive
(stavking area of steel rolling mill), experimentač results and analysis
are presented.
Keywords: digital DC-converter, active load, brake control, torque proofing
- Type of paper
: Paper in proceedings
Title: The induction machine vector controlled drive in the
volumetric dosage application
- Authors:
- Zdenković, Josip (185145)
- Kuljić, Zoran
- Čanić, Šimun
- Perkovac, Milan
- Klobučar, Veljko
- Editors
- Benčić, Zvonimir
- Perić, Nedjeljko
- Rajković, Borivoje
- Srb, Neven
Proceedings title: Proc. of the 8th international conference on el. drives and power electronics
Language: engleski
Place: Zagreb
Year: 1994
ISBN/ISSN: 953-6037-04-1
Pages: from 233 to 236
Meeting: 8th international conference on electrical drives and power electronics
Held: from 09/12/94 to 09/14/94
Summary: Digital controlled drive in dosage machine is presented.
Precise material volumetric dosing is ensured through dosing worm position
control. The inducion machine is vector controlled by freqiency converter
VEKTOREG. It the first domestic frequency converter with vector control
capability ensuring precise machine shaft positioning. Some converter
design features are discussed. Power part contains IGBT switches. Converter
control unit containing two Digital Processors is briefly introduced.
Experimental results shown clearly confirm achieved overall system
performances.
Keywords: induction machine, volumetric dosing, vector control, digital control
- Type of paper
: Paper in proceedings
Title: Turbine-generator set transients caused by a single-phase
short circuit: a comparison of simulated and test results
- Authors:
- Maljković, Zlatko (27746)
- Kuterovac, Ljiljana
- Gašparac, Ivan (75402)
- Editors
- Ertan, H.Bulent
- Uctug, M.Yildirm
Proceedings title: Proc. of international aegean conference on el. machines and power electronics
Language: engleski
Place: Kusadasi, Turkey
Year: 1995
ISBN/ISSN: 975-429-081-4
Pages: from 181 to 185
Meeting: International aegean conference on electrical machines and power electronics
Held: from 06/05/95 to 06/07/95
Summary: Unbalanced short circuits, especially ones close to a
generator, belong to a group of faults which, beside the electrical,
results with considerable mechanical strains of a turbine-generator set and
can eventually bring to its life expenditure. Although not the severest
from the standpoint of strain per incident, they occur more often than some
more severe disturbances and can contribute to the cumulative demaging of a
turbine-generator shaft. The paper presents the comparison of the results
of computing transient phenomena after a phase-to-neutral short circuit by
a mathematical model to the results obtained by measurements on a
laboratory model. A 2d-1q mathematical representation of a synchronous
generator usual in transient power system studies is used with addition of
a mathematical representation of motion of masses of a turbine-generator
set. Electrical and mechanical occurrences important for the evaluation of
turbine-generator strains are presented.
- Type of paper
: Paper in proceedings
Title: Overvoltage protection of the induction generator after
its disconection from the power grid
- Authors:
- Terzić, Božo (138865)
- Gotovac, S.
- Jadrić, Martin (17591)
Language: engleski
Place: Krakow
Year: 1995
Meeting: 6. International DAAM Symposium "Inteligent manufacturing systems
- Type of paper
: Paper in proceedings
Title: Energy savings in electrical drives with frequency
converter and induction machine
- Authors:
- Zdenković, Josip (185145)
- Kuljić, Zoran
- Klobučar, Veljko
- Perkovac, Milan
- Editors
- Katić, Zvonko
Proceedings title: Xth international symposium of technologies for drying and storing
Language: hrvatski
Place: Zagreb
Year: 1994
Pages: from 342 to 350
Meeting: Xth international symposium of technologies for drying and storing
Held: from 01/18/94 to 01/21/94
Summary: The advantages and disadvantages of induction machine drive
are briefly outlined. Results of research and development work that is
carried out in private company Drives & Control in the field of controlled
electrical drive with induction machine are presented. There are several
product developed: MIPROSTART - soft starter, MINIPREF, MIPROVERT, VEKTOREG
- frequency converters, DPR, MIPROLIFT-C - programmable control units.
Possibilities of energy saving while using induction machine together with
frequency converter in pump or fan drives are discussed in detail. Two
examples of energy saving calculation, where fun and pump drive work some
time period only partially loaded, are further presented.
Keywords: electrical drive, energy saving, frequency converter, induction machine.
- Type of paper
: Paper in proceedings
Title: The system-dynamical connections between several induction
machine rotor flux
- Authors:
- Zdenković, Josip (185145)
- Kuljić, Zoran
- Klobučar, Veljko
- Perkovac, Milan
Proceedings title: Proceedings 39th annual conference KoREMA
Language: hrvatski
Place: Zagreb
Year: 1994
Pages: from 339 to 343
Meeting: 39th annual conference KoREMA
Held: from 04/25/94 to 04/27/94
Summary: In this paper system-dynamical connections between several
methods of rotor flux estimation concerning the induction machine with
squirell-cage rotor are pointed out. The current modell, the voltage model
as well as complete observer and reduced observer are compared. It is shown
that both current and voltage model are equivalent to a reduced observer
with specifically chosen observer coefficients. The reduced observer is
further represented as a limiting case of the complete observer.
Keywords: induction machine, vector control, observer, state estimation
- Type of paper
: Paper in proceedings
Title: The devices for digital control of induction machine-the
experience survey after 1.5MW installed power
- Authors:
- Zdenković, Josip (185145)
- Babić, Zdravko
- Bilić, Mario
- Klobučar, Veljko
- Perkovac, Milan
- Vukas, Vladimir
- Editors
- Benčić, Zvonimir
- Perić, Nedjeljko
- Rajković, Borivoje
- Srb, Neven
Proceedings title: Proc. of the 8th international conference on el. drives and power electronics
Language: engleski
Place: Zagreb
Year: 1994
Pages: from 108 to 114
Meeting: 8th international conference on electrical drives and power electronics
Held: from 09/12/94 to 09/14/94
Summary: Interesting features of frequency converter and voltage
controlled soft starting devices for induction machines are discussed.
Energy saving physical background with frequency converter utilization in
fun and pump drives is explained. The connection of the frequency converter
to the mains should be careful considered in order to suppress interference
problems. Measured current and speed waveforms during various ways of
connecting induction machine to the mains clearly point out the reasons of
soft starting device application
Keywords: frequency converter, soft start, induction machine, energy saving
- Type of paper
: Paper in proceedings
Title: Seed sensorless drive with induction machine based on
natural field orientation
- Authors:
- Zdenković, Josip (185145)
- Kuljić, Zoran
- Pašalić, Nedžat
Proceedings title: 6th european conference on power electronics and applications, Proceedings
Language: engleski
Place: Bruessels, Belgium
Year: 1995
Pages: from 1752 to 1757
Meeting: 6th european conference on power electronics and aplications
Held: from 09/19/95 to 09/21/95
Summary: The speed sensorless drive in indirect vector control
scheme with acting on stator voltage vector is realized by excluding the
speed sensor and including the current measurement. The decoupling circuit
and the speed estimator are based on Natural Field Orientation
presumptions: the rotor flux vector modulus is held constant and the total
leakage factor is zero. The sensorless drive is tested on laboratory set up
where another induction machine operating in torque control mode is used
for loading. Steady state characteristics are presented together with
system responses to speed reference reversing under no load condition and
system responses during stepwise loading processes. Influence of the
machine stator and rotor resistance thermal changes, and changes in the
main machine inductance during machine operation on the behaviour of the
proposed control structure is discussed. Simplicity of the proposed control
algorithms allows implementation in low cost microcontroller hardware.
Keywords: induction machine, vector control, natural field orientation, speed sensorless drive
- Type of paper
: Ph.D.
Title: Properties of unsymetrical step double lap DC machine
winding
Faculty: Elektrotehnički fakultet Sveučilište Zagreb
Author: GAŠPARAC IVAN
Date of defense: 05/05/93
Language: hrvatski
Number of pages: 218
Summary: Double unsymetrical step armature winding should be used
forlarge DC machines. This type of winding reduces potentialdifferences
among the adjacent commutator bars, but the windingunsymetry and the
unequability od the E.M.F in particular currentpaths and levels of winding
cause voltage pulsations. Voltagepulsations cause commutator's potential
status deterioration andthe equalizing currents cause deterioration of the
commutatingconditions. A method for numerical computation of voltage
amongadjacent commutator bars for defined volume flux densitydistribution
using computer is designed and realized. Theinfluence of armature winding
parameters (number of slots forpair of poles, number of coils in a slot and
the shortening ofwinding) on the mentioned voltage shape (pulsations)
andmagnitude is explored. The effect of shifting the half of a mainpole
shoe on the reduction of this voltage pulsations isexplored, as well as the
influence of the armature windingparameters on this voltage when the half
of a main pole shoe isshifted. The concept of the voltage-free zone in the
spacebetween poles is introduced. Methodology for determination of
thevoltage-free zone width is developed. Voltage-free zone width fora
single lap winding without shifting a main pole shoe iscompared to the
voltage-free zone width for a double lap windingwith the half of main pole
shoe shifted. Reduction of the mainpole covering required for maintaining
the voltage-free zonewidth is defined and the influence on the machine's
powerreduction is shown. A method for recording the coil voltage andthe
voltage among adjacent commutator bars is designed. Thesevoltages were
recorded on an actual DC machine. A method for thevolume flux density
distribution determination based on therecorded voltage of the shortened
coil is developed. Voltagesamong adjacent commutator bars are calculated
from the estimatedflux density distribution and compared with the ones
recorded onthe machine. Well matching of the calculated and measured
resultsconfirms theoretical assumptions, numerical calculation methodsand
estimation procedures. Procedure for armature windingparameters selection
and for the main pole shoe shaping duringthe construction of the large DC
machine is obtained.
Keywords: DC machine, unsymetrical double lap winding, voltage among commutator bars, voltage pulsations, pole shoe, voltage recording, pole covering, voltage-free zone
- Type of paper
: Ph.D.
Title: Investigation of the commutation process in a DC machine
through experiment and simulation
Faculty: Elektrotehnički fakultet Sveučilište Zagreb
Author: ŠIMUNIĆ ZORAN
Date of defense: 05/29/91
Language: hrvatski
Number of pages: 148
Summary: Characteristic phenomena due to the real commutation
process in aDC machine are presented, based on experimental
investigation.Main theoretical claims are synthetized for the establishment
ofa mathematical model. Experimental and theoretical reseachincludes:
characteristics of the slide contact between brush andcommutator sector,
parameters of the commutatin coil inductance,inflence of the commutation
process on magnetic field andmotional e.m.f. distribution in a commutating
coil andestavlishment of a mathematical model for the simulation
ofcommutation process.
Main characteristics of a brush-sector slide contact in thecommutation
process are investigated and described: formation ofelectric contact in the
begenning of the commutation process,characteristics of steady state
potential drop vs. currentdensity and dynamic characteristics in the case
of a high currentdesity increase level. The quality and contours of
commutatorpatina inflence the shortening of the commutation process.
Themethod of computing the electric active surface in slide contactis
defined, based on the geometry of the patina contours andbrush surface
contours.
The investigation of the methods of determining the sparlesscommutatio
range shows that the best method is the calculation ofthe surface electric
power density in slide contact between brushand sector.
Due to the rapid changes of the amount of current in acommutating coil, the
coil inductance is presented by a complexequivalent circuit, comprising the
influence of eddy-currents incuper and iron. Equivalent circuit parameters
are estimated by anew method of analysis of the current and voltage amounts
in atransient state.
The method of determining the armature winding m.m.f. andmotional e.m.f.
distribution in a commutating coil in thecommutating zone due to real
commutation process is described.
The mathematical model for simulating the commutation process isestablished
for a six-pole DC machine with wave winding. This isthe base for further
development of the mathematical model forany kind DC machine. Comparison of
the results of the experimentand simulation shows a good coincidence, so
that the mathematicalmodel and the main theoretical claims are verified.
- Type of paper
: Ph.D.
Title:
Faculty: Elektrotehnički fakultet Sveučilište Zagreb
Author: MILKOVIĆ MATEO
Date of defense: 12/21/92
Language: hrvatski
Number of pages: 153
Summary: The choice of correct brush grade and type for a
specificcommutating machine depends on many brush properties andparameters,
but the coefficient of friction is regarded as theone of particular
importance; the friction occurs when a brushslides over the rotating
commutator bars. Therefore, a greatattention is paid to its value
determination (due to losses andheating up of the parts of the commutatin
assembly). It is alsovaluable when accounting for the changes taking place
in thecontact brush-commutator.
The conventional methods measure the coefficient of friction ofbrush
depending on the material grade, sliding contact surface,environment,
peripheral speed, brush pressure and partially oncurrent density and
temperature. This work describes researchesin the field of the performance
principles of the coefficient offriction of brush at pulsating currents.
All tests wewe carried on electrographite brushes of differentgrade
(material compositions) which are, because of theircommutation properties,
mostly used on real commutators. Thetests were carred in a usual way
(according to IECrecommendation), on the model machine, so called
short-circuitedcommutator with one or two brushes, not on a real commutator
withcoil.
Contrary to conventional methods, which make possible to measurethe static
coefficient of friction indirectly by measurement ofthe tangential forces
acting on the brush, new methods have beendeveloped and set. They make it
possible to measure static anddynamic coefficient of friction. The
experiments proved theadvantages of the method called "resistance bridge"
compared tothe method "electrical balance". It makes it possible to
measuredirectly static and dynamic coefficient of friction.
The method "resistance bridge" was used to find out what are thedrop in the
value of the coefficient of friction of brushrelating to the type and the
value of the current supplied, andto determine to what extend does the
coefficient of frictiondepend on the basic materia grade (composition). The
methodologyfor measurement of static and dynamic coefficient of friction
ofbrush at pulsating current was also established.
According to the test results and their analysis, a mathematicalmodel for
the coefficient of friction of brush has been set outfor the test assembly
consisting of brush and short-circuitedcommutator. According to the values,
calculated and measured, ofthe static coefficient of friction of brush it
can be conclutedthat the static mathematic model is well-deffined.
Consideringthe complexity of mechanical, electrical and
physical-chemicalprocesses that take place in the contact brush-commutator,
thesimulating results obtained by the dynamic mathematical modelgave good
results. However, it should be noted that it ispractically impossible to
give a full mathematical description ofthe dynamic of the coefficient of
friction od brush.
The drop in the value of the coefficient of friction of brushwhich differs
according to the type of the current, as set bythis work, is valuable for
determining the commutator losses on aDC machines supplied by pulsating
current from differentconverter connections.
- Type of paper
: Ph.D.
Title:
Faculty: Fakultet elektrotehnike i računarstva Sveulilište Zagreb
Author: ZDENKOVIĆ JOSIP
Date of defense: 10/10/95
Language: hrvatski
Number of pages: 137
Summary: A speed sensorless vector controlled induction machine
drive is proposed. The control structure may be classified as indirect
vector control structure without speed sensor and with acting on the stator
voltage vector. The torque control is based on proportional relationship
between rotor flux vector slip frequency and torque. The rotor flux vector
slip frequency could not be directly affected, so the stator voltage vector
is used instead. The speed controller output, that represents reference
value of the rotor flux vector slip frequency, is passed through decoupling
circuit defining the reference stator voltage vector. In the decoupling
circuit the stator voltage equation is used in the rotor flux vector
reference frame with presumptions that the rotor flux vector magnitude is
held constant and the total leakage factor considered to be zero. The
machine shaft speed is estimated through mathematical model derived again
from the stator voltage equation in the rotor flux reference frame and
under the same presumptions as for decoupling circuit. The line current
measurement is involved in the control structure for speed estimation
purpose.
Detailed overview of already known methods for speed estimation in
vector controlled induction machine drive together with complete particular
speed sensorless vector control structures are presented too.
In order to prove the efficiency of the proposed speed estimation
method the computer simulations of starting process and stepwise loading
process were done. The case with discrepancies between assumed and actual
machine rotor and stator resistance is simulated too. The control structure
responses are stable. The influence of stator and rotor resistance thermal
changes under steady state and dynamic conditions is evaluated.
The laboratory setup is arranged in order to verify the proposed
control structure behaviour. The laboratory setup consists of: group of
mechanically coupled two induction machines (load machine rated 7.5kW,
investigated machine rated 4kW), two frequency converters, necessary
development and measuring equipment. Frequency converter control unit is
realized with two digital signal processors.
Characteristic nonlinearities in inverter are described and discussed.
The need for compensation of DC link voltage changes, especially during
regenerative operation mode, is experimentally confirmed. The inverter dead
times compensation algorithm is applied for smoothing undesired shaft speed
oscillation under small load condition and for increasing of fundamental
voltage harmonic.
In order to evaluate the introduced control structure the drive
torque/speed characteristics under steady state load condition are measured
with machine in three different thermal states: cold, warm and hot.
Evaluation of influence of machine temperature increase on the control
structure behaviour in steady state was performed by setting the machine
parameters in frequency converter control unit to constant values derived
from no load and short circuit machine tests.It is established that the
proposed control structure ensures difference between reference and actual
shaft speed value of ţ1% of rated machine synchronous speed (with load up
to rated load) at speed references values above 1% of rated machine
synchronous speed for machine in cold state, and above 13.3% for machine in
hot state. If it is desired to get the same accuracy of ţ1% with speed
references below 13.3%, the actual values of stator and rotor resistance
should be identified and relevant parameters in control unit adjusted.
The change in the machine saturation state at speed references below
the rated speed can be performed only by change in the control unit
parameters. In the proposed structure the parameter values of the rotor
magnetizing current vector magnitude and the main machine inductance affect
the machine saturation state. Change in this two control unit parameters
that increases machine flux has a positive influence on speed/torque drive
characteristics.
The optimal operation point concerning losses within machine in applied
control structure under steady state constant load condition could be
reached with the help of information on machine input power. For this
purpose the rotor magnetizing current reference should be adjusted so that
minimum input power is achieved.
The stepwise change in speed reference and the stepwise change in
constant load condition are used for the evaluation of behaviour of
introduced control structure under dynamic conditions. Under all test
conditions the line current limiting function is successfully achieved in
spite of the fact that the control structure has no current control. In
stepwise load change test at low speed references the need of additional
voltage vector magnitude correction is observed and realised through
affecting stator resistance or rotor magnetizing vector magnitude
parameters in the control unit. The change in machine thermal state from
cold to hot has no influence on system responses during starting/reversing
and loading processes only if the machine thermal state is identified at
the lowest speed references.
Because the machine parameters are in general unknown, the simple way
of relevant machine parameter identification for proposed control structure
is discussed. The stator resistance is considered to be easily measurable
and all other parameters are calculated from the machine nameplate.
In spite of the fact that the proposed control structure contains only
one controller and that manual parameter adjusting is not difficult, the
simplified speed control loop equivalent is identified. System responses in
small signal operating mode are compared both for the experimentally
adjusted controller parameters and parameters adjusted according too the
symmetrical optimum theory derived from simplified speed control loop. It
is established that parameters derived from simplified speed control loop
ensure precise controller tuning.
Keywords: induction machine, vector control, digital control, digital signal processor, frequency converter, speed control, speed sensorless drive, speed estimation
- Type of paper
: M.A.
Title:
Faculty: Elektrotehnički fakultet Sveučilište Zagreb
Author: KUNJAŠIĆ ĐINO
Date of defense: 05/28/92
Language: hrvatski
Number of pages: 99
Summary: This thesis examines the importance of parametar knowledge
of thefield-oriented induction machine. It reviews the causes
andconsequences of parametar variability during working process ofthe
induction machine and shows the ways for on-line parametricidentification.
It gives the principle and the basic structures of thefield-orientation,
and describes the mathematical model of thefield-oriented induction motor.
The thesis analyzes methods for the rotor flux vektor estimation.One of
those procedures, used in the real frequency converter isthoroughly
analyzed. The causes for the variability of rotorparametars crucial in
rotor flux estimation are described. Theconsequences for discrepasies
between motor's real parameters andparameter in rotor flux estimator are
discussed in simulation andexperimentally. The simplified mathematical
model is built toanalyze the influence of the rotor time constant on the
rotorflux estimation. The same influence is observed on the realfrequency
converter by measurement and simulation. The resultsgained by both methods
match well and they show the need forcontinuous on-line identification of
rotor resistance andinductivity.
The methods for rotor inductivity identification are examinedcritically.
The most frequently used models for the rotor fluxestimation which consider
the variability of the rotorinductivity caused by saturation are stated and
described. Someof the characteristic methods for on-line rotor
resistanceidentification are also presented. Detailed analysis of work
andthe accurancy of one of the identification methods used in theexamined
frequency converter are made by measurement and bysimulation.
- Type of paper
: M.A.
Title:
Faculty: Elektrotehnički fakultet Sveučilište Zagreb
Author: KOVAČIĆ TIHOMIR
Date of defense: 12/21/92
Language: hrvatski
Number of pages: 100
Summary: For dynamic modelling of synchronous generator it is
besidemathematical model also necessary to have parameters. Givenmethod
identify parameters in the time domain on the basis ofarmature and field
current in the sudden three-phases shortcircuit experiment. Identification
method has two steps. In theexperimental part the armature and field
current are recordedwith digital measuring equipment. In the numeric
partmathematical model of synchronous generator and recorded data
areprepared for identification. Parameter identification is done onthe
computer. During identification measured current and currentgiven with the
help of mathematical model are compared. On thebasis of difference between
currents and with numericaloptimization method for several variables
nonlinear functions theparameters are changed. The identification procedure
is finishedwhen there is no differences between measured and
computedcurrent. The given method enable successful
parameteridentification, mathematical model accuracy control and
quickcontrol of parameters computed with any other method.
- Type of paper
: M.A.
Title: Speed control system of the electronically commutated
motor
Faculty: Elektrotehnički fakultet Sveučilište Zagreb
Author: TERZIĆ BOŽO
Date of defense: 03/18/93
Language: hrvatski
Number of pages: 104
Summary: The physical model for speed control of the
esectronicallycommutated motor, with ratings E=118 V, I=15.9 A, M= 8 Nm,
n=2000r/min, has been designed. The mathematical model is given on thebasis
of the synthesis is based on the linear system according tothe modulus and
symetric optimization method. On the basis of themathematicaldrive model,
the computer program is developed tosimulate steady and dynamic mode of
operations. The reliabilityof the mathematical model has been verified by
comparing thesimulation rusults to those obtain by measurement taken on
thelaboratory drive model.
Keywords: electronically commutated motor, mathematical model, speed control, simulation, physical model, losses
- Type of paper
: M.A.
Title: No load synchronous machine by forced oscillations of the
power supply frequency
Faculty: Elektrotehnički fakultet Sveučilište Zagreb
Author: KOVAČEVIĆ ZORAN
Date of defense: 10/04/93
Language: hrvatski
Number of pages: 117
Summary: The synchronous machine connected to the power supply
withoscillating frequency shows oscillation tendencies.
The first variant of such power supply is the generating set DCmachine -
synchronous machine. In order to accomplish greateroscillations of certain
values (armature current, power, speed ofrotation) it is necessary to
achieve the resonance. During thistime the rotational speeds of both
machines are oscillating inphase opposing, and the driving DC machine is
not overloaded.Calculated and measured results are matching well, so
thecorrectness of the mathematical model is confirmed.
The second variant of such power supply is a frequency converterused to
supply power for the examined synchronous machine. Theessential difference
from the first variant is the fact thatvoltage frequency oscillations don't
request oscillations of thepower of the driving DC machine in order to
accelerate or to slowdown the generating set. Oscillation amplitudes of
certain values(armature current, power, speed of rotation) for the
examinedmachine are substantially larger with the same voltageoscillation
frequency. Calculation results could be compared withthe measurement
results when the suitable frequency converterwould be available.
If frequency converters of sufficient power could be obtained,this variant
of oscillation of the synchronous machine could beused to determine thermal
power of large machines. The basicadvantage of this examination method is
the fact that mechanicalconnection between driving and examined machine is
not needed;electrical connection of the examined machine to the
frequencyconverter is sufficient.
Keywords: synchronous machine, electromechanical oscillations, thermal power, mathematical model
- Type of paper
: Mentorship
Title: Properties of unsymetrical step double lap DC machine
winding
Faculty: Elektrotehnički fakultet Sveučilište Zagreb
Mentor: SMOLČIĆ ZLATKO
Date of defense: 05/05/93
Number of pages: 218
Author: Gašparac Ivan
Degree level: Ph.D.
- Type of paper
: Mentorship
Title: Investigation of the commutation process in a DC machine
through experiment and simulation
Faculty: Elektrotehnički fakultet Sveučilište Zagreb
Mentor: WOLF RADENKO
Date of defense: 05/29/91
Number of pages: 148
Author: Šimunić Zoran
Degree level: Ph.D.
- Type of paper
: Mentorship
Title:
Faculty: Elektrotehnički fakultet Sveučilište Zagreb
Mentor: ILIĆ IVAN
Date of defense: 12/21/92
Number of pages: 153
Author: Milković Mateo
Degree level: Ph.D.
- Type of paper
: Mentorship
Title:
Faculty: Elektrotehnički fakultet Sveučilište Zagreb
Mentor: ILIĆ IVAN
Date of defense: 12/21/92
Number of pages: 100
Author: Kovačić Tihomir
Degree level: M.A.
- Type of paper
: Mentorship
Title:
Faculty: Elektrotehnički fakultet Sveučilište Zagreb
Mentor: BAN DRAGO
Date of defense: 05/28/92
Number of pages: 99
Author: Kunjašić Đino
Degree level: M.A.
- Type of paper
: Mentorship
Title: No load synchronous machine by forced oscillations of the
power supply frequency
Faculty: Elektrotehnički fakultet Sveučilište Zagreb
Mentor: WOLF RADENKO
Date of defense: 10/04/93
Number of pages: 117
Author: Kovačević Zoran
Degree level: M.A.
- Type of paper
: Survey/Study
Title:
- Authors:
- Ban, Drago (1914)
Ordering party: HEP
Institution depot: Elektrotehnički fakultet
Year: 1992
Number of pages: 0
Language: hrvatski
- Type of paper
: Survey/Study
Title:
- Authors:
- Ban, Drago (1914)
- Maljković, Zlatko (27746)
- Dizdarević, N.
- Erceg, Gorislav
- Galić, Damjan
- Puzak, Milivoj
Ordering party: HEP
Institution depot: Elektrotehnički fakultet
Year: 1992
Number of pages: 117
Language: hrvatski
- Type of paper
: Survey/Study
Title:
- Authors:
- Ban, Drago (1914)
- Wolf, Radenko (54263)
- Cettolo, Mirko (6721)
- Kovačević, Zoran (81230)
Ordering party: TE
Institution depot: Elektrotehnički fakultet
Year: 1993
Number of pages: 92
Language: hrvatski
- Type of paper
: Survey/Study
Title:
- Authors:
- Ban, Drago (1914)
- Wolf, Radenko (54263)
- Cettolo, Mirko (6721)
- Kovačević, Zoran (81230)
Ordering party: Drvenjača
Institution depot: Elektrotehnički fakultet
Year: 1993
Number of pages: 76
Language: hrvatski
- Type of paper
: Survey/Study
Title:
- Authors:
- Galić, Damjan
- Erceg, Gorislav
- Ban, Drago (1914)
- Padovan, Lukša
- Novak, Davor
Ordering party: HEP
Institution depot: Elektrotehnički fakultet
Year: 1993
Number of pages: 0
Language: hrvatski
- Type of paper
: Survey/Study
Title:
- Authors:
- Ban, Drago (1914)
- Wolf, Radenko (54263)
- Cettolo, Mirko (6721)
- Kovačević, Zoran (81230)
Ordering party: INA Petrokemija
Institution depot: Elektrotehnički fakultet
Year: 1993
Number of pages: 130
Language: hrvatski
- Type of paper
: Survey/Study
Title:
- Authors:
- Ban, Drago (1914)
- Wolf, Radenko (54263)
- Cettolo, Mirko (6721)
- Kovačević, Zoran (81230)
Ordering party: INA Petrokemija
Institution depot: Elektrotehnički fakultet
Number of pages: 60
Language: hrvatski
- Type of paper
: Survey/Study
Title:
- Authors:
- Ban, Drago (1914)
- Wolf, Radenko (54263)
- Cettolo, Mirko (6721)
Ordering party: HEP
Institution depot: Elektrotehnički fakultet
Year: 1993
Number of pages: 0
Language: hrvatski
- Type of paper
: Survey/Study
Title:
- Authors:
- Ban, Drago (1914)
- Wolf, Radenko (54263)
- Kovačević, Zoran (81230)
- Cettolo, Mirko (6721)
Ordering party: Elektrotehnički fakultet
Institution depot: Elektrotehnički fakultet
Year: 1994
Number of pages: 104
Language: hrvatski
- Type of paper
: Survey/Study
Title: Commutator bars position position determination of DC
machine in motion
- Authors:
- Miletić, Marinko
- Cettolo, Mirko (6721)
- Žubrinić, Mladen
- Himelreich, Zvonimir
- Rabuzin, Zdravko (190694)
- Bušić, Krešimir
- Šimunić, Zoran
Ordering party: TUP
Institution depot: Elektrotehnički fakultet
Year: 1991
Number of pages: 125
Language: hrvatski
- Type of paper
: Survey/Study
Title:
- Authors:
- Ilić, Ivan (17001)
- Rabuzin, Zdravko (190694)
- Šimunić, Zoran
Institution depot: Elektrotehnički fakultet
Year: 1992
Number of pages: 26
Language: hrvatski
- Type of paper
: Survey/Study
Title:
- Authors:
- Maljković, Zlatko (27746)
- Smolčić, Zlatko (105403)
- Cettolo, Mirko (6721)
- Rabuzin, Zdravko (190694)
- Šimunić, Zoran
Ordering party: HE Vinodol
Institution depot: Elektrotehnički fakultet
Year: 1992
Number of pages: 20
Language: hrvatski
- Type of paper
: Survey/Study
Title:
- Authors:
- Bušić, Krešimir
- Rabuzin, Zdravko (190694)
- Kunjašić, Đino (153274)
- Kovačić, Tihomir (163003)
- Cettolo, Mirko (6721)
- Šimunić, Zoran
Ordering party: Drvenjača
Institution depot: Elektrotehnički fakultet
Year: 1992
Number of pages: 192
Language: hrvatski
- Type of paper
: Survey/Study
Title:
- Authors:
- Smolčić, Zlatko (105403)
- Gašparac, Ivan (75402)
Institution depot: Elektrotehnički fakultet
Year: 1992
Number of pages: 59
Language: hrvatski
- Type of paper
: Survey/Study
Title:
- Authors:
- Ban, Drago (1914)
- Wolf, Radenko (54263)
- Cettolo, Mirko (6721)
- Kovačević, Zoran (81230)
Ordering party: Koksara
Institution depot: Elektrotehnički fakultet
Year: 1993
Number of pages: 135
Language: hrvatski
