COLLOQUIUM on Variable Speed Drives
The Development of an Educational package
for Variable Speed Drives
M E Tshwele M D McCulloch C F Landy
Electrical Power Research Group
Dept Electrical Engineering
University of Witwatersrand, PO WITS 2050
ABSTRACT
The purpose of this research is to develop an
educational package for variable speed drives. The pmgram
is PC based and can therefore run on any IBM PC or
compatibles. It is intended to assist students in learning how
variable speed drive circuits work.
Simulation studies are performed on selected
pre-constructed circuits and vital information like speed,
torque, voltage etc. can be obtained. This program is based
on an existing package called CASED. CASED was
developed for the dynamic and steady state simulation of
electrical drives.
The pre-constructed circuits include a number of
convertor topologies. The list includes single phase, three
phase half wave and six pulse convertor circuits. All the
above are a.c. to d.c. convertors. The package also includes
single and three phase inverters and special application
circuits like twelve puke convertors.
ENERGY SAVINGS WITH VARIABLE SPEED DRIVES
K M Pauwels
Energy auditor, Laborelec, Industrial Applications,
Belgium
SUMMARY
Ths paper focuses on the economic benefits that can be
obtained by replacing mechanical flow control of
pumps and fans with variable speed drives. I
Firstly, different topologies of variable speed drives are
discussed: rectifier topologies (thyristor, IGBT) as well
as the control of invertors with Pulse Width
Modulation. A short overview of the advantages for the
different topologies is given.
The most important restrictions are also mentioned.
The core of the paper consists of three case studies,
which are taken from our energy consulting experience
in Belgian industry.
Vector Control and Fuzzy Logic Control of Doubly Fed
Variable Speed Drives with DSP Implementation
Yifan Tang, Member, IEEE Longya Xu, Senior MemberJEEE
The Ohio State University
Department of Electrical Engineering
2015 Neil Avenue
Columbus, OH 43210
Abstract- Field orientation control and fuzzy logic control
are designed for variable speed drive systems with a
doubly fed machine in slip power recovery configuration.
Laboratory implementation with a general purpose DSP
(digital signal processing) system is described and experimental
results are given. High performance potential of a
slip power recovery system is realized with these advanced
controls, while flexible reactive power control becomes possible,
and compared to the ordinary variable speed drives
with singly fed induction machine, power converter rating
is reduced.
Key Words: Vector Control, Fuzzy Logic Control, Slip
Power Recovery System, Doubly Fed Machines, Variable
Speed Drive, Digital Signal Processing
Test Bed System to Evaluate the Efficiency of Variable Speed
Drives Under Varying Load Conditions
M L Walker, Student Member, IEEE , G Diana*, Member, IEEE
Department of Electrical Engineering, University of Natal, Dalbridge, 404 1, Durban
e-mail : Walkerm 1 @,eng . und . ac. za , * Gdiana(ii,eng.und. ac. zg
Abstract - This paper describes the hardware
requirements for a user friendly, easy to use test bed
system to evaluate the efficiency of Variable Speed
Drives under variable load conditions. The test bed
will allow Variable Speed Drives to be loaded with any
desired load characteristic to enable measurement and
comparison of the savings that can be achieved when
replacing fixed speed drives with variable speed drives.
.INDUCTION MOTOR.IMPROVEMENT FOR ENERGY SAVING:
. TECHNOLOGIES. : . .
. OlgaCMuravleva, Oleg Muravlev -
Tomsk Polytechnic University :
30 Lenin Avenue, Tomsk, Russia, 634050
Te1.+7 3822 415453.‘
E-majl: mop@tpu.ru, moo@isc.tpu.edu.ru
Abstract
Recent attention has been focused on energy saving problems in Russia, these latter being of
prime consideration. Nowadays our society has come to realize that this factor of economic
life is a decisive one on the way of achieving higher indices of country economic development.
Possessing power consuming of manufacturing several times greater than in the developed
Countries of the world and being excessively wasteful when using thermal and electric energy
one can’t achieve high level of,energy saving.
The purpose of the given paper is to show the possibility of actual energy saving by induction
motor improvement for a variable speed drive.
Power electronics, microprocessor techniques and electrical machines are integral parts of a
modern drive. As for the marked changes of the first two components of the drive they are
being widely discussed in the press but the problem of electrical machines improvement is
kept in the shade.
Modern induction motors should meet the variable speed drive requirements.
Individualization of orders and customer requirements to induction motors allows electro
technical industry to steadily raise the rate of production under the~conditionso f market
economy. Taking into consideration marked output of different rating induction motors and
their primary role in electric energy conversion into mechanical one even slight
improvements of engineering economical indices will pave the way for producing an effect.
However, a variable speed drive based on induction motors is slowly introduced.’
One should consider induction motor improvement combined with the development of
power electronics, systems of control and emergency protection as a final result - effective
energy saving in all the spheres of their usage.
Robust Control Design through Experimental Load Identification
for Variable Speed Drives
Nnamdi Okaeme, Pericle Zanchetta and Mark Sumner
School of Electrical and Electronics Engineering
University of Nottingham, University Park
Nottingham, NG7 2RD
UNITED KINGDOM
eexno@nottingham.ac.uk, Pericle.Zanchetta@nottingham.ac.uk, Mark.Sumner@nottingham.ac.uk
Abstract – A robust method for speed control design in variable
speed drives based on experimental plant model identification is
presented in this paper. Genetic Algorithms are employed for
both experimentally identifying the nominal mechanical system
parameters and to optimize suitable controllers on an accurate
simulation of the experimental prototype using the estimated
plant parameters and with a robustness constraint based on the
same identified mechanical system model. Structure and
parameters of robust speed controllers have been designed for a
permanent magnet DC variable speed drive subject to variable
mechanical loads. Experimental tests are presented to validate
the proposed design procedure. The method provides a fully
automated commissioning procedure for servo and high
performance drives and offers significant improvements to
current industrial drive systems.