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International Review of Electrical Engineering - Papers
Integrated Optimal Design of Heterogeneous Electrical Energetic Systems using
Multiobjective Genetic Algorithms
by B. Sareni, J. Régnier, X. Roboam
Vol. 1. n. 1, pp. 112-129
Abstract
- This paper explores the use of Multiobjective Genetic algorithms (MOGAs) for
the Integrated Optimal Design (IOD) of complex heterogeneous power systems in
electrical engineering. IOD consists in simultaneously optimizing architecture,
structural characteristics, sizing of the constitutive elements and energy
management in complex systems. An example of IOD is given in the paper through
the case of a traction device for electric vehicles. It is shown that MOGAs lead
on the one hand to the optimization of given objectives for performance
improvement and on the other hand, provide a better understanding of system
behavior through the analysis of Pareto-optimal solutions.
Copyright © 2006 Praise Worthy Prize - All rights reserved
Keywords:
Genetic Algorithms, Multiobjective Optimization, Integrated Optimal Design,
Power Systems, Electric Vehicles.
Transient EM fields
generated by buried conductor
by M. Lefouili, B. Nekhoul, B. Harrat, K. Kerroum, K. El Khamlichi Drissi
Vol. 1. n. 1, pp. 130-136
Abstract
- In this paper, a new computational approach for characterizing the transient
electromagnetic fields generated by buried conductor is proposed. The
theoretical expressions, in the time domain of electromagnetic fields, generated
by an electric dipole immersed in an infinite conductive medium are developed.
For a semi-infinite dissipative medium, the interface soil-air is taken into
account using a modified image theory. The computation results are based on a
general formulation, in time domain, which permits the observation point in air
or soil. The influences of the length and location of feed point of grounding
electrode are analyzed.
Copyright © 2006 Praise Worthy Prize - All rights reserved
Keywords:
Transient, electromagnetic field, hertziens dipoles, grounding system.
Averaged Switch Modeling Including Conduction Losses for PWM Converters
Operating in Discontinuous Capacitor Voltage Mode
by C. M. Ivan, D. Lascu, V. Popescu
Vol.
1. n. 1, pp. 137-143
Abstract
- In this paper, following the averaged switch approach, an averaged model for
the switch network of the pulse width modulated (PWM) dc-dc converters operating
in Discontinuous Capacitor Voltage Mode (DCVM), with conduction losses, is
developed. A possibility of simplifying the model is also presented. The
simplified model is verified through PSpice simulation using the ĆUK and SEPIC
converters.
Copyright © 2006 Praise Worthy Prize - All rights reserved
Keywords:
Averaged switch models, conduction losses, discontinuous capacitor voltage mode.
Feedback control of multilevel NPC PWM rectifier-multilevel NPC inverter Cascade
by F.Bouchafaa, E.M.Berkouk, M.S.Boucherit
Vol.
1. n. 1, pp. 144-153
Abstract
- Voltage source multilevel inverters have become very attractive for power
industries in power electronics applications during last years. The main
purposes that have led to the development of the studies about multilevel
inverters are the generation of output voltage signals with low harmonic
distortion; the reduction of switching frequency. A serious constraint in a
multilevel inverter is the capacitor voltage-balancing problem. The unbalances
of different DC voltage sources of nine-level neutral point clamping (NPC)
voltage source inverter (VSI) constitute the major limitation for the use of
this new power converter. In order to stabilize these DC voltages, we propose in
this paper to study the cascade constituted by three phases nine-level PWM
rectifier-filter-nine-level NPC voltage source inverter (VSI)-PMSM. In the first
part, the authors present a topology of nine-level NPC VSI, and then they
propose a model of this converter and an optimal PWM strategy to control it
using eight bipolar carriers. The characteristics of this strategy are studied
and performances of the drive of the PMSM fed by this inverter are presented
too. Then in the second part, we study a new high voltage cascade nine-level PWM
current rectifier-filtre-nine-level NPC VSI-PMSM. This study shows particularly
problem of stability of DC voltages of the inverter and its consequence on the
performances of the PMSM speed control. In the last part of this paper, the
authors study the stability problem of the input DC voltages of the inverter. To
remedy to this problem, the authors propose a solution which uses a feedback
control for this cascade. This study allows finding a solution for the
instability problem of the input DC voltages of the inverter. The results
obtained with this solution confirm the good performances of the proposed
solution. This study shows the effect of the stability of the DC voltages on the
PMSM performances. The results obtained are full of promise to use the inverter
in high voltage and great power applications as electrical traction.
Copyright © 2006 Praise Worthy Prize - All rights reserved
Keywords:
Clamping Bridge, Linear feedback control, Multilevel inverter, Multilevel
rectifier, Power factor, PWM strategies.
by N. Boudjerda, M. Melit, B. Nekhoul, K. El Khamlichi Drissi, K. Kerroum
Vol.
1. n. 1, pp. 154-161
Abstract
- It’s proposed a dual randomization of Hybrid Space Vector Modulation (HSVM)
for a full bridge three phase inverter. Both of the switching frequency and the
pulse position are simultaneously randomized. A unified principle of switching
functions generation based on a random triangular carrier is first proposed.
Then, by use of the switching functions, a general analytical model of Power
Spectral Density (PSD) is established for both of output phase to ground voltage
and phase to phase voltage. PSD analysis shows that the proposed dual randomized
modulation scheme allows obtaining the best spread shape comparatively to simple
randomization schemes.
Copyright © 2006 Praise Worthy Prize - All rights reserved
Keywords:
Three-phase inverter, hybrid space vector modulation, dual randomization, power
spectral density, switching function.
DC Source for Arc Welding with Soft-Switching Current-Mode Controlled DC-DC
Converter
by J. Dudrik, P. Bauer
Vol.
1. n. 1, pp. 162-169
Abstract
- Design of a soft-switching, current-mode controlled dc-dc converter for arc
welding is described in the paper. The arc welder based on switch-mode dc-dc
power supply utilises current-mode control for improving working performance of
the current source. The switching power losses are decreased to minimum using
non dissipative turn-off snubber. The operation and performance of the proposed
dc current source was verified on the 3 kW laboratory model of the welder. High
efficiency up to 90% is achieved at nominal current of 120A.
Copyright © 2006 Praise Worthy Prize - All rights reserved
Keywords:
Current Mode Control, DC-DC Power Conversion, Snubber, Welding.
Reliability Focused and Market Driven Growth of Wind Power in Electric Power
Systems
by R. Karki
Vol.
1. n. 1, pp. 170-177
Abstract
- Electric power generation from renewable sources has received considerable
attention due to environmental concerns. Recent technological developments in
wind turbines have resulted in large scale applications in power systems. The
rapid growth of wind power has been backed by different forms of financial
incentives throughout the world. Long-term growth of wind power should, however,
be driven by sustainable market mechanisms. Environmental benefits can be used
to the advantage of the renewables to compete with the less costly conventional
power sources. Assigning monetary value to the environmental benefits and
specifying targets for their growth have been recognized as a potential
solution. This paper presents a probabilistic method to evaluate the renewable
energy credit and its impact on wind penetration and adequacy of power
generating systems. The technique incorporates reliability and economic analyses
and is applied to published test systems to illustrate the results and their
influence on key system variables. The paper provides useful information to
system planners and policy makers of wind power generation.
Copyright © 2006 Praise Worthy Prize - All rights reserved
Keywords:
Power system reliability, Monte Carlo simulation, renewable energy credit, wind
power.
Distributed Generation Overview: Current Status and Challenges
by V. Van Thong, R. Belmans
Vol.
1. n. 1, pp. 178-189
Abstract
- An overview of the present status of distributed generation and its
development is given. Different DG technologies are briefly discussed with their
advantages and disadvantages. General impact of DG on technical, economical and
environmental aspects is discussed. Barriers discouraging DG development and
integration are mentioned as well.
Copyright © 2006 Praise Worthy Prize - All rights reserved
Keywords:
Distributed Generation, Renewable Energy, Technical Impact, Interconnection
Standard.
Power System Reinforcing for Blackout Prevention by a Multi-Objective Optimal
Placement of FACTS Devices
by D. Radu, Y. Bésanger, E. Zamaï, W. Lu
Vol.
1. n. 1, pp. 190-201
Abstract
- Actual interconnected power transmission networks are complex systems that are
commonly run near their operational limits due to a large gap between
electricity demand and generation and from an inadequate transmission capacity
of interconnection lines. In such systems, major cascading disturbances or
blackouts have become too common occurrences. This paper proposes a method to
reinforce the power systems by insertion of FACTS (Flexible Alternating Current
Transmission System) devices, which are optimal placed in order to eliminate the
dangerous contingencies and to prevent by this way the apparition of blackout if
outages occurs. The FACTS devices are optimal placed in order to maximize the
power system security keeping minimal FACTS investment costs. Hence, a
multi-objective genetic algorithm is used to characterize the Pareto Optimal
Frontier (non-dominated solutions) and to provide to Decision Makers and
engineers insightful information about the trade-offs to be made. For these
proposals, we developed a hybrid software in MatlabTM which uses the
EUROSTAGTM software for load flow calculations. The proposed procedures are
successfully tested on an IEEE 14-bus and on an IEEE 30-bus power systems.
Copyright © 2006 Praise Worthy Prize - All rights reserved
Keywords:
Blackout, contingency ranking, FACTS, multi-objective genetic algorithms,
optimal location.
Design of a New Nonlinear Observer of Power Synchronous Generator Damper
Currents
by M. Ouassaid, M. Cherkaoui
Vol.
1. n. 1, pp. 202-208
Abstract
- In this paper, a new nonlinear observer for the synchronous machine damper
currents is developed. The observer design is based on the theory of Lyapunov of
nonlinear systems. The stability of the proposed observer is shown to be
Globally Exponentially Stable (GES) in the context of Lyapunov theory. The paper
also describes how to design the observer gain, and includes computer simulation
results to demonstrate the effectiveness of the proposed observer.
Copyright © 2006 Praise Worthy Prize - All rights reserved
Keywords:
Damper currents, Lyapunov stability, nonlinear observer, synchronous generator.
Rotor Resistance and Mutual Inductance Estimation by Extended Complex Kalman
Filter and Spiral Vector Theory of an Induction Motor without
Speed Sensor
by M. Menaa, O. Touhami, R. Ibtiouen, M. Fadel
Vol.
1. n. 1, pp. 209-218
Abstract
- In this paper the authors show that it is possible to estimate the parameters
and the state model of an induction motor by using only two sensors. A new
approach to dynamical modelling and parameters estimation of an induction motor
is developed. The proposed model is based on spiral vector theory. This leads to
a compact mathematical model in complex space which depends on the variables and
the parameters of only one single phase of stator and rotor. This is called
phase segregation method. A new filter is also used in order to estimate the
complex states, parameters and rotor speed of an induction motor. This filter is
a variant of non linear Kalman filter in its complex form “Extended complex
Kalman filter, ECKF”.
Copyright © 2006 Praise Worthy Prize - All rights reserved
Keywords:
AC Machines, Extended Complex Kalman Filter, Estimation, Induction Motors,
Modelling, Phase Segregation Method, Sensorless, Spiral Vector Theory.
Extended Park Model for Torque Ripples Minimization of a Permanent-Magnet
Synchronous Machine
by Y. Ait-gougam, R. Ibtiouen, O. Touhami, J.-P. Louis
Vol.
1. n. 1, pp. 219-228
Abstract
- Sinusoidal motor’s mathematical models are usually obtained using classical
d-q transformation. In this paper, a new inverse modeling for synchronous motors
is presented. This modeling is based on the constant torque curves properties in
the Concordia’s reference frame. It takes into consideration the non-sinusoidal
character of magnetic field distribution, self and mutual inductances with
respect to the angular rotor position. Torque control, in the extended Park
referential, is achieved by two chief methods of current minimization. The first
one uses the optimal current that yields a constant instantaneous torque while
minimizing copper losses and the second uses the sub-optimal current based on
mean torque calculation. In this case, current reference and torque reference
are expressed by polynomial function after normalization. The functions
optimizing the mean torque are easy to implement and minimize both copper losses
and torque ripples. Simulation and experimental results on DSP-based test bed
are presented and shows the efficiency of the proposed method.
Copyright © 2006 Praise Worthy Prize - All rights reserved
Keywords:
Synchronous Machines, Permanent Magnets, Inverse Modeling, Torque Ripples,
Optimization.
On the Reliable Operation of Power Silicon Rectifier Diodes above the Specified
Maximum Permissible Junction Temperature
by V. V. N. Obreja
Vol.
1. n. 1, pp. 229-233
Abstract
- Typical reverse electrical characteristics for commercial rectifier diodes
from room temperature up to high junction temperature of 250 - 300°C are
presented A spreading of the reverse current values ranging an order of
magnitude is possible for standard recovery diodes. This is caused by
fluctuations in the level of the junction edge current component resulted in the
manufacturing process. The maximum permissible temperature specified in the data
sheets has to match the manufactured samples with excessive high reverse current
and for this reason is limited to 175 -200°C. Selected samples with
significantly reduced reverse current on behalf of the edge current can operate
reliably up to 250°C. The maximum permissible junction temperature for high
voltage switching diodes can be extended from 125 -150°C to 175 -200°C if the
level of reverse current is reduced by better control on the
generation-recombination centers from the junction base.
Copyright © 2006 Praise Worthy Prize - All rights reserved
Keywords:
PN junction, reverse current, reverse recovery time, electrical characteristic,
thermal.
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