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Multifrequency
Operation Technique Using Slot
Loaded Gap-Coupled Microstrip Antenna --
R
B Konda, G M Pushpanjali, S N Mulgi, S K Satnoor and P V Hunagund
A
novel design of U-slot Gap-coupled Rectangular Microstrip
array Antenna (USGRMSA) using corporate feed arrangement for
triple-band operation is proposed. This antenna offers triple
bands at 8.24, 8.86 and 11.02 GHz of frequencies.The overall
impedance bandwidth is found to be 8.8%. The effect of change
in impedance bandwidth and gain is studied experimentally
by replacing U-slot with V and H-slots in the parasitic element
of USGRMSA. The H-slot antenna gives maximum impedance bandwidth
and gain among the proposed antennas. Most importantly, this
antenna also shows sum and difference radiation pattern in
its operating bands. The design concepts of the proposed antennas
are described and experimental results are discussed.
©
2008 The Icfai University Press. All Rights Reserved.
Design
and Implementation of Robust Controller Through H¥
Approach -- Surya Prakash
Singh and Ramesh Kumar Tripathi
The
control theory has achieved much in the last few decades,
resulting in many sophisticated control schemes. Among them
Robust Controller is the most popular type of controller used
in industries. This is because Robust Controller works in
the presence of uncertainties and disturbances. The goal of
Robust Controller is to design a controller which gives satisfactory
performance in the presence of uncertainties and disturbances.
There are many methods for Robust Controller design. But here
H¥ method for Robust Controller design is
considered. The H¥ method is applied with
disturbance and noise type uncertainty, additive type uncertainty,
and multiplicative type uncertainty. The H¥
method gives better results in all situations.
©
2008 The Icfai University Press. All Rights Reserved.
Illustrative
Investigations on PMD Induced Penalties in 80 Gbps Optical
Transmission Link -- Neeru Malhotra
and Manoj Kumar
Polarization
Mode Dispersion (PMD) in optical fibers and components can
be a limiting impairment in high-speed, long-haul transmission
link. In this paper, we have reported investigations on PMD
induced penalties in 40 Gbps and higher bit rate optical transmission
link and we obtained the results for DGD, BER, Q2
(dB) for different values of the PMD coefficient and different
random seeds using computer simulation. The measurements of
these performance characteristics are also supported by signal
plot(s), eye diagram, DGD, Stokes parameters on Poincare Sphere
and BER/ Q2 (dB) values. Here, we have illustrated
that PMD-induced differential group delay degrades system
performance with penalties more severe at higher bit rates,
i.e., 40 Gbps and above and higher PMD coefficients in fibers.
©
2008 The Icfai University Press. All Rights Reserved.
Speed
Estimation of Series-Connected Five-Phase Two-Motor Drive
System Using Open-Loop Estimator --
M Rizwan Khan and Atif Iqbal
Multi-phase
machines can be used in variable speed drives. The applications
are electric ship propulsion, more-electric aircraft and traction
applications, and also electric and hybrid electric vehicles.
The multi-phase machines enable independent control of a few
number of machines that are connected in series in a particular
manner, and the supply is fed from a single Voltage Source
Inverter (VSI). The idea was first implemented for a five-phase
series-connected two-motor drive system, but is now applicable
to any number of phases more than or equal to five-phase.
The number of series-connected machines is a function of the
phase number of VSI. The theoretical and simulation studies
have already been reported for a number of multi-phase multi-motor
drive configurations of series-connection type. Variable speed
induction motor drives without mechanical speed sensors at
the motor shaft have the attractions of low cost and high
reliability. To replace the sensor, information of the rotor
speed is extracted from measured stator currents and voltages
at motor terminals. Open-loop estimators or closed-loop observers
are used for this purpose. They differ with respect to accuracy,
robustness, and sensitivity against model parameter variations.
This paper analyzes the operation of an open-loop estimator
based sensorless control of vector controlled series-connected
two-motor five-phase drive system with current control in
the stationary reference frame. Results obtained with fixed-voltage
and fixed-frequency supply fed and hysteresis current control
are presented for various operating conditions on the basis
of simulation results. The purpose of this paper is to report,
for the first time, the simulation results on a sensorless
control of a five-phase two-motor series-connected drive system.
The operating principle is given first, followed by the description
of the sensorless technique.
©
2008 The Icfai University Press. All Rights Reserved.
Operation
of Multilevel Inverter Using Fuzzy
Logic Controller -- Mithun
M Bhaskar and R Gnanadass
This
paper describes the design of a novel Fuzzy Logic Controller
(FLC) with conventional controllers for multilevel inverter.
Multilevel inverters find much use in the Industrial and Power
system application like electric vehicles and in Flexible
AC Transmission System (FACTS) devices. The conventional control
methods are mainly restricted to the direct and indirect control
of the inverter. The proposed fuzzy logic controller shows
improved functionalities in the simulative experimental studies
conducted in the lab. A multilevel inverter is controlled
by varying the modulation index of the inverter by keeping
the DC link voltage constant. The Cascaded H Bridge multilevel
inverter topology is selected after a thorough evaluation
of the advantages of it and a nine-level multilevel inverter
is designed as the test system. The Fuzzy Associative Memory
(FAM) table is derived after a thorough research of the characteristics
and compared with the conventional controller for harmonic
disturbance, voltage profile and other system parameters.
The new controller is found to be faster to the disturbances
and has lowest settling time in the comparative study of controllers.
©
2008 The Icfai University Press. All Rights Reserved.
Artificial
Neural Network Based Electricity Price Forecasting in Ontario
Power System Using Particle Swarm Optimization Method
-- Sanjeev Kumar Aggarwal, L M
Saini and Ashwani Kumar
In
recent years, regulated or state-owned monopoly electricity
markets have been deregulated. The price of electricity in
deregulated markets is very volatile and therefore, for financial
risk management, one day ahead electricity price forecasting
has become important for all the participants. In this paper,
a Particle Swarm Optimization (PSO) based Artificial Neural
Network (ANN) model to forecast hourly price profile in Ontario's
Electric Power System has been presented. The PSO algorithm
offers the capability of converging towards the global minimum
point of a complex error surface. Twenty-four separate Feed-Forward
Neural Networks (FFNNs) have been used for modeling 24 trading
intervals of the day. This allows one to take advantage of
the homogeneity of these 24 time series. Forecasting performance
of the proposed model has been compared with: (i) a heuristic
technique; and (ii) a simulation based model used by the Independent
Electricity System Operator (IESO) of Ontario. Forecasting
results show that PSO based NN model is more accurate than
the other models and can be used by the participants for bidding
preparation and optimizing the load schedules, as it predicts
price well before closing of window for submission of bids.
©
2008 The Icfai University Press. All Rights Reserved.
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