Iranian Journal of Electrical & Electronic Engineering
http://ijeee.iust.ac.ir
Iranian Journal of Electrical and Electronic Engineering - Journal articles for year 2010, Volume 6, Number 2Yektaweb Collection - http://www.yektaweb.comen2010/6/11Application of Neural Space Mapping for Modeling Ballistic Carbon Nanotube Transistors
http://ijeee.iust.ac.ir/browse.php?a_id=289&sid=1&slc_lang=en
In this paper, using the neural space mapping (NSM) concept, we present a
SPICE-compatible modeling technique to modify the conventional MOSFET equations, to
be suitable for ballistic carbon nanotube transistors (CNTTs). We used the NSM concept in
order to correct conventional MOSFET equations so that they could be used for carbon
nanotube transistors. To demonstrate the accuracy of our model, we have compared our
results with those obtained by using open-source software known as FETToy. This
comparison shows that the RMS errors in our calculated IDS, under various conditions, are
smaller than the RMS errors in IDS values calculated by the existing analytical models
published by others.K. SaghafiDesign of a Resonant Suspended Gate MOSFET with Retrograde Channel Doping
http://ijeee.iust.ac.ir/browse.php?a_id=290&sid=1&slc_lang=en
High Q frequency reference devices are essential components in many Integrated
circuits. This paper will focus on the Resonant Suspended Gate (RSG) MOSFET. The gate
in this structure has been designed to resonate at 38.4MHz. The MOSFET in this device
has a retrograde channel to achieve high output current. For this purpose, abrupt retrograde
channel and Gaussian retrograde channels have been investigated.M. H. RefanImplementation and Critical Investigation on Modulation Schemes of Three Phase Impedance Source Inverter
http://ijeee.iust.ac.ir/browse.php?a_id=291&sid=1&slc_lang=en
New control circuits and algorithms are frequently proposed to control the
impedance (Z) source inverter in efficient way with added benefits. As a result, several
modified control techniques have been proposed in recent years. Although these techniques
are clearly superior to the simple boost control method which was initially proposed along
with the Z-source inverter (ZSI), little or conflicting data is available about their merits
relating to each other. In this paper, it is shown how the shoot-through periods are inserted
in the switching waveforms of the power switches and the performances of them are
analyzed based on the operation of ZSI. Simple boost control, maximum boost control,
constant boost control and space vector modulation based control methods given in the
literature has been illustrated with their control characteristics. A critical investigation on
ripples of the impedance source elements, output voltage controllability, output harmonic
profile, transient response of the voltage across the impedance source capacitor and voltage
stress ratio etc has been presented with the simulation results. The simulation results are
experimentally verified in the laboratory with digital signal processors (DSP). DSP coding
for the above all control techniques has been generated by interfacing Matlab/Simulink
with DSP C6000 tool box and signal processing block set.S. ThangaprakashTransmission Cost Allocation in Restructured Power Systems Based on Nodal Pricing Approach by Controlling the Marginal Prices
http://ijeee.iust.ac.ir/browse.php?a_id=292&sid=1&slc_lang=en
This paper presents a method to allocate the transmission network costs to users
based on nodal pricing approach by regulating the nodal prices from the marginal point to
the new point. Transmission nodal pricing based on marginal prices is not able to produce
enough revenue to recover the total transmission network costs. However, according to the
previous studies in this context, this method recovers only a portion of transmission costs.
To solve this problem, in this paper a method is presented in which by considering the
direction and amount of injected power in each node the marginal price is regulated to the
new price, in such a way as the nodal pricing can recover the total transmission network
costs. Also the proposed method is able to control the cost splitting between loads and
generators in accordance with the pre-specified ratio. The proposed method is implemented
on both IEEE 24-bus and 118-bus test systems and the obtained results are reported.R. GhaziReliability Model of Power Transformer with ONAN Cooling
http://ijeee.iust.ac.ir/browse.php?a_id=293&sid=1&slc_lang=en
Reliability of a power system is considerably influenced by its equipments.
Power transformers are one of the most critical and expensive equipments of a power
system and their proper functions are vital for the substations and utilities. Therefore,
reliability model of power transformer is very important in the risk assessment of the
engineering systems. This model shows the characteristics and functions of a transformer in
the power system. In this paper the reliability model of the power transformer with ONAN
cooling is obtained. The transformer is classified into two subsystems. Reliability model of
each subsystem is achieved. Markov process representation and the frequency/ duration
approach are employed to obtain a complete reliability model of the subsystems. By
combining these models reliability model of power transformer is obtained. The reliability
model associated with the transformer is then proposed combining the models of
subsystems. The proposed model contains five states. To make the model more applicable,
the 5-state model is alleviated to a 3-state one. Numerical analysis and sensitivity analysis
relevant to the proposed reliability model are performed for evaluating the numerical values
of the model parameters and the impact of different components on the reliability of the
model.M. SefidgaranImproved Direct Torque Control for Induction Machine Drives Based on Fuzzy Sector Theory
http://ijeee.iust.ac.ir/browse.php?a_id=294&sid=1&slc_lang=en
Here, a new fuzzy direct torque control algorithm for induction motors is
proposed. As in the classical direct torque control, the inverter gate control signals directly
come from the optimum switching voltage vector look-up table, the best voltage space
vector selection is a key factor to obtain minimum torque and flux ripples. In the proposed
approach, the best voltage space vector is selected using a new fuzzy method. A simulation
model is built up and the torque and flux ripples of basic direct torque control and the
proposed method are compared. The simulation results show that the torque and flux
ripples are significantly decreased and in addition, the switching frequency can be fixed.M. M. RezaeiDetermination of Electric Field at Inception Based upon Current-Voltage Characteristics of AC Corona in Rod-Plane Gaps
http://ijeee.iust.ac.ir/browse.php?a_id=295&sid=1&slc_lang=en
This paper deals with the measurement of AC corona inception voltage, Vincp, at
the tip of a rod electrode using a hemispherically-capped rod-plane electrode configuration
for various rod radii with a short air gap. Effects of atmospheric pressure and temperature
variation on Vincp are investigated experimentally. An empirical equation for the field form
factors of the hemispherically capped rod-plane electrodes is proposed with its range of
applicability. The obtained results are analyzed to derive a more accurate analytical
equation for the calculation of the electric field at corona inception voltage, Eincp, and the
average of electric field distribution, EmeanH. Javadi