Showing 14 results for Arab
Lesani, Darabi, Nasiri Gheidari, Tootoonchian,
Volume 2, Issue 1 (January 2006)
Abstract
In this paper, a new field oriented control scheme with maximum torque for permanent magnet hysteresis synchronous (PMHS) motor has been presented. Vector control method provides significant improvement to the dynamic performance of ac motors but in this method d- axis current is controlled such as the ratio of motor torque to motor current is a maximum, then the dynamic performance will be very fast. Furthermore, d and q axis currents are limited such as stator winding currents remain in the allowed range. Feedback method is used for the decoupling the torque-current component from the fluxcurrent component so these two components can be independently controlled. Simulation results for the motor are given and test results validate the theoretical performances.
D. Arab-Khaburi, F. Tootoonchian, Z. Nasiri-Gheidari,
Volume 3, Issue 1 (April 2007)
Abstract
Because of temperature independence, high resolution and noiseless outputs,
brushless resolvers are widely used in high precision control systems. In this paper, at first
dynamic performance characteristics of brushless resolver, considering parameters
identification are presented. Then a mathematical model based on d-q axis theory is given.
This model can be used for studying the dynamic behavior of the resolver and steady state
model is obtained by using dynamic model. The main object of this paper is to present an
approach to identify electrical and mechanical parameters of a brushless resolver based on
DC charge excitation and weight, pulley and belt method, respectively. Finally, the model
of resolver based on the obtained parameters is simulated. Experimental results approve the
validity of proposed method.
D. Arab-Khaburi, F. Tootoonchian, Z. Nasiri-Gheidari,
Volume 4, Issue 3 (July 2008)
Abstract
A mathematical model based on d-q axis theory and dynamic performance
characteristic of brushless resolvers is discussed in this paper. The impact of rotor
eccentricity on the accuracy of position in precise applications is investigated. In particular,
the model takes the stator currents of brushless resolver into account. The proposed model
is used to compute the dynamic and steady state equivalent circuit of resolvers. Finally,
simulation results are presented. The validity and usefulness of the proposed method are
thoroughly verified with experiments.
A. Darabi, T. Ghanbari, M. Rafiei, H. Lesani, M. Sanati-Moghadam,
Volume 4, Issue 4 (October 2008)
Abstract
Hysteresis motors are self starting brushless synchronous motors which are
being used widely due to their interesting features. Accurate modeling of the motors is
crucial to successful investigating the dynamic performance of them. The hysteresis loops
of the material used in the rotor and their influences on the parameters of the equivalent
circuit are necessary to be taken into consideration adequately. It is demonstrated that some
of the equivalent circuit parameters vary significantly with input voltage variation and other
operating conditions. In this paper, a comprehensive analysis of a hysteresis motor in the
start up and steady state regimes are carried out based on a developed d-q model of the
motor with time-varying parameters being updated during the simulation time. The
equivalent circuit of the motor is presented taking into account the major impact of the
input voltage. Simulation results performed in Matlab-Simulink environment prove that the
existing simple models with constant parameters can not predict the motor performance
accurately in particular for variable speed applications. Swings of torque, hunting
phenomenon, improvement of power factor by temporarily increasing the stator voltage and
start up behavior of the hysteresis machine are some important issues which can accurately
be analyzed by the proposed modeling approach.
D. Arab Khaburi, H. Rostami,
Volume 7, Issue 1 (March 2011)
Abstract
This paper presents a method to control both the dc boost and the ac output voltage of Z-source inverter using neural network controllers. The capacitor voltage of Z-source network has been controlled linearly in order to improve the transient response of the dc boost control of the Z-source inverter. The peak value of the line to line ac output voltage is used to control and keep the ac output at its desired value. A modified space vector pulse-width-modulation method is also applied to control the shoot-through duty ratio for boosting dc voltage. This modified method lets the dc voltage stress across the inverter switches be minimized. The neural network control technique is verified by simulation results. The results are compared with that of the traditional PI controller.
D. Arab Khaburi,
Volume 8, Issue 2 (June 2012)
Abstract
This paper presents a comparative study on the Predictive Direct Torque Control
method and the Indirect Space Vector Modulation Direct Torque Control method for a
Doubly-Fed Induction Machine (DFIM) which its rotor is fed by an Indirect Matrix
Converter (IMC). In Conventional DTC technique, good transient and steady-state
performances are achieved but it presents a non constant switching frequency behavior and
non desirable torque ripples. However, in this paper by using the proposed methods, a fixed
switching frequency is obtained. In this model Doubly-Fed Induction Machine is connected
to the grid by the stator and the rotor is fed by an Indirect Matrix Converter. Functionally
this converter is very similar to the Direct Matrix Converter, but it has separate line and
load bridges. In the inverter stage, the Predictive method and ISVM method are employed.
In the rectifier stage, in order to reduce losses caused by snubber circuits, the rectifier fourstep
commutation method is employed. A comparative study between the Predictive DTC
and ISVM-DTC is performed by simulating these control systems in
MATLAB/SIMULINK software environments and the obtained results are presented and
verified.
A. Darabi, M. Yousefisefat, M. Nikkhoo,
Volume 10, Issue 1 (March 2014)
Abstract
Quadrature-axis reactance for various reasons comes into account as one of the most important parameters of salient pole synchronous machine. There are several common standard methods for measuring this parameter that also have been explained with some details in the standards, scientific papers and text books. One of these methods is the maximum lagging current test that is done simply at no-load, having a three phase voltage source and applying very low power even for a high power machine. How this experiment is done is described at some references such as the books related to electrical machinery. This paper presents a detail analysis and description of the test and some simulation results regarding the performance of the machine during pole-slipping. It is shown when the reversal field current is increased very slowly, the transient of the pole-slipping commences at load angle equal to 45 degrees or by a better language at 225 instead of zero which is the common opinion of almost all the previously published literatures. In this paper, a realistically developed analysis of the test is presented applying appropriate assumptions. The maximum lagging current test is then simulated applying a small salient pole machine with the rated 31.5 kVA using Matlab/Simulink. Some simulation results are illustrated that prove correctness and validity of the new analysis and the proof described by the present paper.
F. Farabi, M. R. Mosavi, S. Karami,
Volume 11, Issue 2 (June 2015)
Abstract
Impressive development of computer networks has been required precise evaluation of efficiency of these networks for users and especially internet service providers. Considering the extent of these networks, there has been numerous factors affecting their performance and thoroughly investigation of these networks needs evaluation of the effective parameters by using suitable tools. There are several tools to measure network's performance which evaluate and analyze the parameters affecting the performance of the network. D-ITG traffic generator and measuring tool is one of the efficient tools in this field with significant advantages over other tools. One of D-ITG drawbacks is the need to determine input parameters by user in which the procedure of determining the input variables would have an important role on the results. So, introducing an automatic method to determine the input parameters considering the characteristics of the network to be tested would be a great improvement in the application of this tool. In this paper, an efficient method has been proposed to determine optimal input variables applying evolutionary algorithms. Then, automatic D-ITG tool operation would be studied. The results indicate that these algorithms effectively determine the optimal input variables which significantly improve the D-ITG application.
M. Mollanezhad Heydarabadi, A. Akbari Foroud,
Volume 12, Issue 4 (December 2016)
Abstract
Current inversion condition leads to incorrect operation of current based directional relay in power system with series compensated device. Application of the intelligent system for fault direction classification has been suggested in this paper. A new current directional protection scheme based on intelligent classifier is proposed for the series compensated line. The proposed classifier uses only half cycle of pre-fault and post fault current samples at relay location to feed the classifier. A lot of forward and backward fault simulations under different system conditions upon a transmission line with a fixed series capacitor are carried out using PSCAD/EMTDC software. The applicability of decision tree (DT), probabilistic neural network (PNN) and support vector machine (SVM) are investigated using simulated data under different system conditions. The performance comparison of the classifiers indicates that the SVM is a best suitable classifier for fault direction discriminating. The backward faults can be accurately distinguished from forward faults even under current inversion without require to detect of the current inversion condition.
S. Heshmatian, D. Arab Khaburi, M. Khosravi, A. Kazemi,
Volume 14, Issue 1 (March 2018)
Abstract
Wind energy is one of the most promising renewable energy resources. Due to instantaneous variations of the wind speed, an appropriate Maximum Power Point Tracking (MPPT) method is necessary for maximizing the captured energy from the wind at different speeds. The most commonly used MPPT algorithms are Tip Speed Ratio (TSR), Power Signal Feedback (PSF), Optimal Torque Control (OTC) and Hill Climbing Search (HCS). Each of these algorithms has some advantages and also some major drawbacks. In this paper, a novel hybrid MPPT algorithm is proposed which modifies the conventional methods in a way that eliminates their drawbacks and yields an improved performance. This proposed algorithm is faster in tracking the maximum power point and provides a more accurate response with lower steady state error. Moreover, it presents a great performance under conditions with intensive wind speed variations. The studied Wind Energy Conversion System (WECS) consists of a Permanent Magnet Synchronous Generator (PMSG) connected to the dc link through a Pulse-Width Modulated (PWM) rectifier. The proposed algorithm and the conventional methods are applied to this WECS and their performances are compared using the simulation results. These results approve the satisfactory performance of the proposed algorithm and its notable advantages over the conventional methods.
S. Mohammad Nejad, H. Arab, N. Ronagh Sheshkelani,
Volume 14, Issue 3 (September 2018)
Abstract
In this paper, after a brief overview on laser warning system (LWS), a new structure for an optical array that is used in its optical subsystem is introduced. According to the laser threats’ wavelengths (0.5 – 1.6 µm) and our desirable field of view (FOV), we used 6 lenses for gathering the incident radiation and then optimized the optical array. Lenses’ radius, their semi diameter, their distance from each other, their thickness and the kind of glass used in them was chosen in which we access a very high transmission coefficient. Also the optical reflection and absorption of the array decreases at the same time. After optimization, the obtained optical transmission in our desirable FOV is up to 82% and the obtained optical reflection and absorption is less than 15%. Total aberration of the incident ray decreased notably and the results showed that this parameter is less than 2µm. The laser spot diameter which is focused on the detector is smaller than 400 µm in the worst case which is the laser radiation with 1.54 µm wavelength and field of 10 degrees. Total track of the array is 66.819 mm and effective focal length and F/# parameter are as small as possible which leads to high quality of the light’s focus on the detector and smaller dimension and lighter weight for the receiver. Using optical devices with such appropriate arrangement and very good optical transmission coefficient, the offered structure has a remarkable signal to noise ratio (SNR) which is up to 160 dB. The receiver’s operation in far distances from laser sources (beyond 15 km) and in hazy conditions and low temperatures is quite suitable as well.
M. El Alaoui, F. Farah, K. El Khadiri, H. Qjidaa, A. Aarab, A. Lakhssassi, A. Tahiri,
Volume 15, Issue 4 (December 2019)
Abstract
In this work, the design and analysis of new Level Shifter with Gate Driver for Li-Ion battery charger is proposed for high speed and low area in 180nm CMOS technology. The new proposed level shifter is used to raise the voltage level and significantly reduces transfer delay 1.3ns (transfer delay of conventional level shifter) to 0.15ns with the same input signal. Also, the level shifter with gate driver achieves a propagation delay of less than 0.25ns and the total area is only 0.05mm2. The proposed level shifter with gate driver was designed, simulated and layouted in Cadence using TSMC 180nm CMOS technology.
H. Zahedi Abdolhadi, Gh. Arab Markadeh, S. Taghipour Boroujeni,
Volume 17, Issue 3 (September 2021)
Abstract
Classical structure of Doubly Fed Induction Generators (DFIGs) is not completely adapted in high-speed regions due to their brushes and slip rings. So in the Cascaded DFIGs (CDFIGs), the rotor windings of a given DFIG are supplied by another wound rotor induction machine leading to a complete brushless structure. This paper presents and compares Sliding Mode Control (SMC) and Terminal Sliding Mode Control (TSMC) methods to control the output voltage of CDFIG. The SMC and TSMC methods are identified as strong controllers with large stability and robustness margins. In this paper, the SMC and TSMC methods are evaluated and compared to the conventional Voltage Oriented Control (VOC) in terms of output voltage change, prime over speed’s variation, and nonlinear load. Simulation and experimental results using a TMS320F28335 based prototype system show that the SMC and TSMC techniques are more robust against parameter variations and uncertainties, and TSMC offers improved dynamic response.
Mahdi Arabsadegh, Aref Doroudi,
Volume 21, Issue 4 (December 2025)
Abstract
This paper presents an advanced methodology for post-storm power system restoration. A real-time Condition Index (CI)-based classification scheme is introduced to categorize circuit breakers into high-reliability (Type A) and moderate-reliability (Type B) groups. Leveraging this classification, a genetic algorithm (GA) optimizes microgrid configurations to maximize power restoration probabilities by explicitly modeling the stochastic failure risks associated with circuit breakers under severe weather conditions. The approach was validated on the IEEE 118-bus system with five critical breakers deactivated due to storm conditions. The GA achieved a 92.5% load restoration after 200 iterations, surpassing a baseline Monte Carlo simulation that attained 85.2%. Computational efficiency was significantly improved, reducing execution time to approximately 15 minutes compared to 60 minutes for traditional methods, with enhanced accuracy indicated by a 1.8% error margin versus 7.5%. Key contributions include utilizing live CI data for dynamic breaker classification, which resulted in a 20% reduction in computational time, and demonstrating scalability and effectiveness on large-scale test systems such as the 118-bus network. The methodology's performance decreases to 78.3% load restoration when more than 14 breakers are compromised. Future research will focus on integrating detailed storm modeling—including wind speed profiles—and incorporating renewable energy resources to enhance grid resilience.
