Publications Scientifiques
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Item Ferroresonance Avoidance by Distributed Resources Reconfigurationin Islanded Power Grid(2009) Boutora, Saliha; Bentarzi, Hamid; OUADI, AbderrahmaneIn a distributed resources power grid,a capacitor bank is used for compensation purposewhen this grid isconnected to the utility. However, when this grid is islanded, thecapacitor bankwill be needed for induction generatoroperation. Ifa great capacitanceis permanently connected, it may causea severe over-voltage due toferroresonance.Inthiswork,a simulationapproachis madeforre selecting an adequate sizeofthiscapacitor thatwill not causethisabnormal phenomenonintheislandedpowergrid. Theobtainedsimulationresultsusing Simulink/MATLABmay beuseful.Item A New Approach Applied to Adaptive Centralized Load Shedding Scheme(2009) Bentarzi, Hamid; OUADI, ABDERRAHMANE; GHOUT, NADIR; Maamri, Farid; MASTORAKIS, NIKOS E.One of major contingencies of an electric power system is due to imbalance between loads and generated power. This leads to instability in the power system and hence to a blackout. A load shedding scheme may be used to avoid such problem by reducing the total load. The aim of this work is to develop a new approach applied to an adaptive load shedding scheme using recent development technology such as wide area synchro-phasor measurement. All generator frequencies that may be measured by phasor measurement units are sent to center where a magnitude of disturbance will be calculated. These measured frequencies also will be used to determine the amount of load to be shed as well as the number of shedding stepsItem A new method of oxide charges densities determination using Charge-Pumping technique in MOS structures(World Scientific and Engineering Academy and Society, 2008) Bentarzi, Hamid; Zitouni, Abdelkader; Kribes, YoucefItem Traveling wave antennas optimization using genetic algorithms(IEEE, 2008) Recioui, Abdelmadjid; Azrar, Arab; Dehmas, Mokrane; Challal, Mouloud; Bentarzi, HamidItem On low noise amplifier design for wireless communication systems(IEEE, 2008) Challal, Mouloud; Azrar, Arab; Bentarzi, Hamid; Recioui, Abdelmadjid; Dehmas, Mokrane; Vanhoenacker-Janvier, DanielleItem Voltage unbalance effects on induction motor performance(2006) Refoufi, Larbi; Bentarzi, Hamid; Dekhandji, Fatma ZohraThe reliability of electric drives and driven motors depends on the quality of the power supply voltage especially in the critical industrial process. In this work, a theoretical study of the effects of voltage unbalances, sags and swells on induction motor (IM) is performed by using the conventional method based on the theory of symmetrical components. For this study, MATLAB software program is developed for calculating currents, torque, power losses, temperature rises and derating factor. Besides, experiments have been carried out for obtaining currents, torque and power losses. An agreement that is found between the theoretical predictions and experimental data allows us to take into consideration the predicted derating factorItem Simulation of ion density distribution in the gate oxide of MOS structures(Modelling, Measurement and Control A, 2003) Bentarzi, Hamid; Bouderbala, R.; Zerguerras, A.In this work, the simulation of ions density distribution evolution within the oxide of MOS structures is performed. This simulation is achieved by solving the partial differential equation (PDE), which governs the motion of the ions in the oxide layer, subject to boundary and initial conditions. Since no closed form analytical solution is available in the literature to solve this important problem, a numerical technique based on Crank-Nicholson method is used. The evolution of ions density distribution is simulated for different values of such parameters as applied electric field and device temperature using BTS technique. The simulation results agree well with the experimental results as well as the previous published resultsItem Microstrip design of low noise amplifier for application in narrowband and wideband(IEEE, 2008) Challal, Mouloud; Azrar, A.; Bentarzi, Hamid; Janvier, D.VA low-noise amplifier (LNA) is presented in this paper. The LNA is designed and optimized for narrowband and wideband operations along with minimum noise figure around 24 GHz (K-Band). The designed LNA employs microstrip input and output matching networks; it achieves a noise figure of 3.85 dB and 10.55 dB of gain along with 10.27 dB and 17.83 dB of input and output return losses, respectively for its narrow band. Where as for its wideband it accomplishes a gain of 6.5 dB with ±0.3 dB flatness from 24 to 25.25 GHz wideband frequency range, the noise figure obtained for the presented LNA is in close proximity to the minimum noise figure over 23 - 24.5 GHz frequency rangeItem A new computer based phasor measurement unit framework(IEEE, 2009) Ouadi, A.; Bentarzi, Hamid; Maun, J.C.A Phasor Measurement Unit (PMU) is one of the most important measuring devices that can provide synchronized phasor measurements of voltages and currents in real time from widely spread locations in an electric grid. Indeed this device is crucial to the detection of disturbances and characterization of transient swings. In this work, a new PMU has been designed and implemented including the hardware architecture and the software program using a recent developed algorithm of phasor measurement and frequency estimation. The developed PMU is based on computer associated with an acquisition card AD512 using Matlab as software tool for developing its running program as well as its graphical user interface. Finally, this PMU has been tested in laboratory using network simulator that gives good measurements with an acceptable errors even at offfrequencyItem Combating multiple access interference in wireless communication systems employing smart antennas(IEEE, 2009) Recioui, Abdelmadjid; Bentarzi, Hamid; Azrar, Arab; Dehmas, Mokrane; Challal, MouloudSmart Antennas constitute a promising technology in wireless communication systems as they mitigate multiple access interference through spatial filtering. One basic building block of smart antennas is the antenna array itself. This latter generates a wide range of aspects that can be the subject of deep investigations namely their geometry, physical parameters, feeding techniques etc... Hence, it is important to investigate whether certain array geometry will enable optimal performance. In this work, the effect of the array geometry choice on the interference rejection capability is investigated. Linear and circular array geometries are considered with mutual coupling between real antenna elements taken into account. Assessment of both geometries is done through a figure of merit that takes into account the rejection capability and radiation characteristics of the array