البحث — المستودع الرقمي العراقي

المستخلص: In this thesis, a proposed control strategy is presented to improve the performance of the PWM boost type rectifier when operating under different supply voltage conditions (balanced, unbalanced, and distorted three - phase supply voltages). The proposed control strategy is classified into two parts, the first part is voltage controller and the second part is current controller. In the voltage controller, Repetitive Controller (RC) is used to reduce the even order harmonics in the regulated output dc voltage (5.62V (P.P.)) so small output capacitor (480µF) is used instead of large capacitor (920µF) that is used with the conventional controller (PI controller connected in series with a LPF). RC also reduces the even order harmonics (0.014A (P.P)) which appears in the reflected dc current (IMAX), this leads to reduce the odd order harmonics (0.01A) which appears in the input currents. While in the current controller, enhanced Phase Locked Loop (EPLL) technique is used to obtain sinusoidal and balanced three phases, to construct the reference currents, which are in phase with the fundamental supply voltages Therefore, the supply - side power factor is kept close to unity (0.9036 for extremely distorting case). As a result the calculations of the reference currents in the proposed control strategy does not require Clarke or Park transformations, the same for the calculations of the positive or negative sequence components. A proportional controller is used to give excellent tracking between the line and the reference currents. Using this approach makes the control strategy easy to understand and also it saves calculation time of the control algorithms if implements in real time. The complete system with the proposed control strategy is simulated using Matlab/Simulink (Version 2012). The obtained results for the complete system using repetitive voltage controller are compared to the results of the system with using the conventional voltage controller. The results with the repetitive controller show better responses and stable operation in the steady state under different input voltage conditions, as well as in the transient response under different disturbances.

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تحقيق دائرة المعدل الثابت للانذار الكاذب باستعمال منظومة البوابات المنطقية المبرمجة موقعيا Modified GO - CFAR Implementaion Using FPGA

اسم المؤلف: مصطفى صبحي كمال

الجامعة: الجامعة المستنصرية - كلية الهندسة - قسم الهندسة الكهربائية

اسم المشرف: رفعت طالب حسين حكمت نجم عبد الله

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

الموضوع الدقيق: هندسة الكهرباء

الدرجة: ماجستير

اللغة: الانكليزية

السنة: 2006

مكان الجامعة: بغداد

المستخلص: هذه الاطروحة تتعلق بتحليل ومعالجة تاثير الضوضاء المحيطية (Clutter) لمنظومة الرادار النبضي، يتطلب رادار الكشف الالي للهدف استعمال عتبة الية (Adaptive threshold) لتحقيق معدل ثابت للانذار الكاذب وذلك لغرض السيطرة على الانذار الكاذب الذي تسببه تغيرات في الضوض | This thesis deals with the analysis and processing of clutter for pulsed radar system. Automatic target detection radar requires adaptive thresholding achieved by Constant False Alarm Rate (CFAR) circuit in order to control the false alarm caused by variations in clutter background.This work focus on worst radar environment that happens when abrupt variation in clutter background merged with multi - interfering target, to detect target in such environments it need robust CFAR algorithm that excise the target spikes and clutter edges from CFAR window in order to give best possible estimation to the noise background. two important algorithms studied which are CA - CFAR and OS - CFAR algorithms in additional to the modified CA - CFAR algorithm. All these algorithms were simulated with mat lab v6.1 and applied them to three different clutter models that represent different environment cases the CA - CFAR family failed to handle model two and three also OS - CFAR family except OSGO - CFAR that handle all models successfully. For modified CA - CFAR family only modified GO - CFAR handle all models successfully and comparing with OSGO - CFAR the modified GO - CFAR need less hardware and processing time because it did not need sorting process that is essential for OSGO - CFAR. Therefore, the modified GO - CFAR is chosen to implement by using FPGA and another important feature in modified GO - CFAR algorithm that is parallel processing since the spike selection process is done at the same time with summing of samples process that make this algorithm much less in processing time from any other algorithm that work in the same environment. The FPGA chip that used to implement modified GO - CFAR algorithm need only three signals from the radar receiver to mach with the receiver circuit correctly which are time base clock signal period reset trigger signal and the pulse duration time. Therefore, the FPGA chip can work effectively with almost any radar receiver system

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تحليل الاشارات المشفرة ثنائيا باستخدام الترشيح الموائم وغير الموائم لتقليل الفصوص الجانبية Analysis Of Binary - Coded Signals Using Matched And Mismatched Filtering For Sidelobe Reduction

اسم المؤلف: صلاح حسن عباس

الجامعة: الجامعة المستنصرية - كلية الهندسة - قسم الهندسة الكهربائية

اسم المشرف: اسماعيل محمد جابر

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

الموضوع الدقيق: هندسة الكهرباء

الدرجة: ماجستير

اللغة: الانكليزية

السنة: 2009

مكان الجامعة: بغداد

الصفحات الاولى:

نظام الاخفاء الصوري المعتمد على تحويل المويجة والاشارات الفوضوية

اسم المؤلف: سرى فهمي يوسف

الجامعة: الجامعة المستنصرية - كلية الهندسة - قسم الهندسة الكهربائية

اسم المشرف: حكمت نجم عبد الله

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

الموضوع الدقيق: هندسة الكهرباء

الدرجة: ماجستير

اللغة: الانكليزية

السنة: 2014

مكان الجامعة: بغداد

الصفحات الاولى:

تحسين التمييز للشبكات العصبية المنعدمة الاوزان Recognition Enhancement of Weightless Neural Network

اسم المؤلف: عمار علي مصطفى

الجامعة: الجامعة التكنولوجية - قسم الهندسة الكهربائية - فرع الهندسة الكهربائية

اسم المشرف: محمود حمزة المفرجي

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

الموضوع الدقيق: هندسة الكهرباء

الدرجة: ماجستير

اللغة: الانكليزية

السنة: 2014

مكان الجامعة: بغداد

الصفحات الاولى:

تحسين الفولتية وتقليل خسائر منظومة الشبكة العراقية باستخدام افضل جهاز FACTs Improvement of Voltage Profile And Reduce Iraqi Grid System Losses By Using Optimal FACTs Device

اسم المؤلف: سيف اسعد عبد الحسين

الجامعة: الجامعة التكنولوجية - قسم الهندسة الكهربائية - فرع الهندسة الكهربائية

اسم المشرف: رشيد حميد الربيعي انعام ابراهيم علي

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

الموضوع الدقيق: هندسة الكهرباء

الدرجة: ماجستير

اللغة: الانكليزية

السنة: 2014

مكان الجامعة: بغداد

المستخلص: الغرض من هذا العمل هو تحسين الجهد والتقليل من خسائرالقدرة للشبكة العراقية ( 400kV ) عن طريق تركيب اجهزة ( FACTs ) في مواقع مختلفة تحت حالة خطا ومقارنة النتائج مع تلك دون وجود (FACTs) تحت نفس الظروف.تم تحديد الموقع الامثل للـ(FACTs) على اساس الخوارزميات | The aim of this work is to improve the voltage profile and reduces power losses of Iraqi (400kV) power grid system by installing Flexible Alternating Current Transmission System devices (FACTs).The optimal location of the FACTs device was specified based on Genetic Algorithm (GA) optimization method and power system analysis toolbox ( PSAT) package, it was utilized to search for optimum FACT parameters setting and location based objective function that depends on the power and voltage as fitness.MATLAB (R2011a) was used for running both GA program and Power System Analysis Toolbox (PSAT) version 2.1.6, Newton Raphson method also used for solving the load flow of the system and the Trapezoidal method for the non - linear differential equations.Two systems have been implemented in this work as follows; • IEEE - machine 9 - bus system.• INSGS 11 - machine 24 - bus, 39(400kV) overhead transmission line.The GA program is implemented on IEEE 9 - bus system, then after getting the appropriate results the same procedure repeated for the Iraqi grid system which is more complicated, its used to find the optimal location of Unified Power Flow Controller (UPFC). The results obtained from GA have been compared with PSAT and showed that the installation of (UPFC) devices at the optimal locations of the Iraqi grid gives an improvement in the power losses and voltage after subjected to the three phase fault to ground at different locations and different cases (temporary fault, permanent fault).

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نموذج مقترح للتعامل مع فشل العقدة في شبكة الاستشعار اللاسلكية Proposed Model To Handle Node Failure In Wireless Sensor Network

اسم المؤلف: مصطفى خالد مزعل

الجامعة: جامعة بغداد - كلية الهندسة - قسم الهندسة الكهربائية

اسم المشرف: ضياء جاسم كاظم

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

الموضوع الدقيق: هندسة الكهرباء

الدرجة: ماجستير

اللغة: الانكليزية

السنة: 2014

مكان الجامعة: بغداد

المستخلص: Wireless Sensor Network (WSN) contains many low cost and low power sensor nodes (SNs), these nodes may fail to communicate with each other according to some reasons such as battery lifetime, uncontrolled events or any surrounding environment actions which will lead to partition the network and reduce the Quality of Service (QoS) as well as the reliability and efficiency of the whole network. The motivation of this work was detecting these malfunctions using three approaches considered with two proposed network models : random distributed SNs and real model.Firstly, localization approach in WSN are discussed and verified using four classic localization methods to detect any failed SN, which are : Distance Vector (DV - Hop), Angle of Arrival (AoA), Time of Arrival (ToA) and Received Signal Strength Indicator (RSSI). These methods are analyzed and implemented for three different areas, each with three different numbers of SNs. All of them are implemented using MATLAB programming language. Secondly a known fault detection method called Distributed Fault Detection (DFD) discussed and implemented using MATLAB also, and a new method developed from this method named (MDFD) to overcome the disadvantages of DFD method. Finally the feature of the connectivity of the SNs themselves within the network is exploited by using two Medium Access Control (MAC) protocol standards : Sleep Medium Access Control (SMAC) and Tune Medium Access Control (TMAC) protocols, then proposed a modified MAC protocol (MMAC) to enhance the most affecting factors of these two MAC standards such as energy consumption and latency. The performance analysis of these three MAC protocols is verified and simulated using a real model for Iraq, Baghdad, Al - Kadhumyah City, by Castalia 3.2 simulator also designed and implemented these three protocols using an iOS application by the XCode program for general application sensors especially for explosives detection sensors, Fido® X3 sensor proposed forthis application. Simulation results showed that the localization methods proved their ability to localize the failed SNs, but with impractical errors (about 23%) in results than the other approaches, and additional load effect on the network due to execute the localization programs separately before each node failure detection. The DFD approach applied with homogeneous WSNs only that contain only one type of sensors, its errors (starting from 25% for three SNs) was due to its algorithm limitations in using only half of the neighbor SNs, reduced in MDFD method algorithm in which all neighbor SNs considered to detect the failed SN reaching full detection accuracy but with latency tradeoff. The MAC approach is better than localization approach because there is no need to additional hardware for node failure detection; it is also better than DFD approach because it was applicable with both homogeneous and nonhomogeneous WSNs. The three MAC protocols succeeded to detect the failed SNs, but SMAC and TMAC had their tradeoff in energy consumption and latency, when SMAC had less energy consumption (69.62% than TMAC), while TMAC had less latency (27.58% than SMAC). MMAC is combining the advantages of both SMAC and TMAC that had a less energy consumption than that in SMAC by 54.16% and smaller latency than that in TMAC by 76.19% within a range of division index m : between 1 to 5.

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مقترح بروتوكول توجيه الانترنيت الاشياء بالاعتماد على شبكات الاستشعار اللاسلكية Proposed Routing Protocol For Internet of Things Based On Wireless Sensor Networks

اسم المؤلف: عمر عبد الستار حماد

الجامعة: جامعة بغداد - كلية الهندسة - قسم الهندسة الكهربائية

اسم المشرف: ضياء جاسم كاظم

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

الموضوع الدقيق: هندسة الكهرباء

الدرجة: ماجستير

اللغة: الانكليزية

السنة: 2014

مكان الجامعة: بغداد

المستخلص: The routing protocol designed for Internet of Things (IoT) systems has to be adapted with different applications requirements in order to enhance the performance of IoT applications. Therefore, the main objective of this thesis is proposing a routing protocol for wireless sensor network employed to serve IoT systems. A new IoT architecture was proposed with explaining the main functions of each layer forming the proposed architecture. The proposed routing protocol acted according to the tasks specified in this architecture. In addition, an IoT application was proposed to be applicable in some utility organizations. The link quality, node depth and energy were used as metrics to make routing decisions. In this work, different cases were proposed to exhibit the usage of these metrics and show the differences of using each of them, then examine different techniques which deal with link quality and the difference between using node - to - node link quality and end - to - end link quality. Improvements were added to the proposed routing protocol to achieve the perfect integration with suitable Media Access Control (MAC) protocol with taking into consideration the behavior of IoT application. Regarding this orientation, two approaches were suggested; the first includes the proposed routing protocol, application with high data rate and MAC protocol without sleeping capabilities; while the second approach included the proposed routing protocol, application with dynamic data rate and MAC protocol with sleeping capabilities. Comparison with other protocols was essential to show the improvements achieved by this work, thus protocols designed to serve the same purpose such as AODV, REL and LABILE were chosen to compare the proposed routing protocol with. To add integrative and holistic, some of important features such as actuating and mobility were added and tested. These features were greatly required by some of IoT applications and improving the routing protocol to support them made it more suitable for IoT systems. The proposed routing protocol was simulated using Castalia - 3.2 and all proposed approaches were examined to show the enhancement achieved by each approach. The results showed better performance when using end - to - end link quality. The results also showed the effect of MAC protocol if decreasing energy consumption was required. Sleeping MAC was the best choice when used with the proposed routing protocol while reducing the data rate. The proposed routing showed better performance than other protocols did regarding Packet Delivery Ratio (PDR) and latency. It preserved network reliability since it did not generate routing or data packets needlessly. Routing protocol with added features (actuating and mobility) showed good performance. But that performance was affected by increasing the speed of mobile nodes.

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تصميم هوائي ضوئي يعمل ضمن نطاق تحت الحمراء الترددي باستخدام تقنية البلازمونك Optical Antenna Design In Ir Range Using Plasmonic Technology

اسم المؤلف: هادي كريم شمخي

الجامعة: جامعة بغداد - كلية الهندسة - قسم الهندسة الكهربائية

اسم المشرف: محمد ناظم عباس

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

الموضوع الدقيق: هندسة الكهرباء

الدرجة: ماجستير

اللغة: الانكليزية

السنة: 2014

مكان الجامعة: بغداد

المستخلص: Optical antennas, resonant structures, which efficiently collect free - space light and focus it into a nanoscale volume using plasmonic, are indispensable in the burgeoning field of nanophotonics. In this work, resonance behaviors of the fundamental resonance mode of diabolo gold metal bar optical antennas were investigated. The relationship between the near - field enhancement, absorption, and scattering spectra of localized plasmonic elements was explored. It was found that as the waist of the diabolo gold metal bar optical antenna was reduced, optical energy absorption cross section and near field enhancement at resonance increased significantly. Also reduction of the diabolo waist width caused redshift of the resonant wavelengths in the spectra of absorption cross - section, scattering cross - section, and the near electric field. Oppositely, it was found that as the length of the diabolo gold metal bar optical antenna was reduced, optical energy absorption cross section and near field enhancement at resonance decreases significantly. Also reduction of the diabolo length caused blue - shift of the resonant wavelengths in the spectra of absorption cross - section, scattering cross - section, and the near electric field.Grating surface diabolo antenna design was proposed. It was found that grating superstructure perturbed the optical properties of SPPs (Surface Plasmon polarions) and enabled the control of resonance wavelength of the antenna. The grating reduced the power that flow out from the antenna and enhanced the localized electromagnetic fields intensity. The grating also increased surface plasmon currents because of the formation of bound surface states. As a result, the absorption spectra and near field intensity were enhanced but at the same time, the scattering spectra and the far field pattern were reduced.Titanium - Gold grating surface diabolo antenna was proposed. It was found that titanium metal strengthen the grating perturbation of the optical properties of SPPs and allowed wide range of wavelength shifting (3.5 ?m). Because Gold and Titanium have difference electrical resonance characteristics, less plasmon damping occurred, resulting in lower scattering efficiency and narrower plasmon line widths.Finally, system modelling and simulations is done by using electrical department super computer (24 parallel MP and 64 GB RAM) and COMSOL multiphysics 4.4 software.

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