البحث — المستودع الرقمي العراقي

المستخلص: اصبحت محركات التيار المستمر عديمة الفرش شائعة جدا في الكثير من المجالات مثل في الصناعة والتطبيقات المنزلية؛ وذلك يعود الى مميزاتها العديدة على محركات التيار المستمر ذوات الفرش والمحركات الحثية؛ مثل كفائتها العالية, كثافة قدرتها العالية وحجمها الصغيرنسب | Brushless DC (BLDC) motors have become very popular in various fields such as in industry or home appliances; and that is due to their many advantages over the brushed DC motors and the induction motors such as their higher efficiency, high power density and respectively low volume. The traditional and most popular way to drive BLDC motor is by using six - step or trapezoidal technique. This technique however has several problems such as high torque ripple and high distortion in the currents. This thesis presents a BLDC motor drive system where the performance of the motor is improved on various aspects. The first aspect is to improve the speed response by using particle swarm optimization (PSO) technique to find the optimal parameters of the speed controller. The second aspect is to reduce the torque ripple associated with the traditional driving technique and also improve the dynamic response of the motor by using vector or field - oriented control to drive the motor. The third aspect is improving the total harmonic distortion (THD) of the voltages and currents by using multilevel inverter. The last aspect is driving the motor in sensorless operation for reduced cost and for applications where speed and position sensors cannot be used; this operation uses a flux - linkage observer with a phase - locked loop (PLL) structure to estimate the position and speed of the rotor. The control methods are modeled using MATLAB/Simulink program and the results show that the proposed systems has significant improvement in performance as compared with the traditional technique in terms of speed response, torque ripple and THD of the voltages and currents

خوارزمية فعالة للسيطرة على التردد اثناء تغيير الحمل في منظومة القدرة == An Effective Algorithm Of Load Frequency Control In Power System

اسم المؤلف: ساره عباس حسين

اسم المشرف: قاسم عبد الرزاق الانباري | عباس حسين مري

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

السنة: 2016

الموضوع الدقيق: هندسة الكهرباء - قدرة ومكائن

الدرجة: ماجستير

الجامعة: الجامعة المستنصرية - كلية الهندسة - قسم الهندسة الكهربائية

اللغة: الانكليزية

مكان الجامعة: بغداد

الصفحات الاولى:

المستخلص: في السنوات السابقة، زادت اهمية تحسين النظام الكهربائي. وان ثبوت التردد هو واحدة من الاشياء التي اثرت في خصائص النظام الكهربائي هي ثبوتية التردد. ولهذه الغاية، وحدة التوليد ملحقة بمسيطر اوتوماتيكي على التردد اثناء تغيير الحمل (LFC) لتنظيم القدرة الفعالة | In recent years, the importance of improving electrical power has been increased. One of the things influenced the characteristic of electrical power is the constancy of frequency. To this end, the generator unit is equipped with an automatic load frequency control (LFC) to adjust the active power produced and restore the frequency and tie line power exchange to their nominal value.The total model of a hybrid power system has a high dimension. The classical design tools are inadequate to cope with all dynamic features. Artificial intelligence techniques are found to be a promising tool to optimally minimize the transient dynamics and control efforts in a load frequency control. This thesis shows the execution of various Artificial Intelligence techniques on the tuning of PID controller in a load frequency control system to compute the PID controller. The techniques of genetic algorithm technique GA, particle swarm optimization PSO and artificial bee colony ABC were applied on four areas, six tie lines power system. The dynamic model was formulated in state variables form. A comparison between these techniques with different performance indices was presented. Results of the test system 1 and 2 were computed and compared. They showed that in test system 2 the load frequency controller can chase the load fluctuation in a short time. The IAE performance index gives an optimum dynamic performance using ABC. From the outcomes, they show that the test system 2 outputs regarding settling time and maximum overshoot were the best performances.

تصميم وبناء شاحنة بطاريات ذكية لمنظومة القدرة التي تعمل بالالواح الفوتوفولطائية == Design And Implementation Of An Intelligent Battery Charger For A Photovoltaic Power System

اسم المؤلف: حسين سعود مرض

اسم المشرف: عصام محمود عبد الباقي

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

السنة: 2016

الموضوع الدقيق: هندسة الكهرباء - قدرة ومكائن

الدرجة: ماجستير

الجامعة: الجامعة المستنصرية - كلية الهندسة - قسم الهندسة الكهربائية

اللغة: الانكليزية

مكان الجامعة: بغداد

الصفحات الاولى:

المستخلص: ان الهدف الرئيسي من هذه الرسالة هو استخدام الطاقة الشمسية لشحن بطاريات الرصاص الحمضية. تعتبر الشاحنة من اهم اجزاء المنظومة الشمسية وذلك لكون بطاريات الخزن هي الجزء الوحيد المحدود العمر منها. بطاريات التخزين ضرورية في جميع المنظومات الكهربائية الشمسية المس | The main goal of this thesis is to use the photovoltaic (PV) power to charge Lead - acid batteries. The charger is the most important part of the solar system because the only limited - age part of this system is the storage batteries. Storage batteries are essential in all standalone PV power systems. Their efficiency and life time affects significantly the overall PV system performance and economics. The storage battery's effectiveness depends on the charging process. Hence, this thesis deals with the study, simulation and design of an intelligent charger fed by solar system due to the latest technologies.The developed charging method entitled "the decreased charging current based on state of charge" is adopted in this thesis to charge a lead - acid battery. The principle of decreased charging current is to make the real charging current as close as possible to the maximum acceptable current. The advantage of this technique is to mix between the rapidity of charging and prevents of the overcharging and generates gases.The maximum power point tracking (MPPT) technique is adopted to maximize the PV output power, whatever of the temperature and irradiation conditions. The design considers different operating conditions of load, battery state of charge (SOC) and ambient effect in order to achieve the best charging condition of the batteries and to be compatible with the user requirements. The flexible, simple and cheap design is the objective of this charger.This PV charging system is composed of a solar panel, lead - acid batteries, buck converter as power charging circuit and a microcontroller as a control unit.The simulation results are achieved by using Simulink Proteus Isis Professional software. These results demonstrated the validity of the proposed charging technique. The battery charger prototype was tested and the obtained results agree with those obtained from the simulation