Renewable energy sources such as photovoltaic arrays and fuel cells play a crucial role in reducing dependence on fossil fuels and promoting environmental sustainability. Since these sources typically generate low-level DC voltage and have limited power capacity, voltage step-up is essential for their efficient integration into power grids or industrial systems. The inherently low output voltage poses significant challenges for direct load or grid connection, making high-efficiency DC-DC converters a vital component in power-conversion systems. Achieving high efficiency in DC-DC power converters has therefore become a critical criterion in practical applications.In this context, this paper introduces a dual-switch ultra-step- up converter derived from a quadratic boost structure. The proposed design integrates two cascaded boost stages, a coupled inductor, a voltage-multiplier circuit, and a switched capacitor, enabling a high voltage gain without the need for a transformer or a large turns ratio. Furthermore, the current-sharing approach through parallel diode paths significantly reduces diode losses and improves overall efficiency. Key features of the converter include reduced voltage stress on the switches, low input- current ripple, minimized diode and switch losses, simple control due to synchronous switch operation, and a common ground configuration.In addition, the proposed converter is compared with similar coupled-inductor-based converters reported in the past four years in terms of semiconductor stress, voltage gain, input-current ripple, and efficiency, demonstrating its superior performance. Finally, experimental validation on a 200-W prototype with a 24-V input and 400-V output confirms the high efficiency and outstanding performance of the proposed converter.

In this thesis, a novel artificial intelligence-based method is proposed for fast and accurate fault detection in three-phase three-level inverters. This approach analyzes current and voltage signals, extracts key features, and employs machine learning algorithms such as Random Forest and SVM to learn the system’s behavior under both normal and faulty conditions, enabling effective fault identification. To evaluate performance, simulations were carried out in the MATLAB/Simulink environment, and the resulting data were used for training and testing the model. The results indicate that the SVM model outperforms the other models used in this study in terms of speed. It is noteworthy that, in addition to achieving high accuracy, the proposed method also demonstrates good generalization capability, which enhances system reliability and reduces maintenance costs in power systems. Furthermore, the method can be further improved in the future through the integration of deep learning and reinforcement learning algorithms.   

Direct current (DC) microgrids have recently attracted more attention from researchers due to their advantages over alternating current (AC) microgrids, such as the absence of transmission losses related to reactive power flow, the absence of harmonic currents, and the simple integration of resources with DC loads. However, the constant exchange of information in the secondary control layer in the cyber environment for voltage recovery and optimal resource management has presented these microgrids with challenges such as high communication costs, the need for high communication bandwidth, and cyber threats. Denial of service (DoS) attacks and false data injection (FDI) attacks are dangerous examples of these threats that can lead the system to instability and even collapse. DoS attacks have extremely destructive effects on the system by temporarily or permanently disrupting access to critical system information. On the other hand, FDI attacks can secretly and noticeably cause harmful disturbances in the system by injecting false data into the transmitted information. In this study, an edge-based event-triggered control structure is proposed as a suitable and optimal alternative for permanent information exchange in second-layer distributed control, which is able to ignore DoS attacks. Based on this structure, information exchange between units occurs only when the sending conditions are met. Also, a decentralized approach based on a multilayer perceptron (MLP) neural network is introduced to detect FDI attacks. The advantages of this approach include high flexibility, reduced information transmission in the cyber environment, reduced complex calculations, and increased information security. Also, a threshold for an FDI attack is determined so that mitigation operations are performed only when the attack occurs. A microgrid consisting of three generating units and a DC voltage bus is simulated under different scenarios to investigate the effectiveness of this study. The results obtained show that the event-triggered (ET) structure is resistant to DoS attacks and the proposed approach is able to detect FDI attacks with high accuracy in the presence of DoS attacks and in the ET communication structure and mitigate its effects. Keywords: Direct Current Microgrids, Denial of Service Attacks, False Data Injection Attacks, Edge-based Event-triggered, Distributed Control, Multilayer Perceptron Neural network

  Modern power systems rely on advanced technologies and communication networks that enable efficient monitoring, control, and operation of physical equipment. These tools offer diverse services in terms of functionality and enhanced reliability; however, their increasing use has led to a rise in vulnerabilities and cyberattacks. Such vulnerabilities have serious consequences, including blackouts and detrimental effects on electrical infrastructure. Therefore, developing effective models for identifying and classifying adverse events in power systems for the prompt issuance of control commands is of great importance. In this context, cyberattacks on SCADA systems, which are widely used for monitoring large production systems and modern power networks, have become a significant challenge. These systems are particularly vulnerable to various cyberattacks due to their unique features, including remote communications and management of critical infrastructure. Detecting these attacks using traditional Intrusion Detection Systems (IDS) is challenging due to the complexity and diversity of threats, highlighting the need for innovative and effective methods for accurate identification of these attacks. In this regard, a two-stage feature selection method utilizing Principal Component Analysis (PCA) and the War Strategy Optimization (WSO) algorithm, along with a Feedforward Neural Network (FFNN), has been proposed. In this method, the number of layers and the number of neurons in each layer of the FFNN are optimally determined by the WSO algorithm. This approach is designed for the precise identification of malicious attacks. The performance of the proposed method has been evaluated using laboratory SCADA system data, and the results demonstrate satisfactory effectiveness in detecting cyberattacks. This research can significantly enhance the resilience and safety of SCADA systems against cyber threats and serve as an effective solution for managing and mitigating risks arising from cyberattacks on critical infrastructure.

Abstract The islanding of interconnected power systems, which is also known as the isolation and breaking of power systems, is the last defense method to deal with the collapse of the system and prevent the occurrence of catastrophic events in the power network, which as a widespread control method is a comprehensive decision problem with There are many details and it is presented as an important part of corrective control strategies. After the occurrence of a major disturbance in a power system, if there is no suitable solution plan and model in time, this disturbance may lead to the total collapse of the system. Islandization of power systems means determining the correct points of isolation of the integrated system into a number of smaller islands if maintaining the integrity of the system is not possible. The aim of this thesis is to provide a method to predict the appropriate time for applying controlled islanding in the network by means of indicators based on the relationships between the generator harmonic groups. The defined indicators can predict the weakening of security and fragility of the network in the context of the dynamic behavior of the system and as a result the islanding of the network with high speed and accuracy and in a timely manner. The IEEE 39 bus network has been used to obtain the critical limit of the introduced indicators in a timely manner and to predict the appropriate time for islanding in a timely manner. The results obtained from the dynamic simulation indicate that the controlled islanding at the right time can prevent the occurrence of consecutive incidents, global blackouts and crises in the network.   

Nowadays, in order to improve the features and flexibility of DC microgrids, energy storage systems, generation sources, and various loads are connected to each other through bidirectional isolated DC-DC converters for better integration and power exchange between the buses. The Dual Active Bridge (DAB) converter, which is considered an engineering masterpiece among isolated converters, has attracted significant attention due to its numerous advantages such as bidirectional operation, high voltage capability, galvanic isolation, buck-boost functionality, and high efficiency resulting from soft switching. In recent years, the performance of this converter has improved based on different control modulations, including traditional methods such as Single-Phase Shift (  ) and Extended Phase Shift (EPS), which researchers have studied Conventional approaches for modeling these types of converters pose significant challenges and difficulties. DAB converter modulation is an interesting part of ??research, as traditional modulations have significant limitations such as restricted switching regions. Therefore, to overcome these limitations, dual phase shift (DPS) and hybrid phase shift (HPS) modulations have been introduced. Furthermore, another aspect of the efficiency of the DAB converter lies in its ability to connect to various systems, including energy storage devices In explaining the mentioned modulations, operational waveforms are first analyzed for different switching conditions, followed by a control strategy for achieving the desired power transfer. In this thesis, after studying the details of the previous phase shift modulations and presenting new modeling techniques and closed-loop control for the converter, the design process has been thoroughly analyzed in the software environment (Matlab/Simulink). Also, the specifications, design of parameters and the equivalent circuit of the DAB converter have been completely described and different scenarios have been performed in the simulation and obtaining its results. The comparison of the modulations in terms of efficiency, common mode voltages, and zero voltage switching area confirms the accuracy and correctness of the theoretical contents. The simulation results show the success of the control modulations in power transmission operations by the DAB converter. As a result, the DAB converter has a suitable performance for placement in the DC microgrid simulator system. Keywords: Dual Active Bridge (DAB), Phase Shift Modulation, DC Microgrid, Energy Storage Systems, Closed Loop Control,   , EPS, DPS, HPS.   

In independent microgrids located in remote areas, the development of reliable and self-sufficient renewable energy systems is one of the major challenges of operating power systems due to the lack of connection with the national power grid. One of the best future options for increasing the use of renewable energies in grid-independent systems is the use of energy storage systems. In this thesis, an optimization model is proposed to determine the most cost-effective combination of renewable energy capacity using the war strategy optimization algorithm in a grid-independent microgrid supported by battery energy storage technology. The problem of energy management has been formulated using linear programming and the proposed algorithm has taken into account the limitations of exploitation, technical and land use. Also, the hourly effects of the region's weather and load demand, along with the installation price, have been evaluated. The simulation results for the diesel-based microgrid, which is a benchmark, and the renewable microgrid based on LCOE (levelized cost of electricity), have been compared and analyzed. In addition, sensitivity analysis is also presented to investigate the effect of variables on LCOE and PC (present cost) of the system. According to the tests and the obtained results, the lowest amount of PC is related to the scenario that has both a reduction in storage costs and a reduction in demand for consumption, which is 2113200 (€). Also, the results in this section show that the renewable microgrid has a higher LCOE (from 0.39 to 0.48 (€/kWh)) than the diesel-based approach (from 0.21 to 0.48 (€/kWh) is watt hours.   

   As we know, the structure of electricity networks around the world is changing and evolving. So that distributed production in the form of micro-grid (MG) is expanding. Normally, an MG consists of several scattered production sources, and energy storage systems (batteries) are used for continuity of energy production in new MGs. In such networks, determining the charging and discharging time of the batteries requires having sufficient information about the state of energy production and consumption or the size of the MG bus voltage. Normally, sensors are used in MGs to get information about the above-mentioned things. Using a sensor in any system reduces its reliability. Because there is a possibility of failure in the sensors. For this purpose, the use of sensorless methods to estimate the MG bus voltage creates better conditions in creating more confidence in the MG's reliable performance. Therefore, in this research, an artificial neural network (ANN) model is proposed for MG modeling. Because A   have shown to be capable of modeling non-linear systems. It should be noted that the MG under study in this work consists of a distributed production unit (solar energy) and an energy storage system unit (batteries). In this way, three ANN models have been created to estimate MG bus voltage. So that the first model estimates the output voltage of the photovoltaic array, the second model estimates the current of the storage system, and the third model estimates the MG bus voltage. To evaluate the performance of the created models, the mean square error (MSE) of each model has been calculated. The test results show that the error of the proposed models is very low and close to zero, which means that the models can predict the output with high accuracy. Finally, it should be said that the accuracy of the first model that estimates the voltage of the photovoltaic array is higher than the other two models.

   ريز شبكه يك شبكه محلي كوچك است كه   از چندين منابع توليد پراكنده و بار تشكيل شده است . از قابليت هاي ريز شبكه قابل كنترل بودن و تامين كننده توان الكتريكي مي باشد و به صورت اتصال به شبكه يا جدا از شبكه مورد استفاده قرار مي گيرد كه از مزايا ي اصلي آن افزايش كيفيت برق و قابليت اطمينان براي مصرف كنندگان مي باشد.يكي از مسائل مهمي كه در ريز شبكه ها از اهميت بالايي برخوردار است كيفيت ولتاژ به دليل افزايش بارهاي تكفاز كه از بارهاي نامتعادل هستند ميباشد.از عواملي كه در كيفيت ولتاژ متاثر است نامتعادلي ولتاژ مي باشد كه عوامل مختلف و متعددي دارد. دربخش اول اين پايان نامه عوامل ايجاد نامتعادلي ولتاژ و اثرات آن بر تجهيزات ريزشبكه شناسايي شده سپس به منظور بررسي ميزان نامتعادلي ولتاژ،استاندارد هاي پركاربرد وتعاريف متعددي از شاخص هاي نامتعادلي ولتاژ مورد توجه قرار مي گيرد.طرح پيشنهادي دراين پايان نامه به متعادل سازي ولتاژ وتحليل ريزشبكه هاي مبتني بر اينورتر مي پردازد.طرح كنترلي استفاده شده به منظور جبران سازي نامتعادلي ولتاژ ناشي از بارنامتعادل ،كنترل افتي مبتني بر فيلتر چند متغيره بهينه شده بوده كه مولفه ي مثبت ومنفي جريان را براي منابع ولتاژ مبتني بر اينورتر به هنگام بروز نامتعادلي در ريزشبكه استخراج مي كند. هدف اين طرح در واقع بهبود عملكرد سيستم كنترل افتي به عنوان قلب سيستم كنترل ريزشبكه جزيره اي تحت شرايط نامتعادلي ولتاژ مي باشد. بدين منظور فيلتر چند متغيره بهينه شده توسط الگوريتم هاي فراابتكاري بر روي سيستم كنترل افتي پياده سازي مي شود تا بتواند مولفه هاي مثبت و منفي حاصل از وجود نامتعادلي را به خوبي شناسايي و جدا سازي كند . با پياده سازي اين سيستم مي توان نوسانات ناشي از نامتعادلي ولتاژ را تا حد زيادي كاهش داد و پايداري سيستم را بهبود بخشيد. اين شبكه به منظور بررسي عملكرد سيستم كنترلي ارائه شده آن با وجود بار نامتعادل در فضاي سيمولينك نرم افزار متلب شبيه سازي شده است. در بخش دوم اين پايان نامه هارمونيك به عنوان مسئله اصلي كه بر كيفيت توان تأثير مي گذارد،مورد توجه قرار مي گيرد و طرح پيشنهادي به آشكارسازي هارمونيك مي پردازد.اين طرح كنترلي كوپل هاي نوساني ايجاد شده بين اجزاي هارمونيك را حذف ميكند.هدف اين طرح بهبودعملكرد كنترل كننده جريان و در نهايت بهبود عملكرد سيستم مي باشد.براي نشان دادن عملكرد موثر طرح پيشنهادي، در فضاي سيمولينك نرم افزار متلب شبيه سازي شده است. وازه هاي كليدي:ريزشبكه جزيره اي ، واحد هاي توليد پراكنده ، نامتعادلي ولتاژ، كنترل افتي ( دروپ) ، فيلتر چند متغيره ، آشكارسازي هارمونيك

In order to increase the reliability in supplying the energy needed by consumers, plans have been proposed regarding the behavior of resources connected to the power grid in recent years, which are called microgrids. Microgrid systems are formed by the combination of several energy production and storage systems and local consumers. These structures have recently attracted attention all over the world, because these networks can work both connected to the national network and independently or in islands, and they can also cover rural consumers or consumers far from the main network. put A large part of the production of these networks is made up of renewable energy sources such as wind turbines and solar panels. Due to the environmental problems and global warming as well as the energy crisis of the last few decades and the movement of governments towards not depending on fossil fuels, the distribution systems have faced an increase in the penetration of scattered productions based on renewable sources such as wind and solar sources. One of the important factors that affects the performance of the microgrid is the uncertainties in its various parts and components. Various uncertainties such as load uncertainty, DG availability, etc., make the management of this network a serious challenge. With the high penetration of DGs based on renewable energies in the microgrid and the dependence of the production power of these sources on weather conditions, the operation of the microgrid has faced serious uncertainty. The presence of these uncertainties has jeopardized the security of system operation. Providing an effective and efficient solution for the safe operation of future distribution systems in conditions of uncertainty is a necessary and necessary thing. One of the main solutions for this purpose is to use an energy storage system, especially batteries, as a supplement for distributed production, especially production based on renewable energy. In addition to maintaining stability, batteries can make the microgrid a more economical option with ESS when the price of electricity is cheap or there is excess production of local resources. In addition to all these advantages, the investment cost of batteries is high and its technologies are improving and introducing new types every year. Due to the relatively low life span of these equipments, along with the cost factor, the life span is also considered as one of the most important factors for choosing batteries. Therefore, choosing the optimal number and place to install batteries, along with the type of technology chosen, is one of the most important challenges for power grid planners. In the proposed plan, a comprehensive and uncertainty-based model is presented to determine the capacity and optimal location of ESS installation in the microgrid with the penetration of renewable energy-based productions. The proposed model also evaluates the type of battery storage source technology. In other words, the proposed structure is proposed based on conventional and widely used battery models, and the effect of these technologies on the location and total cost of the microgrid is evaluated.  

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  Harmonic sources such as non-linear loads and low-frequency oscillations due to the synchronous generator rotor in microgrids connected to the high-impedance distribution grid lead to grid voltage and current distortion. On the other hand, single-phase and two-phase unbalanced loads including household loads, cause the injection of negative sequence components, therefore, unbalancing in the PCC voltage. The simultaneous presence of harmonic and negative sequence components significantly reduces the power quality of the grid. In this thesis, in order to simultaneously compensate harmonics and unbalanced voltage in microgrid terminals with interfaced inverter based on virtual synchronous generator (VSG), a combined compensation method is proposed. In this scheme, an impedance-based magnitude-reshaping method is used to remove different types of integer and non-integer order harmonics. To compensate the unbalanced voltage of the grid, the method of extracting the negative sequence components will be used by the decoupled dual synchronous reference frame (DDSRF). Two conventional PI controllers are used to compensate the unbalanced voltage. The outer loop is related to negative sequence voltage control and the inner loop is related to negative sequence current control. The compensating signals obtained from the two mentioned methods are added together and finally, enter the two-level sinusoidal pulse width modulation (SPWM) block. The simulation results obtained from the proposed method under three scenarios with harmonic and unbalanced sources are compared with conventional control methods to confirm its capability and effectiveness compared to uncompensated conditions and conventional compensators.

   به دليل توسعه ذخيره­سازهاي انرژي الكتريكي و منابع توليد پراكنده با خروجي DC و همچنين وجود طيف وسيعي از بارهاي DC ، استفاده از ريزشبكه­هاي DC در حال افزايش است.   تلفات كمتر، عدم نياز به سنكرون­سازي و كنترل فركانس و كنترل اوليه ساده­تر ولتاژ از جمله مزاياي ريزشبكه­هاي DC نسبت به ريزشبكه­هاي AC است. با اين وجود، يك ريزشبكه DC نيز داراي برخي معايب و همچنين پيچيدگي­هاي فني مربوط به بهره­برداري، كنترل و حفاظت مي­باشد. ريزشبكه‌هاي DC   نسبت به ريزشبكه­هاي AC عموماً منطقه جغرافيايي كوچك‌تري را تغذيه مي­كنند و طول خط توزيع كوتاه‌تري دارند و به عنوان شبكه‌هاي مقاومتي در نظر گرفته مي‌شوند؛ همچنين ريزشبكه‌هاي   DC اينرسي كمتري دارند و در نتيجه مستعد ناپايداري در هنگام بروز خطا يا اغتشاش مي­باشند. يكي از مهمترين چالش­ها در ريزشبكه­هاي DC، طراحي يك سيستم حفاظتي مؤثر براي آنهاست. در ريزشبكه­هاي DC، وجود خازن در فيلتر خروجي مبدل­هاي الكترونيك قدرت و خازن نصب شده در مدار ورودي بارها باعث افزايش سريع جريان خطا مي­شوند و در نتيجه، هماهنگي رله­هاي حفاظتي به طور جدي تحت تأثير قرار مي­گيرد. در اين پايان­نامه، يك رله حفاظتي تطبيقي براي تشخيص سريع بروز اتصال كوتاه در ريزشبكه­هاي DC پيشنهاد شده است. طرح حفاظتي پيشنهادي از دو قسمت حفاظت اوليه و حفاظت ثانويه تشكيل شده است. در حفاظت اوليه پيشنهادي، اتصال كوتاه­هاي با مقاومت اتصالي كم (تا حدود يك اهم) را بر اساس نرخ افزايش جريان، شناسايي مي­كند. حفاظت ثانويه پيشنهادي نيز با توجه به جهت جريان در دو سر كابل اتصال كوتاه شده، وظيفه شناسايي اتصالي­هاي با مقاومت اتصالي زياد را به عهده دارد. نتايج شبيه­سازي يك ريزشبكه DC شامل منبع توان فتوولتائيك، كه به شبكه AC متصل است؛ نشان مي­دهد؛ طرح حفاظتي پيشنهادي در كمتر از يك ميلي­ثانيه قادر به شناسايي انواع اتصال كوتاه مي­باشد. همچنين طرح حفاظتي پيشنهادي در برابر تغيير شرايط بهره­برداري از جمله تغيير بار و توان توليدي منبع توليد پراكنده، مقاوم بوده و سيگنال تريپ كاذب صادر نمي­كند.   

   Today, with increasing in the demand for electric energy consumption in the world and the limitation of the use of fossil fuels, the increasing attention of energy producers to the use of clean and renewable sources such as solar energy and wind energy has been attracted, and producers have introduced these resources as alternatives with higher reliability and quality, and better environmental and economic considerations. The use of renewable energy sources to generate electricity requires distributed generation systems in the form of microgrids. Microgrids are composed of distributed generation sources, local loads and energy storage system, and they are able to supply the required load of the system in the mode of direct connection to the national grid or island connection. AC microgrids, DC microgrids and AC/DC hybrid microgrids, are three main structures of microgrids. DC microgrids have received special attention due to their simpler control compared to AC microgrids and AC/DC hybrid microgrids. However, the lack of inertia in the microgrids, especially the DC microgrid in island mode, has caused them to have less resistance and stability margin against disturbances and fluctuations. One of the main issues in DC microgrids is voltage swing control of these microgrids. In this thesis, the design and simulation of an island mode DC microgrid which includes solar energy source, energy storage system and constant power loads is discussed. In this system, a virtual DC machine is used to improve damping and generate inertia. In order to have a stable and optimal performance of DC microgrid against oscillations and also to improve and increase the inertia and damping of the microgrid, a control method based on robust control H?   has been presented, which is able to withstand disturbances and oscillations and finally maintain the stable performance of the system. In order to investigate and analyze the proposed control method, the system studied in this research is simulated with different scenarios such as disturbances and oscillations in Simulink environment of MATLAB software. Evaluation of the simulation results proves the accuracy of the performance and the efficiency of the proposed controller. The proposed strategy by applying inertia and virtual damping, acceptably reduces the voltage oscillations of the DC microgrid and finally improves the stability of DC microgrid.

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Abstract:One of the most important types of renewable energyfor sustainable supply is solar energy, which is currently developing and expandingsignificantly.   Inappropriate voltageregulation of the distribution network, on which these microgrids are located,can lead to issues such as power quality, equipment safety, system reliabilityand stability. Therefore, the need for a suitable method to adjust the voltageof the distribution system is felt.   Manyexisting methods do not consider the delay of the communication links thatexist in the power system and ignore this important issue to design thecontroller. Communication delay, to a small or large extent, is inevitable inthe voltage regulation loops of solar cells. Meanwhile, delays with large anduncompensated time constants can lead to power system instability and voltagecollapse. Therefore, a robust method based on static output feedbackconsidering the delay of communication links has been introduced in thisthesis. The proposed method is designed by linear matrix inequality (LMI),which is used as a conventional method in power systems despite thecommunication delay, and has a simple structure and implementation and goodperformance. The proposed controller is implemented in the MATLAB softwareenvironment and the results of it comparing with the dynamic output feedbackcontroller method indicate its good performance in transient and steady stateconditions.  

AbstractWith the increase in the number ofdistributed generation (DG) and renewable energy resource units (DG/RES) andtheir penetration in distribution networks, microgrids (MG) have become veryimportant. Future of the network stabilityis endangered by increasing the number of Distributed Generation (DG) andRenewable Energy Source (RES) units. The idea of the Virtual SynchronousMachine (VSM) has been raised to control the power electronic-based DG/RESconverters in order to have better integration with the grid. This thesisintroduces a new stabilizer design for VSM-based converters to guarantee thestability of the micro-grid (MG). In this regard, the Sliding Mode Control(SMC) theory, which is robust against the disturbances and uncertainties, isemployed to cope with the intermittent and nonlinear nature of DGs. The mutualoperation of the proposed inverter and MG stabilizer has the followingadvantages: (1) It provides a seamless and robust transition from thegrid-connected to the islanded mode. (2) It is universal, sharing the real andreactive power during islanded mode and acting as a grid-supporting inverter inthe grid-connected mode. (3) It mimics the behavior of the conventionalsynchronous generator resulting in better integration of DGs into the grid. (4)It can be used both in the voltage-controlled and the current-controlledVoltage Source Converters (VSC). (5) It obviates the need for the communicationlinks, Phase Locked Loop (PLL) and islanding detection process. Themathematical model of the whole system has been investigated. The simulationresults, conducted in the SIMULINK/MATLAB environment, confirm theeffectiveness of the proposed controller.Keywords: Microgrid; Sliding modecontrol; Virtual synchronous machine  

   The quality of power and lack of use of the network are considered as two important factors in power networks, and one of the factors of ferroresonance is known as these network disturbances, which with the occurrence of this phenomenon, power quality and network security are endangered. Ferroresonance is one of the rare phenomena in power networks. In this project, first by introducing the phenomenon of ferroresonance, its different random states in the power system are explained, and also the effects in different fields are presented to start sales. Investigating and simulating the ferroresonance phenomenon is dependent on the ferroresonance circuit model and finding its state equations. In this project, by solving these equations, we investigate and simulate the random ferroresonance in the power transformer. Finally, we examine the effect of the initial conditions on this phenomenon in the power transformer. Usually, in the ferroresonance equivalent circuit, the self-impedance of the network and its resistance value are ignored, and in this project, we study the effect of ignoring these parameters.

در اين تحقيق، پديده خوردگي سايشي در تجهيزات فرآيندي حامل جريان سيال همراه با ذرات جامد مورد مطالعه قرار گرفت و با استفاده از تكنيك شبيه سازي ديناميك سيالات محاسباتي با بكارگيري نرم افزار كامسول پارامترهاي مؤثر بر خوردگي سايشي بررسي شده‌اند. در اين راستا درون مجراهاي حامل جريان هوا و ماسه با انحناهاي 45،60،90،120،135 و 180 درجه پديده خوردگي سايشي ضمن برخورد ذرات جامد جريان با ديواره لوله وخم شبيه سازي شد نوع ذرات، ماسه و اندازه ذرات موجود در سيال m150? در نظر گرفته شد و مدل‌هاي اصلي خوردگي سايشي شامل مدل Finnie،E/CRC،OKA و DNV در اين شبيه سازي لحاظ شد. براي شبيه سازي جريان سيال با توجه به آشفته بودن جريان از مدل k-? استفاده شد. دماي عملياتي 20?C، سرعت جريان هوا 11M/S و فشار خروجي مجرا 1atm درنظر گرفته شد. نتايج بدست آمده از اين شبيه سازي شامل بررسي پارامترهاي ديناميكي جريان و اثر پارامترهاي مختلف مانند سرعت، اندازه ذرات، دانسيته ذرات، قطر مجرا و...، بررسي مسير حركت ذرات و تشخيص نقاط مهم خوردگي است. بررسي اثر پارامترهاي مختلف بر روي خوردگي سايشي به صورت كمي در قالب نمودار و جدول ارائه شد اما تشخيص نقاط مهم سايش و بررسي پارامترهاي ديناميكي و نحوه حركت ذرات به صورت كيفي گزارش شد. اين نتايج نشان داد كه با افزايش سرعت سيال، دبي ذرات و افزايش انحناي مجرا خوردگي افزايش يافت و با افزايش قطر ذرات، دانسيته ذرات، قطر لوله خوردگي سايشي كاهش يافت. محل بيشتر سايش براي زانويي 45 و 60 درجه در انتهاي انحنا بود. براي زانويي 120 و 135 درجه حداكثر نرخ سايش در وسط خم رخ داد. ضمناً براي خم 180 درجه دو ناحيه با نرخ سايش بالا در زانويي وجود دارد. با تغيير سيال درون لوله از هوا به آب نرخ سايش حدود 90% كاهش پيدا كرد و براي سيال آب با افزايش قطر ذرات نرخ سايش افزايش پيدا كرد.   اهميت مطالعه تجزيه و تحليل ديناميك سيالات محاسباتي براي مطالعه نرخ سايش با استفاده از كامسول پيش‌بيني بهتري از نقاط مهم خوردگي، برنامه‌ريزي اقدامات پيشگيرانه براي كاهش وقوع سايش، برنامه تعمير و نگهداري و صرفه‌جويي در هزينه با كاهش زمان خرابي ارائه مي‌كند.   

  Objective: Improving output waveforms and overcoming theinstability effect caused by CPLs in DC microgrid is the main objective of thisresearch.

Abstract  The increasing influence of renewable energy sources, including solar energy, in the production of electrical energy, has increased uncertainties in solving various problems,control and operation of the power system.The increasing influence of renewable energy sources, including solar energy, in the production of electrical energy, has increased uncertainties in solving various problems, control and operation of the power system.The increasing influence of renewable energy sources,including solar energy, in the production of electrical energy, has caused an increase in uncertainties in solving various problems, control and exploitation of the power system.this reason, probabilistic load distribution has become an important tool for investigating the random characteristics of the power system.In this thesis, in order to investigate the amount of losses, considering the unstable behavior of loads in the form of a normal distribution, one of the Monte Carlo probabilistic load distribution methods is used.Two-point, three-point and five-point estimation are used with the help of Matlab software. In the following, the MCS&3PEM algorithm is proposed and the results obtained from it are compared with the Monte Carlo method.Also, in order to check the amount of fuel cost, the PSO algorithm has been used; PSO The obtained results will be evaluated to find the best location of photovoltaic systems, in order to reduce the cost of fuel. Two standard test systems are used to check the said methods. Also, to estimate the amount of solar radiation received in Kermanshah province using daily data obtained from meteorological station, in a period of 6 years, GMDH optimized neural network is proposed. Also, to estimate the amount of solar radiation received in Kermanshah province using daily data obtained from meteorological station, in a period of 6 years, GMDH optimized neural network is proposed.Also, to estimate the amount of solar radiation received in Kermanshah province using the daily data obtained from the weather station, in a period of 6 years, an optimized GMDH neural network is proposed.The results of the research showed that there is a small difference between the radiation values measured at the meteorological station and the radiation obtained by the model, which shows the ability of the model to estimate the radiation. The results of the research showed that there is a small difference between the radiation values measured at the meteorological station and the radiation obtained by the model, which shows the ability of the model to estimate the radiation.The results of the research showed that there is a small difference between the radiation values measured at the meteorological station and the radiation obtained by the model, which indicates the ability of the model to estimate radiation.In order to evaluate different modes of system operation, two scenarios areconsidered. First, all the loads are fed only by the main grid, and losses and production costs are expected to be high. And second, the photovoltaic system is connected to the system. Based on the results,In order to evaluate different modes of system operation, two scenarios are considered. First, all the loads are fed only by the main grid, and losses and production costs are expected to be high. And second, the photovoltaic system is connected to the system. Based on the result،In order to evaluate different modes of systemoperation, two scenarios are considered. First, all the loads are fed only by the main grid and the losses and production costs are expected to be high. And second, the photovoltaic system is connected to the system. Based on the It was found that when the photovoltaic system is connected to the system, the amount of power loss and production cost   is reducedKeywords:

  در سال­هاي اخير با ظهور ادوات الكترونيك قدرت، منابع مبتني

Due to the production of electrical energy in thermal power plants, a lot of heat enters the atmosphere through cooling towers. Therefore, the energy efficiency of these types of power plants decreases (the efficiency of these power plants is between 50 and 60 percent). Therefore, a problem named Combined Heat and Power Economic Dispatch (CHPED) plays an important role in the field of power system research because it helps to reduce production costs and also reduce pollutants emitted into the atmosphere by using waste heat through steam. In order to effectively and optimally use cogeneration units, the economic dispatch of heat and power load is considered, the purpose of this problem is to find the optimal point of power and heat production with minimum fuel cost in such a way that both heat demand and power demand can be provided  

امروزه با ورود منابع تجديدپذير به شبكه توزيع موضوعي به نام ريز شبكه شكلگرفته كه اين موضوع بخشي ازتحقيقات را به خود تخصيص داده است. ريزشبكه داراي مزيتهاي بسيار زيادي ازجمله طبيعي و اقتصادي و غيره است. اگرچه ريزشبكه داراي مزاياي بسيار زيادي است، اما ريز شبكه چالشهاي متفاوتي را نيز ايجاد كرده است. يكي از چالشهاي مهم ريزشبكه موضوع حفاظت از ريزشبكه است، كه موضوع موردبحث اين پاياننامه نيز هست. چون ريزشبكه در دو مد كاري ايزوله و متصل به شبكه كار ميكند، به همين علت بر اندازه جريان اتصال كوتاه به شدت تأثير ميگذارد. در مد كاري متصل به شبكه اندازه جريان اتصال كوتاه متشكل از جمع جريانهاي اتصال كوتاه توسط شبكه اصلي و DG هاي موجود در ريزشبكه ميباشد، اين در حالي است كه در حالت ايزوله مقدار جريان اتصال كوتاه فقط توسط DG هاي موجود در ريزشبكه تغذيه ميشود. در نتيجه به علت تغييرات سطح جريان اتصال كوتاه و وابستگي اندازه اين جريان به توپولوژي شبكه، سيستم حفاظتي اضافه جريان، توانايي حفاظت از ريزشبكه را ندارد. به همين سبب در اين پاياننامه راهكاري براي حفاظت از ريزشبكه ارائه ميشود . الگوريتم بررسيشده در اين پاياننامه از طريق محاسبات حساسيت و تغييرات توان اكتيو بر پايه اندازهگيري فازور ولتاژ به صورت همزمان در يك زون حفاظتي، خطا را شناسايي كرده و فرمان تريپ را صادر ميكند. براي بررسي بيشتر اين الگوريتم از شبكه استاندارد CIGRE در برنامه ديگسايلنت استفاده شده و الگوريتم پيشنهادي با زبان برنامه نويسي پايتون در برنامه ديگسايلنت در قسمت DSL شبيهسازيشده است. مزيت اين الگوريتم براي حفاظت از ريزشبكه اين است كه، اولا توپولوژي شبكه بر كاركرد اين الگوريتم تاثير ندارد و ثانين توانايي تشخيص انواع خطا در دو مد كاري ريزشبكه را نيز داد. در پايان براي كاركرد بهتر اين الگوريتم به قسمت تصميمگيري آن يك شرط براي ولتاژ اضافه شده، كه باعث برطرف شدن تصميمگيري اشتباه توسط اين الگوريتم در زمان خطاهاي طولاني مدت ميشود

   Nowadays power quality is one of the most important index in power systems along with other indices such as reliability, stability and security and can be affected by steady state current or transient current including short-circuits. Directional over current relays are used as the primary protection of meshed distribution and multi-sourced sub transmission systems. By using a good protection scheme, in case of fault current occurance, only the least possible portion is removed. DOCRs have mainly two settings i.e Time multiplier setting (TMS) and plug setting (PS). Proper coordinated relayes are required to clear the fault as soon aspossible to avoid further damages to the transmission system. This problem of setting proper TMS and PS of DOCRs in multi-sourced meshed systems has become very complex. CTs provide DOCR   the required current to trigger. Numerous researches and studies have been done over solving and optimizing the problem of setting proper settings among primary and back up relays but none considered CT composite error. Therfore we are about to solve the complicated phenomena of setting and optimizing TMS and PS considering the composite error of CTs. To achieve this goal we have used metaheuristic optimizing algorithms such as PSO,DE and GA combined with DE.

Displacement of vents for the internal comfort of the building  

  Abstract

   In recent years, thanks to developments in electrification, many modern applicatio   such as more electric aircrafts, electric ships, hybrid electric vehicles, smart household applications, etc,   have been emerged.   Due to this increasing demand for the electrical energy, microgrid systems have gained higher penetration in the electrical grid to effectively apply   the renewable energy sources (RESs).   DC microgrids (DCmGs)   have received more attention compared to AC ones to supply these emerging power electronic loads and due to their enefits from the viewpoints of   high efficiency, flexibility, simpler control structure, compatibility,   robustness, etc. A   islanded   DCmG   generally   consist   of   multiple   dis-tributed generation units (DGUs) interconnected by power dis-tribution lines. Each DGU flexibly integrates electrical sourcessuch as RESs and energy storage systems (E  ) to feed someof   power   electronic   load   at   it   point   of   commo   coupling(PCC). One of the main control objectives in islanded DCmGsi   to   regulate   output   voltage   of   each   DGU   at   it   reference value   by   a   control   strategy   using   a   few   communication link   a   possible. Decentralized control strategy is a most appropriate method for this aim. However, this method lacks its desired performance with increasing microgrid size and the existence of heavy interconnections between different DGUs. Therefore, the Distributed control strategy is the preferred method for controlling large-scale DC microgrids. In this control method, a local controller is designed for each DGU, which uses the measured outputs for that DGU as well as the DGUs coupled with it. The problem which we encounter in this method is the existence of a communication time delay in the measurements received from neighboring DGUs. Delays usually cause poor performance and even instability of the system. Therefore, the controller must be designed to compensate for the adverse effects of time delay. However, the design of the controller in the presence of time delay as well as uncertainty in the loads is very complex. In this thesis, using the distributed control strategy, we design an H?

  According toforecasts, the world will face an energy crisis and issues related togreenhouse effects and environmental pollution in the near future. Therefore,the use of environmentally friendly vehicles, such as electric vehicles, aswell as the trend towards renewable energy in the future, will be inevitable.According to statistics, 83% of electric vehicles use permanent magnetsynchronous motors. Also in wind turbine applications, the approach of largecompanies in the world such as Siemens and General Electric, is to use largegenerators with high power density and reliability. The share of permanentmagnet synchronous machines (PMSM) is higher than other electric machines. Thereason is the significant improvement in the properties of permanent magnetsand significant reduction in their price in recent years. Due to the popularityof PMSM in the new energy industry, research has started on the design andconstruction of well-functioning drives for these machines. In thisdissertation, the torque control of this machine has been done using the modelpredictive control (MPC) method. The aim of this dissertation is to provide amethod for simultaneously reducing torque ripple and switching frequency with asmaller computational burden than the previous methods. By reducing the torqueripple, the performance of the drive and motor is improved and by reducing thecomputational burden, it is possible to implement this method on a variety ofmicrocontrollers.Keywords: Model PredictionTorque Control, Discrete Space Vector Modulation, Switching Frequency,Permanent Magnet Synchronous Motor

  One of the major challenges for microgrids that use renewableenergy, such as photovoltaic systems, is the lack of inertia, which endangersthe microgrid stability. In recent years, the virtual synchronous generatormethod has attracted a lot of attention to meet this challenge. In fact, thismethod mimics the transient properties of a synchronous generator using therotational equation of a synchronous generator and helps to improve gridstability by creating virtual inertia. On the other hand, most photovoltaic-virtualsynchronous generator systems have energy storage systems that have issues suchas increased system costs, maintenance costs, and space occupation. Therefore,in this research, a photovoltaic-improved virtual synchronous generator systemis used, which does not require energy storage. Another challenge of microgridsis the voltage imbalance and the proper operation of the control system underunbalanced conditions. So far, various methods have been proposed to compensatethe unbalanced voltage, many of which impose additional costs on the system. Inthis research, using the double decoupled reference frame method, the positiveand negative components of voltage and current are seperated and the PCCvoltage is balanced. In summary, this research presents an island PV-improved VSGsystem that is able to compensate voltage imbalance at the PCC. This system issimulated in the MATLAB / Simulink, and the simulation results show thatsimultaneously the dynamic stability in the transient state is improved usingvirtual inertia, and it is also possible to compensate the unbalanced voltageat the PCC.

nowadayswe have entered a new era of information exchange due to the widespread use of mobile devices andthe Android operating system is the most popularmobile operating system in the world. Simultaneously with applications, manymalicious applications with different purposes and forms for the Androidoperating system are being developed and released. Despite the increasing developmentof Iranian programs in software stores, it has never been investigated how muchof the malware is possible among them, that it may endanger the safety of usersor with other targets such as high volume of advertising, to offend users. For this reason, we decided tocreate models based on the static permission feature using a secure data setusing nine machine learning classifiers as well as a deep learning approach toclassify more than four hundred Iranian applications which wererandomly downloaded from the Cafe Bazaar store, in two categories: maliciousand Benign application. Then we will analyze the results and also by making allthe mentioned models on the samples downloaded from the Cafe Bazaar store, wewill complete our evaluations on the effect of the permission feature indetecting Iranian malware. Theresults obtained from the models made as well as the scanned samples downloadedfrom Cafe Bazaar store in the reputable site of Virus Total show that more thanfifty percent of the samples downloaded from Cafe Bazaar store are malware. Therefore, in order to increase theconfidence of Iranian users that the downloaded Android applications are notmalicious, the current approach to screening applications should bereconsidered before placing them in software stores.

   چكيده دانشكده و فضاهاي مرتبط با آن يكي از اقسام فضاهاي آموزشي است كه چگونگي فعاليت­هاي آموزشي با آن در ارتباط است. ازسوي­ديگر، آموزش و كارامدي آن در گرو اتخاذ و پياده­سازي روش­هاي آموزشي مناسب است. دروس فني من­جمله دروس ساختماني و سازه­اي يكي از بخش­هاي اصلي آموزش معماري در مقطع كارشناسي است. در دانشگاه رازي، پس از جابجايي گروه معماري از ساختمان قديمي آن به ساختمان جديد كه از آن با عنوان دانشكده هنر و معماري ياد مي­شود، گروه معماري با يك مسأله و يك پتانسيل مواجه شده است. مسأله آن است كه در شكل فعلي، فضايي براي دروس كارگاهي معماري ديده نشده است. اما پتانسيل آنكه، آتليه­هاي سابق معماري در ساختمان قديمي بلااستفاده است. علاوه­براين، ادبيات پژوهشي ايران در چندسال اخير به­دنبال كاوش و معرفي روش­هاي كارآمد آموزش سازه در معماري بوده است. لذا اين پايان­نامه سعي نموده با بازطراحي ساختمان قديمي و تبديل آن به مجموعه كارگاه­هاي دروس فني ساختماني و سازه­اي، بتواند از پتانسيل موجود درجهت حل مسأله اشاره­شده، استفاده كند. براين­مبنا، پايان­نامه از سه بخش تشكيل شده است. در بخش اول سعي شده روش­هاي آموزشي كارآمد در اين زمينه مشخص گردند. در بخش دوم در پي يافتن اقتضائات فضايي مناسب با آن شيوه­ها و در بخش سوم نيز درصدد بوده كه ساختمان مذكور را براساس اين الگوهاي آموزشي مناسب بازطراحي نمايد. نتايج بخش اول نشان داده كه مدل­سازي، روشي مناسب براي آموزش دروس فني ساختماني و سازه­اي است. لذا در بازطراحي ساختمان قديمي سعي شده، فضاهاي آموزشي مورد نياز با اين روش انطباق يابند.    كليد واژه­ها: آموزش، معماري، دروس فني، سازه، ساختمان، كارگاه

منابع انرژي تجديد­‌­پذير و استفاده از آن­ها در شبكه­هاي توزيع انرژي الكتريكي به ايجاد رويكرد­­­ها و ساختار­هاي جديدي منجر شده­است. قابليت مهم اين ساختارهاي جديد امكان بهره­برداري به صورت سيستم كنترل­پذير مستقل و مجزا از شبكه اصلي است كه با توسعه استفاده از مبدل­هاي الكترونيك­­قدرت امكان­پذير شده­است. از جمله اين ساختارها ريز شبكه مي­باشد كه يك شبكه­ي كوچك ولتاژ پايين يا ولتاژ متوسط است. ريزشبكه براي تغذيه يك مجموعه بار حساس محلي طراحي مي­شود. اجزاي ريزشبكه شامل منابع توليد پراكنده، بارهاي حساس و واحدهاي ذخيره­انرژي مي­باشد كه داراي دو حالت كاري متصل به شبكه و مستقل از شبكه (جزيره­ايي) است. در اين پايان­نامه ابتدا با شبيه­سازي ريزشبكه در حالت مستقل و با بكارگيري روش كنترل افتي از طريق اندازه­گيري ولتاژ و فركانس خروجي مبدل منبع ولتاژ (VSC) و اعمال حلقه كنترل توان اكتيو- ­فركانس، به مسأله تنظيم فركانسي مي­پردازد. براي كنترل فركانسي مهم­ترين بحث، كنترل توان اكتيو مي­باشد. پس از وقوع اغتشاشات عدم توانايي سيستم در حفظ فركانس در يك حد قابل قبولي منجر به عدم تعادل بين توليد و مصرف و در نهايت ناپايداري مي­شود. در حالت ناپايداري امكان دارد به صورت نوسانات ماندگار فركانس ظاهرگردد كه منجر به از مدار خارج شدن منابع توليدي و يا بارها مي­گردد. پايداري ديناميكي سيستم معمولا از طريق اينرسي انرژي جنبشي روتور در ماشين­هاي سنكرون تأمين مي­شود. سپس مبدل منبع ولتاژ با روش­هاي كنترلي ژنراتور سنكرون مجازي ( (VSG مجهز مي­شود، ويژگي­هاي ديناميكي هردو روش كنترلي افتي و ژنراتور سنكرون مجازي بررسي و براي نشان دادن تفاوت آنها در شرايط يكسان،­ هر دو روش كنترلي در حالت مستقل بررسي شده­اند. مدل­سازي سيگنال­كوچك براي مقايسه تغييرات فركانسي اين دو روش كنترلي انجام شده­است. يك روش كنترل افتي اينرسي مشابه ژنراتورسنكرون مجازي مطرح شده­است. تفاوت بين آنها اين است كه با شبيه­سازي معادله نوسان، روش كنترلي ژنراتور سنكرون مجازي داراي اينرسي مجازي است، در حالي كه روش كنترل افتي هيچ اينرسي ندارد. هدف اين طرح تنظيم فركانس و بهبود تقسيم توان با استفاده از اينرسي مجازي سيستم مي­باشد. بنابراين مي­توان بدون تغيير در سخت­افزار سيستم، اينرسي سيستم توان را با انرژي ذخيره شده در خازن­هاي لينك DC مبدل منبع ولتاژ افزايش داد و همچنين با تنظيم ولتاژ دوسر خازن پشيباني فركانس سيستم را فراهم و پايداري را بهبود نمود. به منظور دستيابي به اهداف پايان­نامه، دو اينورتر منبع ولتاژ به صورت موازي با يكديگر در نقطه اتصال مشترك به يك بار اهمي­سلفي متصل مي­شوند. از استراتژي كنترل ژنراتور سنكرون مجازي و تنظيم فركانس با   اينرسي مجازي خازن لينك DC در نرم­افزار متلب شبيه­سازي مي­شود.          واژه هاي كليدي­: ريزشبكه، منابع توليد پراكنده، كنترل افتي، مبدل منبع ولتاژ، ژنراتور سنكرون مجازي، اينرسي مجازي خازن لينك DC   

   Due to the increasing expansion of renewable energy sources in the world, the use of the concept of microgrid has been much considered by researchers. Microgrids are small distribution networks that can operate in both island and network-connected modes. Creating a suitable control platform for the best use of microgrids is of great importance. One of the problems regarding the use of renewable energy sources is the low level of inertia and the lack of inertia in these sources. Therefore, to overcome this problem, a concept called virtual synchronous generator has been introduced. Virtual synchronous generator using oscillation equation will help to create a virtual inertia to simulate behavior like real synchronous generator. In addition to this issue, another challenge that can be raised in this regard is the issue of voltage quality in microgrids. Different factors will cause unbalance.   In this Thesis we have tried to examine these problems. The possibility of switching on low voltage is one of the most basic needs of the network because during a voltage drop in the network, in fact, a series of incompatibilities will be formed between the active power output and the reactive power delivered to the network. By applying this scheme, which uses a proper power distribution between active and reactive capacities, it is possible to eliminate this voltage drop without any other faulty network specifications. In order to evaluate the correct operation of the network under voltage unbalance, the low voltage switching strategy (LVRT) and decouple dual synchronous reference frame (DDSRF) have been used. To prove the proposed method, a microgrid with two parallel distributed generation units is included in this work. Instead of the usual drop control that is often used in previous work, the concept of a virtual synchronous generator has been used alongside the LVRT strategy.

   امروزه استفاده از خودروها و وسايل نقليه عمومي كه به صورت تركيبي يا كامل از سيستم فتوولتائيك جهت تأمين انرژي استفاده مي‌نمايند بسيار رايج و متداول شده است. از سويي ديگر با توجه به پايين بودن راندمان و گران بودن سيستم‌هاي فتوولتائيك، بهره‌برداري بهينه از اين سيستم‌ها امري ضروري و لاينفك مي‌باشد. در نتيجه، مي‌بايست راهكاري اتخاذ نمود كه در هر شرايطي ماكزيم توان و راندمان را از سيستم‌هاي فتوولتائيك اتخاذ نمود. هزينه بالاي راه‌اندازي اوليه و نيز راندمان پايين تبديل انرژي از جمله معايب استفاده از سيستم‌هاي فتوولتائيك مي‌باشد. براي كاهش معايب فوق تلاش‌هاي بسياري انجام شده و در حال انجام است تا راندمان تبديل انرژي را با افزايش كيفيت سلول‌هاي خورشيدي و نيز دريافت حداكثر توان از سلول‌هاي خورشيدي افزايش دهند. مشخصه‌هاي سيستم‌هاي فتوولتائيك ذاتاً غيرخطي بوده و تابع پارامترهاي محيطي از جمله ميزان تابش، دماي محيط و بار متصل به آن است. لذا با انتخاب مناسب نقطه‌كار آرايه فتوولتائيك مي‌توان در شرايطي كه ميزان تابش و دما ثابت يا متغير است حداكثر توان را از آرايه فتوولتائيك دريافت نمود. تاكنون روش‌هاي بسياري جهت دريافت حداكثر توان از پنل‌هاي خورشيدي پيشنهاد شده است كه يكي از پركاربردترين روش‌هاي اخير در رديابي نقطه ماكزيمم توان سلول‌هاي فتوولتائيك استفاده از روش‌هاي فرا ابتكاري در تخمين نقاط اكسترمم تابع توان خروجي سيستم فتوولتائيك است. با اين وجود، در تمام اين روش‌ها به چالش اساسي متحرك بودن سلول فتوولتائيك و تغييرات سريع شرايط جوي پرداخته نشده است. در اين پروژه، پس از مطالعه مدل ديناميكي دقيق سلول‌هاي خورشيدي وسيستم فتوولتائيك در شرايط جوي متفاوت، يك روش   مبتني بر دريافت ماكزيمم توان به كمك يك الگوريتم هوشمند پيشنهاد مي‌شود كه توانايي دارد به طور پيوسته، سريع و پويا نقطه دريافت ماكزيمم توان خورشيدي در پنل‌هاي فتوولتائيك نصب شده بر روي خودروي در حال حركت با تغيير سريع تشعشع و دما در حالت جزئي سايه‌دار كه يكي از عواملي است كه ميزان دسترسي خورشيد را براي پنل‌هاي فتوولتائيك محدود مي‌سازد و باعث مي‌شود به همه سطوح پنل‌هاي فتوولتائيك تابش و دماي يكسان و يكنواخت نرسد را دنبال نمايد.

Abstract There are so many ways to control inverters such as pulse width modulation and space vector modulation that are so complicated. Predictive control has covered a wide variety of controllers which have emerged recently for power converters. The existing characteristics of systems such as time-discrete implementation of known power converters and drives,   high speed controllers and also the characteristics of power converters and drives like non-linear systems, limited switching states and other limitations has spontaneously   lead to use of predictive control. The fourth leg in three-phase inverters has boon provided for control the neutral current in unbalanced condition. In this essay, finite control set model predictive controller has been applied to a neutral point clamped inverter with both balanced and unbalanced performance, connected to linear and non-linear loads.The proposed method used discrete-time model and output filter to predict the must control parameters. The cost function uses the best switching state for the next sample time.After applying the swiching constraint to cost function and choosing the best switching frequency is obviously observed. It is also proved that with reducing the sample time in simulations, the total harmonic disorder reduced tool.For assessing the performance of proposed control method, it was done in some different sotuations namely linear and non-linear loads, balanced and unbalanced references. Key words: inverter. Three-phase inverter, three-level, predictive control, inverter control, NPC.   

The stability of the power system refers to the ability to maintain or return to the working point of the persistent state of the power system when it is disturbed. Turbulence may have a serious effect on the stability of the power system due to the stability of the small signal and the large signal. Increasing the consumption and diversity of consumers of electrical energy in power systems has led to an increase in the amount of energy transmitted in power systems. This increase has led to the interconnectedness of power systems to provide the required energy. In these interconnected systems, low frequency fluctuations can increase. These fluctuations affect the security and stability of large power systems and limit the current of power in the communication lines between the power sub-systems. Normally, synchronous generators maintain a constant vetting and a constant relative angle between stator and rotor coils, which is called synchronous generators in power systems. As soon as disturbances occur, the ability of the synchronum generator to balance the mechanical power of the turbine generator and the electrical power of the load to maintain stability is controlled. Traditionally, in the control of synchronous generators, a power system stabilizer (  ) produces an additional drive signal for the AVR excitation system to drive low frequency fluctuations. The goal is to create more mirant torque. On the other hand, installing    on all production units may lead to unwanted dynamic interactions. Matlab programming to combine probable load spreading analyses, linear modeling of multi-machine power system, small signal analysis and    optimization with pso metaheuristic algorithm for critical generator based on single-way stabilizers that have performance capability To have the best, it will be done.  

Today, electric vehicles are a suitable alternative to internal combustion vehicles due to their higher efficiency and far less environmental damage than internal combustion vehicles. But the factors that limit the use of these vehicles are issues such as the limitation of a city in having adequate communication routes and parking infrastructure and their charging stations. On the other hand, although the capacity of these vehicles alone is limited, a set of these electric vehicles at charging stations turns them into a unit that has the ability to appear in the role of a relatively large load for the network. Therefore, in order to make the best use of electricity distribution networks, it is necessary to operate and find the optimal location and capacity of charging stations for electric vehicles. In this regard, in this thesis, an attempt has been made to improve the IEEE 69_BUS TEST SYSTEM by determining the optimal location and capacity of electric vehicle charging stations based on the actual conditions of the power system.. For this purpose, uncertainty due to the number of vehicles in each charging station has been considered. The objective function in the present problem is multi-objective with the objectives of reducing losses (active and reactive) and reducing voltage deviation, which is optimized using the particle swarm algorithm and genetic algorithm in the MATLAB software platform and the results obtained from the location are compared.   

   در سالهاي اخير اهميت استفاده از مبدل­هاي الكترونيك قدرت به نحوي زياد شده است كه مقالات متعددي در اين زمينه به چاپ رسيده است. روشهاي متنوعي در كنترل مبدل­هاي قدرت ارائه شده است كه از رايج­ترين روش­ها مي­توان به مدلاسيون بردار فضايي، مدلاسيون پهناي پالس و ... اشاره نمود. در اين پايان نامه از روش كنترل پيش­بين مبتني بر مدل براي كنترل كننده يك اينورتر منبع ولتاژ سه­فاز چهارساق استفاده شده است. روش پيشنهادي در اين پايان­نامه با اعمال قيد كليدزني در طراحي كنترل­كننده باعث كاهش فركانس كليدزني مي­گردد كه تلفات ناشي از كليدزني را كاهش مي­دهد در عين حال باعث بهبود عملكرد سيستم در توان­هاي بالا و كاهش هزينه نهايي ساخت مبدل مي­گردد همچنين با استفاده از روش پيشنهادي در حالت كنترل پيش­بين دو مرحله­اي مي­توان زمان نمونه برداري سيستم را افزايش داد. علاوه­بر­اين مي­توان به مقاوم بودن كنترل­كننده پيشنهادي در تغييرات امپدانس خط اشاره نمود كه اعوجاج هارمونيكي كل سيستم در محدوده قابل قبولي قرار مي­گيرد. كه به‌منظور بررسي عملكرد صحيح روش پيشنهادي حالت‌هاي متعادلي و نامتعادلي سيستم موردمطالعه، در محيط سيمولينك نرم‌افزار متلب شبيه‌سازي گرديده است. واژه‌هاي كليدي: كنترل پيش‌بين ، اينورتر، ، كاهش فركانس كليدزني، قيد كليدزني، امپدانس خط

Ionic polymer metal composites (IPMCs) are a class of Electroactive Polymers that generate bending motions when they are subjected to an electric field. Very low mass and size, low driving voitage, large strain, flexibility and operation in wet conditions are advantages of an (PMC actuator over traditional actuators. Due to its complexity and its nonlinearity, the IPMC modeling is difficult and its behavior is still not fully agreed upon by researchers. In this thesis, fabrication, dynamic modeling and robust control of a strip type and helical shape IPMC actuator is presented. Dynamic model of a cantilever IPMC actuator based on a distributed RC electrical circuit is developed. The RC transmission lines theory is used to derive the simple analytical impedance and actuation model of an IPMC actuator. Considering the highly nonlinear and uncertain dynamics of the IPMC actuator, a feedback controller based on quantitative feedback theory (QFT) is designed to suppress the arbitrary external disturbances and consistently track desired input.

  Abstract: Today, due to the limited fossil fuels, environmental pollution, the transition from this fuels to renewable energy is inevitable. Among the renewable energies, solar and wind energy have received more attention due to better accessibility and higher capacity. Wind turbines with vertical and horizontal axis are used to exploit the wind power, which are more commonly used with horizontal axis wind turbines due to higher power extraction. The generators used in these turbines are also divided into two categories: constant speed and variable speed. Variable speed generators are more commonly used due to lower mechanical stress and higher efficiency. Among variable speed generators, DFIG is particularly important because of its unique advantages. These features include four-zone Active and Reactive Power Control, optimum performance at variable wind speeds, lower converter costs and reduced power losses and more. Today, due to the special structure of wind generators and the way they are controlled and connected to the grid, as well as issues such as variable wind speeds and uncertainties, the use of these generators faces particular problems. These include power generation control, maximum power point tracking, optimum performance at voltage and current unbalanced conditions. The wind turbine studied in this study is a doubly feed induction generator (DFIG) in which the stator is directly connected to the grid and the rotor coil is powered by a frequency converter consisting of two AC-DC converters based on a two-way IGBT controller and a DC link. Rotor-side converter with variable frequency injector plays the role of compensator for mechanical frequency difference with grid frequency. The grid side converter function is control of DC link voltage and in some cases provide reactive power. In this study, the performance and control design of a doubly fed induction generator is first evaluated in balance and then the DFIG generator is analyzed while the grid voltage is in unbalanced state. In a doubly fed induction generator, the unbalanced grid voltage causes the stator current, the rotor current to the converter, the current to the converter, torque and flux to be unbalanced. In this study, the stator and rotor currents are balanced by separating the positive and negative components in the unbalanced state of the grid voltage and negative sequence compensation. In the next step, the voltage of point of common coupling will be unbalanced because of the interruption of one of the three-phase load phases, using the static synchronous compensator (STATCOM) with the Decoupled Double Synchronous Reference Frame method (DDSRF) will be balanced and stabilized. In this study, MATLAB simulator software, which is a powerful software in this field, was used to analyze the system and model under study. By comparing the waveforms of the stator current, rotor, grid side converter and PCC point voltage obtained from the proposed control scheme and comparing it with the absence of control on the system, it can be concluded that the proposed design can guarantee the performance of doubly fed induction generator in different conditions. key words: doubly fed induction generator – unbalance voltage - negative sequence – current of stator - static synchronous compensator -   decoupled double synchronous reference frame

در اين پايان نامه يك مدل جهت تامين انرژي مورد نياز يك خانه هوشمند، شامل انرژي الكتريكي و انرژي حرارتي ارائه شده است. خانه مورد نظر متشكل از واحدهاي توليدكننده انرژي ميكروتوربين، بويلر و توربين بادي مي باشد. ميكروتوربين مورد استفاده در اين خانه داراي قابليت توليد هم زمان برق و حرارت (CHP) است. هم چنين ذخيره كننده هاي الكتريكي و حرارتي جهت مديريت بهتر انرژي در نظر گرفته شده است. لازم به ذكر است خانه هوشمند مورد نظر داراي تبادل دو طرفه با شبكه توزيع انرژي الكتريكي مي­باشد. سوخت مصرفي ميكروتوربين و بويلر گاز طبيعي و وظيفه بويلر تامين كردن كمبود انرژي حرارتي لازم جهت تامين بار حرارتي خانه مي باشد. مدل ارائه شده به برنامه­ريزي انرژي الكتريكي و حرارتي خروجي واحدها و مقدار انرژي مبادله با شبكه بالادستي با هدف كاهش هزينه هاي تامين انرژي خانه و با ارضاي قيود مورد نظر از جمله قيد ميزان آلودگي مي­باشد. خانه مورد نظر با قابليت اجراي برنامه پاسخگويي بار با هدف مسطح نمودن پروفيل انرژي الكتريكي مصرفي خانه و كاهش هزينه هاي تامين انرژي در نظر گرفته شده است. نتايج شبيه سازي نشان داد كه مدل ارائه شده جهت تامين انرژي الكتريكي و حرارتي مورد نياز خانه، توانايي كمينه نمودن هزينه تامين انرژي الكتريكي و حرارتي خانه با در نظر قيد ميزان آلودگي و برنامه پاسخگويي بار را دارد. در اين پايان نامه، جهت كمينه نمودن مقيد هزينه تامين انرژي خانه، از الگوريتم بهينه سازي ازدحام ذرات (PSO) استفاده شده است.

  Wastewater treatment plants are among the most important urban facilities, the quality parameters of inlet effluent to the treatment plant to determine the load of inlet pollution to the facility and the selection of the appropriate treatment system and the quality parameters of the outlet effluent. Ensuring environmental constraints and investigating the potential for reuse of wastewater must be constantly monitored and evaluated. Since systematic measurement of these indices is subject to limitations, providing highly accurate software sensors and acceptable generalization power for predicting qualitative indices is crucial. As a result, in recent decades, extensive studies have been done on the modeling and prediction of the aforementioned indicators and increasing the accuracy of existing methods. On the other hand, there is no research that investigates the role and performance of hybrid models in predicting qualitative parameters of effluent, comparing the accuracy of linear, nonlinear and hybrid models, investigating the effect of different pre-processing approaches on modeling accuracy, investigating the effect of pre-order. The processing and role of outliers in the accuracy of time series models is felt. Therefore, for the first time, the present study will examine these cases.

  Abstract:In this research, while considering the issue of host capacity in various dimensions, focused onthe harmonious hosting capacity of the power grid, including distributed resources, to maintainpower quality in power networks as one of the most important challenges of today's power gridsalong with power and network protection. In this paper, by presenting a simple and practicalalgorithm that observes the network harmonic constraints and the harmonic voltage limits of theDGs based on the standards defined for each local power grid (here in Iran), we were able to testthe observance of the above limitations in a system where power loading in It is estimated thatthe level of virtual power (network-capable power) can be estimated by each DG to increase itsproduction level in the network without causing harmful harmful effects. The virtual power ofthis network for a central generator of kVA 6 O, equivalent to 344 kilowatts, is a power plantwith a power plant capacity of 244 kw, the name of the wind farm.

Abstract Economic dispatch is one of the most important problems in operation of power systems. The purpose of the economic dispatch problems is to obtain the generation power units in a way that supplies the demanded loads (including electrical and thermal powers) and meet different constraints at minimum cost. On the other hand, with increasing pollutants and environmental pollution, concerns have been raised. For this reason, the economic emission dispatch problems, which are considered in both sides, are very important today. On the other hand, due to the failure of classical and mathematical methods, to solve these problems, considering the various restrictions of power system, due to the existence of local minimums, nonlinear, non-convex, and non-smooth of the problem, the use of evolutionary optimization methods has been increased. Therefore, in this thesis, ICA algorithm, hybridizing TVAC-PSO with EMA algorithm, and a new method based on fast non-dominated sorting and dynamic crowding distance are used to solve problems of CHPED, CEED, and also solving multi-objectives problems of CHPEED and DEED. In each case, each one is applied on several test systems and their results are compared with those obtained from other known methods, the results of which show the effectiveness and superiority of the proposed methods over other methods, in each of these fields. In addition, the statistical comparison results of the proposed new method prove its robustness and reliability. Also, a constraint handling technique, for the first time in the field, is integrated into the proposed hybrid algorithm, and its effectiveness in satisfying constraints at least cost compared to other methods is shown in constrained CEED problem. Finally, in order to evaluate the proposed hybrid algorithm in solving practical problems, a new dynamic multi-objective test system is introduced and solved by considering system practical constraints, such as ramp rate limit, prohibited operating zones, valve point loading effect, spinning reserve, transmission electrical losses and multi-fuel.Satisfaction of all of these constraints indicates the appropriateness of the procedure used in this algorithm. o Keywords: Economic Dispatch, Transmission Electrical Losses, Multi-fuel, Spinning Reserve, Valve Point Loading Effect, Prohibited Operating Zones, Constraint Handling, Dynamic Economic Emission Dispatch  

نظر به اينكه ويسكوزيته و نقطه ريزش نفت سنگين ميدان پايدار شرق بالا مي باشد، هدف از انجام اين پايان نامه پايين آوردن خصوصيات فوق با استفاده از فرايند Visbreaking مي باشد. در اين فرايند مولكولهاي سنگين هيدروكربني در اثر حرارت شكسته شده و به مولكولهاي كوچكتر تقسيم مي شوند. بسته به شرايط فرايندي، همواره بخشي از خوراك به هيدروكربنهاي سبكتر از بنزين و همچنين هيدروكربنهاي در محدوده نقطه جوش بنزين و گازوئيل نيز تبديل مي شود. نكته بسيار حائز اهميت در اين فرايند انتخاب مناسب شرايط عملياتي جهت به حداقل رساندن احتمال تشكيل كك مي باشد. بدين منظور در واحدهاي ارتقاي كيفيت نفت سنگين از دو فرايند كلي براي دستيابي به اهداف فوق الذكر استفاده مي شود كه عبارتند از Coil Visbreaking و Soaker Visbreaking. در ادامه هر كدام از اين روشها به طور مختصر توضيح داده مي شوند.

The density of the presence of small renewable resources, such as solar cells, fuel cells and small internal combustion engines, is increasing at day-to-day distribution levels. This increase in the presence of renewable energy sources in distribution systems has created a new structure called the micro-grid. A micro-grid is known as a small-size power system, consisting of distributed products, energy storage systems, and various types of electrical and thermal loads. For micro-grids, two major modes of operation are defined: network-connected mode and island mode. Micro-grids are normally operated as systems connected to the network, but can operate in island mode if network errors occur. The micro-grid control strategy includes PQ method in network-connected mode and v / f method in island mode. In this thesis, the aim of the project is to design the initial control consisting of droop controller in island mode and PQ controller in the network-connected grid, which consists of three distributed generation units, including solar cell, wind turbine and battery. After the design of the initial control to improve the performance and compensate the voltage drop caused by the control of the primary level, secondary control is used. In the designed controllers of secondary level, the optimal setting of compensating parameters is made. We use the PSO algorithm and robust control to adjust the compensator parameters. Finally, the results are analyzed and compared with each other.

بررسي قابليت اطمينان شبكه هوشمند با لحاظ نمودن خودترميمي شبكه در حضور منابع توليد پراكنده

  Energy storage systems (E  ) play a major role in power systems planning and operation. Regarding the continuing evolution of the storage technologies, the E   will be highly regarded in the future power networks, and also their various applications will be increased. The optimal E   allocation problems mean reducing the investment costs (or initial costs) as well as reducing the networks expected operation cost. By increasing the ESS capacity, the investment costs are increased, but the network operation cost is reduced; therefore, selecting inappropriate size and site for the E   would result in undesirable costs in the system. Among several advantages of the E  , improvement of the power system costs and voltage profile can be considered as the most prominent characteristics of the E  . Besides, increasing the renewable energy resources penetration, such as wind power, for reduction of the environmental pollution, postponed the construction of large and concentrated fossil-fuel power plants as well as transmission lines, increased complexity and harder distribution and its subsequent significant costs, improved power quality and increased reliability, and supply of the subscribers power demand at load peak times are some of other advantages of the use of E  . By using the E  , the generation power shortage resulted from disconnection of the existing units or separation of the renewable resources can be controlled; thus, the microgrids reliability criterion, especially in cases of high penetration of the renewable resources, is met. Simultaneous determination of size and site of the E   is a non-deterministic non-convex problem, which should be modeled in presence of the real constraints governing the power system. On this basis, in the present dissertation, for the first time, the optimal allocation problem of E   was investigated considering the practical constraints including generation and consumption balance, units generation power limitation, prohibited performance zones, ram   rate, as well as simultaneous reduction of three different and incompatible objective functions of cost, voltage deviation, and air Emission. Due to complexity of the problem, the presence of various constraints and incompatible objective functions, as well as possibility of involvement of the classical optimization methods in local points, from among the evolutionary optimization methods, two hybrid multi-objective algorithms known as MOGSA and MOPSO-NSGA-II were proposed. The modeling and formulation of the problem was performed in MATLAB software. In order to take the uncertainty into account, wind generation power was discretized using the five-point estimation method (5PEM), and the IEEE 30-bus standard system was selected for simulation. Furthermore, the multi-criteria decision-making techniques were used in order to increase accuracy and make sure of selection of the best solution from among the optimal solutions. The simulation results clearly show efficiency and effectiveness of the proposed method.

  The issue of   unit commitment is to determine the situation of switching on or off the available power generation units in a power grid. By solving this problem, the quantities of productive powers are determined economically, according to the existing constraints. One of the important criteria in solving the problem of orbiting unit commitment is to minimize the cost of electric power supply for the power system over a given time period. In recent years, the use of renewable energy for electrical energy has been given particular attention due to rising fossil fuel costs and also environmental problems caused by these fuels. On the other hand, , there are also some problems of the participation of these units in supplying demand for the network with the increased penetration of renewable energy sources in power systems. One of these problems is the uncertainty in the electrical energy produced by these units, and also the unavailability of these units in the hours of the day. The uncertain nature of the energy produced by renewable energy sources has led to a difference in the actual and projected output power of renewable unit commitment. Therefore, the combination of active units in planning in the circuit of the unit commitment in real time may be subject to changes that will remove the system from the performance at the optimal point. To overcome this problem, it is necessary to determine how the renewable energy sources participate in supplying the demanded load of network through the planning of unit commitment. Therefore, by reducing the uncertainty of the capacity of the production of renewable energy sources, the system can be brought closer to the optimal work point. Therefore, in order to compensate for the nature of periodic and incidence of renewable energy sources, electrical energy storage devices have been used in power systems. In fact, the purpose of using energy storage systems in power systems is to maximize the use of renewable energy sources. In this paper, the problem of the installation of unit commitment has been investigated, due to the many problems associated with the use of fossil fuels, with regard to the cost of pollution in the presence of renewable energy sources and energy storages. The MATLAB software, the Combination of the Genetic Algorithm and the Priority List Procedure with new use have been used to solve the problem in unit commitment. In this method, the initial population is produced in such a way that the supply and demand equivalence requirements and the minimum time down, the minimum time up of the units the constraints of the ramp rate, and the reduction of electrical power of units and the reserve of the spinining reserve erformed on the standard 10 units and 38 units. The results indicate that this process can help reduce the cost of the problem in the circuit of the unit commitment.

  Micro-grid is a small local network and consist of distributed generation resources and loads that is used to enhance the power quality and reliability for consumers in the functions that are connected or separated from the main network. Today, with the increase of small and big single-phase loads, the quality of the voltage in the Micro-grid is more importance than before. One of the common issues in analysis of voltage quality is unbalanced voltages. Unbalanced voltages has several factors, most of these factors occur due to unbalance loads. In this research, the voltage unbalanced factor and their effects on the micro-grid facilities is described. Then, in order to voltage unbalance intensity evaluation, various indices and standards of voltage unbalanced are considered. The proposed scheme in this thesis, describes the voltage balancing and analysis of inverter- based distributed generation systems. The control scheme used to compensate unbalanced voltage due to unbalanced load in three-wire three-phase micro-grid is an extraction of positive and negative components of both voltage and current using d-q axis for inverter-based voltage sources during the occurrence of unbalance in the micro-grid. This scheme is used to compensate unbalanced voltages in the point of common coupling. The purpose of this design is to control the positive and negative components of the voltage separately and generate reference currents. Because micro-grid are used in the grid-connected and island mode, so their controller method is considered in this two mode too. The control of output power of each of dispersed generation units in the both grid-connected and island mode is done with the Droop Control. At the end, in order to improve the performance of the controllers, the coefficients of these controllers are optimized so as to minimize the current error using the online Particle Swarm Optimization (PSO) algorithm. That one of the benefits online method is to resolve the uncertainty problem of system parameters. In order to verify the proper performance of the control system, a micro-grid with two voltage source converters (VSCs), unbalanced local load and network are simulated with the MATLAB/SIMULINK and grid-connected and island mode are investigated.

New modern world intensively needs high quality and reliable electricity energy. Distributed Generation (DG) resources are one of the best choices for electricity energy provision. Whereas use of distributed generation resources provides feasibility of implementation of hierarchical control on small grids alike big grids, electrical energy distribution grids that comprising distributed generation resources are known as Microgrids. Microgrids usually are used in grid connected mode but if fault occurs in grid or when improvement of load power’s quality is need, they can work in islanded mode. Because of presence of 1 phase loads and 1 phase resources such as solar cells, microgrids’s voltage aren’t balanced. Voltage unbalancing causes decrease of electrical energy’s quality, increase of losses and decrease of microgrids’s stability. So proposition of suitable control solution for unbalancing voltage compensation is very important. In this thesis we want to compensate voltage unbalancing in Point of Common Coupling (PCC) in presence of 1 phase unbalanced load for both grid connected and islanded modes because voltage unbalancing might causes diturbtion and makes problems for sensitive loads. For voltage unbalancing compensation usually two decoupled control loop are used for positive and negative sequences. This structure is known as Double Synchronous Reference Frame (DSRF). In this thesis for improvement of current and voltage DSRF controller’s performance and elimination of oscillations in unbalanced voltage condition, Decoupled Double Synchronous Reference Frame (DDSRF) has used. The method is in such a way that oscillation’s amplitude and phase is estimated and implemented to DSRF. So oscillating couple between positive and negative current control loops and between positive and negative voltage control loops are eliminated and it causes of unbalancing voltage of PCC in both grid connected and islanded modes.

<  gt;ارائه الگوريتمي براي جداسازي جريان هجومي از جريان هاي خطاي خارجي ترانسفورماتور</P>

Power transformers are one of the most valuable equipment in power systems in which fault occurrence may cause severe damages and significant decrease of network reliability. Moreover, winding and terminal faults include more than 70% of occurred faults in power transformers. One of the various type of winding fault is inter-turn fault. As a rule, most of the protection systems do not detect the inter-turn fault at the beginning of occurrence. Therefore, this fault spreads to more turns and finally leads to main damages. There are different methods and algorithms to determine this kind of fault and each of them has particular advantages, disadvantages and uncertainties. In this thesis, the behavior of a Y-Y connection transformer during inter-turn fault has been investigated through simulation in Maxwell software and an online, fast, simple and also sensitive method is introduced based on the results and transformer equations. This method which is based on primary and secondary earth-fault current differential is capable to determine inter-turn fault (1% of entire winding) in various conditions such as full load, no load or even load unbalance. Two more common methods (Park Vector and negative sequence current) have also been simulated in order to compare to this method and the results are compared together. The introduced method in this thesis can be used to protect transformer in time of inter-turn fault.   

  A challenge of power transformers is mechanical faults occurred in windings, which may leave catastrophic effects in case of non-detection. Frequency response analysis, or transfer function method, is a powerful technique for monitoring power transformers, which can greatly help to increase the lifetime of the transformer and reliability in the power grid. A transformer may pass during severe short-circuit currents operation due to various power grid faults. One of the most serious problems with an in-service transformer is movement of its windings due to electromagnetic forces generated during short-circuit faults. Reduction of clamping pressure due to insulation aging can also cause winding movement and may result in an explosion. One of the methods for detecting the mechanical defects of the transformer is the frequency response analysis. Recent studies concentrated on the effects of various errors on the frequency response of the transformer. In order to study the effect of different deformation scenarios, transformer models have been developed. An accurate enough transformer model is required to study the various parameters on Frequency response analysis. Unfortunatly some of the parameters of the detailed model are frequency dependent. A detailed model is used to simulate transformer behavior especially in high frequency transients. This model was seen to be accurate enough to simulate frequency response of the transformer. Unfortunately some parameters of the transformer model are frequency dependent due to skin effect or proximity. Among this parameters the coil series resistance was seen to be more frequency dependent and in this thesis it has been shown that this factor affects different indices of the different transfer functions differently. Four transfer function used rather more in different papers and standards were derived to investigate the effect of frequency depended series resistance on them. Detailed transformer model parameters are derive from 3 dimentional transformer simulation in Maxwell software.

بهينه سازي كنترل كننده ها توسط الگوريتم بهينه سازي فاخته دريك ريز شبكه تركيبي درحضور چرخ طيار به منظور كنترل فركانس

<  gt;بهبود پايداري ريز شبكه هاي شامل توربوژنراتورهاي بادي با استفاده از اينرسي مجازي وكنترل مقاوم</P>

  The Electromagnetic Aircraft Launch System (EMALS) is being developed, electrical and electronic technologies, to replace the existing steam catapult on naval carriers. Recently, the double-sided linear launcher has attracted more and more attention from researchers. This paper presents utilizing the design and analysis of the Linear Hybrid Reluctance Motor (LHRM). This new motor is characterized by a stator formed by a combination of independent magnetic structures, each one composed of an electromagnet, the magnetic core with one or several coils wound on it, associated with a permanent magnet disposed between their poles. The rotor has the same configuration of a switched reluctance motor (SRM) without any coil, magnets, or squirrel cage. In order to improve the thrust characteristics of LHRM, the structural characteristics and magnetic field are analyzed. The initial design, the finite element analysis (FEA) is presented to obtain the magnetic cogging force and thrust force. Then Using FEA, the effects of the parameters on the thrust and thrust ripple waveforms is analyzed.

تحليل تاثير نانو ذرات خاك رس بر روي استحكام استاتيكي يك ورق پليمري

تحليل ديناميكي تير مدرج هدفمند باخاصيت پيزو‌الكتريكي تحت بار مكانيكي والكتريكي با روش اجزا محدود

Predictive control is known as a wide class of controllers that have found recent application in the control of power converters. The main characteristic of model predictive control (MPC) is the use of the system for prediction of the future behavior of the controlled variables over a prediction horizon. This information is used by the MPC control strategy to provide the control actions for the system by optimizing a predefined. This thesis presents a current control strategy using Finite Control Set Model Predictive Control (FCS-MPC) that applied to a three phase four leg voltage source inverter. This control scheme predicts the future load currents behavior for each valid switching state of the inverter. The control method chooses a switching state that minimizes the error between the output currents and their references. Also, in the following, a new method is proposed to reduce the amount of calculation. Finally, simulation results in Simulink/Matlab are demonstrated.  

  analyzing THE SMART BUILDINGS ON THE LOSS REDUCTION AND IMPROVING THE VOLTAGE PROFILE APPLYING TLBO