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Total 132 records

    Building energy modeling with OpenStudio : a practical guide for students

    , Book Brackney, Larry ; Parker, Andrew ; Macumber, Daniel
    Springer International Publishing AG  2018

    Feasibility Study and Conceptual Design of Solar Energy Source for Surface Train System

    , M.Sc. Thesis Sharif University of Technology Maleki, Sina (Author) ; Durali, Mohammad (Supervisor)
    Abstract
    Advancements in solar powered systems bring about the possibility for today’s transportation systems to be operated and driven by such a clean and renewable source of energy. The challenging point of this combination is to draw high power levels from such a low power density source of energy. As a result, employing an efficient power storage and management system becomes inventible. The subjects of this research are to design a grid connected system and evaluate its performance and feasibility in a real application (Tehran- Mehrshahr surface train – Tehran 5th Metro Line). The task includes sixteen pairs of DC transmission lines which are powered by CIGS solar module technology and four... 

    Design and Implement of Voltage Ripple Measuring System for Power Supply of Microwave Tubes

    , M.Sc. Thesis Sharif University of Technology Ahmadi Someh, Saeed (Author) ; Kaboli, Shahryar (Supervisor)
    Abstract
    Mostly, the high voltage DC power supplies have output voltage ripple. In such an applications like power supply of microwave lamps in radar systems, low output voltage ripple is an important point of operational characteristics. On the other hand, measuring the low voltage ripple will be a challenge that can lead to recognize of its reasons and reduce its amplitude. In this thesis, different ways of ripple measurement constraints is described, then a method based on high pass filters for output voltage ripple measurement is implemented. The impact of components tolerance and their parasitic components like shunt parasitic resistance of a capacitor in filter operational characteristics is... 

    Probabilistic Safety Assessment of IR-360 for Station BlackOut Accident (SBO) and Determination of the Frequency of Occurrence

    , M.Sc. Thesis Sharif University of Technology Moinian, Fatemeh (Author) ; Ghofrani, Mohammad Bagher (Supervisor) ; Yousefpour, Faramarz (Supervisor) ; Karimi, Kave (Co-Advisor)
    Abstract
    Station Blackout (SBO) involves Loss of Offsite Power (LOOP) concurrent with failure of the onsiteemergency ac power system. Although SBO is a beyond designbasis accident, in recent years this accident attracts a lot of attention. Fukushima nuclear accident which was initiated by earthquake followedby tsunami led to a SBO accident. In this thesis, Probabilistic Safety Assessment (PSA) is applied to analyze SBO in IR-360 nuclear power plant and to compute its frequency. Meanwhile, weak points of the plant are identified in order to minimize the SBOprobability of occurrence. Fault tree method is used to evaluate emergency power system and offsite power system reliabilities. Common Cause... 

    Application of PSA Methods in the Reliability Analysis of EPSS of Busherhr NPP in case of Station Black Out

    , M.Sc. Thesis Sharif University of Technology Khorrami, Vahid (Author) ; Ghofrani, Mohammad Bagher (Supervisor)
    Abstract
    LOOP accident is one of the most important accidents in NPPS and it leads to loss of power supply of the RCP pumps which are the main pumps of primary circuit. Subsequently trip of the rector occurs. In safety analysis, concerning worst conditions, assumes that after a small period of time, main generator of plant stops working and loss of AC power supply of all power plant loads including safety systems ocures. To control of this accident, it’s necessary to startup and load backup power supply system (EDGs) for at least one safety channels, if not, the accident moves forwards and becomes S.B.O accident which is more important accident that ends to core damage because of stops working of all... 

    Holistic Energy Management in Distributed Data Center with Renewable Energy

    , Ph.D. Dissertation Sharif University of Technology Taheri, Somayyeh (Author) ; Goudarzi, Maziar (Supervisor)
    Abstract
    In recent years, and with the development of information technology in various aspects of life, the growth of energy consumption in this sector has accelerated. With the advent of cloud computing and the development of its users, data centers have become one of the largest consumers of energy in the world. Adverse effects of fossil fuel consumption on the one hand and the global energy crisis as a limiting factor for development, on the other hand, have doubled the importance of managing the issue and reducing energy consumption in this sector. The two main energy-related concerns in data center construction are clean energy and energy management. The use of new energy and natural facilities... 

    Energy-Aware Service Job Scheduling in Data Center with Distributed UPS and Renewable Energy

    , M.Sc. Thesis Sharif University of Technology Ranjbar, Behnaz (Author) ; Goudarzi, Maziar (Supervisor)
    Abstract
    Recently, The Earth has become warm rapidly over the past few years. This global warming is not only caused by natural phenomena, and further increased by humans and the amount of greenhouse gases in the atmosphere. Around 40 to 50 percent of energy consumption is related to information technology and communications. However, the rapid growth of electricity consumption in data centers, in addition to increased costs, data center challenges faced serious environmental pollution and more greenhouse gases. Use of renewable energy and reducing electricity costs in data centers are the important subjects for researchers around the world. Many researchers provide solutions to reduce environmental... 

    Improving Renewable Energy Usage in Data Centers with Distributed UPS Using Batch Job Scheduling

    , M.Sc. Thesis Sharif University of Technology Haghshenas, Kawsar (Author) ; Goudarzi, Maziar (Supervisor)
    Abstract
    In recent years, the demands come to data centers have increased significantly, so huge amount of energy consumption, cost of this usage and environmental effects of data centers have become serious issues. Accordingly using solar energy to provide some portion of a data center’s energy usage can reduce environmental effects efficiently. Also smarter use of this energy could decrease overall cost of energy in data center. The demands that come to a data center are categorized to critical and non-critical workloads. Running of Non-critical workload (batch job) can be moved to another time according to its deadline. This work suggests a solution that schedules batch jobs considering solar... 

    Sensorless Estimation of Lifetime of High-Voltage Power Supplies

    , M.Sc. Thesis Sharif University of Technology Sheikhi Azizi, Abbas (Author) ; Kaboli, Shahriyar (Supervisor)
    Abstract
    High voltage power supplies have a wide range of applications, and due to their high cost, it is essential to monitor their condition to predict potential failures and prevent significant losses. The most common cause of power supply failure is the wear and tear of its components. However, these components can be replaced before they wear out completely to prevent the failure of the power supply and, consequently, avoid damaging the load. Estimating the lifetime of power supplies is crucial because it allows for scheduled maintenance and helps prevent significant problems in power supplies. By estimating the lifespan of a power supply, one can anticipate when it may fail, allowing for the... 

    Reducing the Flow Rate of Short Circuit Fault Current at the Output of the High Voltage Power Supply

    , M.Sc. Thesis Sharif University of Technology Zibarzani, Ali (Author) ; Kaboli, Shahriar (Supervisor)
    Abstract
    In this research, we have presented a method to delay the propagation of fault current in high voltage power supplies. Common protection methods usually protect the load and do not protect the power supply itself well. In this research, our goal was to propose a method to prevent the short circuit fault current from reaching the power supply elements. At first, the available methods to limit the fault current and protect the high voltage power sources were studied and investigated. Then, using the transmission line theory, a ladder filter was designed as an alternative to the normal filter at the output of the power supply. In the next step, using software simulation, the performance of the... 

    Hardware Design for Cold Plasma Characterization Chamber

    , M.Sc. Thesis Sharif University of Technology Aghapour, Reza (Author) ; Rashidian, Bijan (Supervisor) ; Faez, Rahim (Supervisor)
    Abstract
    Cold plasma due to its special properties has many applications in the microelectronics industry. At the beginning of this study, a few examples of widely used plasmas and the requirements for driving their power sources have been investigated. To generate and characterize plasma, various topologies of DC power supply construction, including high-voltage low-current power supplies called multipliers and low-voltage high-voltage power supplies called converters, have been reviewed and compared.Circuit for pulse generating for plasma application has also been proposed and investigated. In the simulation section, after introducing, reviewing, and compareing the common types of simulators, the... 

    Improving the Direct Switching Method for High Voltage Applications to Improve the Load Voltage Waveform

    , Ph.D. Dissertation Sharif University of Technology Zarghani, Mostafa (Author) ; Kaboli, Shahriyar (Supervisor)
    Abstract
    Pulsed power supplies are used in linear accelerators, pulsed lasers, nuclear welding, radar, some medical applications, etc. which require much more instantaneous power than average power. These sources store energy in an energy storage element for a relatively long period of time and then release this energy in a short period of time. Among the most important goals pursued in these power supplies are the quality of the output pulse, the reliability and lifetime, efficiency, and cost, which depending on their application, some of these features are more important. One of the important applications of pulsed wave power supplies is their use to power microwave lamps. In some applications of... 

    Analysis of Output Voltage Power Spectrum of High Voltage Power Supply

    , M.Sc. Thesis Sharif University of Technology Nouri Jevinani, Hadi (Author) ; Kaboli, Shahriyar (Supervisor)
    Abstract
    Some microwave tubes can function as a narrowband power amplifier and their output power spectrum is an indicator of their amplification and efficiency. One of the factors affecting its power spectrum is the noise and ripple of its HVDC power supply. To reduce the negative effects of power supply, first there should be an exact measurement of ripple and noise in the output of the HVDC power supply. Destructive factors which affect voltage ripple measurement in the case of high DC voltage are follows as conductive interference, radiative interference, intrinsic noise of electrical elements, and nonideal frequency response of voltage divider. After identifying and suppressing the mentioned... 

    Design of Excitation Circuits for Cold Plasma Characterization Chamber

    , M.Sc. Thesis Sharif University of Technology Vardast, Sajjad (Author) ; Rashidian, Bijan (Supervisor)
    Abstract
    Plasma is a quasi-neutral gas consist of charged and neutral particles that manifest collective behavior. Plasma is an ionized gas in which all or a significant portion of its atoms have lost one or more electrons and become a set of positive ions and electrons. Plasma is one of the four primary states of matter. This project intends to generate plasma by a pulsed electric discharge in a gaseous environment. At first, in this project, the proper excitation circuits are collected and compared, then based on the feasibility of production, applicable methods are selected and constructed. The construction steps were such that the selected circuits were first simulated with the appropriate... 

    Improving the Performormance of an Ultra Narrow Pulse Generator based on Transmission Lines

    , M.Sc. Thesis Sharif University of Technology Toliat, Ali (Author) ; Kaboli, Shahryar (Supervisor)
    Abstract
    The ultra-narrow pulse generator have being used for direct production of pulsed power. One of these structures is being used to make a bipolar pulse and its main feature is the utilization of the real transmission lines (not PFN) with an intricate structure that caused volume to be compressed. It is desired to reach an appropriate design by analyzing the output waveform and its relation to the transmission line parameters. A little piece of work has been done in the past but there were some differences from our anticipations in the waveforms, like pre-pulse, long rise and fall times and overshoot that caused by some non-idealities in the structure. What we have done in this project is to... 

    Design and Implementation of a Regenerative Programmable Voltage Source

    , M.Sc. Thesis Sharif University of Technology Ghasemizadeh, Roozbeh (Author) ; Zolghadri, Mohammad Reza (Supervisor)
    Abstract
    Programmable AC Power Supply is a part of any Grid Simulator. Grid simulator is a system that, as a voltage source, can produce various power grid voltage waveforms in the output, and as a load, can draw different currents of ordinary loads from the power grid. The application of Grid Simulators is testing many grid connected systems, such as chargers, power supplies, PV inverters and etc. The purpose of this thesis is to design and build a 3 kW Programmable AC power supply, which can be used as a part of a grid simulator in future works. In this thesis, back to back converter topology is used for implementation of the programmable AC power supply. This back to back converter consists of an... 

    Control of Three-phase UPS with Nonlinear Load Using Disturbance Observer Considering Transformer Concerns

    , M.Sc. Thesis Sharif University of Technology Shahriari, Zohair (Author) ; Tahami, Farzad (Supervisor)
    Abstract
    Nowadays, non-linear loads comprise an important part of electrical grids. One of the most essential sources of nonlinear loads is switching power supplies, which mainly include power electronic rectifiers. When power outage occurs, Uninterruptible Power Supplies (UPS) must be able to supply these loads. The nonlinearity of the load has a significant effect on the Total Harmonic Distortion (THD) of the output voltage, which may not be easily reduced, especially in three-phase inverters. Furthermore, the presence of isolating transformers in these power supplies limits the control of harmonics and intensifies the nonlinear effects of the system.In this Master Thesis, a disturbance observer is... 

    Robusting Series Structure of Semiconductor Switches for High Voltage Applications

    , Ph.D. Dissertation Sharif University of Technology Mohsenzadeh Hedesh, Sadegh (Author) ; Kaboli, Shahriyar (Supervisor)
    Abstract
    The series structure of semiconductor devices has a wide application in the industry and research field. The most critical issue in the series structure of series switches is the safe operating condition provision. Hence many kinds of research have been intensively focused on this topic to overcome this necessity. However, many existing aspects relevant to the series stacking of the semiconductor switches have not been pointed out. These include, the power loss must be accepted for the series devices and recovery of this power, providing balanced voltage for the series devices through a simple and easy implementing structure and providing a safe voltage condition for the series devices under... 

    Analysis and Improvement of Output Voltage Ripple in High Voltage DC Power Supply

    , M.Sc. Thesis Sharif University of Technology Ziaoddini, Mojtaba (Author) ; Kaboli, Shahryar (Supervisor)
    Abstract
    The TWT is highly sensitive to the ripple amplitude of its power supply output voltage. If the amplitude of the output voltage's ripple exceeds a certain limit, the amplitude of the undesired harmonics in the power spectrum of the TWT is greatly increased. Increasing the amplitude of undesired harmonics in the TWT output power spectrum reduces the accuracy and performance of the TWT. Therefore, for optimum TWT performance, a low-ripple power supply is essential. Typically, a low-frequency rectifier or high-frequency switching structure is used to build a high-voltage DC power supply. In this thesis, the different structures of high voltage DC power supplies are studied. Next, by focusing on... 

    Reliability Improvement of the High Voltage Power Supply Based on Interleaved Inverters

    , M.Sc. Thesis Sharif University of Technology Keshtkar Teeula, Afshin (Author) ; Kaboli, Shahriyar (Supervisor)
    Abstract
    In some high voltage applications it is necessary for high voltage power supply (HVPS) to operate over a wide load and gain range. For instance a HVPS may be used to supply various microwave tubes. Our goal in this thesis is to design a HVPS which can provide a DC voltage between 0-15 KV and 0-5 KW. In convetional approaches, operating over wide load and gain range necessitates the switching frequency or duty cycle to swing over a wide range. This approach may disturb soft switching, consequently switching loss will increase. The control process will be more complex too. the wide swing range of switching frequency means that the HVPS needs to operate with low switching frequency too....