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Design of an Inner Current Control Loop for a High-Voltage Pulsed Power Supply to Reduce Inverter Current Stress
, M.Sc. Thesis Sharif University of Technology ; Kaboli, Shahriyar (Supervisor)
Abstract
A power supply is an important part of every electrical system. It matches the energy from the main source to the needs of the load and must provide the correct voltage waveform and power for proper operation. In applications where the load works at high voltage and high power, pulse power supplies are needed to deliver a short high-power pulse with lower energy use. In this method, energy is stored in capacitors for a long time and then released to the load in a short moment. In this study, the load is a magnetron lamp, which needs high-quality voltage and power pulses for correct operation. To keep this quality, the output of the pulse power supply must be controlled accurately. After the...
Blind Speech Separation in Convolutive Mixtures
, M.Sc. Thesis Sharif University of Technology ; Babaiezadeh Malmiri, Massoud (Supervisor)
Abstract
Blind Source Separation (BSS) aims to recover multiple source signals from mixtures without prior knowledge of the sources or the mixing process. This manuscript focuses on speech separation in convolutive mixtures, aiming to recover speech signals from mixtures that are linear combinations of the filtered versions of original signals. Most recent methods for blind source separation in both instantaneous and convolutive mixtures typically involve transforming time-domain mixed signals into the time-frequency domain using Short-Time Fourier Transform (STFT) and conducting the separation in this domain. Broadly, the separation process is followed by two main approaches. The first involves...
Modeling and technical-economic optimization of electricity supply network by three photovoltaic systems
, Article Journal of Solar Energy Engineering, Transactions of the ASME ; Vol. 136, issue. 2 , 2014 ; ISSN: 0199-6231 ; Khodaparast, P ; Kateb, M ; Sharif University of Technology
2014
Abstract
To attain an ongoing electricity economy, developing novel widespread electricity supply systems based on diverse energy resources are critically important. Several photovoltaic (PV) technologies exist, which cause various pathways to produce electricity from solar energy. This paper evaluates the competition between three influential solar technologies based on photovoltaic technique to find the optimal pathways for satisfying the electricity demand: (1) multicrystalline silicon; (2) copper, indium, gallium, and selenium (CIGS); and (3) multijunction. Besides the technical factors, there are other effective parameters such as cost, operability, feasibility, and capacity that should be...
Evaluation of energy recovery and potential of hydrogen production in Iranian natural gas transmission network
, Article Energy Policy ; Volume 61 , 2013 , Pages 65-77 ; 03014215 (ISSN) ; Saboohi, Y ; Kateb, M ; Sharif University of Technology
2013
Abstract
In the natural gas transmission network, from supply points to demand nods there are various technological options that include processing, transportation, conversion and gas distribution. Comprehensive analysis of natural gas network requires evaluation of different chains of gas flow through various levels based on economical and environmental criteria subject to technical and operational constraints such as feasibility, operability and reliability of different alternatives. To aid decision-making process in the sector of natural gas, a generic optimization-based model has been developed for assessing long term energy issues related to planning and design of natural gas supply systems. The...
ZnO-PEDOT core-shell nanowires: An ultrafast, high contrast and transparent electrochromic display
, Article Solar Energy Materials and Solar Cells ; Volume 145 , 2016 , Pages 200-205 ; 09270248 (ISSN) ; Safarian, S ; Kolahdouz, M ; Fathipour, M ; Ahamdi, V ; Sharif University of Technology
Elsevier
2016
Abstract
We report fabrication of ultrafast and high contrast transparent electrochromic device desired for display application using nanostructured electrode. To this end, poly (3,4-ethylenedioxythiophene) (PEDOT) nanotubes were synthesized by simple electrochemical polymerization method on hydrothermally grown ZnO nanowires array as electrode. The PEDOT nanotubes of 20 nm average wall thickness characterized by SEM, TEM and EDS. The manufactured cell was subjected to electrochemical test and spectrophotometery that showed high contrast of 54% during ultrafast switching time of <2.2 ms. In addition, high coloration efficiency of 234 cm2/C, ultrahigh diffusion coefficient of 2.01×10-4 cm2/s and...