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power-supplies
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Control of Three-phase UPS with Nonlinear Load Using Disturbance Observer Considering Transformer Concerns
, M.Sc. Thesis Sharif University of Technology ; 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...
A new self-powered electromagnetic damper for structural vibration control
, Article Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2017, 26 March 2017 through 29 March 2017 ; Volume 10168 , 2017 ; 0277786X (ISSN); 9781510608214 (ISBN) ; Chang, C. C ; Fiberguide Industries; Frontiers Media; OZ Optics, Ltd.; Polytec, Inc.; The Society of Photo-Optical Instrumentation Engineers (SPIE) ; Sharif University of Technology
SPIE
2017
Abstract
This paper presents a new self-powered hybrid electromagnetic damper that can mitigate vibration of a structure. The damper is able to switch between a power-regenerative passive mode and a semi-active mode depending on the power demand and capacity. The energy harvested in the passive mode due to suppression of vibration is employed to power up the sensing and electronic components necessary for the semi-active control. This provides a hybrid control capability that is autonomous in terms of its power requirement. The device mechanism and the circuitry that can realize this self-powered electromagnetic damper are described in this paper. The parameters that determine the device feasible...
Investigating power outage effects on reliability of solid-state drives
, Article Proceedings of the 2018 Design, Automation and Test in Europe Conference and Exhibition ; Volume 2018-January , 2018 , Pages 207-212 ; 9783981926316 (ISBN) ; Taheri, F ; Lotfi, M ; Karimi, M ; Asadi, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Solid-State Drives (SSDs) are recently employed in enterprise servers and high-end storage systems in order to enhance performance of storage subsystem. Although employing high speed SSDs in the storage subsystems can significantly improve system performance, it comes with significant reliability threat for write operations upon power failures. In this paper, we present a comprehensive analysis investigating the impact of workload dependent parameters on the reliability of SSDs under power failure for variety of SSDs (from top manufacturers). To this end, we first develop a platform to perform two important features required for study: A) a realistic fault injection into the SSD in the...
n the calculation of the leakage inductance in transformers with nonideal windings
, Article IEEE Transactions on Power Electronics ; Volume 35, Issue 8 , 2020 , Pages 8460-8471 ; Mohsenzade, S ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
The transformer leakage inductance (TLI) is an important parameter in the design phase of the isolated power supplies. Hence, the TLI estimation before the transformer construction is very useful for the designers. The previous works considered an ordered winding turn arrangement (WTA) for the transformers. This assumption considers only ideal windings which may result in a significant error from what will be achieved after the construction of the transformer. This article concentrates on the transformers with nonideal windings in which the turns are not ordered. The uneven distribution of the turns in the layers is mainly due to the wrapping machine error. Hence, for a specific transformer...
Customer choice of reliability in spinning reserve procurement and cost allocation
, Article 2008 IEEE Electrical Power and Energy Conference - Energy Innovation, Vancouver, BC, 6 October 2008 through 7 October 2008 ; January , 2008 ; 9781424428953 (ISBN) ; Fotuhi Firuzabad, M ; Sharif University of Technology
2008
Abstract
Reliability is one of the main factors influencing customer loyalty in a competitive power industry. The system operator must ensure that there is sufficient spinning reserve to maintain system security. Contractually such commodity requires a willing buyer and a willing seller. A novel pool-based market clearing algorithm for spinning reserve procurement and the cost allocation associated with provision of spinning reserve among DisCos is developed in this paper. Rational buyer model is used for energy and reserve market model. In the proposed algorithm, generating units bid simultaneously to energy and spinning reserve markets and these markets are sequentially cleared. In such a market,...
A voltage balancing scheme for series igbts to increase their expected lifetime in pulsed load applications
, Article IEEE Journal of Emerging and Selected Topics in Power Electronics ; Volume 9, Issue 1 , 2021 , Pages 461-471 ; 21686777 (ISSN) ; Zarghani, M ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
Clamp mode resistor capacitor diode (CMRCD) snubbers have a simple and easy implementing structure. They have been widely adopted in the pulsed power supplies to provide a safe operating condition for the series insulated gate bipolar transistors (IGBTs). The main problem of the CMRCD snubbers is their poor performance in the voltage balancing of the series IGBTs. They are essentially overvoltage protectors and clamp the voltage of the IGBTs in a probable potentially dangerous condition. This issue diminishes the expected lifetime of the series IGBTs, where a number of them face a higher level of the voltage than that of the others. The unbalanced voltage of the series IGBTs will result in a...
Investigation of transient effects on FPGA-based embedded systems
, Article ICESS 2005 - 2nd International Conference on Embedded Software and Systems, Xian, 16 December 2005 through 18 December 2005 ; Volume 2005 , 2005 , Pages 231-236 ; 0769525121 (ISBN); 9780769525129 (ISBN) ; Miremadi, S. G ; Zarandi, H. R ; Sharif University of Technology
2005
Abstract
In this paper, we present an experimental evaluation of transient effects on an embedded system which uses SRAM-based FPGAs. A total of 7500 transient faults were injected into the target FPGA using Power Supply Disturbances (PSD) and a simple 8-bit microprocessor was implemented on the FPGA as the testbench. The results show that nearly 64 percent of faults cause system failures and about 63 percent of the faults lead to corruption of the configuration data of the FPGA chip. © 2005 IEEE
Experimental evaluation of transient effects on SRAM-based FPGA chips
, Article 17th 2005 International Conference on Microelectronics, ICM 2005, Islamabad, 13 December 2005 through 15 December 2005 ; Volume 2005 , 2005 , Pages 251-255 ; 0780392620 (ISBN); 9780780392625 (ISBN) ; Miremadi, S. G ; Zarandi, H. R ; Sharif University of Technology
2005
Abstract
This paper presents an experimental evaluation of transient effects on SRAM-based FPGAs. A total of 9000 transient faults were injected into the target FPGA using Power Supply Disturbances (PSD). The results show that nearly 60 percent of faults cause system failures and about 58 percent of the faults lead to corruption of the configuration data of the FPGA chip. © 2005 IEEE
A design procedure for optimizing the LLC resonant converter as a wide output range voltage source
, Article IEEE Transactions on Power Electronics ; Volume 27, Issue 8 , 2012 , Pages 3749-3763 ; 08858993 (ISSN) ; Rashidian, B ; Zolghadri, M. R ; Alavi, S. M. H ; Sharif University of Technology
2012
Abstract
LLC resonant converter is one of the most suitable circuit topologies that have been introduced for designing constant output voltage switched-mode power supplies. In this paper, a design procedure is introduced for using this converter as a wide output range voltage source. Unlike constant output voltage applications which need small converter inductance ratio and narrow switching frequency variations, for wide output range applications, large values of these parameters are needed simultaneously and should be optimized. Instead of minimizing the components stresses, leading to a great value of the inductance ratio, proper choice of the converter parameters resulting in a smaller inductance...
A predictive voltage controller for stabilizing single fuel cell convertor
, Article 4th IEEE Electrical Power and Energy Conference: "Sustainable Energy for an Intelligent Grid", EPEC 2010, Halifax, NS, 25 August 2010 through 27 August 2010 ; 2010 ; 9781424481880 (ISBN) ; Nasirian, V. R ; Roshandel, R ; Zolghadri, M. R ; Fathi, A. H ; Noroozi, N ; Sharif University of Technology
2010
Abstract
Serious and challengeable role in markets of low power supplies for cellular phones and other small portable devices is expected for single fuel cell in future. Single fuel cell voltage level is extremely low in comparison with its output current. According to the extremely low level of the voltage, a suitable dc/dc boost converter must be used for increasing the voltage. In this paper, a model for a single fuel cell is presented and the effect of external load variation and changing of reactant pressure on cell performance is investigated. Moreover, a predictive voltage controller for boost convertor of PEM fuel cell is presented, simulated and validated using MATLAB/Simulink. The results...
A sectionalizing method in power system restoration based on wide area measurement systems
, Article EPEC 2010 - IEEE Electrical Power and Energy Conference: "Sustainable Energy for an Intelligent Grid", 25 August 2010 through 27 August 2010 ; August , 2010 ; 9781424481880 (ISBN) ; Salehi Dobakhshari, A ; Azizi, S ; Ranjbar, A. M ; Nouri Zadeh, S ; Sharif University of Technology
Abstract
This paper presents a novel sectionalizing method for the build-up strategy in power system restoration. Power system restoration is the procedure of restoring power system elements after a partial or a complete blackout. Because of its economic and political importance, different strategies have been developed for power system restoration. One of the most practical and economical is the build-up strategy that includes the process of restoring separated parts (islands) in the power system and interconnecting them afterwards. This paper intends to develop a systematic algorithm for sectionalizing a power system considering various constraints such as black-start capability of generators,...
A Fast vacuum arc detection method based on the neural network data fusion algorithm for the high-voltage dc power supply of vacuum tubes
, Article IEEE Transactions on Plasma Science ; 2020 ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
Vacuum arc is one of the most important failure factors of the vacuum tubes. The amount of delivered energy from the high-voltage dc power supply to the vacuum tube is an important issue during the vacuum arc in the tube. Vacuum arc acts as a short-circuit fault (SCF) at the power supply output. The majority of converters use a single current sensor to measure only the converter output current for detecting the SCF. However, the sensor may provide unreliable data because of the noise effect. Application of a low-pass filter reduces the noise effect. Regarding the delay of the low-pass filter, the interval of arc detection increases and more energy is delivered to the tube. In this article, a...
A new low voltage, high PSRR, CMOS bandgap voltage reference
, Article 2008 IEEE International SOC Conference, SOCC, Newport Beach, CA, 17 September 2008 through 20 September 2008 ; 2008 , Pages 345-348 ; 9781424425969 (ISBN) ; Atarodi, M ; Chahardori, M ; Sharif University of Technology
2008
Abstract
A new low voltage bandgap reference (BGR) in CMOS technology, with high power supply rejection ratio (PSRR) is presented. The proposed circuit uses a regulated current mode structure and some feedback loops to reach a low voltage, low power and high PSRR voltage reference. The circuit was designed and simulated in 0.18um CMOS technology, with a power supply of 1.4 volt. The results show PSRR is 65dB at 1MHz and the output voltage variation versus temperature (-40 to 140) is less than 0.1%. This circuit shows robustness against process variation. ©2008 IEEE
Research on the effect of transients of high-voltage power supplies on the lifetime of high-power vacuum tubes: A microscopic assessment
, Article IEEE Transactions on Plasma Science ; Volume 50, Issue 11 , 2022 , Pages 4700-4708 ; 00933813 (ISSN) ; Ziaoddini, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
Electron guns are used as the electron sources in high-power electron tubes. The generated electron beam in electric guns passes through an aperture at the center of the anode. Since the electron beam has considerable kinetic energy, any collision between the electron beam and the anode aperture edge damages the electron gun. Therefore, electron guns are designed to meet the compatibility between the diameters of the electron beam and the anode aperture. However, this compatibility is disrupted during the transient time interval of the gun's power supply. In this article, the cause of failure of the electron gun of high-power electron tubes is investigated for the transient interval of the...
Optimizing the LLC-LC resonant converter topology for wide-output-voltage and wide-output-load applications
, Article IEEE Transactions on Power Electronics ; Volume 26, Issue 11 , 2011 , Pages 3192-3204 ; 08858993 (ISSN) ; Zolghadri, M. R ; Rashidian, B ; Alavi, S. M. H ; Sharif University of Technology
2011
Abstract
LLC-LC resonant converter is a suitable circuit topology to design switched-mode power supplies for wide-output-voltage and wide-output-load applications. In this paper, a design procedure is introduced to optimize this converter. Unlike soft switching techniques for pulse width modulated converters, which usually apply an active auxiliary circuit to reduce switching losses and EMI, in the proposed converter, not only such circuits are not used, but also all of the parasitic elements are merged to the converters main components. Zero-voltage switching (ZVS) operation is realized for all power devices under all operating conditions. Thus, this converter is a suitable choice for...
A simplified droop method implementation in parallel UPS inverters with Proportional-Resonant controller
, Article Iranian Journal of Science and Technology, Transaction B: Engineering ; Volume 33, Issue 2 , 2009 , Pages 163-178 ; 10286284 (ISSN) ; Mokhtari, H ; Sharif University of Technology
2009
Abstract
In this paper, a simpler implementation of the well-known droop method for the control of parallel Uninterruptible Power Supply (UPS) systems is presented. In this method, in the power-sharing control scheme, the output current is calculated by software without the need for a current sensor, resulting in a simpler and cheaper structure. By doing so, the number of feedback sensors is reduced from three to two. The paralleling strategy uses the droop method in which the control strategy is based on the drop in the inverter output frequency and amplitude. The application of Proportional-Resonant (PR) controllers is also extended to parallel inverter and its superior performance over the...
Control of Quasi-Resonant Converters Using Model Predictive Control
, M.Sc. Thesis Sharif University of Technology ; Tahami, Farzad (Supervisor)
Abstract
DC-DC switching convertors are power electronic circuits that have various applications nowadays. Quasi-resonant convertors are a kind of these convertors that are of great interest due to their simple structure and soft switching. The goal of controlling these convertors is to achieve constant output voltage while varying the input voltage and the load by choosing a proper switching frequency. Classic controllers show drawbacks in the case of high input voltage and load tolerance, and this nonlinear behavior of the systems results in some practical challenges. In this thesis, nonlinear predictive controller for quasi-resonant Buck convertors is designed. Having designed the linear...
Energy-Aware Service Job Scheduling in Data Center with Distributed UPS and Renewable Energy
, M.Sc. Thesis Sharif University of Technology ; 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...
Applying of Data Fusion Method for Improving the Protection System of the High Voltage DC Power Supply
, M.Sc. Thesis Sharif University of Technology ; Kaboli, Shahriyar (Supervisor)
Abstract
Short-circuit fault detection is mandatory in a high voltage DC power supply to prevent fatal damage. The majority of converters employ a single sensor to detect the short-circuit fault. This attribute increases the interference vulnerability of the fault detection system in the presence of noise. Therefore, miss detections and false alarms are possible to occur. Miss detections and false alarms are harmful catastrophes in most applications. A commonly used method to suppress the noise impacts is using a low-bandwidth low-pass filter. However, the use of the low-bandwidth low-pass filter reduces the speed of fault detection due to the filter delay. This paper proposes a fast fault detection...
Analysis and Optimal Design of High-Voltage High-Frequency Transformer with Parasitic Elements Consideration for Microwave Power Module
, Ph.D. Dissertation Sharif University of Technology ; Kaboli, Shahriyar (Supervisor)
Abstract
Applications of high voltage power supplies is increasing. Microwave power module is one of the applications. In microwave power module, the dimensions of the power supply are very important. On the other hand, the parasitic elements of the transformer of a high voltage power supply are significant because of high insulation distances and transformer high turn ratio. These elements including stray capacitance and leakage inductance change the converter behavior. In this thesis, a method for dimensional efficient design of high voltage power supply used in microwave power module is presented considering and analyzing the transformer parasitic elements. Beforehand, at first, the transformer...