Search for: power-supplies
Total 132 records
M.Sc. Thesis Sharif University of Technology ; Kaboli, Shahryar
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...
Improving the Direct Switching Method for High Voltage Applications to Improve the Load Voltage Waveform, Ph.D. Dissertation Sharif University of Technology ; Kaboli, Shahriyar
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...
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 ; Kaboli, Shahriar
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...
A novel LQR based optimal tuning method for IMP-based linear controllers of power electronics/power systems, Article Proceedings of the IEEE Conference on Decision and Control, 12 December 2011 through 15 December 2011 ; 2011 , Pages 7711-7716 ; 01912216 (ISSN) ; 9781612848006 (ISBN) ; Edrington, C. S ; Mokhtari, H ; Sharif University of Technology
This paper presents a new method for tuning linear controllers such as Proportional-Integrating (PI) and Proportional-Resonant (PR) structures which are frequently used in different power electronic and power system applications. Those controllers are placed within a general structure offered by the Internal Model Principle (IMP) of control theory. In this paper, the first perspective uses the well-known concept of Linear Quadratic Regulator (LQR) to address the problem as a regulation problem. Matrix Q of the LQR design is then finely adjusted in order to assure desired transient response for the system. The second perspective is based on redefining the LQR problem in order to make it...
Article IEEE Transactions on Industrial Electronics ; Volume 58, Issue 5 , 2011 , Pages 1746-1756 ; 02780046 (ISSN) ; Rashidian, B ; Zolghadri, M. R ; Alavi, S. M. H ; Sharif University of Technology
LLC resonant converter with significant resonant inductance is proposed for designing an adjustable wide-range regulated voltage source. Large resonant inductance increases output voltage adjustment range and conversion efficiency, particularly at light loads. Soft switching is achieved for all power devices under all operating conditions by choosing the dead time and maximum switching frequency properly and operating in the converter's inductive region. Using a power-factor-correction (PFC) converter reduces the resonant converter's output voltage dependence to the variations of the main ac input voltage. Thus, the compensation of the load variations and the wide-range adjustment of the...
Article EPEC 2010 - IEEE Electrical Power and Energy Conference: "Sustainable Energy for an Intelligent Grid", 25 August 2010 through 27 August 2010, Halifax, NS ; 2010 ; 9781424481880 (ISBN) ; Sadeghzadeh, S. M ; Fathi, A. H ; Nasiri, M ; Sharif University of Technology
Proton Exchange Membrane (PEM) Fuel Cells are attracting most of the electricity consumers because of high efficiency, zero carbon emissions and high reliability. There are many parameters influencing on this power source's operation. A model of PEM fuel cell will be presented and the sensitivity of the fuel cell's parameters will be analyzed. Multi Parameters Sensitivity Analysis is used next to examine the relative importance of the influential parameters on the PEM fuel cell operation
Article Microelectronics Journal ; Volume 41, Issue 8 , August , 2010 , Pages 506-522 ; 00262692 (ISSN) ; Tahoori, M. B ; Sharif University of Technology
Soft errors due to cosmic radiations are the main reliability threat during lifetime operation of digital systems. Fast and accurate estimation of soft error rate (SER) is essential in obtaining the reliability parameters of a digital system in order to balance reliability, performance, and cost of the system. Previous techniques for SER estimation are mainly based on fault injection and random simulations. In this paper, we present an analytical SER modeling technique for ASIC designs that can significantly reduce SER estimation time while achieving very high accuracy. This technique can be used for both combinational and sequential circuits. We also present an approach to obtain...
Article 2nd International Conference on Computer and Network Technology, ICCNT 2010, 232010 through 25 April 2010 ; April , 2010 , Pages 71-75 ; 9780769540429 (ISBN) ; Attarzadeh, H ; Sharifkhani, M ; Sharif University of Technology
Advance Encryption Standard (AES), has received significant interest over the past decade due to its performance and security level. In this paper, we propose a compact 8-bit AES crypto-processor for area constrained and low power applications where both encryption and decryption is needed. The cycle count of the design is the least among previously reported 8-bit AES architectures and the throughput is 203 Mbps. The AES core consumes 5.6k gates in 0.18 μm standard-cell CMOS technology. The power consumption of the core is 49 μW/MHz at 128 MHz which is the minimum power reported thus far
Article 2009 IEEE Electrical Power and Energy Conference, EPEC 2009, 22 October 2009 through 23 October 2009 ; 2009 ; 9781424445080 (ISBN) ; Hoseinnia, S ; Roshandel, R ; Sharif University of Technology
Fuel Cell (FC) is one of the promising distributed generation resources which are based on renewable energies. Clean electricity generation, high efficiency and high energy density of the fuel cells make them attractive for lots of engineers. In this paper we discuss about the operational principles of fuel cell generally. Then, a circuit model of them will be introduced. Based on the model, we designed a novel DC/DC converter for supplying the fuel cell's load and simulated the design with using Matlab. The results say that its novel converter could conveniently supply the load and its needed power curve. ©2009 IEEE
On the effect of disorder on stray capacitance of transformer winding in high-voltage power supplies, Article IEEE Transactions on Industrial Electronics ; Volume 64, Issue 5 , 2017 , Pages 3608-3618 ; 02780046 (ISSN) ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2017
Stray capacitance of transformer winding is an important parasitic element influencing the behavior of the switching power converters, especially for high-voltage transformers. There are various methods for calculating the stray capacitance in transformers and inductors with ordered windings. However, an ordered winding is less likely with an increased number of turns and layers. In this paper, it is shown that a slight disorderliness in winding leads to a considerable difference between the value of winding stray capacitance of the former ordered winding and its slightly disordered scheme. Therefore, regular methods for calculating the stray capacitance have significant errors in a...
Article 26th Iranian Conference on Electrical Engineering, ICEE 2018, 8 May 2018 through 10 May 2018 ; 2018 , Pages 283-288 ; 9781538649169 (ISBN) ; Naghibi Nasab, J ; Elyasi, M ; Zarrabi, R ; Vosoghi, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2018
Electrospray technique is one of the commonly used methods for generating nanoparticles. In this method, the chemical solution which consists of a polymer and its solvent are injected into an electric field via a nozzle. At the end of this nozzle, due to electric forces, a certain part of this liquid is separated. Then, the separated part is divided into smaller particles and the solvent is evaporated and hence, the nanoparticles are acquired. Produced nanoparticales are collected in deionized water placed under the certain distant from nozzle. However, construction of this method is generally based on practical results. In this paper, modeling and performance evaluation of high voltage...
Article IET Generation, Transmission and Distribution ; Volume 13, Issue 20 , 2019 , Pages 4617-4629 ; 17518687 (ISSN) ; Niknam, T ; Fotuhi Firuzabad, M ; Sharif University of Technology
Institution of Engineering and Technology 2019
The integration of various energy supplying systems increases the energy efficiency and energy system reliability. Smart microgrids are an ideal area to use multi-carrier energy systems. In this context, this study presents a novel modelling framework for optimal day-ahead scheduling of a networked multi-carrier energy microgrid (NMCEMG) system. The NMCEMG system in this study is composed of heat, gas, and power supply networks. The presented framework has enhanced the multicarrier microgrid modelling against the previous works that modelled the multi-carrier microgrid as an energy hub due to difficulties in the energy flow analysis of heat and gas networks. The proposed framework optimises...
Article 27th Iranian Conference on Electrical Engineering, ICEE 2019, 30 April 2019 through 2 May 2019 ; 2019 , Pages 804-807 ; 9781728115085 (ISBN) ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2019
Power Distribution Unit (PDU) is a power supply unit that supplies various DC voltage levels for electric equipment. Reliability of PDU is very important in electrical systems. Buck converter is frequently used in PDU to provide the lower voltage levels than the source voltage level. The output capacitor of the buck converter is the main factor of failure. In this paper, we present a method to design a buck converter with almost no inductor current ripple. If the inductor current ripple is eliminated, the output capacitor can be removed from the converter. By removing the capacitor, the reliability and transient response of the converter can be improved considerably. The proposed method is...
Article 2019 International Vacuum Electronics Conference, IVEC 2019, 28 April 2019 through 1 May 2019 ; 2019 ; 9781538675342 (ISBN) ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2019
Microwave power modules are the result of integration of vacuum tubes and their respective power supplies. In these modules, volume and weight are very important factors because the modules are used in many portable applications. There are many parameters that they affect the volume and weight of the microwave power module. High voltage issues are one of these factors because the required voltages of vacuum tubes are high voltage. Thermal management relates to the module volume directly. In high-voltage high-frequency converters as power supplies of vacuum tubes, parasitic elements of the transformer are dominant. Tuning the transformer parameters leads to variation in the volume of the...
Article AEU - International Journal of Electronics and Communications ; Volume 99 , 2019 , Pages 361-368 ; 14348411 (ISSN) ; Moaiyeri, M. H ; Moghaddam, M ; Hessabi, S ; Sharif University of Technology
Elsevier GmbH 2019
This paper presents a single-ended low-power 7T SRAM cell in FinFET technology. This cell enhances read performance by isolating the storage node from the read path. Moreover, disconnecting the feedback path of the cross-coupled inverters during the write operation enhances WSNM by nearly 7.7X in comparison with the conventional 8T SRAM cell. By using only one bit-line, this cell reduces power consumption and PDP compared to the conventional 8T SRAM cell by 82% and 35%, respectively. © 2018 Elsevier GmbH
Article IEEE Transactions on Power Electronics ; Volume 35, Issue 8 , 2020 , Pages 7991-8001 ; Mohsenzade, S ; Hadizade, A ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2020
This article describes the development of an 18 kV, 30 kW power supply for a pulsed current load with the maximum current of 20 A and a di/dt equal to 100 A/μs. The achieved output ripple is less than 0.01%. In such a high level of precision, the most important issues are considerable difference between the instantaneous and average output powers, as well as insufficient reaction speed of the converter to the fast load change. Very low level of the voltage feedback and its sensitivity to the noise. The first issue necessitates a notable overdesign of the converter switches if the output voltage precision is dedicated to the converter. The second issue raises the problems relevant to...
Article 2008 IEEE International RF and Microwave Conference, RFM 2008, Kuala Lumpur, 2 December 2008 through 4 December 2008 ; April , 2008 , Pages 46-48 ; 9781424428663 (ISBN) ; Shishegar, A. A ; Sharif University of Technology
In this paper, a novel closed form expression is derived to find the Green's function of a horizontal electric current in a parallel-plate waveguide. It is achieved by expanding the Green's function into a series of Gaussian functions. This new method is called the Gaussian Green's function (GGF) method. The main advantage of the GGF method lies in its precision as well as rapid convergence. Numerical results confirm that the closed form expression yields less than 0.2% error compared to the numerical integration of the spectral integral. Furthermore, it is verified that this method can be in excellent agreement with the complex images (CI) method. © 2008 IEEE
Article 2007 IEEE Canada Electrical Power Conference, EPC 2007, Montreal, QC, 25 October 2007 through 26 October 2007 ; 2007 , Pages 256-260 ; 1424414458 (ISBN); 9781424414451 (ISBN) ; Bakshai, A ; Eren, S ; Sharif University of Technology
This paper presents several techniques for the processing of power system signals in a power system setup. The techniques exhibit a desirable performance against signal pollutions such as noise and distortions, signal unbalance (in three-phase applications), and Variations in the signal attributes (mainly its frequency). These features render them a promising set of options for modern power systems in which all or some of these undesired factors may be amplified depending on the case. Single-phase and three-phase applications are both examined and appropriate techniques are suggested for different scenarios. © 2007 IEEE
A voltage balancing method for series-connected igbts operating as a fault current limiter in high-voltage dc power supplies, Article IEEE Transactions on Industrial Electronics ; Volume 68, Issue 9 , 2021 , Pages 7895-7907 ; 02780046 (ISSN) ; Zarghani, M ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2021
This article proposes a high-voltage fault current limiter (HVFCL) for high-voltage dc power supplies (HVdcPSs) which limits the current of the power supply automatically in the short-circuit fault (SCF). The proposed HVFCL is based on the series-connected insulated gate bipolar transistors (IGBTs). The main achievements of this article are the balanced voltage sharing and a very low value of the short-circuit current near to the load nominal current for the series-connected IGBTs during the SCF. These achievements result in a longer maximum permissible short-circuit time. These achievements are obtained by a control strategy that puts the series-connected IGBTs in a specific operating point...
An IGBT-Based high-voltage crowbar for minimizing the fault current interruption time and injected fault energy during the vacuum arc fault in microwave tubes, Article IEEE Transactions on Plasma Science ; Volume 49, Issue 6 , 2021 , Pages 1941-1947 ; 00933813 (ISSN) ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2021
In conventional high-voltage power supplies used for driving the microwave tubes, the shunt crowbar, which generally consists of series-connected thyristors, protects the microwave tube against the vacuum arc fault. In the case of arc fault, the thyristor-based crowbar is closed as a parallel path and diverts the fault current through itself. It avoids serious damage to the microwave tube. However, thyristor switches usually have a limited rate of rise of ON-state current (di/dt), which necessitates placing a series inductor in the crowbar path. Thus, satisfying all protection limits of microwave tubes-including the injected fault energy and the fault current interruption time-is a...