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power-supplies
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Total 139 records
Optimization of biomass waste gasification combined heat and power system
, 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) ; Marzi, H ; Abolghasem, H ; Sharif University of Technology
2010
Abstract
The objective of the research done in this paper was to determine cost of the power and heat system with pressurized fluidized bed gasifier using exergoexonomic appraisal techniques. Exergetic efficiency maximization was approached with use of multi-objective evolutionary optimization methods which were designed such that the costs were minimized in line with the exergoeconomic plans. The results of this method were also compared to methods that employ iterative techniques. Results showed an almost 12.28% improvement in exergetic efficient that the system could reach through utilization of the multi-objective evolutionary algorithm
A fast and series-stacked IGBT switch with balanced voltage sharing for pulsed power applications
, Article IEEE Transactions on Plasma Science ; Volume 44, Issue 10 , 2016 , Pages 2013-2021 ; 00933813 (ISSN) ; Mohsenzade, S ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Abstract
The series configuration of fast semiconductor switches seems to be the key component in the high-voltage and fast rising time pulse generation. In this approach, two important issues must be considered. The first is to provide a safe operating condition for the switches in transient intervals. The second is to design a gate drive system with the capability of driving a large number of discrete devices simultaneously. The aim of this paper is to obviate these two requirements. First, different factors affecting the unbalanced voltage sharing between the series switches are discussed. In this investigation, the switch-to-ground parasitic capacitance effect has been recognized as the major...
Analysis of a 6-DOF redundantly actuated 4-legged parallel mechanism
, Article Nonlinear Dynamics ; Volume 58, Issue 4 , 2009 , Pages 611-622 ; 0924090X (ISSN) ; Vossoughi, G. R ; Sharif University of Technology
Abstract
In this paper, we propose a new 4-legged 6-DOF redundantly actuated UPS parallel mechanism. Kinematics, singularity and dynamics analyses of the proposed mechanism are addressed. Inverse kinematics has a closed-form solution, whereas the forward kinematics has a semi-closed form solution. Also, the Jacobian matrix has been determined using the concept of reciprocal screws. Using the principle of virtual work and minimum norm method, a general formulation for the inverse dynamics of redundantly actuated parallel manipulator is presented. Moreover, the proposed redundant mechanism has been compared with a similar but nonredundant mechanism in three aspects: reachable points, and actuation...
A high power high voltage short pulse width pulse generator using direct drive method in application of modulating-cathode tubes drive
, Article IEEE International Symposium on Industrial Electronics, 5 July 2009 through 8 July 2009 ; 2009 , Pages 2097-2102 ; 9781424443499 (ISBN) ; Sadriyeh, S. M. R ; Mohammadi, A ; Maghsoudlou, B ; Mokhtari, H ; Alizadeh, H. R ; Shams Mousavi, S. M ; Sharif University of Technology
Abstract
The power supply of microwave tubes has high voltage and the possibility of produce high power pulse, which called in modulator. In this work, the results of design, construction and characterization of a direct drive pulse modulator for driving high power short pulse-width magnetron are reported. The sub-assemblies of modulator are; a primary high voltage supply, a switch bank with drivers and snubber circuits, a filament circuit, a digital control circuit with sensors and finally a pulse transformer. This paper is concerned with introduction and presentation of experimental evaluation of a new drive method for high power high voltage modulating-cathode microwave tubes. ©2009 IEEE
A Multi-Output high voltage dc power supply with fast regenerative rectifier
, Article 26th Iranian Conference on Electrical Engineering, ICEE 2018, 8 May 2018 through 10 May 2018 ; 2018 , Pages 1264-1268 ; 9781538649169 (ISBN) ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
A major problem in a multiple output converter structure is the different power flow via its various outputs. This problem leads to unwanted input DC-link voltage. This paper studies full bridge based DC-DC converters with multiple outputs. The effect of power flow variation is studied and a regenerative converter topology which controls the DC-link voltage by space voltage vector modulation technique is proposed. The proposed converter has a fast response to control the DC-link voltage in an acceptable band. Simulation and experimental results are presented to verify the analytical studies. © 2018 IEEE
An investigation on the quality of output voltage waveform in a nanosecond pulse generator using reverse recovery diodes
, Article 9th Annual International Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2018 ; Volume 2018-January , 19 April , 2018 , Pages 516-521 ; 9781538646977 (ISBN) ; Kaboli, S ; Eskandary, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Nanosecond pulsed-power generators have many applications in industries. As the rise time and fall time of conventional semiconductor switches are usually more than a few nanoseconds, it is necessary to employ special switches or new pulse generating methods to achieve nanosecond pulses. A common method for producing narrow pulse voltage waveforms is using the reverse recovery process of diodes. In this method, a super fast recovery diode is used as an opening switch in an inductor current path. A drift step recovery diode can form a rapid cut-off current front; Hence this method can be an effective solution to generate narrow pulses. This paper describes an investigation about the effect of...
Nonuniform line generator for high-power RF applications
, Article IEEE Transactions on Plasma Science ; Volume 46, Issue 1 , 2018 , Pages 64-71 ; 00933813 (ISSN) ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Line generators were attractive structures for high-power radio frequency (RF) pulse generation for two decades. Due to some disadvantages, there has been little attention to this type of generator for a relatively long time. In this paper, a nonuniform line generator is used which resolves some of the main shortcomings of conventional line generators. The considered generator can generate RF pulses at higher frequencies with considerably higher repetition rates. Furthermore, the implementation of nonuniform line generators is significantly easier than that of their conventional counterparts. Measurement results for three nonuniform line generators are presented. The possibility of...
Performance evaluation of custom power devices in process of motor bus transfer
, Article 2009 4th IEEE Conference on Industrial Electronics and Applications, ICIEA 2009, Xi'an, 25 May 2009 through 27 May 2009 ; 2009 , Pages 2279-2284 ; 9781424428007 (ISBN) ; Abedi, M ; Darabi, F ; Sharif University of Technology
2009
Abstract
Quality and continuity of electrical power to sensitive loads especially in power plants and industrial sectors is of great importance. For this reason, bus transfer is used. During the bus transfer interval, sensitive loads especially motors will be interrupted, and may encounter difficulties. So, it is used reactive power compensator and custom power devices to mitigate stress in motors and improve power quality indices. This paper presents the effect of reactive power compensator and custom power devices paralleling with motor in process of bus transfer which is done in two methods: EMTS and STS. Also, it is investigated dynamic performance of induction motor and spin-down curves in...
A high voltage variable inductor LCC resonant converter with high power factor over wide load range
, Article 10th International Power Electronics, Drive Systems and Technologies Conference, PEDSTC 2019, 12 February 2019 through 14 February 2019 ; 2019 , Pages 279-284 ; 9781538692547 (ISBN) ; Ayoubi, R ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
High voltage power supplies (HVPS) are widely used to supply vacuum tubes. Regarding to their high efficiency, resonant converters are a choice of HVPS structure. In this application, HVPS is faced with wide variation of the load power. On the other hand, output voltage regulation over wide load range is essential. However, there are several problems dealing with resonant converters such as output voltage regulation and low-efficient performance in a light load. In this paper, a control scheme for a series-parallel resonant converter is presented. This scheme regulates the output voltage of the converter over load variation range. A variable inductor placed as the series inductor in the...
Twin growth in RF window ceramic as a criterion for the response time of protection system in high power vacuum tubes
, Article 2019 International Vacuum Electronics Conference, IVEC 2019, 28 April 2019 through 1 May 2019 ; 2019 ; 9781538675342 (ISBN) ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
The ceramic fracture in output RF window is one of the most important failure factors in high power microwave sources. Fast protection systems are used to protect the source. The methods for determining the required protection response time are conservative and rough. In this paper, an investigation is presented about the twin growth in the ceramic of RF window in faulty condition. It is shown that the twin growth in ceramic can be a reliable figure of merit for the response time calculation of the microwave source protection system
Energy-Efficient permanent fault tolerance in hard real-time systems
, Article IEEE Transactions on Computers ; 2019 ; 00189340 (ISSN) ; Bakhshalipour, M ; Sadrosadati, M ; Sarbazi Azad, H ; Sharif University of Technology
IEEE Computer Society
2019
Abstract
Triple Modular Redundancy (TMR) is a historical and long-time-used approach for masking various kinds of faults. By employing redundancy and analyzing the results of three separate executions of the same program, TMR is able to attain excellent levels of reliability. While TMR provides a desirable level of reliability, it suffers from the high power consumption of the redundant hardware, a severe detriment to its broad adoption. The energy consumption of TMR can be mitigated if its operations are divided into two stages, and one stage is dropped in the absence of fault. Such an approach, which is evaluated in recent research, however, quickly fails in the presence of permanent faults, as we...
Energy-Efficient permanent fault tolerance in hard real-time systems
, Article IEEE Transactions on Computers ; 2019 ; 00189340 (ISSN) ; Bakhshalipour, M ; Sadrosadati, M ; Sarbazi Azad, H ; Sharif University of Technology
IEEE Computer Society
2019
Abstract
Triple Modular Redundancy (TMR) is a historical and long-time-used approach for masking various kinds of faults. By employing redundancy and analyzing the results of three separate executions of the same program, TMR is able to attain excellent levels of reliability. While TMR provides a desirable level of reliability, it suffers from the high power consumption of the redundant hardware, a severe detriment to its broad adoption. The energy consumption of TMR can be mitigated if its operations are divided into two stages, and one stage is dropped in the absence of fault. Such an approach, which is evaluated in recent research, however, quickly fails in the presence of permanent faults, as we...
Low power receiver with merged N-path LNA and mixer for MICS applications
, Article AEU - International Journal of Electronics and Communications ; Volume 117 , 2020 ; Safarian, A ; Sharif University of Technology
Elsevier GmbH
2020
Abstract
In this paper, a low power receiver for medical implant communication service (MICS) is presented. Low power design is vital in the MICS applications since the implanted chip has to work for a long time without the need to change its battery. As a result, a merged N-path low noise amplifier (LNA) and mixer block is proposed. In this structure, the LNA and down-conversion mixer share a transconductance to lower the overall power consumption. An N-path feedback is utilized around the shared transconductance not only to improve the LNA selectivity and relax the linearity requirements but also to downconvert the radio frequency (RF) component and create the intermediate frequency (IF) signal. In...
CHANCE: Capacitor charging management scheme in energy harvesting systems
, Article IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems ; 2020 ; Bahrami, M. R ; Ejlali, A ; Abam, M. A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
The energy efficiency of emerging nonvolatile processors equipped with FRAM-SRAM memory makes them a promising solution for energy harvesting systems. To enable correct functionality and forward progress with an unreliable power supply, the system must accumulate sufficient energy in the capacitor to execute tasks atomically, even in the worst case scenario. Due to the large gap between the average and worst case energy consumption of tasks, state of the art approaches like eM-map require a large capacitor to execute tasks on the SRAM. However, the size, cost, and charging time of the capacitor are major concerns in the energy harvesting systems. In this paper, we proposed CHANCE, a...
A study of pre-straining shape memory alloy (SMA)-based control elements subject to large-amplitude cyclic loads
, Article Ships and Offshore Structures ; 2020 ; Zabihollah, A ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
Dynamic environmental loads, such as winds and waves, make the stability of offshore structures at high risk, requiring reliable yet efficient control elements to ensure the stability of such structures under lateral loads. Among the variety of control elements that have been developed to enhance the stability of a structure, shape memory alloy (SMA)-based control elements are promising as they are low-cost, easy to embed into the main control element, and do not need an external power supply. However, cyclic loads may highly influence the performance and functionality of SMA-based elements. The present work investigates the effects of pre-straining SMA components in energy dissipation...
Transmission capability improvement using wide area monitoring and control
, Article 2008 IEEE Electrical Power and Energy Conference - Energy Innovation, Vancouver, BC, 6 October 2008 through 7 October 2008 ; January , 2008 ; 9781424428953 (ISBN) ; Ranjbar, A. M ; Nourizadeh, S ; Sharif University of Technology
2008
Abstract
Operation of transmission lines are usually limited by stability limits rather than thermal capacity limits. Thermal limit of transmission lines is a physical limitation of their components and not related with the overall power system characteristics, but stability limits are strictly related with power system characteristics. This paper presents an approach for increasing stability limits using PSS. © 2008 IEEE
Power system stabilizer tuning using wide area control signals
, Article 2008 IEEE Electrical Power and Energy Conference - Energy Innovation, Vancouver, BC, 6 October 2008 through 7 October 2008 ; 2008 ; 9781424428953 (ISBN) ; Ranjbar, A. M ; Nourizadeh, S ; Sharif University of Technology
2008
Abstract
Abstract- Benefits of PSS application for electromechanical oscillations damping is clarified. A major difficulty of PSS application is its tuning such that its damping characteristics do not fall into overcompensation facing continuously changing power systems. This paper presents an approach for wide area monitoring and control based PSS tuning. The presented approach originated from adaptive tuning based on real time power system state estimation. © 2008 IEEE
Multi objective power system restoration
, Article 2008 IEEE Electrical Power and Energy Conference - Energy Innovation, Vancouver, BC, 6 October 2008 through 7 October 2008 ; January , 2008 ; 9781424428953 (ISBN) ; Ranjbar, A. M ; Sharif University of Technology
2008
Abstract
This paper presents a stochastic model for optimal generating units' restoration planning. Restoration plans will be performed based on different objectives i.e. total system risk, total served energy in the period of restoration, and total restoration time. The proposed model is a multi objective stochastic program in which generating units' restoration plan is assumed to optimize different kinds of objective function. The proposed approach to the optimal restoration of generating units can be used by vertically integrated utilities as well as the ISOs in electricity markets. The approach coordinates the optimal start up of generating units within the restoration period. Physical...
Reliability worth assessment of an advanced centralized feeder automation scheme
, Article 2008 IEEE Electrical Power and Energy Conference - Energy Innovation, Vancouver, BC, 6 October 2008 through 7 October 2008 ; 2008 ; 9781424428953 (ISBN) ; Fotuhi Firuzabad, M ; Lehtonen, M ; Sharif University of Technology
2008
Abstract
Feeder Automation (FA) has been recognized by researchers and utilities as one of the attractive remedial measures to enhance service reliability in the electric power distribution systems. Until now, several kinds of FA schemes have been developed for automating of distribution feeders. They can be categorized into three main approaches: semiautomatic, distributed and centralized schemes. The challenge for the utilities, especially in today's competitive electricity market, is to identify and evaluate potential FA schemes and determine that appropriate for implementation. In this context, reliability cost/worth assessment plays an important role. This paper aims to propose a step by step...
Power flow control and solutions with dynamic flow controller
, Article 2008 IEEE Electrical Power and Energy Conference - Energy Innovation, Vancouver, BC, 6 October 2008 through 7 October 2008 ; 2008 ; 9781424428953 (ISBN) ; Sheykholeslami, A ; Nabavi Niaki, A ; Ghaffari, H ; Sharif University of Technology
2008
Abstract
this paper presents two new methods for power flow calculation of power systems in presence of Dynamic Flow Controller (DFC), which is a new member of FACTS controllers. In first method A new steady state model of DFC is introduced for the implementation of the device in the conventional Newton-Raphson power flow algorithm. The impact of DFC on power flow is accommodated by adding new entries and modifying some existing ones in the linearized Jacobian equations of the same system without DFC. The focus of second method is on the discrete nature of the DFC and including its effects on power flow. This method is based on Nabavi model for FACTS devices. A case study on a power system located in...