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power-electronics
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Improvement of Power Sharing In Microgrids Consist of Synchronous Generators and Converter Based Distributed Generation Units
, M.Sc. Thesis Sharif University of Technology ; Mokhtari, Hossein (Supervisor)
Abstract
This dissertation studies the operation of the power sharing system in a micro-grid (MG) which includes a synchronous generator and the converter based distributed generation (DG) units. Increasing advent of MGs and the huge penetration of DGs to the existing power systems require comprehensive studies on the interactions between synchronous generators and converter based DGs for the sharing of power during and after the occurrence of different disturbances such as load changing. Thus, this project discusses existing control methods which can be used to share the power between a synchronous generator and converter based DGs. Then, a new control strategy is proposed in order to enhance the...
Design and Implementation of FPGA Based Real Time Simulator for Power Electronic Converters
, M.Sc. Thesis Sharif University of Technology ; Zolghadri, Mohammad Reza (Supervisor)
Abstract
Real-time Simulator plays an important role in the test of power electronic converters. Using of this simulators and Hardware-in-the-loop tests, cost and time of experiments will redused, furthermore those experiments which are not operative on the real system, can be achived. However, the accuracy of the used model in simulation as well as fast and easy programming of these simulators is very important. Therefore in this thesis, design and implementation of real-time simulator for power electronic converters have been discussed that in addition to high accuracy of the simulation, implementation of the several tests will be easy. As regards the power electronic switch is the most important...
Study Dynamic Behavior of Fuel Cell Distributed Generation
, M.Sc. Thesis Sharif University of Technology ; Abbaspour Tehrani Fard, Ali (Supervisor)
Abstract
The necessity of electrical energy, high cost of big power plants and high voltage transmission lines and also progressing of restructuring science has lead to the increasing of tendency to use the distributed generation in electrical industry. Among of different types of distributed generations, fuel cell power plants because of many advantages such as high efficiency, low emission, modular structure and ect., have a high potential to be used in power systems. The fuel cells produce electrical energy by chemical reactions. Due to the necessity of having the knowledge related to the chemical reaction which are effective on fuel cell, to study the fuel cell performance, this type of...
Design of DC-DC Buck Converter Based on Reliability Considerations
, M.Sc. Thesis Sharif University of Technology ; Kaboli, Shahriyar (Supervisor)
Abstract
Nowadays power electronic devices have a wide usage in the industries for power conditioning. As a point of view, reliability is one of the most important figure of merits that should be considered to have long life time and also have more probability to do exactly the proposed mission. One of the widely used converter topologies is DC-DC step down converter which is used in different applications such as battery charger and voltage regulator. In this project, a step down DC-DC converter with Buck topology is designed with reliability consideration. Failure rate of power components are predicted based on MIL-HDBK-217. In addition, failure rate of auxiliary components of power devices are...
Converter Design for Hybrid Thermoelectricity and Solar Energy Harvesting for Wearable Sensors
, M.Sc. Thesis Sharif University of Technology ; Zolghadri, Mohammad Reza (Supervisor) ; Fakharzadeh Jahromi, Mohammad (Co-Supervisor)
Abstract
Power harvesters are used to generate energy for electronic devices. These electrical energy generators consist of three main parts: energy source, power electronic converter and energy storage. In order to minimize some of the weaknesses of these devices, including low power density and low reliability, the hybrid power harvesting method can be utilized. In this thesis, we design and build a hybrid energy harvester considering the advantages of simultaneous usage of solar and thermal energies for a wearable sensor, focusing on "efficiency enhancement" and "availability improvement". In the designed device, both solar and thermal energy harvesting units operate independently. In the solar...
Design and Implementation of High Efficient Power Converter for Small PM Synchronous Wind Generator
, M.Sc. Thesis Sharif University of Technology ; Tahami, Farzad (Supervisor)
Abstract
The global wind energy capacity has been increased rapidly in the past few years and became the fastest developing renewable energy technology. Small Permanent Magnet Synchronous Generators (PMSG’s) are widely used in low power wind turbines because they don’t need a gearbox and complicated control systems. In order to inject the electrical power generated by PMSG to the grid, an AC-DC-AC power electronic converter is required. A novel low cost efficient AC-DC converter is proposed to obtain the maximum power per ampere of PMSG. The new structure for the rectifier stage of the AC/AC converter is based on a DCM operated SEPIC converter and can convert the variable voltage and frequency of...
MFLP: a low power encoding for on chip networks
, Article Design Automation for Embedded Systems ; Volume 20, Issue 3 , 2016 , Pages 191-210 ; 09295585 (ISSN) ; Taassori, M ; Uysal, S ; Sharif University of Technology
Springer New York LLC
2016
Abstract
Network on chip (NoC) has been proposed as an appropriate solution for today’s on-chip communication challenges. Power dissipation has become a key factor in the NoCs because of their shrinking sizes. In this paper, we propose a new encoding approach aimed at power reduction by decreasing the number of switching activities on the buses. This approach assigns the symbols to data word in such a way that the more frequent words are sent by less power consumption. This algorithm dedicates the symbols with less ones to high probability data and uses transition signaling to transmit data. The proposed method, unlike the existing low power encoding, does not rely on spatial redundancy and keeps the...
A lightweight defense approach to mitigate version number and rank attacks in low-power and lossy networks
, Article Wireless Personal Communications ; Volume 99, Issue 2 , March , 2018 , Pages 1035-1059 ; 09296212 (ISSN) ; Movaghar, A ; Hosseinzadeh, M ; Sharif University of Technology
Springer New York LLC
2018
Abstract
The Internet of Things (IoT) presents a new paradigm of the future internet that intends to provide interactive communication between various processing object via heterogeneous networks. The routing protocol in the IoT environment is Routing Protocol for Low-Power and Lossy Networks (RPL). The current RPL specification defines primary security modes; therefore it is vulnerable to topological attacks. In this paper the RPL routing mechanism, its topological vulnerabilities and two important topological attacks namely version number attack and rank spoofing attack are analyzed. To counter the mentioned attacks, a lightweight Identity Based Offline–Online Signature based scheme is proposed....
A lightweight signcryption scheme for defense against fragment duplication attack in the 6LoWPAN networks
, Article Peer-to-Peer Networking and Applications ; 2018 , Pages 1-18 ; 19366442 (ISSN) ; Movaghar, A ; Hosseinzadeh, M ; Sharif University of Technology
Springer New York LLC
2018
Abstract
The Internet of Things (IoT) presents a new paradigm of the future Internet that intends to provide interactive communication between various processing objects via heterogeneous networks. The IPv6 over Low power Wireless Personal Area Networks (6LoWPAN) is an IPv6 adaptation sub-layer and provides the requirements of IP connectivity between resource-constrained devices in lossy, low power networks. Since the size of a packet in the IPv6 is larger than the size of a frame in the IEEE 802.15.4, the 6LoWPAN adaptation layer performs packet fragmentation. In this paper, first, the 6LoWPAN fragmentation mechanism in terms of security issues is analyzed and then, fragment duplication attack which...
A DC power system stabilizer based on passivity-oriented DC bus impedance shaping
, Article Scientia Iranica ; Volume 29, Issue 4 , 2022 , Pages 2029-2039 ; 10263098 (ISSN) ; Mokhtari, H ; Sharif University of Technology
Sharif University of Technology
2022
Abstract
High penetration of Power Electronic (PE) converters in DC power grids causes new stability challenges due to dynamic interactions among the subsystems of a network. Such dynamic interactions can be avoided by the impedance coordination among the subsystems through the modification of control loops or passive elements inside a grid. Impedance coordination is a very complex and time-consuming task with no adaptations to dynamic changes in a power grid. The current study delved into the concepts of dynamic interaction and passivity and they were combined to provide an online stability measure concerning the DC bus impedance characteristics. In this regard, a novel DC Power System Stabilizer...
Integrated photonic neural network based on silicon metalines
, Article Optics Express ; Volume 28, Issue 24 , 2020 , Pages 36668-36684 ; Marzban, M. R ; Khavasi, A ; Sharif University of Technology
OSA - The Optical Society
2020
Abstract
An integrated photonic neural network is proposed based on on-chip cascaded one-dimensional (1D) metasurfaces. High-contrast transmitarray metasurfaces, termed as metalines in this paper, are defined sequentially in the silicon-on-insulator substrate with a distance much larger than the operation wavelength. Matrix-vector multiplications can be accomplished in parallel and with low energy consumption due to intrinsic parallelism and low-loss of silicon metalines. The proposed on-chip whole-passive fully-optical meta-neural-network is very compact and works at the speed of light, with very low energy consumption. Various complex functions that are performed by digital neural networks can be...
Optimal distributed static series compensator placement for enhancing power system loadability and reliability
, Article IET Generation, Transmission and Distribution ; Volume 9, Issue 11 , 2015 , Pages 1043-1050 ; 17518687 (ISSN) ; Fotuhi Firuzabad, M ; Aminifar, F ; Safdarian, A ; Lehtonen, M ; Sharif University of Technology
Institution of Engineering and Technology
2015
Abstract
Distributed static series compensator (DSSC) is a member of the family of distributed flexible AC transmission system devices that can be attached directly to conductors of transmission lines. DSSCs are able to compensate for and adjust the line reactance; thus, they could be widely used in stability-limited transmission systems. Owing to economic matters, the optimal placement of DSSCs is of a great interest from practical viewpoints. This study presents an approach to find the optimal locations of DSSCs to enhance the system loadability and reliability using the DC load flow model. The optimisation problem is solved using the mixed-integer linear programming. A compromise between improving...
Low energy yet reliable data communication scheme for network-on-chip
, Article IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems ; Volume 34, Issue 12 , 2015 , Pages 1892-1904 ; 02780070 (ISSN) ; Palesi, M ; Eskandari, S ; Hessabi, S ; Afzali-Kusha, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
In this paper, a low energy yet reliable communication scheme for network-on-chip is suggested. To reduce the communication energy consumption, we invoke low-swing signals for transmitting data, as well as data encoding techniques, for minimizing both self and coupling switching capacitance activity factors. To maintain the communication reliability of communication at low-voltage swing, an error control coding (ECC) technique is exploited. The decision about end-To-end or hop-To-hop ECC schemes and the proper number of detectable errors are determined through high-level mathematical analysis on the energy and reliability characteristics of the techniques. Based on the analysis, the extended...
An efficient DVS scheme for on-chip networks using reconfigurable Virtual Channel allocators
, Article Proceedings of the International Symposium on Low Power Electronics and Design, 22 July 2015 through 24 July 2015 ; Volume 2015-September , July , 2015 , Pages 249-254 ; 15334678 (ISSN) ; 9781467380096 (ISBN) ; Mirhosseini, A ; Aghilinasab, H ; Sarbazi Azad, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Network-on-Chip (NoC) is a key element in the total power consumption of a chip multiprocessor. Dynamic Voltage Scaling is a promising method for power saving in NoCs since it contributes to reduction in both static and dynamic power consumptions. In this paper, we propose a novel scheme to reduce on-chip network power consumption when the number of Virtual Channels (VCs) with active allocation requests per cycle is less than the number of total VCs. In our method, we introduce a reconfigurable arbitration logic which can be configured to have multiple latencies and hence, multiple slack times. The increased slack times are then used to reduce the supply voltage of the routers in order to...
DRVS: Power-efficient reliability management through Dynamic Redundancy and Voltage Scaling under variations
, Article 20th IEEE/ACM International Symposium on Low Power Electronics and Design, ISLPED 2015, 22 July 2015 through 24 July 2015 ; Volume 2015 , September , 2015 , Pages 225-230 ; 15334678 (ISSN) ; 9781467380096 (ISBN) ; Tavana, M. K ; Rehman, S ; Kriebel, F ; Shafique, M ; Ejlali, A ; Henkel, J ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Many-core processors facilitate coarse-grained reliability by exploiting available cores for redundant multithreading. However, ensuring high reliability with reduced power consumption necessitates joint considerations of variations in vulnerability, performance and power properties of software as well as the underlying hardware. In this paper, we propose a power-efficient reliability management system for many-core processors. It exploits various basic redundancy techniques (like, dual and triple modular redundancy) operating in different voltage-frequency levels, each offering distinct reliability, performance and power properties. Our system performs Dynamic Redundancy and Voltage Scaling...
Performance improvement of steady-state and transient operation of offshore wind farm HVDC power transmission
, Article 2015 IEEE 16th Workshop on Control and Modeling for Power Electronics, COMPEL 2015, 12 July 2015 through 15 July 2015 ; July , 2015 , Page(s): 1 - 7 ; 9781467368476 (ISBN) ; Ebrahimi, S ; Parniani, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Wind power generation is increasing fast as a clean renewable energy resource. Offshore wind farms are popular due to advantages such as higher and smoother wind speeds, less farm site limitations, etc. High capacitive currents and need to expensive compensations, make use of high-voltage-direct-current (HVDC) power transmission indispensable for longdistance wind farm power generations. Steady-state and transient performance improvements of HVDC systems have always been an interesting industrial and academic research area. In this paper, a novel control method is proposed to improve the steady-state operation of HVDC system. Moreover, a new fault detection scheme is proposed to improve the...
Simulation and investigation of a back-triggered 6H-SiC high power photoconductive switch
, Article 6th Annual International Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2015, 3 February 2015 through 4 February 2015 ; February , 2015 , Pages 253-256 ; 9781479976539 (ISBN) ; Faez, R ; Amiri, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
This paper has investigated the performance of a linear, 6H-SiC high power photoconductive semiconductor switch. A three-dimensional device modeling with SILVACO ATLAS tools was used to model the optically initiated 6H-SiC switch. The 6H-SiC PCSS device is designed in a rear-illuminated, radial switch structure. The material properties of vanadium compensated 6H-SiC PSCC have been analyzed for breakdown, photocurrent profile such as rise and fall time in terms of their applications as a photoconductive switch at high bias conditions. This structure and also new type of illumination extends the blocking voltage by reducing the peak electric field near electrodes. In this presentation the...
An isolated three-phase three-switch buck rectifier with inrush current limiting
, Article 6th Annual International Power Electronics, Drive Systems, and Technologies Conference ; 2015 , Pages 480-485 ; 9781479976539 (ISBN) ; Zolghadri, M. R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
In this paper a single stage structure is proposed for realizing a three-phase unity power factor rectifier. This topology utilizes a forward/flyback transformer to allow the high-frequency isolation. The principle of the operation and the applied control concept is discussed. Space vector modulation is used in order to achieve unity power factor and to have the output voltage be regulated. Furthermore, the system transient is analyzed during turn-on and a novel method is applied to the control system in order to limit inrush current during startup. The proper operation of the soft-start method is confirmed by numerical simulation of a 6KW, 380V/48Vdc. The stability of the closed-loop as...
A new t-type direct AC/AC converter
, Article 6th Annual International Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2015, 3 February 2015 through 4 February 2015 ; February , 2015 , Pages 247-252 ; 9781479976539 (ISBN) ; Zolghadri, M. R ; Noroozi, N ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
In this paper a novel T type scheme for 1-phase direct ac/ac converters is proposed. In this topology, frequency changing takes place directly (without common DC voltage bus) through three converters that are connected in a T structure. Unity power factor and precise output voltage regulation is achieved through appropriate control of these three converters. H-bridge converters are implemented, as the basic unit, in each branches of T to make the proposed converter. The converter is controlled such that the average active power of each H-bridges remains zero. So capacitors are implemented in DC links of H-bridges. In comparison to conventional back-to-back converters, life time of each...
Fast detection of open-switch fault in cascaded H-Bridge multilevel converter
, Article 6th Annual International Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2015, 3 February 2015 through 4 February 2015 ; February , 2015 , Pages 538-543 ; 9781479976539 (ISBN) ; Zolghadri, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Cascaded H-Bridge converter has recently been utilized in different high-power applications due to its modular and simple structure. In order to have a balanced operation after a fault occurrence in this converter, it is necessary to detect the switch fault and its location. In this paper, a fast power switch fault detection method is presented to identify the fault and its location. Only one voltage measurement per phase is required by this method, and the fault detection is faster compared to the existing methods. Moreover, it is easy for implementation on an FPGA device, due to the use of simple math, relational and state machine blocks. The proposed method is verified by computer...