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HTS transformer windings design using distributive ratios for minimization of short circuit forces
, Article Journal of Superconductivity and Novel Magnetism ; 2018 ; 15571939 (ISSN) ; Vakilian, M ; Hekmati, A ; Fardmanesh, M ; Sharif University of Technology
Springer New York LLC
2018
Abstract
High-temperature superconducting (HTS) transformers have a promising feature in reduction of total weight, total size, and the losses of large-scale distribution transformers. However, the lower leakage reactance of HTS transformers results in a higher short-circuit fault currents and electromagnetic forces. Therefore, optimization of short-circuit electromagnetic forces is one of the crucial aspects in the design of HTS transformers. In this paper, a novel analytical method is proposed for determination of optimum distributive ratios resulting in minimization of these forces for asymmetrical multi-segment windings of an HTS transformer. Employing these distributive ratios, radial and axial...
Low-Frequency model for hand-calculations in circuit design with TMDC-based transistors
, Article IEEE Transactions on Electron Devices ; Volume 66, Issue 11 , 2019 , Pages 5011-5018 ; 00189383 (ISSN) ; Safarian, A ; Pourfath, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
This article presents an applicable intuitive current-voltage model for long-channel transistors based on 2-D materials. This model carefully predicts the transistor behavior in the saturation and triode regions, which are important for analog and digital applications. Moreover, the effect of mobility degradation on the characteristics of the transistor is probed. As a case study, the developed model has been applied to a transistor with mono-layer MoS2 as the channel material. The excellent agreement with experimental data verifies the accuracy of the model. Finally, the introduced model has been utilized to design an amplifier, a differential pair, and a low-frequency common source mixer...
AM3D: An accurate crosstalk probability modeling to predict channel delay in 3D ICs
, Article Microelectronics Reliability ; Volume 102 , 2019 ; 00262714 (ISSN) ; Nikoofard, A ; Ershadi, G ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Migration from Two Dimensional Integrated Circuits (2D ICs) to Three Dimensional Integrated Circuits (3D ICs) reduces the delay due to the shorter wire length between sender and receiver. However, Through-Silicon-Vias (TSVs) that connect layers in the structure of 3D ICs can seriously increase the delay due to capacitance coupling between TSVs and lead to crosstalk fault. The severity of crosstalk faults depends on transitions appearing on TSVs that is called transition patterns. To propose an efficient crosstalk tackling mechanisms in 3D ICs, an accurate probability analytical model is required to predict the delay caused by TSVs (3D ICs) in the attendance of these transition patterns. In...
Multi-segment winding application for axial short circuit force reduction under tap changer operation in HTS transformers
, Article Journal of Superconductivity and Novel Magnetism ; Volume 32, Issue 10 , 2019 , Pages 3171-3182 ; 15571939 (ISSN) ; Vakilian, M ; Hekmati, A ; Fardmanesh, M ; Sharif University of Technology
Springer New York LLC
2019
Abstract
High-temperature superconducting (HTS) transformers have remarkable appealing advantages over conventional ones. But higher brittleness of HTS windings with respect to copper windings makes HTS transformers more vulnerable in short circuit and inrush current situations. During tap changer operation, appreciable asymmetry and non-uniform distribution of ampere-turn along the windings causes high axial component of short circuit forces and makes the situation more severe. In this paper, multi-segment winding method is employed for reduction of axial short circuit forces. An analytical method is presented for calculation of axial component of short circuit forces under tap changer operation....
Wide-Band RF front end for saw-less receivers employing active feedback and far out-of-band blocker rejection circuit
, Article IEEE Journal of Solid-State Circuits ; Volume 54, Issue 6 , 2019 , Pages 1528-1540 ; 00189200 (ISSN) ; Sharif Bakhtiar, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Elimination of the surface acoustic wave (SAW) filter from the input of a receiver can render it extremely vulnerable to various blockers and interferers. The presence of large out-of-band (OOB) blockers will result in the required linearity of the SAW-less receiver to be considerably higher than that of the conventional receivers with the input SAW filter. The ever-present undesirable signals that arise in the absence of the input SAW filter can be divided into two classes of far and near OOB blockers and interferers. Removal of these harmful signals requires two distinct approaches according to their nature. Two different methods for blocker and interferer rejection are introduced in this...
Wideband and narrowband circuit models for fano-shape guided-mode resonance
, Article IEEE Journal of Quantum Electronics ; Volume 55, Issue 3 , 2019 ; 00189197 (ISSN) ; Memarian, M ; Mehrany, K ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, we propose two different types of circuit models for Fano-shape guided-mode resonance (GMR) in waveguide gratings. Both the models constitute a resonant tank circuit together with a direct non-resonant channel between the incident and scattered light. One neglects the frequency dependence of the direct non-resonant channel and is only more accurate in the immediate vicinity of the Fano-type resonance. The other accounts for the frequency dependence of the direct non-resonant channel and thus remains accurate within a wider range of frequencies. The former being referred to as the narrow-band model is extremely accurate, insofar as the isolated GMR is of interest within a...
An efficient uniform-segmented neuron model for large-scale neuromorphic circuit design: Simulation and FPGA synthesis results
, Article IEEE Transactions on Circuits and Systems I: Regular Papers ; Volume 66, Issue 6 , 2019 , Pages 2336-2349 ; 15498328 (ISSN) ; Abolfathi, H ; Ahmadi, A ; Ahmadi, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Large-scale simulation of spiking neural networks on hardware with a remarkable resemblance to their mathematical models is a key objective of the neuromorphic discipline. This issue is, however, considerably resource-intensive due to the presence of nonlinear terms in neuron models. This paper proposes a novel uniform piecewise linear segmentation approach for nonlinear function evaluations. Employing the proposed approach, we present a uniform-segmented adaptive exponential neuron model capable of accurately producing various responses exhibited by the original model and suitable for efficient large-scale implementation. In contrast to previous nonuniform-segmented neuron models, the...
A robust short-circuit fault diagnosis for high voltage DC power supply based on multisensor data fusion
, Article 10th International Power Electronics, Drive Systems and Technologies Conference, PEDSTC 2019, 12 February 2019 through 14 February 2019 ; 2019 , Pages 659-664 ; 9781538692547 (ISBN) ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Short-circuit fault (SCF) detection is mandatory in a high voltage DC power supply (HVPS) to prevent fatal damage. The majority of converters employ a single sensor to detect the SCF. This attribute increases the interference vulnerability of the fault detection (FD) 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 FD due to the filter delay. This paper proposes a fast FD algorithm based on...
IGBT Open-circuit fault diagnosis in a quasi-z-source inverter
, Article IEEE Transactions on Industrial Electronics ; Volume 66, Issue 4 , 2019 , Pages 2847-2856 ; 02780046 (ISSN) ; Moghani, J. S ; Noroozi, N ; Zolghadri, M. R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, a fast and practical method is proposed for open-circuit (OC) fault diagnosis (FD) in a three-phase quasi-Z-source inverter (q-ZSI). Compared with the existing fast OC FD techniques in three-phase voltage source inverters, this method is more cost-effective since no ultrafast processor or high-speed measurement is required. Additionally, the method is independent of the load condition. The proposed method is only applicable to Z-source family inverters and is based on observing the effect of shoot-through intervals on the system variables during switching periods. The proposed algorithm includes two consecutive stages: OC detection and fault location identification. When both...
Proposal of an analytical model for performance evaluation of WR -resolvers under short circuit fault
, Article 27th Iranian Conference on Electrical Engineering, ICEE 2019, 30 April 2019 through 2 May 2019 ; 2019 , Pages 486-490 ; 9781728115085 (ISBN) ; Nasiri Gheidari, Z ; Tootoonchian, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Wound-Rotor (WR) resolvers are the most widely used position sensors in applications with harsh environmental conditions. However, their performance is exposed to failure due to high risk of short circuit (SC) fault. Although the output current of the resolver is negligible, its thin copper wires increases the probability of the short circuit fault. To avoid the propagation of the turn-to turn SC fault to the whole coil and undesirable performance of the motion control drive, it is necessary to diagnose it at the very beginning of its development. Meanwhile, the first step of diagnosing faults is their modeling. Time stepping finite element analysis is the most accurate, but computationally...
HTS transformer windings design using distributive ratios for minimization of short circuit forces
, Article Journal of Superconductivity and Novel Magnetism ; Volume 32, Issue 2 , 2019 , Pages 151-158 ; 15571939 (ISSN) ; Vakilian, M ; Hekmati, A ; Fardmanesh, M ; Sharif University of Technology
Springer New York LLC
2019
Abstract
High-temperature superconducting (HTS) transformers have a promising feature in reduction of total weight, total size, and the losses of large-scale distribution transformers. However, the lower leakage reactance of HTS transformers results in a higher short-circuit fault currents and electromagnetic forces. Therefore, optimization of short-circuit electromagnetic forces is one of the crucial aspects in the design of HTS transformers. In this paper, a novel analytical method is proposed for determination of optimum distributive ratios resulting in minimization of these forces for asymmetrical multi-segment windings of an HTS transformer. Employing these distributive ratios, radial and axial...
Wide-and narrow-band circuit models for fano-shape guided mode resonance
, Article IEEE Journal of Quantum Electronics ; 2019 ; 00189197 (ISSN) ; Memarian, M ; Mehrany, K ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, we propose two different types of circuit models for Fano-shape guided mode resonance (GMR) in waveguide gratings. Both models constitute a resonant tank circuit together with a direct non-resonant channel between the incident and the scattered light. One neglects the frequency dependence of the direct non-resonant channel and is only more accurate in the immediate vicinity of the Fano type resonance. The other accounts for the frequency dependence of the direct non-resonant channel and thus remains accurate within a wider range of frequencies. The former being referred to as the narrow-band model is extremely accurate insofar as the isolated GMR is of interest within a narrow...
Wide-and narrow-band circuit models for fano-shape guided mode resonance
, Article IEEE Journal of Quantum Electronics ; 2019 ; 00189197 (ISSN) ; Memarian, M ; Mehrany, K ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, we propose two different types of circuit models for Fano-shape guided mode resonance (GMR) in waveguide gratings. Both models constitute a resonant tank circuit together with a direct non-resonant channel between the incident and the scattered light. One neglects the frequency dependence of the direct non-resonant channel and is only more accurate in the immediate vicinity of the Fano type resonance. The other accounts for the frequency dependence of the direct non-resonant channel and thus remains accurate within a wider range of frequencies. The former being referred to as the narrow-band model is extremely accurate insofar as the isolated GMR is of interest within a narrow...
Development of a three-dimensional magnetic equivalent circuit model for axial flux machines
, Article IEEE Transactions on Industrial Electronics ; Volume 67, Issue 7 , 2020 , Pages 5758-5767 ; Nasiri Gheidari, Z ; Oraee, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
Numerical and analytical methods are two methods to evaluate the performance of electrical machines. This article provides a comparison between numerical and analytical methods. Electrical machine software typically uses numerical methods to solve the electromagnetic equations. On the other hand, analytical methods are faster and more intuitive. A general analytical modeling technique to evaluate the performance of axial flux machines including but not limited to wound rotor resolvers is presented here. The proposed model is based on the actual three-dimensional (3-D) magnetic equivalent circuit (MEC). The accuracy of the proposed model depends on the number of radial layers in the...
Investigating critical parameters for bioremoval of heavy metals from computer printed circuit boards using the fungus Aspergillus niger
, Article Hydrometallurgy ; Volume 197 , 2020 ; Esmaeili, A ; Yaghmaei, S ; Sharif University of Technology
Elsevier B.V
2020
Abstract
In this article, bioleaching of computer printed circuit boards (CPCBs) was examined using Aspergillus niger with one-step, two-step, and spent-medium bioleaching methods. Four effective parameters were optimized using response surface methodology (RSM) to achieve maximum recovery of Cu and Ni. Under optimal conditions – pH of 5.15, pulp density of 10 g/l, 1E+007 spores of A.niger, and 4.5 days for the sample adding time − 97% and 74% of Cu and Ni were recovered, respectively. Two-step bioleaching and spent medium bioleaching were respectively identified as the best methods for maximizing Cu and Ni recovery. Fungi deteriorate the sample mainly by it is chemical action like producing acids....
Evaluating the optimal digestion method and value distribution of precious metals from different waste printed circuit boards
, Article Journal of Material Cycles and Waste Management ; Volume 22, Issue 5 , 2020 , Pages 1690-1698 ; Yaghmaei, S ; Esmaeili, A ; Sharif University of Technology
Springer
2020
Abstract
Knowing the metal content of electronic waste is essential to evaluate metal recovery. Lack of a standard method for digestion of precious metals from electronic waste has resulted in difficulty in comparison to the efficiency of recovery. In this study, different precious metal digestion methods and economic value of precious metals from different types of waste printed circuit boards in different fraction sizes, including computer printed circuit boards, mobile phone printed circuit boards, television printed circuit boards, fax machine printed circuit boards, copy machine printed circuit boards, and central processing unit were examined. The optimal digestion method using aqua regia,...
Detecting the location of short-circuit faults in active distribution network using pmu-based state estimation
, Article IEEE Transactions on Smart Grid ; Volume 11, Issue 2 , 2020 , Pages 1396-1406 ; Abbaspour, A ; Moeini Aghtaie, M ; Fotuhi Firuzabad, M ; Lehtonen, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
With the rapid advancement of phasor measurement units (PMUs) technology, system operators in different level of power systems have access to new and abundant measurements. Taking into account these measurements in active distribution systems (ADNs), a new algorithm for short-circuit fault detection and identification based on state estimation (SE) is introduced in this paper. In this regard, as the first step, traditional SE process is revised to be compatible with fault conditions. Then, a fault location algorithm (FLA) based on the revised SE (RDSSE) is presented which attends to detect the location of fault after diagnosing faulted zone. For this purpose, current and voltage...
Self-Powered soil moisture monitoring sensor using a picoampere quiescent current wake-up circuit
, Article IEEE Transactions on Instrumentation and Measurement ; Volume 69, Issue 9 , 2020 , Pages 6613-6620 ; Habibi, M ; Magierowski, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
Low-power wireless stand-alone sensors that can operate without any wiring have received significant attention in sensor network applications. These devices harvest environmental energy resources to supply their power and transfer their collected data using wireless RF links. In many instances, the power supplied from the environment is far less than the power required by the sensor device. In this case, the main solution is to accumulate energy on a storage element, and when enough energy is stored, the sensor node is instantaneously activated using an undervoltage lockout (UVLO) circuit. During this short time burst, the sensor performs the required acquisition, transmits the results, and...
HTS transformers leakage flux and short circuit force mitigation through optimal design of auxiliary windings
, Article Cryogenics ; Volume 110 , September , 2020 ; Vakilian, M ; Hekmati, A ; Fardmanesh, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Mitigation and control of leakage fluxes and short circuit forces needs much more attention, for a high-temperature superconducting (HTS) transformer, than for a conventional one. Different methods such as the application of auxiliary windings, multi-segment winding, and flux diverter have been presented in the literatures for leakage magnetic field reduction in HTS transformers. In this paper, for the first time, optimal design of auxiliary windings has been performed for a 132/13.8 kV, 50 MVA three phase core type HTS transformer. Genetic algorithm (GA) has been used for the optimization process. Induced current in auxiliary windings which is inversely proportional to the leakage fluxes...
Optimal design of flux diverter using genetic algorithm for axial short circuit force reduction in HTS transformers
, Article IEEE Transactions on Applied Superconductivity ; Volume 30, Issue 1 , January , 2020 ; Vakilian, M ; Hekmati, A ; Fardmanesh, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
The appealing advantages of high-temperature superconducting (HTS) power transformers over conventional ones have attracted transformer manufacturing companies, power companies, research institutes, and universities worldwide to conduct research and development in this field. Unfortunately, HTS transformers are more vulnerable to mechanical stresses than conventional transformers. The results of the interaction between current carrying windings and leakage magnetic fluxes are the electromagnetic forces, which act on transformer windings. Under short circuit events, these forces are remarkable, and, therefore, catastrophic failure of transformer may arise. Flux-diverter applications have been...