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Analysis and Enhancement of Low Voltage Ride Through Of Wind Turbines with Brushless Doubly Fed Induction Generator
, Ph.D. Dissertation Sharif University of Technology ; Oraee Mirzamani, Hashem (Supervisor) ; Tohidi, Sajjad (Co-Advisor)
Abstract
Wind energy technologies guarantee low pollution and operational costs. Using a DFIG and a fractionally rated power electronics converter gives variable speed operation with a low cost drive train. As energy policy organizations have allocated a considerable quota of wind energy generation to offshore wind farms, the absence of slip rings and brushes in the brushless DFIG (BDFIG) is an advantage for offshore wind turbines where maintenance is vital and expensive. With increasing wind power penetration in power systems, grid code requirements are an important consideration for the ride-through capability of wind farms through voltage dips, particularly for multi- MW wind turbine generators....
Analysis and Improvement of Dynamic Performance and Fault Ride-Through Capability of Wind Turbines Based on Doubly-Fed Induction Generators
, Ph.D. Dissertation Sharif University of Technology ; Parniani, Mostafa (Supervisor)
Abstract
Variable speed wind turbines (VSWTs) provide the capability of wide speed operation and independent control of active and reactive power. In contrast to the fixed speed WTs, they have higher efficiency, power quality and controllability. VSWTs are mainly divided in two categories: WTs based on doubly fed induction generator (DFIG) and WTs based on full converter with permanent magnet synchronous generator.
At now, among the different alternatives to obtain VSWTs, DFIGs are the most commonly used. This is because the voltage source converter (VSC) in DFIG has to handle a fraction of the total power under steady state conditions, and thus the size and cost of the converter is reduced....
At now, among the different alternatives to obtain VSWTs, DFIGs are the most commonly used. This is because the voltage source converter (VSC) in DFIG has to handle a fraction of the total power under steady state conditions, and thus the size and cost of the converter is reduced....
Design and Fabrication of a Wearable Plantar Pressure Measuring System Using Force Sensing Resistor (FSR)
, M.Sc. Thesis Sharif University of Technology ; Farahmand, Farzam (Supervisor) ; Narimani, Roya (Supervisor)
Abstract
The recent project can be considered as a subset of Telerehabilitation, in the field of Telerehabilitation can be defined as the need for long-term data recording in order to determine each individual's movement pattern and compare it to the individual's best model or best practice. With this perspective, it can be said that the recent project, in more detail, remotely targets the use of foot plantar pressure to determine locomotor parameters. With this description, the FSR or force sensitive resistor sensor was selected for a number of reasons, including low cost, low weight and low thickness, and the data acquisition circuit was used to convert the sensors' analog signal to digital output,...
Influence of different series dynamic resistors on low-voltage ride-through of brushless doubly fed induction generator
, Article Electric Power Components and Systems ; Volume 43, Issue 8-10 , 2015 , Pages 995-1005 ; 15325008 (ISSN) ; Oraee, H ; Zolghadri, M. R ; Tavner, P. J ; Sharif University of Technology
Taylor and Francis Inc
2015
Abstract
The brushless doubly fed induction generator has been proposed for use in wind turbines as a more reliable alternative to the more commonly used doubly fed induction generator. To realize the commercial promises of the brushless doubly fed induction generator in this role, it must meet the existing grid connection codes, particularly with respect to low-voltage ride-through. In this article, the application of series dynamic resistors is proposed to enhance brushless doubly fed induction generator low-voltage ride-through capability, and the required analysis is provided. Three locations for series dynamic resistors are suggested in the brushless doubly fed induction generator circuit and...
Passively realisable impedance functions by using two fractional elements and some resistors
, Article IET Circuits, Devices and Systems ; Volume 12, Issue 3 , 2018 , Pages 280-285 ; 1751858X (ISSN) ; Sharif University of Technology
Institution of Engineering and Technology
2018
Abstract
Here, the necessary and sufficient conditions for realisability of a general class of impedance functions by passive electrical networks composed of two fractional element (fractional capacitor or fractional inductor) and some resistors are found. Also, a systematic procedure is proposed to obtain such passive electrical networks in the realisable cases. Moreover, by establishing a connection with the previously reported researches on the subject of inerter-based passive mechanical control, further results on the maximum number of the resistors required for passive realisation are obtained. Furthermore, a numerical example is presented to show the usefulness of the paper achievements in...
Temperature compensation in CMOS peaking current references
, Article IEEE Transactions on Circuits and Systems II: Express Briefs ; Volume 65, Issue 9 , 2018 , Pages 1139-1143 ; 15497747 (ISSN) ; Kananian, S ; Sharifkhani, M ; Sodagar, A. M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
In this brief, modifications to the peaking current reference with MOS transistors operating in the subthreshold and the strong inversion region has been proposed by means of which very small currents with immunity to temperature variations on a chip can be obtained. Temperature compensation can be done by adding a source degeneration resistor to the conventional peaking current source structure. Design examples are provided for both weak and strong inversion operations with output currents of 1.5 μA and 40 μ A with less than 4% and 10% variation over the span of-40 °C to +100 °C, respectively. A prototype of the circuit operating in the weak and strong inversion region is designed,...
A series stacked IGBT switch with robustness against short-circuit fault for pulsed power applications
, Article IEEE Transactions on Power Electronics ; Volume 33, Issue 5 , May , 2018 , Pages 3779-3790 ; 08858993 (ISSN) ; Zarghany, M ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
The limited value of the insolated-gate bipolar transistors (IGBTs) blocking voltage is an important issue for applying these devices to the high-voltage power converters. An effective solution is to use a series configuration of these devices in order to achieve higher voltage ratings in addition to save the interesting features such as fast rising time. To reach this goal, acceptable equal voltage sharing for the IGBTs are provided by the series stacking schemes in the normal operation.However, a considerable difference in their voltage level will be occurred in the short-circuit condition. Although the IGBT can withstand the short-circuit current in a defined time, the occurred high...
A comprehensive design of the thyristor-based crowbar for vacuum tube high-voltage dc power supplies
, Article IEEE Transactions on Plasma Science ; Volume 48, Issue 6 , 2020 , Pages 2202-2209 ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
High-voltage power supplies (HVPSs) are widely used to drive vacuum tubes, inherently susceptible to vacuum arc faults. Owing to the considerable cost of vacuum tubes, the HVPS should enjoy a reliable, fast protection mechanism. A common protection mechanism against vacuum arc faults is the shunt crowbar. The crowbar diverts the energy stored in the elements of the HVPS through itself as a parallel path, thereby protecting vacuum tubes from irrecoverable damages. Among all types of the shunt crowbar, the thyristor-based crowbar along with the fault current limiter (FCL) resistors attracts more attention because of its more reliable operation. The absence of the comprehensive design procedure...
An 8-bit switched-resistor pipeline ADC
, Article 2007 IEEE International Symposium on Circuits and Systems, ISCAS 2007, New Orleans, LA, 27 May 2007 through 30 May 2007 ; 2007 , Pages 1963-1966 ; 02714310 (ISSN) ; Sharif Bakhtiar, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2007
Abstract
In this paper a new technique called switched-resistor is used as an alternative to switched-capacitor circuits in a low-voltage low-power high-speed A/D converter. Simulation results for an 8-bit 150MS/s pipeline ADC are presented. This converter consumes 20mW from a 1.8V supply and provides an ENOB of 7.5bit. © 2007 IEEE
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...
Performance analysis of the lithium-ion battery RC equivalent circuit model using EPA drive cycles
, Article 13th Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2022, 1 February 2022 through 3 February 2022 ; 2022 , Pages 393-397 ; 9781665420433 (ISBN) ; Zolghadri, M ; Kia, S. H ; El Hajjaji, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
This paper compares the dynamic and static models of a Lithium-ion battery pack with its electrochemical model as energy storage of an electric vehicle according to the environmental protection agency drive cycles. The dynamic model or the RC equivalent circuit includes a voltage source and double parallel resistor and capacitor networks which are connected in series. The static model includes a voltage source and resistors. Given drive cycles, these models are compared in terms of the battery voltage, state-of-charge, and power loss in an electric vehicle in MapleSim software. Although the state-of-charge and power loss of both models are identical to each other, actually the terminal...
Application of packet control method for a high power high voltage flyback converter to reduce noise influence
, Article 2005 European Conference on Power Electronics and Applications, Dresden, 11 September 2005 through 14 September 2005 ; Volume 2005 , 2005 , Pages 10-19 ; 9075815085 (ISBN); 9789075815085 (ISBN) ; Sadriyeh, S. M. R ; Mohammadi, A ; Zolghadri, M. R ; Emadi, A ; Sharif University of Technology
IEEE Computer Society
2005
Abstract
In the regulated switching power supplies, the output voltage is usually sampled across a resistive voltage divider. In high voltage applications, the resistance of the voltage divider is very high in order to reduce its power loss. Therefore, these resistors are very good receivers of environment noise. This paper introduces a new control method for a high power, high voltage Flyback converter insensitive to the noise caused by ringing due to the leakage reactance of a high voltage Flyback converter. In this method, output voltage is sampled in an intentionally extended cycle to be sure that all the oscillations are damped. Therefore there is no need to additional damping circuits and...
Low voltage ride-through capability improvement of DFIG-based wind turbines under unbalanced voltage dips
, Article International Journal of Electrical Power and Energy Systems ; Vol. 60,Issue , 2014 , pp. 82-95 ; ISSN: 01420615 ; Parniani, M ; Sharif University of Technology
Abstract
This paper proposes a competent and effective scheme to enhance the ride-through capability of DFIG-based wind turbines under unbalanced voltage dip conditions. The proposed method is realized through joint use of the rotor-side converter control and a three-phase stator damping resistor (SDR) placed in series with the stator windings. By means of an asymmetrical SDR idea, during the unbalanced voltage dip the SDR resistors are activated only in phase(s) experiencing low voltage. Then, the rotor current is controlled such that no unbalance voltage appears on the stator voltage. The proposed ride-through approach limits the peak values of the rotor inrush current, electromagnetic torque and...
A novel hardware implementation for joint heart rate, respiration rate, and gait analysis applied to body area networks
, Article Proceedings - IEEE International Symposium on Circuits and Systems ; 2013 , Pages 1889-1892 ; 02714310 (ISSN) ; 9781467357609 (ISBN) ; Zamani, A. R ; Hallajian, M ; Ehsani, S. P ; Moghaddam, H. A ; Parsafar, A ; Shabany, M ; Sharif University of Technology
2013
Abstract
Continuous and remote monitoring of vital health-related and physical activity signs of a patient is one of the most important technology-oriented applications to monitor the health-care of ill individuals. In this paper, an innovative framework for a wireless Body Area Network (BAN) system, based on the IEEE 802.15.6 standard, with three types of sensors is proposed and implemented. These include Electrocardiogram (ECG), Force Sensitive Resistor (FSR) and Gyroscope. The proposed design is a novel implementation of an embedded system for the real-time processing and analyzing of the ECG signal, gait phases, and detection of the respiration rate from the ECG signal, by means of small...
Analysis and enhancement of low-voltage ride-through capability of brushless doubly fed induction generator
, Article IEEE Transactions on Industrial Electronics ; Volume 60, Issue 3 , March , 2013 , Pages 1146-1155 ; 02780046 (ISSN) ; Oraee, H ; Zolghadri, M. R ; Shao, S ; Tavner, P ; Sharif University of Technology
2013
Abstract
This paper discusses the dynamic behavior of the brushless doubly fed induction generator during the grid faults which lead to a decrease in the generator's terminal voltage. The variation of the fluxes, back EMFs, and currents are analyzed during and after the voltage dip. Furthermore, two alternative approaches are proposed to improve the generator ride-through capability using crowbar and series dynamic resistor circuits. Appropriate values for their resistances are calculated analytically. Finally, the coupled circuit model and the generator's speed and reactive power controllers are simulated to validate the theoretical results and the effectiveness of the proposed solutions. Moreover,...
Simulation of memristor crossbar structure on GPU platform
, Article ICEE 2012 - 20th Iranian Conference on Electrical Engineering, 15 May 2012 through 17 May 2012 ; May , 2012 , Pages 178-183 ; 9781467311489 (ISBN) ; Shouraki, S. B ; Soleimani, H ; Ahmadi, A ; Makhlooghpour, A. A ; Sharif University of Technology
2012
Abstract
Memristive devices have gained significant research attention lately because of their unique properties and wide application spectrum. In particular, memristor-based resistive random access memory (RRAM) offers the high density, low power, and low volatility required for next-generation nonvolatile memory. Nowadays, despite significant advances in hardware technology, in the case of massively parallel systems still new computational architectures are required. Simulation of large quantity of memristors in the crossbar structure is a known challenge encountering these barriers. Using graphic processing units (GPU) as a low-cost and high-performance computing platform is an efficient preferred...
Memristor crossbar-based hardware implementation of the IDS method
, Article IEEE Transactions on Fuzzy Systems ; Volume 19, Issue 6 , Dec , 2011 , Pages 1083-1096 ; 10636706 (ISSN) ; Shouraki, S. B ; Rohani, A ; Sharif University of Technology
2011
Abstract
Ink drop spread (IDS) is the engine of an active learning method, which is the methodology of soft computing. IDS, as a pattern-based processing unit, extracts useful information from a system that is subjected to modeling. In spite of its excellent potential to solve problems such as classification and modeling compared with other soft-computing tools, finding its simple and fast hardware implementation is still a challenge. This paper describes a new hardware implementation of the IDS method that is based on the memristor crossbar structure. In addition to simplicity, being completely real time, having low latency, and the ability to continue working properly after the occurrence of power...
Memristor crossbar-based hardware implementation of fuzzy membership functions
, Article Proceedings - 2011 8th International Conference on Fuzzy Systems and Knowledge Discovery, FSKD 2011, 26 July 2011 through 28 July 2011 ; Volume 1 , July , 2011 , Pages 645-649 ; 9781612841816 (ISBN) ; Shouraki, S. B ; Merrikh Bayat, F ; Sharif University of Technology
2011
Abstract
In May 1, 2008, researchers at Hewlett Packard (HP) announced the first physical realization of a fundamental circuit element called memristor that attracted so much interest worldwide. This newly found element can easily be combined with crossbar interconnect technology which this new structure has opened a new field in designing configurable or programmable electronic systems. These systems in return can have applications in signal processing and artificial intelligence. In this paper, based on the simple memristor crossbar structure, we propose new and simple circuits for hardware implementation of fuzzy membership functions. In our proposed circuits, these fuzzy membership functions can...
Programming of memristor crossbars by using genetic algorithm
, Article Procedia Computer Science, 6 October 2010 through 10 October 2010 ; Volume 3 , October , 2011 , Pages 232-237 ; 18770509 (ISSN) ; Shouraki, S. B ; Sharif University of Technology
2011
Abstract
Recently announcement of a physical realization of a fundamental circuit element called memristor by researchers at Hewlett Packard (HP) attracted so much interests and opened a new field in configurable or programmable electronic systems because it has properties of the perfect switch. Combination of this newly found circuit element with nanowire crossbar interconnect technology, creates a powerful platform which is called memristor crossbar. It has been demonstrated that this structure can offer the potential of creating configurable electronic devices which can have applications in signal processing and artificial intelligence. In this paper, we will highlight the rule that Genetic...
Memristor-based circuits for performing basic arithmetic operations
, Article Procedia Computer Science, 6 October 2010 through 10 October 2010 ; Volume 3 , October , 2011 , Pages 128-132 ; 18770509 (ISSN) ; Shouraki, S. B ; Sharif University of Technology
2011
Abstract
In almost all of the currently working circuits, especially in analog circuits implementing signal processing applications, basic arithmetic operations such as multiplication, addition, subtraction and division are performed on values which are represented by voltages or currents. However, in this paper, we propose a new and simple method for performing analog arithmetic operations which in this scheme, signals are represented and stored through a memristance of the newly found circuit element, i.e. memristor, instead of voltage or current. Some of these operators such as divider and multiplier are much simpler and faster than their equivalent voltage-based circuits and they require less...