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power-electronics
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Modeling, control and voltage unbalance compensation in a four-switch rectifier with input power factor correction
, Article PEDSTC 2013 - 4th Annual International Power Electronics, Drive Systems and Technologies Conference ; 2013 , Pages 148-152 ; 9781467344845 (ISBN) ; Shahbazi, M ; Zolghadri, M ; Sharif University of Technology
2013
Abstract
In this paper, a small signal model is proposed for four-switch rectifier with input power factor correction. The required transfer functions are determined and calculated for a typical rectifier. This model is used to design an appropriate controller with defined characteristic to improve the rectifier performance. Another controller is used to compensate capacitors dc voltage difference. The system is simulated in Simulink and the results are provided. These results confirm the accuracy of the developed model, and also the effectiveness of the proposed controllers
Analyzing and modeling of a new resonance inverter for low power vehicular application
, Article PECon 2012 - 2012 IEEE International Conference on Power and Energy ; 2012 , Pages 576-581 ; 9781467350198 (ISBN) ; Keipour, A ; Sudi, Z ; Moallemi, M ; Hajihosseinlu, A ; Sharif University of Technology
2012
Abstract
In this paper we proposed a novel inverter to convert a DC voltage to a desired AC voltage. This inverter is designed for variable inductive loads and low output power applications. We proposed a novel simple PWM method which enables the inverter to keep the output current at six times more than the rated output current, without reducing output voltage value. In addition, based on a simple use of resonance in the circuit, the new inverter can raise the output voltage to extremely high amplitude for a relatively short time. These characteristics make the proposed inverter is useful for some industrial applications such as electrical vehicle. The new configuration of the circuit consists of a...
Output voltage quality intensification of diode clamped multilevel inverters using FM PWM technique
, Article 2012 3rd Power Electronics and Drive Systems Technology, PEDSTC 2012, 15 February 2012 through 16 February 2012 ; February , 2012 , Pages 98-102 ; 9781467301114 (ISBN) ; Ebrahimi, S ; Oraee, H ; Sharif University of Technology
2012
Abstract
Improvement in switching techniques is one of the effective methods for increasing the voltage quality in Multilevel Inverters. In this paper, a novel switching technique using frequency modulation is proposed to achieve high quality output voltage of multilevel inverters. This method is employed to different configurations of multilevel inverters consist of Diode Clamped (or Neutral Point Clamped), Flying Capacitor and Cascaded H-bridge. Each multilevel inverter which utilizes this technique is modeled and simulated to investigate the performance of this method by the help of MATLAB/Simulink software. The Results show that this innovative method considerably reduces total harmonic...
A combinational logic optimization for majority gate-based nanoelectronic circuits based on GA
, Article 2011 International Semiconductor Device Research Symposium, ISDRS 2011, College Park, MD, 7 December 2011 through 9 December 2011 ; 2011 ; 9781457717550 (ISBN) ; Kamrani, M ; Sayedsalehi, S ; Navi, K ; Sharif University of Technology
Abstract
Quantum dots cellular automata is a new computing method in the nanotechnology that has considerable features such as low power, small dimension and high speed switch. A QCA device stores logic based on the position of individual electrons. The fundamental logic elements in QCA are the majority (Fig.1 (a)) and inverter gates (Fig.1 (b)) that operate based on the Coulomb repulsion between electrons [1]
Modeling, control and islanding detection of microgrids with passive loads
, Article Proceedings of EPE-PEMC 2010 - 14th International Power Electronics and Motion Control Conference, 6 September 2010 through 8 September 2010 ; September , 2010 , Pages T11107-T11112 ; 9781424478545 (ISBN) ; Karimi, H ; Nikkhajoei, H ; Terzija, V ; Sharif University of Technology
2010
Abstract
This paper presents a control scheme for microgrids with passive loads. The existing control techniques for distributed generation systems are designed to operate either in the grid-connected or in the islanded mode. In the grid-connected mode of operation, a currentcontrolled scheme based on d-q variables is used for the regulation of real and reactive powers of the converter. In the islanded mode of operation, the converter is controlled in the voltage-controlled mode. This paper deals with the modeling of both control schemes. Furthermore, reconnection from the islanded mode to the grid-connected mode based on the use of adequate Phase-Locked Loops (PLLs) has been demonstrated
Dynamic model for Brushless Doubly-Fed Machine with stator winding faults
, Article PEDSTC 2010 - 1st Power Electronics and Drive Systems and Technologies Conference, 17 February 2010 through 18 February 2010 ; February , 2010 , Pages 316-322 ; 9781424459728 (ISBN) ; Sotoodeh, P ; Oraee, H ; Sharif University of Technology
2010
Abstract
In this paper, a detailed analytical model for dynamic analysis of the Brushless Doubly-Fed Machine is presented. The model is capable to predict the machine behavior under different modes of operation including: simple induction mode, cascade mode and synchronous mode, both with and without winding faults and unbalanced excitations. The proposed approach employs the basic principles of the generalized harmonic theory for calculating self inductances and mutual inductances of circuits with any distribution of conductors. Dynamic equations of modified coupled-circuit method are then solved to compute the currents flowing in the stator windings and rotor loops
Stability analysis and experimental validation of a control strategy for autonomous operation of distributed generation units
, Article 2010 International Power Electronics Conference - ECCE Asia -, IPEC 2010, 21 June 2010 through 24 June 2010 ; June , 2010 , Pages 464-471 ; 9781424453955 (ISBN) ; Karimi, H ; Iravani, R ; IEEJ ; Sharif University of Technology
2010
Abstract
This paper presents stability analysis of a distributed generation (DG) controller [1], in an islanded mode, based on the Mapping Theorem and the Zero Exclusion Condition, and validates the results based on a laboratory scale experimental setup. The DG unit is interfaced to the host system through a voltage-sourced converter (VSC). The control strategy regulates the load voltage at the desired value in the islanded mode, despite uncertainties in the load parameters. The frequency of the island is controlled in an open loop manner by an internal oscillator. The experimental results show that the controller provides robust voltage control for a wide range of load parameters, and even maintains...
Compensation method for multistage opamps with high capacitive load using negative capacitance
, Article IEEE Transactions on Circuits and Systems II: Express Briefs ; Volume 63, Issue 10 , 2016 , Pages 919-923 ; 15497747 (ISSN) ; Sharif Bakhtiar, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Abstract
It is shown that negative capacitance (NC) circuits can be systematically used to improve the gain-bandwidth product of the operational amplifiers (opamps). The NC circuit moves the nondominant pole of the opamp to higher frequency by decreasing the parasitic capacitance of the critical node. The impedance at the input of the NC circuits is neither purely capacitive nor negative at all frequencies. A design guide is presented by deriving the circuit model for a conventional NC circuit and investigating the extent of the improvement that can be achieved in a circuit by the use of the NC circuit. The model is then used to present the design guide for widebanding the multistage opamps with...
RCD snubber design based on reliability consideration: A case study for thermal balancing in power electronic converters
, Article Microelectronics Reliability ; Volume 88-90 , 2018 , Pages 1311-1315 ; 00262714 (ISSN) ; Zarghani, M ; Kaboli, S ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In a turn-off RCD snubber, the capacitor value is usually optimized in order to minimize the power dissipated in the switch and snubber circuit. However, it may not be the best value of the snubber capacitor from the reliability point of view. In this paper, the capacitor value is optimized based on reliability considerations. Proposed method presents a new design to achieve the maximum reliability for the set of switch and its snubber. Mathematical analysis of the proposed method is conducted in MATLAB environment. Also, the experimental results are presented for validity of the theoretical analysis. © 2018 Elsevier Ltd
SPONGE: a scalable pivot-based on/off gating engine for reducing static power in NoC routers
, Article Proceedings of the International Symposium on Low Power Electronics and Design23 July 2018 ; 23-25 July , 2018 ; 15334678 (ISSN) ; 9781450357043 (ISBN) ; Mardani Kamali, H ; Jerger, N. E ; Hessabi, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Due to high aggregate idle time of Networks-on-Chip (NoCs) routers in practical applications, power-gating techniques have been proposed to combat the ever-increasing ratio of static power. Nevertheless, the sporadic packet arrivals compromise the effectiveness of power-gating by incurring significant latency and energy overhead. In this paper, we propose a Scalable Pivot-based On/Off Gating Engine (SPONGE) which efficiently manages power-gating decisions and routing mechanism by adaptively selecting a small set of powered-on columns of routers and keeping the others in power-gated state. To this end, a router architecture augmented with a novel routing algorithm is proposed in which a...
Enhanced control of grid forming VSCs in a micro-grid system under unbalanced conditions
, Article 9th Annual International Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2018, 13 February 2018 through 15 February 2018 ; Volume 2018-January , April , 2018 , Pages 380-385 ; 9781538646977 (ISBN) ; Mokhtari, H ; Ghasemi, M. A ; SHarif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Due to the technical advances in power electronic industry, employing inverter-based distributed energy resources (IBDERs) are increased in electric power systems. Distributed generators (DGs) with the rating capacity of few megawatts are commonly connected to the distribution level of power systems which are inherently unbalanced. A cluster of IBDERs and loads form a small-scale grid called microgrid (MG) which can operate independent of the main grid. In a MG, grid forming voltage source converters (VSCs) are used to control the voltages and frequency of the MG. However, grid forming VSCs with conventional control schemes cannot do this task properly when the MG is unbalanced. In this...
On the suitability of modeling approaches for power electronic converters
, Article International Symposium on Industrial Electronics 2006, ISIE 2006, Montreal, QC, 9 July 2006 through 13 July 2006 ; Volume 2 , 2006 , Pages 1486-1491 ; 1424404975 (ISBN); 9781424404971 (ISBN) ; Kaboli, S ; Mahdavi, J ; Sharif University of Technology
2006
Abstract
This paper is a summary and in-depth evaluation of some popular models for power electronic converters. Proper examples are given to support the evaluation with a complete comparison between the actual and simulated results. The paper presents the effort behind the design and analysis of DC-DC Converters and discuses their features. Some advantages and disadvantages of the studied models and the complicities of the nonlinear structure of the switching function of the converters are explained here. The paper offers some useful criteria for future selection and development on different DC-DC Converters. © 2006 IEEE
On piecewise affined large-signal modeling of PWM converters
, Article 2006 IEEE International Conference on Industrial Technology, ICIT, Mumbai, 15 December 2006 through 17 December 2006 ; 2006 , Pages 1419-1423 ; 1424407265 (ISBN); 9781424407262 (ISBN) ; Mobed, M ; Molayee, B ; Sharif University of Technology
2006
Abstract
The most common technique for analysis and control of power electronics circuits is switch averaging. The model is not linear however, and often results in a multiplicative term in the state equations. Hence, it is common to perform a small signal linearization of the model about an operating point. Models obtained with such method involve considerable approximation, and produce results that are limited for higher performance designs. In this paper a Piecewise Affine Approximation (PWA) technique is introduced for modeling of switched circuits. Modeling of a DC-DC buck-boost converter is presented as an illustrative example to show the favorable properties and broad utility of this approach....
A hybrid control approach for LLC resonant converter
, Article 12th Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2021, 2 February 2021 through 4 February 2021 ; 2021 ; 9780738111971 (ISBN) ; Tahami, F ; Barzkar, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
In this paper, a novel hybrid control approach is proposed to control the LLC resonant converter. Since the converter consists of both continuous variables and logical variables, it is intrinsically hybrid. Apart from that, because of fast dynamics of the converter and the fact that there is no closed form solution for discontinuous conduction modes (DCM), modeling and control of the LLC resonant converter is still a challenge. In the authors' previous work, a systematic model was proposed for the converter, the direct piecewise affine model. In this paper, an appropriate controller based on the proposed model is represented and the design procedure is discussed in details; the block diagram...
A single-switch quadratic boost with stacked zeta converter
, Article 12th Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2021, 2 February 2021 through 4 February 2021 ; 2021 ; 9780738111971 (ISBN) ; Tarzamni, H ; Sabahi, M ; Khoun Jahan, H ; Mohammadsalehian, S ; Blaabjerg, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
A high step-up converter including one active switch is presented in the present work. The introduced structure is a combination of Quadratic boost converter and Zeta converter; therefore, it features low input and output current ripples. The energy of leakage inductor is inherently recovered and the voltage spike on switch is perfectly mitigated. The voltage across diodes and switch is quite lower than the boosted output voltage which can be a prominent issue in high step-up converters. This can lead to employ switches and diodes with low conduction losses causing overall efficiency to increase. The converter function in CCM and DCM are analyzed, and the voltage conversion ratio along with...
A low-power, multichannel gated oscillator-based CDR for short-haul applications
, Article 2005 International Symposium on Low Power Electronics and Design, San Diego, CA, 8 August 2005 through 10 August 2005 ; 2005 , Pages 107-110 ; 15334678 (ISSN) ; Muller, P ; Atarodi, M ; Leblebici, Y ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2005
Abstract
A gated current-controlled oscillator (GCCO) based topology is used to implement a low-power multi-channel clock and data recovery (CDR) system in a 0.18um digital CMOS technology. A systematic approach is presented to design a reliable and low-power system based on the required specifications. Behavioral simulations are also used to estimate the achievable bit error rate (BER), jitter tolerance (JTOL), and frequency offset tolerance (FTOL) of the proposed CDR. Using a single 1.8V supply voltage, the proposed 20Gbps 8-channel CDR consumes only 70.2mW or 3.51mW/Channel/Gbps while occupies 0.045mm2 silicon area. Copyright 2005 ACM
A new power management control strategy for a MV microgrid with both synchronous generator and inverter-interfaced distributed energy resources
, Article IEEE International Symposium on Industrial Electronics ; 1- 4 June , 2014 , pp. 2529-2534 ; ISBN: 978-147992399-1 ; Hamzeh, M ; Mokhtari, H ; Karimi, H ; Sharif University of Technology
Abstract
Control strategies of a microgrid which includes both synchronous generators and converter-based distribution generation (DG) units must be designed such that effective operation of the microgrid is achieved. The main objective of this paper is to develop a high performance control strategy for an islanded medium voltage (MV) microgrid consisting of inverter and non-inverter interfaced DG units. A new control method for the synchronous generator in an islanded microgrid is proposed based on a virtual droop scheme. The proposed strategy can effectively manage the real and reactive powers of the microgrid among the inverter and non-inverter based DG units. The steady state and dynamic...
Reliability assessment of some high side MOSFET drivers for buck converter
, Article 2013 3rd International Conference on Electric Power and Energy Conversion Systems, EPECS 2013, Istanbul ; 2013 ; 9781479906888 (ISBN) ; Kaboli, S ; Sharif University of Technology
2013
Abstract
Nowadays power electronic devices have a wide usage in the industries and different electrical equipment for power conditioning. As a point of view, reliability is one of important figure of merits that should be considered to have long life time and also have more probability to do exactly the proposed mission. In this paper some methods are presented to improve the reliability of power electronic components. Also some methods of system reliability improvement are reviewed. One group of converters is DC-DC step down converter which is used in different applications such as battery charger and voltage regulator. In this paper as an example, reliability of a DC-DC step down converter with...
Open-and short-circuit switch fault diagnosis for nonisolated DC-DC converters using field programmable gate array
, Article IEEE Transactions on Industrial Electronics ; Volume 60, Issue 9 , October , 2013 , Pages 4136-4146 ; 02780046 (ISSN) ; Jamshidpour, E ; Poure, P ; Saadate, S ; Zolghadri, M. R ; Sharif University of Technology
2013
Abstract
Fault detection (FD) in power electronic converters is necessary in embedded and safety critical applications to prevent further damage. Fast FD is a mandatory step in order to make a suitable response to a fault in one of the semiconductor devices. The aim of this study is to present a fast yet robust method for fault diagnosis in nonisolated dc-dc converters. FD is based on time and current criteria which observe the slope of the inductor current over the time. It is realized by using a hybrid structure via coordinated operation of two FD subsystems that work in parallel. No additional sensors, which increase system cost and reduce reliability, are required for this detection method. For...
μ-Synthesis control for an islanded microgrid with structured uncertainties
, Article IECON Proceedings (Industrial Electronics Conference), 7 November 2011 through 10 November 2011 ; November , 2011 , Pages 3064-3069 ; 9781612849720 (ISBN) ; Karimi, H ; Sharif University of Technology
2011
Abstract
This paper presents a robust control scheme for an islanded microgrid in the presence of structured uncertainties. The microgrid consists of parallel connection of two Distributed Generation (DG) units and a passive load. The DG units are connected to the passive load by using the power electronics converters. The microgrid model is structurally uncertain due to the large perturbations in the load parameters. To deal with the uncertainties, a Linear Fractional Representation (LFR) of the parametrically uncertain system is obtained. To achieve robust performance, the μ-synthesis approach is applied to the derived LFR model to design a μ controller. The resultant controller is structurally...