Search for: converter-reconfiguration
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    A wide dynamic range low power 2× time amplifier using current subtraction scheme

    , Article 2016 IEEE International Symposium on Circuits and Systems, ISCAS 2016, 22 May 2016 through 25 May 2016 ; Volume 2016-July , 2016 , Pages 462-465 ; 02714310 (ISSN); 9781479953400 (ISBN) Molaei, H ; Khorami, A ; Hajsadeghi, K ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2016
    The most challenging issue of conventional Time Amplifiers (TAs) is their limited Dynamic Range (DR). This paper presents a mathematical analysis to clarify principle of operation of conventional 2× TA's. The mathematical derivations release strength reduction of the current sources of the TA is the simplest way to increase DR. Besides, a new technique is presented to expand the Dynamic Range (DR) of conventional 2× TAs. Proposed technique employs current subtraction in place of changing strength of current sources using conventional gain compensation methods, which results in more stable gain over a wider DR. The TA is simulated using Spectre-rf in TSMC 0.18um COMS technology. DR of the 2×... 

    Fast fault detection method for modular multilevel converter semiconductor power switches

    , Article IET Power Electronics ; Volume 9, Issue 2 , 2016 , Pages 165-174 ; 17554535 (ISSN) Haghnazari, S ; Khodabandeh, M ; Zolghadri, M. R ; Sharif University of Technology
    Institution of Engineering and Technology  2016
    This study proposes a new fault detection method for modular multilevel converter (MMC) semiconductor power switches. While in common MMCs, the cells capacitor voltages are measured directly for control purposes, in this study voltage measurement point changes to the cell output terminal improving fault diagnosis ability. Based on this measurement reconfiguration, a novel fault detection algorithm is designed for MMCs semiconductor power switches. The open circuit and short circuit faults are detected based on unconformity between modules output voltage and switching signals. Simulation and experimental results confirm accurate and fast operation of the proposed method in faulty cell... 

    FPGA-based reconfigurable control for fault-tolerant back-to-back converter without redundancy

    , Article IEEE Transactions on Industrial Electronics ; Volume 60, Issue 8 , May , 2013 , Pages 3360-3371 ; 02780046 (ISSN) Shahbazi, M ; Poure, P ; Saadate, S ; Zolghadri, M. R ; Sharif University of Technology
    In this paper, an FPGA-based fault-tolerant back-to-back converter without redundancy is studied. Before fault occurrence, the fault-tolerant converter operates like a conventional back-to-back six-leg converter, and after the fault, it becomes a five-leg converter. Design, implementation, and experimental verification of an FPGA-based reconfigurable control strategy for this converter are discussed. This reconfigurable control strategy allows the continuous operation of the converter with minimum affection from a fault in one of the semiconductor switches. A very fast detection scheme is used to detect and locate the fault. Implementation of the fault detection and of the fully digital... 

    Open-circuit switch fault tolerant wind energy conversion system based on six/five-leg reconfigurable converter

    , Article Electric Power Systems Research ; Volume 137 , 2016 , Pages 104-112 ; 03787796 (ISSN) Shahbazi, M ; Saadate, S ; Poure, P ; Zolghadri, M ; Sharif University of Technology
    Elsevier Ltd  2016
    In this paper, an FPGA-controlled fault tolerant back-to-back converter for DFIG-based wind energy conversion application is studied. Before an open-circuit failure in one of the semiconductors, the fault tolerant converter operates as a conventional back-to-back six-leg one. After the fault occurrence in one of the switches, the converter will continue its operation with the remaining five healthy legs. Design, implementation, simulation and experimental verification of a reconfigurable control strategy for the fault tolerant six/five leg converter used in wind energy conversion are discussed. The proposed reconfigurable control strategy allows the uninterrupted operation of the converter... 

    An isolated bidirectional integrated plug-in hybrid electric vehicle battery charger with resonant converters

    , Article Electric Power Components and Systems ; Volume 44, Issue 12 , 2016 , Pages 1371-1383 ; 15325008 (ISSN) Ebrahimi, S ; Akbari, R ; Tahami, F ; Oraee, H ; Sharif University of Technology
    Taylor and Francis Inc  2016
    Plug-in hybrid electric vehicles draw electricity from the electrical grid and store energy in their batteries. To increase charge availability for plug-in hybrid electric vehicles, on-board chargers can be used, which should be small in size and lightweight. In this article, an on-board bidirectional soft-switched battery charger is proposed that utilizes a phase-shift-controlled dual-bridge series resonant converter with isolation. The bidirectional characteristic of proposed charger makes it suitable for vehicle-to-grid operation (i.e., injecting power from the vehicle to the grid) in smart grids. A switching control scheme is also proposed to provide soft-switching operation for all... 

    A four bit low power 165MS/s flash-SAR ADC for sigma-delta ADC application

    , Article IEEE International Conference on Electronics, Circuits, and Systems, 6 December 2015 through 9 December 2015 ; Volume 2016-March , 2016 , Pages 153-156 ; 9781509002467 (ISBN) Molaei, H ; Khorami, A ; Eslampanah Sendi, M. S ; Hajsadeghi, K ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc 
    A low power four bit mixed Successive Approximation Register (SAR)-Flash Analog to Digital Converter (ADC) for Sigma-Delta ADC applications is presented. The ADC uses three comparators in order to reduce the latency of typical SAR ADCs. Three comparators are used for conversion of 2 bits per one clock cycle. One of the Digital to Analog Converters (DACs) is replaced by three resistors which can save power and area. The ADC is simulated by Cadence Spectre using TSMC 0.18um COMS technology. The power consumption at 165MS/s and 1.8V supply voltage is 1.8mW. The SNDR and SFDR for 10MHz input are 19.8dB and 28.4dB, respectively  

    FPGA-based fault tolerant scheme with reduced extra-sensor number for WECS with DFIG

    , Article Proceedings - ISIE 2011: 2011 IEEE International Symposium on Industrial Electronics, 27 June 2011 through 30 June 2011 ; 2011 , Pages 1595-1601 ; 9781424493128 (ISBN) Shahbazi, M ; Gaillard, A ; Poure, P ; Zolghadri, M. R ; Sharif University of Technology
    Fast fault detection and converter reconfiguration is necessary for fault tolerant doubly fed induction generator (DFIG) in wind energy conversion systems (WECS) to prevent further damage and to make possible the continuity of service. Extra sensors are needed in order to detect the faults rapidly. In this paper, a very fast FPGA-based fault detection scheme is presented that minimizes the number of additional voltage sensors. A fault tolerant converter topology for this application is studied. Control and fault detection system are implemented on a single FPGA and Hardware in the Loop experiments are performed to evaluate the proposed detection scheme, the digital controller and the fault...