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    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... 

    Investigation of the effect of nanosilica on rheological, thermal, mechanical, structural, and piezoelectric properties of poly(vinylidene fluoride) nanofibers fabricated using an electrospinning technique

    , Article Industrial and Engineering Chemistry Research ; Volume 56, Issue 44 , 2017 , Pages 12596-12607 ; 08885885 (ISSN) Haddadi, S. A ; Ahmad Ramazani, S. A ; Talebi, S ; Fattahpour, S ; Hasany, M ; Sharif University of Technology
    The effects of different nano-SiO2 contents on the rheological properties of poly(vinylidene fluoride) (PVDF) solution and mechanical, thermal, structural, and piezoelectric properties of composite nanofibers were investigated. Results showed an increase in fiber diameter (∼125 to 350 nm) and ∼450% increase in tensile strength as the content of nano-SiO2 particles increased. The degree of crystallinity decreased by 19% as the nano-SiO2 content increased by 2% (w/w). Further investigation demonstrated that silica could significantly improve the piezoelectric properties of PVDF nanofibers as the output voltage showed an increase in the presence of silica attributed to change in the crystalline... 

    Axiomatic control of Buck converter for high efficiency over wide load range

    , Article 2008 IEEE International Conference on Industrial Technology, IEEE ICIT 2008, Chengdu, 21 April 2008 through 24 April 2008 ; 2008 ; 9781424417063 (ISBN) Kaboli, S ; Haddadi, A ; Khaligh, A ; Sharif University of Technology
    In this paper, the axiomatic design is introduced for controlling a power electronic converter. The main idea of axiomatic design is to introduce variables affecting the desired performances of the system most independently possible. The control process is presented for a Buck converter to achieve constant efficiency and output voltage ripple. ©2008 IEEE  

    A low-area, 0.18μm CMOS, 10Gb/s optical receiver analog front end

    , Article 2007 IEEE International Symposium on Circuits and Systems, ISCAS 2007, New Orleans, LA, 27 May 2007 through 30 May 2007 ; 2007 , Pages 3904-3907 ; 02714310 (ISSN) Maadani, M ; Atarodi, M ; Sharif University of Technology
    A fully integrated, low-cost (area), low-power, high-gain, differential Optical Receiver Analog Front-End (AFE), including Transimpedance Amplifier (TIA), Limiting Amplifier (LA), DC-Offset Cancellation Feedback and Output-Buffer is designed in TSMC 0.18μm CMOS Technology. The optimized TIA has a Regulated Cascode (RGC) topology, with 5.9mW power-dissipation, 48 dBΩ gain, 8.46GHz bandwidth. The Proposed Limiting Amplifier (LA) has an Inductor-Less topology, with 41.9dB gain, 91.1mW power consumption (including Output Buffer), output swing of 0.4VP-P, and bandwidth of 7.88GHz (Output-Buffer applied), using Built-in Active Inductors and Negative Miller Capacitance to broaden the bandwidth. The... 

    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) Eskandari, R ; Tarzamni, H ; Sabahi, M ; Khoun Jahan, H ; Mohammadsalehian, S ; Blaabjerg, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    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... 

    Operation and design analysis of an interleaved high step-up DC–DC converter with improved harnessing of magnetic energy

    , Article International Journal of Circuit Theory and Applications ; Volume 49, Issue 2 , 2021 , Pages 221-243 ; 00989886 (ISSN) Sabahi, M ; Tarzamni, H ; Kolahian, P ; Sharif University of Technology
    John Wiley and Sons Ltd  2021
    In this paper, a new interleaved DC–DC converter based on a coupled and a single input inductor is proposed. The suggested high step-up converter utilizes various inductive and capacitive methods to transfer magnetic energy more efficiently. The output voltage is regulated with the switches' duty cycle and the coupled inductor (CI) turns ratio, which provide a wide output voltage range. Interleaving improves the converter reliability, employs both the first and third areas of CI's B-H plane, cancels DC component of the CI, and reduces the input current ripple of the proposed converter with twice switching frequency. Utilization of two output ports for voltage stress and ripple reduction in... 

    Constant input power control of a three phase isolated buck+boost rectifier

    , Article INTELEC, International Telecommunications Energy Conference (Proceedings), 6 June 2010 through 10 June 2010, Orlando, FL ; June , 2010 ; 02750473 (ISSN) ; 9781424433841 (ISBN) Mohammadpour, A ; Zolghadri, M. R ; Ferdowsi, M ; Sharif University of Technology
    A novel control method is proposed for single-stage three-phase isolated buck+boost rectifier. The control method is based on the conventional cascade two-loop control structure and is modified to achieve constant instantaneous input power. Input voltages, output voltage, and DC-link inductor current are measured to control the power switches to achieve output voltage regulation as well as input power factor correction. In the proposed method, input currents are controlled such that input power is constant even for unbalanced mains. Thus for balanced mains converter behaves like an ideal rectifier, and for unbalanced mains, low-frequency harmonics of the output voltage are suppressed. The... 

    Multi-input high step-up inverter with softswitching capability, applicable in photovoltaic systems

    , Article IET Power Electronics ; Volume 13, Issue 1 , 2020 , Pages 133-143 Babaei, E ; Tarzamni, H ; Tahami, F ; Khoun Jahan, H ; Bannae Sharifian, M. B ; Sharif University of Technology
    Institution of Engineering and Technology  2020
    In this study, a new multi-input high step-up inverter, based on isolated soft-switching DC-DC converter blocks is proposed. Each of these blocks can provide zero-voltage and zero-current switching for its semiconductors, which improve power efficiency. The interesting feature of this DC-DC converter is using bidirectional switches to generate both positive and negative output voltage levels in each DC-DC block with an appropriate control scheme. Each DC-DC converter operates by simple pulse width modulation control through fixed frequency and has two degrees of freedom, which provide the capability of output voltage regulation or maximum power point tracking. The proposed inverter consists... 

    A lab-scale set up for thermal radiation experiments with cold junction compensation

    , Article Education for Chemical Engineers ; Volume 7, Issue 4 , 2012 , Pages e203-e209 ; 17497728 (ISSN) Foad Marashi, S. K ; Farhadi, F ; Fallahpour, N ; Sharif University of Technology
    The concepts of thermal radiation heat transfer are not tangible for many students. Experiments relied on various parameters can clarify the concepts of this mode of heat transfer.A lab-scale set up is described to study the thermal radiation heat transfer experiments. An electrical circuit of the thermopile sensor is designed and manufactured to provide experimental data.The validity of Inverse Square, Stefan-Boltzmann, and Kirchhoff Laws are investigated experimentally in the setup. Results indicate that, it is necessary to consider temperature shifts in the thermopile cold junction which is a potential source of error. Therefore, the output voltage, corresponding to the sensor... 

    Optimized design and implementation of low-cost, sensitive and versatile vibrating sample magnetometer

    , Article ICEE 2012 - 20th Iranian Conference on Electrical Engineering, 15 May 2012 through 17 May 2012 ; May , 2012 , Pages 202-205 ; 9781467311489 (ISBN) Hosseini, N ; Khiabani, S ; Sarreshtedari, F ; Fardmanesh, M ; Sharif University of Technology
    Geometry of different electromagnetic parts of Vibrating Sample Magnetometer (VSM) is a major factor of VSM output voltage. In this paper design, geometry optimization and implementation of a sensitive, versatile and relatively inexpensive VSM system has been described. Considering all effective geometrical parameters in the system output voltage, the induced voltage in the pick-up coils has been obtained analytically and the geometry of the pick-up coils has been optimized for maximum output induced voltage. Two opposite series of pick-up coils, piezoelectric based vibration system and required electronic circuits have been designed and the VSM system has been implemented. The implemented... 

    An MPC method based on a hybrid model of a three-phase inverter with output LC- filter

    , Article 2012 3rd Power Electronics and Drive Systems Technology, PEDSTC 2012, 15 February 2012 through 16 February 2012 ; February , 2012 , Pages 170-174 ; 9781467301114 (ISBN) Mazaheri, B ; Mokhtari, H ; Sharif University of Technology
    Controlling inverters with LC output filters in order to achieve a high quality desired output voltage or current is a challenging problem in power electronics. The LC filter and the binary nature of switch state variables increase the difficulty of achieving a single comprehensive model for the system. In this paper, a hybrid model is presented for a three-phase inverter with an LC output filter and a three-phase RL load. Then, the Model Predictive Control (MPC) algorithm is applied to the model and a geometrical approximate method is used to fit the answers to the binary values. Simulation results for a sample system verify the usability of the method and the quality of the answers  

    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) Khodabandeh, M ; Zolghadri, M. R ; Noroozi, N ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    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... 

    Space vector modulation for four-switch rectifier with compensating the effect of capacitors voltage ripple

    , Article 2009 International Conference on Electric Power and Energy Conversion Systems, EPECS 2009 ; 2009 ; 9789948427155 (ISBN) Ounie, S ; Zolghadri, M. R ; Sharif University of Technology
    A space vector modulation (SVM) approach is proposed to control a four-switch rectifier with power factor correction and compensating the effect of capacitors voltage ripple. The theory and performance of this method are presented, and the method effectiveness is demonstrated by extensive simulations. The simulation results show that the capacitor voltage ripple effects in the output voltage and current shaping can be omitted and the rectifier can work agreeably under high power factor condition although capacitors voltage is not balance. The allowable amount of this unbalanced value of filter capacitors is determined  

    Reducing output voltage THD of a three-phase inverter with non-linear load using disturbance observer

    , Article 8th Power Electronics, Drive Systems and Technologies Conference, PEDSTC 2017, 14 February 2017 through 16 February 2017 ; 2017 , Pages 431-436 ; 9781509057665 (ISBN) Valizade Alavi, S ; Tahami, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2017
    Non-linear loads such as rectifiers are growing in industry. Three phase inverter with non-linear load can lead to highly distorted output voltage. This paper proposes a method for reducing voltage THD in three phase inverters with non-linear load. The proposed method considers the load current as a disturbance and provide a control strategy to reject it using the disturbance observer method. This method doesn't need any additional sensors or hardware and is implemented digitally in controller. Simulation results show that the presented method will reduce the total harmonic distortion of the output voltage. © 2017 IEEE  

    Improvement of post-fault performance of a cascaded h-bridge multilevel inverter

    , Article IEEE Transactions on Industrial Electronics ; Volume 64, Issue 4 , 2017 , Pages 2779-2788 ; 02780046 (ISSN) Ouni, S ; Zolghadri, M. R ; Khodabandeh, M ; Shahbazi, M ; Rodríguez, J ; Oraee, H ; Lezana, P ; Schmeisser, A. U ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2017
    This paper is focused on improving the post-fault performance of cascaded H-bridge multilevel inverters by decreasing the common-mode voltage. First, an algorithm is proposed to determine the optimal post-fault state among all possible states, which have the same maximum available voltage. Furthermore, a modified technique is proposed to calculate the references of inverter phase voltages under faulty conditions. This technique leads to a decrease in the common-mode voltage when the required output voltage is less than its maximum value. These solutions are mutually employed in the post-fault control system. Simulation and experimental results confirm the effectiveness of the proposed... 

    Non isolated ZCT DC-DC converter for high step-up, high efficiency applications using resonant PWM technique

    , 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 398-403 ; 9781538646977 (ISBN) Sadeghpoor, D ; Habibagahi, I ; Zolghadri, M. R ; Atarodi, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    This paper presents a new topology for DC/DC converter which satisfies the need for high gain, high efficiency, low weight and low cost for renewables application. This topology is a novel approach of Resonant PWM converters which produces high output voltage with soft switching method (ZVS). The converter can be controlled both by PWM and frequency variation method. The main characteristics of this structure are illustrated using simulation results and compared with other well-known structures. © 2018 IEEE  

    An Extremely low ripple high voltage power supply for pulsed current applications

    , Article IEEE Transactions on Power Electronics ; Volume 35, Issue 8 , 2020 , Pages 7991-8001 Zarghani, M ; Mohsenzade, S ; Hadizade, A ; Kaboli, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    This article describes the development of an 18 kV, 30 kW power supply for a pulsed current load with the maximum current of 20 A and a di/dt equal to 100 A/μs. The achieved output ripple is less than 0.01%. In such a high level of precision, the most important issues are considerable difference between the instantaneous and average output powers, as well as insufficient reaction speed of the converter to the fast load change. Very low level of the voltage feedback and its sensitivity to the noise. The first issue necessitates a notable overdesign of the converter switches if the output voltage precision is dedicated to the converter. The second issue raises the problems relevant to... 

    A new high step-up interleaved LLC converter

    , Article 12th Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2021, 2 February 2021 through 4 February 2021 ; 2021 ; 9780738111971 (ISBN) Amani, D ; Beiranvand, R ; Zolghadri, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    In this study, a new LLC resonant converter for high-voltage high-power applications is introduced. The introduced power converter is a two-phase interleaved full-bridge based that uses a transformer with secondary and tertiary windings to obtain higher output voltage. Zero voltage switching (ZVS) at MOSFETs turn on and zero current switching (ZCS) for all the output diodes at turn off are achieved for a wide range of input voltage (100 V-200 V) and output power (200 W-1500 W) variations. Simulation results show a 95% peak efficiency. © 2021 IEEE  

    Optimizing the LLC-LC resonant converter topology for wide-output-voltage and wide-output-load applications

    , Article IEEE Transactions on Power Electronics ; Volume 26, Issue 11 , 2011 , Pages 3192-3204 ; 08858993 (ISSN) Beiranvand, R ; Zolghadri, M. R ; Rashidian, B ; Alavi, S. M. H ; Sharif University of Technology
    LLC-LC resonant converter is a suitable circuit topology to design switched-mode power supplies for wide-output-voltage and wide-output-load applications. In this paper, a design procedure is introduced to optimize this converter. Unlike soft switching techniques for pulse width modulated converters, which usually apply an active auxiliary circuit to reduce switching losses and EMI, in the proposed converter, not only such circuits are not used, but also all of the parasitic elements are merged to the converters main components. Zero-voltage switching (ZVS) operation is realized for all power devices under all operating conditions. Thus, this converter is a suitable choice for... 

    Input-output linearisation of a fourth-order input-affine system describing the evolution of a three-phase/switch/level (Vienna) rectifier

    , Article IET Power Electronics ; Volume 4, Issue 8 , 2011 , Pages 867-883 ; 17554535 (ISSN) Ansari, R ; Feyzi, M. R ; Akbari Hamed, K ; Sadati, N ; Yasaei, Y ; Ouni, S ; Sharif University of Technology
    This study presents an analytical approach for proper selection of output functions to be regulated for the Vienna rectifier such that the resultant closed-loop systems are minimum phase. Specifically, two different adaptive control methodologies based on the input-output linearisation are developed and categorised. In the first category, three output functions are introduced and imposed to be zero by using three dynamic feedback laws. On the basis of states to be regulated, four different cases are studied and it is shown that only one of these cases results in a one-dimensional zero dynamics with an asymptotically stable equilibrium point. In the second category, two output functions are...