Search for: power-supplies
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    Building energy modeling with OpenStudio : a practical guide for students

    , Book Brackney, Larry ; Parker, Andrew ; Macumber, Daniel
    Springer International Publishing AG  2018

    Analysis and Improvement of Output Voltage Ripple in High Voltage DC Power Supply

    , M.Sc. Thesis Sharif University of Technology Ziaoddini, Mojtaba (Author) ; Kaboli, Shahryar (Supervisor)
    The TWT is highly sensitive to the ripple amplitude of its power supply output voltage. If the amplitude of the output voltage's ripple exceeds a certain limit, the amplitude of the undesired harmonics in the power spectrum of the TWT is greatly increased. Increasing the amplitude of undesired harmonics in the TWT output power spectrum reduces the accuracy and performance of the TWT. Therefore, for optimum TWT performance, a low-ripple power supply is essential. Typically, a low-frequency rectifier or high-frequency switching structure is used to build a high-voltage DC power supply. In this thesis, the different structures of high voltage DC power supplies are studied. Next, by focusing on... 

    A low loss linear voltage regulator for high voltage dc power supplies based on adjustable inductors

    , Article 11th Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2020, 4 February 2020 through 6 February 2020 ; 2020 Osanlo, M ; Pouresmaeil, K ; Kaboli, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    High voltage power supplies are widely used in telecommunication systems. To better utilize these power supplies, voltage should be stabilized at a certain level. In this application, in case of changing voltage, the desired output parameters will change, such as RF output power quality. Various methods have been proposed to stabilize the voltage at acceptable levels. One of the most commonly used methods is use of switching regulators that are considered for high efficiency in comparison with linear regulators. But the use of these regulators also has problems. One of these problems is electromagnetic interference which is very important in telecommunication systems. Therefore, the need for... 

    10KV High Voltgage DC Power Supply by Diode Rectifier and Switching Regulator to Reduce Output Capacitor

    , M.Sc. Thesis Sharif University of Technology Jannati, Mohammad Kazem (Author) ; Kaboli, Shahriyar (Supervisor)
    High voltage dc power supplies are commonly used in medical equipment, microwave lamps, X-ray equipment and radio transmission systems. In radio Transmission power supplies the output voltage quality is of great importance and the output voltage ripple must be very low. In addition usage of low frequency transformer and rectifier needs large bulk capacitors to reduce output voltage ripple. Moreover, to reduce energy discharged into load in load short circuit faults the output capacitance should be as low as possible. An approach to solve this problem is to use a diode rectifier and a switching power supply in series configuration. The Advantage is that the switching power supply provides a... 

    Design and Analysis of a High Voltage Power Supply with Variable Output Voltage

    , M.Sc. Thesis Sharif University of Technology Khakparvar Yazdi, Amin (Author) ; Kaboli, Shahriyar (Supervisor)
    High voltage DC/DC converters are widely used in lasers, microwave tubes supplies, X-ray equipment, medical and industrial applications. Each of these applications have special attention to certain parameters such as output voltage ripple, fast stability, repeatability and accuracy. For power modulation in microwave tubes, the anode-cathode supply need to be varied. Generally such variations needs a high voltage DC supply so that, in a certain frequency each point can be controlled in specific voltage. Anode- cathode current flow is too low (in milliamps scale) so, the load of converter output can be assumed to be zero. The goal of this thesis is to design a DC/DC converter for Variable... 

    Design and Implement a High Voltage Switching DC Power Supply Based on Voltage Multiplier for High Regulation and Controllable Output Voltage

    , M.Sc. Thesis Sharif University of Technology Ahmadi, Abbas (Author) ; Kaboli, Shahriyar (Supervisor)
    High DC voltage is widely used in many applications such as X-Ray machines ,CRT , photocopy machines and etc. One idea to produce this high DC voltage is to use transformers, but it will be large in volume. We can increase frequency to reduce the volume of transformers but high voltage of primary and secondary winding will limited this volume reduction. Furthermore high turn ratio in transformers increases non idealities that cause voltage and current spike, and increase loss and noise. The main goal of this thesis is to reduce differential mode voltages on transformers to reduce the volume of power supply. Voltage multiplier will be used to reduce differential mode voltage. Voltage... 

    Design of Excitation Circuits for Cold Plasma Characterization Chamber

    , M.Sc. Thesis Sharif University of Technology Vardast, Sajjad (Author) ; Rashidian, Bijan (Supervisor)
    Plasma is a quasi-neutral gas consist of charged and neutral particles that manifest collective behavior. Plasma is an ionized gas in which all or a significant portion of its atoms have lost one or more electrons and become a set of positive ions and electrons. Plasma is one of the four primary states of matter. This project intends to generate plasma by a pulsed electric discharge in a gaseous environment. At first, in this project, the proper excitation circuits are collected and compared, then based on the feasibility of production, applicable methods are selected and constructed. The construction steps were such that the selected circuits were first simulated with the appropriate... 

    Design and Implement of Voltage Ripple Measuring System for Power Supply of Microwave Tubes

    , M.Sc. Thesis Sharif University of Technology Ahmadi Someh, Saeed (Author) ; Kaboli, Shahryar (Supervisor)
    Mostly, the high voltage DC power supplies have output voltage ripple. In such an applications like power supply of microwave lamps in radar systems, low output voltage ripple is an important point of operational characteristics. On the other hand, measuring the low voltage ripple will be a challenge that can lead to recognize of its reasons and reduce its amplitude. In this thesis, different ways of ripple measurement constraints is described, then a method based on high pass filters for output voltage ripple measurement is implemented. The impact of components tolerance and their parasitic components like shunt parasitic resistance of a capacitor in filter operational characteristics is... 

    A proportional-resonant controller-based wireless control strategy with a reduced number of sensors for parallel-operated UPSs

    , Article IEEE Transactions on Power Delivery ; Volume 25, Issue 1 , 2010 , Pages 468-478 ; 08858977 (ISSN) Hasanzadeh, A ; Caglar Onar, O ; Mokhtari, H ; Khaligh, A ; Sharif University of Technology
    In this paper, a novel droop method to control the power sharing of parallel uninterruptible-power-supply (UPS) systems is presented. In a clear-cut contrast to the previously reported works, the controller is a proportional-resonant controller which ensures good transient response and steady-state objectives. Furthermore, the need for sensing the output current for the power-sharing control is removed by implementing it in a software routine. This brings a less complicated and less expensive structure in which the number of feedback sensors is reduced from three to two. The droop paralleling strategy is based on the drop in the inverter output frequency and amplitude. The application of... 

    Robusting Series Structure of Semiconductor Switches for High Voltage Applications

    , Ph.D. Dissertation Sharif University of Technology Mohsenzadeh Hedesh, Sadegh (Author) ; Kaboli, Shahriyar (Supervisor)
    The series structure of semiconductor devices has a wide application in the industry and research field. The most critical issue in the series structure of series switches is the safe operating condition provision. Hence many kinds of research have been intensively focused on this topic to overcome this necessity. However, many existing aspects relevant to the series stacking of the semiconductor switches have not been pointed out. These include, the power loss must be accepted for the series devices and recovery of this power, providing balanced voltage for the series devices through a simple and easy implementing structure and providing a safe voltage condition for the series devices under... 

    Analysis of Energy of High Voltage Arcing in the Cathode of Microwave Vacuum Tubes

    , M.Sc. Thesis Sharif University of Technology Khazeinasab, Rashid (Author) ; kaboli, Shahriyar (Supervisor)
    In recent years, semiconductor devices have incrementally taken the place of microwave tubes beneficially. However, microwave tubes are still indispensable in very high voltage usages (10 Kilowatts to 10 Megawatts) and high frequencies (Gigahertz and higher). Concerning that these tubes are of the most sensitive and expensive parts of such systems, protection measures are of high importance. One of the phenomena that cause failure or degradation of tubes is electric arc in cathode of the tubes and dissipating energy due to that. In order to prevent the tubes from undergoing such harm, protection must be put into consideration. Furthermore, the limit of this dissipating energy determines the... 

    Analysis of Output Voltage Power Spectrum of High Voltage Power Supply

    , M.Sc. Thesis Sharif University of Technology Nouri Jevinani, Hadi (Author) ; Kaboli, Shahriyar (Supervisor)
    Some microwave tubes can function as a narrowband power amplifier and their output power spectrum is an indicator of their amplification and efficiency. One of the factors affecting its power spectrum is the noise and ripple of its HVDC power supply. To reduce the negative effects of power supply, first there should be an exact measurement of ripple and noise in the output of the HVDC power supply. Destructive factors which affect voltage ripple measurement in the case of high DC voltage are follows as conductive interference, radiative interference, intrinsic noise of electrical elements, and nonideal frequency response of voltage divider. After identifying and suppressing the mentioned... 

    Optimizing the normalized dead-time and maximum switching frequency of a wide-adjustable-range LLC resonant converter

    , Article IEEE Transactions on Power Electronics ; Volume 26, Issue 2 , August , 2011 , Pages 462-472 ; 08858993 (ISSN) Beiranvand, R ; Rashidian, B ; Zolghadri, M. R ; Alavi, S. M. H ; Sharif University of Technology
    LLC resonant converter has been widely used in dcdc converters. In this paper, optimum dead-time and maximum switching frequency of a wide-adjustable-range LLC resonant converter are investigated for realizing the zero voltage switching (ZVS) operation even under the worst-case conditions. Analyses demonstrate that these parameters depend on the converter inductance ratio and ratio of the converter resonant capacitor and the effective capacitance appeared in parallel with the drainsources of the power MOSFETs. The necessary dead time for realizing the ZVS operation can be minimized by choosing the normalized maximum switching frequency, properly. Using the dead-time optimum value, soft... 

    A series stacked IGBT switch based on a concentrated clamp mode snubber for pulsed power applications

    , Article IEEE Transactions on Power Electronics ; Volume 34, Issue 10 , 2019 , Pages 9573-9584 ; 08858993 (ISSN) Zarghani, M ; Mohsenzade, S ; Kaboli, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Clamp mode snubbers are very well suited for the series structure of the insulated-gate bipolar transistors (IGBTs) in pulsed power applications. They properly meet the necessities expected from them such as the fast operating of the series IGBTs since they have no effect on the gate side. In addition, they can provide safe voltage condition for the IGBTs in short circuit faults, which are very probable in pulsed applications. The clamp mode snubber can perform its voltage balancing task whenever the power capacity of the snubber can support the injected powers due to the voltage unbalancing factors. This paper initially introduces the main factors injecting power to the snubbers. Then, it... 

    Optimum design of planar transformer for LLC resonant converter using metaheuristic method

    , Article 45th Annual Conference of the IEEE Industrial Electronics Society, IECON 2019, 14 October 2019 through 17 October 2019 ; Volume 2019-October , 2019 , Pages 6621-6626 ; 9781728148786 (ISBN) Nazerian, E ; Tahami, F ; Sharif University of Technology
    IEEE Computer Society  2019
    Isolated, high-density DC-DC converters play a crucial role in the power supply unit of information technology industries. By virtue of high efficiency and high power density, LLC resonant converters-among the rest of DC-DC converters-are suitable candidates for this application. The magnetic structure of this converter, however, is a bulky, dissipative part, which has a considerable portion of power loss. Improvement in the size and efficiency of the LLC transformer will lead to an overall enhancement of power density and efficiency of the converter. Nevertheless, the optimization of planar transformers for the LLC converter has not been studied enough. This paper proposes a... 

    Design and analysis of an original powered foot clearance creator mechanism for walking in patients with spinal cord injury

    , Article Disability and Rehabilitation: Assistive Technology ; Volume 14, Issue 4 , 2019 , Pages 333-337 ; 17483107 (ISSN) Maleki, M ; Badri, S ; Shayestehepour, H ; Arazpour, M ; Farahmand, F ; Mousavi, M. E ; Abdolahi, E ; Farkhondeh, H ; Head, J. S ; Golchin, N ; Mardani, M. A ; Sharif University of Technology
    Taylor and Francis Ltd  2019
    Background: The aim of this study was to assess the performance of an original powered foot clearance creator (PFCC) mechanism worn in conjunction with an isocentric reciprocal gait orthosis (IRGO) and evaluate its effect on trunk compensatory movements and spatiotemporal parameters in nine healthy subjects. Method: A PFCC motorized mechanism was designed that incorporated twin sole plates, the movements of which enabled increased toe to floor clearance during swing phase. A prototype was constructed in combination with an IRGO, and hence was re-named as an IRGO-PFCC orthosis. The effects of IRGO-PFCC usage on the spatiotemporal parameters and trunk compensatory movements during walking were... 

    Leakage inductance calculation of the transformers with disordered windings

    , Article IEEE Transactions on Plasma Science ; Volume 47, Issue 4 , 2019 , Pages 1799-1807 ; 00933813 (ISSN) Mohsenzade, S ; Aghaei, M ; Kaboli, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    In switching power supplies, the transformer leakage inductance (TLI) is of considerable practical significance. Ordered winding is the certain assumption in previously reported works for the calculation of the TLI value. However, disordered windings are usually unavoidable in practice and their effect on the value of the TLI is considerable. The problem becomes more complex when the number of winding turns increases. In this paper, the effect of winding disorder on the TLI value is investigated. In disordered wrapping, the winding turns arrangement (WTA) of each produced transformer is different from the others. Thus, each produced transformer has an exclusive TLI value in a disordered... 

    A Marx-based generator with adjustable FWHM using a controllable magnetic switch

    , Article IEEE Transactions on Dielectrics and Electrical Insulation ; Volume 26, Issue 2 , 2019 , Pages 324-331 ; 10709878 (ISSN) Naghibi Nasab, J ; Hadizade, A ; Mohsenzade, S ; Zarghany, M ; Kaboli, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    The lack of turn-off ability makes the spark gap-based Marx generator uncontrollable in terminating the output pulse. In addition, there are some limitations for rise time and voltage gain improvements in the conventional critically-damped Marx design. In this paper, an efficient over-damped design of Marx circuit is proposed, which leads to a shorter rise time as well as a larger voltage gain. A chopping magnetic switch is employed to achieve the desired values of the fall time and full width at half maximum (FWHM). Moreover, adding a DC bias circuit to the magnetic switch provides the ability to adjust the pulse FWHM parameter. Therefore, an output pulse with a shorter rise time, larger... 

    A high-voltage series-stacked IGBT switch with active energy recovery feature for pulsed power applications

    , Article IEEE Transactions on Industrial Electronics ; Volume 67, Issue 5 , 2020 , Pages 3650-3661 Mohsenzade, S ; Zarghani, M ; Kaboli, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Applying series configuration of the insulated gate bipolar transistors (IGBTs) to the pulsed power supplies offers unique features such as compactness and long life time. In the high-voltage pulsed power supplies, a large number of the IGBTs are required to be serially connected. Hence, the safe operating condition provision for the series IGBTs is an important and crucial issue. The effect of the voltage unbalancing factors becomes remarkable when the number of switches in the series structure increases. There are passive and active methods to balance the voltage of the series IGBTs. In both of these methods, an amount of power must be dissipated to remove the effect of the voltage... 

    Feasibility Study and Conceptual Design of Solar Energy Source for Surface Train System

    , M.Sc. Thesis Sharif University of Technology Maleki, Sina (Author) ; Durali, Mohammad (Supervisor)
    Advancements in solar powered systems bring about the possibility for today’s transportation systems to be operated and driven by such a clean and renewable source of energy. The challenging point of this combination is to draw high power levels from such a low power density source of energy. As a result, employing an efficient power storage and management system becomes inventible. The subjects of this research are to design a grid connected system and evaluate its performance and feasibility in a real application (Tehran- Mehrshahr surface train – Tehran 5th Metro Line). The task includes sixteen pairs of DC transmission lines which are powered by CIGS solar module technology and four...