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    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)
    Abstract
    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)
    Abstract
    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)
    Abstract
    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... 

    Analysis of the Effect of High-Power Microwave Tube Internal Fault on High Voltage Power Supply and Protection System

    , M.Sc. Thesis Sharif University of Technology Atharijoo, Esmaeel (Author) ; Kaboli, Shahriyar (Supervisor)
    Abstract
    RF amplifier are one of the most important part of communication industry. microwave 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 capacitor needed at the output of the power supply of the cathode. Since the value of the capacitor is directly proportionate to the amount of ripple of the output voltage, an exact calculation of... 

    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)
    Abstract
    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... 

    Applying of Data Fusion Method for Improving the Protection System of the High Voltage DC Power Supply

    , M.Sc. Thesis Sharif University of Technology Ayoubi, Ramin (Author) ; Kaboli, Shahriyar (Supervisor)
    Abstract
    Short-circuit fault detection is mandatory in a high voltage DC power supply to prevent fatal damage. The majority of converters employ a single sensor to detect the short-circuit fault. This attribute increases the interference vulnerability of the fault detection system in the presence of noise. Therefore, miss detections and false alarms are possible to occur. Miss detections and false alarms are harmful catastrophes in most applications. A commonly used method to suppress the noise impacts is using a low-bandwidth low-pass filter. However, the use of the low-bandwidth low-pass filter reduces the speed of fault detection due to the filter delay. This paper proposes a fast fault detection... 

    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)
    Abstract
    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... 

    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)
    Abstract
    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... 

    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
    Abstract
    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... 

    A voltage balancing method for series-connected igbts operating as a fault current limiter in high-voltage dc power supplies

    , Article IEEE Transactions on Industrial Electronics ; Volume 68, Issue 9 , 2021 , Pages 7895-7907 ; 02780046 (ISSN) Mohsenzade, S ; Zarghani, M ; Kaboli, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Abstract
    This article proposes a high-voltage fault current limiter (HVFCL) for high-voltage dc power supplies (HVdcPSs) which limits the current of the power supply automatically in the short-circuit fault (SCF). The proposed HVFCL is based on the series-connected insulated gate bipolar transistors (IGBTs). The main achievements of this article are the balanced voltage sharing and a very low value of the short-circuit current near to the load nominal current for the series-connected IGBTs during the SCF. These achievements result in a longer maximum permissible short-circuit time. These achievements are obtained by a control strategy that puts the series-connected IGBTs in a specific operating point... 

    A Multi-Output high voltage dc power supply with fast regenerative rectifier

    , Article 26th Iranian Conference on Electrical Engineering, ICEE 2018, 8 May 2018 through 10 May 2018 ; 2018 , Pages 1264-1268 ; 9781538649169 (ISBN) Naghibi Nasab, J ; Kaboli, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    A major problem in a multiple output converter structure is the different power flow via its various outputs. This problem leads to unwanted input DC-link voltage. This paper studies full bridge based DC-DC converters with multiple outputs. The effect of power flow variation is studied and a regenerative converter topology which controls the DC-link voltage by space voltage vector modulation technique is proposed. The proposed converter has a fast response to control the DC-link voltage in an acceptable band. Simulation and experimental results are presented to verify the analytical studies. © 2018 IEEE  

    A reopened crowbar protection for increasing the resiliency of the vacuum tube high-voltage DC power supply against the vacuum Arc

    , Article IEEE Transactions on Plasma Science ; Volume 47, Issue 5 , 2019 , Pages 2717-2725 ; 00933813 (ISSN) Pouresmaeil, K ; Kaboli, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    High-voltage power supplies (HVPSs) are widely used to supply vacuum tubes. The amount of delivered energy from the HVPS to the tube is an important issue during the vacuum arc in the tube. The conventional protection mechanism consists of a shunt crowbar which diverts the fault current from the tube to itself as a parallel path. The crowbar circuit is usually built of the devices without the turn-off capability. It is a drawback since the output of the power supply is shortened for a long time. Thus, the restoration time of these power supplies is excessive. This demerit can have detrimental effects on mission-critical applications. In this paper, the insulated-gate bipolar transistor... 

    A robust short-circuit fault diagnosis for high voltage DC power supply based on multisensor data fusion

    , Article 10th International Power Electronics, Drive Systems and Technologies Conference, PEDSTC 2019, 12 February 2019 through 14 February 2019 ; 2019 , Pages 659-664 ; 9781538692547 (ISBN) Ayoubi, R ; Kaboli, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    Short-circuit fault (SCF) detection is mandatory in a high voltage DC power supply (HVPS) to prevent fatal damage. The majority of converters employ a single sensor to detect the SCF. This attribute increases the interference vulnerability of the fault detection (FD) system in the presence of noise. Therefore, miss detections and false alarms are possible to occur. Miss detections and false alarms are harmful catastrophes in most applications. A commonly used method to suppress the noise impacts is using a low-bandwidth low-pass filter. However, the use of the low-bandwidth low-pass filter reduces the speed of FD due to the filter delay. This paper proposes a fast FD algorithm based on... 

    A Fast vacuum arc detection method based on the neural network data fusion algorithm for the high-voltage dc power supply of vacuum tubes

    , Article IEEE Transactions on Plasma Science ; 2020 Ayoubi, R ; Kaboli, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Abstract
    Vacuum arc is one of the most important failure factors of the vacuum tubes. The amount of delivered energy from the high-voltage dc power supply to the vacuum tube is an important issue during the vacuum arc in the tube. Vacuum arc acts as a short-circuit fault (SCF) at the power supply output. The majority of converters use a single current sensor to measure only the converter output current for detecting the SCF. However, the sensor may provide unreliable data because of the noise effect. Application of a low-pass filter reduces the noise effect. Regarding the delay of the low-pass filter, the interval of arc detection increases and more energy is delivered to the tube. In this article, a... 

    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 Pouresmaeil, K ; 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...