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  • 1.
    Majid, Abdul
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Analysis and EMI suppression of MHz frequency range switch mode power supplies2013Doctoral thesis, comprehensive summary (Other academic)
  • 2.
    Majid, Abdul
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Analysis and implementation of switch mode power supplies in MHz frequency region2012Licentiate thesis, comprehensive summary (Other academic)
  • 3.
    Majid, Abdul
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Kotte, Hari Babu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Saleem, Jawad
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Ambatipudi, Radhika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Haller, Stefan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    High Frequency Half-Bridge Converter using Multilayered Coreless PrintedCircuit Board Step-Down Power Transformer2011In: 8th International Conference on Power Electronics - ECCE Asia: "Green World with Power Electronics", ICPE 2011-ECCE Asia, IEEE conference proceedings, 2011, p. 1177-1181Conference paper (Refereed)
    Abstract [en]

    This paper introduces high frequencyhalf bridgeDC-DC converter, using multilayered coreless Printed Circuit Board (PCB) step down power transformer. The converter is simulated and then implemented on a PCB. Complementary Pulse Width Modulated (PWM) signals are generated to turn on high and low side Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) alternately by a micro-controller. The isolated gate drive signals are provided to the high side MOSFET by using high frequency coreless PCB isolation transformer. We tested the converter for switching frequency range of 2 to 3 MHz, and for maximum input voltage up-to 170 V. The maximum output power achieved is 40 W and the maximum energy efficiency is approximately 82 %. © 2011 IEEE.

  • 4.
    Majid, Abdul
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Saleem, Jawad
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Alam, Farhan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Analysis of radiated EMI for power converters switching in MHz frequency range2013In: Proceedings - 2013 9th IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives, SDEMPED 2013, IEEE conference proceedings, 2013, p. 428-432Conference paper (Refereed)
    Abstract [en]

    The higher switching frequency in combination with di/dt loops and dv/dt nodes in the power stages of high frequency power converters generates higher order harmonics which cause Electro Magnetic Interference (EMI). It is commonly perceived that high frequency converters are more vulnerable to radiated EMI, thus, it is very important to analyze the radiated emission of these converters. According to the author’s knowledge, the analysis of the radiated emission of power converters switching in the MHz frequency region has not been presented until now. Therefore, in this paper, the measurements, and analysis of the near field radiated emissions of these emerging power converters is presented. These measurements are beneficial in the early design stage of power converters. Both E-field and H-field and captured and analyzed for a half bridge converter switching at 3 MHz and at the output power level of 25 W. The effects of the magnetic and electric field emissions with the addition of a Y-capacitor and secondary side common mode choke are analyzed.

  • 5.
    Majid, Abdul
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Saleem, Jawad
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Alam, Farhan
    SEPS Technologies AB, Holmgatan 10, 851 70 Sundsvall, Sweden.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    EMI Suppression in High Frequency Half Bridge Converter2013In: Elektronika ir Elektrotechnika, ISSN 1392-1215, Vol. 19, no 9, p. 75-80Article in journal (Refereed)
    Abstract [en]

    Electromagnetic effects influence the design of power converters switching in MHz frequency region. In these converters, the high switching frequency in combination with sudden changes in current and voltage levels generate higher order harmonics which causes Electro Magnetic Interference (EMI). To study the effects of increased switching frequency on conducted EMI, the harmonics amplitudes are analyzed by increasing the switching frequency of a two wire input half bridge power converter from 1.32 MHz to 3 MHz. In order to suppress the Common Mode (CM) conducted EMI, different possibilities of connecting the Y- capacitor in a two wire universal input half bridge converter are discussed and the conducted EMI is measured and analyzed by connecting the Y- capacitor at different points. The line filters are designed, characterized and implemented in order to suppress conducted EMI. The effects of increased switching frequency on the line filter design are studied by analysing the EMI spectrum of both the converters. The analysis of results indicates that the filter size is reduced by increasing the switching frequency of the power converter. 

  • 6.
    Majid, Abdul
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Saleem, Jawad
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    EMI filter design for high frequency power converters2012In: 2012 11th International Conference on Environment and Electrical Engineering, EEEIC 2012: Conference Proceedings, IEEE conference proceedings, 2012, p. 586-589Conference paper (Refereed)
    Abstract [en]

    With the emerging power semiconductor devices in GaN and SiC technology and the development of high frequency multilayered PCB power transformers, power efficient DC-DC converters are designed in megahertz switching frequency range. The increased switching frequency in combination with sudden changes in current “di/dt” or voltage “dv/dt” levels generate higher order harmonics, which cause Electro Magnetic Interference (EMI). One of the major challenges, to design the power stage of these converters, is to minimize the EMI because it affects their Electro Magnetic Compatibility (EMC). There is a spread belief that the EMI becomes much worse in a MHz switching converter compared to the current ones operating below 150 kHz. This paper investigates the consequences on implementation of a line filter for suppressing conducted EMI in high frequency power converters. The results are based on electronic simulations, comparing EMI and filter design, for a 200 kHz and 2 MHz buck converter under similar conditions. By analyzing the noise frequency spectrum of both the converters it is observed that the size of filter components, such as capacitors and common mode chokes is greatly reduced in case of 2MHz Buck converter. The results show that the size reduction that can be accomplished by increasing the switching frequency to MHz range can be improved further by a smaller implementation of the line filter as well.

  • 7.
    Majid, Abdul
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Saleem, Jawad
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Kotte, Hari Babu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Ambatipudi, Radhika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Design and implementation of EMI filter for high frequency (MHz) power converters2012In: IEEE International Symposium on Electromagnetic Compatibility, IEEE conference proceedings, 2012, p. Art. no. 6396738-Conference paper (Refereed)
    Abstract [en]

    The fabrication of emerging power semiconductor devices and high frequency PCB power transformers has made it possible to design the power converters in MHz switching frequency range. However, the higher switching frequency, di/dt loops and dv/dt nodes in power stages of these converters generate higher order harmonics which causes Electro Magnetic Interference (EMI). It is commonly believed that the EMI has worst affect in the converters switching in MHz frequency range than the converters operating below 150 kHz. Thus, it is important research direction to investigate the consequences of implementing a line filter to suppress the conducted EMI in high frequency power converters. In this paper, the measurements, and analysis of the conducted EMI in emerging power converters, switching in MHz frequency range, and the design of the filter for its suppression is presented. The design of LISN and its PCB implementation for EMI measurements is presented. The measurement of conducted EMI of a half bridge DC-DC converter switching at          3.45 MHz and the analysis of the frequency spectrum is discussed. The design, PCB implementation and characterization of the EMI filter and the measurement of the suppressed conducted noise by applying the filter are also discussed.

  • 8.
    Majid, Abdul
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Saleem, Jawad
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Kotte, Hari Babu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Ambatipudi, Radhika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Haller, Stefan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Analysis of feedback in converter using coreless printed circuit board transformer2013In: Electrical Machines and Power Electronics and 2011 Electromotion Joint Conference (ACEMP), 2011 International Aegean Conference on, IEEE conference proceedings, 2013, p. 601-604Conference paper (Refereed)
    Abstract [en]

    Power supply is an inevitable component for all electronic instruments as a constant DC source. Almost all power supplies use feedback loop to achieve constant DC output voltage. In a feedback loop, the galvanic isolation is required between input and output. It can be achieved either by implementation of opto-coupler feedback on the secondary side or magnetic feedback. In this paper both opto-coupler and auxiliary feed-back techniques are implemented and analyzed in a high frequency half bridge converter using coreless Printed Circuit Board (PCB) power transformer. The implementation of opto-coupler feedback is temperature sensitive and has relatively high cost. The auxiliary winding of transformer can also be used to provide feedback signals as alternate to opto-coupler. Auxiliary feedback implementation is cheaper, temperature stable and insensitive to temperature variations. In this paper, the feasibility of feedback using auxiliary winding of coreless PCB power transformer is investigated. It is observed that this technique can be used as an alternative to opto-coupler feedback.

  • 9.
    Saleem, Jawad
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Majid, Abdul
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Ambatipudi, Radhika
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Kotte, Hari Babu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    High Frequency Full Bridge Converter using Multilayer Coreless Printed Circuit Board Step-up Power Transformer2011In: 2011 20th European Conference on Circuit Theory and Design, ECCTD 2011, IEEE conference proceedings, 2011, p. 805-808Conference paper (Refereed)
    Abstract [en]

    In designing switch mode power supply (SMPS), thedesirable feature is to have an efficient and compact design. Themain idea is to increase the switching frequency and reduce thebulky magnetic parts of the converter. This leads to a compactsize, less weight, reduced cost and increased power density of theconverter. This paper presents a high frequency full bridge DC toDC converter, using a multilayer coreless printed circuit board(PCB) step-up power transformer. The converter was simulatedand also implemented on the PCB. The pulse width modulated(PWM) signals were generated, using a microcontroller, to switchthe Metal oxide semiconductor field effect transistor (MOSFET).The design of the converter is tested up to the power levels of 5Watts with the switching frequency in 2 to 3MHz range. Theenergy efficiency of the converter is 74.86% at 2.4 MHz.

  • 10.
    Saleem, Jawad
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Majid, Abdul
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Carlberg, Torbjörn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    3 Dimensional Finite Element Simulation of Seam Welding Process2013In: Elektronika Ir Elektrotechnika, ISSN 1392-1215, Vol. 19, no 8, p. 73-78Article in journal (Refereed)
    Abstract [en]

    The versatility, rich mathematical formulations and robustness of finite element methods make them attractive for simulations for a wide range of problems. Two dimensional models concerning the seam welding process do have some limitations. The longitudinal two dimensional models cannot be used to examine the effects of the electrode shape and thickness regarding heat generation during the seam welding process. The transversal two dimensional models are not helpful for examining the nugget growth during the seam welding process. The heat energy generated during the seam welding process mainly depends on the resistance between the electrodes, welding current, rotational speed and the geometry of the electrodes. The settings for appropriate parameters in relation to a seam welding machine, with regards to sheets of different thicknesses, depends on trial and error methods. These methods are expensive and time consuming. The three dimensional model developed in this paper is a step towards selecting the appropriate welding parameters so as to produce a good welding nugget. 

  • 11.
    Saleem, Jawad
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Majid, Abdul
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Carlberg, Torbjörn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Spot welding Al 6082 Sheets with Preheating by Induction Heating ProcessManuscript (preprint) (Other academic)
  • 12.
    Saleem, Jawad
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Majid, Abdul
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Carlberg, Torbjörn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Nazar Ul Islam, Muhammad
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nugget Formation During Resistance Spot Welding Using Finite Element Model2012In: World Academy of Science, Engineering and Technology: An International Journal of Science, Engineering and Technology, ISSN 2010-376X, E-ISSN 2070-3740, Vol. 67Article in journal (Refereed)
    Abstract [en]

    Resistance spot welding process comprises of electric, thermal and mechanical phenomenon, which makes this process complex and highly non-linear and thus, it becomes difficult to model it. In order to obtain good weld nugget during spot welding, hit and trial welds are usually done which is very costly. Therefore the numerical simulation research has been conducted to understand the whole process. In this paper three different cases were analyzed by varying the tip contact area and it was observed that, with the variation of tip contact area the nugget formation at the faying surface is affected. The tip contact area of the welding electrode becomes large with long welding cycles. Therefore in order to maintain consistency of nugget formation during the welding process, the current compensation in control feedback is required. If the contact area of the welding electrode tip is reduced, a large amount of current flows through the faying surface, as a result of which sputtering occurs.

  • 13.
    Saleem, Jawad
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Majid, Abdul
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Schüberg, Linda
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Study the influence of the alignment and  nearby metallic objects on the Hall sensor system for current measurement in Resistance Spot Welding Machine2011In: 2011 10th International Conference on Environment and Electrical Engineering, EEEIC.EU 2011 - Conference Proceedings, IEEE conference proceedings, 2011, p. Art. no. 5874717-Conference paper (Refereed)
    Abstract [en]

    A technique for measuring the current of a stationaryspot welding unit using a Hall sensor system is implemented. HallEffect sensor is used to sense the strength of the magnetic fieldproduced by the current, flowing through the welding electrodes,on the secondary side of welding transformer. In contrast to acurrent transformer the Hall Effect sensor can read a DC currentand can thus be utilized in direct current welding equipments. Inthis paper the influence of the sensor position and presence of thetools or other materials in the proximity of the sensor that effectthe sensor reading is investigated. COMSOL Multiphysicssoftware is used to investigate these effects and a circuit design isimplemented according to the conclusion drawn from the simulations.

  • 14.
    Saleem, Jawad
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Majid, Abdul
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Haller, Stefan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Bertilsson, Kent
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    A study of IGBT rupture phenomenon in medium frequency resistance welding machine2013In: Electrical Machines and Power Electronics and 2011 Electromotion Joint Conference (ACEMP), 2011 International Aegean Conference on, IEEE conference proceedings, 2013, p. 236-239Conference paper (Refereed)
    Abstract [en]

    Inverter drive resistance spot welding machines are becoming a good choice of welding because of the increased machine efficiency and output power. The DC link capacitors in spot welding equipment store a large amount of energy. In case of any failure, the IGBT in the inverter has a risk of exhibiting a violent rupture. This rupture can damage the converter, drive down time and personal injury which may lead to the machinery certification problems. IGBT failure detection and solution for protection of these failures in resistance welding machines have not been reported in literature. Literature study of the IGBT failure, rupture, fault detection and protection has been carried out for inverter drives in power applications. On the basis of the findings some protection schemes and important measures in the design of the machine have been adopted which have resulted in the reduced risk of IGBT failure.

1 - 14 of 14
CiteExportLink to result list
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  • nn-NO
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  • asciidoc
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