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  • 101.
    Antelius, Mikael
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Mikrosystemteknik.
    Fischer, Andreas
    KTH, Skolan för elektro- och systemteknik (EES), Mikrosystemteknik.
    Roxhed, Niclas
    KTH, Skolan för elektro- och systemteknik (EES), Mikrosystemteknik.
    Stemme, Göran
    KTH, Skolan för elektro- och systemteknik (EES), Mikrosystemteknik.
    Niklaus, Frank
    KTH, Skolan för elektro- och systemteknik (EES), Mikrosystemteknik.
    Room-temperature wafer-level vacuum sealing by compression of high-speed wire bonded gold bumps2011Ingår i: Proceedings IEEE International Conference on Solid-State Sensors, Actuators, and Microsystems (Transducers), IEEE , 2011, s. 1360-1363Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    This paper reports experimental results of a novel room temperature vacuum sealing process based on compressing wire bonded gold “bumps”, causing a material flow into the access ports of vacuum-cavities. The leak rate out of manufactured cavities was measured over 5 days and evaluated to less than the detection limit, 6×10-12 mbarL/s, per sealed port. The cavities have been sealed at a vacuum level below 10 mbar. The method enables sealing of vacuum cavities at room temperature using standard commercial tools and processes.

  • 102.
    Antelius, Mikael
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Gylfason, Kristinn B.
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Sohlström, Hans
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    An apodized surface grating coupler enabling single lithography silicon photonic nanowire sensors2012Konferensbidrag (Övrigt vetenskapligt)
  • 103.
    Antelius, Mikael
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Lapisa, Martin
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Niklaus, Frank
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Sohlström, Hans
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Holgado, Miguel
    Universidad Politécnica de Madrid.
    Casquel, Rafael
    Universidad Politécnica de Madrid.
    Sanza, Francisco J.
    Universidad Politécnica de Madrid.
    Griol, Amadeu
    Universidad Politécnica de Valencia.
    Bernier, Damien
    Multitel.
    Dortu, Fabian
    Multitel.
    Cáceres, Santiago
    ETRA I+D.
    Aparicio, Francisco J.
    Instituto de Ciencia de Materiales de Sevilla CSIC-Universidad de Sevilla.
    Alcaire, María
    Instituto de Ciencia de Materiales de Sevilla CSIC-Universidad de Sevilla.
    González-Elipe, Agustín R.
    Instituto de Ciencia de Materiales de Sevilla CSIC-Universidad de Sevilla.
    Barranco, Angel
    Instituto de Ciencia de Materiales de Sevilla CSIC-Universidad de Sevilla.
    A photonic dye-based sensing system on a chip produced at wafer scaleArtikel i tidskrift (Övrigt vetenskapligt)
  • 104.
    Antelius, Mikael
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Lapisa, Martin
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Niklaus, Frank
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Sohlström, Hans
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Holgado, Miguel
    Casquel, Rafael
    Sanza, Francisco J.
    Griol, Amadeu
    Bernier, Damien
    Dortu, Fabian
    Cáceres, Santiago
    Aparicio, Francisco J.
    Alcaire, Maria
    Gonzáles-Elipe, Agustin R.
    Barranco, Angel
    A wafer-scale, dye-based, photonic sensing systemManuskript (preprint) (Övrigt vetenskapligt)
  • 105.
    Antelius, Mikael
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Mikrosystemteknik.
    Stemme, Göran
    KTH, Skolan för elektro- och systemteknik (EES), Mikrosystemteknik.
    Niklaus, Frank
    KTH, Skolan för elektro- och systemteknik (EES), Mikrosystemteknik.
    Small footprint wafer-level vacuum packaging using compressible gold sealing rings2011Ingår i: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 21, nr 8, s. 085011-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel low-temperature wafer-level vacuum packaging process is presented. The process uses plastically deformed gold rings as sealing structures in combination with flux-free soldering to provide the bond force for a sealing wafer. This process enables the separation of the sealing and the bonding functions both spatially on the wafer and temporally in different process steps, which results in reduced areas for the sealing rings and prevents outgassing from the solder process in the cavity. This enables space savings and yields improvements. We show the experimental result of the hermetic sealing. The leak rate into the packages is determined, by measuring the package lid deformation over 10 months, to be lower than 3.5 x 10(-13) mbar l s(-1), which is suitable for most MEMS packages. The pressure inside the produced packages is measured to be lower than 10 mbar.

  • 106.
    Antonello, R.
    et al.
    University of Padova.
    Carraro, M.
    University of Padova.
    Peretti, L.
    ABB Corporate Research.
    Zigliotto, M.
    University of Padova.
    Hierarchical scaled–states direct predictive control of synchronous reluctance motor drives2016Ingår i: IEEE transactions on industrial electronics (1982. Print), ISSN 0278-0046, E-ISSN 1557-9948, Vol. 63, nr 8, s. 5176-5185Artikel i tidskrift (Refereegranskat)
  • 107.
    Antonello, R.
    et al.
    University of Padova.
    Peretti, L.
    ABB Corporate Research.
    Tinazzi, F.
    University of Padova.
    Zigliotto, M.
    University of Padova.
    Self-commissioning calculation of dynamic models for synchronous machines with magnetic saturation using flux as state variable2018Konferensbidrag (Refereegranskat)
  • 108.
    Antonello, Riccardo
    et al.
    University of Padova.
    Peretti, Luca
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Tinazzi, Fabio
    University of Padova.
    Zigliotto, Mauro
    University of Padova, Italy.
    Self-commissioning calculation of dynamic models for synchronous machines with magnetic saturation using flux as state variable2019Ingår i: The Journal of Engineering, ISSN 1872-3284, E-ISSN 2051-3305, nr 17, s. 3609-3613Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper deals with the non-linear modelling of synchronous machines by using the flux linkage as a state variable.The model is inferred from a conventional set of measurements where the relation between the currents and the flux linkages inthe rotating reference frame (also known as dq reference frame) are known by measurements or estimated through finite-element simulations. In particular, the contribution of this paper is twofold: first, it proposes a method to extract the non-linearmodel information which can be easily implemented in electric drives, without the need of offline post-processing of the data.Second, it mathematically demonstrates that the method converges to the final result in a stable way. An example based onexperimental measurements of the current-to-flux look-up tables of an 11-kW synchronous reluctance machine is shown,proving the feasibility of the proposed method.

  • 109.
    Antonopoulos, Antonios
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    On the Internal Dynamics and AC-Motor Drive Application of Modular Multilevel Converters2014Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Denna avhandling är ett försök att undersöka drift och egenskaper avmodulära multinivåomvandlare (M2C:er). Eftersom denna topologi anses varaden mest lovande inom högspänings-högeffekt-tillämpningar är, och somett underlag för att kunna formulera lämpliga styrmetoder, är det nödvändigtatt lägga kraft i att försöka förståde fysikaliska lagar som styr den inredynamiken i sådana omvandlare. Även om M2C:erna tillhör den välstuderadefamiljen av spänningsstyva omvandlare (VSC:er), och har en modulärstruktur, är deras reglering avsevärt mer komplicerad jämfört med två- ellertre-nivåomvandlare, eftersom ett mycket större antal switchar och kondensatorerär nödvändiga i en sådan topologi. Denna avhandling sätter fingretpå de parametrar som måste beaktas när man konstruerar regleringen för enM2C, genom att analysera den interna dynamiken, samt att föreslå sätt attstyra sådana omvandlare såatt stabil drift kan säkerställas utan att negativtpåverka prestanda.Ett speciellt fokus läggs på växelströmsmotordrifter eftersom de är särskiltutmanande vad gäller prestanda. Växelverkan mellan den interna dynamikenoch motorns dynamik undersöks experimentellt. Problemet att driva motornvid stillestånd behandlas även i fallet med hög ström och högt moment för atterhålla kunskap om kraven påomvandlaren i sådana fall. Slutligen föreslås enoptimering av omvandlarens drifttillstånd för att undvika överdimensioneringav omvandlarens komponenter i de fall detta är möjligt.Alla analytiska undersökningar som läggs fram i denna avhandling är bekräftadegenom experimentella resultat från en laboratorieomvandlare, somutvecklats inom ramen för detta arbete. Den experimentella verifieringen bevisargiltigheten av alla teoretiska undersökningar. Den visar också på demycket goda prestanda som de utvecklade styrmetoderna har vid drift aven verklig fysisk omvandlare. Förhoppningen är att resultaten från detta arbetekan komma till använding i storskaliga implementerinar i mega- ellergiga-wattklassen.

  • 110.
    Antonopoulos, Antonios
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Ängquist, Lennart
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Harnefors, Lennart
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Ilves, Kalle
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Stability Analysis of Modular Multilevel Converters With Open-Loop Control2013Ingår i: 39th Annual Conference of the IEEE Industrial Electronics Society, IECON 2013, IEEE , 2013, s. 6316-6321Konferensbidrag (Refereegranskat)
    Abstract [en]

    Modular multilevel converters (M2Cs) require that the controller is designed so that the submodule capacitor voltages are equalized and stable, independent of the loading conditions. Provided that the individual capacitor voltage sharing is managed effectively, an open-loop strategy can been designed to ensure that the total amount of energy stored inside the converter always will be controlled. This strategy, using the steady-state solutions of the dynamic equations for controlling the total stored energy in each converter arm, has proven to be effective. The intention of this paper is to explain in a rigorous way the mechanism behind the suggested strategy, and to prove that, when this open-loop strategy is used, the system becomes globally asymptotically stable.

  • 111.
    Antonopoulos, Antonios
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Ängquist, Lennart
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Harnefors, Lennart
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Optimal selection of the average capacitor voltage for modular multilevel converters2013Ingår i: 2013 IEEE Energy Conversion Congress and Exposition, ECCE 2013, IEEE , 2013, s. 3368-3374Konferensbidrag (Refereegranskat)
    Abstract [en]

    Variable-speed drives have reduced voltage requirements when operating below the base speed. In a modular-multilevel-converter-based (M2C-based) motor drive it is then possible to operate with reduced voltage in the submodule capacitors, than at the base speed. In this sense, a greater capacitor-voltage ripple can be accommodated, without exceeding the maximum peak-capacitor voltage. This paper presents an analytical investigation for the optimal selection of the average capacitor voltage for M2Cs, when the motor is operating with rated torque, below the base speed. This method does not require any power exchange between the converter arms, so it keeps the conduction losses at the minimum level. Additionally, the method decreases the switching losses, due to the decreased capacitor-voltage level. The overall ratings of the converter remain the same as in the base-speed operation. It is shown that this method can be applied at a speed range between the base speed and down to approximately one third of it, i.e, an operating range that covers the requirements for typical pump- and fan-type applications. The results obtained from the analytical investigation are experimentally verified on a down-scaled laboratory prototype M2C.

  • 112.
    Antonopoulos, Antonios
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Ängquist, Lennart
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Harnefors, Lennart
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Optimal Selection of the Average Capacitor Voltage for Variable-Speed Drives With Modular Multilevel Converters2015Ingår i: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107, Vol. 30, nr 1, s. 227-234Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Variable-speed drives have reduced voltage requirementswhen operating below the base speed. In a modularmultilevel-converter-based (M2C-based) motor drive it is thenpossible to operate with reduced voltage in the submodulecapacitors, than at the base speed. In this sense, a greatercapacitor-voltage ripple can be accommodated, without exceedingthe maximum peak-capacitor voltage. This paper presents ananalytical investigation for the optimal selection of the averagecapacitor voltage for M2Cs, when the motor is operating withrated torque, below the base speed. This method does not requireany power exchange between the converter arms, so it keepsthe conduction losses at the minimum level. Additionally, themethod decreases the switching losses, due to the decreasedcapacitor-voltage level. The overall ratings of the converterremain the same as in the base-speed operation. It is shownthat this method can be applied at a speed range betweenthe base speed and down to approximately one third of it,i.e, an operating range that covers the requirements for typicalpump- and fan-type applications. The results obtained from theanalytical investigation are experimentally verified on a downscaledlaboratory prototype M2C.

  • 113.
    Antonopoulos, Antonios
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Ängquist, Lennart
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Norrga, Staffan
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Ilves, Kalle
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Harnefors, Lennart
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Modular multilevel converter AC motor drives with constant torque from zero to nominal speed2014Ingår i: IEEE transactions on industry applications, ISSN 0093-9994, E-ISSN 1939-9367, Vol. 50, nr 3, s. 1982-1993Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Modular multilevel converters are shown to have a great potential in the area of medium-voltage drives. Low-distortion output quantities combined with low average switching frequencies for the semiconductor devices create an ideal combination for very high-efficiency drives. However, the large number of devices and capacitors that have to conduct the fundamental-frequency current require more complex converter control techniques than its two-level counterpart. Special care needs to be taken for starting and operation at low speeds, where the low-frequency current may cause significant unbalance between the submodule capacitor voltages and disturb the output waveforms. In this paper, principles for converter operation with high torque in the whole speed range are investigated. Experimental results from a down-scaled 12-kVA prototype converter running a loaded motor at various speeds between standstill and the rated speed are also provided.

  • 114.
    Antonopoulos, Antonios
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Ängquist, Lennart
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Norrga, Staffan
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Ilves, Kalle
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Modular multilevel converter ac motor drives with constant torque form zero to nominal speed2012Ingår i: 2012 IEEE Energy Conversion Congress and Exposition, ECCE 2012, IEEE , 2012, s. 739-746Konferensbidrag (Refereegranskat)
    Abstract [en]

    Modular multilevel converters (M2Cs) are shown to have a great potential in the area of medium-voltage drives. Low-distortion output quantities, combined with low average switching frequencies for the semiconductor devices create the ideal combination for very high-efficiency drives, both from an electric motor and an inverter point of view. With M2Cs the output voltage has such a low harmonic content that high-power motors can be operated without any derating. However, the large number of devices and the existence of capacitors that have to conduct the fundamental frequency current, requires more complex converter control techniques than its two-level counterpart. Special care needs to be taken under starting and operation with low frequency, where the low-frequency current may cause significant unbalance between the submodule capacitor voltages, disturb the output waveforms, and eventually cause the converter to trip. In this paper, principles for converter operation with high torque in the whole speed range, from standstill to rated speed will be investigated. The converter-control method utilizes estimation of the capacitor voltage variation, based on equations describing steady-state conditions. Experimental results from a down-scaled 12 kVA prototype converter running a loaded motor from zero up to the rated speed are provided in the paper.

  • 115.
    Appelgren, Patrik
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Experiments with and modelling of explosively driven mangetic flux compression generators2008Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis presents work performed on explosively driven magnetic flux compression generators. This kind of devices converts the chemically stored energy in a high explosive into electromagnetic energy in the form of a powerful current pulse. The high energy density of the high explosives makes flux compression generators attractive as compact power sources. In order to study these devices a generator was designed at FOI in the mid-90ies. Two generators remained unused and became available for this licentiate work.

    The thesis reports experiments with, and simulations of, the operation of the two remaining generators. The aim was to fully understand the performance of the generator design and be able to accurately simulate its behaviour. The generators were improved and fitted with various types of diagnostics to monitor the generator operation.

    Two experiments were performed of which the first generator was operated well below its current capability limits while the second was stressed far above its limits. Since the generator generates a rapidly increasing current, a current measurement is the most important diagnostic revealing the current amplification of the generator and its overall performance. Further it is important to measure the timing of various events in the generator. With a common time reference it is possible to combine data from different probes and extract interesting information which cannot be directly obtained with a single measurement.

    Two types of numerical simulations have been performed: Hydrodynamic simulations of the high explosive interaction with the armature were used to verify the measured armature dynamics. A zero-dimensional code was used to perform circuit simulations of the generator. The model takes into account the inductance reduction due to the compression of the generator as well as the change in conductivity due to heating of the conductors in the generators.

  • 116.
    Appelgren, Patrik
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Gigawatt pulsed power technologies and applications2011Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
  • 117.
    Appelgren, Patrik
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik. Swedish Defence Research Agency, Sweden .
    Andreasson, S.
    Hurtig, T.
    Larsson, A.
    Nyholm, S. E.
    Modelling of a small helical magnetic flux compression generator2007Ingår i: PPPS-2007 - Pulsed Power Plasma Science 2007, 2007, s. 1155-1158Konferensbidrag (Refereegranskat)
    Abstract [en]

    Helical flux-compression generators convert the chemical energy bond in explosives into electric energy. This paper briefly presents a model of, implemented in Matlab-Simulink, and simulation results for such a device. The simulation results are compared to experimental data from two experiments with identical generators but with different seed currents, influencing the resistive losses and thus the current amplification. The model is used to analyse the performance of the generator.

  • 118.
    Appelgren, Patrik
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Brenning, Nils
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Hurtig, Tomas
    Larsson, Anders
    Novac, Bucur
    Nyholm, Sten E.
    Modeling of a small helical magnetic flux compression generator2008Ingår i: IEEE Transactions on Plasma Science, ISSN 0093-3813, E-ISSN 1939-9375, Vol. 36, nr 5, s. 2662-2672Artikel i tidskrift (Refereegranskat)
    Abstract [en]

     In order to gain experience in explosive pulsed power and to provide experimental data as the basis for computer modeling, a small high-explosive-driven helical magnetic flux-compression generator (FCG) was designed at the Swedish Defence Research Agency. The generator, of which three have been built, has an overall length of 300 mm and a diameter of 70 mm. It could serve as the energy source in a pulse-forming network to generate high-power pulses for various loads. This paper presents a simulation model of this helical FCG. The model, which was implemented in Matlab-Simulink, uses analytical expressions for the generator inductance. The model of resistive losses takes into account the heating of the conductors and the diffusion of the magnetic field into the conductors. The simulation results are compared with experimental data from two experiments with identical generators but with different seed currents, influencing the resistive losses. The model is used to analyze the performance of the generator.

  • 119.
    Appelgren, Patrik
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Brenning, Nils
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Nyholm, Sten E.
    Small helical magnetic flux compression generators: experiments and analysis2008Ingår i: IEEE Transactions on Plasma Science, ISSN 0093-3813, E-ISSN 1939-9375, Vol. 36, nr 5, s. 2673-2683Artikel i tidskrift (Refereegranskat)
    Abstract [en]

     In order to gain experience in explosive pulsed power and to provide experimental data for modeling, a small high-explosive-driven helical magnetic flux-compression generator (FCG) was designed at the Swedish Defence Research Agency (FOI). The generator, of which three have been built, has an overall length of 300 mm and a diameter of 70 mm. It could serve as the energy source in a pulse-forming network to generate high power pulses for various loads. This paper presents the design of, and tests with, this helical FCG. The generator had an initial inductance of 23 mu H and was operated into a load of 0.2 mu H. The generator is charged with 0.27 kg of high explosives (PBXN-5). Various types of diagnostics were used to monitor the operation of the generator, including current probes, optical fibers, and piezo gauges. With seed currents of 5.7 and 11.2 kA, final currents of 269 and 436 kA were obtained, corresponding to current amplification factors of 47 and 39. The peak of the current was reached about 30 mu s after the time of crowbar. The two generators showed only small losses in terms of 2 pi-clocking. Using signals from optical fibers, the deflection angle of the armature could be determined to be 10 degrees in good agreement with hydrodynamic simulations of the detonation process and the detonation velocity to be 8.7 km/s in agreement with tabulated value.

  • 120.
    Appelgren, Patrik
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Larsson, Anders
    Nyholm, Sten E.
    Numerical simulations of flux compression generator systems2007Ingår i: Proceedings of the 20th IET Pulsed Power Symposium, 2007, s. 123-127Konferensbidrag (Övrigt vetenskapligt)
  • 121.
    Ariza, David
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Becerra, Marley
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Hollertz, R.
    Pitois, Claire
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Measurements of the charge of streamers propagating along transformer oil-solid interfaces2014Ingår i: Proceedings of the 2014 IEEE 18th International Conference on Dielectric Liquids, ICDL 2014, IEEE , 2014, s. 6893165-Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents an experimental study of the positive streamer charge in transformer oil and oil-solid interfaces in a point-plane gap (5mm) under impulse voltage 50ns\1800μs (maximum peak voltage 24 kV). The experiment is intended to compare the charge of streamers propagating in transformer oil with and without a solid barrier along their path. The solid barrier constricting the streamer volume consists of two parallel strips of either impregnated pressboard or a polymeric film (PA6) installed at both sides of the point electrode. The maximum cumulative charge of the streamer is found for the case when the impregnated pressboard is used and the minimum cumulative charge for the case of the polymer as a barrier.

  • 122.
    Armendariz, Mikel
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Industriella informations- och styrsystem.
    Brodén, Daniel
    KTH, Skolan för elektro- och systemteknik (EES), Industriella informations- och styrsystem.
    Honeth, Nicholas
    KTH, Skolan för elektro- och systemteknik (EES), Industriella informations- och styrsystem.
    Nordström, Lars
    KTH, Skolan för elektro- och systemteknik (EES), Industriella informations- och styrsystem.
    A Method to Identify Exposed Nodes in Low Voltage Distribution Grids with High PV Penetration2015Ingår i: IEEE Power and Energy Society General Meeting 2015, Denver, CO. July 26-30, 2015. / [ed] IEEE, IEEE Press, 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    The impact of introducing distributed energyresources at the low voltage side of the distribution grid iscurrently raising new challenges for utilities. In particular, thehigh penetration of photovoltaic panels (PVs) in radial grids isincreasing the active power losses in the branches and thevoltage level at some of the nodes. Principally nodes next to PVarray installations. This paper presents a methodology based ondesign of experiments (DOE) to detect such exposed nodes andbranches, together with the identification of the main scenariosthat cause such problems, characterized by: season, type of day,solar radiation and outdoor temperature levels. Themethodology is simulated on a LV network based on the Cigrebenchmark Grid with real utility data. The exposed nodes areclassified for each feeder from most to least problematic andshowed (as expected) sensitivity to seasonality (summertime),characterized by high solar radiation and outdoor temperatures.

  • 123.
    Armendariz, Mikel
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Industriella informations- och styrsystem.
    Chenine, Moustafa
    KTH, Skolan för elektro- och systemteknik (EES), Industriella informations- och styrsystem.
    Nordström, Lars
    KTH, Skolan för elektro- och systemteknik (EES), Industriella informations- och styrsystem.
    Al-Hammouri, Ahmad
    Jordan University of Science and Technology.
    A co-simulation platform for medium/low voltage monitoring and control applications2014Ingår i: 2014 IEEE PES Innovative Smart Grid Technologies Conference, ISGT 2014, IEEE conference proceedings, 2014, s. 6816369-Konferensbidrag (Refereegranskat)
    Abstract [en]

    The increasing demand for electricity and the penetration of renewable energy resources into the electrical grid are triggering the electric power system to undergo changes and complex modifications at high, medium and low voltage levels. There are large and complex projects such as Smart Grid Gotland to deploy solutions to address such challenges. However, there are several scenarios that could be more practical to be first studied via simulations. As such, the purpose of this paper is to propose and develop a co-simulation platform that allows performing real-time monitoring and control tests and simulations for MV/LV grids. This platform combines both electrical, and information and communication technology (ICT) infrastructure simulations. It consists of a real-time power system simulator (Opal-RT) connected to a communication network simulator (OPNET) through an automatic meter reading interface that is based on commercial off-the-shelf (COTS) and low cost devices such as Raspberry Pi and Arduino boards. The platform allows the analysis of realistic MV/LV grids and communication networks, and will facilitate the simulation and comparison of low voltage control strategies for real-time test scenarios that could be more complicated to test otherwise in real-life due to cost and complexity aspects , i.e., high power losses on the low voltage grid.

  • 124.
    Armendariz, Mikel
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Industriella informations- och styrsystem.
    Saleem, Arshad
    KTH, Skolan för elektro- och systemteknik (EES), Industriella informations- och styrsystem.
    Nordström, Lars
    KTH, Skolan för elektro- och systemteknik (EES), Industriella informations- och styrsystem.
    Brugeron, Mathieu
    Grenoble INP.
    Facilitating Distribution Grid Network Simulation Through Automated Common Information Model Data Conversion2015Ingår i: IEEE PowerTech Conference 2015, Eindhoven (Netherlands), 29 June - 2 July 2015 / [ed] IEEE, IEEE , 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    In R&D projects as well as in development work,simulations of grid configurations and control methods are acommon tool for assessing different technical options. At thesame time, these simulations are often limited by difficulties indata exchange, simply due to the fact that systems are notcompatible and data format in operational systems is not alignedwith data in simulation and analysis tools. To this extent a toolhas been developed that allows large scale import of real-worldgrid data using CIM XML to state of the art simulation toolsbased on MATLAB. The tool is used in a large FP7 projectinvolving leading European DSOs.

  • 125.
    Armengaud, Eric
    et al.
    Virtual Vehicle Competence Center, Austria.
    Zoier, Markus
    Virtual Vehicle Competence Center, Austria.
    Baumgart, Andreas
    OFFIS E. V., Germany.
    Biehl, Matthias
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Mekatronik.
    Chen, De Jiu
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Inbyggda styrsystem.
    Griessnig, Gerhard
    AVL List GmbH, Austria; Graz University of Technology, Austria.
    Hein, Christian
    Fraunhofer FOKUS, Germany.
    Ritter, Tom
    Fraunhofer FOKUS, Germany.
    Tavakoli-Kolagari, Ramin
    Volvo Technology Corporation, Sweden.
    Model-based Toolchain for the Efficient Development of Safety-Relevant Automotive Embedded Systems2011Ingår i: SAE Technical Paper: Paper Number: 2011-01-0056, Society of Automotive Engineers, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Advanced functionalities unthinkable a few decades ago are now being introduced into automotive vehicles through embedded systems for reasons like emission control, vehicle connectivity, safety and cooperative behaviors. As the development often involves stakeholders from different engineering disciplines and organizations, the complexity due to shared requirements, interdependencies of data, functions, and resources, as well as tight constraints in regards to timing, safety, and resource efficiency makes the system integration, quality control and assurance, reuse and change management increasingly more difficult. This calls for a more rigorous approach to the development of automotive embedded systems and components. This paper describes the CESAR reference technology platform (RTP) that supports the formalization of various engineering concerns in the development of safety-relevant embedded systems and thereby a model-based integration of various tools and methods to form seamless environments or toolchains for the development of such systems.

  • 126.
    Asadollahi, Ali
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik. KTH.
    A Study of Surface Treatments and Voids Formation in Low Temperature Wafer BondingManuskript (preprint) (Övrigt vetenskapligt)
  • 127.
    Asadollahi, Ali
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar. KTH.
    Compressive-Strained Ge and Tensile-Strained SiGe on Insulator Fabrication via Wafer Bonding for Monolithic 3D IntegrationManuskript (preprint) (Övrigt vetenskapligt)
  • 128.
    Asadollahi, Ali
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar. KTH.
    Low Temperature SiGe Epitaxy Using SiH4-GeH4and Si2H6-Ge2H6 Gas PrecursorsIngår i: Journal of Solid State Science and TechnologyArtikel i tidskrift (Övrigt vetenskapligt)
  • 129.
    Asiatici, Mikhail
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik. The School of Computer and Communication Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
    Laakso, Miku
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Fischer, Andreas
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik. The Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), 76344 Karlsruhe, Germany.
    Stemme, Göran
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Niklaus, Frank
    Through Silicon Vias With Invar Metal Conductor for High-Temperature Applications2017Ingår i: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 26, nr 1, s. 158-168Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Through silicon vias (TSVs) are key enablers of 3-D integration technologies which, by vertically stacking andinterconnecting multiple chips, achieve higher performances,lower power, and a smaller footprint. Copper is the mostcommonly used conductor to fill TSVs; however, copper hasa high thermal expansion mismatch in relation to the siliconsubstrate. This mismatch results in a large accumulation ofthermomechanical stress when TSVs are exposed to high temperaturesand/or temperature cycles, potentially resulting in devicefailure. In this paper, we demonstrate 300 μm long, 7:1 aspectratio TSVs with Invar as a conductive material. The entireTSV structure can withstand at least 100 thermal cycles from −50 °C to 190 °C and at least 1 h at 365 °C, limited bythe experimental setup. This is possible thanks to matchingcoefficients of thermal expansion of the Invar via conductor andof silicon substrate. This results in thermomechanical stressesthat are one order of magnitude smaller compared to copperTSV structures with identical geometries, according to finiteelement modeling. Our TSV structures are thus a promisingapproach enabling 2.5-D and 3-D integration platforms for hightemperatureand harsh-environment applications.

  • 130.
    Aslam, Bilal
    et al.
    Univ Engn & Technol, Dept Telecommun Engn, ACTSENA Res Grp, Taxila, Punjab, Pakistan..
    Azam, Muhammad A.
    Univ Engn & Technol, Dept Telecommun Engn, ACTSENA Res Grp, Taxila, Punjab, Pakistan..
    Amin, Yasar
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK. KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik. Univ Engn & Technol, Dept Telecommun Engn, ACTSENA Res Grp, Taxila, Punjab, Pakistan..
    Loo, Jonathan
    Middlesex Univ, Sch Engn & Informat Sci, Dept Comp Sci, London, England..
    Tenhunen, Hannu
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik, Integrerade komponenter och kretsar.
    A high capacity tunable retransmission type frequency coded chipless radio frequency identification system2019Ingår i: International Journal of RF and Microwave Computer-Aided Engineering, ISSN 1096-4290, E-ISSN 1099-047X, Vol. 29, nr 9, artikel-id e21855Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article presents a 12-bit frequency coded chipless RFID system in the frequency range of 3 to 6 GHz. The system consists of a fully printable chipless tag and a pair of high-gain reader antennas. The tag also incorporates its own antennas to improve the read range. Information is encoded into frequency spectrum using a multi-resonant circuit. The circuit consists of multiple microstrip U and L-shaped open stub resonators patterned in a unique configuration. The proposed configuration aids in capturing more data in a reduced space as well as tunable frequency operation. Tag and reader antennas utilize techniques such as stepped impedance feeding line, defective partial ground plane, and stair-step patch structure to achieve wide-band impedance bandwidth in miniature size. The results of the wireless measurements in the non-anechoic environment show that the proposed system has a reading range of more than 20 cm. The presented system possesses great potential for low-cost short-range inventory tracking.

  • 131.
    Aslam, Bilal
    et al.
    Univ Engn & Technol, Dept Telecommun Engn, ACTSENA Res Grp, Taxila 47050, Punjab, Pakistan..
    Kashif, Muhammad
    Univ Engn & Technol, Dept Telecommun Engn, ACTSENA Res Grp, Taxila 47050, Punjab, Pakistan.;Beijing Univ Aeronaut & Astronaut, Beijing, Peoples R China..
    Azam, Muhammad Awais
    Univ Engn & Technol, Dept Telecommun Engn, ACTSENA Res Grp, Taxila 47050, Punjab, Pakistan..
    Amin, Yasar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik. Univ Engn & Technol, Dept Telecommun Engn, ACTSENA Res Grp, Taxila 47050, Punjab, Pakistan.
    Loo, Jonathan
    Univ West London, Sch Comp & Commun Engn, Dept Comp Sci, London, England..
    Tenhunen, Hannu
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik. Univ Turku, Dept Informat Technol, TUCS, Turku, Finland..
    A low profile miniature RFID tag antenna dedicated to IoT applications2019Ingår i: Electromagnetics, ISSN 0272-6343, E-ISSN 1532-527X, Vol. 39, nr 6, s. 393-406Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    RFID tag antennas with stable performance on the diverse electromagnetic mounting platforms are an integral part of the ubiquitous RFID systems. This research article presents a novel tag antenna design that facilitates the said objective. The proposed antenna consists of a modified H-shaped slot structure that ensures considerable robustness from the application environment through confining the surface current density within the antenna structure. The antenna offers a tunable bandwidth of 40 MHz within the microwave band of (2.4-2.5) GHz. The proposed tag antenna exhibits excellent response on metallic platforms of different sizes and thicknesses with an effective gain of almost four times of that in free space. Furthermore, the designed tag antenna performs adequately well on low-medium permittivity dielectrics (glass, paper, and plastic) and RF absorbers (water). The free space and on-metal performance of the proposed tag antenna are verified by testing a prototype realized on the FR4 substrate.

  • 132.
    Atallah, Jad G.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektronik- och datorsystem, ECS.
    Integrated Frequency Synthesis for Convergent Wireless Solutions2008Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Wireless transceivers combining several standards in one unit are of key importance. In order to reach the ultimate goal of maximizing the performance-to-cost ratio of such modules, a careful study of the target application, the architecture, and the frequency planning is strongly required. One of the most challenging tasks is the implementation of the frequency synthesizer. This challenge is compounded by the traditional technical difficulties in designing frequency synthesizers as well as the new requirements that include multi-standard support. As a result, studying the upper levels of the communication system becomes mandatory in order to frame the requirements of the frequency synthesizer and to provide a viable solution from a user’s perspective for an always-best-connected scenario. Additionally, the study of the upper layers opens up new opportunities for innovation at the lower layers, especially at the physical layer where the view is traditionally restricted by some harsh requirements whose source might not be clear at least for the physical-level designer. The first aim of this work is to provide a holistic view of how an optimum user experience can be achieved and how this affects the design of frequency synthesizers for the next generation networks. The work is heavily based on the existing garden of wireless standards although it can also serve for other applications such as real software-defined radios and dynamic spectrum allocation. As a result, this work cuts a vertical path starting from the best user experience vision down to the physical layer where it expands on the design of the frequency synthesizer. It proposes a wireless front-end solution that can make the vision of an always-best-connected scenario a reality. The architecture is based on a wireless detector called Sniffer that searches for an alternative connection while the main connection is running. Not only is the Sniffer solution viable at the physical level, but it also provides a stepping stone for development towards fully-enabled multi-standard transceivers. After this, and inline with the previous vision, some important frequency synthesizer parameters are pointed out and enhancements on the phase-locked architectures are presented. This includes ways to extend the range of the frequency synthesizer and ways to make the synthesizer adaptable depending on the requirements of the wireless standards. This work leads directly to the implementation of a multi-standard frequency synthesizer where the details of the top-down design procedure are presented at several levels of abstraction. In order to round-up the work, and due to the fact that the requirements of the frequency synthesizer stretch thin the capabilities of the technology used, calibration techniques to increase the yield of such a complicated sub-system are presented, an important step towards first-pass success.

  • 133.
    Aurensanz, Alberto
    KTH, Skolan för elektro- och systemteknik (EES), Kommunikationsnät.
    A reliable transmission protocol fordistributed extraction of visual featuresusing BRISK and SURF2014Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Performing visual feature extraction in a network of processing

    nodes is challenging and requires the development of algorithms

    that perform the allocation and delegation of computational tasks,

    of protocols responsible for the correct transmission of data, etc.

    This report starts working from the implementation of a testbed

    for the evaluation of distributed processing of visual features and

    extends its functionality. The testbed is implemented in C++ us-

    ing credit-card sized computers and ZigBee USB units. Communi-

    cation between nodes is carried out through ASN.1 defined types.

    The first part of the thesis work consists of enabling the system

    to work with two different feature extraction schemes. The first

    one is the already implemented SURF algorithm from OpenCV

    and the second one is the original implementation of BRISK. The

    user must be capable of choosing indifferently between them. The

    second part of the work consists of modifying the transmission

    aspects of the system including the necessary classes to provide

    reliability via the design of a retransmission protocol. The reliable

    transmission protocol used is a version of a Stop-and-Wait scheme.

    The system’s performance is evaluated detailing the time needed

    to complete each step of the feature extraction process, presenting

    a comparison between the SURF and BRISK detection and ex-

    traction times, and computing the frame loss rate and achievable

    throughput once the retransmission protocol is implemented.

  • 134. Austrin, L.
    et al.
    Krah, Julius Hartwig
    KTH, Tidigare Institutioner, Elektrotekniska system.
    Engdahl, Göran
    KTH, Tidigare Institutioner, Elektrotekniska system.
    A modeling approach of a magnetic amplifier2004Ingår i: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, E-ISSN 1873-4766, Vol. 272, s. E1709-E1710Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    New soft magnetic materials made possible the use of the magnetic amplifier technology in designing competitive electric power supplies. This technology is used in the Swedish. fighter aircraft Gripen, being also attractive for future more electrical aircraft systems due to the possibility to achieve a compact and robust design. A modeling approach of a magnetic amplifier based on the magnetic hysteresis of the core material is presented here for a common amorphous magnetic alloy.

  • 135.
    Austrin, Lars
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    On magnetic amplifiers in aircraft applications2007Licentiatavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    In the process of designing an electric power supply system for an aircraft, parameters like low weight and low losses are important. Reliability, robustness and low cost are other important factors. In the Saab Gripen aircraft, the design of the primary power supply of the electric flight control system was updated by exchanging a switching transistor regulator to a magnetic amplifier (magamp). By introducing a magamp design, weight was saved and a more reliable power supply system at a lower cost was achieved.

    In this particular case, with the power supply of the electric flight control system in the Saab Gripen fighter, advantage could be taken of a specific permanent magnet generator (PM-generator). The frequency of the generator offered the perfect conditions for a magamp controller. A key parameter in designing magnetic amplifiers (magamps) is low losses. New amorphous alloys offer new possibilities of the technique in designing magnetic amplifiers, because of their extremely low losses.

    The core losses are evaluated by studying the equations and diagrams specifying the power losses. The core losses are evaluated and compared with the copper losses in the process of optimizing low weight and low losses. For this an engineering tool is developed and demonstrated.

    Evaluations of the hysteresis characteristics for the magnetic alloys, as well as modeling and simulation of the core losses, are presented in this work. The modeling of the core losses includes hysteresis losses, eddy current losses and excess losses as well as copper losses. The losses are studied dynamically during realistic operational conditions. The model can be used for any generic analysis of hysteresis in magnetic circuits. Applications of magnetic amplifiers in aircrafts have been demonstrated to be a feasible alternative

  • 136. Austrin, Lars
    et al.
    Engdahl, Göran
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Modeling of a Three-phase Magnetic Amplifier2004Ingår i: Proceedings of the 24th Congress of the International Council of the Aeronatical Science, Yokohama, Japan, 2004Konferensbidrag (Refereegranskat)
  • 137. Austrin, Lars
    et al.
    Krah, Julius
    KTH, Tidigare Institutioner, Elektrotekniska system.
    Engdahl, Göran
    KTH, Tidigare Institutioner, Elektrotekniska system.
    A Modeling Approach of a Magnetic Amplifier2003Ingår i: Proc. on ICM 2003 International Conference on Magnetism, Rome, Italy, 2003Konferensbidrag (Refereegranskat)
  • 138. Austrin, Lars
    et al.
    Torabzadeh-Tari, Mohsen
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Engdahl, Göran
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    A new high power density generation system2006Ingår i: ICAS-Secretariat, 25th Congress of the International Council of the Aeronautical Sciences 2006, 2006, s. 3600-3604Konferensbidrag (Refereegranskat)
    Abstract [en]

    A trend of increased Electric Power in Aircraft stresses the need of robust, low weight systems with low losses. New hard and soft magnetic materials have made it feasible to work with high speed and high frequency. Applications of new soft magnetic materials and hard magnetic materials like NeFeB magnets have enabled high density power generation systems. A new concept comprising a high speed PM-generator system and a magnetic amplifier control is presented. Magnetic amplifiers are used in the power supply of the Electronic Flight Control System in the Swedish "Gripen" fighter-aircraft. This technology is attractive in More Electric Aircraft (MEA) systems due to the possibility to achieve a compact, robust and a highly reliable system with low losses. Applications of new soft magnetic materials, such as amorphous magnetic alloys, have enabled the use of magnetic amplifier (magamp) technology in the design of competitive electric power converters. This paper presents a studied design on a 20-40 kW generator system including a +/- 270V controlled output, performed by magnetic amplifier technology. This work addresses the power generator, and the power converter. High speed PM-generators are offering high power density. The impact of operating a generation system with higher frequency and an increasing number of poles as well as the advantages with new soft magnetic materials is studied. The iron losses and the copper losses are analyzed for the generator, and the power converter.

  • 139. Autrin, Lars
    et al.
    Ribbenfjärd, David
    Engdahl, Göran
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Simulation of a mangietc amplifier circuit including hysteresis2005Ingår i: Intermag Asia 2005, 2005, s. 225-226Konferensbidrag (Refereegranskat)
  • 140.
    Avula, Ramana Reddy
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Teknisk informationsvetenskap.
    Oechtering, Tobias J.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Teknisk informationsvetenskap.
    Chin, Jun-Xing
    Power Systems Laboratory, ETH Zurich, Switzerland.
    Hug, Gabriela
    Power Systems Laboratory, ETH Zurich, Switzerland.
    Smart Meter Privacy Control Strategy Including Energy Storage Degradation2019Ingår i: 2019 IEEE Milan PowerTech, IEEE, 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we present a degradation-aware privacy control strategy for smart meters by taking into account the capacity fade and energy loss of the battery, which has not been included previously. The energy management strategy is designed by minimizing the weighted sum of both privacy loss and total energy storage losses, where the weightage is set using a trade-off parameter. The privacy loss is measured in terms of Bayesian risk of an unauthorized hypothesis test. By making first-order Markov assumptions, the stochastic parameters of energy loss and capacity fade of the energy storage system are modelled using degradation maps. Using household power consumption data from the ECO dataset, the proposed control strategy is numerically evaluated for different trade-off parameters. Results show that, by including the degradation losses in the design of the privacy-enhancing control strategy, significant improvement in battery life can be achieved, in general, at the expense of some privacy loss.

  • 141. Axelsson, Jakob
    et al.
    Nyfjord, Jaana
    Papatheocharous, Efi
    Törngren, Martin
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Mekatronik.
    Notes On Agile and Safety-Critical Development2015Konferensbidrag (Övrigt vetenskapligt)
  • 142.
    Ayddan, Jonas
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Özbek, Emin
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Transformer test bench -implementation and usability2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    En transformatortestbänk avsedd för laborationer inom forskning och utbildning har utvecklats, där fokus har lagts på säkerhet och användbarhet, eftersom arbete med höga spänningar medför säkerhetsrisker.

    En bänk modierades för att möjliggöra fastsättning av moduler samt

    banankontakter. Vidare anskaades elektroniska komponenter, bearbetades

    och installerades. En design med en magnetisk switch samt lättanvända

    kretsar föreslogs. Dessutom skrevs en kod i LabVIEW med ett brett

    användningsområde. Ett  flertal tester utfördes på en enfastransformator

    och en trefastransformator med syfte att säkerställa att komponenter-

    na fungerar väl ihop med den framtagna transformatortestbänken. En

    del komplikationer uppstod på grund av slumpmässigt, additivt brus.

    Detta gick dock att undertrycka. Det slutliga resultatet visade att kom-

    ponenterna fungerade väl ihop med den framtagna transformatortestbänken.

    Slutligen skrevs en användarmanual med syfte att instruera använda-

    re av transformatortestbänken beträande kopplingarna, testerna samt

    mjukvaran som är skriven i LabVIEW.

  • 143.
    Babu, Sajeesh
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Reliability Evaluation of Distribution ArchitecturesConsidering Failure Modes and Correlated Events2015Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Power systems are in a phase of automation where intelligent components and sub-systems are employed to monitor, control and manage the grid. Quantifying the complex consequences on system reliability, from the integration of such automated and semi-automated equipment into the existing grid is important for maintenance optimisation and fault mitigation. This thesis identifies the  advanced approaches in power system reliability analysis with the potential to capture the complications and correlations in modern power grid after reviewing the traditional reliability evaluation methods.

    A method for modelling the different modes of failures, possible in a substation and feeder architecture along with the probable false tripping scenarios was developed. An improved Reliability Block Diagram based approach was designed to count in the traditionally unaccounted failure cases affecting both the primary grid and the protectionand control equipment. The effect and corresponding trend of additional feeder lines in a radial distribution system on the net interruption rate experienced at load ends of feeders are derived and modelled. Such real-world substation architectures are analysed and the aforementioned trends are compared with those from the practical grid. Thus, the analysis was able to identify and measure the complex hidden failure probabilities due to both unwanted operation of breakers and functional failure of protection systems.

    The measured probabilities were used to calculate the impact of protection and control equipment on system  reliability. The obtained results were verified by comparing it with the observations by energy researchers on ten years of protection system failure statistics. The application of the model and results, in optimal maintenance planning and power network optimisation are identified as the next step.

  • 144.
    Babu, Sajeesh
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Reliability Evaluation of Distribution Systems Considering Failure Modes and Network Configuration2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Eldistributionsnätet är den del av elnäten som leder till flest kundarbrott trots att felhändelserna oftast är mycket lokala jämfört med händelse på genererings och transmissions sidan. Alltså identifieras de olika aspekterna beträffande pålitlighet och prestanda för distributionssystem som viktiga ämnen. Integration av ny teknik, automatisering och ökad penetration av distribuerad produktion förväntas göra förbättringar och rent av upprätthållande av höga tillförlitlighetskrav till en komplex uppgift.

     

    Denna avhandling presenterar metoder för att kvantifiera och analysera de komplexa och korrelerade sannolikheterna för olika fellägen i distributionsnätet. En teoretisk simuleringsmodell baserrad på verkliga data för att mäta sannolikheter för felaktiga brytarkommandon utvecklas och testas. Mer förenklade tillvägagångssätt där elnätsföretag kan använda lättillgängliga data i felregister presenteras också. Optimala konfigurationer som kan förbättra systemprestandan och investeringskostnader analyseras och minskningar i systemets tillförlitlighet genom minskade kostnader för nätinvesteringar modelleras. Optimeringen bidrar till att prioritera kritiska investeringar genom att påvisa systemets inverkan av omkonfigurationer. Optimeringen tär hänsyn till kundernas krav och att bevara överföringsförmågan hos svaga länkar. Värdet av befintliga nät och villigheten hos nätägaren att investera kan undersökas som förslag, till ändringar, som stöd detta för beslut om planering och underhåll.

     

    Avhandlingen gör både systemspecifika och generaliserbara observationer från en detaljerad datainsamling från elnätägare. Observationerna och resultaten har potential att hjälpa framtida forskning genom att ge en viktig förståelse för tillförlitlighetseffekter från nätverksstrukturen och från kontroll- och skyddsutrustning.

  • 145.
    Babu, Sajeesh
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    System Reliability CentredDistribution Network Reconfiguration Considering Investment and Outage CostManuskript (preprint) (Övrigt vetenskapligt)
  • 146.
    Babu, Sajeesh
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Hilber, Patrik
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Reliability and Sensitivity Analysis of Substation and Feeder DesignConsidering Correlated Failures2017Konferensbidrag (Refereegranskat)
  • 147.
    Babu, Sajeesh
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Hilber, Patrik
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Shayesteh, Ebrahim
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Enarsson, Lars Einar
    Reliability Evaluation of Distribution Structures Considering the Presence of False Trips2018Ingår i: IEEE Transactions on Smart Grid, ISSN 1949-3053, E-ISSN 1949-3061Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a method for modelling the different modes of failures in a substation and feeder architecture along with updating the possible false tripping scenarios in it. A traditional approach to collectively assess the failure modes using reliability block diagram is reviewed, and the method is updated to count in the unaccounted false tripping scenarios. A generalizable radial feeder branching structure is adopted and the effect of total feeder length and number of feeders from each busbar is examined and modelled with the help of the updated reliability block diagram. The modelled trends are also studied from real-world substation architectures. Thus, the analysis attains an improved estimation of the complex hidden failure probabilities combining theoretical and practical models.

  • 148.
    Babu, Sajeesh
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Jürgensen, Jan Henning
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Wallnerström, Carl Johan
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Hilber, Patrik
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Tjernberg, Lina Bertling
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Analyses of Smart Grid Technologies and Solutions from a System Perspective2015Ingår i: Smart Grid Technologies - Asia (ISGT ASIA), 2015 IEEE Innovative, IEEE conference proceedings, 2015, s. 1-5, artikel-id 7387089Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper consolidates the data, analysis andobservations from a case study conducted in cooperation withthe Smart Grid Gotland project. The analysis identifies howelectrical power consumption interacts with distributedelectricity generation such as wind and solar power andpresents how it correlates to weather data and smart gridsolutions. The analysis model developed based on the Gotlandnetwork is generic and hence can be functional in investigatingother power networks of different size, voltage level andstructures. The key observations from the study of smart gridsolutions such as dynamic load capacity and energy storagesolutions are specified. Based on the project, an overview offuture risks and opportunities of smart grid systems is presented.

  • 149.
    Babu, Sajeesh
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Shayesteh, Ebrahim
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Hilber, Patrik
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Analysing Correlated Events in Power System Using Fault Statistics2016Ingår i: Probabilistic Methods Applied to Power Systems (PMAPS), 2016 International Conference on, IEEE, 2016Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Power system automation requires logical presumptions made on practical grids to correctly comprehend and manage complex and correlated faults occurring in real world systems. Traditional grid fault analysis methods lack in-depth understanding of these complex events and demand development of approaches that make use of available data to address this problem. Here, the traditional classification approach and challenges relating control equipment in power system are reviewed and a method observing the affected customers during faults along with grid design is discussed based on Swedish case study data. Various contrasting observations are made on the data recorded over two time periods to understand the trend developing over years. Moreover, it will be shown that the classification method also has potential in identifying weak spots in the grid when it comes to the reliability of control equipment.

  • 150.
    Baccino, Francesco
    et al.
    University of Genova – Italy.
    Massucco, Stefano
    University of Genova – Italy.
    Sandels, Claes
    KTH, Skolan för elektro- och systemteknik (EES), Industriella informations- och styrsystem.
    Nordström, Lars
    KTH, Skolan för elektro- och systemteknik (EES), Industriella informations- och styrsystem.
    Technical analysis of an aggregator's operation for the Gotland power system2013Ingår i: 22nd International Conference and Exhibition on Electricity Distribution (CIRED 2013), 2013, s. 1017-Konferensbidrag (Refereegranskat)
    Abstract [en]

    The large scale deployment of distributed generation from renewable energy sources may undermine the network safe operation and may require network reinforcements. In order to avoid or postpone the infrastructural investments it is possible to exploit other resources. In this paper the operation of a load aggregator is simulated on the Swedish island of Gotland in different wind penetration condition to test two different business models, one oriented to the price following and the other oriented to the wind following. The adopted methodology is described and the results presented and commented.

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