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  • 251.
    Bertling, Lina
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Larsson, Mats B-O
    MML Åhus.
    Wallnerström, Carl Johan
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Review of the Swedish Network Performance Assessment Model2008Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The Swedish energy agency (STEM), has developed a new regulatory model to supervise the revenues of the Distribution System Operators (DSO), referred to as the Network Performance Assessment Model (NPAM). The fundamental idea of the NPAM is that the electrical distribution system provides customer values, and the DSO is allowed to collect revenue corresponding to these values. The NPAM calculates customer values for a fictive electrical distribution system, with a total cost referred to as the Network Performance Assessment (NPA). The allowed debiting rate for a DSO is defined by the quotient of the revenue and the NPA. If the debiting rate is higher than a certain value, defined by the Energy Market Inspection (EMI) at STEM, the DSO is placed under review and could be forced to pay back revenue to customers. A lawsuit is currently in progress on this use of the NPAM, which has highlighted drawbacks in the model. This paper provides a comprehensive presentation of the NPAM. It describes in detail the different input data for the model, the steps in the calculations and the resulting cost factors. The paper also presents for the first time details on the theory underlying the calculations.

  • 252.
    Bertling, Lina M.
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    On evaluation of RCM for maintenance management of electric power systems2005Ingår i: 2005 IEEE POWER ENGINEERING SOCIETY GENERAL MEETING, 2005, s. 2638-2640Konferensbidrag (Refereegranskat)
    Abstract [en]

    This panel presentation aims to propose a possible solution for how to evaluate the effect of RCM as a tool for maintenance management. The starting point is a general understanding of the RCM methodology. Further on, a quantitative approach for relating the impact of component maintenance on system reliability and total cost is introduced. The method, referred to as reliability-centred asset maintenance method (RCAM) is being developed within a research group at KTH in Sweden. Finally the presentation comments on ongoing research to evaluate the introduction of RCM. The aim of RCM is to optimize the maintenance achievements in a systematic way.

  • 253.
    Bertling, Lina M.
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    Allan, R
    Eriksson, Roland
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska energisystem.
    A reliability-centred asset maintenance method for assessing the impact of maintenance in power distribution systems2005Ingår i: 2005 IEEE Power Engineering Society General Meeting, 2005, s. 2649-2649Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper proposes a method for comparing the effect of different maintenance strategies on system reliability and cost. This method relates reliability theory with the experience gained from statistics and practical knowledge of component failures and maintenance measures. The approach has been applied to rural and urban distribution systems. In particular, a functional relationship between failure rate and maintenance measures has been developed for a cable component. The results show the value of using a systematic quantitative approach for investigating the effect of different maintenance strategies.

  • 254.
    Bertling, Lina
    et al.
    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.
    Nätnyttomodellens tillförlitlighet med avseende på små förändringar i indata2006Rapport (Övrigt vetenskapligt)
  • 255.
    Bessegato, Luca
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Harnefors, Lennart
    Ilves, Kalle
    Norrga, Staffan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    A Method for the Calculation of the AC-Side Admittance of a Modular Multilevel Converter2018Ingår i: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Connecting a modular multilevel converter to anac grid may cause stability issues, which can be assessed byanalyzing the converter ac-side admittance in relation to the gridimpedance. This paper presents a method for calculating theac-side admittance of modular multilevel converters, analyzingthe main frequency components of the converter variables individually.Starting from a time-averaged model of the converter,the proposed method performs a linearization in the frequencydomain, which overcomes the inherent nonlinearities of theconverter internal dynamics and the phase-locked loop usedin the control. The ac-side admittance obtained analytically isfirstly validated by simulations against a nonlinear time-averagedmodel of the modular multilevel converter. The tradeoff posedby complexity of the method and the accuracy of the result isdiscussed and the magnitude of the individual frequency componentsis shown. Finally, experiments on a down-scaled prototypeare performed to validate this study and the simplification onwhich it is based.

  • 256.
    Bessegato, Luca
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Ilves, Kalle
    Harnefors, Lennart
    Norrga, Staffan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Effects of Control on the AC-Side Admittance of a Modular Multilevel Converter2019Ingår i: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107, Vol. 34, nr 8, s. 7206-7220, artikel-id 8514034Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The stability of a modular multilevel converter connected to an ac grid can be assessed by analyzing the converter ac-side admittance in relation to the grid impedance. The converter control parameters have a strong impact on the admittance and they can be adjusted for achieving system stability. This paper focuses on the admittance-shaping effect produced by different current-control schemes, either designed on a per-phase basis or in the $dq$ frame using space vectors. A linear analytical model of the converter ac-side admittance is developed, including the different current-control schemes and the phase-locked loop. Different solutions for computing the insertion indices are also analyzed, showing that for a closed-loop scheme a compact expression of the admittance is obtained. The impact of the control parameters on the admittance is discussed and verified experimentally, giving guidelines for designing the system in terms of stability. Moreover, recommendations on whether a simplified admittance expression could be used instead of the detailed model are given. The findings from the admittance-shaping analysis are used to recreate a grid-converter system whose stability is determined by the control parameters. The developed admittance model is then used in this experimental case study, showing that the stability of the interconnected system can be assessed using the Nyquist stability criterion.

  • 257.
    Bessegato, Luca
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Modeer, Tomas
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Norrga, Staffan
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Modeling and control of a tapped-inductor buck converter with pulse frequency modulation2014Ingår i: Energy Conversion Congress and Exposition (ECCE), 2014 IEEE, 2014, s. 3672-3678Konferensbidrag (Refereegranskat)
    Abstract [en]

    The tapped-inductor buck (TI-buck) converter has shown to be a suitable solution for auxiliary power supply for modular multilevel converter submodules. Such application features a large step-down voltage conversion, made at relatively low output power. This converter operates in discontinuous conduction mode with zero voltage switching of the high-voltage valve. This paper treats the dynamic behaviour of the aforementioned converter. First, an average output current model of the converter is developed and a small signal model is obtained. Then, a closed-loop output voltage control, which uses the switching frequency as control variable, is designed and implemented using a microcontroller. Measurements on a down-scaled prototype shows that the control system provides a well-controlled average output voltage, which is stable under significant load variation. Finally, a solution for implementing the start-up of the converter is presented and tested.

  • 258.
    Bessegato, Luca
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Narula, Anant
    Bakas, Panagiotis
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Norrga, Staffan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Design of a Modular Multilevel Converter Prototype for Research Purposes2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    As modular multilevel converters gradually become the preferred topology for many high-voltage andhigh-power applications, they are widely studied among researchers, who need experimental results tovalidate their studies. This paper discusses the design of a down-scaled modular multilevel converterprototype for research purposes, equipped with 30 full-bridge submodules and 10 kW rating. The designof this prototype is aimed at safety, flexibility, orderliness, and compactness. The challenges posed by theimplementation of the converter prototype are examined, discussing the design of the prototype structure,the communication scheme, the full-bridge submodules, and the control hierarchy. The control systemis based on Xilinx Zynq system-on-chip, which integrates programmable logic and processing system,allowing for extensive computational capability as well as simple reconfiguration. Experimental resultsshowing the prototype in operation at nominal ratings are presented along with the devised graphical userinterface.

  • 259.
    Bessegato, Luca
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Norrga, Staffan
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Ilves, K.
    Harnefors, Lennart
    Ac-side admittance calculation for modular multilevel converters2017Ingår i: 2017 IEEE 3rd International Future Energy Electronics Conference and ECCE Asia, IFEEC - ECCE Asia 2017, Institute of Electrical and Electronics Engineers (IEEE), 2017, s. 308-312Konferensbidrag (Refereegranskat)
    Abstract [en]

    Power electronic converters may interact with the grid, thereby influencing dynamic behavior and resonances. Impedance and passivity based stability criteria are two useful methods that allow for studying the grid-converter system as a feedback system, whose behavior is determined by the ratio of grid and converter impedances. In this paper, the ac-side admittance of the modular multilevel converter is calculated using harmonic linearization and considering five specific frequency components of the converter variables. The proposed model features remarkable accuracy, verified through simulations, and insight into the influence of converter and control parameters on the admittance frequency characteristics, which is useful for understanding grid-converter interaction and designing the system.

  • 260.
    Bessegato, Luca
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Norrga, Staffan
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Ilves, Kalle
    Harnefors, Lennart
    Control of Modular Multilevel Matrix Converters Based on Capacitor Voltage Estimation2016Ingår i: IEEE 8th International Power Electronics and Motion Control Conference (IPEMC-ECCE Asia), 2016, IEEE, 2016, s. 3447-3452, artikel-id 7512848Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, a control method based on capacitor voltage estimation is applied to the modular multilevel matrix converter topology. By using such control method, capacitor voltage measurement is not needed in the high-level control. A state-space model of the converter and the control method is developed. Lyapunov stability theory is used to prove global asymptotic stability of the internal dynamics of the converter. Simulation results showing the behavior of the converter in steady-state and dynamic situations are presented.

  • 261.
    Bessman, Alexander
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Soares, Rudi
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknisk teori och konstruktion.
    Software documentation for current-rippleequipment2018Rapport (Övrig (populärvetenskap, debatt, mm))
  • 262.
    Bessman, Alexander
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Soares, Rúdi Cavalerio
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Behm, Mårten
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Wallmark, Oskar
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Leksell, Mats
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Svens, P.
    Investigating the aging effect of current ripple on lithium-ion cells2015Ingår i: ECS Transactions, Electrochemical Society, 2015, Vol. 69, nr 18, s. 101-106Konferensbidrag (Refereegranskat)
    Abstract [en]

    We have built an experimental setup which exposes twelve cells to a well-defined ripple current. It consists of a system for cycling high capacity cells in parallel with a triangular current waveform superimposed on top of the direct current. The frequency of the waveform is variable up to 50 Hz, and the sum of the DC and AC components can have a magnitude of -40 A to 40 A. Current is measured over a 500 μω shunt resistor. The voltage and current of each cell is read simultaneously at a sample rate up to 4 MS/s, allowing for precise impedance measurements even for high frequency harmonics. The cells are cycled at 40 °C. The experiment has been designed to eliminate indirect effects of the AC harmonics as far as possible. This system is being used to test whether or not AC harmonics affect Li-ion aging.

  • 263.
    Bessman, Alexander
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Soares, Rúdi
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Wallmark, Oskar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Svens, Pontus
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Aging effects of AC harmonics on lithium-ion cells2019Ingår i: Journal of Energy Storage, E-ISSN 2352-152X, Vol. 21, s. 741-749Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With the vehicle industry poised to take the step into the era of electric vehicles, concerns have been raised that AC harmonics arising from switching of power electronics and harmonics in electric machinery may damage the battery. In light of this, we have studied the effect of several different frequencies on the aging of 28 Ah commercial NMC/graphite prismatic lithium-ion battery cells. The tested frequencies are 1 Hz, 100 Hz, and 1 kHz, all with a peak amplitude of 21 A. Both the effect on cycled cells and calendar aged cells is tested. The cycled cells are cycled at a rate of 1C:1C, i.e., 28 A during both charging and discharging, with the exception of a period of constant voltage at the end of every charge. After running for one year, the cycled cells have completed approximately 2000 cycles. The cells are characterized periodically to follow how their capacities and power capabilities evolve. After completion of the test about 80% of the initial capacity remained and no increase in resistance was observed. No negative effect on either capacity fade or power fade is observed in this study, and no difference in aging mechanism is detected when using non-invasive electrochemical methods of post mortem investigation.

  • 264.
    Beuerle, Bernhard
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Campion, James
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Shah, Umer
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Oberhammer, Joachim
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    A Very Low Loss 220–325 GHz Silicon Micromachined Waveguide Technology2018Ingår i: IEEE Transactions on Terahertz Science and Technology, ISSN 2156-342X, E-ISSN 2156-3446, Vol. 8, nr 2, s. 248-250Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This letter reports for the first time on a very low loss silicon micromachined waveguide technology, implemented for the frequency band of 220–325 GHz. The waveguide is realized by utilizing a double H-plane split in a three-wafer stack. This ensures very low surface roughness, in particular on the top and bottom surfaces of the waveguide, without the use of any surface roughness reduction processing steps. This is superior to previous micromachined waveguide concepts, including E-plane and single H-plane split waveguides. The measured average surface roughness is 2.14 nm for the top/bottom of the waveguide, and 163.13 nm for the waveguide sidewalls. The measured insertion loss per unit length is 0.02–0.07 dB/mm for 220–325 GHz, with a gold layer thickness of 1 μm on the top/bottom and 0.3 μm on the sidewalls. This represents, in this frequency band, the lowest loss for any silicon micromachined waveguide published to date and is of the same order as the best metal waveguides.

  • 265.
    Beuerle, Bernhard
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Campion, James
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Shah, Umer
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Oberhammer, Joachim
    Integrated Micromachined Waveguide Absorbers at 220 – 325 GHz2017Ingår i: Proceedings of the 47th European Microwave Conference, Nuremberg, October 8-13, 2017, 2017, s. 695-698Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents the characterization of integrated micromachined waveguide absorbers in the frequency band of 220 to 325 GHz. Tapered absorber wedges were cut out of four different commercially available semi-rigid absorber ma terials and inserted in a backshorted micromachined waveguide cavity for characterization. The absorption properties of these materials are only specified at 10 GHz, and their absorption behavior above 100 GHz was so far unknown. To study the effect of the geometry of the absorber wedges, the return loss of different absorber lengths and tapering angles was investigated. The results show that longer and sharper sloped wedges from the material specified with the lowest dielectric constant, but not the highest specified absorption, are superior over other geometries and absorber materials. The best results were achieved for 5 mm long absorbers with a tapering angle of 23° in the material RS-4200 from the supplier Resin Systems, having a return loss of better than 13 dB over the whole frequency range of 220 to 325 GHz. These absorber wedges are intended to be used as matched loads in micromachined waveguide circuits. To the best of our knowledge, this is the first publication characterizing such micromachined waveguide absorbers.

  • 266.
    Beuerle, Bernhard
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Campion, James
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Shah, Umer
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Oberhammer, Joachim
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Low-Loss Silicon Micromachined Waveguides Above 100 GHz Utilising Multiple H-plane Splits2018Ingår i: Proceedings of the 48th European Microwave Conference, Madrid, October 1-3, 2018, Institute of Electrical and Electronics Engineers (IEEE), 2018, s. 1041-1044, artikel-id 8541605Konferensbidrag (Refereegranskat)
    Abstract [en]

    For sub-millimeter and millimeter wave applications rectangular waveguides are an ideal transmission medium. Compared to conventional, metal-milled rectangular waveguides, silicon micromachined waveguides offer a number of advantages. In this paper we present a low-loss silicon micromachined waveguide technology based on a double H-plane split for the frequency bands of 110 – 170 GHz and 220 – 330 GHz. For the upper band a reduced height waveguide is presented, which achieves a loss per unit length of 0.02 – 0.10 dB/mm. This technology has been further adapted to implement a full height waveguide for the lower frequency band of 110 – 170 GHz. The full height waveguide takes advantage of the benefits of the double H-plane split technique to overcome the challenges of fabricating micromachined waveguides at lower frequencies. With measured insertion loss of 0.007 – 0.013 dB/mm, averaging 0.009 dB/mm over the whole band, this technology offers the lowest insertion loss of any D-band waveguide to date. The unloaded Q factor of the D-band waveguide technology is estimated to be in excess of 1600, while a value of 750 has been measured for the reduced height upper band waveguide.

  • 267.
    Beuerle, Bernhard
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Shah, Umer
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Oberhammer, Joachim
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Micromachined Waveguides with Integrated Silicon Absorbers and Attenuators at 220–325 GHz2018Ingår i: IEEE MTT-S International Microwave Symposium, IEEE conference proceedings, 2018 / [ed] IEEE, IEEE, 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper reports for the first time on micromachined waveguides with integrated micromachined silicon absorbers. In contrast to epoxy-based microwave absorbers, micromachined lossy silicon absorbers are fully compatible with high temperature fabrication and assembly processes for micromachined waveguides. Furthermore, micromachining enables the fabrication of exact, near ideal taper tips for the silicon absorbers, whereas the tip of epoxy-based absorbers cannot be shaped accurately and reproducibly for small waveguides. Silicon of different conductivity is a very well understood and characterized dielectric material, in contrast to conventional absorber materials which are not specified above 60 GHz. Micromachined silicon waveguides with integrated absorbers and attenuators were designed, fabricated and characterized in the frequency band of 220 – 325 GHz. The return and insertion loss for various taper-geometry variations of double-tip tapered absorbers and attenuators was studied. The average return loss for the best investigated device is 19 dB over the whole band. The insertion loss of the two-port attenuators is 16 – 33 dB for different designs and shows an excellent agreement to the simulated results. The best measured devices of the one-port absorbers exhibit an average and worst-case return loss of 22 dB and 14 dB, respectively, over the whole band. The return loss is not characterized by a good simulation-measurement match, which is most likely attributed to placement tolerances of the absorbers in the waveguide cavities affecting the return but not the insertion loss.

  • 268. Bian, D.
    et al.
    Kuzlu, M.
    Pipattanasomporn, M.
    Rahman, S.
    Wu, Yiming
    KTH, Skolan för elektro- och systemteknik (EES), Industriella informations- och styrsystem.
    Real-time Co-simulation Platform using OPAL-RT and OPNET for Analyzing Smart Grid Performance2015Ingår i: 2015 IEEE POWER & ENERGY SOCIETY GENERAL MEETING, IEEE , 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    The objective of this paper is to present a real-time co-simulation platform for analyzing electric power grid operation, taking into account integrated communication systems. This paper discusses how a co-simulation platform can be set up using OPNET and OPAL-RT as communication and power system simulators, respectively. A simplified distribution automation case study is demonstrated to show how the cosimulation platform can be used to analyze performance of the smart grid operation in real-time.

  • 269.
    Bianchi, Adam
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Nylander, Gabriel
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Operation and Control of HVDC Grids2018Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Högspända likströmsnät spelar en allt större roll med att integrera förnyelsebar energi i våra elnät. För att styra dessa nät på bästa möjliga sätt krävs optimala omvandlar- och nätkontrollstrategier. I detta projekt studeras hur ett fyrterminalt högspänt likströmsnät kan styras och drivas genom att implementera olika omvandlar- och nätkontrollstrategier. De nätkontrollstrategier som studerats är centraliserad spänningskontroll och distribuerad spänningskontroll med och utan ett spänningsintervall. Alla simuleringar har utförts i programmet PSCAD. Olika fel i nätet har även studerats för att undersöka hur effektflödet och spänningsnivån påverkas. Ett optimalt värde på både spänningsintervallet och droop konstanten har identifierats. Dessutom har resultat som indikerar att centraliserad spänningskontroll inte är en lämplig nätkontrollstrategi erhållits, medan distribuerad spänningskontroll med och utan spänningsintervall är det. Felsimuleringarna påvisar ingen skillnad mellan distribuerad spänningskontroll med och utan spänningsintervall. Effektflödet och spänningsnivån är identiska för alla fel.

  • 270.
    Bianchi, N.
    et al.
    University of Padova.
    Bolognani, S.
    University of Padova.
    Pré, M. Dai
    University of Padova.
    Tomasini, M.
    University of Padova.
    Peretti, L.
    University of Udine.
    Zigliotto, M.
    University of Udine.
    The steering effect - PM motor drives for automotive systems2008Ingår i: IEEE Industry Applications Magazine, ISSN 1077-2618, Vol. 14, nr 2, s. 40-48Artikel i tidskrift (Refereegranskat)
  • 271. Biehl, Matthias
    et al.
    El-khoury, Jad
    Törngren, Martin
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    Automated tailoring of application life-cycle management systems to existing development processes2013Ingår i: International Journal On Advances in Software, ISSN 1942-2628, E-ISSN 1942-2628, Vol. 6Artikel i tidskrift (Refereegranskat)
  • 272.
    Bisesi, Erica
    et al.
    Centre for Systematic Musicology, University of Graz, Graz, Austria.
    Friberg, Anders
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Tal, musik och hörsel, TMH.
    Parncutt, Richard
    Centre for Systematic Musicology, University of Graz, Graz, Austria.
    A Computational Model of Immanent Accent Salience in Tonal Music2019Ingår i: Frontiers in Psychology, ISSN 1664-1078, E-ISSN 1664-1078, Vol. 10, nr 317, s. 1-19Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Accents are local musical events that attract the attention of the listener, and can be either immanent (evident from the score) or performed (added by the performer). Immanent accents involve temporal grouping (phrasing), meter, melody, and harmony; performed accents involve changes in timing, dynamics, articulation, and timbre. In the past, grouping, metrical and melodic accents were investigated in the context of expressive music performance. We present a novel computational model of immanent accent salience in tonal music that automatically predicts the positions and saliences of metrical, melodic and harmonic accents. The model extends previous research by improving on preliminary formulations of metrical and melodic accents and introducing a new model for harmonic accents that combines harmonic dissonance and harmonic surprise. In an analysis-by-synthesis approach, model predictions were compared with data from two experiments, respectively involving 239 sonorities and 638 sonorities, and 16 musicians and 5 experts in music theory. Average pair-wise correlations between raters were lower for metrical (0.27) and melodic accents (0.37) than for harmonic accents (0.49). In both experiments, when combining all the raters into a single measure expressing their consensus, correlations between ratings and model predictions ranged from 0.43 to 0.62. When different accent categories of accents were combined together, correlations were higher than for separate categories (r = 0.66). This suggests that raters might use strategies different from individual metrical, melodic or harmonic accent models to mark the musical events.

  • 273.
    Bishop, Adrian N.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP. Australian National University, Canberra, Australia.
    Gaussian-sum-based probability hypothesis density filtering with delayed and out-of-sequence measurements2010Ingår i: 18th Mediterranean Conference on Control and Automation, MED'10 - Conference Proceedings, 2010, s. 1423-1428Konferensbidrag (Refereegranskat)
    Abstract [en]

    The problem of multiple-sensor-based multipleobject tracking is studied for adverse environments involving clutter (false positives), missing measurements (false negatives) and random target births and deaths (a priori unknown target numbers). Various (potentially spatially separated) sensors are assumed to generate signals which are sent to the estimator via parallel channels which incur independent delays. These signals may arrive out of order, be corrupted or even lost. In addition, there may be periods when the estimator receives no information. A closed-form, recursive solution to the considered problem is detailed that generalizes the Gaussian-mixture probability hypothesis density (GM-PHD) filter previously detailed in the literature. This generalization allows the GM-PHD framework to be applied in more realistic network scenarios involving not only transmission delays but rather more general irregular measurement sequences where particular measurements from some sensors can arrive out of order with respect to the generating sensor and also with respect to the signals generated by the other sensors in the network.

  • 274.
    Bissal, Ara
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Magnusson, Jesper
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Engdahl, Göran
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Comparison of two Ultra-fast actuator concepts2012Ingår i: IEEE transactions on magnetics, ISSN 0018-9464, E-ISSN 1941-0069, Vol. 48, nr 11, s. 3315-3318Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, two different types of ultra-fast electromechanical actuators are compared using a multi-physical finite element simulation model that has been experimentally validated. They are equipped with a single-sided Thomson coil (TC) and a double-sided drive coil (DSC), respectively. The former consists of a spirally-wound flat coil with a copper armature on top, while the latter consists of two mirrored spiral coils that are connected in series. Initially, the geometry and construction of each of the actuating schemes are discussed. Subsequently, the theory behind the two force generation principles are described. Furthermore, the current, magnetic flux densities, accelerations, and induced stresses are analyzed. Moreover, mechanical loadability simulations are performed to study the impact on the requirements of the charging unit, the sensitivity of the parameters, and evaluate the degree of influence on the performance of both drives. Finally, it is confirmed that although the DSC is mechanically more complex, it has a greater efficiency than that of the TC.

  • 275.
    Bissal, Ara
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Magnusson, Jesper
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Engdahl, Göran
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Optimal Energizing Source Design for Ultra-Fast Actuators2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    One of the key enabling technologies for multi-terminal HVDCgrids is the existence of a breaker that can operate withina few milliseconds. A lot of research has been done to builddifferent ultra-fast drives to actuate the electric contacts ofthese breakers. What they all have in common is an operationalefficiency of at best 5 %. Capacitor banks are discharged throughspirally shaped flat coils to generate ultra-fast repulsive forces. Tooptimize the efficiency of the drive, the design of the energizingcircuit is crucial. The aim of this paper is to optimize theenergizing source and provide a deep explanation of the effectof the chosen capacitance and charging voltage for two actuatorconcepts, the Thomson coil (TC) and the double sided coil (DSC)for different stroke requirements. An experimentally validatedmulti-physics finite element method (FEM) simulation model is applied.

  • 276.
    Bissal, Ara
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion. ABB Corporate Research.
    Salinas, E.
    Magnusson, Jesper
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Engdahl, Göran
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    On the design of a linear composite magnetic damper2015Ingår i: 2015 IEEE International Magnetics Conference, INTERMAG 2015, IEEE conference proceedings, 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    In recent years, ultra-fast actuators have become key elements in the development of high voltage direct current (HVDC) breakers for multiterminal grids which represent a huge progress in modern power transmission [1]. After fulfilling their operation these actuators need to be decelerated using controllable forces to avoid deforming vital components incorporated in the system. In this paper, a dedicated damper is proposed based on a magnet array that induces eddy currents in a composite metal tube resulting in an efficient braking response. Several topologies are investigated by simulations and experiments. The theory behind eddy current damping is explained in [2]. The main requirements for such dampers are reliability, robustness, and ease of construction. The expected durability of these kind of dampers is longer than the breaker itself which guarantees extremely good reliability within HVDC systems.

  • 277.
    Bissal, Ara
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Salinas, Ener
    Magnusson, Jesper
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Engdahl, Göran
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    On the Design of a Linear Composite Magnetic Damper2015Ingår i: IEEE transactions on magnetics, ISSN 0018-9464, E-ISSN 1941-0069, Vol. 51, nr 11, artikel-id 8003305Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High-voltage direct current (HVdc) breakers are the key components in the realization of multiterminal HVdc grids. In the presence of fault current, these breakers should be able to deliver impulsive forces to swiftly open the metallic contacts. After the acceleration phase, the moving armature should be decelerated using controllable forces to avoid plastically deforming fragile components integrated in the system. In this paper, finite-element method-based simulation models, complimented with small-scale and large-scale experimental prototypes, were utilized to benchmark different damping topologies. It was found that a Halbach-based configuration can deliver a damping force that is almost two and a half times larger than its sequel. Its sequel, composed of vertically stacked oppositely oriented magnets, is easier to assemble and is also capable of generating a considerable damping force. Finally, it has been shown that both these schemes, inserted in a composite tube, have a potential to be used as dampers in HVdc breakers.

  • 278.
    Bitsi, Konstantina
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Kowal, Damian
    Moghaddam, Reza-Rajabi
    3-D FEM Investigation of Eddy Current Losses in Rotor Lamination Steel Sheets2018Ingår i: 2018 XIII International Conference on Electrical Machines (ICEM), IEEE conference proceedings, 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, a test setup that emulates field conditions equivalent to the ones of the rotor of a Salient Pole Synchronous Machine (SPSM) is presented. A 3-D Finite Element Method (FEM) model of the test setup is used to examine the induced eddy currents and to estimate losses using direct eddy current calculation method. The high mesh resolution of the model enables an accurate calculation and detailed illustration of the induced eddy currents as well as the estimation of related losses via direct computation within the volume of the test samples. A comparison of the estimated eddy current losses is made for different lamination thicknesses and materials of the test object. In the paper it is shown that the approximation that the eddy current losses are directly proportional to the square of the lamination thickness is not valid in the considered cases.

  • 279.
    Bitsi, Konstantina
    et al.
    ABB Corporate Research, Västerås, Sweden.
    Kowal, Damian
    Rajabi Moghaddam, Reza
    Novel approach in investigating the rotor lamination iron losses2017Ingår i: 2017 IEEE International Electric Machines and Drives Conference (IEMDC), IEEE conference proceedings, 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a 2-D design of a measurement setup that subjects laminated steel to field conditions corresponding to the ones of the rotor in a Salient Pole Synchronous Machine (SPSM). This stationary setup exposes the test samples to traveling magnetic waves in an air-gap. The purpose of this setup is to simulate the eddy current losses that result from high frequency magnetic fields within the volume of the test samples. The investigation of the design and the dimensioning of the model is conducted in a 2-D Finite Element Method (FEM) model. The study shows that it is possible to emulate traveling sinusoidal magnetic flux in the air-gap of a setup excluding motion. A rectangular shape of the setup was chosen due to the expected flexibility of the design as well as easy manufacturing. It was found that in order to achieve a constant amplitude of the traveling wave in the air-gap an implementation of an auxiliary winding is an effective solution.

  • 280. Bjurman, Ulf
    et al.
    Engdahl, Göran
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Separation of high and low frequency behavior in non linear circuit simulation excited with modulated signals1999Ingår i: Proc of the 12:th Conference on Computation of Electromagnetic Fields, Sapporo Japan, 1999, s. 260-61Konferensbidrag (Refereegranskat)
  • 281.
    Björck, Linnea
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Petersen, Johan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Hälsoinformatik och logistik.
    Höjdmätare för fallskärmshoppning: Metoder för höjdmätning samt framtagning av algoritmer för vald metod2019Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Inom fallskärmshoppning behövs förutom ett välfungerande fallskärmssystem även en precis höjdmätare. Båda är avgörande komponenter när det gäller utrustning för att kunna genomföra ett säkert hopp. Genom digitalisering och den tekniska utvecklingen finns det idag intressen för att ta fram en digital höjdmätare med bättre precision, flera funktioner och bättre samt tydligare användargränssnitt.

    Det existerar ett flertal tekniker för mätning av höjd. De tekniker som tas upp i examensarbetet är global positioning system (GPS), radar och barometer. Målet med examensarbetet var att ta fram en robust algoritm för mätning av höjd, med möjlighet till utveckling. Examensarbetet skulle även innehålla riskanalys av vald(a) teknik(er) , samt förslag på lämpliga presentationstekniker och systemlösningar satt i ett större perspektiv. Systemlösningarna skulle vara anpassade för enkel integration av nya funktioner. I mån av tid skulle även en prototyp utvecklas samt testas.

    Metoden som valdes var en digital höjdmätare på grund av att den passade bäst för det mål som upprättats för projektet. Fr att beräkna höjden med den digitala höjdmätaren användes sambandet mellan lufttryck och höjd. Resultatet av dessa beräkningar visade på ett tillräckligt precist mätvärde för att vara godtagbart. Eftersom mätvärdets precision var godtagbar beslutades det att inga ytterligare rättningar skulle göras. Arbetet fortsattes med att utveckla en prototyp och testning av denna utfördes. Resultatet blev att en fungerande prototyp togs fram. Framtida utvecklingsmöjligheter finns inom presentationsteknik, chassi, ytterligare rättningar av formeln för höjdmätning och fler iterationer av hårdvaran.

  • 282.
    Björk, Joakim
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Johansson, Karl Henrik
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Harnefors, Lennart
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Fundamental Performance Limitations in Utilizing HVDC to Damp Interarea Modes2019Ingår i: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679, Vol. 34, nr 2, s. 1095-1104Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper considers power oscillation damping (POD) using active power modulation of high-voltage dc transmissions. An analytical study of how the proximity between interarea modal frequencies in two interconnected asynchronous grids puts a fundamental limit to the achievable performance is presented. It is shown that the ratio between the modal frequencies is the sole factor determining the achievable nominal performance. To illustrate the inherent limitations, simulations using a proportional controller tuned to optimize performance in terms of POD are done on a simplified two-machine model. The influence of limited system information and unmodeled dynamics is shown. The analytical result is then further validated on a realistic model with two interconnected 32-bus networks.

  • 283.
    Björk, Joakim
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Johansson, Karl Henrik
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Harnefors, Lennart
    ABB, Corp Res, Vasteras, Sweden..
    Eriksson, Robert
    Svenska kraftnat, R&D, Sundbyberg, Sweden..
    Analysis of Coordinated HVDC Control for Power Oscillation Damping2018Ingår i: Conference Record of the 3rd IEEE International Workshop on Electronic Power Grid, eGrid 2018, Institute of Electrical and Electronics Engineers (IEEE), 2018, s. 19-24, artikel-id 8598674Konferensbidrag (Refereegranskat)
    Abstract [en]

    Controlling the active power of high-voltage de (HVDC) transmission that interconnects two asynchronous ac grids can be used to improve the power oscillation damping in both of the interconnected ac systems. Using one HVDC link, achievable performance are limited since control actions may excite modes of similar frequencies in the assisting network. However, with coordinated control of two or more HVDC links, the limitations can be circumvented. With decoupling control the system interactions can be avoided all together. This paper investigates the conditions suitable for decoupling control. It is also shown that decoupling between system modes can be achieved using a proportional controller. The control method is compared to decentralized and H-2 optimal control. The best control method for different system topologies is investigated by looking on input usage and stability following dc link failure.

  • 284.
    Björklund, Johan
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Prestandautvärdering av permanentmagnetmotor2014Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Examensarbetet var en utvärdering av en synkron trefas permanentmagnetmotor med utvändig rotor. Den är tänkt att ingå i ett batterimatat drivsystem för hjälputrustning på segelbåtar. Målen var att kartlägga prestandan i standardutförande samt att hitta de svaga punkterna i konstruktionen. Förslag på hur motorutförandet kan optimeras ska också läggas fram.

     

    Tester och mätningar gjordes i en testuppkoppling med växelriktare, motor och axelkopplad generator. Detta för att kunna få fram fler mätvärden på motorn. Generatorn fick varvtalskortslutning när belastningsströmmen kom upp i 106,1 A och testerna fick avslutas. Koppartråden i lindningarna blev för varm och ytskiktet smälte. Testerna visar att motorn klarar av strömmar upp till 92,1 A och har då en verkningsgrad på 70 %. Det var lindningens strömtålighet tillsammans med effektförlusterna som var den begränsande faktorn i motorkonstruktionen.

     

    Forcerad kylning i form av vattenkyld stator eller att öka lindningstrådens strömtålighet genom att t.ex. en större kabelarea är alternativ för att få till en bättre verkningsgrad och motorprestanda. Ser man till externa lösningar skulle luftkylning med fläkt kunna adderas.

  • 285.
    Björkqvist, Oskar
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknisk teori och konstruktion.
    Dahlberg, Oskar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknisk teori och konstruktion.
    Quevedo-Teruel, Oscar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknisk teori och konstruktion.
    Additive Manufactured Three Dimensional Luneburg Lens for Satellite Communications2019Ingår i: 13th European Conference on Antennas and Propagation, EuCAP 2019, Institute of Electrical and Electronics Engineers (IEEE), 2019, artikel-id 8739803Konferensbidrag (Refereegranskat)
    Abstract [en]

    A method for designing gradient refractive index (GRIN) lenses with additive manufacturing or 3D-printing at K-u band is presented. To demonstrate the potential of the method, we designed a Luneburg lens using a single low-loss dielectric material available for 3D-printers. The gradient index is realized by varying the local material fill density of the lens. We demonstrate with full wave simulations that the structure is able to transform a spherical electromagnetic wave to a plane wave. When the lens is fed with a rectangular waveguide, the overall antenna has a gain of 23 dBi with side lobe levels of -12.5 dB in K-u band. This lens, when integrated with a circular polarized feeding system, could find application for ground satellite communications.

  • 286.
    Björnson, Emil
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Signalbehandling. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Ottersten, Björn
    KTH, Skolan för elektro- och systemteknik (EES), Signalbehandling. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    On the Principles of Multicell Precoding with Centralized and Distributed Cooperation2009Ingår i: 2009 INTERNATIONAL CONFERENCE ON WIRELESS COMMUNICATIONS AND SIGNAL PROCESSING (WCSP 2009), NEW YORK: IEEE , 2009, s. 1644-1648Konferensbidrag (Refereegranskat)
    Abstract [en]

    Cooperative precoding is an attractive way of improving the performance in multicell downlink scenarios. By serving each terminal through multiple surrounding base stations, inter-cell interference can be coordinated and higher spectral efficiency achieved, especially for terminals at cell edges. The optimal performance of multicell precoding is well-known as it can be treated as a single cell with distributed antennas. However, the requirements on backhaul signaling and computational power scales rapidly in large and dense networks, which often makes such fully centralized approaches impractical. In this paper, we review and generalize some recent work on multicell precoding with both centralized and distributed cooperation. We propose practical precoding strategies under Rician channel conditions, and illustrate how the major gain of multicell precoding originates from having good base station synchronization and not from making centralized precoding decisions.

  • 287.
    Bleiker, Simon J.
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Dubois, Valentin J.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Schröder, Stephan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Ottonello Briano, Floria
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Gylfason, Kristinn B.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Stemme, Göran
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Niklaus, Frank
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Adhesive Wafer Bonding for Heterogeneous System Integration2018Ingår i: ECS Meeting Abstracts / [ed] The Electrochemical Society, 2018Konferensbidrag (Refereegranskat)
  • 288.
    Bleiker, Simon J.
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Visser Taklo, Maaike Margrete
    Department of Instrumentation, SINTEF ICT, Norway.
    Lietaer, Nicolas
    Department of Microsystems and Nanotechnology, SINTEF ICT, Norway.
    Vogl, Andreas
    Department of Microsystems and Nanotechnology, SINTEF ICT, Norway.
    Bakke, Thor
    Department of Microsystems and Nanotechnology, SINTEF ICT, Norway.
    Niklaus, Frank
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Cost-Efficient Wafer-Level Capping for MEMS and Imaging Sensors by Adhesive Wafer Bonding2016Ingår i: Micromachines, ISSN 2072-666X, E-ISSN 2072-666X, Vol. 7, nr 10, s. 192-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Device encapsulation and packaging often constitutes a substantial part of the fabrication cost of micro electro-mechanical systems (MEMS) transducers and imaging sensor devices. In this paper, we propose a simple and cost-effective wafer-level capping method that utilizes a limited number of highly standardized process steps as well as low-cost materials. The proposed capping process is based on low-temperature adhesive wafer bonding, which ensures full complementary metal-oxide-semiconductor (CMOS) compatibility. All necessary fabrication steps for the wafer bonding, such as cavity formation and deposition of the adhesive, are performed on the capping substrate. The polymer adhesive is deposited by spray-coating on the capping wafer containing the cavities. Thus, no lithographic patterning of the polymer adhesive is needed, and material waste is minimized. Furthermore, this process does not require any additional fabrication steps on the device wafer, which lowers the process complexity and fabrication costs. We demonstrate the proposed capping method by packaging two different MEMS devices. The two MEMS devices include a vibration sensor and an acceleration switch, which employ two different electrical interconnection schemes. The experimental results show wafer-level capping with excellent bond quality due to the re-flow behavior of the polymer adhesive. No impediment to the functionality of the MEMS devices was observed, which indicates that the encapsulation does not introduce significant tensile nor compressive stresses. Thus, we present a highly versatile, robust, and cost-efficient capping method for components such as MEMS and imaging sensors.

  • 289.
    Blinov, Andrei
    et al.
    KTH.
    Norrga, Staffan
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Tibola, G.
    Operation of single-chip MOSFET and IGBT devices after failure due to repetitive avalanche: University in collaboration with industry2015Ingår i: Power Electronics and Applications (EPE’15 ECCE-Europe), 2015 17th European Conference on, 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents analysis of post-failure behaviour of MOSFETs and IGBTs operating in a series connected string. The aim of this experimental study is to analyse the operation of devices in case of sudden loss of controllability, leading to repetitive avalanche conditions at relatively low current and subsequent failure due to overheat. For redundant designs it is important that the devices are locked in stable conducting state after the failure and the string continue its operation.

  • 290.
    Blinov, Andrei
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling. Tallinn University of Techmology, Estonia.
    Vinnikov, D.
    Ivakhno, V.
    Full soft-switching high step-up DC-DC converter for photovoltaic applications2014Ingår i: 16th European Conference on Power Electronics and Applications (EPE'14-ECCE Europe), 2014, Lappeenranta: IEEE conference proceedings, 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper a full soft-switching high step-up DC-DC converter is introduced as an alternative approach to module integrated converters for photovoltaic applications. The presented operation principle and key equations can be used as design guidelines for component and parameter estimation in practical applications. The proposed DC-DC converter was verified by help of simulations and experiments. Power loss analysis based on the semiconductor datasheet values showed that the converter tends to achieve an efficiency of 92.8% at the maximum power point.

  • 291.
    Bolognani, S.
    et al.
    University of Padova.
    Faggion, A.
    University of Padova.
    Peretti, L.
    University of Padova.
    Sgarbossa, L.
    University of Padova.
    Modelling and design of a direct-drive lift control with rope elasticity and estimation of starting torque2007Ingår i: IECON 2007 - 33rd Annual Conference of the IEEE Industrial Electronics Society, IEEE conference proceedings, 2007, s. 828-832Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper deals with position control of a direct drive rope-based lift system at mechanical brake releasing. The electrical equipment includes a high-torque, low-speed permanent magnet synchronous motor with external rotor directly connected to the rope pulley. The drive uses only stator current sensors for torque control and an incremental encoder on the motor shaft. A detailed model of the system, which comprises also rope elasticity, is presented, as wells as a load torque estimation algorithm and a feedforward action on the torque reference signal. Such reference is used to reduce the cabin falling down at brake releasing below a perceptible threshold. Final experimental results support the mathematical theory outlined in the paper, validating the proposed control strategy.

  • 292.
    Bolognani, S.
    et al.
    University of Padova.
    Faggion, A.
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