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  • 201. Sharifabadi, K.
    et al.
    Harnefors, L.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Norrga, Staffan
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Teodorescu, R
    Design, control and application of modular multilevel converters for HVDC transmission systems2016Book (Other academic)
    Abstract [en]

    Design, Control and Application of Modular Multilevel Converters for HVDC Transmission Systems is a comprehensive guide to semiconductor technologies applicable for MMC design, component sizing control, modulation, and application of the MMC technology for HVDC transmission. Separated into three distinct parts, the first offers an overview of MMC technology, including information on converter component sizing, Control and Communication, Protection and Fault Management, and Generic Modelling and Simulation. The second covers the applications of MMC in offshore WPP, including planning, technical and economic requirements and optimization options, fault management, dynamic and transient stability. Finally, the third chapter explores the applications of MMC in HVDC transmission and Multi Terminal configurations, including Supergrids. Key features: Unique coverage of the offshore application and optimization of MMC-HVDC schemes for the export of offshore wind energy to the mainland. Comprehensive explanation of MMC application in HVDC and MTDC transmission technology. Detailed description of MMC components, control and modulation, different modeling approaches, converter dynamics under steady-state and fault contingencies including application and housing of MMC in HVDC schemes for onshore and offshore. Analysis of DC fault detection and protection technologies, system studies required for the integration of HVDC terminals to offshore wind power plants, and commissioning procedures for onshore and offshore HVDC terminals. A set of self-explanatory simulation models for HVDC test cases is available to download from the companion website. This book provides essential reading for graduate students and researchers, as well as field engineers and professionals who require an in-depth understanding of MMC technology.

  • 202.
    Shisha, Samer
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Sadarangani, Chandur
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Loss Distribution on Solid Pole Plates of Wound-Rotor Synchronous Motors Fed From Inverters Using Direct Torque Control2012In: IEEE transactions on energy conversion, ISSN 0885-8969, E-ISSN 1558-0059, Vol. 27, no 1, p. 63-70Article in journal (Refereed)
    Abstract [en]

    The use of VSD (variable speed drives) is becoming prominent in industry as it has the benefit of being more energy efficient than conventional process-control mechanisms (such as throttling). VSD usually rely on the use of inverters to produce the required frequency output, which contains time harmonics that eventually induce excess losses in the machine. These losses are the subject of analysis in this study. The results show that it is possible to influence the induced current magnitude (due to the space and time harmonics) through proper design modifications, as to reduce the consequent losses. The paper focuses specifically on DTC (direct torque control) VSD application on solid pole plate synchronous machines. One of the observed effects is that the time and space harmonics are distributed differently on the pole plates.

  • 203.
    Shisha, Samer
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion. Scania.
    Sadarangani, Chandur
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    The Effect of Copper Coating on the Losses in the Solid Pole-Plates of Inverter-Fed Wound Rotor Synchronous Machines2013In: IEEE transactions on energy conversion, ISSN 0885-8969, E-ISSN 1558-0059, Vol. 28, no 2, p. 298-307Article in journal (Refereed)
    Abstract [en]

    The use of solid rotor and pole-plate synchronous machines has several advantages, among which is the fact that it provides a more robust rotor compared to laminated equivalents. This paper investigates the time and space harmonic losses in solid rotor synchronous machines. The work considers the use of copper coating on the pole-plates, studying the effect that this design modification has on the losses. A recommendation is given based on this study, which is considered to reduce the time harmonic losses without detrimental effects as far as the space harmonic losses are considered.

  • 204.
    Soulard, Juliette
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Study of the Synchronization of Line-Start Permanent Magnet Synchronous Motors2000In: Proc. of the IEEE Industry Applications Society Annual Meeting, Roma, Italy, October 2000. / [ed] IEEE, 2000, p. 424-431Conference paper (Refereed)
    Abstract [en]

    The synchronization process of three-phase line start permanent magnet synchronous motors (LSPM) with buried magnets and a squirrel-cage is studied in this paper. The goal is to define a pull-in criterion by using a Lyapunov function. A model is first derived and a Lyapunov function is defined using the Lagrange-Charpit method. Experiments and simulations are then compared to check the validity of the model. A criterion to define the capability of synchronization of LSPM motors is then presented. This criterion is used to study the influence of the electrical parameters on the synchronization capability of two four pole LSPM motors. The first experiments proved that the prototypes have greater synchronization capability than the criterion predicts

  • 205.
    Thelin, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Analytical Calculation of the Airgap Flux Density of PM Synchronous Motors with Buried Magnets Including Axial Leakage, Tooth and Yoke Saturations2000In: Proc. of the International Conference on Power Electronics and Variable Speed Drives, London, September 2000. / [ed] IEE, 2000, p. 218-223Conference paper (Refereed)
    Abstract [en]

    It has been shown earlier that the airgap flux density of PM motors with buried magnets can be calculated with a satisfactory result, if saturated iron bridges, axial leakage flux (from 2D-FEM) and teeth saturation are taken into account. In this paper, instead of using 2D-FEM, an analytical expression for the axial reluctance is derived. By including the saturation of rotor and stator yokes, the model is even further improved. The result is a complete analytical model, which takes into account all phenomena mentioned above, and improves the agreement with experimental values.

  • 206.
    Thelin, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Analytical Calculation of the Airgap Flux Density of PM-Motors with Buried Magnets1998In: Proc. of the International Conference on Electrical Machines 1998, 1998Conference paper (Refereed)
  • 207.
    Thelin, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Calculation of the Airgap Flux Density of PM Synchronous Motors with Buried Magnets including Axial Leakage and Teeth Saturation1999In: Proc. of the Electrical Machines and Drives Conference, Canterbury, UK, September 1999 / [ed] IEE, Institution of Electrical Engineers (IEE), 1999, p. 339-345Conference paper (Refereed)
    Abstract [en]

    It has been shown earlier that the airgap flux density of unsaturated PM motors with buried magnets can be calculated analytically, with a satisfactory result, compared to 2D-FEM calculations. By taking axial leakage flux, and stator and rotor teeth saturation into account an improved expression for the airgap flux density, showing better agreement with experiments, is obtained.

  • 208.
    Thelin, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Development and Efficiency Measurements of a Compact 15 kW 1500 r/min Integral Permanent Magnet Synchronous Motor2000In: Proc. of the IEEE Industry Applications Society Annual Meeting, Roma, Italy, October 2000. / [ed] IEEE, 2000, p. 155-162Conference paper (Refereed)
    Abstract [en]

    This paper presents the development of a 15 kW, 1500 r/min integral motor, with the same outer dimensions as an equivalent standard induction motor, but with the possibility of operating with speed control and at a higher efficiency. To make a compact integral motor, a permanent magnet rotor is used, the coils of the line-filter and the coil of the DC-link have been integrated with the stator core, only a small DC-link capacitor is employed, and the motor is controlled without a shaft sensor. Temperature and efficiency measurements on the manufactured prototype machine are performed and the results are very promising.

  • 209.
    Thelin, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    New Integral Motor Stator Design with Integrated Filter Coils1999In: Proc. of the European Conference on Power Electronics and Applications, Lausanne, Switzerland, September 1999. / [ed] EPE, 1999Conference paper (Refereed)
  • 210.
    Thelin, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Suggestions Regarding the Pole-Number of Inverter-Fed PM-Synchronous Motors with Buried Magnets1998In: Proc. of the International Conference on Power Electronics and Variable Speed Drives 1998, Institution of Electrical Engineers (IEE), 1998, p. 544-547Conference paper (Refereed)
    Abstract [en]

    When designing an inverter-fed PM-motor, one is quite free to choose a number of poles which utilizes the machine in a good way. A common rule of thumb is to choose a high pole-number for low-speed motors and vice versa, but there are no sharp borderlines between the different areas. This paper gives a suggestion regarding the pole-number for a desired power and speed of the motor.

  • 211.
    Thelin, Peter
    et al.
    KTH, Superseded Departments, Electrical Systems.
    Nee, Hans-Peter
    KTH, Superseded Departments, Electrical Systems.
    Soulard, Juliette
    KTH, Superseded Departments, Electrical Systems.
    Sadarangani, Chandur
    KTH, Superseded Departments, Electrical Systems.
    Timmerman, Jan
    KTH, Superseded Departments, Electrical Systems.
    Rotor Cage Losses of an Inverter-Fed PMSM investigated with FEM2003In: Proceedings of the European Conference on Power Electronics and Applications, EPE´03, 2003Conference paper (Refereed)
    Abstract [en]

    In the design of a compact inverter-fed buried permanent magnet synchronous motor, the high-frequency losses of the sparse rotor cage - which are difficult to predict - were assumed to be small. To investigate these ohmic high-frequency losses of the rotor cage, fixed-speed time-stepping 2D-FEM calculations have been carried out. The losses due to only the magnets, magnets and sinusoidal currents, high-frequency currents etc., and the actual currents are presented. The actual current wave-forms were obtained from measurements on the manufactured prototype motor.

  • 212.
    Thelin, Peter
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Soulard, Juliette
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Sadarangani, Chandur
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Comparison between Different Ways to Calculate the Induced No-Load Voltage of PM Synchronous Motors using Finite Element Methods2001In: Proc. of the 4th IEEE International Conference on Power Electronics and Drive Systems (PEDS'01), Bali, Indonesia, October 2001, vol. 2. / [ed] IEEE, 2001, p. 468-474Conference paper (Refereed)
    Abstract [en]

    In this paper two different ways of calculating the induced no-load voltage of permanent magnet synchronous motors (PMSM), by the use of a finite element method (FEM) program, have been compared. Neither of the two calculation methods require a FEM software package that can perform time-stepping. The number of required static FEM-calculations is limited to just a few, or even to one. The calculations are performed on five motor geometries. The results are compared to values obtained from time-stepping FEM-calculations, and to the measured induced no-load voltages of the five manufactured prototype motors. It can be seen that the least time-consuming method is accurate enough in most of these cases. The exceptions, in this study, are when there are relatively large airgaps and/or when the stator teeth are saturated.

  • 213.
    Tolstoy, Georg
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Larsson, Björn
    ABB Machines.
    Wallmark, Oskar
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Norrga, Staffan
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Elimination of vector changes due to sector changes with DTC2014In: 2014 16th European Conference on Power Electronics and Applications, EPE-ECCE Europe 2014, IEEE , 2014, p. 6910748-Conference paper (Refereed)
    Abstract [en]

    In this paper it has been investigated if there is a possibility to reduce the switching frequency for a two-level inverter by improving the direct torque control (DTC) algorithm by adding a non-switching condition when a new sector is entered. It is believed that the DTC switching table can be improved by adding a non-switching condition when sector change occurs. This will reduce the number of switching actions by up to 12 per electrical rotation without interfering with the electrical machine performance.

  • 214.
    Tolstoy, Georg
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Peftitsis, Dimosthenis
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Lim, Jang-Kwon
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Bakowski, Mietek
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Circuit Modeling of Vertical Buried-Grid SiC JFETs2010In: SILICON CARBIDE AND RELATED MATERIALS 2009, PTS 1 AND 2   / [ed] Bauer AJ; Friedrichs P; Krieger M; Pensl G; Rupp R; Seyller T, 2010, Vol. 645-648, p. 965-968Conference paper (Refereed)
    Abstract [en]

    The main problem when the conventional PSpice JFET model is used to simulate a vertical short-channel buried-grid JFET is caused by the constant values of Threshold Voltage (VTO) and Transconductance (BETA). This paper presents a new model for the vertical short-channel buried-grid 1200V JEET, where both VTO and BETA vary with respect to the Drain-Source voltage. Simulation data from Medici have been analyzed in order to extract the analytical equations for VTO and BETA. Also other PSpice parameters are extracted from these data. The proposed circuit model has been simulated in Matlab by optimizing the same algorithm that PSpice uses. A variety of results are shown and discussed in this paper.

  • 215.
    Tolstoy, Georg
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Peftitsis, Dimosthenis
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Rabkowski, Jacek
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Performance tests of a 4, 1x4, 1mm(2) SiC LCVJFET for a DC/DC boost converter application2011In: SILICON CARBIDE AND RELATED MATERIALS 2010 / [ed] Monakhov EV; Hornos T; Svensson BG, 2011, Vol. 679-680, p. 722-725Conference paper (Refereed)
    Abstract [en]

    A 4.1x4.1mm(2), 100m Omega 1,2kV lateral channel vertical junction field effect transistor (LCVJFET) built in silicon carbide (SiC) from SiCED, to use as the active switch component in a high-temperature operation DC/DC-boost converter, has been investigated. The switching loss for room temperature (RT) and on-state resistance (Ron) for RT up to 170 degrees C is investigated. Since the SiC VJFET has a buried body diode it is also ideal to use instead of a switch and diode setup. The voltage drop over the body diode decreases slightly with a higher temperature. A short-circuit test has also been conducted, which shows a high ruggedness.

  • 216.
    Tolstoy, Georg
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Peftitsis, Dimosthenis
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Rabkowski, Jacek
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Palmer, P. R.
    A discretized proportional base driver for Silicon Carbide Bipolar Junction Transistors2013In: 2013 IEEE ECCE Asia Downunder - 5th IEEE Annual International Energy Conversion Congress and Exhibition, IEEE ECCE Asia 2013, IEEE , 2013, p. 728-735Conference paper (Refereed)
    Abstract [en]

    Silicon Carbide Bipolar Junction Transistors require a continuous base current in the on-state. This base current is usually made constant and is corresponding to the maximum collector current and maximum junction temperature that is foreseen in a certain application. In this paper, a discretized proportional base driver is proposed which will reduce, for the right application, the steady-state power consumption of the base driver. The operation of the proposed base driver has been verified experimentally, driving a 1200V/40A SiC BJT in a DC-DC boost converter. In order to determine the potential reduction of the power consumption of the base driver, a case with a dc-dc converter in an ideal electric vehicle driving the new European drive cycle has been investigated. It is found that the steady-state power consumption of the base driver can be reduced by approximately 63 %. The total reduction of the driver consumption is 2816 J during the drive cycle, which is slightly more than the total on-state losses for the SiC BJTs used in the converter.

  • 217.
    Tolstoy, Georg
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Peftitsis, Dimosthenis
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Rabkowski, Jacek
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Palmer, Patrick R.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    A Discretized Proportional Base Driver for Silicon Carbide Bipolar Junction Transistors2014In: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107, Vol. 29, no 5, p. 2408-2417Article in journal (Refereed)
    Abstract [en]

    Silicon carbide (SiC) bipolar junction transistors (BJTs) require a continuous base current in the on-state. This base current is usually made constant and is corresponding to the maximum collector current and maximum junction temperature that is foreseen in a certain application. In this paper, a discretized proportional base driver is proposed which will reduce, for the right application, the steady-state power consumption of the base driver. The operation of the proposed base driver has been verified experimentally, driving a 1200-V/40-A SiC BJT in a dc-dc boost converter. In order to determine the potential reduction of the power consumption of the base driver, a case with a dc-dc converter in an ideal electric vehicle driving the new European drive cycle has been investigated. It is found that the steady-state power consumption of the base driver can be reduced by approximately 60%. The total reduction of the driver consumption is 3459 J during the drive cycle, which is slightly more than the total on-state losses for the SiC BJTs used in the converter.

  • 218.
    Tolstoy, Georg
    et al.
    KTH.
    Ranstad, P.
    Colmenares, Juan
    KTH.
    Giezendanner, F.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Dual control used in series-loaded resonant converter with SiC devices2015In: Power Electronics and ECCE Asia (ICPE-ECCE Asia), 2015 9th International Conference on, IEEE , 2015, p. 495-501Conference paper (Refereed)
    Abstract [en]

    This paper presents the performance of silicon carbide (SiC) switches in a series-loaded resonant (SLR) converter with dual control (DuC). It is shown that the SiC metal oxide-semiconductor field-effect transistor (MOSFET) with DuC increases the overall efficiency of the SLR converter compared to frequency modulation (FM). For the SiC bipolar junction transistors (BJT), the loss reduction with DuC instead of FM is not as dramatic as for the MOSFET case. Regardless of which transistor type used, the switching losses are around 20 % of the total losses at around 25 kHz. With DuC an almost constant switching frequency is used over the full voltage range compared to FM were the switching frequency increases by 13 %. Additionally a reduction of capacitive snubbers is achieved with DuC.

  • 219.
    Tolstoy, Georg
    et al.
    KTH.
    Ranstad, P.
    Colmenares, Juan
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Giezendanner, F.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Experimental evaluation of SiC BJTs and SiC MOSFETs in a series-loaded resonant converter2015In: Power Electronics and Applications (EPE’15 ECCE-Europe), 2015 17th European Conference on, IEEE , 2015, p. 1-9Conference paper (Refereed)
    Abstract [en]

    SiC devices such as MOSFETs and BJTs have proven themselves to be contenders to improve the efficiency of resonant converters. The losses of the full-bridge inverter are well below 1% of the rated power at switching frequencies up to 200 kHz, making it possible to reach even higher frequencies. An experimental setup is built and two different full-bridge inverters are tested. One is built with SiC MOSFETs and no additional anti-parallel diodes and one with SiC BJTs and SiC Schottky diodes.

  • 220.
    Tolstoy, Georg
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Ranstad, Per
    Colmenares, Juan
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Giezendanner, Florian
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Dual control used in series-loaded resonant converter with SiC devicesManuscript (preprint) (Other academic)
  • 221.
    Tolstoy, Georg
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Ranstad, Per
    Colmenares, Juan
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Giezendanner, Florian
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Experimental evaluation of SiC BJT and SiC MOSFET in a series resonantconverterManuscript (preprint) (Other academic)
  • 222.
    Tolstoy, Georg
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Ranstad, Per
    Colmenares, Juan
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Giezendanner, Florian
    Rabkowski, Jacek
    Warsaw University of Technology, Poland.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    An experimental analysis on how the dead-time of SiC BJT and SiC MOSFET impacts the losses in a high-frequency resonant converter2014In: 2014 16th European Conference on Power Electronics and Applications, EPE-ECCE Europe 2014, IEEE conference proceedings, 2014, p. 6911042-Conference paper (Refereed)
    Abstract [en]

    Active control of the dead-time in a SLR converter is in this paper shown to be of great importance. The efficiency of the full-bridge will increase if the dead-time control is made in the right way. Different control algorithms are shown to work well for different power switches. For the SiC MOSFET and the SiC BJT the control algorithms are tested experimentally.

  • 223.
    Tolstoy, Georg
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Ranstad, Per
    Colmenares, Juan
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Peftitsis, Dimosthenis
    Giezendanner, Florian
    Rabkowski, Jacek
    Warsaw University of Technology, Poland.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    An experimental analysis on how the dead-time of SiC BJT and SiC MOSFET impacts the losses in a high-frequency resonant converterManuscript (preprint) (Other academic)
  • 224.
    Tolstoy, Georg
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Wallmark, Oskar
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Norrga, Staffan
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Larsson, B.
    Elimination of vector changes due to sector changes with DTC*2015In: EPE Journal: European Power Electronics and Drives Journal, ISSN 0939-8368, Vol. 25, no 4, p. 11-16Article in journal (Refereed)
    Abstract [en]

    In this paper it has been investigated if there is a possibility to reduce the switching frequency for a two-level inverter by improving the direct torque control (DTC) algorithm by adding a non-switching condition when a new sector is entered. It is believed that the DTC switching table can be improved by adding a non-switching condition when sector change occurs. This will reduce the number of switching actions by up to 12 per electrical rotation without interfering with the electrical machine performance.

  • 225.
    Toth-Pal, Zsolt
    et al.
    Swerea-Kimab.
    Hammam, Tag
    Swerea-Kimab.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Pressure dependence of thermal contact resistance between copper heat sink and copper DBC surfaces in SiC power device packages2014In: Silicon Carbide and Related Materials 2013, Trans Tech Publications Inc., 2014, p. 1118-1121Conference paper (Refereed)
    Abstract [en]

    Thermal contact resistances have been measured in an experiment emulating heat transfer from a SiC die to a cooled heat sink through a heat spreader and a DBC structure. The major surface-dependent parameters are the surface roughness, surface hardness, and planarity. The measured thermal contact resistances are in agreement with theoretical values. When investigating DBC copper surfaces a second interface between the bonded Cu to AlN has to be taken into account.

  • 226.
    Toth-Pal, Zsolt
    et al.
    Swerea KIMAB, Sweden.
    Zhang, Yafan
    Acreo Swedish ICT, Sweden.
    Belov, I.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Bakowski, M.
    Investigation of pressure dependent thermal contact resistance between silver metallized SiC chip and DBC substrate2015In: European Conference on Silicon Carbide and Related Materials, ECSCRM 2014, Trans Tech Publications Inc., 2015, Vol. 821-823, p. 452-455Conference paper (Refereed)
    Abstract [en]

    Thermal contact resistances between a silver metallized SiC chip and a direct bonded copper (DBC) substrate have been measured in a heat transfer experiment. A novel experimental method to separate thermal contact resistances in multilayer heat transfer path has been demonstrated. The experimental results have been compared both with analytical calculations and with 3D computational fluid dynamics (CFD) simulation results. A simplified CFD model of the experimental setup has been validated. The results show significant pressure dependence of the thermal contact resistance but also a pressure independent part.

  • 227. Toth-Pal, Zsolt
    et al.
    Zhang, Yafan
    Hammam, Tag
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Bakowski, Mietek
    Thermal improvement of Press-Pack Packages: Pressure Dependent Thermal Contact Resistance with a thin Silver Interlayer between Molybdenum substrate and Silicon Carbide chip2017In: 2017 IEEE INTERNATIONAL WORKSHOP ON INTEGRATED POWER PACKAGING (IWIPP)Article in journal (Refereed)
    Abstract [en]

    In typical press-pack, free-floating packages the thermal contact resistance between chip and substrate is a major limiting factor for the cooling ability of the power module. We report an introduction of a new, thin Silver interlayer between Molybdenum substrate and chip, and how it improves the thermal contact. The thermal contact resistances were measured with and without a Silver interlayer at different pressures. The surface roughness of the SiC chip and the Molybdenum substrate were characterized. The thermal contact resistances were measured at three different heating power levels. The results show a significant reduction of the thermal contact resistance with only a few micrometer Silver interlayer. The improved cooling effect of a Silver interlayer was also demonstrated with a fluid dynamics type of 3 D simulation comparing temperature distributions with and without a Silver interlayer. These results project a possible thermal improvement in press-pack packages.

  • 228.
    Toth-Pal, Zsolt
    et al.
    Swerea KIMAB, Sweden.
    Zhang, Yafan
    Swerea KIMAB, Sweden.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Bakowski, M.
    Investigation of pressure dependent thermal contact resistance between silver metallized SiC chip and molybdenum substrate and between molybdenum substrate and bulk copper2016In: 16th International Conference on Silicon Carbide and Related Materials, ICSCRM 2015, Trans Tech Publications, 2016, Vol. 858, p. 1061-1065Conference paper (Refereed)
    Abstract [en]

    Thermal contact resistances between a silver metallized SiC chip and a Molybdenum substrate and between the Molybdenum substrate and bulk Copper were measured in a heat transfer experiment. An experimental method to separate thermal contact resistances in a multilayer heat transfer path was used to extract the layer-specific contact resistances. The experimental results were compared with theory based calculations and also with 3-D computational fluid dynamics (CFD) simulation results. The results show significant pressure dependence of the thermal contact resistance and the results show higher thermal contact resistance per unit area between the bulk SiC chip and Molybdenum than between Molybdenum and bulk Copper.

  • 229. Velander, E.
    et al.
    Kruse, L.
    Meier, S.
    Lofgren, A.
    Wiik, T.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Sadik, Diane-Perle
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Analysis of short circuit type II and III of high voltage SiC MOSFETs with fast current source gate drive principle2016In: 2016 IEEE 8th International Power Electronics and Motion Control Conference, IPEMC-ECCE Asia 2016, Institute of Electrical and Electronics Engineers (IEEE), 2016, p. 3392-3397, article id 7512839Conference paper (Refereed)
    Abstract [en]

    The Silicon Carbide (SiC) MOSFET is considered to be the leading candidate for future 1.7 kV and 3.3 kV switches in 2-level voltage source converters (VSC) up to 2 MW. For those converters, short circuit (SC) in the dc-link loop can occur due to a number of reasons, e.g. faulty semiconductor modules, faulty gate drivers (GDs), or electro-magnetic interference (EMI). Termination of such SCs is important in order to protect components and reduce the damage in the converter box. This paper presents a new short circuit protection scheme based on a universal current-source GD principle without dedicated hardware components. The performance of the design is evaluated for SC in the dc-link loop under load conditions, called type II and type III. Moreover, measurement results are presented using the proposed GD connected to a 1700 V 300 A SiC MOSFET tested during SC type II and III at two different dc-link stray inductances, 30 nH and 100 nH, and at two different temperatures, 25 °C and 125 °C. The conclusions are that the proposed scheme is able to terminate both SC type II and III with fast reaction time, with low energy dissipation, with a margin of about 15 times below the destructive level for dc-link voltages and load currents up to 1050 V and 300 A respectively.

  • 230.
    Velander, Erik
    et al.
    Bombardier Transportat Sweden AB, Dept Medium Power Tract Converter Design, S-72173 Vasteras, Sweden..
    Bohlin, Georg
    Bombardier Transportat Sweden AB, Tract Syst Dept, S-72173 Vasteras, Sweden..
    Sandberg, Asa
    Bombardier Transportat Sweden AB, Tract Syst Dept, S-72173 Vasteras, Sweden..
    Wiik, Thomas
    Bombardier Transportat Sweden AB, Dept Medium Power Tract Converter Design, S-72173 Vasteras, Sweden..
    Botling, Fredrik
    Bombardier Transportat Sweden AB, Dept Converter Control, S-72173 Vasteras, Sweden..
    Lindahl, Martin
    Bombardier Transportat Sweden AB, Dept Medium Power Tract Converter Design, S-72173 Vasteras, Sweden..
    Zanuso, Giovanni
    KTH, School of Electrical Engineering and Computer Science (EECS), Electric Power and Energy Systems.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering and Computer Science (EECS), Electric Power and Energy Systems.
    An Ultralow Loss Inductorless dv/dt Filter Concept for Medium-Power Voltage Source Motor Drive Converters With SiC Devices2018In: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107, Vol. 33, no 7, p. 6072-6081Article in journal (Refereed)
    Abstract [en]

    In this paper, a novel dv/dt filter is presented targeted for 100-kW to 1-MW voltage source converters using silicon carbide (SiC) power devices. This concept uses the stray inductance between the power device and the converter output as a filter component in combination with an additional small RC-link. Hence, a lossy, bulky, and costly filter inductor is avoided and the resulting output dv/dt is limited to 5-10 kV/mu s independent of the output current and switching speed of the SiC devices. As a consequence, loads with dv/dt constraints, e.g., motor drives can be fed from SiC devices enabling full utilization of their high switching speed. Moreover, a filter-model is proposed for the selection of filter component values for a certain dv/dt requirement. Finally, results are shown using a 300-A 1700-V SiC metal-oxide-semiconductor field-effect transistor (MOSFET). These results show that the converter output dv/dt can be limited to 7.5 kV/mu s even though values up to 47 kV/mu s weremeasured across the SiC MOSFET module. Hence, the total switching losses, including the filter losses, are verified to be three times lower compared to when the MOSFET dv/dt was slowed down by adjusting the gate driver.

  • 231.
    Velander, Erik
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems. Bombardier Transportation Sweden AB.
    Bohlin, Georg
    Sandberg, Åsa
    Wiik, Thomas
    Lindahl, Martin
    Botling, Fredrik
    Zanuso, Giovanni
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    An Ultra-Low Loss Inductorless dv/dt Filter Concept for Medium Power Voltage Source Motor Drive Converters with SiC DevicesIn: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107Article in journal (Refereed)
  • 232. Velander, Erik
    et al.
    Kruse, Lennart ( Zdansky)
    Wiik, Thomas (Lundstrom)
    Wiberg, Anders
    Colmenares, Juan
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    An IGBT Turn-ON Concept Offering Low Losses Under Motor Drive dv/dt Constraints Based on Diode Current Adaption2018In: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107, Vol. 33, no 2, p. 1143-1153Article in journal (Refereed)
    Abstract [en]

    In this paper, a new low-loss turn-ON concept for the silicon insulated-gate bipolar transistor (Si-IGBT) in combination with silicon p-i-n diode is presented. The concept is tailored for two-level motor converters in the 100 kW to 1 MW range under the constraint that the output voltages slopes are limited in order to protect the motor windings. Moreover, analyses of the IGBT turn-ON and diode reverse recovery voltage slopes are presented concluding that the diode reverse recovery is the worst case. The concept includes a low-cost measurement of the free-wheeling diode current and temperature by the gate driver without necessity of acquiring this information from the converter control board. By using this concept, the output dv/dt at the diode turn-OFF can be kept approximately constant regardless of the commutated current and junction temperature. Hence, the switching losses could be decreased for the currents and temperatures where the voltage slopes are lower when using a conventional gate driver optimized for the worst case. Moreover, results are shown for one such power semiconductor, showing a total switching loss reduction of up to 28% in comparison with a gate driver without current and temperature measurement. Finally, this concept is particularly suitable for high power semiconductor modules in half-bridge configuration which are recently proposed by several suppliers.

  • 233.
    Velander, Erik
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems. Bombardier Transportation Sweden AB.
    Kruse, Lennart
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Optimal Switching of SiC Lateral MOSFET2015Conference paper (Other academic)
  • 234. Velander, Erik
    et al.
    Kruse, Lennart
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Optimal switching of SiC lateral MOSFETs2015In: Power Electronics and Applications (EPE’15 ECCE-Europe), 2015 17th European Conference on, IEEE , 2015, p. 1-10Conference paper (Refereed)
    Abstract [en]

    The switching loss of the 1700 V SiC Planar-Gate MOSFET is significant at switching frequencies above 2 kHz. If a simple resistive gate driver is adjusted for the worst case operating point (temperature, commutated voltage and current) with a given application dV/dt requirement, other operating points usually have lower dV/dt resulting in non-optimal losses. The paper shows results of an optimized gate-drive solution, adapting a current source control in order to reduce the losses while fulfilling the application dV/dt requirements.

  • 235.
    Velander, Erik
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems. Bombardier Transportation Sweden AB.
    Kruse, Lennart
    Wiik, Thomas
    Wiberg, Anders
    Colmenares, Juan
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    An IGBT Turn-ON Concept Offering Low Losses Under Motor Drive dv/dt Constraints Based on Diode Current AdaptionIn: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107Article in journal (Refereed)
  • 236.
    Velander, Erik
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems. Bombardier Transportation Sweden AB.
    Löfgren, Andreas
    Kretschmar, Karsten
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Novel Solutions for suppressing Parasitic Turn-on behaviour on Lateral Vertical JFETs2014In: Novel Solutions for suppressing Parasitic Turn-on behaviour on Lateral Vertical JFETs, Lappeenranta, 2014, p. 8-Conference paper (Other academic)
  • 237.
    Xie, Hailian
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Ängquist, Lennart
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    A Converter Topology Suitable for Interfacing Energy Storage with the dc Link of a StatCom2008In: 2008 IEEE INDUSTRY APPLICATIONS SOCIETY ANNUAL MEETING, 2008, p. 1916-1919Conference paper (Refereed)
    Abstract [en]

    Voltage Source Converters (VSC) have been widely utilized to provide instantaneous reactive power support to power systems, an application referred to as Static synchronous Compensators (StatCom). Integration of energy storage (ES) into a StatCom makes it possible for the StatCom to provide a certain amount of active power as well as reactive power support. The possible benefit of the additional active power support of a StatCom can be power oscillation damping capability, mitigation of phase-jump related disturbance, etc. Direct connection of ES device to the dc link of the VSC incurs unnecessary high voltage rating of the VSC due to the considerable voltage swing associated with the ES device. This paper proposes a thyristor converter topology as the interface between the ES device and the VSC dc link. With the proposed interface, the dc voltage of the VSC can be kept constant and thus lower the VSC rating and cost.

  • 238.
    Xie, Hailian
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Ängquist, Lennart
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Active power compensation of voltage source converters with energy storage capacitors2006In: 2006 IEEE/PES POWER SYSTEMS CONFERENCE AND EXPOSITION. VOLS 1-5, NEW YORK: IEEE , 2006, p. 1012-1019Conference paper (Refereed)
    Abstract [en]

    The voltage at the point of common coupling (PCC) in a weak network is very sensitive to load changes. A sudden change in active load will cause both a phase jump and a magnitude fluctuation in the bus voltage, whereas reactive load changes mainly affect the voltage magnitude. With the addition of energy storage to a static synchronous compensator (StatCom), it is possible to compensate for the active power change as well as providing reactive power support. In this paper some effective active power compensation schemes are proposed. Simulation and experimental results verify the compensation schemes by showing that a StatCom with energy storage can significantly reduce phase jumps and magnitude deviations of the bus voltage. Simulation results are also presented showing the benefits of active power compensation to certain applications with phase sensitive load.

  • 239. Xie, Hailian
    et al.
    Ängquist, Lennart
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics (closed 20110930).
    Nee, Hans-Peter
    Comparison of Voltage and Flux Modulation Schemes of StatComs Regarding Transformer Saturation During Fault Recovery2008In: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679, Vol. 23, no 4, p. 1653-1661Article in journal (Refereed)
    Abstract [en]

    A transformer might be driven into saturation by faults in the connected system. In a transmission system with a Static synchronous Compensator and transformers connected at the point of common coupling, different modulation schemes utilized by the voltage source converter influence the transformer saturation in different ways. This paper compares the saturation effect during fault recovery when two alternative modulation schemes are utilized: voltage modulation and flux modulation. The comparison shows that utilization of flux modulation scheme. tends to soften the saturation problem during fault recovery. However, this is achieved at a higher converter transient peak current.

  • 240.
    Xie, Hailian
    et al.
    KTH, School of Electrical Engineering (EES).
    Ängquist, Lennart
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Design and Analysis of a Controller for a Converter Interface Interconnecting an Energy Storage With the Dc Link of a VSC2010In: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679, Vol. 25, no 2, p. 1007-1015Article in journal (Refereed)
    Abstract [en]

    Voltage source converters (VSC) have been widely utilized to provide instantaneous reactive power support to power systems, an application referred to as static synchronous compensator (StatCom). Integration of energy storage (ES) into a StatCom makes it possible for the StatCom to provide a certain amount of active power as well as reactive power support. The possible benefit of the additional active power support of a StatCom can be power oscillation damping capability, mitigation of phase-jump related disturbances, etc. Direct connection of an ES device to the dc link of the VSC incurs unnecessarily high voltage rating of the VSC due to the considerable voltage swing associated with the ES device. In order to reduce the total cost, a dual thyristor converter topology has been proposed as the interface between the ES and the dc link of the VSC. In this paper, dynamics of the proposed system are investigated. Control strategies are proposed and verified by simulations with PSCAD/EMTDC.

  • 241.
    Xie, Hailian
    et al.
    ABB Corporate Research, Beijing.
    Ängquist, Lennart
    KTH, School of Electrical Engineering (EES).
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES).
    Design study of a converter interface interconnecting an energy storage with the dc-link of a VSC2010In: 2010 IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT Europe), 2010Conference paper (Refereed)
    Abstract [en]

    Voltage Source Converters (VSC) have been widely utilized to provide instantaneous reactive power support to power systems, an application referred to as static synchronous compensator (StatCom). Integration of energy storage (ES) into a StatCom makes it possible for the StatCom to provide a certain amount of active power as well as reactive power support. The possible benefit of the additional active power of a StatCom can be power oscillation damping capability, mitigation of phase-jump related disturbances, etc. Direct connection of an ES device to the dc link of the VSC incurs unnecessarily high voltage rating of the VSC due to the considerable voltage swing associated with the ES device. A dual thyristor converter topology has been proposed as the interface between the ES and the dc link of the VSC. In this paper, a cost estimation for systems with the proposed interface topology is presented regarding three types of ES: capacitors, supercapacitors, and batteries. The study shows potential cost savings by utilization of the proposed interface topology. In addition, a cost comparison between different types of ES is presented, providing a guideline for the choice of ES in this kind of applications.

  • 242.
    Xie, Hailian
    et al.
    ABB Corporate Research, Beijing, China.
    Ängquist, Lennart
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Design Study of a Converter Interface Interconnecting Energy Storage With the DC Link of a StatCom2011In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 26, no 4, p. 2676-2686Article in journal (Refereed)
    Abstract [en]

    Voltage-source converters (VSC) have been widelyutilized to provide instantaneous reactive power support topower systems, an application referred to as static synchronouscompensator (StatCom). The integration of energy storage (ES)into a StatCom makes it possible for the StatCom to provide acertain amount of active power as well as reactive power support.The possible benefit of the additional active power of aStatCom can be power oscillation damping capability, mitigationof phase-jump-related disturbances, etc. Direct connection ofan ES device to the dc link of the VSC incurs an unnecessarilyhigh-voltage rating of the VSC due to the considerable voltageswing associated with the ES device. Dual thyristor convertertopology has been proposed as the interface between the ES andthe dc link of the VSC. In this paper, a cost estimation for systemswith the proposed interface topology is presented regarding threetypes of ES: capacitors, supercapacitors, and batteries. The studyshows potential cost savings with utilization of the proposed interfacetopology. In addition, a cost comparison between differenttypes of ES is presented, providing a guideline for the choice of ES in these kinds of applications.

  • 243.
    Xie, Hailian
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics (closed 20110930).
    Ängquist, Lennart
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics (closed 20110930).
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics (closed 20110930).
    Impact of energy storage on system performance under fault conditions2007In: International CIGRE Zagreb Symposium 2007: Transient Phenomena in Large Electric Power Systems, 2007Conference paper (Refereed)
    Abstract [en]

    This work investigates the impact of the energy stored in the dc side capacitor of a converter on the system performance under fault conditions. The system under investigation consists of two interconnected sources feeding a radial string of heavily loaded transmission lines. Along the lines six large induction motors are connected together with eight other loads and some capacitor banks supplying the reactive power consumption in the motors and lines. Since the system is vulnerable to faults close to the sources, additional reactive power support is necessary to improve the fault ride-through capability of the system and the performance of the motors. During a fault, the motor terminal voltage is very low. The unbalance between the electrical torque and the mechanical torque decelerates the motor. After the fault-clearance, the motor starts to accelerate if the electrical torque generated is larger than the mechanical torque. In order to produce the required torque, the motor consumes much more reactive power than under normal condition. If the reactive power support is not sufficient, the motor will keep decelerating until it stops. A StatCom can be installed to provide fast and dynamic reactive power support and voltage control to the system. In this paper, a control scheme for a StatCom with energy storage capability is proposed. The system performance, especially the motor speeds, will be analyzed through simulations carried out in PSCAD. It is shown in the paper that the scheme with active power compensation effectively helps the system to recover from faults. Although this incurs extra cost for the increased dc voltage of the converter and the dc side capacitor, the overall rating of the converter can be reduced by utilization of the proposed scheme.

  • 244.
    Xie, Hailian
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Ängquist, Lennart
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics.
    Investigation of StatComs With Capacitive Energy Storage for Reduction of Voltage Phase Jumps in Weak Networks2009In: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679, Vol. 24, no 1, p. 217-225Article in journal (Refereed)
    Abstract [en]

    The voltage at the point of common coupling (PCC) in a weak network is very sensitive to load changes. A sudden change in active load will cause both a phase jump and a magnitude fluctuation in the bus voltage (voltage at the PCC), whereas reactive load changes mainly affect the voltage magnitude. With the addition of energy storage to a static synchronous compensator (StatCom), it is possible to compensate for the active power change as well as providing reactive power support. In this paper effective active power compensation schemes are proposed. Simulation and experimental results verify the compensation schemes by showing that a StatCom with energy storage can significantly reduce phase jumps and magnitude deviations of the bus voltage under load disturbances.

  • 245.
    Xie, Hailian
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics (closed 20110930).
    Ängquist, Lennart
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics (closed 20110930).
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics (closed 20110930).
    Investigation of the Control of a Converter Topology Interfacing an Energy Storage with the dc Link of a VSC2009In: 2009 13th European Conference on Power Electronics and Applications, EPE '09, IEEE , 2009, p. 5289-5298Conference paper (Refereed)
    Abstract [en]

    Integration of energy storage (ES) into a static synchronous compensator (StatCom) makes it possible for the StatCom to provide a certain amount of active power as well as reactive power support. The possible benefit of the additional active power support of a StatCom can be power oscillation damping capability, mitigation of phase-jump related disturbances, etc. Direct connection of an ES device to the dc link of the VSC incurs high voltage rating of the VSC due to the considerable voltage swing associated with the ES device. In order to reduce the total cost, a dual thyristor converter topology has been proposed as the interface between the ES and the dc link of the voltage Source Converter. In this paper, the dynamics of the proposed system are investigated. Control strategies are proposed and verified by simulations with PSCAD/EMTDC. A comparison is made between two control methods.

  • 246.
    Xie, Hailian
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics (closed 20110930).
    Ängquist, Lennart
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics (closed 20110930).
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Machines and Power Electronics (closed 20110930).
    Novel flux modulated positive and negative sequence deadbeat current control of voltage source converters2006In: IEEE POWER ENG SOC GEN MEETIN, 2006, p. 533-540Conference paper (Refereed)
    Abstract [en]

    Voltage source converters are widely used in the power system to enhance the power system performance. In the conventional converter control, the control system usually takes the voltage measured at the point where the converter is connected and calculates the reference voltage for the converter; with a modulation system the converter then produces the required 'average voltage'. In this paper, a novel flux modulation scheme, combined with the deadbeat current control strategy, is proposed. The current controller is capable of controlling both positive and negative sequence currents. With flux modulation, the control system measures the bus flux and commands the converter to generate the required flux. The simulation and experimental results presented show a good performance of this converter control system.

  • 247.
    Xie, Hailian
    et al.
    KTH, School of Electrical Engineering (EES).
    Ängquist, Lennart
    KTH, School of Electrical Engineering (EES).
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES).
    StatCom with Capacitive Energy Storage for Compensation of Cyclic Loads2008In: Proceedings of the Nordic Workshop on Power and Industrial Electronics (NORpie) 2008, 2008Conference paper (Refereed)
    Abstract [en]

    Pulsating power consumption of a cyclic load may cause considerable disturbances in the voltage at the connection point. A StatCom can be employed to maintain the bus voltage level. With the integration of energy storage to the StatCom, the power quality at the connection point can be further improved by the additional active power compensation capability. This paper studies the control strategy for a StatCom with capacitive energy storage for compensation of a cyclic load. Simulations verify the proposed control scheme and show that both the phase jump and magnitude deviation of the bus voltage can be reduced by means of reactive and active power compensation.

  • 248.
    Zdanowski, M.
    et al.
    Warsaw Univ Technol, Inst Control & Ind Elect, Warsaw, Poland..
    Rabkowski, Jacek
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Kostov, Konstantin
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Barlik, R.
    Warsaw Univ Technol, Inst Control & Ind Elect, Warsaw, Poland..
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Design and Evaluation of Reduced Self-Capacitance Inductor for Fast-Switching SiC BJT dc/dc Converters2012In: 2012 15TH INTERNATIONAL POWER ELECTRONICS AND MOTION CONTROL CONFERENCE (EPE/PEMC), IEEE , 2012Conference paper (Refereed)
    Abstract [en]

    The paper presents design, measurements and evaluation of the inductor with reduced self-capacitance. As an reference inductor with the same parameters but non-optimized self-capacitance is chosen. Differences in the parasitic capacitance of the inductor are validated by four measurement methods and experimentally confirmed on a 2 kW, 100 kHz dc/dc converter with silicon carbide BJTs. When the low-capacitance inductor is applied the switching performance is better, especially high-frequency resonances are limited. Additionally, it was found that the power losses were reduced by approximately 20%.

  • 249. Zdanowski, Mariusz
    et al.
    Kostov, Konstantin
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Rabkowski, Jacek
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Barlik, Roman
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Design and Evaluation of Reduced Self-Capacitance Inductor in DC/DC Converters with Fast-Switching SiC Transistors2014In: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107, Vol. 29, no 5, p. 2492-2499Article in journal (Refereed)
    Abstract [en]

    The paper presents an inductor with reduced self-capacitance, designed and evaluated with fast-switching SiC transistors in dc-dc converters. A conventional inductor with the same core and number of turns was also build for comparison. The two inductors are tested experimentally on two different 2 kW, 100 kHz dc-dc converters with silicon carbide switches-one with a junction field-effect transistor (JFET) and the other with a bipolar junction transistor (BJT). Replacing the conventional inductor with the one that has lower self-capacitance improved the switching performance of the converter and reduced its electromagnetic emissions. Furthermore, the efficiency of the converter is improved-in the case of the JFET boost converter the power losses were reduced by 16% and by 20% in the case of BJT.

  • 250.
    Zdanowski, Mariusz
    et al.
    Warsaw University of Technlogy.
    Rabkowski, Jacek
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Kostov, Konstantin
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Barlik, R.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Design and Evaluation of Reduced Self-Capacitance Inductor for Fast-Switching SiC BJTdc/dc Converters2012In: Power Electronics and Motion Control Conference (EPE/PEMC), 2012 15th International, IEEE , 2012, p. DS1a.41-DS1a.47Conference paper (Refereed)
    Abstract [en]

    The paper presents design, measurements and evaluation of the inductor with reduced self-capacitance. As an reference inductor with the same parameters but non-optimized self-capacitance is chosen. Differences in the parasitic capacitance of the inductor are validated by four measurement methods and experimentally confirmed on a 2 kW, 100 kHz dc/dc converter with silicon carbide BJTs. When the low-capacitance inductor is applied the switching performance is better, especially high-frequency resonances are limited. Additionally, it was found that the power losses were reduced by approximately 20%.

23456 201 - 250 of 273
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