Publications Search Results

Now showing 1 - 10 of 15
  • Publication
    Gleichstrom als Enabler der Energieflexibilisierung
    Der heutige elektrische Energiefluss im Unternehmen mit einer Wechselstromversorgung ist geprägt von einem im Wesentlichen unidirektionalen Energiefluss, beginnend beim Mittelspannungstransformator, über Stromschienen, Verteilschränke bis in die Maschine zum jeweiligen Antrieb. Dabei findet, sofern es sich um geregelte Lasten wie Antriebe handelt, bereits eine Wandlung von Wechselstrom (AC) auf Gleichstrom (DC) statt und anschließend wieder zurück auf einen in der Frequenz modellierten Wechselstrom. Diese Kette aus Wandlungsstellen in der Energieübertragung eines Fabriknetzes ist mit Verlusten behaftet.
  • Publication
    Control Design and Stability Analysis of an Energy Storage System in a DC Link for Industrial Pulsed Power Applications
    ( 2021)
    Lu, Yijun
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    Laribi, Raoul
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    ;
    This paper analyzes an energy storage system (ESS) in a direct current (DC) link to mitigate the high power ratio. Furthermore, it examines how the ESS control architecture can be modelled to coordinate the interaction among the prosumers in the DC link so that the peak shaving target is achieved. First, the paper presents a simulation model of the ESS connected to the DC link. Then, the DC link supply of passive rectifier and active infeed converter are discussed separately with measured data. The inverter control system is simplified and integrated in the software framework. Peak shaving can be achieved by droop control or power control. After that, the paper presents a system configuration with communication via OPC UA for a potential forecast control strategy and energy management. The simulation shows the potential for optimized load management with a mid-sized ESS.
  • Publication
    Grid Management
    ( 2021)
    Ott, Leopold
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    Männel, Alexander
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    Hinderer, Werner
  • Publication
    Coupling Analysis for the Design of Industrial DC Microgrids
    ( 2021)
    Schaab, Darian Andreas
    ;
    Knapp, Jonas
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    Society is chasing for a sustainable electric power supply. A successful transition requires efficient conversion of electric power and carbon neutral power generation by renewable sources. Low voltage direct current microgrids (DC MG) provide a solution in both scopes. Often a droop control is used as the control strategy for DC microgrids. Droop control is a decentralized strategy to balance power flow of multiple infeed converters. While this approach avoids communication between converters, it results in a strong coupling of all control loops in the grid. The question arises, how to select control parameters of a droop controlled DC MG with respect to coupling of all control loops. This paper investigates on a solution to this topic using direct nyquist array (DNA) design for a droop controlled DC MG. The analysis shows, that there is a high coupling in the low frequency area and in the range of network resonances. Due to some limitations, the Gershgorin method used in this paper is not suitable for controller design in strongly coupled grids. However, the new study shows the influence of various parameters on the coupling of the single control loops in the grid as well as on the stability. The question remains, how to proof stability with respect to interaction at these frequencies.
  • Publication
    Unterwegs zur Gleichstromfabrik: Der Transformationsprozess im industriellen Stromnetz
    Die zukünftige Stromversorgung einer Fabrik soll Energie effizient, sicher und robust bereitstellen. Das industrielle DC-Smart-Grid verfügt über das technologische Potenzial, dieses Ziel zu erreichen. Jedoch erfordert dies eine grundlegende und umfassende Transformation des Energiesystems in der Fabrik. Der vorliegende Beitrag stellt Strategien für den technologischen Wandel vor und beschreibt diese Transformation sowie Roadmaps zur Umsetzung.
  • Publication
    Netzmanagement
    ( 2020)
    Ott, Leopold
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    ;
    Männel, Alexander
    ;
    Hinderer, Werner
  • Publication
    Stability Implications for the Design Process of an Industrial DC Microgrid
    ( 2020)
    Schaab, Darian Andreas
    ;
    The future electric grid faces challenges by a rising share of renewable generation. This development increases the number of smaller decentralized power plants and therefore the volatility of energy generation. A technical approach to overcome these challenges is to cluster distributed energy generation and local power demand in microgrids. These can be used to balance power generation and demand locally and in short time frames. The industry relies on an high quality and reliable power supply, which can be ensured in a microgrid architecture, even if the main AC power grid does not meet the requirements. In specific industrial applications prototypes of direct current (DC) microgrids are built. Such a multi terminal architecture is in need for a grid control that adjusts the respective power flow of each device. This study aims on determining the implications for the DC microgrid design process with respect to stability of the control system.
  • Publication
    Sizing Electric Storage Devices for Power Smoothing Applications in DC Microgrids
    ( 2019)
    Schaab, Darian Andreas
    ;
    Laribi, Raoul
    ;
    Converter technologies powering drive systems established direct current technology in industrial applications. Recent developments expand the regular Direct Current (DC) link from a multi-axis-drive-systems to an interlinked multiple machine supply system. The extended DC-link allows for the exchange of recuperated energy between different processes and increases the overall system efficiency. The comparison of the extended DC link and the DC microgrids shows that the integration of multiple supply systems, like distributed generation and storage systems, allows for further optimization with respect to reliability, efficiency and robustness. One possible optimization strategy is to reduce dynamic load peaks with a storage system and downsize the grid infeed converter. Several applications for power smoothing can be found in literature, however there is no approach for sizing storage capacity and power for these applications. This paper introduces a systematic approach, which aims for storage sizing based on a load profile of industrial machines.