05 Fakultät Informatik, Elektrotechnik und Informationstechnik

Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/6

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Institute: search.filters.UBSInstitut.Institut für Energieübertragung und HochspannungstechnikAuthor: search.filters.author.Köhler, Wolfgang

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Now showing 1 - 5 of 5
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    Einfluss der Abschlussimpedanz von Hochvoltkabeln auf Funkstörgrößen in elektrisch angetriebenen Kraftfahrzeugen
    (2012) Reuter, Martin; Waible, Manuel; Tenbohlen, Stefan; Köhler, Wolfgang
    In diesem Beitrag wird die Frage untersucht, welche Auswirkung die Fehlanpassung von Kfz-Hochvoltkabeln auf EMV-Störgrößen in der Komponentenmessung nach CISPR 25 hat.
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    Influence of termination impedance on conducted emissions in automotive high voltage networks
    (2012) Reuter, Martin; Tenbohlen, Stefan; Köhler, Wolfgang
    This contribution investigates the effect of changed network topologies within HV systems on component level EMC tests. Therefore the recent state of art in component level testing is presented and the differences of LV and HV network topologies are discussed. An adaption of the component level test setup for HV components is introduced and a minimized HV system investigated. Results of a case study on an inverter for a hybrid car are presented and the impact of the measurements in the design of HV systems will be discussed.
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    New mitigation methods for transient overvoltages in gas insulated substations
    (2012) Burow, Simon; Riechert, Uwe; Köhler, Wolfgang; Tenbohlen, Stefan
    During switching of disconnectors (DS) in GIS a varying number of pre-strikes and re-strikes occur. Due to the very short duration of the voltage collapse, traveling surges are generated in the busbar duct. These very fast transient overvoltages (VFTO) can become the limiting dielectric stress which defines the dimensions at UHV voltage levels. The decision shall be based on the maximum VFTO peak value that occurs with reference to the rated lightning impulse withstand voltage (LIWV) of the equipment. If the maximum VFTO is higher than the LIWV, it is necessary to consider the VFTO level as dimensioning criteria or to suppress VFTO by suitable measures. The main challenges are the reduction in VFTO amplitudes and finally the reduction of the effects of VFTO on the equipment. For the different sources of VFTO and for the different equipment different mitigation methods are known. The damping of VFTO by integration of a damping resistor is a well proven technology. The way to overcome the drawback of such unwieldy designs is to use other internal damping measures. Several methods have been proposed and examined in the past, such as ferrite material or high frequency (RF) resonators. The VFTO damping solution utilizing ferrite rings has been analysed and tested and will be described here. The measurements show that a damping effect can be achieved, but with an important drawback: the magnetic material goes easily into saturation, which complicates the design and reduces its general applicability and robustness. A new approach for damping is to implement compact electromagnetic high-frequency resonators with low quality factor specially designed to cover a wider frequency range. The novelty of this idea is not only to design the resonators but also to dissipate the VFTO energy. The VFTO damping effect of the developed RF resonator tuned to the dominant harmonic component was confirmed by experiments. Rings of a nanocrystalline alloy placed around the GIS conductor were also investigated. Depending on number, material and size of the rings a good mitigation could be achieved.
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    Impedance analysis of automotive high voltage networks for EMC measurements
    (2011) Reuter, Martin; Tenbohlen, Stefan; Köhler, Wolfgang; Ludwig, A.
    This paper deals with a method of determining the high-frequency impedances of automotive HV power networks. A Vector Network Analyzer (VNA) is used to measure Scattering parameters of different HV power cables and an automotive Li-Ion accumulator battery. Matrix conversions allow calculating an impedance network, which is able to represent an automotive HV networks.
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    Characterization of automotive high voltage networks for EMI measurements
    (2010) Reuter, Martin; Tenbohlen, Stefan; Köhler, Wolfgang
    This paper deals with a method of determining the high-frequency impedances of automotive HV power networks (300 kHz - 200 MHz). A Vector Network Analyzer (VNA) is used to measure Scattering-Parameters of different HV power cables. Matrix conversions allow calculating an impedance network, which is able to represent automotive HV networks.