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.Fakultätsübergreifend / Sonstige EinrichtungInstitute: search.filters.UBSInstitut.Institut für Elektrische Energiewandlung

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Now showing 1 - 5 of 5
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    Additively manufactured transverse flux machine components with integrated slits for loss reduction
    (2022) Kresse, Thomas; Schurr, Julian; Lanz, Maximilian; Kunert, Torsten; Schmid, Martin; Parspour, Nejila; Schneider, Gerhard; Goll, Dagmar
    Laser powder bed fusion (L-PBF) was used to produce stator half-shells of a transverse flux machine from pure iron (99.9% Fe). In order to reduce iron losses in the bulk components, radially extending slits with a nominal width of 150 and 300 µm, respectively, were integrated during manufacturing. The components were subjected to a suitable heat treatment. In addition to a microscopic examination of the slit quality, the iron losses were also measured using both a commercial and a self-developed measurement setup. The investigations showed the iron losses can be reduced by up to 49% due to the integrated slits and the heat treatment.
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    Monolithically integrated GaN power stage for more sustainable 48 V DC-DC converters
    (2024) Basler, Michael; Mönch, Stefan; Reiner, Richard; Benkhelifa, Fouad; Quay, Rüdiger
    In this article, a fully monolithically integrated GaN power stage with a half-bridge, driver, level shifter, dead time and voltage mode control for 48 V DC-DC converters is proposed and analyzed. The design of the GaN IC is presented in detail, and measurements of the single function blocks and the DC–DC converter up to 48 V are shown. Finally, considerations are given on a life cycle assessment with regard to the GaN power integration. This GaN power IC or stage demonstrates a higher level of integration, resulting in a reduced bill of materials and therefore lower climate impact.
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    A review of electromagnetic simulation and modelling approaches for the research on axial flux synchronous machines
    (2024) Schäfer, Adrian; Pecha, Urs; Parspour, Nejila; Kampker, Achim; Born, Henrik; Hartmann, Sebastian; Franke, Jörg; Baader, Marcel; Hahn, Roman
    Extensive electromagnetic (EMAG) studies are necessary to fully realize the potential of axial flux machines (AFMs). However, the disc-shaped air gap and the complex three-dimensional path of magnetic flux pose challenges in modelling AFMs compared to conventional radial flux machines. This study reviews current research on EMAG modelling and simulation of AFMs, highlighting the need for tools that address AFM-specific effects. Existing approaches are analysed based on the requirements composed by fundamental objectives of EMAG simulations and AFM-specific effects, revealing limitations in flexibility and the ability to capture emerging trends in the field of AFMs. While computationally expensive 3D finite element analysis (FEA) offers comprehensive flexibility in EMAG modelling, it lacks efficiency to carry out extensive studies on such trends. Therefore, there is a need to either further accelerate 3D FEA or to increase the flexibility of existing alternatives to facilitate and thereby promote research in the field of AFM and other 3D flux machines. While the integration of some production-specific effects, such as manufacturing tolerances, already is investigated for EMAG simulations of AFMs the future research on the early estimation of manufacturability based on EMAG simulations is crucial for evaluating designs and anticipating manufacturing influences.
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    Optimal transistor dimensioning in T-type topology for reduced quasi-2-level switching loss
    (2025) Söllner, Adrian; Jie, Chengcong; Mönch, Stefan
    A quasi-2-level switching T-type topology reduces hard-switching loss compared to half-bridges, but requires more semiconductor area. This work shows that the middle transistor can be dimensioned smaller than the high/low-side transistors, which further reduces both the switch node capacitance and switching loss. The paper also presents a scalable transistor model, which is used in simulations of inductive-load hard-switching to determine switching losses and reveal a loss-optimal transistor dimensioning. Furthermore a double pulse setup (600 V-rated GaN HEMTs in a T-type topology) with 2 ground referenced shunts is proposed to determine switching energy of middle and low side transistors simultaneously. To verify the concept of loss-optimal transistor dimensioning in Q2L T-type topology, switching energy was measured at 200 V and 1 A, with the middle transistors area reduced by half compared to high/low side, resulting in a measured reduction from 4.44 µJ to 2.18 µJ (-51%) which is similar to the simulated reduction (2.39 µJ to 1.43 µJ, -40%). This method allows reduction of Q2L switching-loss with optimal transistor area and can be used for a wide range of applications.
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    Magnetic measurements of a stator core under manufacturing influences and the impacts on the design process of a reluctance synchronous machine
    (2025) Regnet, Martin; Schmidt, Michael; Valencia Pérez, Alejandro; Löhlein, Bernd; Reinlein, Michael; Dietz, Armin; Germishuizen, Johannes; Parspour, Nejila
    The magnetic properties of electrical steel sheets, crucial for efficient electrical machine performance, deteriorate through manufacturing processes. This study investigates the impact of different manufacturing steps on magnetization behavior and specific core losses in M270-50A electrical steel, and their influence on the performance of a reluctance synchronous machine (RSM). Magnetic measurements were conducted on three material states: laser-cut strips, assembled stator cores, and press-fitted stator cores. These were integrated into finite element analysis (FEA) models, including an extended two-region stator model that separates yoke and tooth regions to reflect different manufacturing effects. Simulations examined torque characteristics and flux linkage under various loading conditions and were validated using a prototype machine. The findings of magnetic measurements indicate that manufacturing-induced stresses significantly increase magnetization demand and core losses-up to 650% and 53%, respectively. These effects lead to a 4.2% reduction in maximum air gap torque and notable changes in torque characteristic curves and d-axis flux linkage maps. Including realistic magnetic data yielded torque predictions closely aligned with experimental results and reduced discrepancy in core loss simulation by more than 50%. The study’s findings indicate that accounting for manufacturing influences in material characterization enhances modeling accuracy and enables optimized electrical machine designs and control strategies.