TY - CHAP A1 - Küchler, Andreas A1 - Schober, F. A1 - Harrer, S. A1 - Krause, Ch. A1 - Berger, Frank T1 - Einfluss von Temperatur und Ligningehalt auf die elektrische Leitfähigkeit von Pressspan als HGÜ-Isolierwerkstoff T2 - 6. RCC-Fachtagung „Werkstoffe zur Anwendung in der el. Energietechnik unter den besonderen Anforderungen der HGÜ“ Y1 - 2015 SP - 268 EP - 273 CY - Berlin ER - TY - CHAP A1 - Küchler, Andreas A1 - Schober, F. A1 - Harrer, S. A1 - Wolfinger, T. A1 - Krause, Ch. A1 - Exner, W. A1 - Berger, Frank T1 - Leitfähigkeit von Pressspan als diagnostische Kenngröße für HGÜ-Betriebsmittel BT - ETG-Fachtagung Diagnostik Elektrischer Betriebsmittel T2 - ETG-Fachbericht 144 Y1 - 2014 PB - VDE CY - Berlin ER - TY - BOOK A1 - Eckert, Ludwig T1 - Ein Beitrag zur Implementierung autonomer, intelligenter und feldbusgestützter Sensor-/Aktorsysteme im Feldbereich (CASE/SA) Y1 - 1999 SN - 3183571102 PB - VDI ER - TY - CHAP A1 - Küchler, Andreas T1 - Ausbildung und Steuerung elektrischer Felder bei Gleichspannungsbeanspruchung T2 - 6. RCC-Fachtagung „Werkstoffe zur Anwendung in der el. Energietechnik unter den besonderen Anforderungen der HGÜ“ Y1 - 2015 SP - 12 EP - 50 CY - Berlin ER - TY - CHAP A1 - Küchler, Andreas A1 - Reumann, Andreas A1 - Wirth, Isabell A1 - Langens, Achim A1 - Berger, Frank T1 - Erfassung transienter elektrischer Potentialverteilungen in thermisch hoch belasteten Gleichspannungsdurchführungen BT - ETG-Fachtagung Diagnostik Elektrischer Betriebsmittel T2 - ETG-Fachbericht 144 N2 - Mit Hilfe kapazitiver Steuerung können Durchführungen hochspannungsführende Leiter durch geerdete Wände in Gebäuden oder Geräten führen. Bei zeitveränderlichen Belastungen (Stoß-, Wechselspannungen) wird die gewünschte Potentialaufteilung durch die Kapazitäten zwischen den leitfähigen Steuerbelägen erzwungen. Bei Gleichspannung ergibt sich eine resistive Steuerung, die bei homogener Leitfähigkeit des Isolierkörpers eine prinzipiell gleichartige Potentialaufteilung ergibt. Durchführungen sind jedoch thermisch hoch belastete Betriebsmittel, in denen starke Temperaturgradienten und in ihrer Folge starke Leitfähigkeitsgradienten entstehen, die zu einer erheblichen Verschiebung der Potentialverteilung führen können [1]. Für Design und Diagnose ist das Verständnis dieser bisher nur theoretisch erfassbaren Vorgänge von großer Bedeutung. Deshalb wurden für experimentelle Untersuchungen zwei identische Durchführungskörper hergestellt, die mit Temperaturfühlern für thermische Messungen bzw. mit Anzapfungen für die Erfassung von elektrischen Potentialen ausgerüstet wurden. Die identische Beheizung beider Leiterrohre erlaubt es, eine Korrelation gemessener thermischer und elektrischer Profile und Transienten herzustellen. Für rückwirkungsfreie Messung der Gleichspannungspotentiale wurde ein Rotationsvoltmeter benutzt. Die Untersuchungen bestätigen das theoretisch erwartete thermisch-elektrische Verhalten und sie zeigen, dass erhebliche transiente und stationäre elektrische Belastungen auftreten können, die im Zusammenhang mit thermischen Transienten und Belastungen gesehen werden müssen. Sie sind beim Design in Rechnung zu stellen und sie zeigen, dass die bei dielektrischen Diagnosemessungen erfassten Materialkenngrößen wichtige Aussagen über den elektrischen Belastungszustand der Durchführung liefern können. Y1 - 2014 UR - https://www.vde-verlag.de/proceedings-de/453648016.html PB - VDE CY - Berlin ER - TY - CHAP A1 - Küchler, Andreas A1 - Hüllmandel, F. A1 - Appold, M. A1 - Liebschner, M. A1 - Krump, R. A1 - Titze, J. T1 - Diagnose von Hochspannungsdurchführungen durch PDC-Analyse BT - ETG-Fachtagung „Diagnostik elektrischer Betriebsmittel“ T2 - ETG-Fachbericht 104 Y1 - 2006 PB - VDE CY - Kassel ER - TY - CHAP A1 - Küchler, Andreas A1 - Hüllmandel, F. A1 - Böhm, K. A1 - Koch, N. T1 - Einfluss äußerer Grenzflächen auf die dielektrische Diagnose betriebsgealterter Hochspannungsdurchführungen BT - ETG-Fachtagung „Grenzflächen in elektrischen Isoliersystemen“ T2 - ETG-Fachbericht 99 Y1 - 2009 PB - VDE CY - Hanau ER - TY - CHAP A1 - Küchler, Andreas A1 - Zink, M. A1 - Berger, Frank T1 - Kompensation des Temperatureinflusses auf dielektrische Messungen im Zeitbereich zur Beschreibung von Isolierwerkstoffen BT - ETG-Fachtragung „Grenzflächen in elektrischen Isoliersystemen“ T2 - ETG-Fachbericht 140 Y1 - 2013 PB - VDE CY - Dresden ER - TY - CHAP A1 - Küchler, Andreas A1 - Hüllmandel, F. A1 - Böhm, K. A1 - Liebschner, M. A1 - Appold, M. A1 - Krump, R. A1 - Titze, J. T1 - Dielectric Diagnosis and Monitoring of High Voltage Bushings BT - Kolloquium T2 - 51. IWK Int. Wissenschaft Y1 - 2006 PB - Technische Universität Ilmenau CY - Ilmenau ER - TY - CHAP A1 - Küchler, Andreas A1 - Elliott, F.E. A1 - Lavier, B. A1 - Kühn, W. T1 - FEM-Study on converter transformer failures in the Celilo HVDC converter station T2 - IEEE PES winter power meeting Y1 - 1999 CY - USA ER - TY - CHAP A1 - Küchler, Andreas A1 - Krump, R. A1 - Haberecht, P. A1 - Titze, J. A1 - Liebschner, M. T1 - Bushings for Highest Voltages BT - Development, Testing, Diagnostics and Monitoring T2 - Highvolt-Kolloquium Y1 - 2007 CY - Dresden ER - TY - CHAP A1 - Küchler, Andreas A1 - Dunz, Th. A1 - Hinderer, A. A1 - Schwab, A. T1 - Transient Field Distribution Measurments with Electrically Long Sensors T2 - 5th ISH Int. Symp. on High Voltage Engineering Y1 - 1987 SP - 08 EP - 32 CY - Braunschweig ER - TY - JOUR A1 - Kaupp, Tobias T1 - Lehre, Forschung und Transfer am Beispiel der Robotik BT - vom RoboCup@Work zur autonomen Warenkommissionierung JF - FHWS Science Journal N2 - Das IDEE ist mit vier Forschungsprofessoren besetzt, die durch eine Lehrentlastung Freiräume für den Auf- und Ausbau von interdisziplinären Forschungsaktivitäten nutzen können. Das Center Robotik (CERI) ist eines der Aufgabengebiete des IDEEs mit den beiden Schwerpunkten »Robotergestützte Arbeitsplätze der Zukunft« sowie »Intralogistik in der Smart Factory«. Dieser Artikel beschäftigt sich mit dem zweiten Schwerpunkt. Anhand der CERI Aktivitäten im Bereich der fahrerlosen Transportsysteme wird aufgezeigt, wie der »Dreiklang« Forschung, Lehre und Transfer in der Praxis umgesetzt wird und die drei Bestandteile sich gegenseitig befruchten können. KW - robotik Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:863-opus-20065 UR - https://nbn-resolving.org/urn:nbn:de:bvb:863-opus-19389 SN - 2196-6095 VL - 5 IS - 2 SP - 109 EP - 116 ER - TY - THES A1 - Wirth, Isabell T1 - Berücksichtigung dielektrischer Materialeigenschaften in der Finiten-Elemente-Simulation von HGÜ-Isoliersystemen T2 - Ilmenauer Beiträge zur elektrischen Energiesystem‐, Geräte- und Anlagentechnik N2 - Verbrauchsfern erzeugter Strom aus regenerativen Energien kann über große Distanzen am wirtschaftlichsten mittels der Hochspannungsgleichstromübertragung (HGÜ) transportiert werden. Die HGÜ führt zu einer veränderten elektrischen Belastung der Hochspannungskomponenten. Transiente Übergangsvorgänge bestimmen die elektrischen Feldverteilungen. Bei der Berechnung elektrischer Feldverteilungen in Isoliersystemen für die Hochspannungsgleichstromübertragung (HGÜ) mit Hilfe der Finiten-Elemente-Methode (FEM) wurden die dielektrischen Eigenschaften bisher in Form von Permittivitäten und parameterabhängigen Leitfähigkeiten berücksichtigt. Langsame Polarisationsvorgänge werden dabei nicht berücksichtigt. Für die Berechnung komplexer Isoliersysteme durch die FEM ist deshalb die Beschreibung der langsamen Polarisationsvorgänge im Isolierstoff durch Differentialgleichungen wünschenswert, die direkt in die FEM einbezogen werden und mit denen je nach Bedarf sowohl einzelne Polarisationsmechanismen als auch ihre Überlagerungen berücksichtigt werden können. In dieser Arbeit werden hierfür auf Basis des bekannten Debye-Ansatzes, und in Analogie zum Netzwerkmodell, zusätzlich zu den Gleichungen, die Verschiebungs- und Leitungsströme beschreiben, weitere Differentialgleichungen direkt in die FEM einbezogen, welche die feld- und temperaturabhängigen Polarisationsströme individuell abbilden. Die Materialfunktionen und ihre Parameter werden durch Messung von Polarisations- und Depolarisationsströmen (PDC) ermittelt. Durch die Implementierung von beliebigen Polarisationsmechanismen in einem FEM-Programm wurde eine Lücke der Berechnungsmöglichkeiten von komplexen, auch dreidimensionalen Isoliersystemen geschlossen, in denen oftmals stationäre oder transiente Temperaturgradienten vorliegen und in denen sich transiente elektrische Feldverteilungen ausbilden. Zur Verifizierung des beschriebenen Berechnungsverfahrens werden transiente Potentialverläufe an den Steuerbelägen von entsprechend modifizierten Hochspannungsdurchführungen unter Gleich- und Umpolspannungen sowie unter thermischen Gradienten gemessen. Dabei kann eine bisher nicht erreichte Übereinstimmung der transienten und stationären Potentialverläufe zwischen FEM-Simulation und Messung erzielt werden. Auswirkungen auf Prüf- und Belastungsszenarien werden anhand von Simulationen diskutiert. N2 - Consumer-remotely generated electricity from renewable energies can be transported over long distances most economically by means of high-voltage direct current (HVDC) transmission. The HVDC leads to a change in the electrical stress on the high-voltage components. Transient processes determine the electric field distributions. Calculations of electrical field distributions in insulation systems for high-voltage direct current (HVDC) transmission using the finite element method (FEM) by default consider the dielectric properties in the form of permittivities and parameter-dependent conductivities. Thereby, slow polarisation processes are not considered. For FEM calculation of complex insulation systems, a description of slow polarisation processes in insulating materials is therefore desirable. Differential equations should be directly implemented into the FEM in order to consider individual polarisation processes as well as their superposition, according to demand. In this work, differential equations based on the well-known Debye approach, and in analogy with the equivalent-circuit model, are directly implemented into the FEM. Thereby, field-dependent and temperature-dependent polarisation currents are represented individually and additionally to the equations describing displacement currents and conduction currents. Material functions and their parameters are determined by measuring the polarisation and depolarisation currents (PDC). The implementation of any desired polarisation mechanisms in a FEM program has closed a gap in the computational possibilities of complex and even three-dimensional insulation systems, which often have stationary or transient temperature gradients and which show transient electrical field distributions. For the verification of the described calculation method, measurements of transient voltage profiles were made at the grading layers of modified high voltage bushings being stressed with DC voltage, polarity reversals and being subject to thermal gradients. It is shown that a previously unattainable agreement of the transient and stationary potential profiles between FEM simulation and measurement can be achieved. Effects on test and load scenarios are discussed based on simulation results. KW - Hochspannungsgleichstromübertragung KW - Isolierstoff KW - Dielektrische Eigenschaft KW - Finite-Elemente-Methode Y1 - 2020 UR - https://nbn-resolving.org/urn:nbn:de:gbv:ilm1-2019000601 SN - 978-3-86360-215-4 U6 - https://doi.org/10.22032/dbt.41185 IS - 26 PB - Universitätsverlag Ilmenau CY - Ilmenau ER - TY - THES A1 - Zimmermann, Korbinian T1 - Verwaltung von Trainingsdaten für Künstliche Intelligenz N2 - In order to operate a permanent magnet synchronous motor (PSM) as efficiently as possible, it requires precise information about the current thermal state of the electric drive. In most production vehicles, rotor and stator thermocouples are not used for financial reasons. Within the development of a temperature model based on the physical approach, measurements are carried out with a telemetry unit installed in the electric motor. These take place both on the test bench and in the test vehicle. The resulting measurement records give reason to investigate a data-based approach using deep learning, which is the aim of this work. In addition to the evaluation of the existing test bench and vehicle data, the focus is on the development of a neural temperature model. The results obtained will be compared with the existing ECU temperature model. Y1 - 2022 EP - 92 ER - TY - JOUR A1 - Mathes, Markus A1 - Seufert, Jochen T1 - Programmieren in C++ für Elektrotechniker und Mechatroniker BT - Das Lern- und Übungsbuch N2 - Das Buch Programmieren in C++ für Elektrotechniker und Mechatroniker bietet einen Einstieg in die moderne Softwareentwicklung für Studierende der Ingenieurwissenschaften. Dabei wird ein durchgängiger Ansatz verfolgt, der, beginnend mit den Grundlagen der Programmierung, bis hin zu weiterführenden Themen, wie Hardware-nahe Programmierung, zahlreiche Themengebiete betrachtet und Studierende nicht nur für die Prüfung, sondern auch für den Arbeitsalltag vorbereitet. Da man Programmieren nur durch Üben erlernen kann, liefert das Buch einen umfangreichen Aufgabenkatalog. Y1 - 2022 SN - 978-3-658-38501-9 U6 - https://doi.org/10.1007/978-3-658-38501-9 PB - Springer Vieweg CY - Wiesbaden ER - TY - JOUR A1 - Gustavsen, B. A1 - Rahimpour, Ebrahim T1 - High-Frequency Transformer and Reactor Models for Network Studies, Part E: Measurements and transformer design details JF - Conseil International des Grands Réseaux Électriques (CIGRE) TB 904 Y1 - 2023 SN - 978-2-8587-3609-6 SP - 1 EP - 140 ER - TY - JOUR A1 - Gustavsen, B. A1 - Rahimpour, Ebrahim T1 - High-Frequency Transformer and Reactor Models for Network Studies, Part D: Model interfacing and specifications JF - Conseil International des Grands Réseaux Électriques (CIGRE) TB 903 Y1 - 2023 SN - 978-2-8587-3608-9 SP - 1 EP - 43 ER - TY - JOUR A1 - Gustavsen, B. A1 - Rahimpour, Ebrahim T1 - High-Frequency Transformer and Reactor Models for Network Studies, Part B: Black-Box Models JF - Conseil International des Grands Réseaux Électriques (CIGRE) TB 901 Y1 - 2023 SN - 978-2-8587-3606-5 SP - 1 EP - 88 ER - TY - JOUR A1 - Gustavsen, B. A1 - Rahimpour, Ebrahim T1 - High-Frequency Transformer and Reactor Models for Network Studies, Part A: White-Box Models JF - Conseil International des Grands Réseaux Électriques (CIGRE) TB 900 Y1 - 2023 SN - 978-2-8587-3605-8 SP - 1 EP - 203 ER - TY - BOOK A1 - Küchler, Andreas T1 - Erfassung transienter elektromagnetischer Feldverteilungen mit konzentrierten und räumlich ausgedehnten Sensoren T3 - Fortschritt-Berichte VDI, Reihe 21 - 7 Y1 - 1986 PB - VDI CY - Düsseldorf ER - TY - CHAP A1 - Küchler, Andreas A1 - Hammer, F. A1 - Mäueler, G. T1 - Behaviour of Bushings with Silicone Rubber Sheds T2 - 6th ISH Int. Symp. on High Voltage Engineering Y1 - 1989 SP - 38 EP - 47 CY - New Orleans, LA, USA ER - TY - JOUR A1 - Holder, Marvin Alexander Samuel A1 - Eberspächer, Mark T1 - Systematic methods for the synthesis of equidistant MIMO arrays JF - Advances in Radio Science N2 - Finding a feasible antenna arrangement for multiple input multiple output (MIMO) arrays to serve a specific purpose is a first crucial step towards a successful MIMO radar system design. Design methods to synthesize uniformly weighted and equidistant MIMO arrays are proposed and investigated. The methods can be used to gain a design foundation for 1D or 2D arrays without software tools or programming effort. Since the presented approach does not consider electromagnetic fields, electromagnetic full-wave simulations might be required additionally. The method is based on sequentially copying and displacing antenna groups with the help of a number scheme. A nomenclature is proposed to classify the degrees of freedom in the design procedure. If the antennas are aligned to a uniform grid, a polynomial representation of the array can be chosen alternatively. This method is beneficial when redundancies of a produced array and where they appear must be analyzed. A new design problem arises when an array is to consist of only transceiving antennas, which can be analyzed with polynomial multiplication. One strategy to find a suitable MIMO array consisting of transceiver elements is given and evaluated. Y1 - 2023 UR - https://ars.copernicus.org/articles/21/15/2023/ U6 - https://doi.org/10.5194/ars-21-15-2023 VL - 21 SP - 15 EP - 23 ER - TY - JOUR A1 - Roser, Philipp A1 - Birkhold, Annette A1 - Preuhs, Alexander A1 - Stimpel, Bernhard A1 - Syben, Christopher A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - Fully-automatic CT data preparation for interventional X-ray skin dose simulation JF - Bildverarbeitung für die Medizin 2020: Algorithmen - Systeme - Anwendungen. Proceedings des Workshops vom 15. bis 17. März 2020 in Berlin Y1 - 2020 U6 - https://doi.org/10.1007/978-3-658-29267-6_26 SP - 125 EP - 130 PB - Springer Fachmedien CY - Wiesbaden ER - TY - JOUR A1 - Busch, Erik A1 - Strobel, Norbert A1 - Nobach, Kai A1 - Bulitta, Clemens A1 - Hirshfeld, John W. A1 - Lin, Wu A1 - de Abreu, Marcel Gama T1 - Optimizing the innovation and development process of medical devices - a study based on angiographic equipment JF - Health and Technology Y1 - 2021 UR - https://link.springer.com/article/10.1007/s12553-021-00537-7 U6 - https://doi.org/doi.org/10.1007/s12553-021-00537-7 VL - 11 IS - 3 SP - 563 EP - 574 ER - TY - JOUR A1 - Roser, Philipp A1 - Birkhold, Annette A1 - Preuhs, Alexander A1 - Ochs, Philipp A1 - Stepina, Elizaveta A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - XDose: toward online cross-validation of experimental and computational X-ray dose estimation JF - International Journal of Computer Assisted Radiology and Surgery Y1 - 2020 U6 - https://doi.org/10.1007/s11548-020-02298-6 VL - 16 IS - 2 ER - TY - JOUR A1 - Roser, Philipp A1 - Birkhold, Annette A1 - Preuhs, Alexander A1 - Syben, Christopher A1 - Felsner, Lina A1 - Hoppe, Elisabeth A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - X-ray Scatter Estimation Using Deep Splines JF - IEEE Transactions on Medical Imaging Y1 - 2021 UR - https://arxiv.org/pdf/2101.09177.pdf VL - 40 IS - 9 SP - 2272 EP - 2283 ER - TY - JOUR A1 - Hariharan, Sai Gokul A1 - Strobel, Norbert A1 - Kaethner, Christian A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Navab, Nassir T1 - Data-driven estimation of noise variance stabilization parameters for low-dose x-ray images JF - Physics in Medicine and Biology Y1 - 2020 U6 - https://doi.org/10.1088/1361-6560/abbc82 VL - 65 IS - 22 ER - TY - JOUR A1 - Zhong, Xia A1 - Strobel, Norbert A1 - Birkhold, Annette A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - A machine learning pipeline for internal anatomical landmark embedding based on a patient surface model JF - International Journal of Computer Assisted Radiology and Surgery Y1 - 2019 U6 - https://doi.org/10.1007/s11548-018-1871-y VL - 14 IS - 1 SP - 53 EP - 61 ER - TY - JOUR A1 - Shetty, Karthik A1 - Birkhold, Annette A1 - Jaganathan, Srikrishna A1 - Strobel, Norbert A1 - Egger, Bernhard A1 - Kowarschik, Markus A1 - Maier, Andreas T1 - BOSS: Bones, organs and skin shape model JF - Computers in Biology and Medicine Y1 - 2023 UR - https://arxiv.org/pdf/2303.04923.pdf SN - 0010-4825 VL - 165 ER - TY - JOUR A1 - Gustavsen, B. A1 - Rahimpour, Ebrahim T1 - High-Frequency Transformer and Reactor Models for Network Studies, Part C: Grey Box Models JF - Conseil International des Grands Réseaux Électriques (CIGRE) TB 902 Y1 - 2023 SN - 978-2-8587-3607-2 SP - 1 EP - 102 ER - TY - JOUR A1 - Adamy, Jürgen A1 - Voutsas, Kyriakos A1 - Willert, Volker T1 - Ein binaurales Richtungshörsystem für mobile Roboter in echoarmer Umgebung JF - at - Automatisierungstechnik N2 - In diesem Beitrag wird ein binaurales Lokalisationsmodell für einen autonomen mobilen Roboter vorgestellt, das sich am menschlichen Hörsystem orientiert. Im Mittelpunkt steht die technische Umsetzung der neuronalen Verarbeitungsmechanismen der Olivenkerne des auditorischen Systems, die ein binaurales Richtungshören ermöglichen. Das System ist in der Lage, im Bereich des Sichtfeldes des Roboters eine Schallquelle in echoarmer, d.h. reflexionsarmer Umgebung anhand von Laufzeitunterschieden und Pegeldifferenzen zu lokalisieren. Die Möglichkeit des Richtungshörens verbessert die Wahrnehmung der unmittelbaren Umgebung des Roboters entscheidend und erlaubt z.B. die Ausrichtung des Roboterkopfes zur Schallquelle. Y1 - 2003 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:863-opus-60022 SN - 2196-677X VL - 51 IS - 9 SP - 387 EP - 395 PB - Walter de Gruyter GmbH ER - TY - CHAP A1 - Holder, Marvin A1 - Eberspächer, Mark A1 - Waldschmidt, Christian T1 - Radar imaging device using prism shaped aperture T2 - 2024 Kleinheubach Conference Y1 - 2024 U6 - https://doi.org/10.23919/IEEECONF64570.2024.10738992 SP - 1 EP - 4 PB - IEEE ER - TY - THES A1 - Ziegler, Andreas ED - Montesinos-Miracle, Daniel ED - Ackva, Ansgar T1 - Possibilities and limitations of active battery management systems for lithium-ion batteries N2 - Lithium-Ion Batteries (LIBs) are being used in more and more areas of application. At the same time, their chemical composition and their designs are constantly evolving. Major developments are also taking place in the field of Battery Management Systems (BMSs), which are essential for the safe operation of LIBs. The focus is on intelligent charge redistribution between individual cells, called Active Balancing (AB). This thesis deals with the possibilities and limitations of AB. An empirical long-term experiment provides new insights into the ageing behaviour of batteries that are actively balanced during their entire service life. The main objective of this work is to to demonstrate influences on the ageing behaviour of batteries that are still unknown at present. A literature study shows that previous work in this area is often based on theoretical approaches and rarely has a functional proof through measurement results. Most significant statements from literature are examined. These include the increase in discharge capacity, energy efficiency and service life associated with AB, as well as lower parameter variation of the individual cells installed in the battery. Before starting the empirical experiment, the current state of the art is captured and a universal AB topology is selected from a large number of known systems. The operating behaviour as well as the balancing algorithms are explained in detail in order to be able to understand the influences occurring during the ageing of the batteries. The ageing experiment itself is a comparison test between commercial Passive Balancing (PB) and the novel AB. Two identical battery packs are aged under uniform conditions, but with the two different BMSs mentioned above. At the end of the ageing process, the battery packs are disassembled and the parameters of all individual cells are determined for further investigation. The main contribution of this work is the proof of effects through AB, especially with large battery loads. Both the increase in discharge capacity and the service life are demonstrated. The work shows how parameter variation of individual cells can be made visible during operation. It also presents diagnosis and calculation methods. The energetic efficiency of the batteries cannot be increased, since the self-consumption of the power electronics of the AB system is always higher than with PB. However, the overall efficiency of the battery increases due to an increase in capacity and an extension of the service life. The thesis also shows that with lower battery loads, the use of AB is not beneficial any more or may lead to negative effects. In such applications conventional PB is sufficient. The results obtained during pack ageing are additionally substantiated and extended by the measurement results of the individual cells. At the end of the thesis, all results and contributions are summarised. Suggestions for optimisation as well as further research ideas are presented as a possible starting point for further scientific studies. Y1 - 2023 UR - http://hdl.handle.net/10803/687388 ER - TY - JOUR A1 - Gensler, Marius A1 - Malkmus, Christoph A1 - Ockermann, Philipp A1 - Möllmann, Marc A1 - Hahn, Lukas A1 - Salehi, Sahar A1 - Luxenhofer, Robert A1 - Boccaccini, Aldo R. A1 - Hansmann, Jan T1 - Perfusable Tissue Bioprinted into a 3D-Printed Tailored Bioreactor System JF - Bioengineering N2 - Bioprinting provides a powerful tool for regenerative medicine, as it allows tissue construction with a patient’s specific geometry. However, tissue culture and maturation, commonly supported by dynamic bioreactors, are needed. We designed a workflow that creates an implant-specific bioreactor system, which is easily producible and customizable and supports cell cultivation and tissue maturation. First, a bioreactor was designed and different tissue geometries were simulated regarding shear stress and nutrient distribution to match cell culture requirements. These tissues were then directly bioprinted into the 3D-printed bioreactor. To prove the ability of cell maintenance, C2C12 cells in two bioinks were printed into the system and successfully cultured for two weeks. Next, human mesenchymal stem cells (hMSCs) were successfully differentiated toward an adipocyte lineage. As the last step of the presented strategy, we developed a prototype of an automated mobile docking station for the bioreactor. Overall, we present an open-source bioreactor system that is adaptable to a wound-specific geometry and allows cell culture and differentiation. This interdisciplinary roadmap is intended to close the gap between the lab and clinic and to integrate novel 3D-printing technologies for regenerative medicine. Y1 - 2024 U6 - https://doi.org/10.3390/bioengineering11010068 SN - 2306-5354 VL - 11 IS - 1 PB - MDPI ER - TY - JOUR A1 - Hein, Thiemo A1 - Oeser, David A1 - Ziegler, Andreas A1 - Montesinos-Miracle, Daniel A1 - Ackva, Ansgar T1 - Aging Determination of Series-Connected Lithium-Ion Cells Independent of Module Design JF - Batteries N2 - In this work, a battery consisting of eight commercial NMC/graphite cells connected in series was cycled to 60% of its initial capacity. During the test, special care was taken to ensure that the results were not influenced by either the module assembly or the module design. For this purpose, the cells were virtually connected in a laboratory environment with the help of the test device as if they were operated together in a battery. Extrinsic influences that affect cell aging were thus reduced to a minimum. Differential Voltage Analysis (DVA), Electrochemical Impedance Spectrum (EIS), and relaxation measurements were performed to analyze the aging behavior of each cell. The results show that despite a theoretically perfect module design, Cell-to-Cell Variations (CtCV) occurred during aging. The shifting Depth of Discharge (DoD) values among the cells further amplify CtCV. Lithium plating was also observed in the faster aging cells after cyclic aging, suggesting that this aging effect contributes significantly to the development of CtCV. After the aging test, the battery was equipped with an active balancing system that maximizes capacity utilization. More important, the balancing charges which are calculated iteratively within the used balancing algorithm show a strong correlation to the pure capacity losses and thus provide a new way to determine the capacity values of each cell individually without disassembling the battery. Y1 - 2023 U6 - https://doi.org/10.3390/batteries9030172 VL - 9 IS - 3 ER - TY - RPRT A1 - Ackva, Ansgar T1 - Hochdynamischer Umrichter in Hybridstruktur : Schlussbericht im Förderprogramm FHprofUnt : Laufzeit des Vorhabens: 01.10.2012 bis 30.09.3015 Y1 - 2016 U6 - https://doi.org/10.2314/gbv:876282885 PB - Hochschule für angewandte Wissenschaften Würzburg-Schweinfurt CY - Schweinfurt ER - TY - RPRT A1 - Ackva, Ansgar A1 - Küchler, Andreas T1 - Konvergenz elektrischer Energietechnologien : Akronym: KEE-TECH : Schlussbericht zur Erstellung des Strategiekonzepts Y1 - 2016 U6 - https://doi.org/10.2314/GBV:883086484 PB - Hochschule für angewandte Wissenschaften Würzburg-Schweinfurt CY - Würzburg ER - TY - RPRT A1 - Ackva, Ansgar T1 - Vorhabenbezeichnung: Bat-PA-40 : Schlussbericht : Berichtszeitraum: 01.02.2018 bis 31.01.2019 Y1 - 2019 U6 - https://doi.org/10.2314/kxp:1681868938 PB - Hochschule für Angewandte Wissenschaften Würzburg-Schweinfurt ER - TY - RPRT A1 - Ackva, Ansgar T1 - Multilevel-Umrichter Prüfsystem : Schlussbericht : Berichtszeitraum: 01.09.2014-31.08.2015 Y1 - 2016 U6 - https://doi.org/10.2314/gbv:872408639 PB - Hochschule für angewandte Wissenschaften Würzburg-Schweinfurt CY - Schweinfurt ER - TY - JOUR A1 - Holder, Marvin A1 - Eberspächer, Mark A1 - Waldschmidt, Christian T1 - A hybrid algorithm to process millimeter wave images with prism-shaped aperture JF - Advances in Radio Science N2 - To process images of a prism-shaped aperture in a radar imaging context, a hybrid algorithm is derived. This hybrid algorithm combines the benefits of backprojection and the Omega-K algorithm in terms of computational performance and flexibility. As a demonstration for an application of this algorithm, a 3D inspection system based on millimeter wave imaging is introduced. The system scans through the object, while it is passing on a conveyor belt. It comprises a curved antenna layout, which is able to synthesize the prism-shaped aperture. This aperture is shown to have superior resolution capabilities compared to a planar aperture. Some potential pitfalls when implementing the hybrid algorithm are assessed. Approximation formulae to estimate the achievable resolution are derived. The introduced algorithm is analyzed regarding its point spread function and compared to backprojection with the help of numerical simulations to demonstrate its potential. Y1 - 2025 U6 - https://doi.org/10.5194/ars-23-101-2025 SN - 1684-9973 VL - 25 IS - 23 SP - 101 EP - 111 PB - Copernicus GmbH ER - TY - JOUR A1 - Yükselen, Emir A1 - Rahimpour, Ebrahim T1 - An improvement in the design process of sustainable peak power rating transformer for solar utility JF - International Journal of Electrical Power & Energy Systems N2 - The transformer industry faces critical challenges, such as maintaining reliable production while meeting rising sustainability requirements. This paper introduces a significant advancement in the design and optimization of a transformer dedicated to a photovoltaic power plant, which exhibits a unique loading cycle distinct from standard power and distribution transformers. The main aim is to minimize the carbon footprint by enhancing the design process to improve operational performance, efficiency, and functional reliability. Such upgrades are essential for transitioning to a zero-emission electricity system and developing green energy projects. In this paper, a transformer has been studied using a combination of electrical design and 3D finite element method simulation to evaluate various design parameters. An optimization study has been conducted using an innovative multi-objective genetic algorithm utilizing a cost function that factors in size and material costs to identify the most efficient and cost-effective design solutions. The proposed design method was then validated through thermal model simulations and experimental tests based on the photovoltaic load cycle. A comparison of critical thermal parameters directly affecting the transformer’s lifetime and reliability was also drawn. The results were consistent with the expected outcomes, confirming the effectiveness and reliability of the proposed design methodology. KW - Transformer KW - Photovoltaic KW - Finite element method KW - Optimization KW - Genetic algorithm Y1 - 2025 U6 - https://doi.org/https://doi.org/10.1016/j.ijepes.2025.110928 SN - 0142-0615 VL - 170 SP - 1 EP - 13 PB - Elsevier BV ER - TY - CHAP A1 - Yükselen, Emir A1 - Rahimpour, Ebrahim T1 - An Optimization Approach for Sustainable Transformer Design in Photovoltaic Power Plants”, 4th IEEE International Conference on Power Electronics Smart Grid and Renewable Energy T2 - 4th IEEE International Conference on Power Electronics Smart Grid and Renewable Energy Y1 - 2025 ER - TY - CHAP A1 - Meuser, Martin A1 - Rahimpour, Ebrahim T1 - Analyzing of Non-Standard Overvoltages in Different Types of Power Transformer Windings Using Frequency Domain and Time Domain Severity Factors T2 - CIGRE SC A2 & D1 Joint Colloquium Y1 - 2025 ER - TY - CHAP A1 - Rahimpour, Ebrahim A1 - Portillo, A. A1 - Dragostinov, S. T1 - Testing Challenges in Impulse Testing of Transformers T2 - CIGRE SC A2 & D1 Joint Colloquium Y1 - 2025 ER - TY - CHAP A1 - Abouhosseini-Darzi, Mohammad A1 - Rahimpour, Ebrahim A1 - Mirzaie, Mohammad A1 - Shayegani Akmal, Amir Abbas T1 - Investigating the Effects of Moisture Distribution on the Electric Field and Leakage Current of Power Transformer Bushings T2 - IEEE Electrical Insulation Conference (EIC) N2 - Bushings are one of the most important and essential equipment of power transformers. Statistics show that one of the main causes of transformer failures is due to bushing problems. One of the main reasons for bushing failures is the penetration of moisture into its internal insulation system. The moisture affects the dielectric properties and leads to an increase in its leakage current. These effects lead to changes in the electric field of the inner insulating layers of the bushings, so it is necessary to investigate these effects. In this paper, the changes of the electric field in the insulating layers of a sample bushing have been investigated with considering the different moisture distribution between the layers. This evaluation has been done during the moisture diffusion time, from the start of penetration to the time of uniformity of moisture in all layers. Also, the moisture effects on the bushing leakage current under above conditions have been studied. For this purpose, an OIP bushing is modeled in COMSOL Multiphysics software and the simulations are carried out based on Finite Element Method (FEM) and finally the obtained results are analyzed. The results show that the moisture distribution in the bushing can have an important effect on the internal electric fields. Also, according to the results, the moisture distribution inside the bushing does not have a great effect on the leakage current and this current is only affected by the volume of the moisture penetrated inside the bushing. KW - Multiphysics KW - Analytical models KW - Moisture KW - Insulators KW - Software KW - Finite element analysis KW - Leakage currents KW - Reliability KW - Electric fields KW - Power transformer insulation KW - Transformer Bushing KW - Moisture Content KW - Electric Field Distribution KW - Leakage Current KW - Finite Element Method (FEM) KW - Transformative Power KW - Moisture Distribution KW - Finite Element Method KW - Effect Of Moisture KW - COMSOL Multiphysics Software KW - Internal Electric Field KW - Insulation System KW - Moisture Diffusion KW - Conductive KW - Dielectric Constant KW - Relaxation Time KW - Distribution Of Effects KW - Aluminum Foil KW - Radial Direction KW - Axial Direction KW - Electric Distribution KW - Concentric Layers KW - Maximum Field KW - Maximum Electric Field KW - Resistance Components KW - Average Moisture Content KW - Capacitive Component KW - Relative Electrical Conductivity KW - Complex Relative Permittivity KW - Amount Of Moisture Y1 - 2025 SN - 979-8-3315-2608-5 U6 - https://doi.org/10.1109/EIC63069.2025.11123376 SN - 2993-3684 PB - IEEE ER - TY - JOUR A1 - Abouhosseini-Darzi, Mohammad A1 - Mirzaie, Mohammad A1 - Shayegani Akmal, Amir Abbas A1 - Rahimpour, Ebrahim T1 - Calculation and Analysis of the Electric Field of the OIP Bushings under Internal Humidity and Surface Polluted Conditions using FEM JF - Iranian Journal of Electrical and Electronic Engineering N2 - Bushings are one of the most important components of electrical equipment such as power transformers, reactors, capacitors. Most of the installed bushings have Oil-Immersed Paper (OIP) insulation structure. Bushing failure is caused by various reasons such as poor manufacturing process, overloading and also poor installation process, but moisture ingress is one of the main reasons of OIP bushing defect during its operation. In this paper, the electric field distribution of OIP bushings in multiple situations are simulated and effects of moisture distribution are analyzed. The simulations are stablished in polluted and clean surfaces of the studied bushing and done by COMSOL Multiphysics Software. The results show that non-uniform moisture distribution has a significant effect on electric fields of OIP insulation. This effect strongly increases with increasing the pollution on the external insulator of the bushing. © 2025, Iran University of Science and Technology. All rights reserved. KW - Finite Element Method (FEM) KW - Moisture KW - OIP Bushing KW - Pollution KW - Transformer Y1 - 2025 U6 - https://doi.org/10.22068/IJEEE.21.3.3360 VL - 21 IS - 3 SP - 1 EP - 11 ER - TY - CHAP A1 - Al-Abadi, A. A1 - Rahimpour, Ebrahim A1 - Gamil, Ahmed T1 - Dynamisches thermisches Verhalten von mit Ester-Flüssigkeit gefüllten Transformatoren für Offshore-Windkraftanwendungen in kalten Klimazonen T2 - 18th Transformer-Life-Management Konferenz Y1 - 2025 ER - TY - CHAP A1 - Rahimpour, Ebrahim A1 - Ghorbal, Mohammed Bilal A1 - Mirzaei, Hassan Reza T1 - Application of the Nonlinear Kernel Principal Component Analysis in Detecting Disk-to-Disk Faults along a Transformer Winding T2 - 3rd International Conference – Tesla Innovation Days Y1 - 2025 ER - TY - CHAP A1 - Ghorbal, Mohammed Bilal A1 - Mirzaei, Hassan Reza A1 - Rahimpour, Ebrahim T1 - Detection of Disk Space Variation in Power Transformers using Nonlinear Dimensionality Reduction Algorithm T2 - 24th International Symposium on High Voltage Engineering Y1 - 2025 ER - TY - CHAP A1 - Meuser, Martin A1 - Rahimpour, Ebrahim A1 - Eslamian, Morteza T1 - An Inductance Matrix Expansion Method for Transient Analysis of Power Transformer using Single Turn Model T2 - 24th International Symposium on High Voltage Engineering Y1 - 2025 ER - TY - CHAP A1 - Meuser, Martin A1 - Rahimpour, Ebrahim A1 - Eslamian, Morteza T1 - Induktivitätsmatrixerweiterung für die Transientenanalyse in Leistungstransformatoren T2 - 18th Transformer-Life-Management Konferenz Y1 - 2025 ER - TY - JOUR A1 - Gustavsen, B. A1 - Rahimpour, Ebrahim T1 - High-Frequency Transformer and Reactor Models for Network Studies JF - Electra Y1 - 2023 IS - 328 SP - 1 EP - 13 ER -