TY - CHAP A1 - Schmitt, Maximilian A1 - Ackva, Ansgar T1 - A Novel Control Strategy for Reducing Common-Mode Currents in Bidirectional Drive Systems T2 - 20th European Conference on Power Electronics and Applications (EPE’18 ECCE Europe) Y1 - 2018 SN - 9781538641453 SP - 1 EP - 9 PB - IEEE ER - TY - JOUR A1 - Ziegler, Andreas A1 - Oeser, David A1 - Hein, Thiemo A1 - Montesinos Miracle, Daniel A1 - Ackva, Ansgar T1 - Reducing Cell to Cell Variation of Lithium-Ion Battery Packs During Operation Y1 - 2021 U6 - https://doi.org/10.1109/ACCESS.2021.3057125 VL - 9 SP - 24994 EP - 25001 ER - TY - JOUR A1 - Ziegler, Andreas A1 - Oeser, David A1 - Hein, Thiemo A1 - Montesinos Miracle, Daniel A1 - Ackva, Ansgar T1 - Run to Failure: Aging of Commercial Battery Cells beyond Their End of Life JF - Energies Y1 - 2020 U6 - https://doi.org/10.3390/en13081858 VL - 13 IS - 8 ER - TY - CHAP A1 - Raab, Sebastian A1 - Hofmann, Martin A1 - Kasten, Henning A1 - Ackva, Ansgar T1 - High Bandwidth PWM-based Amplifier for Non-Linear Hybrid Filter in Electric Vehicle DC Grids T2 - 25th European Conference on Power Electronics and Applications (EPE'23 ECCE Europe) N2 - The paper presents design and modulation strategy for a high bandwidth PWM-based amplifier. It consists of multiple H-bridges connected in parallel and switched sequentially. As the effective switching frequency is a multiple of the switching frequency of each single switch, the bandwidth is scaled by the number of H-bridges in parallel. The prototype presented supports a maximum number of eight H-bridges in parallel. Y1 - 2023 SN - 978-9-0758-1541-2 U6 - https://doi.org/10.23919/EPE23ECCEEurope58414.2023.10264683 SP - 1 EP - 9 PB - IEEE ER - TY - CHAP A1 - Raab, Sebastian A1 - Ackva, Ansgar T1 - Non-linear hybrid filter for the DC-side ripple current of voltage source converters T2 - 2022 International Symposium on Electromagnetic Compatibility – EMC Europe N2 - The paper deals with the design of DC-side filters for three-phase voltage source converters of drives connected to an industrial or automotive DC-grid. It points out the problem of designing a filter if the DC-grid impedance and structure are unknown. Therefore, it presents a new non-linear hybrid filter whose filter effect is less dependent on the impedance of the downstream DC-grid and with better immunity against external interferences. The analytical and simulation based design process is explained with help of a concrete example. Results are validated by measurements on an experimental set-up. Y1 - 2022 SN - 978-1-6654-0788-5 U6 - https://doi.org/10.1109/emceurope51680.2022.9901278 SN - 2325-0364 PB - IEEE ER - TY - CHAP A1 - Kempkes, Joachim A1 - Wolz, Christoph A1 - Ackva, Ansgar A1 - Schäfer, Uwe T1 - Nichtlineare Berechnung von permanentmagneterregten Gleichstrommotoren mit konzentrierten Wicklungen BT - Antriebssysteme 2013: Elektrik, Mechanik und Hydraulik in der Anwendung T2 - Vorträge der 4. VDE/VDI-Tagung vom 17. bis 18. September 2013 in Nürtingen Y1 - 2013 PB - VDE CY - Berlin ER - TY - JOUR A1 - Oeser, David A1 - Hein, Thiemo A1 - Ziegler, Andreas A1 - Seefried, Michael A1 - Gielinger, Sebastian A1 - Montesinos-Miracle, Daniel A1 - Bohn, Gunther A1 - Ackva, Ansgar T1 - Age-related development of cell-to-cell variation under various operating conditions in commercial NMC/graphite lithium-ion cells JF - Journal of Energy Storage N2 - In real applications, lithium-ion cells are usually used in individual interconnections, with the worst cell determining capacity, performance and service life. Due to different ageing rates of the assembled cells, cell-to-cell variation changes over lifetime. In literature, cell-to-cell variation is usually investigated near room temperature under one operating condition. Data regarding cell-to-cell variation above and below room temperature under different operating conditions are hard to find. To fill the gap in literature, this study considers cell-to-cell variation as a function of different charge/discharge currents at ambient temperatures between 0 °C and 40 °C on commercial NMC/graphite cells (Samsung SDI ICR18650-26J). The results demonstrate that cell-to-cell variation strongly depends on the selected operating conditions. In particular, operating conditions near the lithium plating boundary at the beginning of the ageing process have a particularly high risk of developing a pronounced variation. Fast charging or charging at lower temperatures should therefore be avoided. Operation at moderate temperatures and currents, on the other hand, only leads to a slight increase in cell-to-cell variation in the tests carried out. A 24-month storage during the testing period at 30% SOC and room temperature of the same cells shows even a slight reduction in cell-to-cell variation. Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:863-opus-57585 VL - 101 PB - Elsevier ER - TY - JOUR A1 - Ackva, Ansgar A1 - Dreßel, Bernd A1 - Endres, Julian T1 - Umrichter in Hybridstruktur als Entwicklungswerkzeug und Prüfsystem für elektrische Antriebe JF - FHWS Science Journal N2 - Die Entwicklung, Applikation und der Test von Wechselrichtern, insbesondere für Traktionsantriebe, ist mit einem hohen Aufwand für die Bereitstellung einer passenden Testumgebung verbunden. Für gewöhnlich werden diese Tests in der Entwicklung als auch in der Fertigung mit Hilfe von Motor-Generator Prüfständen durchgeführt, die wiederum für unterschiedliche Leistungsklassen vorgehalten werden müssen. In diesem Beitrag wird eine neuartige hochdynamische Umrichtertopologie vorgestellt, die als universelles Entwicklungs-, Applikations- und Prüfsystem für Umrichter eingesetzt werden kann. Derzeit wird dieser Umrichter in Hybridstruktur im Rahmen eines Forschungsprojektes an der FHWS realisiert. KW - Electromobility KW - Energy Engineering Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:863-opus-484 VL - 1 IS - 2 SP - 25 EP - 36 CY - Würzburg 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 -