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Development and experimental parameterization of an MHD switching arc model for low-voltage DC contactors
2026
Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2026
Veröffentlicht auf dem Publikationsserver der RWTH Aachen University
Genehmigende Fakultät
Fak06
Hauptberichter/Gutachter
;
Tag der mündlichen Prüfung/Habilitation
2026-05-29
Online
DOI: 10.18154/RWTH-2026-06647
URL: https://publications.rwth-aachen.de/record/1038635/files/1038635.pdf
Einrichtungen
Thematische Einordnung (Klassifikation)
DDC: 621.3
Kurzfassung
One key factor for widespread adoption of battery electric vehicles (BEVs) is the reduction of charging times without compromising driving range. To meet this demand, higher battery voltages are being used. However, increasing the battery voltage imposes greater demands on protective equipment, particularly with regard to the switching solution, which must be capable of interrupting fault currents at these higher voltages. In the case of a mechanical direct current (DC) contactor with contact bridge design (CBD)—a typical switching solution in BEVs—the device must be able to extinguish the arc that forms during a switching operation at these higher voltages. Numerical arc models are developed to gain insights into arc behavior. These models enable the prediction of arc behavior, thereby reducing the need for experimental evaluation of every design iteration. Consequently, only a limited number of key designs are experimentally investigated to assess performance and validate the model. Magnetohydrodynamics (MHD) provides the foundation for the arc models by combining the principles of fluid dynamics and electromagnetism. However, because MHD arc models rely on empirical input data parameterized through experiments, they must be parameterized and validated for each individual switch operating principle. Previous works have focused on modeling switching arcs in alternating current (AC) switches for various switch designs and operating principles. Thus, the applicability of these existing parameterizations to DC contactors with CBD remains unknown. The main goal of this doctoral thesis is to develop a parameterization for an MHD arc model for a DC contactor with CBD. To achieve this, first, the influencing factors of the arc extinguishing process within the CBD are identified and implemented as modeling aspects into the MHD arc model. In order to parameterize and validate these modeling aspects, three experimental arc investigation setups are developed. These setups aim to systematically examine the effects of specific influencing factors while minimizing the impact of other influences. The experimental data obtained from these setups is used to parameterize and validate their corresponding arc models. Finally, the validated modeling aspects are integrated into the MHD arc model for the DC contactor with CBD, and its simulation results are evaluated by comparing it against an exemplary experimental result. The first contribution of this thesis is data obtained from experimental DC arc studies performed in three experimental arc investigation setups. This data enhances understanding of DC arc phenomena and serves to validate modeling aspects of MHD arc models. With this data, existing parameterizations of AC arc models are validated for DC arc scenarios. A key finding of this investigation is that AC parameterizations can be effectively utilized in modeling DC arcs. The findings contribute to a more robust framework for simulating arcs, potentially improving the predictive capabilities of MHD simulations. The second contribution are boundary conditions for modeling polyamide 6.6 (PA6.6) ablation in MHD arc simulations. These boundary conditions are developed based on the material properties of PA6.6—a material commonly used in low-voltage switchgear such as DC contactors with CBD. Key outcome are the values for the effective ablation enthalpy and band limits for thermal radiation modeling. The boundary conditions have been compared and validated through experimental studies. These findings enhance the modeling accuracy for PA6.6 ablation compared to previous approaches. The third contribution is an MHD arc model for DC contactors featuring a CBD. The key outcome is the model parameterization, allowing the simulation of arc interruption in the CBD. The developed model enables the possibility of predicting the arc behavior, thereby facilitating the design process by reducing the necessity for experimental evaluation of every design iteration. Overall, this contribution extends knowledge regarding the modeling of DC arc behavior and provides insights into modeling strategies for contactor systems with CBD. Overall, findings of this doctoral thesis increase the knowledge of direct current arc phenomena, provide experimental study data for arc model validation, and provide an approach for modeling direct current arc interruption in a contactor featuring a contact bridge design.
OpenAccess: 
PDF
(additional files)
Dokumenttyp
Dissertation / PhD Thesis
Format
online
Sprache
English
Externe Identnummern
HBZ: HT031551361
Interne Identnummern
RWTH-2026-06647
Datensatz-ID: 1038635
Beteiligte Länder
Germany
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