Computational Magnetics
Many electro-technical devices such as e.g. printed circuit boards, electrical drives and antenna systems can be simulated on the basis of electrical circuits. However, the increasing frequencies and the decreasing size force designers to account for wave propagation effects, eddy-current effects, ferromagnetic saturation and hysteresis. For wave propagation effects and eddy-current effects, the results of stand-alone field simulation can be represented by an order-reduced equivalent model, which is then inserted in the overall circuit model. The representation of field-dependent nonlinearities and hysteresis effects, however, is not straightforward.

2D Simulation of a Transformer
The coupled field and circuit simulation becomes troublesome when a large number of time steps is required. This occurs when e.g. simulating an electrical drive where the machine requires 10 periods of 50 Hz to reach nominal speed whereas the switching of the Insulated Gate Bipolar Transistors in the frequency converter switches at 20 kHz, necessitating a time steps in the order of a microsecond to be used in the simulation. Since the field model consists typically of a few million degrees of freedom, all those unknowns have to be solved in every time step. Fortunately, the relevant time constants in electrical-energy converter are in the range 50 Hz. Hence the field model does not have to be time-stepped at the same rate as the circuit model, in which fast switches are present. The use of adaptive multirate time-integration schemes can reduce the numerical complexity of the problem substantially.
Research Questions
- Efficiency of the time-integration for field devices in pulsed circuits (multirate, dynamic iteration)
- DAE-index of the coupled system
- Existence and Uniqueness of the solution
Cooperation
- Herbert De Gersem, Katholieke Universiteit Leuven
- Markus Clemens, Bergische Universität Wuppertal
- Sascha Baumanns, Universität zu Köln
Former and ongoing projects
Publications
- 2022
4841.
Lugo, Pedro L.; Straccia, V.G.; Rivela, Cynthia B.; Patroescu-Klotz, Iulia; Illmann, Niklas; Teruel, Mariano A.; Wiesen, Peter; Blanco, María B.
Diurnal photodegradation of fluorinated diketones (FDKs) by OH radicals using different atmospheric simulation chambers: Role of keto-enol tautomerization on reactivity
Chemosphere, 286 :131562
Januar 2022
ISSN: 004565354840.
Rohde, Martin; Barwari, Beawer; Burgmann, Sebastian; Janoske, Uwe
Droplet motion induced by superposition of shear flow and horizontal surface vibration
International Journal of Multiphase Flow, 155 :104163
2022
Herausgeber: Pergamon4839.
McWalter, Thomas A; Kienitz, Jörg; Nowaczyk, Nikolai; Rudd, Ralph; Acar, Sarp K.
Dynamic initial margin estimation based on quantiles of Johnson distributions
Journal of Credit Risk, 18 :93–116
2022
Herausgeber: Incisive Media4838.
Kienitz, Jörg; Lee, Gordon; Nowaczyk, Nikolai; Geng, N.
Dynamically controlled kernel estimation
Risk Cutting Edge, 1
2022
Herausgeber: Incisive Media4837.
Kienitz, J.; Lee, G.; Nowaczyk, N.; Geng, N.
Dynamically Controlled Kernel Estimation
RISK, 1
20224836.
Felpel, Mike; Kienitz, Jörg; McWalter, Thomas
Effective Markovian projection: Application to CMS spread options and mid-curve swaptions
Quantitative Finance, 22 (6) :1169–1192
2022
Herausgeber: Routledge4835.
Felpel, M.; Kienitz, J.; McWalter, T. A.
Effective Markovian projection: application to CMS spread options and mid-curve swaptions
Quantitative Finance, 22 (6) :1169-1192
2022
Herausgeber: Routledge4834.
Reiners, Malena; Klamroth, Kathrin; Heldmann, Fabian; Stiglmayr, Michael
Efficient and sparse neural networks by pruning weights in a multiobjective learning approach
Computers & Operations Research :105676
20224833.
[german] Cornelius, Soraya; Bohrmann-Linde, Claudia
Einsatz eines digitalen & interaktiven Selbstlernbuchs zur Einführung in die organische Chemie - erste Erprobungen im Chemieunterricht und motivationale Betrachtungen
Chemie & Schule, 2022 (4) :5-9
20224832.
Clemens, Markus; Henkel, Marvin-Lucas; Kasolis, Fotios; Günther, Michael; De Gersem, Herbert; Schöps, Sebastian
Electromagnetic Quasistatic Field Formulations of Darwin Type
arXiv preprint arXiv:2204.06286
20224831.
Clemens, Markus; Henkel, Marvin-Lucas; Kasolis, Fotios; Günther, Michael; De Gersem, Herbert; Schöps, Sebastian
Electromagnetic quasistatic field formulations of Darwin type
Preprint :1–7
20224830.
Clemens, Markus; Henkel, Marvin-Lucas; Kasolis, Fotios; Günther, Michael; De Gersem, Herbert; Schöps, Sebastian
Electromagnetic quasistatic field formulations of Darwin type
Preprint :1–7
20224829.
Schillings, Claudia; Totzeck, Claudia; Wacker, Philipp
Ensemble-based gradient inference for particle methods in optimization and sampling
20224828.
Lübke, Steffen
Entwicklung und Optimierung einer kleintechnischen Anlage zur Behandlung galvanischer Abwässer mittels Aersolbasierter Eliminierung (ABE)
20224827.
Gaul, Daniela; Klamroth, Kathrin; Stiglmayr, Michael
Event-based MILP models for ridepooling applications
European Journal of Operational Research, 301 :1048-1063
20224826.
Glück, Jochen
Evolution equations with eventually positive solutions
Eur. Math. Soc. Mag. (123) :4--11
20224825.
Halffmann, Pascal; Schäfer, Luca E.; Dächert, Kerstin; Klamroth, Kathrin; Ruzika, Stefan
Exact algorithms for multiobjective linear optimization problems with integer variables - a state of the art survey
Journal of Multicriteria Decision Analysis, 29 :343–363
20224824.
Kalalian, Carmen; Grira, Asma; Illmann, Jan Niklas; Patroescu-Klotz, Iulia; El Dib, Gisèle; Coddeville, Patrice; Canosa, André; Wiesen, Peter; Aazaad, Basheer; Senthilkumar, Lakshmipathi; Roth, Estelle; Tomas, Alexandre; Chakir, Abdelkhaleq
Experimental and Theoretical Studies of Trans-2-Pentenal Atmospheric Ozonolysis
Atmosphere, 13 (2) :291
Februar 2022
ISSN: 2073-44334823.
Braschke, Kamil Oskar; Zoller, Julian; Freese, Florian; Dittler, Achim; Janoske, Uwe
Fast adhesion calculation for collisions between arbitrarily shaped particles and a wall
Powder Technology, 405 :117494
2022
ISSN: 0032-59104822.
Farkas, Bálint; Nagy, Béla; Révész, Szilárd Gy.
Fenton type minimax problems for sum of translates functions
20224821.
Könen, David; Schmidt, Daniel; Spisla, Christiane
Finding all minimum cost flows and a faster algorithm for the K best flow problem
Discrete Applied Mathematics, 321 :333-349
2022
ISSN: 0166-218X4820.
Hensel, Hendrik; Henkel, Marvin-Lucas; Haussmann, Norman; Jörgens, Christoph; Stroka, Steven; Clemens, Markus
GPU-Accelerated Field Simulation of HVAC Gas Insulated Lines
2022 IEEE 20th Biennial Conference on Electromagnetic Field Computation (CEFC), Seite 1-2
20224819.
Teng, Long
Gradient boosting-based numerical methods for high dimensional backward stochastic differential equations
Appl. Math. Comput., 426 :127119
20224818.
Teng, Long
Gradient boosting-based numerical methods for high-dimensional backward stochastic differential equations
Applied Mathematics and Computation, 426 :127119
2022
Herausgeber: Elsevier4817.
[german] Zeller, Diana
Heimische Ökosysteme erkunden. Mit Maphub kooperative, ökologische Kartierung umsetzen.
Digital Unterricht Biologie, 1 (1/2022) :10-11
Januar 2022