Applied and Computational Mathematics (ACM)

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

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

Cooperation

Former and ongoing projects

Publications



2026

5588.

Abel, Ulrich; Acu, Ana-Maria; Heilmann, Margareta; Raşa, Ioan
Genuine Bernstein-Durrmeyer operators preserving 1 and x^j (II)
Approximation Theory and Special Functions, Seite 97--112
ATSF 2024
Ankara, Turkey
Herausgeber: Springer Nature Switzerland
2026

ISBN: 978-3-031-93279-3

5587.

Vinod, Vivin; Zaspel, Peter
Improvise, Adapt, Overcome: An On-The-Fly Multifidelity Algorithm for Efficient Machine Learning
2026

5586.

Abel, Ulrich; Acu, Ana Maria; Heilmann, Margareta; Raşa, Ioan
Kernels for composition of positive linear operators
Journal of Mathematical Analysis and Applications, 555 (2) :130052
2026
ISSN: 0022-247X

5585.

Zeller, Diana; Bohrmann-Linde, Claudia
KI-Chatbots als Unterrichtswerkzeug: Eine Lehrkräftefortbildung zum Einsatz von KI-Chatbots im Chemieunterricht
CHEMKON, 33/3 :71-76
2026

5584.

Abel, Ulrich; Acu, Ana-Maria; Heilmann, Margareta; Raşa, Ioan
Korovkin type theorems for operators acting on functions of polynomial and exponential growth on $[0,ınfty)$
2026

5583.

Abel, Ulrich; Acu, Ana-Maria; Heilmann, Margareta; Raşa, Ioan
Korovkin type theorems for operators acting on functions of polynomial and exponential growth on $[0,ınfty)$
2026

5582.

Vinod, Vivin; Zaspel, Peter
LFaB: Low Fidelity as Bias for Active Learning in the Chemical Configuration Space
J. Chem. Theory Comput., 22 (11) :5637-5648
2026

5581.

Könen, David; Stiglmayr, Michael
Output-sensitive Complexity of Multi-Objective Integer Network Flow Problems
Journal of Combinatorial Optimization, 51 (14)
2026

5580.

Yuden, Kezang; Nemesch, Levin; Ruzika, Stefan
Parametric Biobjective Linear Programming
2026

5579.

Abel, Ulrich; Acu, Ana-Maria; Heilmann, Margareta; Raşa, Ioan
Positive linear operators fixing two prescribed functions
2026

5578.

Lopes, Gonçalo; Klamroth, Kathrin; Paquete, Luís
Solving hypervolume scalarizations for MOCO problems
2026

5577.

Schaub, Louise; Zaspel, Peter
Variational Free Energy Pivot Selection for Pivoted Cholesky
arXiv preprint
2026

5576.

Acu, A.M.; Heilmann, Margareta; Raşa, I.
Convergence of linking Durrmeyer type modifications of generalized Baskatov operators
Bulleting of the Malaysian Math. Sciences Society

5575.

Ehrhardt, Matthias
Ein einfaches Kompartment-Modell zur Beschreibung von Revolutionen am Beispiel des Arabischen Frühlings

5574.

Günther, Michael
Einführung in die Finanzmathematik

5573.

Al{\i}, G; Bartel, A
Electrical RLC networks and diodes

5572.

Gjonaj, Erion; Bahls, Christian Rüdiger; Bandlow, Bastian; Bartel, Andreas; Baumanns, Sascha; Belzen, F; Benderskaya, Galina; Benner, Peter; Beurden, MC; Blaszczyk, Andreas; others
Feldmann, Uwe, 143 Feng, Lihong, 515 De Gersem, Herbert, 341 Gim, Sebasti{\'a}n, 45, 333
MATHEMATICS IN INDUSTRY 14 :587

5571.

Ehrhardt, Matthias
für Angewandte Analysis und Stochastik

5570.

Ehrhardt, Matthias; Günther, Michael; Striebel, Michael
Geometric Numerical Integration Structure-Preserving Algorithms for Lattice QCD Simulations

5569.


High order tensor product interpolation in the Combination Technique
preprint, 14 :25

5568.

Hendricks, Christian; Ehrhardt, Matthias; Günther, Michael
Hybrid finite difference/pseudospectral methods for stochastic volatility models
19th European Conference on Mathematics for Industry, Seite 388

5567.

Ehrhardt, Matthias; Csomós, Petra; Faragó, István; others
Invited Papers

5566.

Günther, Michael
Lab Exercises for Numerical Analysis and Simulation I: ODEs

5565.

Ehrhardt, Matthias; Günther, Michael
Mathematical Modelling of Dengue Fever Epidemics

5564.

Ehrhardt, Matthias
Mathematical Modelling of Monkeypox Epidemics