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



2024

5386.

Ehrhardt, Matthias; Kozitskiy, Sergey B
A generalization of the split-step Padé method to the case of coupled acoustic modes equation in a 3D waveguide
Journal of Sound and Vibration :118304
2024
Herausgeber: Elsevier

5385.

Petrov, Pavel S.; Ehrhardt, Matthias; Kozitskiy, Sergey B.
A generalization of the split-step Padé method to the case of coupled acoustic modes equation in a 3D waveguide
Journal of Sound and Vibration, 577 :118304
2024
Herausgeber: Academic Press

5384.

Petrov, Pavel S.; Ehrhardt, Matthias; Kozitskiy, Sergey B.
A generalization of the split-step Padé method to the case of coupled acoustic modes equation in a 3D waveguide
Journal of Sound and Vibration, 577 :118304
2024
Herausgeber: Academic Press

5383.

Clevenhaus, Anna; Totzeck, Claudia; Ehrhardt, Matthias
A gradient-based calibration method for the Heston model
International Journal of Computer Mathematics, 101 (9-10) :1094–1112
2024
Herausgeber: Taylor & Francis

5382.

Clevenhaus, Anna; Totzeck, Claudia; Ehrhardt, Matthias
A gradient-based calibration method for the Heston model
International Journal of Computer Mathematics, 101 (9-10) :1094–1112
2024
Herausgeber: Taylor & Francis

5381.

Clevenhaus, Anna; Totzeck, Claudia; Ehrhardt, Matthias
A gradient-based calibration method for the Heston model
International Journal of Computer Mathematics
2024

5380.

Khosrawi-Rad, Bijan; Strohmann, Timo; Grogorick, Linda; Robra-Bissantz, Susanne
A Meta-Study on Design Knowledge for Virtual Reality in Collaborative Work
Pacific Asia Conference on Information Systems (PACIS)
Ho Chi Minh City, Vietnam
2024

5379.

Schäfers, Kevin; Peardon, Michael; Günther, Michael
A modified Cayley transform for SU (3)
Preprint
2024

5378.

Schäfers, Kevin; Peardon, Michael; Günther, Michael
A modified Cayley transform for SU (3)
Preprint
2024

5377.

Schaefers, Kevin; Peardon, Michael
A modified Cayley transform for SU(3)
2024

5376.

Carslaw, Nicola; Bekö, Gabriel; Langer, Sarka; Schoemaecker, Coralie; Mihucz, Victor G.; Dudzinska, Marzenna; Wiesen, Peter; Nehr, Sascha; Huttunen, Kati; Querol, Xavier; Shaw, David
A new framework for indoor air chemistry measurements: Towards a better understanding of indoor air pollution
Indoor Environments, 1 (1) :100001
März 2024
ISSN: 29503620

5375.

Ehrhardt, Matthias
A nonstandard finite difference scheme for a time-fractional model of Zika virus transmission
Mathematical Biosciences and Engineering, 21 (1) :924–962
2024
Herausgeber: AIMS Press

5374.

Ehrhardt, Matthias
A nonstandard finite difference scheme for a time-fractional model of Zika virus transmission
Mathematical Biosciences and Engineering, 21 (1) :924–962
2024
Herausgeber: AIMS Press

5373.

Hölz, Julian
A Note on the Uniform Ergodicity of Dynamical Systems.
2024

5372.

Clevenhaus, Anna; Totzeck, Claudia; Ehrhardt, Matthias
A numerical study of the impact of variance boundary conditions for the Heston model
In Burnecki, K. and Szwabiński, J. and Teuerle, M., Editor
Springer
In Burnecki, K. and Szwabiński, J. and Teuerle, M., Editor
Herausgeber: Bergische Universität Wuppertal
2024

5371.

Clevenhaus, Anna; Totzeck, Claudia; Ehrhardt, Matthias
A numerical study of the impact of variance boundary conditions for the Heston model
In Burnecki, K. and Szwabiński, J. and Teuerle, M., Editor
Springer
In Burnecki, K. and Szwabiński, J. and Teuerle, M., Editor
Herausgeber: Bergische Universität Wuppertal
2024

5370.

Clemens, Markus; Henkel, Marvin-Lucas; Kasolis, Fotios; Günther, Michael
A Port-Hamiltonian System Perspective on Electromagneto-Quasistatic Field Formulations of Darwin-Type
Preprint
2024

5369.

Clemens, Markus; Henkel, Marvin-Lucas; Kasolis, Fotios; Günther, Michael
A Port-Hamiltonian System Perspective on Electromagneto-Quasistatic Field Formulations of Darwin-Type
Preprint
2024

5368.

Hoang, Manh Tuan; Ehrhardt, Matthias
A second-order nonstandard finite difference method for a general Rosenzweig-MacArthur predator--prey model
Journal of Computational and Applied Mathematics :115752
2024
Herausgeber: Elsevier

5367.

Dächert, Kerstin; Fleuren, Tino; Klamroth, Kathrin
A simple, efficient and versatile objective space algorithm for multiobjective integer programming
Mathematical Methods of Operations Research, 100 :351—384
2024

5366.

Vinod, Vivin; Zaspel, Peter
Assessing Non-Nested Configurations of Multifidelity Machine Learning for Quantum-Chemical Properties
Machine Learning: Science and Technology, 5 (4) :045005
2024

5365.

Abel, Ulrich; Acu, Ana Maria; Heilmann, Margareta; Raşa, Ioan
Asymptotic expansions for variants of the gamma and Post–Widder operators preserving 1 and x^j
Mathematical Methods in the Applied Sciences, 47 (18) :13718-13733
2024

5364.

Abel, Ulrich; Acu, Ana Maria; Heilmann, Margareta; Raşa, Ioan
Asymptotic properties for a general class of Szász-Mirakjan-Durrmeyer operators
2024

5363.

Bauß, Julius; Stiglmayr, Michael
Augmenting Biobjective Branch & Bound with Scalarization-Based Information
Mathematical Methods of Operations Research
2024

5362.

Vinod, Vivin; Zaspel, Peter
Benchmarking Data Efficiency in Δ-ML and Multifidelity Models for Quantum Chemistry.
2024