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



2020

4217.

Arendt, Wolfgang; ter Elst, Antonius F. M.; Glück, Jochen
Strict positivity for the principal eigenfunction of elliptic operators with various boundary conditions
Adv. Nonlinear Stud., 20 (3) :633--650
2020

4216.

Acu, Ana-Maria; Heilmann, Margareta; Raşa, Ioan
Strong converse results for linking operators and convex functions
Journal of Function Spaces, 2020 (1) :4049167
2020

4215.

Bunker, P. R.; Jensen, Per
The Planck constant of action h\(_{A}\)
Journal of Quantitative Spectroscopy and Radiative Transfer
2020

4214.

Bunker, P. R.; Jensen, Per
The Planck constant of action h\(_{A}\)
Journal of Quantitative Spectroscopy and Radiative Transfer
2020

4213.

Bunker, P. R.; Jensen, Per
The Planck constant of action hA
Journal of Quantitative Spectroscopy and Radiative Transfer
2020

4212.

Kreidler, Henrik
The primitive spectrum of a semigroup of {M}arkov operators
Positivity, 24 (2) :287--312
2020

4211.

Kreidler, Henrik
The primitive spectrum of a semigroup of Markov operators
Positivity, 24 (2) :287--312
2020

4210.

Farkas, Bálint; Kreidler, Henrik
Towards a Koopman theory for dynamical systems on completely regular spaces
Phil. Trans. Royal Soc. A, 378
2020

4209.

Günther, Christoph; Günther, Michael; Günther, Daniel
Tracing contacts to control the COVID-19 pandemic
Preprint
2020

4208.

Günther, Christoph; Günther, Michael; Günther, Daniel
Tracing contacts to control the COVID-19 pandemic
arXiv preprint arXiv:2004.00517
2020

4207.

Günther, Christoph; Günther, Michael; Günther, Daniel
Tracing contacts to control the COVID-19 pandemic
Preprint
2020

4206.


Transparent boundary conditions for the sine-Gordon equation
2020

4205.

Ehrhardt, Matthias
Valuation of basket credit default swaps under stochastic default intensity models
Advances in Applied Mathematics and Mechanics, 12 (5) :1301–1326
2020
Herausgeber: Global Science Press

4204.

Ehrhardt, Matthias
Valuation of basket credit default swaps under stochastic default intensity models
Advances in Applied Mathematics and Mechanics, 12 (5) :1301–1326
2020
Herausgeber: Global Science Press

4203.

Ehrhardt, Matthias
Valuation of basket credit default swaps under stochastic default intensity models
Advances in Applied Mathematics and Mechanics, 12 (5) :1301--1326
2020
Herausgeber: Global Science Press

4202.

Tausch, Michael W.
Videoclip oder Realexperiment?
Nachrichten aus der Chemie, 68 (6-7) :18-19
2020

4201.

Skrepek, Nathanael
Well-posedness of linear first order Port-Hamiltonian Systems on multidimensional spatial domains
Evolution Equation \& Control Theory
2020

4200.

Ehrhardt, Matthias
Wide-angle mode parabolic equations for the modelling of horizontal refraction in underwater acoustics and their numerical solution on unbounded domains
Journal of Sound and Vibration, 484 :115526
2020
Herausgeber: Academic Press

4199.

Ehrhardt, Matthias
Wide-angle mode parabolic equations for the modelling of horizontal refraction in underwater acoustics and their numerical solution on unbounded domains
Journal of Sound and Vibration, 484 :115526
2020
Herausgeber: Academic Press

4198.

Ehrhardt, Matthias
Wide-angle mode parabolic equations for the modelling of horizontal refraction in underwater acoustics and their numerical solution on unbounded domains
Journal of Sound and Vibration, 484 :115526
2020
Herausgeber: Academic Press
2019

4197.

Yildiz, Deniz; Baumann, Christoph; Mikosch, Annabel; Kuehne, Alexander J. C.; Herrmann, Andreas; Göstl, Robert
Anti-Stokes Stress Sensing: Mechanochemical Activation of Triplet–Triplet Annihilation Photon Upconversion
Angewandte Chemie International Edition, 58 (37) :12919-12923
September 2019
ISSN: 1521-3773

4196.

Yildiz, Deniz; Baumann, Christoph; Mikosch, Annabel; Kuehne, Alexander J. C.; Herrmann, Andreas; Göstl, Robert
Anti-Stokes-Belastungsanzeige: Mechanochemische Aktivierung der Triplett-Triplett-Annihilierung-Photonen-Hochkonversion
Angewandte Chemie, 131 (37) :13051-13055
September 2019
ISSN: 1521-3757

4195.

Jensen, Per
Linear and bent triatomic molecules are not qualitatively different!
Canadian Journal of Physics
August 2019

4194.

Jensen, Per
Linear and bent triatomic molecules are not qualitatively different!
Canadian Journal of Physics :1-6
August 2019
Herausgeber: NRC Research Press

4193.

Jensen, Per
Linear and bent triatomic molecules are not qualitatively different!
Canadian Journal of Physics :1-6
August 2019
Herausgeber: NRC Research Press