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



2019

4018.

Jacob, Birgit; Wegner, Sven-Ake
Well-posedness of a class of hyperbolic partial differential equations on the semi-axis
J. Evol. Equ., 19 (4) :1111--1147
2019

4017.

Jacob, Birgit; Kaiser, Julia T.
Well-posedness of systems of 1-{D} hyperbolic partial differential equations
J. Evol. Equ., 19 (1) :91--109
2019

4016.

Jacob, Birgit; Kaiser, Julia T.
Well-posedness of systems of 1-D hyperbolic partial differential equations
J. Evol. Equ., 19 (1) :91--109
2019

4015.

Ehrhardt, Matthias
Wide-angle mode parabolic equation with transparent boundary conditions and its applications in shallow water acoustics
2019 Days on Diffraction (DD), Seite 221–225
IEEE
Herausgeber: IEEE
2019

4014.

Ehrhardt, Matthias
Wide-angle mode parabolic equation with transparent boundary conditions and its applications in shallow water acoustics
2019 Days on Diffraction (DD), Seite 221--225
IEEE
2019

4013.

Ehrhardt, Matthias
Wide-angle mode parabolic equation with transparent boundary conditions and its applications in shallow water acoustics
2019 Days on Diffraction (DD), Seite 221–225
IEEE
Herausgeber: IEEE
2019

4012.

Cuny, Christophe; Eisner, Tanja; Farkas, Bálint
Wiener's lemma along primes and other subsequences
Advances in Mathematics, 347 :340 - 383
2019

4011.

Eckardt, Linda; Jankoviak, Adam; Robra-Bissantz, Susanne
Wollen Studierende in einer virtuellen Realität lernen? - Ein vergleichendes Meinungsbild
Seite 89-95
Teaching Trends
Braunschweig
2019

ISBN: 9783830940128

4010.

Jacob, Birgit; Morris, Kirsten A.; Zwart, Hans
Zero dynamics for networks of waves
Automatica J. IFAC, 103 :310--321
2019
2018

4009.

Biallas, Phillip; Heider, Janina; Kirsch, Stefan F.
Functional polyamides with gem-diazido units: synthesis and diversification
Polymer Chemistry, 10 (1) :60–64
Dezember 2018
ISSN: 1759-9962

4008.

Teng, Long; Ehrhardt, Matthias; G\"unther, Michael
Quant} Pricing in Stochastic Correlation Models
IJTAF, 21 (5) (05)
August 2018

4007.

Sharma, M. K.; Göstl, Robert; Frijns, A. J. H.; Wieringa, F. P.; Kooman, J. P.; Sijbesma, R. P.; Smeulders, D. M. J.
A Fluorescent Micro-Optofluidic Sensor for In-Line Ion Selective Electrolyte Monitoring
IEEE Sensors Journal, 18 (10) :3946--3951
Mai 2018
ISSN: 1530-437X

4006.

Holzschneider, Kristina; Kirsch, Stefan F.
[1,2]-Migration Reactions Catalyzed by Gold Complexes and their Applications in Total Synthesis
Israel Journal of Chemistry, 58 (5) :596–607
2018
ISSN: 1869-5868

4005.

Jacob, Birgit; Partington, Jonathan R.; Pott, Sandra; Wynn, Andrew
{\(\beta\)}-admissibility of observation operators for hypercontractive semigroups
J. Evol. Equ., 18 (1) :153--170
2018

4004.

Jacob, Birgit; Partington, Jonathan R.; Pott, Sandra; Wynn, Andrew
β-admissibility of observation operators for hypercontractive semigroups
J. Evol. Equ., 18 (1) :153--170
2018

4003.

Daners, Daniel; Glück, Jochen
A criterion for the uniform eventual positivity of operator semigroups
Integral Equations Operator Theory, 90 (4) :Paper No. 46, 19
2018

4002.

Farkas, Bálint; Nagy, Béla; Révész, Szilárd Gy.
A minimax problem for sums of translates on the torus
Transactions of the London Mathematical Society, 5 (1) :1-46
2018

4001.

Kossaczky, Igor; Ehrhardt, Matthias; Günther, Michael
A new convergent explicit tree-grid method for HJB equations in one space dimension
Numerical Mathematics: Theory, Methods and Applications, 11 (1) :1–29
2018
Herausgeber: Global Science Press

4000.

Ehrhardt, Matthias; Günther, Michael
A new convergent explicit Tree-Grid method for HJB equations in one space dimension
Preprint, 17 (06)
2018

3999.

Kossaczky, Igor; Ehrhardt, Matthias; Günther, Michael
A new convergent explicit tree-grid method for HJB equations in one space dimension
Numerical Mathematics: Theory, Methods and Applications, 11 (1) :1–29
2018
Herausgeber: Global Science Press

3998.

Kossaczky, Igor; Ehrhardt, Matthias; Günther, Michael
A new convergent explicit tree-grid method for HJB equations in one space dimension
Numerical Mathematics: Theory, Methods and Applications, 11 (1) :1–29
2018
Herausgeber: Global Science Press

3997.

Heilmann, Margareta; Raşa, Ioan
A nice representation for a link between Baskakov-and Szász–Mirakjan–Durrmeyer operators and their kantorovich variants
Results in Mathematics, 74 (1) :9
2018

3996.

Glück, Jochen
A note on lattice ordered $C^*$-algebras and Perron-Frobenius theory
Math. Nachr., 291 (11-12) :1727--1732
2018

3995.

Bartel, Andreas; Ehrhardt, Matthias
A numerical tool for the study of the hydrodynamic recovery of the lattice Boltzmann Method
Computers & Fluids, 172 :241–250
2018
Herausgeber: Pergamon

3994.

Bartel, Andreas; Ehrhardt, Matthias
A numerical tool for the study of the hydrodynamic recovery of the Lattice Boltzmann Method
Computers & Fluids, 172 :241--250
2018
Herausgeber: Pergamon