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

1979

16.

Barnes, Ian; Becker, Karl Heinz; Fink, Ewald H.
Near-infrared emissions from the \(^{1}\)\(\Delta\)\(_{g}\) and \(^{1}\)\(\Sigma\)\(_{g}\)\(^{+}\) states of S\(_{2}\)
Chemical Physics Letters, 67 (2-3) :314-317
1979

DOI: 10.1016/0009-2614(79)85169-6

15.

Barnes, Ian; Becker, Karl Heinz; Fink, Ewald H.
Near-infrared emissions from the \(^{1}\)\(\Delta\)\(_{g}\) and \(^{1}\)\(\Sigma\)\(_{g}\)\(^{+}\) states of S\(_{2}\)
Chemical Physics Letters, 67 (2-3) :314-317
1979

DOI: 10.1016/0009-2614(79)85169-6

14.

Barnes, Ian; Becker, Karl Heinz; Fink, Ewald H.
Near-infrared emissions from the 1Δg and 1Σg+ states of S2
Chemical Physics Letters, 67 (2-3) :314-317
1979

DOI: 10.1016/0009-2614(79)85169-6

13.

Tausch, Michael W.
Vorschlag für den Aufbau und die Bewertung einer Klausur zum Kurs ''Bindung und Struktur''
Praxis der Naturwissenschaften (Chemie), 28 :304
1979
1978

12.

Tausch, Michael W.; C. Hass, E.; J. Plath, P.
Eine graphentheoretische Bezugsstruktur für die Eigenwertsumme konjugierter Kohlenwasserstoffe
Bremer Briefe zur Chemie, 2 (30)
1978

11.

Leiss, A.; Schurath, Ulrich; Becker, Karl Heinz; Fink, Ewald H.
Revised quenching rate constants for metastable oxygen molecules O\(_{2}\)(a\(^{1}\)\(\Delta\)\(_{g}\))
Journal of Photochemistry, 8 (2) :211-214
1978

DOI: 10.1016/0047-2670(78)80021-5

10.

Leiss, A.; Schurath, Ulrich; Becker, Karl Heinz; Fink, Ewald H.
Revised quenching rate constants for metastable oxygen molecules O\(_{2}\)(a\(^{1}\)\(\Delta\)\(_{g}\))
Journal of Photochemistry, 8 (2) :211-214
1978

DOI: 10.1016/0047-2670(78)80021-5

9.

Leiss, A.; Schurath, Ulrich; Becker, Karl Heinz; Fink, Ewald H.
Revised quenching rate constants for metastable oxygen molecules O2(a1Δg)
Journal of Photochemistry, 8 (2) :211-214
1978

DOI: 10.1016/0047-2670(78)80021-5

1977

8.

[german] Tausch, Michael W.; Elian, Mihai; Bucur, Aurora; Cior{{\^a}}nescu, Ecaterina
Über das photochemische Verhalten von zwei Tribenzo-(CH)12-Valenzisomeren
Chemische Berichte, 110 (5) :1744-1747
1977
Herausgeber: Wiley

DOI: 10.1002/cber.19771100518

1974

7.

Mihail, R.; Tausch, Michael W.
Homogene Reaktionen in einem Rohrreaktor mit nicht-Newtonscher Strömung
The Chemical Engineering Journal, 7 (1) :53--60
1974
Herausgeber: Elsevier {BV}

DOI: 10.1016/0300-9467(74)80025-0

6.

Becker, Karl Heinz; Fink, Ewald H.; Langen, P.; Schurath, Ulrich
Near infrared emission bands of the HO\(_{2}\) radical
The Journal of Chemical Physics, 60 (11) :4623-4625
1974

DOI: 10.1063/1.1680950

5.

Becker, Karl Heinz; Fink, Ewald H.; Langen, P.; Schurath, Ulrich
Near infrared emission bands of the HO\(_{2}\) radical
The Journal of Chemical Physics, 60 (11) :4623-4625
1974

DOI: 10.1063/1.1680950

4.

Becker, Karl Heinz; Fink, Ewald H.; Langen, P.; Schurath, Ulrich
Near infrared emission bands of the HO2 radical
The Journal of Chemical Physics, 60 (11) :4623-4625
1974

DOI: 10.1063/1.1680950

1973

3.

Becker, Karl Heinz; Fink, Ewald H.; Langen, P.; Schurath, Ulrich
The Chemiluminescent Reaction of HCO with O\(_{2}\)(\(^{1}\)\(\Delta\)\(_{g}\))
Zeitschrift für Naturforschung A, 28 (11) :1872-1874
1973

DOI: 10.1515/zna-1973-1121

2.

Becker, Karl Heinz; Fink, Ewald H.; Langen, P.; Schurath, Ulrich
The Chemiluminescent Reaction of HCO with O\(_{2}\)(\(^{1}\)\(\Delta\)\(_{g}\))
Zeitschrift für Naturforschung A, 28 (11) :1872-1874
1973

DOI: 10.1515/zna-1973-1121

1.

Becker, Karl Heinz; Fink, Ewald H.; Langen, P.; Schurath, Ulrich
The Chemiluminescent Reaction of HCO with O2(1Δg)
Zeitschrift für Naturforschung A, 28 (11) :1872-1874
1973

DOI: 10.1515/zna-1973-1121