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



1988

225.

Jensen, Per
Calculation of rotation-vibration linestrengths for triatomic molecules using a variational approach
Journal of Molecular Spectroscopy, 132 (2) :429-457
1988

224.

Heilmann, Margareta
Commutativity of operators from Baskakov-Durrmeyer type
Constructive Theory of Functions - Proceedings of the International Conference, Varna, Bulgaria, 1987, Seite 197-206
1988

223.

[german] Tausch, Michael W.; Paterkiewicz, D.
Fluoreszenz und Phosphoreszenz
Praxis der Naturwissenschaften (Chemie), 36 :14
1988

222.

Jensen, Per
Hamiltonians for the internal dynamics of triatomic molecules
Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics, 84 (9) :1315-1339
1988

221.

Jensen, Per
Hamiltonians for the internal dynamics of triatomic molecules
Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics, 84 (9) :1315-1339
1988

220.

Jensen, Per
Hamiltonians for the internal dynamics of triatomic molecules
Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics, 84 (9) :1315-1339
1988

219.

Czech, C. M.; Kling, H.-W.; Hartkamp, H.
Kontinuierliche Derivatisierung von schwerflüchtigen Wasserinhaltsstoffen durch Periodat-Oxidation in Verbindung mit dem Contistrip-Verfahren
Fresenius' Journal of Analytical Chemistry, 332 (4) :341--344
1988

218.

Wildt, J{ü}rgen; Bednarek, G.; Fink, Ewald H.; Wayne, Richard P.
Laser excitation of O\(_{2}\)(b\(^{1}\)\(\Sigma\)\(_{g}\)\(^{+}\), v'=0,1,2) - rates and channels of energy transfer and quenching
Chemical Physics, 122 (3) :463-470
1988

217.

Wildt, J{ü}rgen; Bednarek, G.; Fink, Ewald H.; Wayne, Richard P.
Laser excitation of O\(_{2}\)(b\(^{1}\)\(\Sigma\)\(_{g}\)\(^{+}\), v'=0,1,2) - rates and channels of energy transfer and quenching
Chemical Physics, 122 (3) :463-470
1988

216.

Wildt, Jürgen; Bednarek, G.; Fink, Ewald H.; Wayne, Richard P.
Laser excitation of O2(b1Σg+, v'=0,1,2) - rates and channels of energy transfer and quenching
Chemical Physics, 122 (3) :463-470
1988

215.

Heilmann, Margareta
Lp-saturation of some modified Bernstein operators
Journal of Approximation Theory, 54 (3) :260-273
1988
ISSN: 0021-9045

214.

Weinmüller, E.; Winkler, E.
Path-following Algorithm for Singular Boundary Value Problems
ZAMM, 68 :527--537
1988

213.

Becker, Karl Heinz; Brockmann, Klaus Josef; Wiesen, Peter
Spectroscopic identification of C(\(^{3}\)P) atoms in halogenomethane + H flame systems and measurements of C(\(^{3}\)P) reaction rate constants by two-photon laser-induced fluorescence
Journal of the Chemical Society, Faraday Transactions 2, 84 (5) :455-461
1988

212.

Becker, Karl Heinz; Brockmann, Klaus Josef; Wiesen, Peter
Spectroscopic identification of C(\(^{3}\)P) atoms in halogenomethane + H flame systems and measurements of C(\(^{3}\)P) reaction rate constants by two-photon laser-induced fluorescence
Journal of the Chemical Society, Faraday Transactions 2, 84 (5) :455-461
1988

211.

Becker, Karl Heinz; Brockmann, Klaus Josef; Wiesen, Peter
Spectroscopic identification of C(3P) atoms in halogenomethane + H flame systems and measurements of C(3P) reaction rate constants by two-photon laser-induced fluorescence
Journal of the Chemical Society, Faraday Transactions 2, 84 (5) :455-461
1988

210.

Fink, Ewald H.; Setzer, Klaus-Dieter; Kottsieper, U.; Ramsay, D. A.; Vervloet, M.
The a\(^{1}\)\(\Delta\)(a2)-X\(^{3}\)\(\Sigma\)\(^{-}\)(X\(_{2}\)1) electronic band system of selenium monoxide
Journal of Molecular Spectroscopy, 131 (1) :127-132
1988

209.

Fink, Ewald H.; Setzer, Klaus-Dieter; Kottsieper, U.; Ramsay, D. A.; Vervloet, M.
The a\(^{1}\)\(\Delta\)(a2)-X\(^{3}\)\(\Sigma\)\(^{-}\)(X\(_{2}\)1) electronic band system of selenium monoxide
Journal of Molecular Spectroscopy, 131 (1) :127-132
1988

208.

Fink, Ewald H.; Setzer, Klaus-Dieter; Kottsieper, U.; Ramsay, D. A.; Vervloet, M.
The a1Δ(a2)-X3Σ-(X21) electronic band system of selenium monoxide
Journal of Molecular Spectroscopy, 131 (1) :127-132
1988

207.

Jensen, Per; Bunker, Philip R.
The potential surface and stretching frequencies X\verb=~=\(^{3}\)B\(_{1}\) methylene (CH\(_{2}\)) determined from experiment using the Morse oscillator-rigid bender internal dynamics Hamiltonian
The Journal of Chemical Physics, 89 (3) :1327-1332
1988

206.

Jensen, Per; Bunker, Philip R.
The potential surface and stretching frequencies X\verb=~=\(^{3}\)B\(_{1}\) methylene (CH\(_{2}\)) determined from experiment using the Morse oscillator-rigid bender internal dynamics Hamiltonian
The Journal of Chemical Physics, 89 (3) :1327-1332
1988

205.

Jensen, Per; Bunker, Philip R.
The potential surface and stretching frequencies X~3B1 methylene (CH2) determined from experiment using the Morse oscillator-rigid bender internal dynamics Hamiltonian
The Journal of Chemical Physics, 89 (3) :1327-1332
1988
1987

204.

Spirko, Vladim{í}r; Cejchan, A.; Jensen, Per
A new Morse-oscillator based Hamiltonian for H\(_{3}\)\(^{+}\): Explicit expressions for some vibrational matrix elements
Journal of Molecular Spectroscopy, 124 (2) :430-436
1987

203.

Spirko, Vladim{í}r; Cejchan, A.; Jensen, Per
A new Morse-oscillator based Hamiltonian for H\(_{3}\)\(^{+}\): Explicit expressions for some vibrational matrix elements
Journal of Molecular Spectroscopy, 124 (2) :430-436
1987

202.

Spirko, Vladimír; Cejchan, A.; Jensen, Per
A new Morse-oscillator based Hamiltonian for H3+: Explicit expressions for some vibrational matrix elements
Journal of Molecular Spectroscopy, 124 (2) :430-436
1987

201.

McLean, A. D.; Bunker, Philip R.; Escribano, R. M.; Jensen, Per
An ab initio calculation of \(\nu\)\(_{1}\) and \(\nu\)\(_{3}\) for triplet methylene (X\verb=~=\(^{3}\)B\(_{1}\) CH\(_{2}\)) and the determination of the vibrationless singlet-triplet splitting Te (a\verb=~=\(^{1}\)A\(_{1}\))
The Journal of Chemical Physics, 87 (4) :2166-2169
1987