Arbeitsgruppe Angewandte Mathematik / Numerische Analysis
Bergische Universität Wuppertal
Telefon: +49 202 439 5296
Fax: (Fax aktuell nicht erreichbar)
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.
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.
Coupled Heat-Electromagnetic Simulation of Inductive Charging Stations for Electric Vehicles
In Fontes et al, Editor, ECMI2012 proceedings
Herausgeber: Springer, Berlin
Extended Brauer Model for Ferromagnetic mmaterial: Analysis & ComputationSCEE 2012 Proceedings, :accepted
Quantification of Uncertainty in the Field Quality of Magnets Originating from Material MeasurementsIEEE Trans. on Magnetics, 49(5):2367-2370
Higher-Order Cosimulation of Field/Circuit Coupled ProblemsIEEE Trans. on Magnetics, :to appear
Higher Order Half-Explicit Time Integration of Eddy Current Problems Using domain substructuringIEEE Trans. on Magnetics, :to appear
Multiscale Modeling and Multirate Time-Integration of Field/Circuit Coupled Problems
Herausgeber: VDI Verlag, Düsseldorf
Zusammenfassung: This treatise is intended for mathematicians and computational engineers that work on modeling, coupling and simulation of electromagnetic problems. This includes lumped electric networks, magnetoquasistatic field and semiconductor devices. Their coupling yields a multiscale system of partial differential algebraic equations containing device models of any dimension interconnected by the electric network. It is solved in time domain by multirate techniques that efficiently exploit the structure. The central idea is the usage of lumped surrogate models that describe latent model parts sufficiently accurate (e.g. the field model by an inductance) even if other model parts (e.g. the circuit) exhibit highly dynamic behavior. We propose dynamic iteration and a bypassing technique using surrogate Schur complements. A mathematical convergence analysis is given and numerical examples are discussed. They show a clear reduction in the computational costs compared to single rate approaches.
A co-simulation framework for multirate time-integration of field/circuit coupled problemsIEEE Transactions on Magnetics, 46:3233 -- 3236
DAE-index and convergence analysis of lumped electric circuits refined by 3-D magnetoquasistatic conductor models
In Roos, Janne and Costa, L., Editor, Scientific Computing in Electrical Engineering. Mathematics in Industry aus 14 , Seite 341-- 348.
Herausgeber: Springer, Berlin
Modeling and discretization of circuit problems
In Schilders, W. H. A. and ter Maten, E. Jan W., Editor,
Seite 523 -- 659.
Herausgeber: Elsevier North Holland, Amsterdam