CREATOR @ SCEE 2024

Christian Bergfried, Leon Blumrich, Yvonne Späck-Leigsnering, Armin Galetzka, Herbert De Gersem. Calibration of a Squirrel-Cage Induction Machine Thermal Model. SCEE 2024. Darmstadt. March 4-8, 2024.

A two-dimensional finite element model of an induction machine is developed to study electrothermal stresses of the machine’s insulation system. Various three-dimensional thermal effects, such as the axial heat transfer along the shaft, are not considered in a standard two-dimensional model. In a previous paper, these effects have been included using a heuristic approach. Now, an inverse problem is defined and adopted to calibrate the model parameters of the squirrel cage induction machine.

Herbert Egger, Felix Engertsberger, Bogdan Radu. On the convergence of iterative solvers for nonlinear magnetostatics. SCEE 2024. Darmstadt. March 4-8, 2024.

We consider the iterative solution of systems arising in nonlinear magnetostatics. Using the equivalence to an underlying minimization problem, we can establish global linear convergence of a large class of methods, including the damped Newton-method, fixed-point iteration, and the Kacanov iteration, which can all be interpreted as generalized gradient descent methods. Armijo backtracking is considered for an adaptive choice of the stepsize. The general assumptions required for our analysis cover inhomogeneous, nonlinear, and anisotropic materials, as well as permanent magnets. The main results are proven on the continuous level, but they carry over almost verbatim to various approximation schemes, including finite elements and isogeometric analysis, leading to bounds on the iteration numbers, which are independent of the particular discretization. The theoretical results are illustrated by numerical tests for a typical benchmark problem.

Nepomuk Krenn, Peter Gangl. Multi-material topology optimization of an electric machine considering demagnetization. SCEE 2024. Darmstadt. March 4-8, 2024.

We consider the topology optimization problem of a 2d permanent mag net synchronous machine in magnetostatic operation with demagnetiza tion. This amounts to a PDE-constrained multi-material design optimiza tion problem with an additional pointwise state constraint. Using a generic framework we can incorporate this additional constraint and compute the corresponding topological derivative. We present and discuss optimization results obtained by a multi-material level set algorithm.