TY  - JOUR
AU  - Christmann, Jan-Magnus
AU  - D'Angelo, Laura Anna Maria
AU  - De Gersem, Herbert
AU  - Pfeiffer, Sven
AU  - Mirza, Sajjad Hussain
AU  - Thede, Matthias
AU  - Aloev, Alexander
AU  - Schlarb, Holger
TI  - Homogenized harmonic balance finite element method for nonlinear eddy current simulations of fast corrector magnets
JO  - Physical review accelerators and beams
VL  - 28
IS  - 10
SN  - 2469-9888
CY  - College Park, MD
PB  - American Physical Society
M1  - PUBDB-2025-04135
M1  - arXiv:2503.19657
M1  - arXiv:2503.19657
SP  - 104601
PY  - 2025
N1  - 18 pages, 27 figures, to be published in Physical Review Accelerators and Beams
AB  - This paper develops a homogenized harmonic balance finite element method (HomHBFEM) to predict the dynamic behavior of magnets with fast excitation cycles, including eddy current and skin effects. A homogenization technique for laminated yokes avoids resolving the individual laminates and the skin depth in the finite element (FE) mesh. Instead, the yoke is represented by a bulk surrogate material with frequency-dependent parameters. The ferromagnetic saturation of the yoke at higher excitation currents is tackled by a harmonic balance method, which accounts for a coupled set of frequency components. Thereby, a computationally expensive time stepping of the eddy-current field problem and a convolution of the homogenized yoke model are avoided. The HomHBFEM enables, for the first time, nonlinear simulations of fast corrector magnets, which are embedded in a fast orbit feedback system to counteract orbit disturbances over a broad frequency spectrum, and thus guarantee stable light-source operation. The results show the impact of the nonlinearity on the phase lag and the field attenuation, as well as the eddy current losses at frequencies up to several tens of kilohertz. The numerical validation for a C-dipole magnet example shows that the HomHBFEM achieves a sufficient accuracy at an affordable computational effort, with simulation times of a few hours. In comparison, standard 3D transient FE simulations need to resolve the lamination thickness and the skin depth in space and the largest relevant frequency in time, which leads to a 2 to 3 orders of magnitude larger mesh and prohibitive computational effort, with simulation times of a few weeks on a contemporary computer server.
LB  - PUB:(DE-HGF)16
DO  - DOI:10.1103/9mnn-w7lj
UR  - https://bib-pubdb1.desy.de/record/638668
ER  -