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Hier finden Sie wissenschaftliche Publikationen aus den FraunhoferInstituten. Calculation of ohmic losses in litz wires by coupling analytical and numerical methods
 Institute of Electrical and Electronics Engineers IEEE; Verband Deutscher Maschinen und Anlagenbau e.V. VDMA, Frankfurt/Main: 4th International Electric Drives Production Conference, EDPC 2014 : 30.09. – 01.10.2014, Nuremberg, Germany Piscataway, NJ: IEEE, 2014 ISBN: 9781479950089 ISBN: 9781479950096 ISBN: 9781479950102 S.385390 
 International Electric Drives Production Conference (EDPC) <4, 2014, Nuremberg> 

 Englisch 
 Konferenzbeitrag 
 Fraunhofer IISB () 
 litz wire; loss calculation; proximity effect; skin effect; electromagnetic simulation 
Abstract
Up to now, litz wires with many (several hundreds) strands are simplified in complex systems such as transformers or coils to make simulations feasible. However, frequency dependent losses of litz wires and solid conductors differ strongly. In this paper, a coupled process of numerical simulation and analytical methods is described which allows efficient simulation of full 3D structures including resolving litz wire substructure. To achieve this, 3D simulation with a simplified conductor calculates the magnetic field in the entire system. Based on these data, a new analytical method determines the losses in the litz wire along the conductor for the large number of 2D crosssections. The error of the analytical method is less than 5% at frequencies up to 1MHz and external magnetic fields u p to 2500kA/m. Because of the significant reduction of calculation time, windings and ferrite structures can be efficiently optimized.