| Improved Characterization of the Magnetic Properties of Hexagonally Packed Wires | ||||||
| Author(s) | H. Rossmanith; M. Albach; J. Fischer; A. Stadler | |||||
| Abstract | When designing passive magnetic components, calculations of the magnetic field distribution inside the winding window become necessary. Numerical calculations, but also other methods like the modal decomposition of the boundary value problem encounter difficulties, when the influence of a great number of wires (e.g. litz wire strands) has to be taken into account. To avoid discretization of a great number of tiny strands, a global property like an equivalent permeability may be used to characterize the macroscopic magnetic behavior (Fig. 1). If the magnetic field is characterized by complex amplitudes, this permeability also has a complex value. Its imaginary part describes the proximity losses in the winding.
A possibility to derive this permeability from the properties of a single strand is presented in [1], however, as already
stated there, this formula is not equally suited for all frequencies, permeabilities and various ratios of strand diameter to the total litz diameter. Especially for higher frequencies, as stated in [2], most approximation formulas deviate considerably from simulation data. In this paper, an improved complex permeability model for litz wire windings is derived heuristically from a comparison between simulation results and the standard analytical model. It is valid for all strand diameters, strand distances and frequencies, and may be used for accurate numerical calculations of magnetic fields and losses in magnetic components. |
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| Type | Members Only | |||||
| Date | Last modified 2013-03-29 by System | |||||
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