Journal ArticleDOI
Effects of eddy currents in transformer windings
P.L. Dowell
- Vol. 113, Iss: 8, pp 1387-1394
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TLDR
In this article, the effect of eddy currents on transformer windings is considered and a method is derived for calculating the variation of winding resistance and leakage inductance with frequency for transformers with single-layer, multilayer and sectionalised windings.Abstract:
The effects of eddy currents in transformer windings are considered, and a method is derived for calculating the variation of winding resistance and leakage inductance with frequency for transformers with single-layer, multilayer and sectionalised windings. The method consists in dividing the winding into portions, calculating the d.c. resistances and d.c. leakage inductances of each of these portions, and then multiplying the d.c. values by appropriate factors to obtain the corresponding a.c. values. These a.c. values are then referred to, say, the primary winding and summed to give the total winding resistance and leakage inductance of the transformer. Formulas are derived and quoted for calculating the d.c. resistances and leakage inductances of the winding portions. Theoretical expressions are derived for the variation with frequency etc. of the factors by which the d.c. values must be multiplied to obtain the corresponding a.c. values. These expressions are presented in the form of graphs, permitting the factors to be read as required.read more
Citations
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Journal ArticleDOI
Sensitivity Analysis of Medium-Frequency Transformer Designs for Solid-State Transformers
Marko Mogorovic,Drazen Dujic +1 more
TL;DR: The impact of modularity and choice of operating frequency directly related to selected semiconductors, reveal interesting trends that can aid overall solid-state transformer design optimization.
Journal ArticleDOI
AC Power Losses Model for Planar Windings With Rectangular Cross-Sectional Conductors
TL;DR: In this paper, a method to calculate the ac losses, including skin effect and proximity losses, in planar windings with rectangular cross-sectional conductors is proposed, where proper ac losses expressions similar to the formulas available for round crosssectional wires, to be used for the calculation of ac losses and the optimization of planar magnetic windings implemented in the printed circuit board.
Journal ArticleDOI
A Systematic Approach to Modeling Impedances and Current Distribution in Planar Magnetics
Minjie Chen,Mohammad Araghchini,Khurram K. Afridi,Jeffrey H. Lang,Charles R. Sullivan,David J. Perreault +5 more
TL;DR: In this paper, the modular layer model (MLM) is proposed to model planar magnetics based on a lumped circuit model, which captures skin and proximity effects and enables accurate predictions of impedances, losses, stored reactive energy, and current sharing among windings.
Journal ArticleDOI
AC Resistance Factor of Litz-Wire Windings Used in Low-Voltage High-Power Generators
TL;DR: It is found that the measured litz wire with originally noninsulated strands can be used in large electrical machines up to about 120 Hz if about 50% increase in ac resistance compared to the dc resistance is allowed.
Proceedings ArticleDOI
Optimization of shapes for round-wire high-frequency gapped-inductor windings
Jiankun Hu,Charles R. Sullivan +1 more
TL;DR: In this article, a numerical method is used to determine the winding shape that minimizes total winding losses in a gapped inductor with round-wire windings, which accounts for proximity effect loss that results from the two-dimensional field in the winding area, and for the effect of the winding on that field.
References
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Journal ArticleDOI
Effective resistance to alternating currents of multilayer windings
Edward Bennett,Sidney C. Larson +1 more
TL;DR: In this article, a multilayer winding carrying an alternating current, such as the windings illustrated in figures 1, 2, and 3, each layer of copper lies in the alternating magnetic field set up by the current in all the other layers.
Journal ArticleDOI
Eddy Currents in Large Slot-Wound Conductors
TL;DR: In this article, the authors discuss the more important causes of eddy currents in heavy conductors carrying alternating currents and surrounded on three sides by iron, and propose a method to identify the most important causes.
Journal ArticleDOI
Effective Resistance to Alternating Currents of Multilayer Windings
Journal ArticleDOI
Eddy-Current Losses in Cylindrical Conductors, with Special Applications to the Alternating Current Resistances of Short Coils
TL;DR: In this article, it is shown that a considerable proportion of the effective resistance of inductive coils when used at radio frequencies is caused by the eddy-currents set up in the wires of the coils by the alternating magnetic field in which they are situated, and that in extreme cases the alternating current resistance may amount to more than one hundred times the direct current resistance.
Journal ArticleDOI
Heat Losses in the Conductors of Alternating-Current Machines
TL;DR: In this article, the authors show how hyperbolic functions of complex angles may be applied to the solution of the problem of heat losses in rectangular conductors that are embedded in open slots.