Journal ArticleDOI
Effects of eddy currents in transformer windings
P.L. Dowell
- Vol. 113, Iss: 8, pp 1387-1394
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
In-Situ Measurement and Investigation of Winding Loss in High-Frequency Cored Transformers Under Large-Signal Condition
Navid Rasekh,Jun Wang,Xibo Yuan +2 more
TL;DR: In this paper , an in-situ measurement method was proposed to accurately characterize the winding loss in high-frequency (HF) transformers, which is challenging to quantify in power electronics applications.
Proceedings ArticleDOI
Design of Bi-directional CLLC Resonant Converter with Planar Transformer and Synchronous Rectification for Energy Storage Systems
TL;DR: In this article, a bidirectional CLLC resonant converter for low-voltage energy storage systems (48V) applications is presented, where the switching frequency is kept around 300-350 kHz to reduce the size of passives components, which facilitates the usage of planar transformers to enhance power density.
DissertationDOI
Interferometric switches for transparent networks : development and integration
TL;DR: The maturity of planar lithographic techniques that are widely used in microelectronics is leveraged to realize integrated versions of the fiber-based interferometric switches, including the selection of a suitable material system, design of the waveguide geometry, and creation and calibration of a fabrication process based on direct-write scanning electron-beam lithography.
Proceedings ArticleDOI
In-slot Direct Cooling Design and Optimization for Electric Machines
Yanyan Xie,Luke Chen,Xiaodan Wang,Julia Zhang,Franco Leonardi,Bob M. Sung,Alfredo R. Munoz,Michael W. Degner +7 more
TL;DR: In this paper, a thermal-network based numerical modeling approach combined with finite element (FE) EM simulations was used to evaluate the proposed in-slot cooling scheme and compares it with a drip-cooled machine product from multiple aspects, such as torque output, temperature, efficiency and pump power.
Journal ArticleDOI
An Accurate Analytical Method for Leakage Inductance Calculation of Shell-Type Transformers With Rectangular Windings
TL;DR: In this article, the leakage inductance of shell-type E-core transformers with rectangular windings is calculated using 2-dimensional analytical methods using the Mean Length of Turn (MLT) metric.
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.