Proceedings ArticleDOI
Computer-aided design for high-frequency power transformers
P.M. Gradzki,M.M. Jovanovic,Fred C. Lee +2 more
- pp 336-343
TLDR
In this article, a multidimensional minimum search algorithm was used to design the smallest transformer and determine the optimum number of turns, winding space allocation, and size of the magnetic core.Abstract:
A computer-aided tool for design and analysis of high-frequency power transformers has been developed The program uses a multidimensional minimum-search algorithm to design the smallest transformer and determine the optimum number of turns, winding space allocation, and size of the magnetic core The design specifications include current and voltage waveforms, desired core shape and material, type of winding (Litz wire, solid wire, or foil), and primary and secondary winding arrangement The program also calculates the core loss and computes the winding loss distribution, taking into account proximity and skin effects An experimental transformer was designed for a 75 W offline zero-current quasi-resonant converter to verify the calculations >read more
Citations
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Proceedings ArticleDOI
Calculation of losses in ferro- and ferrimagnetic materials based on the modified Steinmetz equation
TL;DR: In this paper, the influence of nonsinusoidal flux-waveforms on the remagnetization losses in ferro- and ferrimagnetic materials of inductors, transformers and electrical machines used in power electronic applications is discussed.
Journal ArticleDOI
Winding resistance of litz-wire and multi-strand inductors
TL;DR: In this paper, an approximate model for multi-strand wire winding, including litz-wire winding, is presented, which takes into account the existence of proximity effect within the litzwire bundle between the strands and between the bundles, as well the skin effect.
Journal ArticleDOI
Analytical Optimization of Solid–Round-Wire Windings
TL;DR: New closed-form analytical equations are derived for the normalized solid-round-wire diameter to achieve minimum ac winding losses for sinusoidal current that enable inductor and transformer designers to minimize winding loss without utilizing finite-element method analysis.
Journal ArticleDOI
Accurate prediction of high-frequency power-transformer losses and temperature rise
Mika Sippola,Raimo Sepponen +1 more
TL;DR: In this paper, the high-frequency power-transformer design equations for winding and core losses and temperature rise were reviewed from literature and formulated for spreadsheet calculations using material (Steinmetz loss coefficients, ferrite resistivity, copper resistivity), geometry (core area, core length, winding area, winding length), winding (number of primary turns, copper fill factor, primary to secondary area ratio) and excitation (input voltage, switching frequency, duty cycle, current harmonic components) parameters.
Journal ArticleDOI
Case-based reasoning approach to concurrent design of low power transformers
C. K. Kwong,S. M. Tam +1 more
TL;DR: An artificial intelligence technique, case-based reasoning, is introduced to perform the concurrent product and process design of low power transformers from which a prototype concurrent design system, named CBS-TX, was developed.
References
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Journal ArticleDOI
Zero-voltage-switching multi-resonant technique-a novel approach to improve performance of high frequency quasi-resonant converters
W.A. Tabisz,Fred C. Lee +1 more
TL;DR: In this paper, a novel multiresonant switch concept is proposed to overcome the parasitic oscillations caused by the junction capacitance of the rectifying diode, which results in favorable switching conditions for all devices.
Proceedings ArticleDOI
Zero-voltage switching in high frequency power converters using pulse width modulation
TL;DR: In this article, a zero-voltage switching technique that utilizes a resonant transition during a short but finite switching interval is described. But, conduction losses are increased because ripple currents are increased and synchronous rectification is required.
Proceedings ArticleDOI
Zero-voltage switching technique in DC/DC converters
Kwang-Hwa Liu,Fred C. Lee +1 more
TL;DR: In this article, a novel resonant switch operating under the principle of zerovoltage switching is presented, which eliminates the switching loss and dv/dt noise due to discharging of MOSFET's junction capacitances and the reverse recovery of diodes, and enables the converters to operate at yet higher frequencies.
Journal ArticleDOI
A novel approach for minimizing high-frequency transformer copper losses
J. P. Vandelac,Phoivos D. Ziogas +1 more
TL;DR: In this article, a graphical and numerical method of calculating and minimizing losses in windings, that generalizes previous findings, has been introduced using electromagnetic theory and MMF diagrams in both space and time.
Proceedings ArticleDOI
Resonant Switches - A Unified Approach to Improve Performances of Switching Converters
Kwang-Hwa Liu,Fred C. Lee +1 more
TL;DR: In searching for a general "zero-current-Switching" technique for DC-DC converters, the concept of resonant switches is developed and application of the resonant switch concept to conventional converters leads to the discovery of a host of new converter circuits.