Optimal Design and Tradeoff Analysis of Planar Transformer in High-Power DC–DC Converters

Ziwei Ouyang, Ole Cornelius Thomsen, Michael A. E. Andersen

Research output: Contribution to journalJournal articleResearchpeer-review


The trend toward high power density, high operating frequency, and low profile in power converters has exposed a number of limitations in the use of conventional wire-wound magnetic component structures. A planar magnetic is a low-profile transformer or inductor utilizing planar windings, instead of the traditional windings made of Cu wires. In this paper, the most important factors for planar transformer (PT) design including winding loss, core loss, leakage inductance, and stray capacitance have individually been investigated. The tradeoffs among these factors have to be analyzed in order to achieve optimal parameters. Combined with an application, four typical winding arrangements have been compared to illustrate their advantages and disadvantages. An improved interleaving structure with optimal behaviors is proposed, which constructs the top layer paralleling with the bottom layer and then in series with the other turns of the primary, so that a lower magnetomotive force ratio $m$ can be obtained, as well as minimized ac resistance, leakage inductance, and even stray capacitance. A 1.2-kW full-bridge dc–dc converter prototype employing the improved PT structure has been constructed, over 96% efficiency is achieved, and a 2.7% improvement, compared with the noninterleaving structure, is obtained.
Original languageEnglish
JournalI E E E Transactions on Industrial Electronics
Issue number7
Pages (from-to)2800-2810
Publication statusPublished - 2012

Bibliographical note

Copyright 2010 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.


  • Leakage inductance
  • Core loss
  • Stray capacitance
  • Finite-element analysis (FEA)
  • Dc–dc converter
  • Interleaving
  • Planar transformer (PT)
  • Winding loss
  • Magnetomotive force (MMF)

Fingerprint Dive into the research topics of 'Optimal Design and Tradeoff Analysis of Planar Transformer in High-Power DC–DC Converters'. Together they form a unique fingerprint.

Cite this