Developments for the high frequency power transformer design and implementation
No Thumbnail Available
Journal Title
Journal ISSN
Volume Title
Doctoral thesis (article-based)
Checking the digitized thesis and permission for publishing
Instructions for the author
Instructions for the author
Unless otherwise stated, all rights belong to the author. You may download, display and print this publication for Your own personal use. Commercial use is prohibited.
Author
Date
2003-06-13
Major/Subject
Mcode
Degree programme
Language
en
Pages
29, [62]
Series
Helsinki University of Technology, Applied Electronics Laboratory. B, Research reports, 13
Abstract
The thesis considers design and manufacturing of ferrite based high frequency power transformers. The primary aim of the work was to study core and winding losses and in particular thermal modeling of high frequency power transformers and to determine appropriate loss and temperature rise modeling methods for power converter applications. The secondary aim of the work was to study improved, mass manufacturable winding methods for toroidal, tube-type planar and disc-type planar high frequency power transformers. The analytical high frequency power transformer design equations for core and winding losses and transformer temperature rise were reviewed from literature, formulated for spreadsheet type calculations using excitation, material, geometry and winding implementation parameters and validated by in circuit temperature rise comparisons between calculated and measured values using regression analysis. The core and winding loss calculation methods in literature were found to provide appropriate accuracy for the practical design purposes. Thermal test block tests suggested a slight modification for analytical convective heat transfer equation from the literature. The results from in circuit temperature rise comparisons suggest that the transformer total losses can be predicted with the average standard error below 0.2 W with datasheet type information only. Further, if conductive thermal resistance from transformer via printed circuit board substrate to ambient is available the transformer operating temperature could be predicted with appropriate accuracy (5.6 °C) as well. The new manufacturing methods developed for toroidal, tube and disc-type transformer geometries were proved to be suitable for high frequency operation. With a common mode choke with static shield and windings deposited and etched directly on the toroidal NiZn core a transfer loss resonant frequency above 1.2 GHz was achieved. A multilayer foil winding with interleaved primary and secondary layers resulted resulted leakage inductance of 10 % of the value achieved using a wire-wound winding. The new developments for Z-folded inductive components resulted material cost savings, reduction of winding resistance and adjustability of leakage inductance and winding capacitances.Description
Keywords
high frequency power transformers, transformer design, transformer manufacturing, core loss modeling, winding loss, winding AC-resistance, thermal modeling, natural convection, planar transformer, toroidal winding, Z-folded winding
Other note
Parts
- Sippola M. and Sepponen R., DC/DC Converter Technology for distributed telecom and microprocessor power systems – a literature review. Submitted to IEEE Aerospace and Electronic Systems Magazine. Applied Electronics Laboratory Research Report (optionally).
- Sippola M. and Sepponen R., 2002. Accurate Prediction of High Frequency Power Transformer Losses and Temperature Rise. IEEE Transactions on Power Electronics 17, No. 5, pages 835-847.
- Sippola M., von Rauner T., Siren H. and Sepponen R., 2000. The Effect of Printed Circuit Board on Cooling and EMC of Switched Mode Power Supply. Proceedings of the IEEE 31st Annual Power Electronics Specialists Conference (PESC00). Galway, Ireland, 18-23 June 2000. Vol. 3, pages 1267-1272.
- Sippola M. and Siren H., 1998. New winding method for common mode choke. Proceedings of the 6th Biennal Conference on Electronics and Microsystems Technology (BEC'98). Tallinn, Estonia, 7-9 October 1998, pages 49-52.
- Sippola M. and Sepponen R., 2000. A manufacturing method for multilayer tube winding with interleaved primary and secondary windings. Proceedings of the 15th Annual IEEE Applied Power Electronics Conference and Exposition. New Orleans, Louisiana, USA, 6-10 February 2000. Vol. 2, pages 787-790.
- Sippola M. and Sepponen R., Reel-to-reel manufacturable, low cost, high performance Z-folded planar inductive components technology. Submitted to IEEE Transactions on Electronics Packaging Manufacturing, in review.
- Sippola M. and Sepponen R., Design for manufacturing considerations for Z-folded planar transformers. IEEE Transactions on Magnetics (submitted), Electronics Letters (submitted). Applied Electronics Laboratory Research Report (optionally).
