Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor | Multi-disciplinary Studies | en_US |
| dc.contributor | Department of Applied Physics | en_US |
| dc.creator | Lai, Chi-wing | - |
| dc.identifier.uri | https://theses.lib.polyu.edu.hk/handle/200/1017 | - |
| dc.language | English | en_US |
| dc.publisher | Hong Kong Polytechnic University | - |
| dc.rights | All rights reserved | en_US |
| dc.title | Optimization of the efficiency of switched-mode power transformers | en_US |
| dcterms.abstract | Switched-mode power supplies are widely used nowadays. Nearly all power supplies are working in switched-mode because of its higher efficiency and smaller size. In this project, the efficiency optimization of the switched-mode power transformers (SMPT) is investigated, consideration taking into the temperature rise limit, the safety requirement and the size of the transformers. The dissertation starts with a study and delineation of the origin of the core losses (hysteresis loss and eddy-current loss) and the conductor losses (a.c. power loss and d.c. power loss). The core losses of some ETD (Efficient Transformer Design) type cores (5 different sizes and 2 different materials) are measured within a temperature-controlling chamber at different operating frequencies and magnetic flux densities. The actual core losses are then compared with the calculated values, in which the calculations are based on the power loss formula provided by the cores' manufacturer. The conductor losses of the enamelled copper wires with different wire gauge are measured at different operating frequencies under constant ambient temperature. The results obtained are then compared with the predicted values. Finally, the procedures for core selection and winding design are given. The core selection methods based on the cores' nomograms and the area product factor are introduced. The essential background information behind the design rules for high-frequency transformer winding is discussed first and then a practical winding design procedure is proposed. | en_US |
| dcterms.extent | iv, 100 leaves : ill. ; 30 cm | en_US |
| dcterms.isPartOf | PolyU Electronic Theses | en_US |
| dcterms.issued | 1999 | en_US |
| dcterms.educationalLevel | All Master | en_US |
| dcterms.educationalLevel | M.Sc. | en_US |
| dcterms.LCSH | Electric transformers | en_US |
| dcterms.LCSH | Switching circuits | en_US |
| dcterms.LCSH | Hong Kong Polytechnic University -- Dissertations | en_US |
| dcterms.accessRights | restricted access | en_US |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| b14835253.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 3.13 MB | Adobe PDF | View/Open |
Copyright Undertaking
As a bona fide Library user, I declare that:
- I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
- I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
- I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.
By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.
Please use this identifier to cite or link to this item:
https://theses.lib.polyu.edu.hk/handle/200/1017