2026-09-19T03:48:02Zhttps://dspace.mit.edu/server/oai/requestoai:dspace.mit.edu:1721.1/1393482022-01-15T03:04:19Zcom_1721.1_7582com_1721.1_7581col_1721.1_131022
Perreault, David J.
Ranjram, Mike Kavian
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
2022-01-14T15:05:38Z
2022-01-14T15:05:38Z
2021-06
2021-06-23T19:40:10.123Z
https://hdl.handle.net/1721.1/139348
https://orcid.org/0000-0002-6513-1488
Power conversion systems providing high voltage step-down capability at high output current are required in many applications, such as data center servers, electric vehicle charging, and USB power delivery. Converter miniaturization is a critical but especially challenging design goal, and transformers present a key bottleneck in this effort. To address this challenge, a new paradigm for magnetic component design is proposed in which magnetic and electronic elements are viewed as a single ``coupled electronic and magnetic system'' (CEMS).
The first proposed CEMS is the Variable Inverter/Rectifier Transformer (VIRT), which enables a transformer with fractional and reconfigurable effective turns ratios (e.g. 12:0.5, 12:2/3, 12:1, and 12:2). Its wide gain variation and high step-down capability are utilized in a 120-380V input, 5-20V, 5A/36W output dc/dc converter having a peak efficiency of 96% and greater than 93% efficiency across the wide range. The VIRT is also employed in a two-stage universal ac input, 5/9/12V, 5A/50W output portable charger having a component power density of 55W/in3 and a peak end-to-end efficiency of 95.7%.
Challenges associated with leveraging highly interleaved high-layer-count planar windings - another means for handling high current - are elucidated and mitigation strategies are proposed. A novel winding termination strategy is demonstrated to reduce ac resistance by more than 40% in a highly interleaved design.
A CEMS that is especially well suited for processing high output current is derived by combining the VIRT with popular multi-phase concepts. The resulting split-phase half-turn VIRT is employed in a 380V input, 12V/1kW output data center supply having a peak efficiency of 97.7% and a full-load efficiency of 97.1% with a transformer volume up to 36% smaller than best-in-class alternatives. Finally, a generalized modeling framework for developing new CEMS implementations is presented.
Ph.D.
Massachusetts Institute of Technology
In Copyright - Educational Use Permitted
Copyright MIT
http://rightsstatements.org/page/InC-EDU/1.0/
Miniaturizing High Step-Down, High Output Current Power Converters
Thesis
application/pdf
Doctoral
Doctor of Philosophy
Publication
unknown
unknown
<Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="e7556626-a575-449e-ac6b-6730ead6512d">
<Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type>
<Title>Miniaturizing High Step-Down, High Output Current Power Converters</Title>
<PublishedIn>
<Publication>
</Publication>
</PublishedIn>
<PublicationDate>2021-06</PublicationDate>
<Authors>
<Author>
<DisplayName>Ranjram, Mike Kavian</DisplayName>
<Affiliation>
<OrgUnit>
</OrgUnit>
</Affiliation>
</Author>
</Authors>
<Editors>
</Editors>
<Publishers>
<Publisher>
<DisplayName>Massachusetts Institute of Technology</DisplayName>
<OrgUnit />
</Publisher>
</Publishers>
<License>http://rightsstatements.org/page/InC-EDU/1.0/</License>
<Abstract>Power conversion systems providing high voltage step-down capability at high output current are required in many applications, such as data center servers, electric vehicle charging, and USB power delivery. Converter miniaturization is a critical but especially challenging design goal, and transformers present a key bottleneck in this effort. To address this challenge, a new paradigm for magnetic component design is proposed in which magnetic and electronic elements are viewed as a single ``coupled electronic and magnetic system'' (CEMS).
The first proposed CEMS is the Variable Inverter/Rectifier Transformer (VIRT), which enables a transformer with fractional and reconfigurable effective turns ratios (e.g. 12:0.5, 12:2/3, 12:1, and 12:2). Its wide gain variation and high step-down capability are utilized in a 120-380V input, 5-20V, 5A/36W output dc/dc converter having a peak efficiency of 96% and greater than 93% efficiency across the wide range. The VIRT is also employed in a two-stage universal ac input, 5/9/12V, 5A/50W output portable charger having a component power density of 55W/in3 and a peak end-to-end efficiency of 95.7%.
Challenges associated with leveraging highly interleaved high-layer-count planar windings - another means for handling high current - are elucidated and mitigation strategies are proposed. A novel winding termination strategy is demonstrated to reduce ac resistance by more than 40% in a highly interleaved design.
A CEMS that is especially well suited for processing high output current is derived by combining the VIRT with popular multi-phase concepts. The resulting split-phase half-turn VIRT is employed in a 380V input, 12V/1kW output data center supply having a peak efficiency of 97.7% and a full-load efficiency of 97.1% with a transformer volume up to 36% smaller than best-in-class alternatives. Finally, a generalized modeling framework for developing new CEMS implementations is presented.</Abstract>
<Access xmlns="http://purl.org/coar/access_right"
>
</Access>
</Publication>