​Doctoral Thesis: Miniaturizing High Step-Down, High Output Current Power Converters


Event Speaker: 

Mike K. Ranjram

Event Location: 

via Zoom, see details below

Event Date/Time: 

Tuesday, May 4, 2021 - 2:00pm


Power conversion systems providing high voltage step-down capability at high output current are required in many common and emerging applications, such as data center servers, point-of-load conversion, electric vehicle charging, and USB power delivery. In these applications, converter miniaturization, reducing system volume while increasing efficiency, is a critical but especially challenging design goal. Transformers are ubiquitously employed in these systems and present a critical bottleneck towards miniaturization.
This thesis proposes a new paradigm for miniaturization in which magnetic and electronic systems are hybridized, viewed and designed as one coupled system, rather than their conventional treatment as separate elements. Two such systems are explored in detail: the Variable Inverter/Rectifier Transformer (VIRT) and its multi-phase counterpart, the Split-Phase Half-Turn VIRT (SPHTV). These are especially well-suited for high step-down, high output current conversion and are used to demonstrate highly miniaturized converters for portable charger and data center applications. Challenges associated with conventional means for handling high current, leveraging highly interleaved and high-layer-count planar windings, are elucidated and mitigation strategies are proposed. Finally, a general modeling framework for developing new coupled electronic and magnetic systems is presented, enabling this paradigm to be applied towards miniaturization efforts in other power conversion applications where passive components present a critical performance bottleneck. 
Thesis Committee:
​Prof. David J. Perreault (Thesis Supervisor)
Prof. Jeffrey H. Lang
Prof. Steven B. Leeb
Prof. Robert C. N. Pilawa-Podgurski (Berkeley)
To attend this defense, please contact the doctoral candidate at mranjram at mit dot edu