The increasing power demand in data centers drives the need for high step down dc/dc converters that also offer improved efficiency and power density performance. High conversion ratio dc/dc converters are fundamentally more challenging to design due to the high indirect power requirement. Therefore, “dc transformer” (DCX) converters such as the isolated dual-active-bridge (DAB) and the non-isolated switched-capacitor (SC) converters have been of wide interests.
The fundamental question addressed in this thesis is how to combine the benefits of DA Band SC converters and reproduce DAB converter operating characteristics in non-isolated (transformerless) converters. This work offers an affirmative answer to this question by introducing a new class of hybrid dc-dc converters named Transformerless Stacked Active Bridge (TSAB) converters as an approach to hybridization of conventional SC converters. Generalized analysis, systematic synthesis, design optimization and comparison of TSAB converters are presented.
Features of TSAB converters include soft charging and discharging of capacitors, zero-voltage switching, low peak and root-mean-square (RMS) current stresses, low energy storage requirement of magnetic components, and regulation capabilities using simple phase-shift control. Systematic synthesis allows TSAB converters to be obtained from many well-known SC parent topologies, including Dickson, ladder, stacked-ladder, doubler, and Fibonacci. Experimental results are summarized for 48-to-12 V doubler, 48-to-12 V Dickson, and 36-to-12 V ladder TSAB prototypes. It is shown how the TSAB prototypes use small ac inductors (10’s to 100’s of nH) while operatingat relatively low switching frequencies (150-200 kHz) and have measured efficiency above 98% overwide load range. Additionally, it is shown how TSAB converters can be merged with the follow-upregulation stage for point-of-load (PoL) applications. 94% peak efficiency is demonstrated in a 48 Vto 0.8-1.8 V, 100 A prototype.
|Commitee:||Erickson , Robert W., Le, Hanh-phuc, Poveda, Jorge I., Seo, Gabsu|
|School:||University of Colorado at Boulder|
|School Location:||United States -- Colorado|
|Source:||DAI-A 82/6(E), Dissertation Abstracts International|
|Subjects:||Electrical engineering, Design, Management, Industrial engineering, Electromagnetics, Energy|
|Keywords:||Data Center (DC), DC transformer, DC-DC converter synthesis, DC-DC converter topologies, Hybrid converters, Power density performance, Dual-active-bridge (DAB), Switched-capacitor (SC) converters, Zero-voltage switching|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be