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Design and TID Testing of COTS-Based, Two-Phase, Point-of-Load Converters Using GaN HEMTs for Aerospace Applications

Helbig, Sabrina (2023) Design and TID Testing of COTS-Based, Two-Phase, Point-of-Load Converters Using GaN HEMTs for Aerospace Applications. Master's Thesis, University of Pittsburgh. (Unpublished)

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The use of commercial off-the-shelf (COTS) parts in space applications has elicited increased interest, especially in the pursuit of higher-performance satellite hardware for missions that can accept higher risk. This hardware includes DC-DC point-of-load (PoL) converters; this category of power electronics performs the critical function of adjusting the voltage and current levels provided by a mission's power distribution infrastructure in order to appropriately feed its loads, which are often computational in nature. The COTS-equivalent parts available for PoL converters enable significantly higher efficiencies, increased current output, reduced volume and mass, improved EMI characteristics, and lower costs. Additionally, the growing availability of COTS switching devices based in gallium nitride (GaN), which is a wide bandgap semiconductor, offers fast switching with reliable radiation performance in a small physical footprint, among other advantages. To effectively integrate potential COTS components into aerospace designs that feature high-power processors, FPGAs, and memories as loads, it is necessary to ascertain the total ionizing dose (TID) tolerance of the COTS control circuitry and power switches. As a result, multiple high-power-density, two-phase synchronous buck converters were developed utilizing various COTS control chips and GaN high electron mobility transistors (HEMTs). GaN devices were used due to their resistance to TID, with several devices having been tested up to 1Mrad. Additionally, multiphase buck converters are a favorite for generating high current power rails that are needed for computational loads like FPGAs. A variety of silicon-based COTS controllers and GaN HEMTs were selected as candidates for future mission applications based on current and voltage ratings.

A comparison between the designed PoL modules is presented with both simulation and hardware results. To see how the controllers perform in a radiation environment, the various modules were stressed up to 10krad through enhanced low dose rate sensitivity (ELDRS) testing and up to 100krad at a high dose rate. Converters were tested and measured against their baseline performance after each application of radiation. The converter modules’ electrical design and characteristics before, throughout, and after radiation testing, as well as comparisons between simulation and hardware performance and measured efficiency data, are presented.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Helbig, Sabrinasrh86@pitt.edusrh860000-0003-1391-770X
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Thesis AdvisorGrainger,
Committee ChairGrainger,
Committee MemberKim, Hong
Committee MemberLee,
Date: 13 June 2023
Date Type: Publication
Defense Date: 5 December 2022
Approval Date: 13 June 2023
Submission Date: 20 January 2023
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 58
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Electrical and Computer Engineering
Degree: MS - Master of Science
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: point-of-load converters, multiphase converters, aerospace power electronics, TID, COTS, GaN
Date Deposited: 13 Jun 2023 14:02
Last Modified: 13 Jun 2023 14:02


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