{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/132604"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/132604","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"A flying capacitor multilevel dual-active bridge converter for interfacing high voltage in more-electric aircraft","abstract":"More-electric aircraft (MEA) replace traditional mechanical and hydraulic subsystems with electrically powered equivalents, improving system-level power density, reliability, and maintainability. As MEA architectures approach the megawatt scale, both power generation and distribution voltage levels must increase, placing new demands on the power converters interfacing high-voltage buses with low-voltage buses and storage. While the dual-active bridge (DAB) converter has traditionally served this role, its reliance on single high-voltage devices constrains achievable switching frequency, resulting in bulky magnetics. The addition of a flying-capacitor multilevel (FCML) converter provides a high-frequency alternative that enables use of medium-voltage GaN technology, reduced magnetics volume, and improved theoretical efficiency across its operating range. The 6-level FCML-DAB converter is explored in this work, with a 700:28 V prototype achieving a peak efficiency of 93.75%.","abstract_html":"More-electric aircraft (MEA) replace traditional mechanical and hydraulic subsystems with electrically powered equivalents, improving system-level power density, reliability, and maintainability. As MEA architectures approach the megawatt scale, both power generation and distribution voltage levels must increase, placing new demands on the power converters interfacing high-voltage buses with low-voltage buses and storage. While the dual-active bridge (DAB) converter has traditionally served this role, its reliance on single high-voltage devices constrains achievable switching frequency, resulting in bulky magnetics. The addition of a flying-capacitor multilevel (FCML) converter provides a high-frequency alternative that enables use of medium-voltage GaN technology, reduced magnetics volume, and improved theoretical efficiency across its operating range. The 6-level FCML-DAB converter is explored in this work, with a 700:28 V prototype achieving a peak efficiency of 93.75%.","abstract_has_math":false,"creators":["Freeman, Andrew J."],"institution":"University of Illinois Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Electrical & Computer Engr","degree_department":null,"school":null,"contributors":["Stillwell, Andrew R"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-12","date_published":"2025-12","updated_at":"2026-07-22T22:25:07Z","subjects":["more-electric aircraft","power conversion","power electronics","flying capacitor multilevel","FCML","dual-active bridge","DAB"],"languages":["en"],"rights":["Copyright 2025 Andrew Freeman"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/132604","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Stillwell, Andrew R"]},{"key":"dc:creator","label":"Author","values":["Freeman, Andrew J."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2025-12","2025-12-12"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical & Computer Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["more-electric aircraft","power conversion","power electronics","flying capacitor multilevel","FCML","dual-active bridge","DAB"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2025 Andrew Freeman"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/132604"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["More-electric aircraft (MEA) replace traditional mechanical and hydraulic subsystems with electrically powered equivalents, improving system-level power density, reliability, and maintainability. As MEA architectures approach the megawatt scale, both power generation and distribution voltage levels must increase, placing new demands on the power converters interfacing high-voltage buses with low-voltage buses and storage. While the dual-active bridge (DAB) converter has traditionally served this role, its reliance on single high-voltage devices constrains achievable switching frequency, resulting in bulky magnetics. The addition of a flying-capacitor multilevel (FCML) converter provides a high-frequency alternative that enables use of medium-voltage GaN technology, reduced magnetics volume, and improved theoretical efficiency across its operating range. The 6-level FCML-DAB converter is explored in this work, with a 700:28 V prototype achieving a peak efficiency of 93.75%.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2026-02-19 without embargo terms","The student, Andrew Freeman, accepted the attached license on 2025-12-11 at 22:24.","The student, Andrew Freeman, submitted this Thesis for approval on 2025-12-11 at 22:55.","This Thesis was approved for publication on 2025-12-12 at 13:10.","DSpace SAF Submission Ingestion Package generated from Vireo submission #23143 on 2026-02-19 at 18:30:23"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["A flying capacitor multilevel dual-active bridge converter for interfacing high voltage in more-electric aircraft"]}]}],"canonical_facts":{"dc:contributor":["Stillwell, Andrew R"],"dc:creator":["Freeman, Andrew J."],"dc:date":["2025-12","2025-12-12"],"dc:description":["More-electric aircraft (MEA) replace traditional mechanical and hydraulic subsystems with electrically powered equivalents, improving system-level power density, reliability, and maintainability. As MEA architectures approach the megawatt scale, both power generation and distribution voltage levels must increase, placing new demands on the power converters interfacing high-voltage buses with low-voltage buses and storage. While the dual-active bridge (DAB) converter has traditionally served this role, its reliance on single high-voltage devices constrains achievable switching frequency, resulting in bulky magnetics. The addition of a flying-capacitor multilevel (FCML) converter provides a high-frequency alternative that enables use of medium-voltage GaN technology, reduced magnetics volume, and improved theoretical efficiency across its operating range. The 6-level FCML-DAB converter is explored in this work, with a 700:28 V prototype achieving a peak efficiency of 93.75%.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2026-02-19 without embargo terms","The student, Andrew Freeman, accepted the attached license on 2025-12-11 at 22:24.","The student, Andrew Freeman, submitted this Thesis for approval on 2025-12-11 at 22:55.","This Thesis was approved for publication on 2025-12-12 at 13:10.","DSpace SAF Submission Ingestion Package generated from Vireo submission #23143 on 2026-02-19 at 18:30:23"],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/132604"],"dc:language":["en"],"dc:rights":["Copyright 2025 Andrew Freeman"],"dc:subject":["more-electric aircraft","power conversion","power electronics","flying capacitor multilevel","FCML","dual-active bridge","DAB"],"dc:title":["A flying capacitor multilevel dual-active bridge converter for interfacing high voltage in more-electric aircraft"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Electrical & Computer Engr"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:07Z"}