{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/104755"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/104755","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Improving data center power delivery efficiency and power density with differential power processing and multilevel power converters","abstract":"Existing data center power delivery architectures consist of many cascaded power conversion stages. The system-level power delivery efficiency decreases each time the requisite power is processed through the individual stages, and the total power converter footprint increases by each cascaded conversion stage. Innovative approaches are investigated in this dissertation for dc-dc step-down conversion and single-phase ac-dc conversion to improve power delivery efficiency and power density in data centers. This dissertation proposes a series-stacked architecture that provides inherently higher efficiency between a dc bus and dc loads through architectural changes, reporting above 99% power delivery efficiencies. The proposed series-stacked architecture increases power delivery efficiency by connecting the dc loads in series to allow the bulk of the requisite power to be delivered without being processed and by reducing overall power conversion using differential power processing. The series-stacked architecture exhibits voltage regulation and hot-swapping while delivering power to rapidly changing computational loads. This dissertation experimentally demonstrates series-stacked power delivery using real-life computational loads in a custom designed four-server rack. In order to provide a complete grid-to-12 V power delivery for data center applications, this dissertation also proposes a buck-type power factor correction converter that yields high power density between a single-phase grid and the dc bus, achieving 79 W/in3 power density. The proposed buck-type power factor correction converter improves power density by eliminating the high-voltage step-down dc-dc conversion stage, which is typically cascaded to boost-type power factor correction converters in conventional data center power delivery architectures, and by leveraging recent developments in flying capacitor multilevel converters using wide-bandgap transistors. The buck-type flying capacitor multilevel power factor correction converter presents a unique operation condition where the flying capacitor voltages are required to follow the input voltage at 50/60 Hz. This dissertation experimentally explores the applicability of such an operation by using a digitally controlled six-level flying capacitor multilevel converter prototype.","abstract_html":"Existing data center power delivery architectures consist of many cascaded power conversion stages. The system-level power delivery efficiency decreases each time the requisite power is processed through the individual stages, and the total power converter footprint increases by each cascaded conversion stage. Innovative approaches are investigated in this dissertation for dc-dc step-down conversion and single-phase ac-dc conversion to improve power delivery efficiency and power density in data centers. This dissertation proposes a series-stacked architecture that provides inherently higher efficiency between a dc bus and dc loads through architectural changes, reporting above 99% power delivery efficiencies. The proposed series-stacked architecture increases power delivery efficiency by connecting the dc loads in series to allow the bulk of the requisite power to be delivered without being processed and by reducing overall power conversion using differential power processing. The series-stacked architecture exhibits voltage regulation and hot-swapping while delivering power to rapidly changing computational loads. This dissertation experimentally demonstrates series-stacked power delivery using real-life computational loads in a custom designed four-server rack. In order to provide a complete grid-to-12 V power delivery for data center applications, this dissertation also proposes a buck-type power factor correction converter that yields high power density between a single-phase grid and the dc bus, achieving 79 W/in3 power density. The proposed buck-type power factor correction converter improves power density by eliminating the high-voltage step-down dc-dc conversion stage, which is typically cascaded to boost-type power factor correction converters in conventional data center power delivery architectures, and by leveraging recent developments in flying capacitor multilevel converters using wide-bandgap transistors. The buck-type flying capacitor multilevel power factor correction converter presents a unique operation condition where the flying capacitor voltages are required to follow the input voltage at 50/60 Hz. This dissertation experimentally explores the applicability of such an operation by using a digitally controlled six-level flying capacitor multilevel converter prototype.","abstract_has_math":false,"creators":["Candan, Enver"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Electrical & Computer Engr","degree_department":null,"school":null,"contributors":["Pilawa-Podgurski, Robert C.N.","Krein, Philip T.","Domínguez-García, Alejandro","Banerjee, Arijit","Shenoy, Pradeep S."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2019,"date_issued":"2019-08-23T19:51:31Z","date_published":"2019-08-23T19:51:31Z","updated_at":"2026-07-22T22:24:42Z","subjects":["Data center power delivery","series-stacked power delivery, differential power processing","flying capacitor multilevel converters","single-phase ac to dc conversion","power factor correction"],"languages":["en"],"rights":["Copyright 2019 Enver Candan"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/104755","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Pilawa-Podgurski, Robert C.N.","Krein, Philip T.","Domínguez-García, Alejandro","Banerjee, Arijit","Shenoy, Pradeep S."]},{"key":"dc:creator","label":"Author","values":["Candan, Enver"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2019-08-23T19:51:31Z","2019-03-08","2019-05"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical & Computer Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Data center power delivery","series-stacked power delivery, differential power processing","flying capacitor multilevel converters","single-phase ac to dc conversion","power factor correction"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2019 Enver Candan"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/104755"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Existing data center power delivery architectures consist of many cascaded power conversion stages. The system-level power delivery efficiency decreases each time the requisite power is processed through the individual stages, and the total power converter footprint increases by each cascaded conversion stage. Innovative approaches are investigated in this dissertation for dc-dc step-down conversion and single-phase ac-dc conversion to improve power delivery efficiency and power density in data centers. This dissertation proposes a series-stacked architecture that provides inherently higher efficiency between a dc bus and dc loads through architectural changes, reporting above 99% power delivery efficiencies. The proposed series-stacked architecture increases power delivery efficiency by connecting the dc loads in series to allow the bulk of the requisite power to be delivered without being processed and by reducing overall power conversion using differential power processing. The series-stacked architecture exhibits voltage regulation and hot-swapping while delivering power to rapidly changing computational loads. This dissertation experimentally demonstrates series-stacked power delivery using real-life computational loads in a custom designed four-server rack. In order to provide a complete grid-to-12 V power delivery for data center applications, this dissertation also proposes a buck-type power factor correction converter that yields high power density between a single-phase grid and the dc bus, achieving 79 W/in3 power density. The proposed buck-type power factor correction converter improves power density by eliminating the high-voltage step-down dc-dc conversion stage, which is typically cascaded to boost-type power factor correction converters in conventional data center power delivery architectures, and by leveraging recent developments in flying capacitor multilevel converters using wide-bandgap transistors. The buck-type flying capacitor multilevel power factor correction converter presents a unique operation condition where the flying capacitor voltages are required to follow the input voltage at 50/60 Hz. This dissertation experimentally explores the applicability of such an operation by using a digitally controlled six-level flying capacitor multilevel converter prototype.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2019-08-22 without embargo terms","The student, Enver Candan, accepted the attached license on 2019-03-07 at 21:23.","The student, Enver Candan, submitted this Dissertation for approval on 2019-03-07 at 21:33.","This Dissertation was approved for publication on 2019-03-08 at 10:11.","DSpace SAF Submission Ingestion Package generated from Vireo submission #13415 on 2019-08-22 at 14:40:33","Made available in DSpace on 2019-08-23T19:51:31Z (GMT). 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The series-stacked architecture exhibits voltage regulation and hot-swapping while delivering power to rapidly changing computational loads. This dissertation experimentally demonstrates series-stacked power delivery using real-life computational loads in a custom designed four-server rack. In order to provide a complete grid-to-12 V power delivery for data center applications, this dissertation also proposes a buck-type power factor correction converter that yields high power density between a single-phase grid and the dc bus, achieving 79 W/in3 power density. The proposed buck-type power factor correction converter improves power density by eliminating the high-voltage step-down dc-dc conversion stage, which is typically cascaded to boost-type power factor correction converters in conventional data center power delivery architectures, and by leveraging recent developments in flying capacitor multilevel converters using wide-bandgap transistors. The buck-type flying capacitor multilevel power factor correction converter presents a unique operation condition where the flying capacitor voltages are required to follow the input voltage at 50/60 Hz. This dissertation experimentally explores the applicability of such an operation by using a digitally controlled six-level flying capacitor multilevel converter prototype.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2019-08-22 without embargo terms","The student, Enver Candan, accepted the attached license on 2019-03-07 at 21:23.","The student, Enver Candan, submitted this Dissertation for approval on 2019-03-07 at 21:33.","This Dissertation was approved for publication on 2019-03-08 at 10:11.","DSpace SAF Submission Ingestion Package generated from Vireo submission #13415 on 2019-08-22 at 14:40:33","Made available in DSpace on 2019-08-23T19:51:31Z (GMT). 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