{"id":{"repo_id":"york","oai_identifier":"oai:yorkspace.library.yorku.ca:10315/43377"},"canonical_url":"https://search.dev.ndltd.org/etd/york/oai:yorkspace.library.yorku.ca:10315/43377","repository":{"repo_id":"york","name":"York University","base_url":"https://yorkspace.library.yorku.ca/oai/request"},"display":{"title":"Stacked-Switched Electrolytic Capacitor-less AC/DC Power Converters","abstract":"The growing adoption of Electric Vehicles (EVs) has increased the demand for compact, efficient, and reliable On-Board Chargers (OBCs) capable of interfacing directly with the AC grid. Conventional single-phase AC/DC converters often depend on bulky electrolytic capacitors, diode bridges, and hard-switching circuits, leading to reduced reliability, increased losses, and limited power density. Additionally, the need for bidirectional energy flow—such as Vehicle-to-Grid (V2G) and Vehicle-to-Home (V2H)—requires grid-compliant converters with enhanced functionality and robust control strategies. This dissertation presents novel single-phase AC/DC converter topologies and control systems designed to eliminate electrolytic capacitors while enabling efficient bidirectional power transfer and robust grid-forming capabilities. The work is organized around three primary contributions. First, a unidirectional bridgeless AC/DC converter is proposed, utilizing a stacked-switch configuration to reduce voltage stress and operating in Discontinuous Conduction Mode (DCM) to achieve inherent power factor correction. Closed-loop control based on Variable Frequency Modulation (VFM) is used for voltage regulation, and a secondary-side duty modulation strategy minimizes low-frequency ripple, enabling the use of compact, long-life capacitors. Experimental validation on a 1.1kW prototype confirms high power factor (>0.99), low THD (<2.5%), and soft-switching operation. Second, a bidirectional converter is introduced, combining a half-bridge dual stacked-switch AC/DC stage and a CLLC resonant DC/DC stage. A dq-frame-based controller ensures low harmonic injection and effective grid synchronization in both power flow directions. Ripple reduction is again achieved through duty modulation, validated on a 1kW prototype. Finally, a robust grid-forming control scheme is developed using H_infinity synthesis with Linear Matrix Inequalities (LMIs), ensuring voltage stability under uncertainty and distortion. Experimental results confirm dynamic performance and low output distortion. Together, these contributions support next-generation EV charging systems with high reliability, bidirectional capability, and electrolytic capacitor-less design.","abstract_html":"The growing adoption of Electric Vehicles (EVs) has increased the demand for compact, efficient, and reliable On-Board Chargers (OBCs) capable of interfacing directly with the AC grid. Conventional single-phase AC/DC converters often depend on bulky electrolytic capacitors, diode bridges, and hard-switching circuits, leading to reduced reliability, increased losses, and limited power density. Additionally, the need for bidirectional energy flow—such as Vehicle-to-Grid (V2G) and Vehicle-to-Home (V2H)—requires grid-compliant converters with enhanced functionality and robust control strategies. This dissertation presents novel single-phase AC/DC converter topologies and control systems designed to eliminate electrolytic capacitors while enabling efficient bidirectional power transfer and robust grid-forming capabilities. The work is organized around three primary contributions. First, a unidirectional bridgeless AC/DC converter is proposed, utilizing a stacked-switch configuration to reduce voltage stress and operating in Discontinuous Conduction Mode (DCM) to achieve inherent power factor correction. Closed-loop control based on Variable Frequency Modulation (VFM) is used for voltage regulation, and a secondary-side duty modulation strategy minimizes low-frequency ripple, enabling the use of compact, long-life capacitors. Experimental validation on a 1.1kW prototype confirms high power factor (&gt;0.99), low THD (&lt;2.5%), and soft-switching operation. Second, a bidirectional converter is introduced, combining a half-bridge dual stacked-switch AC/DC stage and a CLLC resonant DC/DC stage. A dq-frame-based controller ensures low harmonic injection and effective grid synchronization in both power flow directions. Ripple reduction is again achieved through duty modulation, validated on a 1kW prototype. Finally, a robust grid-forming control scheme is developed using H_infinity synthesis with Linear Matrix Inequalities (LMIs), ensuring voltage stability under uncertainty and distortion. Experimental results confirm dynamic performance and low output distortion. Together, these contributions support next-generation EV charging systems with high reliability, bidirectional capability, and electrolytic capacitor-less design.","abstract_has_math":false,"creators":["Derakhshan, Siamak"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Lam, John Chi Wo"],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-11-11","date_published":"2025-11-11","updated_at":"2026-07-24T06:33:34Z","subjects":["Electrical engineering"],"languages":["en"],"rights":["Author owns copyright, except where explicitly noted. Please contact the author directly with licensing requests."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/10315/43377","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Lam, John Chi Wo"]},{"key":"dc:creator","label":"Author","values":["Derakhshan, Siamak"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2025-11-11T20:14:01Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2025-11-11T20:14:01Z"]},{"key":"dc:date.issued","label":"Date","values":["2025-11-11"]},{"key":"dc:type","label":"Dc Type","values":["Electronic Thesis or Dissertation"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Electrical engineering"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Author owns copyright, except where explicitly noted. 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This dissertation presents novel single-phase AC/DC converter topologies and control systems designed to eliminate electrolytic capacitors while enabling efficient bidirectional power transfer and robust grid-forming capabilities. The work is organized around three primary contributions. First, a unidirectional bridgeless AC/DC converter is proposed, utilizing a stacked-switch configuration to reduce voltage stress and operating in Discontinuous Conduction Mode (DCM) to achieve inherent power factor correction. Closed-loop control based on Variable Frequency Modulation (VFM) is used for voltage regulation, and a secondary-side duty modulation strategy minimizes low-frequency ripple, enabling the use of compact, long-life capacitors. Experimental validation on a 1.1kW prototype confirms high power factor (>0.99), low THD (<2.5%), and soft-switching operation. Second, a bidirectional converter is introduced, combining a half-bridge dual stacked-switch AC/DC stage and a CLLC resonant DC/DC stage. A dq-frame-based controller ensures low harmonic injection and effective grid synchronization in both power flow directions. Ripple reduction is again achieved through duty modulation, validated on a 1kW prototype. Finally, a robust grid-forming control scheme is developed using H_infinity synthesis with Linear Matrix Inequalities (LMIs), ensuring voltage stability under uncertainty and distortion. Experimental results confirm dynamic performance and low output distortion. Together, these contributions support next-generation EV charging systems with high reliability, bidirectional capability, and electrolytic capacitor-less design."]},{"key":"dc:title","label":"Title","values":["Stacked-Switched Electrolytic Capacitor-less AC/DC Power Converters"]}]}],"canonical_facts":{"dc:contributor.advisor":["Lam, John Chi Wo"],"dc:creator":["Derakhshan, Siamak"],"dc:date.accessioned":["2025-11-11T20:14:01Z"],"dc:date.available":["2025-11-11T20:14:01Z"],"dc:date.issued":["2025-11-11"],"dc:description.abstract":["The growing adoption of Electric Vehicles (EVs) has increased the demand for compact, efficient, and reliable On-Board Chargers (OBCs) capable of interfacing directly with the AC grid. Conventional single-phase AC/DC converters often depend on bulky electrolytic capacitors, diode bridges, and hard-switching circuits, leading to reduced reliability, increased losses, and limited power density. Additionally, the need for bidirectional energy flow—such as Vehicle-to-Grid (V2G) and Vehicle-to-Home (V2H)—requires grid-compliant converters with enhanced functionality and robust control strategies. This dissertation presents novel single-phase AC/DC converter topologies and control systems designed to eliminate electrolytic capacitors while enabling efficient bidirectional power transfer and robust grid-forming capabilities. The work is organized around three primary contributions. First, a unidirectional bridgeless AC/DC converter is proposed, utilizing a stacked-switch configuration to reduce voltage stress and operating in Discontinuous Conduction Mode (DCM) to achieve inherent power factor correction. Closed-loop control based on Variable Frequency Modulation (VFM) is used for voltage regulation, and a secondary-side duty modulation strategy minimizes low-frequency ripple, enabling the use of compact, long-life capacitors. Experimental validation on a 1.1kW prototype confirms high power factor (>0.99), low THD (<2.5%), and soft-switching operation. Second, a bidirectional converter is introduced, combining a half-bridge dual stacked-switch AC/DC stage and a CLLC resonant DC/DC stage. A dq-frame-based controller ensures low harmonic injection and effective grid synchronization in both power flow directions. Ripple reduction is again achieved through duty modulation, validated on a 1kW prototype. Finally, a robust grid-forming control scheme is developed using H_infinity synthesis with Linear Matrix Inequalities (LMIs), ensuring voltage stability under uncertainty and distortion. Experimental results confirm dynamic performance and low output distortion. Together, these contributions support next-generation EV charging systems with high reliability, bidirectional capability, and electrolytic capacitor-less design."],"dc:identifier.uri":["https://hdl.handle.net/10315/43377"],"dc:language":["en"],"dc:rights":["Author owns copyright, except where explicitly noted. Please contact the author directly with licensing requests."],"dc:subject":["Electrical engineering"],"dc:title":["Stacked-Switched Electrolytic Capacitor-less AC/DC Power Converters"],"dc:type":["Electronic Thesis or Dissertation"]},"updated_at":"2026-07-24T06:33:34Z"}