{"schemaVersion":1,"slug":"doubly-fed-induction-generator","name":"Doubly-fed induction generator","kind":"symbol","abbreviation":"DFIG","aliases":["DFIG","Type 3 wind turbine generator","doubly-fed asynchronous generator"],"category":"microgrid-systems","drawingTypes":["SLD","Schematic"],"referenceFamilies":["IEC","IEEE / ANSI"],"summary":"A wound-rotor induction generator with the stator on the network and the rotor fed through a back-to-back converter sized for slip power.","description":["A doubly-fed induction generator has its stator connected directly to the turbine transformer while the rotor windings, reached through slip rings, connect to a back-to-back AC/DC/AC converter. The converter injects rotor currents at slip frequency, allowing variable speed of roughly plus or minus thirty per cent around synchronous speed and independent control of active and reactive power.","On a single-line diagram the generator circle shows two connections: the stator branch to the main breaker and the rotor branch to a pair of converter blocks joined by a DC link. A crowbar or DC chopper is often shown on the rotor converter for fault protection, and a line filter or reactor sits on the grid-side converter.","Because the converter only carries slip power, typically a quarter to a third of the turbine rating, the symbol does not imply full decoupling from the network. Short-circuit contribution, crowbar operation and ride-through capability depend on control settings that the diagram does not show."],"readingNotes":["Follow both the stator and rotor paths; they usually join again at the turbine transformer low-voltage side.","Identify the crowbar or chopper, since it changes fault behaviour."],"drawingChecklist":["State stator rating and rotor converter rating separately.","Show crowbar, chopper and line filter if fitted.","Reference grid-code ride-through data."],"distinction":"A DFIG converter handles only rotor slip power; a full-converter turbine passes all generator output through the converter.","facts":[{"label":"Generator type","value":"Wound-rotor induction, slip rings"},{"label":"Converter rating","value":"Typically about 25 to 35 per cent of turbine rating"},{"label":"Speed range","value":"Variable around synchronous speed"},{"label":"Preview","value":"Independent educational illustration; consult the applicable standard and project legend for the exact graphic"}],"references":[{"sourceId":"pub-electronics-infineon-inverter","relevance":"Public bidirectional AC/DC converter context relevant to the rotor-side back-to-back stage."},{"sourceId":"autodesk-generators","relevance":"Public generator symbol family context; the DFIG artwork is independently drawn."}],"related":["wound-rotor-induction-motor","full-converter-wind-turbine-generator","type-2-variable-slip-wind-turbine-generator","active-front-end-rectifier"],"artwork":"s28-doubly-fed-induction-generator","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","plainEnglish":{"title":"What does Doubly-fed induction generator mean?","introduction":"A doubly-fed induction generator has its stator connected directly to the turbine transformer while the rotor windings, reached through slip rings, connect to a back-to-back AC/DC/AC converter. The converter injects rotor currents at slip frequency, allowing variable speed of roughly plus or minus thirty per cent around synchronous speed and independent control of active and reactive power.","example":"On a single-line diagram the generator circle shows two connections: the stator branch to the main breaker and the rotor branch to a pair of converter blocks joined by a DC link. A crowbar or DC chopper is often shown on the rotor converter for fault protection, and a line filter or reactor sits on the grid-side converter.","drawings":"Because the converter only carries slip power, typically a quarter to a third of the turbine rating, the symbol does not imply full decoupling from the network. Short-circuit contribution, crowbar operation and ride-through capability depend on control settings that the diagram does not show.","terms":[{"name":"DC","meaning":"Direct current: electricity flowing in one direction."},{"name":"AC","meaning":"Alternating current: electricity whose direction changes periodically."},{"name":"Winding","meaning":"A coil of conductor inside an electrical machine or transformer."}],"diagram":"flow","steps":["Identify the device and form","Read the connections and state","Check the equipment reference"],"caption":"A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.","sources":[{"label":"Bidirectional three-/single-phase AC/DC PFC and inverter application note","url":"https://www.infineon.com/assets/row/public/documents/24/42/infineon-ac-dc-pfc-11-kw-high-efficiency-high-density-bidirectional-three-single-phase-inverter-applicationnotes-en.pdf"},{"label":"Generator symbol variants","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-09BE3BB5-9118-4302-8061-3888692E538F.htm"}],"detail":"A wound-rotor induction generator with the stator on the network and the rotor fed through a back-to-back converter sized for slip power. A DFIG converter handles only rotor slip power; a full-converter turbine passes all generator output through the converter.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/doubly-fed-induction-generator","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/doubly-fed-induction-generator.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"pub-electronics-infineon-inverter","title":"Bidirectional three-/single-phase AC/DC PFC and inverter application note","publisher":"Infineon Technologies","url":"https://www.infineon.com/assets/row/public/documents/24/42/infineon-ac-dc-pfc-11-kw-high-efficiency-high-density-bidirectional-three-single-phase-inverter-applicationnotes-en.pdf","type":"manufacturer","scope":"Public application context for actively switched AC/DC and inverter stages. Independent miniature topology illustrations have no copied product-specific values, wiring layouts or control implementation.","checkedOn":"2026-10-14","reuse":"link-only","relevance":"Public bidirectional AC/DC converter context relevant to the rotor-side back-to-back stage."},{"id":"autodesk-generators","title":"Generator symbol variants","publisher":"Autodesk","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-09BE3BB5-9118-4302-8061-3888692E538F.htm","type":"cad-reference","scope":"DC and three-phase synchronous generator categories.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Public generator symbol family context; the DFIG artwork is independently drawn."}]}