This　paper　first　presents　the　Hopf　bifurcation　analysis　for　a　vector-controlled　doubly　fed　induction　generator　(DFIG)　which　is　widely　used　in　wind　power　conversion　systems.　Using　three-phase　back-to-back　pulse-width-modulated　(PWM)　converters,　DFIG　can　keep　stator　frequency　constant　under　variable　rotor　speed　and　provide　independent　control　of　active　and　reactive　power　output.　The　oscillatory　instability　of　the　DFIG　has　been　observed　by　simulation　study.　The　detailed　mathematical　model　of　the　DFIG　closed-loop　system　is　derived　and　used　to　analyze　the　observed　bifurcation　phenomena.　The　loci　of　the　Jacobian＇s　eigenvalues　are　computed　and　the　analysis　shows　that　the　system　loses　stability　via　a　Hopf　bifurcation.　The　eigenvalue　sensitivitiy　analysis　with　respect　to　machine　and　control　parameters　are　performed　to　assess　the　impact　of　parameters　upon　system　stability.　Moreover,　the　Hopf　bifurcation　boundaries　of　the　key　parameters　are　also　given　that　can　facilitate　the　tuning　of　those　parameters　to　ensure　stable　operation.　©2010　IEEE.