Excessive　reactive　power　generated　by　the　filter　and　compensation　devices　of　rectifier　station　will　flow　into　the　AC　system　when　DC　bipolar　block　occurs,　which　brings　a　high　voltage　threat　to　doubly-fed　induction　generator　(DFIG)-based　wind　farms　at　the　sending-end.　This　paper　proposes　a　nonlinear　robust　tracking　control　(RTC)　strategy　to　enhance　the　high-voltage　ride　through　(HVRT)　capability　of　DFIG-based　wind　farms.　In　the　proposed　strategy,　the　nonlinear　characteristics　of　wind　farms　and　the　disturbance　attenuation　requirements　during　DC　bipolar　block　is　fully　considered.　The　RTC　problem　is　formulated　with　control　objective　of　absorbing　the　reactive　power　injected　into　the　AC　system,　and　state-dependent　Riccati　equation　(SDRE)　technique　is　adopted　to　obtain　an　approximate　solution.　Case　studies　are　performed　on　MATLAB/Simulink,　the　results　illustrate　the　proposed　HVRT　control　strategy　has　a　better　transient　performance　of　suppressing　overvoltage　under　Bipolar　Blocking　of　HVDC　System.　©　2020　The　Authors