Flare-type tensile legs floating wind turbine base, offshore wind turbine and construction method

An offshore wind turbine, comprising a flare-type tension leg floating wind turbine foundation and a tower frame a blade and a wind turbine generator set installed on the floating wind turbine foundation;

• wherein the flare-type tension leg floating wind turbine foundation comprises:
• a top support platform configured to support the tower frame, the blade and the wind turbine generator set;
• a bottom support structure connected to a plurality of tension legs;
• at least three hollow upright columns connected between the top support platform and the bottom support structure and arranged around a vertical center line of the floating wind turbine foundation, each of the at least three upright columns being inclined outward from a lower end to an upper end with respect to the vertical center line of the floating wind turbine foundation;
• and
• a ballast adjusting system provided in the upright columns and/or the bottom support structure;
• and
• wherein the bottom support structure is formed by a polygonal pontoon, a plurality of outward protruding portions projecting from the polygonal pontoon, and bottoms of the upright columns are provided on the outward protruding portions respectively.