Blade noise reduction device, blade, and wind turbine generator set

A blade noise reduction device, characterized in that the blade noise reduction device comprises:

• a plurality of sawtooth units arranged along a first direction, wherein each sawtooth unit comprises a primary tooth and secondary teeth extending along a second direction, and at least one secondary tooth is distributed on each of two sides of the primary tooth,
• wherein an addendum angle of the secondary tooth is smaller than an addendum angle of the primary tooth,
• the blade noise reduction device further comprises a connection body with a first side and a second side opposite to each other in the second direction, and the plurality of sawtooth units are disposed on the second side of the connection body,
• the connection body comprises a joint area and a trailing edge step, and the trailing edge step protrudes relative to the joint area on the suction surface of the blade noise reduction device and arranged at an end of the joint area close to the sawtooth unit, and
• the connection body further comprises an extension section arranged between the joint area and the sawtooth unit, and a thickness of the extension section is gradually decreased along the second direction.