Method and apparatus for controlling noise levels of a turbine with minimal loss in energy yield

A method for controlling a tip speed of a blade of a wind turbine, the blade attached to a hub having a shaft, and an electrical generator coupled thereto, said method comprising:

• monitoring with a sensor torque of the electrical generator or power output of the electrical generator to determine wind speed,
• maintaining a first substantially constant rotational speed of the tip of the blade during variable wind speeds above a first predetermined wind speed and below a second predetermined wind speed, the first predetermined wind speed being less than the second predetermined wind speed;
• and
• maintaining a second substantially constant rotational speed of the tip of the blade during variable wind speeds above the second predetermined wind speed, the second substantially constant rotational speed of the tip of the blade being greater than the first substantially constant rotational speed of the tip of the blade.