Methods and apparatus for controlling rotational speed of a rotor

A wind turbine comprising:

• a rotor comprising a hub, at least one rotor blade coupled to said hub, and a rotor shaft coupled to said hub for rotation therewith;
• a blade pitch actuator coupled to said at least one rotor blade for controlling an angle of pitch of said at least one rotor blade;
• an electrical generator coupled to said rotor shaft, said electrical generator configured to couple to an electrical load;
• a frequency converter coupled to said electrical generator;
• and
• a processor coupled to said blade pitch actuator and coupled to said frequency converter, said processor configured to control a speed of said rotor by:
• controlling a torque of said electrical generator using said frequency converter to thereby control a torque of said rotor shaft;
• alternating between changing an angle of pitch of said at least one rotor blade in a plurality of successive steps using said blade pitch actuator and maintaining the angle of pitch of said at least one rotor blade substantially constant;
• and
• maintaining a substantially constant rotational speed of said rotor during variable wind speeds above a predetermined rated wind speed.