Blade pitch control system, wind turbine generator, and blade pitch control method

A wind turbine generator, comprising:

• a plurality of blades whose pitch angles are independently controllable;
• and
• a blade pitch control system including
• a pitch angle control part for generating and outputting a command value that indicates an amount of change in each of the pitch angles,
• actuators each of which changes the corresponding pitch angle based on the corresponding command value output from the pitch angle control part, and
• a measurement part for measuring a load imposed on each of the blades, wherein
• a set value indicating that wind received by the wind turbine generator has a biased wind speed distribution is set in advance in the pitch angle control part,
• when the load measured by the measurement part or a value based on the load is equal to or smaller than the set value, the pitch angle control part outputs the command value corresponding to the load and within predetermined limit values,
• only when the load or the value based on the load exceeds the set value, the pitch angle control part outputs the command value corresponding to the load and beyond the limit values, wherein the pitch angle control part outputs the command value beyond the limit values by accumulating a gain corresponding to the load or the value based on the load to the command value, and
• when the load measured by the measurement part or the value based on the load exceeds a predetermined threshold value higher than the set value, the gain becomes constant.

A blade pitch control method for a wind turbine generator that generates power through rotation of a rotor coupled to a plurality of blades whose pitch angles are independently controllable and includes a pitch angle control part for generating and outputting a command value that indicates an amount of change in each of the pitch angles, actuators each of which changes the corresponding pitch angle based on the corresponding command value output from the pitch angle control part, and a measurement part for measuring a load imposed on each of the blades, the blade pitch control method comprising:

• setting in advance a set value indicating that wind received by the wind turbine generator has a biased wind speed distribution;
• when the load measured by the measurement part or a value based on the load is equal to or smaller than the set value, outputting the command value corresponding to the load and within predetermined limit values;
• and
• only when the load or the value based on the load exceeds the set value, outputting the command value corresponding to the load and beyond the limit values, wherein
• the command value beyond the limit values is outputted by accumulating a gain corresponding to the load or the value based on the load to the command value, and
• when the load measured by the measurement part or the value based on the load exceeds a predetermined threshold value higher than the set value, the gain becomes constant.