Blade pitch controller, wind turbine generator, and method of controlling blade pitch

摘要

{Abstract} A hydraulic cylinder (48) is coupled to blades (20) of a wind turbine generator and actuated to change a pitch angle of the blade (20) . A variable displacement hydraulic pump (44) supplies hydraulic oil to the hydraulic cylinder (48), and a discharge pressure of the pump does not follow a load pressure. When the discharge pressure of the hydraulic pump (44) becomes a set pressure, a pressure control valve is opened to change a discharge amount of the hydraulic pump (44), and to make the discharge pressure of the hydraulic pump (44) to be a pressure smaller than a cut off pressure. Further, a setting control unit (60) sets the set pressure based on the hydraulic pressure that the hydraulic cylinder (48) requires such that the set pressure becomes a minimum pressure required to change the pitch angle to a predetermined angle by the hydraulic cylinder (48) . Thus, it is possible to reduce a differential pressure between the discharge pressure of the hydraulic pump (44) and the load pressure, and to reduce the power consumption.