Patent ID: 8439638
Filing Date: 2013-05-14
Classification: F03D,F05B,Y02E

Abstract:
1. A blade pitch controller for a wind turbine generator that generates power by rotation of a rotor to which a plurality of blades are turnably coupled, the blade pitch controller comprising: a hydraulic cylinder coupled to the blades and configured to be actuated to change a pitch angle of the blades; a variable displacement hydraulic pump configured to supply hydraulic oil to the hydraulic cylinder, a discharge pressure of the pump not following a load pressure, the hydraulic oil not being discharged at a pressure greater than a previously determined first pressure; a valve configured to be opened to change a discharge amount of the hydraulic pump and to make the discharge pressure of the hydraulic pump to be a second pressure when the discharge pressure of the hydraulic pump becomes a set pressure, the second pressure corresponding to the set pressure; a pitch angle setting unit configured to set a set value of a pitch angle of the blade; a calculating unit configured to calculate a deviation angle of a first pitch angle from a second pitch angle, the first pitch angle corresponding to the set value set by the pitch angle setting unit, the second pitch angle corresponding to an actual pitch angle of the blade; and a discharge pressure setting unit configured to set, when the variable displacement hydraulic pump supplies the hydraulic oil at the second pressure, the set pressure on a basis of the deviation angle calculated by the calculating unit such that the hydraulic cylinder generates a hydraulic pressure required for changing the actual pitch angle to the first pitch angle.