BLADE PITCH CONTROLLER, WIND TURBINE GENERATOR, AND METHOD OF CONTROLLING BLADE PITCH

摘要

A hydraulic cylinder is coupled to blades of a windturbine generator and actuated to change a pitch angle ofthe blade. A variable displacement hydraulic pumpsupplies hydraulic oil and a discharge pressure of thepump does not follow a load pressure. When the dischargepressure of the hydraulic pump reaches a set pressure, apressure control valve is opened to change a dischargeamount of the hydraulic pump, and to reduce the dischargepressure to be smaller than a cut off pressure. Further, asetting control unit sets the set pressure based on thehydraulic pressure that the hydraulic cylinder requiressuch that the set pressure becomes a minimum pressurerequired to change the pitch angle to a predetermined angleby the hydraulic cylinder. Thus, a reduction in adifferential pressure between the discharge pressure andthe load pressure and in the power consumption is possible.