WINDMILL PITCH CONTROL DEVICE

PROBLEM TO BE SOLVED: To provide a windmill pitch control device capable of performing feathering and also continuously generating power even if an ordinary power source loses the ability to supply power.SOLUTION: A pitch controller transmits a control signal for pitch control which controls the charging and discharging of an accumulator 12 and also alters the pitch angle of a blade, and a motor controller 13 controls an electric motor 11 in accordance with the control signal from the pitch controller. An accumulator operation monitoring section 15 monitors the operation state of the accumulator 12. The motor controller 13 is supplied with power by being connected to an ordinary power source 111, and if the ordinary power source 111 loses the ability to supply power, the motor controller 13 uses power supplied from the accumulator 12 to control the electric motor 11 in accordance with the control signal and thereby continues pitch control. Control which alters the pitch angle of the blade in the direction in which wind pressure decreases is performed in accordance with the monitoring result of the accumulator operation monitoring section 15.