A drive assembly for adjusting the pitch of a wind turbine blade comprises a stator having a cylindrical body and a drive member positioned at least partially within the cylindrical body and movable along an axis thereof. A mounting pin extends through an aperture in a wall of the cylindrical body for pivotally mounting the stator to a wind turbine structure.

Provided is a hydraulic pump arrangement including a plurality of motor-pump units connected to a common confluence, wherein each motor-pump unit of the hydraulic pump arrangement includes a pump realized provide pressurized fluid at its outlet; a motor arranged to drive the pump; a bypass valve configured to relieve pressure at the pump outlet; and wherein the hydraulic pump arrangement further includes a controller configured to receive a feedback signal from each motor-pump unit and to actuate the bypass valve of a motor-pump unit on the basis of the motor speed of that motor-pump unit. Further provided is a method of operating such a hydraulic pump arrangement, and a wind turbine including a number of such hydraulic pump arrangements.

There is provided a pitch control system (210) for controlling a pitch force system (220) for pitching a blade (103) of a wind turbine (100), the pitch control system (210) being arranged for activating (682) an auxiliary pitch force subsystem (224) at an initiation point in time where a main pitch force is sufficient to pitch the blade (103) into a target pitch value. An advantage thereof may be that tracking of a target pitch value may be improved and the impact on the pitch force system (220) may be reduced. In aspects, there is furthermore presented a hydraulic pitch system (206), a wind turbine (100), a method and a computer program product.

The present disclosure relates to wind turbines, pitch adjustment cylinders for adjusting a pitch angle of a blade of a wind turbine, to methods of assembling pitch adjustment cylinders, and to use of pitch adjustment cylinders in wind turbine, wherein the pitch adjustment cylinder comprises a cylinder barrel having an first cylinder barrel thread with a first thread pitch, a piston arranged movably in the cylinder barrel and extending out of the cylinder barrel for coupling to one of the blade and a hub of the wind turbine, a trunnion adapted to couple the cylinder barrel to the other one of the blade and the hub of the wind turbine, wherein the cylinder barrel extends through the trunnion, the trunnion has an first trunnion thread with a second thread pitch being different from the first thread pitch; and a sleeve arranged at least partially between the trunnion and the cylinder barrel, wherein the cylinder barrel extends through the sleeve, the sleeve has an inner sleeve thread with the first thread pitch and is engaged with the first cylinder barrel thread and the sleeve has an outer sleeve thread with the second thread pitch and is engaged with the first trunnion thread.

This invention discloses in particular an actuation cylinder (10) for controlling the movement of a ring-gate (40) of a hydraulic machine, said actuation cylinder (10) comprising a body (18) forming a first chamber (22) provided with a first duct (26) and a second chamber (24) provided with a second duct (28) which are designed to receive an actuating fluid through said first duct (26) and said second duct (28), said chambers being separated from one another by a piston (20) connected to an actuating rod (14) and able to move in said body in a first direction in which the volume of the second chamber increases while the volume of the first chamber decreases, and in a second direction in which the volume of the second chamber decreases while the volume of the first chamber increases, said piston being provided with a rod (30) connected in said second chamber to an area (20b) of the piston turned toward said second chamber, said area (20b) having a surface less than an area (20a) of the piston turned toward the first chamber.

A hydraulic circuit for a wind turbine is provided. The hydraulic circuit includes: a fixed displacement pump including a suction input and a delivery output, a pump motor for driving the fixed displacement pump, a pressure line hydraulically connected to the delivery output of the fixed displacement pump for delivering an output flow and/or an output pressure generated by the fixed displacement pump towards at least a consumer circuit, a bypass valve including a valve input hydraulically connected to the delivery output of the fixed displacement pump, wherein the bypass valve includes a variable opening for controlling the output flow or the output pressure delivered by the fixed displacement pump towards the consumer circuit(s).

System and method for controlling operation of a hydroelectric production system comprising electrical actuators operably connected at opposite positions of a gate operating ring for rotating the wicket gates to a desired position. The system receives a single control signal designed for a hydraulic system comprising hydraulic actuators operably connected to a single fluid reservoir and configured to work in tandem to produce simultaneous and opposite axial movements. The system comprises a control interface adapted to produce new control signals, each new signal being intended to a different electrical actuator to cause the electrical actuators to have axial movements which are identical in speed and in opposite directions to substantially imitate the exact movement of the hydraulic actuators onto the gate operating ring. The system is configured to introduce a dampening effect to reduce sudden acceleration and deceleration which is purposely used in hydraulic systems to overcome friction and static effects.

A method for detaching or installing a rotor blade from or to a hub of a wind turbine includes positioning the rotor blade toward a ground location between a three o'clock position and a nine o'clock position. The method also includes mounting a mechanical arm to an uptower location of the wind turbine. Further, the mechanical arm includes a torqueing tool at a distal end thereof. Thus, the method also includes removing or installing, via the torqueing tool, each of the plurality of hub fasteners so as to detach or attach the rotor blade from or to the hub.

Provided is a safety stop valve arrangement of a hydraulic blade pitch system of a wind turbine, including an accumulator arrangement connected over a hydraulic line to a piston of the hydraulic blade pitch system; a redundant set of safety valves arranged between the accumulator arrangement and the piston; a small-orifice restriction nozzle arranged to determine a first rate of hydraulic fluid flow in response to a safety stop input; at least one speed-select valves arranged; and at least one large-orifice restriction nozzle arranged to determine a second rale of hydraulic fluid flow in response to a positive rotor acceleration input, wherein the second rate of fluid flow is faster than the first rate of fluid flow. A safety stop assembly of a wind turbine with hydraulic blade pitch system and a method of performing a safety stop sequence is also provided.

Provided is an arrangement and a method to detect an oil leakage between a first section and a second section of a hydraulic cylinder. A movable piston is arranged between the first and second section in a way that the piston changes position between the sections. The change in position is done in dependency of a difference between a first force, which acts at the first section on a first cross sectional area of the piston, and a second force, which acts at the second section on a second cross sectional area of the piston. The first section comprises hydraulic oil with a predefined first pressure, while the first force is calculated based on this pressure and based on the first area. The second section comprises hydraulic oil with a predefined second pressure, while the second force is calculated based on this pressure and based on the second area.