A hydraulic pitch drive system for controlling a blade pitch angle of a wind turbine rotor has a hydraulic cylinder, for actuating blade pitch rotation, with a piston-side and rod-side. A first hydraulic proportional valve controls hydraulic fluid flow from a pressure port to the cylinder in response to a primary control signal. In an cylinder extending mode, the pressure port via the first hydraulic proportional valve is connected to the piston-side. The rod-side is connected to the pressure port via a non-return valve. A first control module provides the primary control signal in response to a pitch angle positioning request. A second hydraulic proportional valve controls hydraulic fluid flow from the rod-side to tank port independent of the first hydraulic valve, in response to a secondary control signal. A second control module provides the secondary control signal for controlling the second proportional valve in a hydraulic cylinder extending mode.

A method of controlling a wind turbine, wherein a minimum required hydraulic pressure represents a hydraulic pressure of at least one accumulator of the wind turbine which is required to pitch at least one blade of the wind turbine which is associated with the accumulator into a stop position of the wind turbine, and wherein a pitch angle represents a pitch angle of a normal of the at least one blade of the wind turbine relative to an incoming wind direction. The method includes (a) determining a minimum requirement function of the minimum required hydraulic pressure dependent on the pitch angle, (b) detecting a current hydraulic pressure in the at least one accumulator at a current pitch angle of the at least one blade, and (c) controlling the wind turbine such that the current hydraulic pressure is above the minimum required hydraulic pressure at the current pitch angle.

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 gearbox for a wind turbine, which has at least one first and one second shaft, which are arranged parallel to each other and supported in roller bearings. A preload device for the roller bearings is provided, wherein the preload device generates a preload force between the first and the second shaft and is supported with one end on the shafts in each case.

A wind turbine having a nacelle with a stationary region and a rotor, at least one blocking unit for blocking the rotor, and an access control system is provided. The access control system controls a locking of at least one access door to at least one closed-off region in the wind turbine depending on a blocking of the rotor by means of the least one blocking unit. The access control system has a key transfer system and a hydraulic control unit for controlling the blocking unit. The key transfer system has a hydraulic key unit for preventing an unintentional activation of the hydraulic unit and an access door key unit for locking or unlocking the access door. The key transfer system has at least one first and second key, the hydraulic control unit being locked or unlocked by means of the first key, and the access door key unit being locked or unlocked by means of the second key, and the key transfer system also having a fan key unit for activating or deactivating a fan, the first key of the hydraulic key unit being used to lock and unlock the fan key unit and a fan key being used as a second key for locking or unlocking the access door key unit.

The present invention relates to a hydraulic pitch system for pitching a blade of a wind turbine having a hub by means of a hydraulic fluid. The system comprises at least one hydraulic cylinder for adjusting a pitch angle of the blade, the hydraulic cylinder comprising a pitch piston movable in the hydraulic cylinder, and a first port and a second port arranged on each side of the pitch piston, and an accumulator hydraulically connected to the cylinder. The system further comprises a pitch safety system adapted to maintain the blade in a predetermined pitch angle when a person is entering the hub of the wind turbine for service and/or maintenance, the pitch safety system comprising a first valve which by activation releases a pressure in the hydraulic pitch system by draining off the accumulator for the hydraulic fluid until the pressure has reached a predetermined pressure level.

Provided is a method of controlling a rotational speed of a rotor of a wind turbine having a rotor with blades connected thereon, at least one blade including a blade profile changing equipment, the method including: changing the blade profile dependent on a rotational speed deviation of an actual rotational speed of the rotor or the generator rotor from a reference rotational speed.

The invention relates to a wind energy system with at least one pitch adjustment system for adjusting the pitch of at least one rotor blade of the wind energy system, wherein the pitch adjustment system comprises at least one electrohydraulic drive that comprises an unregulated electromotor rotating in one direction of rotation for generating pressure.

The disclosure relates to controlling blade pitch in a wind turbine that has a plurality of rotor blades and a hydraulic pitch system for adjusting a pitch of each of the rotor blades. The disclosure describes a method comprising obtaining a measurement indicative of a current level of hydraulic pressure available in the hydraulic pitch system, and determining, based on the obtained measurement, an adaptive pitch reference rate indicative of a rate at which the pitch of the rotor blades is to be adjusted by the hydraulic system. The method includes controlling the hydraulic pitch system to adjust the pitch of the rotor blades in accordance with the determined adaptive pitch reference rate.

The invention introduces a wave energy conversion system that utilizes the kinetic energy of water body waves, transforming it into usable energy. The system is innovatively designed with two buoyant bodies that, through their multi-dimensional non-parallel arrangement, form a recess optimized for capturing wave energy from. One of the system's distinctive features is its capacity to passively modify the relative orientation of the buoyant bodies, to become more parallel, in response to large wave forces, which serves to maintain stability under varying sea conditions. Concurrently, the system boasts advancements in the realm of installation and maintenance, presenting a streamlined approach that significantly alleviates the challenges traditionally associated with deploying and upkeeping marine energy converters. These aspects together underscore the system's novel contributions to enhancing the operational efficiency and sustainability of wave energy conversion technology.