A method for transitioning a wind turbine into an energy harvesting mode in which the wind turbine generates electrical power from wind energy is provided. An energy storage system supplies electrical power to an auxiliary system when the wind turbine is not generating or receiving electrical power sufficient for supplying the auxiliary system. The method includes operating the wind turbine in a first operating mode in which an electrical power supply is ceased; obtaining environmental data including at least one of wind data and meteorological data; and determining if the obtained environmental data meets a predefined condition. If the predefined condition is met, a transition of the operation of the wind turbine into the energy harvesting mode is caused, wherein transitioning the operation into the energy harvesting mode comprises supplying electrical power from the energy storage system to the one or more auxiliary power consumers of the first group.

The invention relates to a method for controlling a wind turbine that comprises a generator, is provided to feed electrical power into an electricity supply grid but has not yet been connected to the electricity supply grid, comprising the steps: generating electrical power using the generator and supplying electrical elements of the wind turbine with the power generated, and to a wind turbine for generating electrical power from the wind and for feeding the electrical power generated into an electricity supply grid, wherein a method according to one of the preceding claims is carried out.

A horizontal-shaft wind machine having improved low wind speed performance and greater overall efficiency consists of multiple rotors, wherein each successive rotor is larger in diameter than the previous rotor moving from the most windward rotor to the most leeward rotor. Each rotor may be coupled to a separate concentric shaft, and all rotors may rotate in the same direction with the output shafts of each rotor coupled via an overrunning clutch to a single shaft, the output of which is used to drive the load. Winglets attached to the leading edge and tip of the rotor sails improve low wind startup torque.

A wind turbine includes a plurality of wind turbine blades; a plurality of hydraulic actuators for controlling respective pitch angles of the wind turbine blades; a first tank storing control oil for the hydraulic actuators; a first hydraulic pump disposed between the plurality of hydraulic actuators and the first tank, for pumping the control oil; a plurality of valves each of which is provided for corresponding one of the hydraulic actuators, for controlling a supply state of the control oil to the hydraulic actuator; and a control part for controlling each of the valves. The control part is configured to, in warm-up of a pitch hydraulic system of the plurality of wind turbine blades, perform an oil transfer operation of changing the pitch angle of the wind turbine blade from a feather side toward a fine side and then returning the pitch angle to the feather side.

A horizontal-shaft wind machine having improved low wind speed performance and greater overall efficiency consists of multiple rotors, wherein each successive rotor is larger in diameter than the previous rotor moving from the most windward rotor to the most leeward rotor. Each rotor may be coupled to a separate concentric shaft, and all rotors may rotate in the same direction with the output shafts of each rotor coupled via an overrunning clutch to a single shaft, the output of which is used to drive the load. Winglets attached to the leading edge and tip of the rotor sails improve low wind startup torque.

Several embodiments include a system and method for providing thrust recovery in an aircraft engine. The system and method enables a wider range of safe operation for aircraft where the aircraft engine is rapidly reactivated from a substantially deactivated state. The method thereby reduces noise output and fuel usage during descent and shortens runway lengths and occupancy time required for landing. Thrust recovery is provided via the use of stored bleed air being re-injected back into the aircraft engine. An onboard air storage tank and a system of valves facilitating this method are disclosed.

The present invention relates to a method of decelerating a turbine rotor of a turbine engine. At least one electric motor is engaged with the turbine rotor. A braking system, preferably the starting system, is engaged with the at least one electric motor, preferably the generator of the turbine engine, so as to use the at least one electric motor to apply a negative (braking) torque on the turbine rotor. The method includes after flame off, the braking system being used for dissipating kinetic energy available in the turbine engine after flame off by means of the at least one electric motor.

A blade adjusting device for a wind turbine is connected to a plant safety chain and can open and close the plant safety chain by activating a switch. If a fault is detected in one of the blade adjusting devices, the respective control unit can open the plant safety chain. By opening the safety chain, a signal is sent to the blade adjusting devices, and so all the blade adjusting devices initiate a synchronous safety operation of at least two rotor blades when the signal is received.

A method including operating the wind turbine in a first operating mode which an auxiliary system of the wind turbine is supplied with electrical power from an energy storage system of the wind turbine, wherein in the first operating mode, a first group auxiliary power consumers of the auxiliary system and a second group auxiliary power consumers of the auxiliary system are supplied with electrical power from the energy storage system. Upon fulfillment of a predefined condition, the wind turbine is operated in a second operating mode wherein the power supply from the energy storage system to the first group of auxiliary power consumers is ceased. Upon a charging state of the energy storage system reaching or dropping below a predetermined charging level, the wind turbine may be operated in a third operating mode in which auxiliary power supply is ceased.

Several embodiments include a system and method for providing thrust recovery in an aircraft engine. The system and method enables a wider range of safe operation for aircraft where the aircraft engine is rapidly reactivated from a substantially deactivated state. The method thereby reduces noise output and fuel usage during descent and shortens runway lengths and occupancy time required for landing. Thrust recovery is provided via the use of stored bleed air being re-injected back into the aircraft engine. An onboard air storage tank and a system of valves facilitating this method are disclosed.