Methods of operating a variable speed wind turbine as a function of a wind speed, the wind turbine having a rotor with a plurality of blades, and one or more pitch mechanisms for rotating the blades. The method comprising a sub-nominal zone of operation for wind speeds below the nominal wind speed and a supra-nominal zone of operation for wind speeds above the nominal wind speed. In the supra-nominal zone, the blades are pitched so as to maintain the rotor speed substantially constant, and a tip speed ratio of the wind turbine is substantially continuously being determined and wherein an instantaneous minimum pitch angle is substantially continuously being determined based on the instantaneous tip speed ratio, and the blades are never pitched below the instantaneous minimum pitch angle. The disclosure further relates to a wind turbine suitable for carrying out such methods.

The present invention relates to a floating wind energy harvesting apparatus for offshore installation, comprising an elongated wind turbine body extending along a longitudinal wind turbine body axis; at least one blade attached to the wind turbine body for converting wind energy to rotation of the wind turbine body around the longitudinal wind turbine body axis; an energy converter coupled to the wind turbine body for converting the rotation of the wind turbine body to electrical energy; and a braking arrangement for controllably reducing a rotational speed of the wind turbine body. The braking arrangement comprises an inlet; an outlet; a water transporting arrangement coupled to the wind turbine body to transport water from the inlet to the outlet in response to rotation of the wind turbine body; and an access control arrangement for controllably preventing water from passing through the water transporting arrangement.

A wind turbine and associated control method includes a controller configured with a high speed shaft brake in the generator gear train. The controller receives an input signal corresponding to rotational speed of the high speed shaft, wherein upon the high speed shaft reaching a predefined rotational speed and under a braking condition that calls for the rotor to come to a complete standstill, the controller generates an activate signal to activate the brake. An interlock system is in communication with the low speed shaft sensor and the controller and is configured to override the activate signal when the rotational speed of the low speed shaft is above a threshold value.

A method for operating a wind turbine during partial load operation includes determining a power output of the wind turbine. The method also includes determining whether the power output is below a rated power of the wind turbine. If the power output is at the rated power, the method includes maintaining a speed set point of the wind turbine equal to a rated speed set point. However, if the power output is below the rated power, then the method includes varying, via a controller, the speed set point of the wind turbine as a function of a torque of the wind turbine in a non-monotonic torque-speed relationship.

A gas turbine engine assembly includes a fan section delivering air into a main compressor section. The main compressor section compresses air and delivers air into a combustion section. Products of combustion pass from the combustion section over a turbine section to drive the fan section and main compressor sections. A gearbox is driven by the turbine section to drive the fan section. A pylon supports the gas turbine engine. An environmental control system includes a higher pressure tap at a higher pressure location in the main compressor section, and a lower pressure tap at a lower pressure location. The lower pressure location being at a lower pressure than the higher pressure location. The lower pressure tap communicates to a first passage leading to a downstream outlet and a compressor section of a turbocompressor. The higher pressure tap leads into a turbine section of the turbocompressor such that air in the higher pressure tap drives the turbine section to in turn drive the compressor section of the turbocompressor. The pylon includes a lowermost surface and the higher pressure tap does not extend above a plane including the lowermost surface. A combined outlet of the compressor section and the turbine section of the turbocompressor intermixes and passes downstream to be delivered to an aircraft use. An environmental control system is also disclosed.

A method for operating a wind turbine includes: determining a value of a wind speed of an incident air mass at the wind turbine; if the determined value of the wind speed is greater than a first threshold value for the wind speed: reducing a rotational speed of a rotor of the wind turbine, and maintaining or increasing a generator torque acting upon the rotor; if the determined value of the wind speed is greater than a second threshold value for the wind speed, the second threshold value being greater than the first threshold value: reducing the rotational speed of the rotor, and reducing the generator torque acting upon the rotor.

A power converter assembly for an electrical power system connected to a power grid includes a rotor-side converter configured for coupling to a generator rotor of a generator of the electrical power system, a line-side converter electrically coupled to rotor-side converter via a DC link, and a dynamic brake assembly electrically coupled to the DC link. The line-side converter is configured for coupling to the power grid. The dynamic brake assembly includes a plurality of switching devices connected in parallel and a plurality of inductors electrically coupled between the plurality of switching devices.

A power converter assembly for an electrical power system connected to a power grid includes a rotor-side converter configured for coupling to a generator rotor of a generator of the electrical power system, a line-side converter electrically coupled to rotor-side converter via a DC link, and a dynamic brake assembly electrically coupled to the DC link. The line-side converter is configured for coupling to the power grid. The dynamic brake assembly includes a plurality of switching devices connected in parallel and a plurality of inductors electrically coupled between the plurality of switching devices.

A device and a method of controlling blade instabilities of a wind turbine is provided. The method including the following steps: defining at least one preliminary overspeed threshold value; defining a fluttering rotor speed at and above which a predetermined fluttering of at least one of the blades occurs, the fluttering rotor speed is defined as a function of the pitch angle and/or as a function of the wind speed; setting a final overspeed threshold value to be equal to or smaller than a minimum rotor speed of the at least one preliminary overspeed threshold value and the fluttering rotor speed at the actual pitch angle and/or at the actual wind speed; and controlling the rotor speed to not exceed the final overspeed threshold value.

A method for controlling a wind turbine is disclosed, the wind turbine comprising a set of wind turbine blades (1), each wind turbine blade (1) being provided with at least one air deflector (2) being movable between an activated position in which it protrudes from a surface of the wind turbine blade (1) and a de-activated position. The occurrence of an event causing a change in operational conditions is registered, and a new operating state for the wind turbine is determined, the new operating state meeting requirements of the changed operational conditions. The air deflectors (2) of the wind turbine blades (1) and pitch angles of the wind turbines blades (1) are controlled in order to reach the new operating state for the wind turbine, and in such a manner that the control of the pitch angles of the wind turbine blades (1) is performed while taking information regarding the control of the air deflectors (2) into account.