A counterweight system for mounting a rotor blade on a balanced rotatable hub of a wind turbine is disclosed. The rotatable hub can have at least one blade root region configured to receive a blade root of the rotor blade, and also have a pitch system configured to rotate the rotor blade around a pitch axis. The counterweight system can have at least one support structure having a proximal end spaced apart from a distal end with the proximal end mountable to at least one blade root region of the rotatable hub. The at least one counterweight mass can be at least partially filled with fluid and coupled to the distal end of the at least one support structure. The at least one support structure can be arranged substantially parallel to the pitch axis such that the pitch system rotates the counterweight mass about the pitch axis.

Provided are a method and a system for controlling wind turbine shutdown. The method includes: obtaining, according to a preset sampling period, a grid voltage for a wind turbine, and sending the obtained grid voltage to an converter controller; determining, by the converter controller and based on the grid voltage, an operating condition of a power grid is power outage of power grid; sending, in a case that the power outage of power grid is determined, a signal indicating power outage of power grid to a main controller of a main control system of the wind turbine; and controlling, by the main controller in a case that the signal indicating power outage of power grid is received, a pitch system to perform a variable-rate feathering.

There is presented a wind turbine system, wherein the wind turbine system is comprising a support structure, a plurality of wind turbine modules mounted to the support structure wherein each of the plurality of wind turbine modules comprises a rotor, and wherein the wind turbine system further comprises a control system, wherein the control is arranged to execute a wind turbine system transition from a first system operational state of the wind turbine system to a second system operational state of the wind turbine system, and wherein the wind turbine system transition is performed by executing a plurality of wind turbine module transitions from a first module operational state of a wind turbine module to a second module operational state of the wind turbine module wherein the plurality of wind turbine module transitions are distributed in time with respect to each other.

Method of reducing loads acting on a wind turbine yaw system in a wind turbine comprising a nacelle (2), a rotor which comprises at least one rotor blade (3) with a pitch control system and further comprising a yaw system that comprises the steps of detecting a yaw misalignment (), enabling a yaw maneuver and performing a pitch control in order to reduce a yaw moment (Mz) acting on the wind turbine once the yaw misalignment () is detected and prior to enabling the yaw maneuver. Thus, when a yaw movement to reduce the yaw misalignment is commanded, the yaw moment (Mz) due to aerodynamic forces has been reduced by means of the pitch control and undesired yaw movements are prevented.

A method for operating a wind turbine includes operating, via a controller, the wind turbine according to a speed set point during normal operation of the wind turbine. The method also includes receiving, via the controller, a command to shut down the wind turbine or to curtail operation of the wind turbine. In response to receiving the command, the method includes initiating, via the controller, a shutdown procedure or a curtailment procedure of the wind turbine. During the shutdown procedure or the curtailment procedure of the wind turbine, the method includes dynamically adjusting a rate of change of the speed set point as a function of a speed tracking error, which corresponds to a difference between an actual rotor speed of the wind turbine and the speed set point.

An improved wind turbine device of present invention provides continues rotation of propeller and prevents stopping or critical slowing of the propeller of the turbine that causes damage to the bearing and gear assembly and shortens the life of the turbine. The wind turbine device or system of present invention is comprising of a novel hollow propeller blades having a pair of reservoirs at the top and bottom of the propeller blades and a hydraulic pump configured between the reservoirs within the hollow propeller blades along with the wireless control unit that commands the pump to manipulate the fluid present within the reservoirs to create an imbalance within the hollow propeller causing the hollow propeller to keep from stopping. Also, the wireless control unit commands the pump to manipulate the fluid of the reservoirs in reverse direction in high wind condition to prevent the propeller from rotating excessively that may cause damage and loss of electricity.

A method and an apparatus for yaw control of a wind turbine under a typhoon. The method for yaw control may include: determining, before or when the typhoon comes, whether there is a fault in a yaw system of the wind turbine; performing a normal yaw control over the wind turbine according to the wind direction, if determination is negative; and performing a yaw control corresponding to the fault on the wind turbine according to the wind direction, if determination is positive. The yaw control corresponding to the fault is performed before or when the typhoon comes, in case of one of a yaw drive mechanism fault, an electronic brake mechanism fault, or a hydraulic brake mechanism fault. The wind turbine is downwind oriented and yaw load reduction is achieved.

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.

Provided are a method and a system for controlling wind turbine shutdown. The method includes: obtaining, according to a preset sampling period, a grid voltage for a wind turbine, and sending the obtained grid voltage to an converter controller; determining, by the converter controller and based on the grid voltage, an operating condition of a power grid is power outage of power grid; sending, in a case that the power outage of power grid is determined, a signal indicating power outage of power grid to a main controller of a main control system of the wind turbine; and controlling, by the main controller in a case that the signal indicating power outage of power grid is received, a pitch system to perform a variable-rate feathering.

This load estimating device for a rolling bearing comprises: a vibration sensor for measuring vibrations of the rolling bearing during rotation; a rotational speed sensor for measuring the rotational speed of the rolling bearing during rotation; a deriving means for deriving a vibration value for a predetermined vibration frequency, using vibration information measured by the vibration sensor; and an estimating means for estimating a load acting on the rolling bearing, said load corresponding to the rotational speed measured by the rotational speed sensor and the vibration value derived by the deriving means, using a table defining a correspondence relationship between the load acting on the rolling bearing, the vibration value for the predetermined vibration frequency, and the rotational speed.