A method of controlling a wind turbine for the avoidance of edgewise vibrations. The method comprises the steps of determining a whirling mode frequency of a rotor blade of the wind turbine; determining a rotational frequency of the rotor blade corresponding to the speed of the rotor blade; determining a threshold value for the whirling mode frequency based on the rotational frequency; and, reducing the speed of the rotor blade if the whirling mode frequency substantially equals or is less than the threshold value.

The present invention relates to a method and a system for tracking the motion of a blade of a wind turbine. One embodiment relates to a blade motion tracking system for installation on a wind turbine blade, where the wind turbine blade comprises a blade root and a blade tip. The system comprises at least one light module comprising at least a first light source, preferably adapted to emit light in the direction of the blade root. An optical measuring device is provided, preferably located at the blade root, adapted to receive light emitted from the first light source(s). The optical measuring device is preferably a position sensitive detector identifying the position of the first light source relative to the position sensitive detector. A single light source located at the tip of the blade, close to the tip of the or towards the tip of the blade, is sufficient to measure deflection of the blade. Advantageously the first light source is modulated with a predefined modulation frequency such that light from the first light source can be distinguished from ambient light and thereby minimize the influence of the ambient light conditions during detection.

Provided are a yaw brake pad and a method of producing the same, which relate to the technical field of friction material. The yaw brake pad is prepared from, by weight, the following main ingredients: 70-75 parts of polyether ether ketone, 10-20 parts of carbon fiber, 3-5 parts of glass fiber and 3-5 of graphite. It alleviates the technical problem that the metal-based friction materials generally for producing current international and domestic yaw brake pads are likely to rust, harmful to dual discs, and produce screechy. It has not only significantly improved mechanical properties and high temperature tolerance, much lower hardness, less wear to dual discs, and lower noise, but also improved friction stability and adaptability to working conditions, and thus can effectively satisfy the demand of the wind driven generator for yaw braking at a low speed.

A set (200) of yaw claws (150) is provided comprising at least a first yaw (150a) claw and a second yaw claw (150b). The first yaw claw (150a) is to be used in a bearing ring (140) of a first yaw bearing (130) and the second yaw claw (150b) in a bearing ring (130) of a second yaw bearing (140). A circumference of the bearing ring (140) of the first yaw bearing (130) is substantially different from a circumference of the bearing ring (140) of the second yaw bearing (130). Each yaw claw (150) has a periphery, formed by a first side end (176), a second side end (178), an inner arc (172) and an outer arc (174), the inner arc (172) and the outer arc (174) being concentric with the respective bearing ring (140). At least two spring packs (166) are provided for pre-tensioning the yaw claw (150), respective spring pack centres (167) of the at least two spring packs (166) being arranged on a spring pack centreline (169) that is concentric with the inner arc (172) and the outer arc (174). A length of the spring pack centreline (169), measured from the first side end (176) to the second side end (178), of the first yaw claw (150a) is substantially equal to a length of the spring pack centreline (169) of the second yaw claw (150b).

A yaw braking assembly of a wind turbine is presented. Accordingly, the yaw braking assembly includes a bedplate support frame having an annular flange defining a plurality of recesses formed into a lower-most annular surface of the annular flange and extending at least partially through an axial thickness of the annular flange. Each of the plurality recesses define an open exterior circumferential side. The yaw braking assembly also includes a plurality of brake pads which are positioned within the plurality of recesses and configured to engage at least one race of an adjacent yaw bearing. The yaw braking assembly further includes a plurality of actuators for driving the plurality of brake pads to engage the yaw bearing.

Invention relates to renewable Wind energy combining drag and lift forces into usable torque, having adjustable blades panels with sub blades. Its unique feature is to convert reverse drag into usable lift and combine the two forces in to one cohesive force. The system comprises output drive rotor arranged on a tower base, with its rotating arms with blade panel assemblies mounted rotatably. Each blade panel assembly comprises an auxiliary rotary shaft having sub-blade panels pivotable at one or more pivot points with primary or secondary control arrangements for blocking and/or allowing wind to pass through the blade panels partially or fully. The system further includes sensors to collect control information, coupled to Main Control Unit (MCU) and secondary control arrangements, configured to provide one or more energy forms.

A computing system is configured to detect irregular yawing at wind turbines. To this end, the computing system (i) for each respective turbine of an identified cluster of wind turbines: (a) obtains yaw-activity data indicative of the respective turbine's yaw activity during a window of time, and (b) based on obtained yaw-activity data, derives a yaw-activity-measure dataset having measures of the respective turbine's yaw activity during time intervals within the window of time, (ii) based on the respective yaw-activity-measure datasets for the turbines in the cluster, derives a cluster-level yaw-activity-measure dataset, (iii) evaluates the respective yaw-activity-measure dataset for one or more turbines in the cluster as compared to the cluster-level yaw-activity-measure dataset, (iv) based on the evaluation, identifies at least one turbine of the cluster that exhibited irregular yaw activity, and (v) transmits, to an output device, a notification of the irregular yaw activity at the at least one turbine.

A bearing protection arrangement of a journal bearing arranged between a housing and a rotary component of a wind turbine. The bearing protection arrangement includes a wind speed monitor arranged to monitor wind speed in the vicinity of the wind turbine and to generate a wake-up signal when the wind speed exceeds a pre-defined minimum; a mode switch module of a backup battery arranged to provide restart power to an auxiliary of the wind turbine, which mode switch module is adapted to switch the backup battery from a normal-power mode into a low-power mode to conserve sufficient restart power after low wind-speed conditions, and to switch the backup battery from the low-power mode into a normal-power mode in response to the wake-up signal. A wind turbine and a method of protecting a journal bearing of a wind turbine during standstill.

Provided is a wind power generation system including: a wind power generation apparatus that includes at least a duct having a longitudinal cross section formed in a substantial streamline shape, the longitudinal cross section being cut along a central axis, an impeller placed in the duct, and a power generator that generates power by rotation of the impeller; an anemovane installed so as to be able to measure a wind direction and/or wind power in a vicinity of the wind power generation apparatus; a rotating pedestal that supports the wind power generation apparatus so as to be rotatable along a supporting surface; and a control device that controls a rotational angle of the rotating pedestal based on the wind direction and/or the wind power measured by the anemovane.

Provided is a wind turbine brake control device including: an electromagnetic brake for braking at least one of relative rotation between a pinion gear installed in a first structure and a ring gear installed in a second structure or rotation of a motor having the pinion gear mounted thereto, the first structure and the second structure constituting a movable section of a wind turbine; and a contactless relay disposed on a power supply line between a power supply for operation of the electromagnetic brake and the electromagnetic brake and configured to open and close the power supply line.