Patent application number | Description | Published |
20110084485 | Control method for a wind turbine - A method of controlling a wind turbine, where a control signal for a controllable parameter of the wind turbine is determined, and the rotor power coefficient, the torque coefficient, and/or a thrust coefficient of the wind turbine are estimated at time intervals. From this is determined a variation parameter reflecting the variation of the estimated rotor power, torque or thrust coefficient over time. The wind turbine is then controlled according to the control signal only if the variation parameter is below an alert threshold, and otherwise according to a modified control strategy. The control signal may have a power or torque reference signal for controlling the rotational speed of the turbine or a blade pitch reference signal. The modified control method may for instance entail stopping or de-rating the wind turbine. A control system configured to perform the above control method, and a wind turbine comprising such system are also disclosed. | 04-14-2011 |
20110178771 | METHOD FOR EVALUATING PERFORMANCE OF A SYSTEM FOR CONTROLLING PITCH OF A SET OF BLADES OF A WIND TURBINE - Methods of controlling a variable speed wind turbine generator connected to a power grid. The method may include measuring the frequency, f, of the power grid, controlling the speed of the generator for optimizing the power delivered to the power grid, and setting limits for the generator speed. The setting of the limits for the generator speed is performed in dependency of the measured frequency of the power grid. This provides a dynamical set of limits providing improved possibilities of optimizing the power production. | 07-21-2011 |
20130078093 | METHOD FOR DE-ICING THE BLADES OF A WIND TURBINE AND A WIND TURBINE WITH A DE-ICING SYSTEM - The invention refers to a method for de-icing a blade of a wind turbine. The de-icing is carried out by means of stalling the wind turbine and at least to a position where enough turbulence is created to induce vibrations in the blade allowing ice to break off. | 03-28-2013 |
20130121825 | CALLIBRATION OF WIND TURBINE SENSOR - A method is disclosed for calibrating a wind turbine sensor placed on a component of a wind turbine and where the wind turbine is of the type having a rotor with at least one pitchable wind turbine blade. The method comprises pitching one or more of the blades according to a predetermined pitch movement and detecting the response signal from the wind turbine sensor at least partly caused by the pitch movement. From this is then determined a characteristic sensor response value which upon comparison to a predetermined sensor calibration parameter forms the basis for a calibration of the wind turbine sensor if needed. The characteristic sensor response value may be determined from the pitch movement having been performed a number of times over a longer period of time. | 05-16-2013 |
20130140819 | METHOD FOR OPERATING A WIND TURBINE AT IMPROVED POWER OUTPUT - A method for operating a wind turbine is disclosed. The wind turbine comprises a rotor having a set of wind turbine blades, said rotor being mounted on a tower. The method comprises the steps of: Providing a curve defining optimal pitch angle as a function of tip speed ratio for the wind turbine blades or as a function of wind speed. Modifying at least a part of said optimal pitch angle curve by applying a safety buffer, e.g. at tip speed ratios and/or pitch angles where there is a risk that the blades may stall and/or that overload is caused to the wind turbine, thereby obtaining a safety modified pitch angle curve. Operating the wind turbine in accordance with the safety modified pitch angle curve. Measuring one or more parameters providing information regarding wind conditions and/or loads on one or more components of the wind turbine, during operation of the wind turbine. Adjusting the safety buffer, based on said measurements, thereby obtaining an adjusted pitch angle curve, and operating the wind turbine in accordance with the adjusted pitch angle curve. The safety buffer is applied in order to ensure that the blades of the wind turbine do not stall and/or that the wind turbine is not overloaded, but it has the effect that the wind turbine is operated in a suboptimal manner from an energy production view. Since the safety buffer is adjusted based on measured parameters, it can be reduced if it is detected that the actual operating conditions are less severe than expected. This allows the wind turbine to be operated in a more optimal manner, thereby increasing the energy production of the wind turbine. | 06-06-2013 |
20130195657 | WIND TURBINE SYSTEM FOR DETECTION OF BLADE ICING - The invention relates to a method for detecting icing and other loadings on blades of wind turbines. Advantageously, the method utilizes existing wind turbine actuators, for example pitch actuators, far excitation of blade vibrations. Vibration sensors on the blade such as strain sensors or accelerometers measure the blade vibrations excited in response to the actively excised vibrations. By comparing the measured response with previously obtained reference responses, it is possible to determine if blade icing is present. | 08-01-2013 |
20130287568 | SUPERVISION OF CONTROLLER INSTABILITY IN A WIND TURBINE - A wind turbine including a controller configured to periodically enter an Eigen frequency detection mode in which the controller gain is incremented in a controlled manner to detect the Eigen frequencies. During normal operations, the controller output may be monitored to detect the Eigen frequency which, if detected, may allow damage control operations to be undertaken. | 10-31-2013 |
20140110941 | WIND FARM AND A METHOD OF OPERATING A WIND FARM - According to an aspect of the invention, a wind farm is provided. The wind farm includes a plurality of wind turbines and a wind farm controller. The controller is configured to detect a high wind condition from at least one wind turbine in the wind farm, reduce a parameter setpoint of at least one other wind turbine, and increase a cut-out wind speed threshold of the at least one other wind turbine. | 04-24-2014 |