A method of retrofitting a wind turbine having a tower and a first energy generating unit with a second energy generation unit is disclosed. The wind turbine has been operated for a first period of time at a first tower life rate and has a first tower life expectancy design value. The method includes determining the tower life of the wind turbine tower used during the first period of time; determining the remaining tower life of the wind turbine tower; replacing the first energy generating unit with the second energy generating unit; and operating the retrofitted wind turbine at a second tower life rate less than the first tower life rate so as to extend the life expectancy value of the tower beyond the first tower life expectancy design value.

The invention relates to a method for damping drive train oscillations of a VSM configured wind turbine. The method comprises determining a drive train damping power signal based on speed signal representing a generator speed, determining a power deviation based on a combination of a power reference for a desired power production, the drive train damping power-signal, a grid power supplied by the line side converter to the grid and a damping power, determining a virtual synchronous machine angle based on the power deviation so that the derivative of the virtual synchronous machine rotational speed is indicative of the power deviation, determining a converter reference for controlling the line side converter to generate the desired active power based on the virtual synchronous machine angle and a voltage reference for a voltage amplitude to be generated by the line side converter, and applying the converter reference to the line side converter.

Methods and apparatus for reducing peak power consumption of a grid connected power plant having a plurality of wind turbines. In response to determining that a power production value of the power plant is below a power threshold, one method includes: after a first time delay of a first group of one or more wind turbines, control the first group to operate in a power saving mode for a predefined first power saving period; and after a first time delay of a second group of one or more other wind turbines, control the second group to operate in the power saving mode for a predefined second power saving period. The first time delay of the first group is less than the first time delay of the second group and the power saving mode inhibits a power consuming activity for the wind turbines operating in the power saving mode.

A wind turbine rotor blade assembly which incorporates automatic-aerodynamic control of the blade pitch angle is disclosed. The airfoil of the rotor blade (110) is free to rotate about a strategically located longitudinal blade axis which forms the spar stub (115) and is connected to the hub (120) of a horizontal axis wind turbine. The location of this blade axis is precisely set with respect to the turbine blade's aerodynamic center and center of mass. By further incorporating a reflexed airfoil with positive pitching moment this arrangement aerodynamically induces an automatic and self-regulating alignment of the rotor blade pitch such that the airfoil is always operating at or near optimal angle of attack. Details are disclosed on these strategic relationships which enable the successful operation of the new blade design.

Techniques for controlling rotor speed of a wind turbine. One technique includes defining a system model describing resonance dynamics of a wind turbine component, such as a wind turbine tower, where the system model has a nonlinear input term, e.g. a periodic forcing term. A transform is applied to the system model to obtain a transformed model for response oscillation amplitude of the wind turbine component, where the transformed model has a linear input term. A wind turbine model describing dynamics of the wind turbine is then defined, and includes the transformed model. A model-based control algorithm, e.g. model predictive control, is applied using the wind turbine model to determine at least one control output, e.g. generator torque, and the control output is used to control rotor speed of the wind turbine.

A test and control apparatus, system and method for a wind farm, are provided. The test and control apparatus includes a first communication interface, a second communication interface, and a processor card. The processor card receives, via the first communication interface, a frequency regulation instruction issued by the grid scheduling server, receives operation information of the wind power generation unit via the second communication interface, and calculates, based on the operation information of the wind power generation unit, a first frequency regulation capability of the wind power generation unit performing a frequency regulation without using the first energy storage battery. The processor card sends the frequency regulation instruction to the wind power generation unit without using the first energy storage battery, in a case that the first frequency regulation capability of the wind power generation unit satisfies a requirement of the frequency regulation instruction.

A method for determining an available power of a wind farm, wherein the wind farm comprises a plurality of wind power installations with a rotor having rotor blades, the blade angle of which can be adjusted is provided. A wind farm which is set up to carry out the method for determining an available power is provided. The method comprises providing a shading matrix which determines at least one effective wind speed of each of the wind power installations in the wind farm as a function of at least one wind speed and wind direction and wind farm throttling using a park wake model. The method makes it possible to accurately determine an available power of a wind farm even when the wind farm is operated with throttled power.

The invention relates to a drive system for interior wind turbines, consisting of a rotatable tower (5) with a rotor mounted at hub height, the generator (16) being located at the foot of the tower (5) on a drive/generator platform (13) and the rotor torque being transferred from above downwards to the generator (16). Particular requirements are placed on such a drive system as the height of the interior wind turbine increases. A steel-wire-cable-reinforced flat belt (18) is used as a transfer element, the ends of which are joined in a particular way to form an endless belt the pretensioning of which is regulated dependent on the properties of the wind, and automatic monitoring is provided which executes an immediate controlled shut-down of the drive system if damage occurs.

Techniques for controlling the yaw of a wind turbine system by controlling a plurality of yaw drive actuators. Based on a requested motor speed reference as an input signal, and a mean motor speed reference as a feedback signal, the method determines a required motor torque reference as an output signal for the plurality of yaw drive actuators. The plurality of yaw drive actuators rotates a nacelle or a structure comprising a plurality of nacelles such that an even load distribution is provided for the plurality of yaw drive actuators.

A portable system for converting wind energy into electrical energy is disclosed. The disclosed system may include a frame hosting one or more conversion modules, arranged as desired. A given conversion module may include one or more wind energy conversion devices (WECDs), arranged as desired. The conversion modules may be electrically connected, directly or indirectly, with one or more downstream electrical energy storage elements (e.g., such as a battery or other capacitive element, optionally native to a host platform). In this manner, the disclosed system may be configured for use in storing and/or supplying electric power for downstream consumption by a host platform or otherwise. In a more general sense, the disclosed system may be utilized, for example, for micro-generation of renewable electrical energy from wind.