A pitch control method and system of a symmetrical-airfoil vertical axis wind turbine collects data by an anemometer, an anemoscope and an angle sensor, outputs an optimum pitch angle based on a control law of a pitch angle and controls the pitch angle to be the optimum pitch angle through a pitch control actuator. In addition to input variables of the control law such as a wind velocity v.sub.in and a blade azimuth angle Ψ, constants such as a rotation radius R, a rotation velocity Ω of the blade and aerodynamic coefficients c.sub.1, c.sub.2 and c.sub.3 are also related. A Reynolds number has little influence on three aerodynamic coefficients c.sub.1, c.sub.2 and c.sub.3. The pitch actuator controls the adjustment rods to realize the automatic pitch control of the blades. An expression of the control law of the pitch is concise, the calculation time is short, and a response speed is fast.

The present invention provides improved methods, apparatus, and manufacture for an Archimedes Screw using a new blade design to increase the volume of water raised or lowered by about 9%-18%. The invention, in part alters the shape of the blades within the screw from a helicoid shape to a new shape called a “makroid” by the inventor. A helicoid blade in an Archimedes Screw has been used since antiquity and has not changed since then, limiting the efficiency. The makroid shape allows a greater quantity of water to be contained within the screw.

The invention relates to a method for acquisition and modelling of an incident wind field by a LiDAR sensor. Acquisition and modelling include a step of estimating the wind amplitudes and directions for a set of discretized points, and a step of incident wind field reconstruction in three dimensions and in real time. The invention also relates to a method of controlling and/or monitoring a wind turbine equipped with such a LiDAR sensor from the incident wind field reconstructed in three dimensions and in real time.

A pitch control method and system of a symmetrical-airfoil vertical axis wind turbine is provided, which collects data by an anemometer, an anemoscope and an angle sensor, outputs an optimum pitch angle based on a control law of a pitch angle, and controls the pitch angle to be the optimum pitch angle through a pitch control actuator. In addition to input variables of the control law such as a wind velocity v.sub.in and a blade azimuth angle Ψ, constants such as a rotation radius R, a rotation velocity Ω of the blade and aerodynamic coefficients c.sub.1, c.sub.2 and c.sub.3 are also related. A Reynolds number has little influence on three aerodynamic coefficients c.sub.1, c.sub.2 and c.sub.3. The pitch actuator controls the adjustment rods to realize the automatic pitch control of the blades. An expression of the control law of the pitch is concise, the calculation time is short and a response speed is fast.

A method for controlling a wind power installation, wherein the wind power installation has a rotor with a plurality of rotor blades, the rotor blades are adjustable in their blade angle, each rotor blade is activatable individually, for the individual activation, in each case a total adjustment rate R.sub.of which indicates an intended speed of change of the respective blade angle is predetermined, a collective blade angle identical for all of the rotor blades is provided, a collective adjustment rate identical for all of the rotor blades describes an intended speed of change of the collective blade angle, an individual offset angle which indicates a value by which the blade angle is intended to deviate from the collective blade angle is predetermined for each rotor blade, an individual feed forward control adjustment rate which indicates an adjustment rate which is provided for reaching the offset angle is determined for each rotor blade from the individual offset angle, an individual offset deviation is determined for each rotor blade depending on a comparison of the individual offset angle and a detected blade angle of the rotor blade, and the total adjustment rate of each rotor blade is determined depending on the collective blade angle and/or the collective adjustment rate, the individual feed forward control adjustment rate, and the individual offset deviation.

The object of the invention relates to a method for acquisition and modelling of an incident wind field by a LiDAR sensor. Acquisition and modelling include a step of estimating the wind amplitudes and directions for a set of discretized points, and a step of incident wind field reconstruction in three dimensions and in real time. The invention also relates to a method of controlling and/or monitoring a wind turbine equipped with such a LiDAR sensor from the incident wind field reconstructed in three dimensions and in real time.

A method for controlling a wind power installation, wherein the wind power installation has a rotor with a plurality of rotor blades, the rotor blades are adjustable in their blade angle, each rotor blade is activatable individually, for the individual activation, in each case a total adjustment rate R.sub.of which indicates an intended speed of change of the respective blade angle is predetermined, a collective blade angle identical for all of the rotor blades is provided, a collective adjustment rate identical for all of the rotor blades describes an intended speed of change of the collective blade angle, an individual offset angle which indicates a value by which the blade angle is intended to deviate from the collective blade angle is predetermined for each rotor blade, an individual feed forward control adjustment rate which indicates an adjustment rate which is provided for reaching the offset angle is determined for each rotor blade from the individual offset angle, an individual offset deviation is determined for each rotor blade depending on a comparison of the individual offset angle and a detected blade angle of the rotor blade, and the total adjustment rate of each rotor blade is determined depending on the collective blade angle and/or the collective adjustment rate, the individual feed forward control adjustment rate, and the individual offset deviation.

A method of calibrating a yaw actuator of a wind turbine is provided, including steps of performing an active yaw operation in a clockwise yaw direction and an active yaw operation in a counter-clockwise yaw direction; recording data of a wind direction and a power caused by both yaw operations, and averaging the data and calculating an error between an experimental power difference and a theoretical power difference of yaw operations in the clockwise direction and a counter-clockwise direction; determining a minimum of the error; and determining a yaw misalignment based on the minimum error.