Independent pitch control method for large wind turbine

Abstract

The invention provides an independent pitch control method for a large wind turbine, which comprises a coordinated pitch control process: detecting the rotation speed omega g of a motor, subtracting the reference rotation speed omega ref with the detected rotation speed omega g to obtain the rotation speed deviation delta omega; by the PI control, obtaining a coordinated pitch angle beta c expected to be output by the coordinated pitch control; the method also comprises a deviation pitch control process: 1) detecting the load (Mz1, Mz2 and Mz3) of the root part of a blade and an impeller azimuth signal psi, and making the Park conversion of the load (Mz1, Mz2 and Mz3) of the root part of the blade to obtain load components of Mtitl and Myaw; 2) obtaining the outputs of beta1 and beta2) by being controlled by the PI controller respectively; 3) by the PARK inverse conversion, obtaining the deviation pitch angles (beta1', beta2' and beta3') expected to be output by the deviation pitch control; and 4) obtaining the three blade expecting output pitch angles in the independent pitch control so as to control the action of the servo motor to realize the pitch control. The method can effectively avoid the appearance of the bigger fatigue loads.

Description

technical field [0001] The invention belongs to a control method of a large-scale wind turbine, in particular to a pitch control method. Background technique [0002] Factors such as wind shear, wind turbulence, tower shadow effect, and yaw deviation will produce unbalanced loads on the impellers of large wind turbines. Moreover, the larger the unit capacity of the wind turbine and the larger the diameter of the wind rotor, the stronger the unbalanced force on the entire wind rotor surface, and the more obvious the unbalanced load on the impeller. Unbalanced loads on the impeller can cause significant fatigue loads on important components such as pitch bearings, hubs, main shafts, yaw bearings, towers, etc. [0003] At present, almost all large-scale variable-speed and variable-pitch wind turbines adopt the cooperative pitch technology of independently driven blades, that is, three sets of independent pitch actuators get the same position command, but this way the unit cann...

AI Technical Summary

Problems solved by technology

[0008] In order to overcome the disadvantages that the existing pitch control methods of wind power generators cannot effectively reduce the unbalanced load on the impeller and are prone to large fatigue loads, the present invention provides a method to avoid large fatigue loads by measuring unbalanced loads. Independent pitch control method for large wind turbines under fatigue load

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