Load model establishment method and load control method of wind turbine

Abstract

The invention discloses a method for establishing a load model and a load control method of a wind turbine. First, iteratively obtains the axial induction factor and the circumferential induction factor corresponding to each group of blade tip speed ratio and pitch angle, and then calculates the wave coefficient and wind energy Coefficient, through several sets of flapping coefficients and wind energy coefficients corresponding to the tip speed ratio and pitch angle, nonlinear fitting to obtain the calculation formula of the flapping coefficient, wind energy coefficient with respect to the tip speed ratio and pitch angle, and obtain the load model; then in On the basis of the load model, the optimal pitch angle corresponding to the minimum flapping load when the output is constant at each wind speed is obtained, and the formula of the optimal pitch angle related to the wind speed is obtained by nonlinear fitting, which is calculated according to the wind speed when the wind turbine is running. The optimal pitch angle is obtained by obtaining the pitch angle adjustment value, which is superimposed with the pitch angle adjustment value obtained by the PID-based pitch control method to perform pitch angle control. The invention comprehensively considers the shimmy load and the flapping load, and realizes a more accurate load model and a load control method.

Description

technical field [0001] The invention belongs to the technical field of wind power, and more specifically, relates to a load model establishment method and a load control method of a wind turbine. Background technique [0002] With the increasingly severe energy and environmental problems, the research on renewable energy has attracted more and more researchers' attention. Among them, wind power technology has been widely used because of its small impact on the environment, no harmful gas, and relatively mature technology. However, with the maturity of wind power technology, the unit capacity of wind turbines continues to increase, and the size and weight of wind turbine mechanical components continue to increase, resulting in increasing flexibility of wind turbine mechanical components and a gradual decrease in the natural frequency of the system. Therefore, under the action of random, fluctuating and abrupt wind loads, the components of the unit may resonate, resulting in ...

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Problems solved by technology

At present, many researchers mainly adopt PID (Proportional-Integral-Differential, proportional-integral-differential) pitch control method based on PID (Proportional-Integral-Differential) to control the constant power above the rated wind speed. The load of wind turbines is reduced, but there is a lack of mathematical models for the loads on wind turbines

Most of the pitch-changing mechanisms use hydraulic actuators, which have a certain time delay. At the same time, the wind turbine is a strongly nonlinear system. The PID-based linear pitch controller has poor stability and cannot achieve good control effects.

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