Load modelling method and load control method for wind turbine generator system

Abstract

The invention discloses a load modelling method and a load control method for a wind turbine generator system. The load modelling method and the load control method for the wind turbine generator system comprise the following steps: firstly, acquiring axial inducing factors and circumferential inducing factors corresponding to each group of tip speed ratios and pitch angles through iterating; secondly, calculating flapping coefficients and wind energy coefficients; thirdly, performing nonlinear fitting through the flapping coefficients and the wind energy coefficients corresponding to a plurality of groups of tip speed ratios and pitch angles to obtain a calculating formula of the flapping coefficients and the wind energy coefficients with respect to the tip speed ratios and the pitch angles, and obtaining a load model; fourthly, on the basis of the load model, calculating an optimal pitch angle corresponding to the least flapping load at each wind speed when the output is constant, and performing nonlinear fitting to obtain a formula of the optimal pitch angle with respect to the wind speed; fifthly, obtaining the optimal pitch angles according to the wind speeds when the wind turbine generator system operates through calculating, and obtaining pitch angle adjustment values; and finally, superposing the pitch angle adjustment values obtained on the basis of a PID (Proportion Integration Differentiation) variable pitch control method, and performing pitch angle control. According to the load modelling method and the load control method for the wind turbine generator system, shimmy load and flipping load are comprehensively taken into consideration, and a more accurate load model and a more accurate load control method are realized.

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 serious energy and environmental problems, the research of renewable energy has attracted more and more researchers' attention. Among them, wind power technology is widely used because of its low impact on the environment, no harmful gas generation, and relatively mature technology. However, with the increasing maturity of wind power technology, the single-machine capacity of wind turbines continues to increase, and the size and weight of wind turbine mechanical components continue to increase, resulting in the continuous increase of the flexibility of wind turbine mechanical components and the gradual decrease of the natural frequency of the system. Therefore, under the random, fluctuating and abrupt wind loads, the components of the ...

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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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