A power optimization control method for variable speed and variable pitch wind turbines

Abstract

The invention relates to a power optimal control method for a variable-speed and variable-pitch wind turbine. The variable-speed and variable-pitch wind turbine is controlled within the whole designed wind speed range. When the wind turbine operates between the cut-in wind speed and rated wind speed, a variable-speed control mode is adopted, and at the time, by adjusting the electromagnetic torque of a generator, the wind turbine is made to operate under the optimal efficiency CP max. When the wind turbine operates above the rated wind speed, a variable-pitch controller begins to be used, and by adjusting the pitch angle, the maximum power output is limited at a rated value. At the time, a torque controller is a variable-gain controller, and different gains are set according to the rotation speed values corresponding to different wind conditions. The phenomenon that the wind turbine generates high power output within a short time when affected by gust and the like is greatly relieved. In addition, a switch rule is set for the variable-pitch controller near the rated wind, so that frequent switching of the variable-pitch controller near the rated wind is avoided. By means of the power optimal control method for the variable-speed and variable-pitch wind turbine, the service life of a gearbox is prolonged, and it is guaranteed that the wind turbine operates in a bad environment.

Description

technical field [0001] The invention belongs to the technical field of wind power generation, and in particular relates to a power optimization control method of a variable-speed variable-pitch wind turbine. Background technique [0002] In recent ten years, due to practical problems such as energy crisis and environmental pollution, people have gradually carried out the development and utilization of renewable energy. As a clean energy that widely exists on the earth, wind energy has developed rapidly in recent years. With the increase of installed capacity of wind power generation, the performance of the unit and the quality of power generation have attracted much attention, and higher requirements have been put forward for the control system and method of the wind power unit. [0003] At present, the control method of large-scale variable-pitch and variable-speed wind turbines mainly adopts the control method combining torque control and pitch control. Basically operate...

AI Technical Summary

Problems solved by technology

[0004] However, under the influence of extreme gusts, the wind turbine will generate a large power output in a short period of time. If the existing control system is used, the speed of pitch adjustment cannot keep up with the large delay characteristics of the pitch control system. The change of wind speed will cause the system to produce a large overshoot and shock, which will cause the overspeed phenomenon of the wind wheel, and will also cause the wind turbine to generate a huge load in a short period of time.

In addition, when the wind speed is constantly changing near the rated wind speed, the wind turbine will frequently switch between input and cut-out of the pitch controller, which will seriously affect the service life of the related components of the wind turbine

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