A joint control method of variable pitch and variable torque for variable speed wind turbines

Abstract

The invention discloses a pitch change and torque change combined control method of a variable-speed wind turbine generator system. Unmodeled dynamics and disturbance are considered to build a simplified dynamic model of the wind turbine generator system. Power adjustment error dynamic characteristics are calculated. A sliding mode surface and switching functions are selected to design a self-adaption updating mechanism of sliding mode gaining to obtain sliding mode variable structure electromagnetic torque control signals. Wind wheel rotating speed anticipant error dynamic characteristics aredefined. The simplified dynamic model of the wind turbine generator system is rewritten to obtain a pitch angle initial expression. Approach results of a low-pass filter to non-affine uncertain itemsand disturbance items are substituted into the pitch angle initial expression to obtain a pitch angle final expression. The combined control method can preferably deal with non-affine uncertain characteristics of the wind turbine generator system, is simple in structure and excellent in robustness, can provide more stable wind wheel rotating speed and power generation power, reduces mechanical load of the wind turbine generator system, prolongs the service life, and provides high-quality electric energy to a power grid.

Description

technical field [0001] The invention relates to the technical field of control of wind power generators, in particular to pitch and torque control in the high wind speed section of variable speed wind power generators. Background technique [0002] With the increasing shortage of world energy and the rapid development of science and technology, coupled with people's requirements for environmental protection, the development of renewable green energy has become very urgent. The outstanding advantages of wind power generation are good environmental benefits and no problem of resource depletion. In recent years, they have developed rapidly all over the world. In order to maintain the rapid development of wind power generation, the grid-connected performance of wind turbines should be continuously improved. [0003] Currently, most wind farms use variable speed wind turbines. Compared with constant-speed wind turbines, variable-speed wind turbines have the advantages of good s...

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Problems solved by technology

[0007] In order to solve the problem that the existing pitch angle controller does not consider the dynamics of the system without modeling and environmental interference, and the output power fluctuates greatly, the present invention provides a joint control of variable pitch and torque with stable output power and good robustness in the high wind speed segment method, that is, the power is adjusted by the electromagnetic torque, and the speed of the wind rotor is adjusted by the pitch angle, which can better deal with the non-affine uncertain characteristics and external disturbances of the wind turbine. The invention can provide more stable power output for wind power grid connection

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