Variable-speed variable-frequency wind turbine primary frequency modulation method and device

Abstract

The invention provides a variable-speed variable-frequency wind turbine primary frequency modulation method and device. The primary frequency modulation method comprises the following steps: A) detecting current frequency of a power grid; B) calculating frequency deviation between the current frequency of the power grid and standard frequency, and determining whether the frequency deviation is beyond a frequency dead zone; C) when the frequency deviation is beyond the frequency dead zone, determining first power of a wind turbine; and D) when the frequency deviation is beyond the frequency dead zone, adjusting a torque given value of the wind turbine and controlling pitch angle of the wind turbine to enable the wind turbine to output the first power to realize primary frequency modulation.In the wind turbine primary frequency modulation method, the primary frequency modulation of the grid system is carried out through torque and variable pitch coordination control, so that the methodhas faster inertia response speed, meanwhile, effectively prevents the problem of over speed of rotating speed of a rotor of the wind turbine, and can realize fast and accurate change of output powerof the wind turbine under stable operation of the wind turbine.

Description

technical field [0001] The present invention relates to the technical field of control of wind power generation systems, and more specifically, to a method and device for primary frequency regulation of variable-speed and variable-frequency wind turbines. Background technique [0002] Power system operation is a process of real-time balance between power generation and load. When the system frequency changes greatly due to machine cut-off or sudden load change, the rotor speed of conventional synchronous generators will automatically change accordingly due to the coupling relationship between the speed and system frequency. By releasing / absorbing the kinetic energy of the rotor The frequency of the damping system changes rapidly, and then the system frequency tends to be stable through a frequency adjustment. However, the variable-speed constant-frequency wind turbines that are currently most widely used, although back-to-back (back-to-back) converters are used to achieve v...

AI Technical Summary

Problems solved by technology

However, this method is greatly affected by the randomness of wind speed and will reduce the power generation efficiency of wind farms.

Pitch control reserves part of the reserve capacity by controlling the pitch angle of the fan. This method has a slower response speed and increases the fatigue of the pitch system and reduces the operating life of the unit.

[0004] To sum up, the current variable speed and variable frequency wind turbines lack effective primary frequency modulation control technology

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