A reactive power control method for doubly-fed wind turbine generator grid voltage imbalance surge

Abstract

The invention discloses a method for reactive power control of voltage unbalance sudden rise of a double-feed wind generator set power network. The method is characterized by comprising the following steps: 1, decoupling positive and negative sequences of the voltage of a stator of a double-feed motor; 2, calculating the reactive current of the stator; 3, calculating the proportion of positive sequence reactive power in total reactive power; 4, calculating and synthesizing a current instruction value of a rotor; and 5, performing closed-loop control on the current of the rotor. By adopting the method disclosed by the invention, the distribution of the stator current and positive and negative sequence reactive power can be controlled, thereby achieving a target of performing compound control on the degree of asymmetry of generator terminal voltage and reactive power ripple rejection.

Description

technical field [0001] The invention belongs to the field of wind power generation, and specifically relates to a reactive power control method for a doubly-fed wind power generating set grid voltage unbalanced sudden rise. Background technique [0002] Doubly-fed wind turbines are currently the mainstream type of megawatt-scale variable-speed constant-frequency wind turbines. The reactive power pulsation under the condition of grid voltage surge is one of the main goals of current doubly-fed unit research. In order to comply with the power grid guidelines, wind turbines must have certain high voltage ride-through capabilities, such as the high voltage ride through guidelines proposed by Australia. When the voltage of the high-voltage side grid suddenly rises to 130% of the rated voltage, the wind turbines should not be disconnected from the grid for 60ms , and during the grid voltage surge, the reactive power will produce a large pulsation, if it is not controlled, it will ...

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Problems solved by technology

However, the amount of reactive power pulsation under asymmetric grid voltage swell is different from that under symmetrical swell, which leads to the fact that the reactive power control strategy under symmetric grid voltage swell cannot effectively suppress the power pulsation under asymmetric grid voltage swell.

[0005] The relevant literature on doubly-fed generator control for asymmetric grid voltage surge is also limited to Xie Zhen, Zhang Xing, Yang Shuying, etc. Improved control strategy of doubly-fed wind turbine generator under asymmetric grid voltage surge[J]. China Electrical Engineering Journal of the Chinese Academy of Sciences, 2013, 33(15): 109-118. However, it does not consider the control strategy of doubly-fed wind turbines under reactive power

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