Doubly fed wind power generator control structure under asymmetric sudden rise of power grid voltage

Abstract

The invention discloses a doubly fed wind power generator control structure under asymmetric sudden rise of power grid voltage. In doubly fed wind power generator rotor excitation control, an active damping coefficient R1 is introduced into a rotor negative sequence current inner loop, the product of the active damping coefficient R1 and a negative sequence feedback current of d-q axis of a rotor is added onto output of a rotor negative sequence current d-q axis regulator so as to form an active damping control structure of the rotor side negative sequence current inner loop, an active damping coefficient R2 is introduced into a stator negative sequence current outer loop, and the product of the active damping coefficient R2 and a d-q axis negative sequence feedback current of a stator is added onto output of a stator negative sequence current d-q axis regulator so as to form a rotor converter double synchronous rotating reference frame improvement control strategy based on active damping. The doubly fed wind power generator control structure can effectively suppress oscillation of rotor negative sequence currents and electromagnetic torque, and a transient process of suppressing a stator negative sequence current when the power grid voltage suddenly rises asymmetrically is accelerated, and furthermore ability of system dynamics responses is improved.

Description

technical field [0001] The invention relates to the field of wind power generation, in particular to a doubly-fed wind power generator control structure under asymmetric sudden rise in grid voltage. Background technique [0002] When the grid voltage rises asymmetrically, its transient process will also form a strong current and voltage impact on the stator and rotor of the doubly-fed generator, which will affect the normal operation of the generator, such as increased loss, increased heat, Torque pulsation and the fatigue loss of the gearbox and mechanical transmission shaft, reactive power pulsation, etc. caused by torque pulsation, if no corresponding control measures are taken, these asymmetric effects will further deteriorate the grid voltage. The State Grid Corporation has issued a wind power The technical regulations for grid connection of wind farms clearly require that when the negative-sequence voltage imbalance at the grid-connected point of the wind farm reaches ...

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Problems solved by technology

In the power system, in addition to steady-state asymmetric faults, there are also transient asymmetric faults, which will cause more serious unbalanced grid voltage, resulting in over-current of the converter or excessive DC bus voltage, which is harmful to the converter. device security poses a great threat

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