A method and system for determining fundamental frequency negative sequence impedance of a doubly-fed induction generator system

Abstract

The invention relates to a method and system for determining fundamental frequency negative sequence impedance of a double-fed induction generator system. The method includes: the relationship between the GSC output current, voltage and grid-connected point voltage in the abc static coordinate system, the relationship between the RSC current, voltage and flux linkage of the rotor-side converter of the unit; The current in the RSC and the current in the RSC are converted to the frequency domain; determine the GSC coordinate transformation matrix and the RSC coordinate transformation matrix and determine the dq component of the voltage command value output by the GSC and the dq component of the voltage command value output by the RSC; determine the GSC and RSC in abc A-phase output voltage command value in the coordinate system; and determine the GSC DC steady state characterization quantity and RSC DC steady state characterization quantity, and determine the fundamental frequency negative sequence impedance model of GSC and the fundamental frequency negative sequence impedance model of RSC; according to the two models Determine the negative sequence impedance model of a doubly-fed induction generator system. The invention can accurately determine the fundamental frequency negative sequence impedance of the double-fed induction generator system.

Description

technical field [0001] The invention relates to the technical field of wind power generation, in particular to a method and system for determining the fundamental frequency negative sequence impedance of a doubly-fed induction generator system. Background technique [0002] The centralized access of large-scale wind power to the power grid is affected by the time-varying characteristics of the negative sequence impedance of new energy units, and it is prone to three-phase voltage imbalance. Asymmetry, the relevant mechanism is rarely studied from the perspective of the negative sequence impedance of the doubly-fed induction generator system (double-fed induction generator) itself, and the existing fundamental frequency negative-sequence impedance model of the doubly-fed induction generator system cannot be directly reflected. The influence of the parameters of the fan itself, phase-locked loop, current regulator and other links on the fundamental frequency negative sequence ...

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Problems solved by technology

[0002] Large-scale wind power centralized access to the grid is affected by the time-varying characteristics of the negative sequence impedance of new energy units, and it is prone to voltage three-phase imbalance. asymmetry, and the relevant mechanism is rarely studied from the perspective of the negative sequence impedance of the doubly-fed induction generator system (doubly-fed fan), and the existing fundamental-frequency negative-sequence impedance model of the doubly-fed induction generator system cannot intuitively reflect The influence of the parameters of the fan itself and the phase-locked loop, current regulator and other links on the negative sequence impedance of the fundamental frequency

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