A grid-connected doubly-fed induction generator stator current control method and device

Abstract

The invention provides a method and device for controlling the stator current of a grid-connected doubly-fed induction generator. The method includes: performing coordinate transformation on the collected parameters of the doubly-fed induction generator to obtain The stator voltage vector U sαβ and the stator current vector I sαβ ; Calculate the stator current vector I of the doubly-fed induction generator sαβ α, β axis command; according to the DFIG stator current α, β axis command and the actual measured feedback value, calculate the rotor voltage command U' under the stator two-phase stationary coordinate system rαβ ;To the rotor voltage command U' rαβ Carry out coordinate transformation to obtain the rotor voltage command U in the rotor two-phase static α-β coordinate system rαβ ;According to the rotor voltage command U rαβ A set of PWM signals are obtained to control the rotor converter of the doubly-fed induction generator. The technical scheme provided by the invention simplifies the design and implementation process of the control system, and enhances the adaptability of the control system to generator parameter changes.

Description

technical field [0001] The invention relates to a doubly-fed induction wind power generator control method and device, in particular to a grid-connected doubly-fed induction generator stator current control method and device. Background technique [0002] Due to the advantages of small converter capacity and variable speed and constant frequency operation of DFIG, DFIG has become the mainstream type of wind turbine, accounting for 70-80% of the installed capacity, and is also the current wind power technology field. The main research object, especially the research on the operation and control of doubly-fed induction generator. [0003] The control of double-fed induction generator is mainly divided into two categories: vector control and direct power control. In vector control, the stator voltage phase angle (or stator flux phase angle) is obtained as the coordinate transformation angle of the synchronous rotating coordinate system through a phase-locked loop, and then a p...

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Problems solved by technology

However, the switching frequency of the converter using direct power control is uncertain, which will lead to the injection of broadband harmonic current into the live grid, making it difficult to design filter inductors

In addition, direct power control lacks the necessary current closed-loop link, which will lead to the actual situation that its output current quality is not up to standard. However, IEEE, IEC and my country's power quality related standards have put forward corresponding quantitative indicators for grid-connected current

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