Voltage frequency cooperative control method of double-feed asynchronous wind turbine generator in micro grid

Abstract

The invention relates to a voltage frequency cooperative control method of a double-feed asynchronous wind turbine generator in a micro grid. A frequency control module is controlled through a rotor converter, when the frequency is changed in the micro grid, a virtual inertia link in the frequency control module can quickly respond to an f-P droop control link, and the system frequency is stabilized to a new stabilizing point. By adding an accessary DFD logic module in an existing rotor converter for voltage control, the capability for the double-feed synchronous wind turbine generator to provide voltage frequency support in the micro grid is improved. The method can makes a DFIG automatically inhibit micro grid voltage fluctuation brought by power change of the DFIG, when the droop control causes that the micro grid voltage exceeds a limit, reactive power output of the DFIG can be further increased, and voltage deviance of the micro grid is lowered; meanwhile, the voltage frequency control module guarantees power distribution of the DFIG and other distributed power sources in the micro grid, peer-to-peer control of the micro grid can be achieved, and the voltage frequency stability of the micro grid is improved.

Description

technical field [0001] The invention relates to a micro-grid control technology, in particular to a voltage-frequency coordinated control method of a doubly-fed asynchronous wind turbine in a micro-grid based on droop control. Background technique [0002] Doubly-fed asynchronous (DFIG) wind turbines are widely used in existing wind power generation because of their characteristics of variable speed, constant frequency and PQ decoupling control. Among them, the virtual inertia control of DFIG has been studied by many experts. DFIG introduces the frequency control link in the wind turbine, and when the frequency of the microgrid changes suddenly, it releases the kinetic energy of the DFIG rotor to increase the active output to participate in frequency regulation. At the same time, through the load shedding control, the DFIG is in the secondary MPPT operating state when it is working normally, and a certain amount of power is reserved to participate in the primary adjustment o...

AI Technical Summary

Problems solved by technology

[0010] The present invention aims at the problems existing in the control of doubly-fed asynchronous wind turbines in micro-grids, and proposes a voltage-frequency coordinated control method for doubly-fed asynchronous wind turbines in micro-grids, which overcomes the only frequency control of existing doubly-fed asynchronous wind turbines The method ignores the voltage support ability of its own reactive output to the microgrid, and does not consider the voltage fluctuation of the microgrid caused by the change of the active output of the wind turbine. , give full play to its voltage and frequency support ability, so that the microgrid can further improve the frequency and voltage stability, by adding the improved voltage control to the existing rotor converter control, through the additional DFD (voltage logic comprehensive discrimination) Module, which improves the ability of double-fed wind turbines to provide voltage and frequency support in microgrids

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