Flux-tracking low voltage ride-through method under asymmetrical voltage faults of brushless doubly-fed wind generator

Abstract

The invention relates to a flux-tracking low voltage ride-through method under asymmetrical voltage faults of a brushless doubly-fed wind generator. The method is a flux-tracking-control low voltage ride-through method under three asymmetrical voltage faults, which include phase-to-phase short circuit, phase-to-phase earthing short circuit and single-phase earthing short circuit of the grid connection points of the brushless doubly-fed wind generator. The method has the advantages that a PI-R controller is used as the flux vector amplitude tracking controller of the control windings of the brushless doubly-fed wind generator, a control device and system of the flux-tracking low voltage ride-through operation state under the asymmetrical voltage faults of the brushless doubly-fed wind generator are built, the cage type rotor brushless doubly-fed wind generator can use a software control method to achieve asymmetrical voltage ride through, and the method is low in low-voltage ride through torque ripple, capable of reducing unit transmission chain pressure, simple in system structure and lo in cost; reactive currents can be injected into a power grid to support power grid voltage under the single-phase earthing short circuit fault under a certain condition.

Description

technical field [0001] The present invention is related to the low-voltage ride-through method of the brushless doubly-fed wind power generator in the case of a voltage failure at the grid-connected point. A low-voltage ride-through control method of flux tracking control that can be realized by software in the αβ stationary coordinate system under three asymmetrical fault conditions such as single phase-to-ground short circuit. Background technique [0002] The energy problem has become a prominent problem in the development of today's society, and wind power generation is an important means to solve the current prominent problem, and it is also the fastest growing energy source in the world. Wind turbines are often located in remote areas such as high mountains, wilderness, and islands where there are relatively few human activities. They are also affected by irregular winds and strong gusts, and the natural environment where transportation is inconvenient. Once a fault oc...

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Problems solved by technology

[0008] Aiming at the problems of complex structure of the control system and large torque ripple during the operation of low voltage ride through in the low voltage ride through control under the condition of asymmetrical voltage fault using the software method of the existing brushless doubly-fed wind power generator, the present invention proposes a A Brushless Doubly-fed Wind Turbine Generator Asymmetric Voltage Fault Flux Linkage Tracking Low Voltage Ride Through Method

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