Low-voltage ride through method of winding type brushless double-fed wind power generator set

Abstract

The invention discloses a low-voltage ride through method of a winding type brushless double-fed wind power generator set. The low-voltage ride through method comprises the following steps of S1, calculating a voltage amplitude and a voltage drop depth of a power grid; S2, switching a control strategy of a power generator to a low-voltage ride through control strategy from a normal control strategy if the power grid drops; S3, detecting a current of a control winding of the brushless double-fed power generator in real time, calculating the size of reactive current which shall be injected to the power grid according to the voltage drop depth of the power grid if the current amplitude of the control winding is smaller than a threshold value of the rated current of the control winding, taking the reactive current as a current loop instruction of the control winding, and injecting the reactive current to the power grid to help recovery the voltage of the power grid by a machine-side current converter; S4, detecting the voltage of the power grid in real time, and judging whether a fault of the power grid is eliminated or not; and S5, switching the low-voltage ride through control strategy of the winding type brushless double-fed power generator to the normal control strategy. By the low-voltage ride through method, extra hardware is not additionally arranged, and the low-voltage ride through capability of the power generator can be improved.

Description

technical field [0001] The present invention relates to the technical field of low-voltage ride-through methods for wind power generating sets, in particular to a low-voltage ride-through method for a wire-wound brushless doubly-fed wind power generating set. Background technique [0002] Among the current grid-connected wind turbines, the brush doubly-fed wind turbines occupy a dominant position in the wind turbines above 1WM, but the brush doubly-fed wind turbines (DFIG) have the following three disadvantages: (1 ) has brushes and slip rings in structure, which reduces the reliability of the system. (2) The gearbox has a large volume, which increases the system cost. (3) The adaptability to grid voltage disturbance is very poor. The brushless doubly-fed wind generator (BDFG) can not only overcome and improve the above disadvantages of the brush doubly-fed wind generator, but also has the same advantages as the brush doubly-fed wind generator, which can realize variable s...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a low-voltage ride-through method for a wire-wound brushless doubly-fed wind power generator in view of the lack of a low-voltage ride-through method for a brushless doubly-fed wind power generator in the prior art

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