Wind generating set low voltage ride through circuit and corresponding control method

Abstract

The invention relates to a wind generating set low voltage ride through circuit and a corresponding control method. According to the invention, a rectifier bridge is additionally arranged at a generator rotor output line terminal of a wind generating set and positive and negative ends of a converter DC bus, and the rectifier bridge is connected to a converter bus in parallel. Meanwhile, a DBR circuit is connected to both ends of the converter DC bus in parallel. When the wind generating set is in a dropping process of grid voltage (u / ur>=20%), release of DBR resistance energy is realized through turn-on or turn-off of an IGBT (insulated gate bipolar transistor) in the DBR circuit, thereby maintaining dynamic balance of the converter DC bus dynamically, realizing current transformation of the wind generating set, and riding through a grid fault successfully; and in the dropping process of the grid voltage (u / ur<20%), the IGBT in the DBR circuit is turned off, a Crowbar in a Crowbar circuit is triggered to release energy accumulated on the rotor, thereby protecting the converter or the generator. The wind generating set low voltage ride through circuit and the corresponding control method can reduce or decrease various transient characteristics produced by the wind generating set in the whole dropping process of the grid voltage, improves harmful effects imposed on the wind generating set and a power grid by the various transient characteristics, improves the performance of the wind generating set and prolongs the service life of the wind generating set.

Description

technical field [0001] The invention relates to a low-voltage ride-through circuit of a wind power generating set and a corresponding control method, belonging to the technical field of wind power generation. Background technique [0002] With the large-scale grid-connected power generation of wind turbines at home and abroad, when the grid voltage of wind farms drops or is disturbed for a short time, it may cause large-scale wind turbines to go off-grid, directly cause equipment damage, and even cause the grid to collapse. Therefore, the wind turbines operating in the wind farm must have a certain low-voltage ride-through capability to ensure that the wind turbines ride through the fault when the above-mentioned grid fault occurs, and ensure the safety of the turbine and the grid. The research on low-voltage ride-through technology of wind turbines has become one of the research hotspots of scholars at home and abroad. The most common low-voltage ride-through technology sch...

AI Technical Summary

Problems solved by technology

The research on low-voltage ride-through technology of wind turbines has become one of the research hotspots of scholars at home and abroad. The most common low-voltage ride-through technology scheme adopts active or passive Crowbar circuit-related technologies. The general low-voltage ride-through circuit includes the wind turbine and the power grid. The converter, the grid-side converter, and the crowbar circuit installed on the rotor side of the wind turbine realize low-voltage ride-through through the crowbar circuit. All will produce various transient characteristics (such as current generation, electromagnetic torque, torque transient jump, etc.) These transient characteristics have adverse effects on grid stability, wind turbine characteristics and service life

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