Stator series impedance-based double-fed wind generation set high/low voltage ride through system and method

Abstract

The invention provides a stator series impedance-based double-fed wind generation set high / low voltage ride through system and method. The system comprises a DFIG stator loop connected with a power grid, wherein the DFIG stator loop comprises a filter inductor, a network side converter, a rotor side converter and a double-fed wind generation set, which are connected in sequence; a serial impedanceprotection circuit is arranged between the double-fed wind generation set and the filter inductor; the serial impedance protection circuit comprises a rapid switch and an impedance branch, which areconnected in parallel; the impedance branch comprises an impedance inductor and an impedance resistor, which are connected in series. According to the system and method, power grid comprehensive faultride through comprising high / low-voltage faults of DFIG is solved, complete compensation of DFIG stator voltage during faults is realized, the DFIG is enabled to satisfy rated working conditions, andtotal-power stator reactive support problem caused to power grids by DFIG during high / low-voltage faults is solved.

Description

technical field [0001] The invention relates to the field of operation of a doubly-fed wind power generation system under a faulty power grid, in particular to a high-low voltage ride-through method for a doubly-fed wind turbine based on stator series impedance. Background technique [0002] As the mainstream type of wind power generation, the doubly-fed induction wind turbine (DFIG) occupies a large proportion of the current installed wind power capacity due to its advantages of variable speed and constant frequency operation, small required converter capacity, and low cost. [0003] With the widespread manufacture and use of DFIG units equipped with crowbar circuits, most DFIGs have preliminarily met the requirements for non-off-grid operation under low-voltage faults in the power grid. When the power grid encounters a low-voltage fault, the crowbar circuit needs to be put into operation in time, and the rotor of the doubly-fed fan is short-circuited. From the perspective...

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Problems solved by technology

[0011] The above patents use additional energy storage modules, 3 sets of inverter bridges, and three-phase transformers to realize low-voltage ride-through of double-fed wind turbines, but these added auxiliary circuits are expensive and complicated to control and maintain

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