High and low voltage ride through system and method for double-fed wind turbine based on stator string impedance

Abstract

The present invention provides a doubly-fed wind turbine high and low voltage ride-through system and method based on stator series impedance, which includes a DFIG stator loop connected to the power grid, and the DFIG stator loop includes a filter inductor connected in sequence, a network measuring converter, and a rotor side A converter and a doubly-fed wind generator, a series impedance protection circuit is connected in series between the doubly-fed wind motor and the filter inductance, the series impedance protection circuit includes fast switches connected in parallel and an impedance branch, the impedance branch includes Impedance inductor and impedance resistor connected in series. The invention solves the power grid comprehensive fault ride-through of DFIG including high and low voltage faults, realizes the complete compensation of DFIG stator voltage during the fault period, makes DFIG meet the rated working conditions, and solves the problem of DFIG on the full power stator of the power grid during high and low voltage faults Reactive support problem.

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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