Direct-driven wind turbine generator subsynchronous oscillation suppression method capable of capturing frequency points in self-adaptive mode

Abstract

A direct-driven wind turbine generator subsynchronous oscillation suppression method capable of capturing frequency points in a self-adaptive mode comprises the steps of: firstly, designing a subsynchronous oscillation additional control loop; then, adopting real-time FFT analysis to track oscillation frequency points at the grid-connected part of the fan; performing self-adaptive adjustment of anadditional control loop based on the tracking frequency points; and finally, improving the phase-locked loop control strategy of the direct-driven wind turbine generator by applying the designed additional control loop of the self-adaptive capture frequency point, wherein compared with a current inner loop additional damping or the same type of subsynchronous oscillation suppression scheme, the direct-driven wind turbine generator subsynchronous oscillation suppression method can accurately and effectively suppress the subsynchronous oscillation of the direct-driven wind turbine generator, the suppression effect weakening and overshoot possibly caused by oscillation frequency point offset in an existing method are avoided, and the method has important practical significance for safe and stable operation of a direct-drive wind turbine generator access system.

Description

Technical field[0001]The invention belongs to the technical field of electric power systems, relates to the stability control technology of a direct-drive wind turbine grid-connected system, and in particular relates to a direct-drive wind turbine subsynchronous oscillation suppression method that adaptively captures frequency points.Background technique[0002]The gradual increase in the proportion of new energy electric energy connected to the system has brought new challenges to the safe and stable operation of the power system, including stability issues such as subsynchronous oscillations. At present, direct-drive wind turbines have been widely used in the field of new energy power generation. Under the premise that the back-to-back dual PWM converters isolate the machine and the grid, the direct-drive wind turbine still has sub-synchronous oscillation after it is connected to the system. Regardless of the generation mechanism and the manifestation, the direct-drive wind turbine ...

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Problems solved by technology

However, this solution does not improve the root cause of the subsynchronous oscillation of the direct drive fan, that is, the measurement deviation of the phase-locked loop, so the effect of suppressing the subsynchronous oscillation is quite limited

In addition, since the subsynchronous oscillation frequency will change with the change of wind speed, network parameters, etc., at this time, the traditional subsynchronous oscillation control scheme weakens the subsynchronous oscillation suppression ability due to the difficulty in obtaining dynamic oscillation information, and even the frequency point The overshoot state occurs due to the offset, and a new oscillation problem is caused

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