Subsynchronous oscillation suppression method for direct-drive permanent magnet synchronous wind turbine generator in weak power grid

The invention relates to a wind power control technology, in particular to a method for suppressing secondary synchronous oscillation of a direct-drive permanent magnet synchronous wind turbine generator in a weak power grid. The invention provides an additional damping oscillation suppression method based on uncertainty and a disturbance estimator UDE for solving the problems of power generation system instability and power distribution network voltage fluctuation caused by next synchronous oscillation of a weak power grid of a direct-drive permanent magnet synchronous wind turbine generator. Firstly, a grid-side converter adopts a virtual synchronous machine (VSG) technology, and a grid-side converter sequence impedance model is established based on a harmonic linearization theory; secondly, a UDE-based additional damping robust control method of a current loop is provided. According to the UDE-based additional damping controller, disturbance of factors such as power grid voltage and active instructions is