Subsynchronous Oscillation Mitigation Strategy Based on First-Order LADRC for Direct-Drive Wind Turbines

Aiming at solving the problem of subsynchronous oscillations (SSOs) induced by direct-drive wind turbines connected to the weak AC power grid, this paper proposes a first-order linear active disturbance rejection control (LADRC) strategy to suppress this phenomenon, thereby improving system stability. Firstly, the grid-connected mathematical model of direct-drive wind turbines is built, and the propagation mechanism of frequency disturbance components of SSOs is analyzed. On this basis, we design the first-order LADRC inner-loop current controller and optimize and tune the parameters, and the analysis indicates that the controller has a strong inhibitory effect on the frequency disturbance components of SSOs. Finally, using PSCAD/EMTDC simulation software, we build an electromagnetic transient simulation model of direct-drive wind turbines controlled by traditional PI and first-order LADRC. The results demonstrate that the proposed method can block the frequency disturbance components of SSOs and effectively suppress SSOs.