Low-Frequency Oscillation Suppression Strategy for Grid-Forming PMSG-Based Wind Turbines Using Novel Exponential Sliding-Mode Control

With the increasing integration of wind power into the grid, power systems are exhibiting characteristics of low inertia and low short-circuit ratio. Virtual synchronous generator (VSG) control technology, which emulates the operational characteristics of synchronous generators, can effectively provide voltage and inertia support to the grid. However, its application in grid-connected permanent magnet synchronous generator (PMSG)-based wind turbines is prone to low-frequency oscillation issues. To address this, this paper first establishes a damping torque model for the grid-forming PMSG. The damping torque method is employed to quantify the damping characteristics of the system in the low-frequency band, while analyzing the influence of various torque components on the system’s damping composition and low-frequency oscillations. Based on this, a machine-side current loop controller incorporating a novel exponential sliding-mode control (NESMC) and a high gain disturbance observer (HGDO) is proposed. This controller aims to reduce the machine-side negative damping effect, thereby effectively suppressing low-frequency oscillations in the system. Finally, a simulation model is built in MATLAB/Simulink to verify the correctness of the damping torque analysis and the effectiveness of the proposed control method.