Research on adaptive control strategy of dynamic virtual inertia and damping coefficient for grid-forming direct-drive wind turbines

High-proportion wind power generation is connected to the grid through a large number of power electronic devices, which itself does not have the inherent inertial response characteristics as traditional synchronous generators, and virtual synchronous machine technology (VSG) provides a solution. In this paper, VSG control is introduced into the grid-side control unit of permanent magnet direct-drive wind turbine (D-PMSG), and its traditional control structure is changed. The stator voltage-oriented vector control strategy is combined with VSG control to build a D-PMSG-VSG system with active support for the grid. Then, the small signal model of D-PMSG-VSG active power is established to analyze the influence of inertia and damping coefficient on system stability. Finally, by analyzing the power frequency change in the transient process of the system and combining with the linear adaptive control, the virtual inertia and damping coefficient are dynamically adjusted in real time to reduce the power overshoot and frequency deviation.