Subsynchronous Oscillation Suppression of Grid-Forming Converter Connected to Low-Impedance Grid

This paper investigates the subsynchronous oscillation suppression of grid-forming (GFM) converter connected to low-impedance grid with frequency-compensated active damping control scheme. To begin with, a small-signal model of GFM converter is built, and the subsynchronous oscillations caused by GFM converter connected to low-impedance grid is analyzed based on the eigenvalue locus and damping ratio of the system. On the basis, the frequency-compensated active damping control scheme is proposed to suppress the subsynchronous oscillations of GFM converter with changing the control structure of the power loop. Furthermore, the effect and mechanism of frequency-compensated control scheme on stability of systme is analyzed by the complex torque coefficient approach. Finally, the model of GFM converter is constructed on the Matlab/Simulink platform to verify the effectiveness of the proposed scheme.