High-Frequency Impedance Shaping for Virtual Admittance-Based Grid-Forming STATCOM

Grid-forming static synchronous compensator is an effective solution for inverter-based resources for reactive power support at the point of common coupling. However, the alternating voltage controller design is not fully investigated, and the potential high-frequency resonance may be triggered due to the control delay and the grid capacitive compensation. This paper mainly focuses on the virtual admittance-based voltage control, and the dissipative region of the converter output impedance in the high-frequency range is first discussed. Afterward, a passivity-based damping method is proposed using capacitor current feedforward and capacitor voltage feedforward, and the dissipative region can be optimized to the Nyquist frequency. Finally, the effectiveness of the proposed method is validated through the case study.