Impact of DC-Bus Voltage Control on Synchronization Stability of Grid-Tied Inverters

The impact of dc-bus voltage control (DVC) on transient synchronization stability of grid-tied inverters operating in grid-feeding mode has been assessed in this brief. A nonlinear quasi-static model magnifying the dynamics of phase-locked loop (PLL) and DVC of grid-tied inverter has been developed first. Following this, the steady-state and transient stability boundaries of the model are analytically characterized and numerically evaluated. The proposed model and the stability assessment method eliminates the inaccuracies associated with the previously developed model which considers the dynamics of PLL alone.