Stability analysis of a digitally based HVDC firing-pulse synchronization control

This paper presents a step-by-step analysis of the performance and stability characteristics of a digitally based dc firing-pulse synchronizing control. The performance of the loop is dependent upon parameters of the ac system, dc system, and the primary dc regulators. The synchronizing loop at the inverter tends to destabilize low frequency modes of the overall system. Control loop filtering is an effective means of stabilizing this interaction.