A digitally based HVDC firing-pulse synchronization control - description and model development

Modern dc converter firing control systems utilize phase locked loop techniques to synchronize valve firing-pulses with the ac voltage. Moreover, these systems are becoming digitally based with computers used to control the process. An EPRI research project has provided insight to the behavior of these important control functions. This paper describes a digitally based firing-pulse synchronizing control system, examines some basic dynamic performance issues, and describes a model suitable for small-signal stability analysis of this discrete-time process.