PLL-based Clock Recovery Stability Analysis for Distributed Power Electronics Communication Networks with Sub-nanosecond Synchronization Accuracy

Modular power converters in combination with distributed control architecture has been promising in medium-voltage applications due to its modularity and scalability. The requirement of the synchronization accuracy is elevated dramatically for the communication network with advanced distributed control schemes. This paper presents a phase-locked loop (PLL)-based synchronization method with sub-ns synchronization accuracy based on the White Rabbit protocol. Digital perturbation injection method is proposed to estimate the PLL closed-loop characteristics, and the PLL stability is analyzed. Good agreements of the closed-loop transfer function and stability analysis have been achieved between the theoretical calculation and experimental results. A four-PEBB 6kV SiC-based converter is established to verify the distributed communication and control system.