A switchable high-speed fiber-optic ring net topology and its method of high-performance synchronization for large-capacity power electronics system

•We introduce the principle of the distributed system for power electronics system.•We make a simple and feasible communication protocol.•We present a high-performance synchronization method based on the sequence observer.•We fulfill the synchronization accuracy within 8 ns of the whole system.•Results verify the correctness and feasibility to the proposed protocol and method.

With the particularity in the structures of large-capacity power electronics converter devices, the high-speed serial fiber-optic ring net communication control mode has gradually superseded the conventional centralized control mode. However, this fiber-optic ring net cannot accurately synchronize all the nodes in the system easily due to its own network delay and data retransmission, and even the net requires a more complex communication protocol for its operation. To solve these problems, this paper has conducted an investigation into the proposed switchable high-speed fiber-optic ring net, made a simple and feasible communication protocol and presented a method of high-performance synchronization based on the sequence observer. The synchronization method can be used to achieve the synchronization accuracy within 8 ns, thus overcoming the low accuracy and the accumulation of delay errors that exist in the current synchronization methods. As a result, the accurate synchronization of the whole system has been fulfilled. Finally, The results obtained from the data communication and synchronization performance experiments and the system’s trial run have verified the correctness, feasibility and superiority both the developed communication protocol and the proposed synchronization method.