An important development trend toward power electronic technology was the integration and modularization. A key concept was Power Electronic Building Blocks (PEBB). Converters which were PEBB-based had lots of advantages, such as cost reduced, easy to reconfigure, reliability enhanced and so on. PEBB-based converters wound operation with distributed digital control, and a cascaded ring topology was the dominant solution for communication network. The characteristics of the ring topology determined the synchronization mechanism was a key technology. This paper addressed two synchronization mechanisms for ring topology network, and analyzed the factors which impact the synchronization precision. At last, aimed at the practice application, this paper compared their strongpoint with each other.