The high speed ring network is one of the key methods for power electronic systems to achieve modularization and standardization. The conventional communication strategy of retransmit ring network takes a very long time. The time taken by switchable ring network is relatively short

but it will introduce error data in the serial codes. To solve this problem

this paper proposes an communication strategy of auto-retransmit ring network for distributed control of the power electronic system. Most of the command retransmit process is omitted in this strategy. The time taken in one sampling period is decreased a lot and the ring network performance is increased a lot. The time models of conventional and auto-retransmit ring network strategies are both analyzed. The communication time in one sampling period is calculated for both strategies. The experiment results have verified the effectiveness and reliability of the proposed auto-retransmit ring network strategy. This work is supported by National Basic Research Program of China(973 Program)(No. 2015CB251004)and National Natural Science Foundation of China(No. 51477180).