Switchable fiber ring net and synchronization method for inverter distributed control

Solution of adopting the switchable fiber ring net to implement the distributed control of two parallel operating three phase inverters is proposed, with each inverter module as a slave node in the fiber ring net. According to the protocol, the communication time in one switching cycle is calculated and the application range that can use the switchable fiber ring net is obtained. To implement equal current sharing between parallel operating three phase inverters and avoid the circulating path, precise synchronization strategy is used in the switchable fiber ring net and every slave node generates the same drive signal. Three synchronization methods for the switchable fiber ring net are proposed. With time delay and synchronization accuracy compared between the three methods, a dual fiber ring net suitable for two parallel operating three phase inverters is obtained, which is simple, reliable and accurate. An experimental bed for testing the switchable fiber ring net and its synchronization methods is built. The correctness of analysis of the communication time calculation and synchronization method is verified.