用于逆变器分布式控制的切换式环网通信与同步方法

Switchable Fiber Ring Net and Synchronization Method for Inverter Distributed Control

针对并联运行三相逆变器模块分布式控制问题,提出采用高速切换式光纤环网搭建分布式控制网络,每一个逆变器模块作为环网中的一个节点。结合具体的环网通信协议,计算切换式光纤环网一个开关周期内完成数据通信的时间,得出切换式光纤环网的应用范围。为了实现并联运行逆变器模块电流均衡并避免产生环流,采用环网中各节点精确同步的控制策略,使各个子节点产生相同的开关驱动脉冲。提出3种应用于切换式环网的节点同步方法,通过分析3种同步方法的时间延迟和同步精度,得出适合并联运行三相逆变器模块的双光纤环网拓扑结构。该结构简单可靠、同步精度高。搭建了切换式光纤环网实验平台,验证了切换式光纤环网通信时间计算方法和节点同步方法分析的正确性。

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.