一种改进的分布式逆变器并联控制策略

逆变器的冗余并联控制技术是实现交流供电系统高可靠性的关键。逆变器并联的控制方法有很多种，主从法必须依赖主模块工作，没有实现真正的冗余控制；频率电压外特性下垂法存在输出外特性较差等不足。基于平均电流控制的分布式并联控制策略易于实现逆变器的冗余及热插拔，但其存在输出外特性软的缺点，该文在该控制策略的基础上加上了负载电流前馈控制技术，以提高输出外特性，同时保留了原控制方案的输出限流功能和均流效果不变。论文分析比较了加负载电流前馈技术前后的输出外特性及环流特性，并研制了一台样机，进行了实验验证。

An Improved Distributed Control Strategy of Parallel Inverters

The redundant control technique for parallel inverters is crucial to the improvement of reliability of ac power supply systems. There are several control strategies suitable for the parallel operation of inverters, such as master-slave method and frequency and voltage droop technique. The former one can not virtually realize the redundancy because the slave module is dependent on the master module. The disadvantage of the latter one is that it often results in poor output characteristic. A distributed control strategy based on average current control is suitable for the redundancy and hot swap of inverters. However, the strategy has the defect of poor output characteristic. In order to improve the output characteristic, the load current feed-forward control is employed in this paper. The improved control strategy maintains previous current-limiting function and the effect of current sharing is unchanged. The output characteristic and circulating current with and without the load current feed-forward control is compared in this paper. Furthermore, the prototypes of parallel inverters are built to verify the theoretical analysis.