It has been found that both the number of paralleled grid-connected converters and the filter inductance value will affect the system’s stability in weak grid condition. However, a quantitative study on this effect is missing in the current literature. The main contribution of this paper is to quantitatively evaluates the influence of the number of paralleled grid-connected converters as well as the inductance value of the L filters on the system’s stable region. It is first revealed that, when the same controller design principles are applied for L-type grid-connected converters, the stable region of the paralleled grid-connected converter system is dependent on the ratio between the filter inductances and the number of paralleled converters. Specifically, the stable region is proportional to the ratio. Compared to the qualitative analysis in previous work, this finding can provide quantitative guidelines on the filter inductors or control system design for grid-connected converter applications in weak grid. Finally, experimental tests are carried out using two paralleled grid-connected converters to confirm the findings.

已经发现，并联并网转换器的数量和滤波器电感值都会影响弱电网条件下系统的稳定性。但是，当前文献中缺少对此效应的定量研究。本文的主要贡献是定量评估并联的并网转换器的数量以及L滤波器的电感值对系统稳定区域的影响。首先揭示出，当相同的控制器设计原理应用于L时，对于并联型的并网转换器，并联的并网型转换器系统的稳定区域取决于滤波器电感和并联的转换器数量之间的比率。具体地，稳定区域与比率成比例。与先前工作中的定性分析相比，该发现可以为弱电网中并网变流器应用的滤波器电感或控制系统设计提供定量指导。最后，使用两个并联的并网转换器进行实验测试以确认发现。