Motivated by the increasing interest in DC microgrids, we study the distributed secondary control problem of DC microgrids which aims to simultaneously guarantee load current sharing and DC bus voltage restoration. In particular, we analyze in-depth the effects of nonlinear constant power loads (CPLs), and successfully establish an upper bound for CPLs to guarantee the stability of DC microgrids. This established bound is less conservative than existing counterparts, allowing the connected power of CPLs to be much larger than that of linear resistive loads. Moreover, this bound explicitly reveals the connections between CPLs and droop gains, i.e., the upper bound of CPLs can be increased by decreasing droop gains, and vice versa. Three case studies are provided to verify the established results.

中文翻译：

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直流微电网的分布式控制：恒定功率负载的宽松上限


在对直流微电网日益增长的兴趣的推动下，我们研究了直流微电网的分布式二次控制问题，旨在同时保证负载电流共享和直流母线电压恢复。特别是，我们深入分析了非线性恒定功率负载 （CPL） 的影响，并成功建立了 CPL 的上限，以保证直流微电网的稳定性。这个既定的边界比现有的对应物不那么保守，允许 CPL 的连接功率远大于线性电阻负载的连接功率。此外，该边界明确揭示了 CPL 和下垂增益之间的联系，即 CPL 的上限可以通过减少下垂增益来增加，反之亦然。提供了三个案例研究来验证已建立的结果。