中文摘要：

常规下垂控制对线路阻感比具有高度依赖性,难以对线路阻抗常呈阻性或阻感性的低压微电网的电能质量实现有效控制.基于通用下垂控制原理,提出了改进型PQ-fU功率耦合下垂控制方法,并通过结合上层能量优化管理与引入比例复数积分（PCI）电压控制技术,设计了一种改进型PQ-fU多环控制策略.该控制策略不仅在线路呈阻感特性情况下仍能实现对低压微电网电能质量灵活而有效的控制,而且适用于并网/孤岛2种运行模式,可对上层能量管理系统给定的参考指令进行快速跟踪,实现各分布式电源输出功率的合理分配.在MATLAB/Simulink中对低压微电网逆变器并联运行系统的控制效果进行了对比研究,结果验证了所提控制策略的有效性和优越性.

英文摘要：

For the effective control of power quality,the conventional droop control,which is highly dependent on the resistance-inductance ratio of line,is hardly applicable to low-voltage microgrid because it is normally resistive or inductive.An improved PQ-fU power-coupling droop control is proposed based on the theory of conventional droop control and,combined with the high-level energy optimization management and the PCI （Proportional Complex Integral） voltage control,an improved multi-loop control strategy is designed,which flexibly and effectively controls the power quality of resistive or inductive low-voltage microgrid,quickly traces the reference instruction from high-level energy management system and reasonably distributes the output power of distributed generations,suitable for both grid-connecting and islanding modes.The control effect of parallel inverter system in low-voltage microgrid is studied with MATLAB/Simulink,which verifies the effectiveness of the proposed control strategy.