中文摘要：

受微电网线路阻抗不匹配等因素的影响，传统的下垂控制难以按照下垂增益合理分配无功功率，为了提高微电网中分布式微源输出无功功率的均分精度，又不至于降低电压质量，提出了一种基于同步思想的微电网无功均分改进下垂控制策略。该方法在传统下垂控制的基础上引入了无功补偿和电压恢复机制，利用中央控制器发出的低带宽同步信号的触发，无功补偿机制将修改下垂特性曲线的电压偏置，改善无功出力分配精度，而电压恢复机制则补偿由此造成的输出电压的降低，实现电压恢复。从理论上证明了该算法的稳定性，且仿真和实验结果均表明，改进下垂控制的无功均分方法实现了负荷有功和无功功率的合理均分，并具有良好的动态和稳态性能。

英文摘要：

Due to the property of line impedance and other factors in microgrid, reactive power supplied by distributed generation units could not be shared accurately based on their conventional voltage droop gains. To improve the reactive power sharing accuracy of DG units and maintain the voltage quality in microgrid, the paper proposed an improved droop control of reactive power sharing strategy which was based on the synchronous thought. The proposed method is realized through the reactive power compensation operation and the voltage recovery mechanism. The reactive power compensation operation changes the voltage bias of the conventional droop characteristic curve, which is activated by the low-bandwidth synchronization signals from the central controller so that the reactive power sharing among distributed generation units is effectively improved. Meanwhile, the voltage recovery mechanism was employed to compensate the decline of DG output voltage in the process. In theory, this paper has proved the stability of the method. Simulations and experimental results also show that the improved droop controller can achieve good load active and reactive power sharing, and also has a good dynamic and steady-state performance.