CAJ | 학술논문

　　传统的下垂控制没有考虑逆变器之间线路阻抗的影响，直接应用于独立型微电网中分布式电源的控制，会影响系统的稳定性和功率均分。首先详细分析了采用传统下垂控制不能实现功率均分的原因，指出系统的线路阻抗和逆变器的额定容量成反比是传统下垂控制实现功率均分的充要条件；其次，提出了一种基于虚拟阻抗的改进下垂控制策略，引入虚拟电抗削弱线路阻抗模型中的阻性成分带来的功率耦合，引入系统电压反馈，通过改进电压/无功下垂控制解决线路阻抗不平衡带来的无功功率均分问题。采用该下垂控制能够实现系统功率的准确均分，并且改善系统的供电质量。仿真结果验证了该控制算法的有效性。
　　전통적하수공제몰유고필역변기지간선로조항적영향，직접응용우독립형미전망중분포식전원적공제，회영향계통적은정성화공솔균분。수선상세분석료채용전통하수공제불능실현공솔균분적원인，지출계통적선로조항화역변기적액정용량성반비시전통하수공제실현공솔균분적충요조건；기차，제출료일충기우허의조항적개진하수공제책략，인입허의전항삭약선로조항모형중적조성성분대래적공솔우합，인입계통전압반궤，통과개진전압/무공하수공제해결선로조항불평형대래적무공공솔균분문제。채용해하수공제능구실현계통공솔적준학균분，병차개선계통적공전질량。방진결과험증료해공제산법적유효성。
Due to the neglect of the impact of feeder impedance, the conventional droop control may result in instability and errors in proportional load sharing when implemented in islanded micro-grid. The inherent limitations of the conventional droop control are analyzed, and it is pointed out that the inverse proportion between the feeder impedance and the rated capacity is the necessary and sufficient condition for the power sharing; then an improved droop control based on virtual impedance is proposed to achieve accurate proportional load sharing, in which virtual impedance is introduced to reduce the power coupling brought by the resistance components of the feeder impedance model and an additional improved voltage/reactive power control is proposed to eliminate reactive power sharing errors caused by imbalanced line impedance. Accurate power sharing can be achieved and the load voltage can be maintained within the desired range by the proposed control strategy. Simulation results are provided to verify the analysis and design.