中文摘要：

针对大量分布式并网逆变器接入到公共电网时逆变器侧与网侧之间的交互影响问题，从并网逆变器闭环系统外特性角度入手，提出在同步旋转坐标系下对LCL型三相并网逆变器入网电流和滤波电容电流双闭环系统进行输出阻抗建模。利用前馈解耦策略，将dq轴控制环路之间的耦合阻抗消除。考虑到实际系统多采用数字系统，将数字控制延时引入到模型中以更加精确地反映实际并网逆变器的输出阻抗特性。基于无dq环路阻抗耦合和引入数字控制延时情况下的精确输出阻抗模型，对多逆变器并网系统进行阻抗网络建模、谐振机理剖析及谐波交互影响分析。理论分析结果表明，逆变器产生谐波成分与电网电压谐波成分会加剧多模块并网系统入网电流的谐波畸变。仿真结果验证了所建输出阻抗模型的正确性及其在逆变器-电网交互系统性能分析中的有效性。

英文摘要：

Aiming at the interactive influence problems between inverter side and grid side when a large number of inverters are connected to the utility grid, from the standpoint of external characteristics, out-put impedance model of three-phase grid-connected inverter with LCL filters based on dual-loop control scheme of grid current and filter capacitor current were firstly proposed and deduced in the synchronous rotating reference frame. Then the feed-forward decoupling control strategy was introduced to eliminate the coupling impedances between the d and q axis control loop. Because the real system would be a digit-al control system, the control delay was modeled and incorporated into the developed model in order to improve the accuracy of output impedance characteristics. Based on the accurate output impedance model proposed above, the interactive influences and its harmonic resonance mechanism between the multiple inverter systems and the utility grid were modeled and analyzed. Theoretical analysis indicates that the harmonic components form inverter side or grid side will aggravate the grid current distortion in distributed generation system based on multi modules. Simulation results are presented to demonstrate the correctness and effectiveness of the output impedance modeling and system performance analysis method based on dis-tributed interactive network.