微电网并网逆变器下垂控制策略的改进

Improvement of droop control strategy for grid-connected inverters in microgrids

微网中采用的传统功率下垂控制算法存在缺陷,会因为控制线路阻抗的差异出现控制误差。该文分析了微网中并联逆变器的环流现象产生原因以及传统下垂算法理论,在考虑逆变器输出阻抗和线路阻抗中阻性分量的基础上,提出了功率下垂解耦控制方法。并针对其解耦后未能改善功率分配不均的现象,该文提出了一个改进下垂控制算法。该改进算法通过对下垂参数的调整使功率分配不均的问题得到了改善。该文最后采用Matlab/simulink进行仿真,验证了改进控制算法的先进性。采用改进算法后,可以减少微网逆变器控制误差,同时得到较好的动态响应。该研究可提高微网控制精度。

The traditional droop characteristic microgrids may result in control errors because of the output impedance and line impedance. In this paper, the active and reactive circulating current of the parallel system model and the traditional droop characteristic were analyzed. Considering the output impedance and line impedance, the reactive power sharing improperly was analyzed. Because of the improper power sharing problem can not be improved by the control scheme, the improved power decouple control scheme was proposed. The improved droop algorithm can improve the condition of the power sharing. And then the proposed control scheme was verified by the MATLAB/Simulink simulation. The improved algorithm reduced the inverters control error, and got a better dynamic response. The study improves the control accuracy of the microgrids.