自适应主动频率偏移孤岛检测新方法

针对带正反馈主动频率偏移法的不足,提出了改进措施。第1,用偏移电流相位方法来取代原算法中截断电流的方法以实现频率偏移目的;第2,采用新的自适应算法来动态调整正反馈参数。改进后的新算法在保留了传统带正反馈主动频率偏移法的同时,也克服了其不足。通过理论分析和Matlab仿真,证实了新方法的有效性。

Adaptive Active Frequency Shift Islanding Detecting New Method for Grid-connected Inverters

Anti-islanding protection is a mandatory feature for grid-connected inverters.Positive feedback active frequency drift method(AFDPF) is a typical islanding detection method.This method has the virtues of small no detected zone(NDZ) and working reliably.Its disadvantages include that the output current contains distortions and the positive feedback parameter can’t be adjusted instantaneously according to the changes of load.For the above shortcomings,the new method proposes improvement measures in two ways.First,the output current phase angle shift method is used to replace the original truncated current methods to achieve the purpose of frequency offset;second,a new adaptive method is used to dynamically adjust the positive feedback parameter.The new improved algorithm not only maintains the advantages of the traditional AFDPF method,but also overcomes the shortcomings of it.Theoretical analysis and simulation results validate the feasibility of the new method.