适用于多台逆变器并联运行的孤岛检测方法

An island detection method for parallel operation of multiple inverters

当前孤岛检测技术的研究主要集中在单台逆变器,随着逆变器被广泛连接到公共电网,多台并联运行的情况更为普遍,因此,以典型的两台逆变器并联运行为例研究其孤岛检测方法具有重要的研究意义。分析了主动移频式方法的检测原理,提出了一种新型带正反馈的主动频率偏移法,并对两台逆变器并联运行时分别采用传统与改进方法和同时采用改进方法时的检测盲区展开分析,最后,通过模型仿真验证了盲区分析结果的正确性。仿真结果表明,所提方法能够解决负载对单一方向频率扰动的平衡作用的问题,而且对并网电流的影响较小。

Currently,research on the island detection technology mostly focuses on a single inverter.Parallel operation of multiple inverters is more common as inverters are widely connected to the public grid.Therefore,the island detection method is studied,taking the parallel operation of the typical two inverters as an instance.The detection principle of the active frequency drift method is analyzed,and then a new active frequency drift method with positive feedback is proposed.Meanwhile,the non-detection zone in the parallel operation of two inverters is analyzed by using the traditional method and the improved method respectively.Finally,the correctness of the non-detection zone analysis is verified by model simulation.Simulation results show that the proposed method can solve the balancing problem of the frequency disturbance in a single direction,and its effect on the grid current is smaller.