一种新的自适应相位偏移并网孤岛检测方法

A new adaptive phase shift method for islanding detection of grid-connected inverters

孤岛检测是分布式发电并网研究的难点,特别是在逆变器输出与负载功率平衡时难以检测出孤岛。频率或相位偏移等主动检测方法在逆变器输出与负载相位匹配时孤岛检测失效。本文提出了一种新的孤岛检测方法——自适应相位偏移法。该方法使逆变器输出电流的相位周期性累加式变化,同时检测频率的变化来调节相位的正反馈,有效地打破逆变器输出和负载之间的功率平衡或相位匹配,从而快速检测出孤岛状态,且不存在检测盲区。仿真结果证明了其可行性。

It is difficult to detect islanding in distributed generation research, especially when power balance between the output of inverter and the load. Frequency or phase shift method is ineffective when the phase match between the output of inverter and the load. A new method for islanding detection is proposed in this paper, that is the adaptive phase shift method, which makes the phase of output current of inverters change accumulatively and periodically. The system detects the change of frequency to adjust the positive feedback of the phase at the same time. It can break the balance of the output power or the phase match between inverters and loads effectively to implement a fast islanding detection. There is no non detection zone with this algorithm. The theoretical analysis is verified by simulation experiment.