基于无功电流控制的并网逆变器孤岛检测

摘要

孤岛检测技术是并网逆变器运行所必须具备的关键技术.传统有源孤岛检测方法注入的扰动影响电能质量.为了解决该问题,提出一种基于无功电流控制的孤岛检测方法,通过控制无功电流使其产生的频率偏移方向与有功电流产生的频率偏移方向一致,使电网断开后频率迅速超过所设置的阈值而检测出孤岛,并对其进行量化分析,使孤岛算法在无检测盲区的基础上尽可能地减小对电网的影响.根据IEEE Std.1547测试标准对提出的方法进行仿真和实验验证.结果表明,提出的孤岛检测方法可以快速有效地检测到孤岛的发生,验证了提出方法的有效性.%The islanding detection technology is necessary for grid connected inverter. The conventional active islanding detection methods have negative impacts on power quality due to the disturbance injection. In order to solve the problem, a new islanding detection algorithm based on reactive current control is proposed. As a result, the frequency offset direction by the reactive current is the same as that by the active current. The frequency will exceed the detection threshold quickly and the islanding can be detected after grid disconnection. Islanding detection was quantitatively analyzed to reduce the negative impacts on grid without non-detection zone. Simulation and experiment are carried out according to IEEE Std. 1547. The results reveal that the proposed method can quickly detect the islanding, which verify the effectiveness of the proposed method.