非隔离型光伏并网逆变器孤岛检测方法研究

传统的非隔离型光伏并网逆变器孤岛检测方法存在应用局限性强、性能不稳定的缺陷。针对这种现象,提出基于频率移动理论的非隔离型光伏并网逆变器孤岛检测方法。所提方法研究了孤岛效应的产生原因及其检测规范,构建出孤岛检测模型。模型使用基于频率移动理论的孤岛检测电路,对逆变器的电压、频率信号进行采集和主动干扰,获取到存在孤岛效应的逆变器,并随即调用模型断路芯片掐断逆变器输出,避免孤岛效应扩散。实验结果表明,所提方法拥有较强的孤岛检测能力和稳定性,可对现今无法检测到的孤岛效应盲区加以补充。

Non-Isolated Photovoltaic Grid Inverter Island Detection Method

The traditional non-isolated photovoltaic(PV) grid inverter island detection methods has strong limitation and instable performance. A new island detection method based on frequency shift theory is proposed. Islanding causes and detection specificationare analyzed in detail in order to build detection model. The islanding detection circuit proposed in the model is based on frequency shift theory. The voltage and frequency signal of inverters are collected after active jamming to identify inverters with islanding effect. After detection, the model circuit chip is called to cut inverter output and prevent spread of islanding. The experimental results show that the proposed method has strong ability to detect islanding. It is a good supplement of islanding detection blind area.