一种改进型光伏并网逆变器孤岛检测方法研究

孤岛检测是光伏并网逆变器系统运行的重要功能之一,为了实现快速准确的孤岛检测,同时减小对电能质量的影响,提出一种改进型主动式孤岛检测方法,即周期性正负相位偏移法。首先建立了加入正/负偏移相位后逆变器在孤岛运行时公共耦合点电压的角频率与负载品质因数、负载谐振角频率及所加偏移相位之间的函数关系;然后设计了消除检测盲区的正/负相位偏移参数,确保提出的方法对电能质量影响很小;最后在IEEE Std.929-2000标准中规定的最恶劣情况下进行了仿真和实验研究。实验结果验证了提出方法的有效性。

Research on An Improved Islanding Detection Method for Photovoltaic Grid-connected Inverters

Islanding detection is one of the important functions of photovoltaic grid-connected inverter system. In order to achieve rapid and accurate islanding detection, and reduce the impact on the power quality, an improved active islanding detection method was proposed in the paper. Firstly, the functional relationships between the angular frequency and load quality factor of the common coupling point voltage, and between the load resonant angular frequency and the offset phase were established when adding the positive/negative offset phase in the island. Then, the positive/negative phase shift parameters for eliminate non-detection zones(NDZ) was designed to ensure that the proposed method have li-ttle impact on power quality. Finally, the simulation and experimental studies are carried out in the most severe cases specified in the IEEE std. 929-2000 standard. The experimental results verify the effectiveness of the proposed method.