中文摘要：

光伏并网逆变器作为一个安全可靠的并网逆变装置,必须要能及时检测出孤岛效应.以三相光伏逆变器为对象,提出了一种新型的主动式孤岛检测方法一相位正弦扰动法,即在逆变器输出电流的相位中加入微弱的正弦扰动,通过检测公共耦合点PCC （point of common coupling）电压q轴分量的幅值来判断孤岛的发生;推导了孤岛发生后PCC电压q轴分量的幅值与负载品质因数的关系;给出了检测出孤岛的定量条件;论证了该方法不影响输出电流的过零点、幅值和基波;阐明了在负载平衡的情况下此法不存在检测盲区;最后进行了Matlab/Simulink仿真,验证了提出方法的有效性。

英文摘要：

As a safe and reliable grid-connected inverter,the photovoltaic grid-connected inverter must be able to detect islanding in time.For the sake of three-phase photovoltaic grid-connected inverter,a novel proactive islanding detection method,i.e.phase sinusoidal disturbance method,is put forward,which adds slight sinusoidal disturbance the phase of the inverter＇s output current and the islanding status is judged by detecting the amplitude of q axis component of the voltage at the point of common coupling （PCC）.The relationship between the amplitude of q axis component of PCC voltage and the quality factor of load is deduced after islanding.The quantitative condition of detecting islanding is provided.This method is demonstrated to have no influence on the zero crossing point,amplitude and fundamental wave of the output current.It is also indicated that non-detection zone does not exist under load balancing.Finally,in order to verify the effectiveness of the proposed method,Matlab/Simulink simulation is conducted.