中文摘要：

光伏并网系统中产生孤岛时,不仅对设备造成破坏,而且危及维修人员的安全.传统的被动检测方法在逆变器所带的本地负荷与其输出功率接近于匹配时失效,主动检测法添加的扰动又会降低系统稳定性和减慢检测的速度,直接影响并网电能质量.针对上述问题,提出一种基于最优控制的快速孤岛检测方法,通过对逆变器端输出电压的幅值、相位和频率的变化差值建立数学模型,采用二次型最优控制算法进行孤岛检测.通过理论分析、建模和仿真研究,验证了该方法的可行性,检测时间短,具有一定的工程应用价值.

英文摘要：

When island occurs in photovoltaic （PV） grid-connected system, not only equipment is damaged, but also the life safety of people was endangered. The traditional passive detection method in the inverter with local load and output power close to matching fails, and active detection method to add perturbations will reduce the stability of the system and slow down the speed of detection, direct effects of grid power quality. Aiming at these problems, a kind of optimal control method for islanding detection was put forward. Based on the changes of inverter output voltage amplitude, frequency and phase difference, a mathematical model was built, using two quadratic optimal control algorithms for islanding detection. Through theoretical analysis, modeling and simulation, the feasibility of the method is verified with short testing time and a certain application value.