带孤岛检测的两级式光伏并网系统重复控制技术

Grid-connected Repetitive Control with of Two-stage Grid-connected Photovoltaic System with Islanding Detection

实现了两级式光伏并网逆变器的设计和仿真。并网逆变器采用两级式拓扑结构,前级DC-DC整流部分使用Boost电路实现最大功率的跟踪控制,后级DC-AC逆变部分实现与电网的并网控制。针对孤岛问题,系统引入有源频率偏移检测技术,能较好地实现孤岛保护控制功能,且孤岛检测输出作为重复控制器的参考输入信号,进一步保证了并网电流与电网电压的同步。通过MATLAB软件建立模型进行仿真,结果证明本系统的并网电流符合并网要求,并能快速实现孤岛检测。

The article makes a further research on the topic of two-stage grid-connected photovoltaic system. Two level topological structure is adopted in the system. In order to realize the maximum power point tracking, DC - DC inverter is used. The DC - AC inverter of latter stage is used to achieve grid control. In order to solve the problem of island, a technology called Active Frequency Drif is introduced to the system. AFD can do a good job on islanding protection. What＇s more, the system takes the output of island detection as the input of the repetitive controller which strengthening the synchronism between grid electric current and voltage. Finally, a model is established by using the Matlab/Simulink, The results indicate that this system complies with the requirements of the grid and fast islanding detection.