Research On Interleaved Flyback Micro-inverter For Grid-connected Photovoltaic System

In the context of global environmental degradation and a increasing shortage of energy, the clean solar energy has received extensive attention, and the photovoltaic industry has rapidly developed. Miniature photovoltaic system has been developing rapidly。 In the photovoltaic power generation system, due to the problems such as the photo crack and shadow of the photovoltaic panels, output of Single piece of photovoltaic modules will be affected. And this will cause a serious decline in the efficiency of photovoltaic power generation systems. Therefore, the power generation equipment which is connecting micro inverter with a single photovoltaic modules together and is equipped with MPPT control technology can achieve maximize solar power generation. Micro PV system can be produce modular, flexible system expansion, easy to maintain, with good potential for development.The interleaved flyback micro inverters as the research object in this paper, study the working principle, control technique, MPPT and islanding detection technology. Firstly, analyze the flyback converter and interleaved flyback circuit structure and working principle, use the active clamp circuit to solve the problem of transformer leakage energy problem, then analyze the working process of active clamp converter and last select the active clamp staggered flyback circuit topology as the main article. Based on the current PI controller and network control strategy, the control is simple and reliable and can output high quality electric current. Based on comprehensive consideration, the disturbance observer method is used to do the maximum power point tracking system to enlarge the output power. Anti-islanding strategy is to use active islanding detection frequency shift method to ensure power supply and equipment safety. Using matlab to establish control system simulation model to verify the correctness of the theory. At last, design the hardware circuit of the micro inverter, calculate and select the parameter of flyback transformer and master switch tubes and other components and finish the software design.