The Research Of 5 Kw Non-isolated Photovoltaic (pv) Grid Inverter

In todays world, the problems of energy and environment have become a global hot topic and under the background of environment being worse and energy drying up, development and utilization of new energy have received unprecedented attention and concern. Photovoltaic power generation with character of low pollution and renewable energy will be a more broad development in the future. Inverter is one of the most critical part in the grid-connected power generation system. Efficiency of structure type is directly related with its use value. General bridge topology structures exist some disadvantages, such as low efficiency, big leakage current and so on.H6 bridge inverter topology is proposed in this paper. Compared with other types of bridge inverter topology, it improves low efficiency and leakage current. The main research includes the following aspects:1.Compare and analyze the principle, efficiency and performance of several common H bridge topology structure, and propose H6 bridge inverter topology with the character of higher efficiency, smaller leakage current and so on.2.Choose the L filter circuit and design its parameter in detail.3. Analyze the PV gird control technology, explore the principle, advantages and disadvantages of PR control technology, and then similarly explore the principle, advantages and disadvantages of PI control technology. Aimed at the deficiency of PI control technology, the paper proposes a new control technology named PI+voltage feed-forward control. The new control technology improves stability and anti-interference ability of the system.4.Set up the simulation model the paper described on the platform of Matlab/Simulink, PI control and PI+voltage feed-forward control are simulation conducted. The simulation results show that the ability of anti-interference and harmonic rejection of the system have improved a lot to some extent compared with just PI control. A 5KW prototype is developed, and do some related experimental verification. Simulation and experimental results show that H bridge topology has high efficiency and low leakage current. And PI+voltage feed-forward control could improve the ability of anti-interference and harmonic rejection of the system.