Research On 5kW Photovoltaic Micro-grid Inverter

To solve the contradiction between energy supply and demand, improving the global environment, countries in the world accelerate the development of new energy sources, especially for clean renewable energy study. Distributed Generation (DG) is a closely watched the form of electricity generation in recent years. It protects the environment, but also save energy and realize the diversification of energy use, which is considered a very promising power generation technology. However, access to a large number of distributed power generation system will have a huge impact to the operation of large power grids. To address the large grid and distributed generation between the access problem, Micro-grid structure comes into being. Photovoltaic Micro-grid inverter as a key part of the photovoltaic Micro-grid power system has been the research focus of national experts and scholars. Because of its traditional inverters do not have some of the good characteristics of domestic and foreign scholars. In this thesis, Micro-grid inverter principle, control strategies related research.First, from the perspective of photovoltaic power generation system, introducing Micro-grid photovoltaic power systems, grid-connected photovoltaic power systems, photovoltaic power generation system independent of the composition, advantages and disadvantages and so on. Comparison the characteristics and job characteristics of photovoltaic Micro-grid inverter and grid-connected inverter and the characteristics and job characteristics, made of photovoltaic Micro-grid inverter main circuit topology.Photovoltaic Micro-grid inverter has two modes of Grid-connected operation and Grid-disconnected operation. On the Grid-connected operation, photovoltaic Micro-grid inverter is connected with electricity, and electricity can be considered infinite capacity of the AC voltage sources, Micro-grid inverter with current control strategies more appropriate. Focus on hysterics current control, and control system modeling analysis. On the Grid-disconnected, photovoltaic grid-connected inverter micro important mainly for the local load power supply, with voltage closed loop control is more appropriate. By controlling the output capacitor voltage, the voltage stability critical loads, and critical load to ensure uninterrupted power supply. By simulation, Grid-connected mode and Grid-disconnected model have been mutual switched, the simulation results show that the proposed control method is reasonable and effective. Of the IPM model hardware selection, LC low-pass filter parameters and the static switch trigger circuit design, sampling circuit parameters were calculated related devices.Through simulation, the interaction of Grid-connected mode and Grid -disconnected modes between the switch is simulated, the simulation result proves the suggested control method is reasonable and effective. For hardware circuit of IPM model selection, LC low pass filter parameters and static switching trigger circuit design, sampling circuit relative device parameters are obtained.Finally, the full thesis summary of the system, there are still issues on the summary of further research and analysis projects.