The Research Of Grid Connected Photovoltaic System

In recent years, along with the solar photovoltaic power generation technology continues to mature and popular, solar photovoltaic power generation is gradually from the special to civil applications, by the auxiliary energy to the energy transition, especially the emergence of grid connected photovoltaic system, the application prospect of solar photovoltaic power generation more bright. The world energy crisis coming, promote the photovoltaic power generation began large-scale use in developed countries.This paper from the solar power status and significance is expounded, and studies the composition system of solar photovoltaic power generation, while the research on the classification of photovoltaic power generation system. Introduces the performance and structure of grid connected photovoltaic system inverter. To select the appropriate inverter in accordance with the requirements of inverter for grid connected photovoltaic system. In order to improve the work efficiency of photovoltaic system, the principle and method of tracking the maximum power point. Islanding effect on how to measure and control the PV system to do the analysis. The scheduling of grid connected photovoltaic system research. The Simulink model of islanding detection method for simulation part built active frequency drift method and voltage feed forward positive feedback, calculated the parameters of the system, implementation of MATLAB code and the output waveforms and results are analyzed.The various phase shift detection methods in the detection zone RLC circuit resistor load is14.4ohms. Conclusion, the AFD method in the L value is very small (corresponding to larger C), NDZ is very narrow; when the L slowly increases while C decreases, NDZ gradually becomes wide; with RC load, AFD detection may fail, because the RC load exhibits ahead of the phase offset phase frequency offset difference in a small inductance, capacitance, large, power factor close to1of the AFD load detection will fail, because the high quality factor. For islanding detection method of voltage feedforward feedback, when M is0.98, the simulation results: the detection time is0.21～0.1=0.11s. The following conclusion can be drawn, if M takes off1is too large, will cause a transfer line has no power flow.