Photovoltaic Grid-connected Inverter And Its Simulation Study

With an increasingly serious problem of environmental pollution and energy shortages, Find a large reserve, clean, easily accessible new energy has risen to the world's agenda. There are many applications of solar energy, grid-connected photovoltaic system can be best represent the development direction and has become the mainstream of the solar energy application. Grid-connected inverter as a key component of the photovoltaic grid-connected system has been extensively studied.This paper based on a comprehensive study of grid-connected PV systems, focused on Single-phase grid-connected photovoltaic systems to conduct a comprehensive analysis. And from the main circuit topology of grid-connected systems, control strategies, system parameters, maximum power point tracking, as well as anti-island effect has done a detailed analysis and simulation.First, a detailed analysis of the photovoltaic power generation system's different main circuit topology structure and their work principle and features. On this basis, a relatively simple circuit topology was selected. And derivation of a simple and practical equations, which come up with a single-loop controller.Secondly, according to the main circuit and controller, the less frequently regularly compare used to produces a PWM wave. Use the Simpower systems which in the Matlab/Simulink toolbox built the whole circuit model and the simulation study.Furthermore, analysis of the various methods used in the maximum power point tracking. This paper presents a perturb-and-observe method based on the controller, and the theoretical calculation of the optimal values of various components. Finally structures circuit model and simulation study has confirmed the correctness of the design.Finally, islanding effect is the security of the grid-connected system. This paper analyzes the causes and effects of current island popular island effect of passive and active detection. Under this paper design features of the system, proposed the active frequency drift (AFD) to detect the island effect detailed analysis of its working principle, and do the simulation experiments.