Simulation And Design Of Single-phase Photovoltaic Grid-connected Power Generation System

Nowadays,energy and the environment issues are two major challenges for human development.It’s impossible to tackle the issues solely relying on energy conservation and emission reduction.Solar energy is a renewable energy source,which is of great significance to the energy strategy and has attracted the attention of many countries.There is no doubt that the two stage photovoltaic grid connected system will be widely promoted as an important form of power supply in the future.This paper is aimed at the simulation and design of the two stage grid connected power generation system.Therefore this paper first analyzes the mathematic model of photovoltaic cell and the commonly used maximum power point tracking(MPPT)control means,then establishes the simulation model of photovoltaic cell and variable step disturbance observation method Matlab/Simulink,and studies the output characteristics of photovoltaic cells.After comparing the main circuit of two stage single-phase grid connected photovoltaic system,this paper determines the overall control scheme of the boost circuit,the single-phase full bridge inverter circuit structure and two stage power converter,moreover it makes the selection and calculation of main circuit parameters.The double closed loop PI control is adopted in the grid connected inverter,and the detailed process of the parameter calculation of the control system is given.It also analyzes hardware design and software scheme based on the DSP control system presenting some hardware circuit and software process.Finally,the simulation model and the running results are given to prove the feasibility and effectiveness of the proposed scheme,by verifying the MPPT tracking and boost function of the former stage,and the output current is the same as that of the grid voltage.