Research On Single-Phase Grid-Connected Photovoltaic Inverter

Using solar power is in the current serious environmental pollution in our country,the inevitable trend of resources,under the situation of lack of solar energy is not only a renewable green energy,and in many areas in China has rich too,can make full use of solar energy,will be one of the prerequisite for the sustainable development of our country electric power,the utilization and research of its is increasingly extensive and necessary.In the process of photovoltaic power generation systems,inverter is the core of the realization of energy conversion and control,the performance of the inverter and to a large extent determines the system stability and efficiency of power generation,under the situation of photovoltaic power generation cost is higher,the development of photovoltaic(pv)grid inverter is extremely important.Paper first analyzes the development status and application prospect of photovoltaic power at home and abroad,the photo-voltaic(pv)grid power generation system,structure,and the kinds of interconnection standards are reviewed.Were compared and analyzed,to meet the demand of small users of photovoltaic(pv)grid inverter main circuit structure and control strategy,is proposed in this paper,the design of single-phase photovoltaic(pv)grid inverter adopts two levels of grid structure and improve the fixed frequency of SPWM current control strategy.Eventually determine the study of a single-phase power is 3 kw,grid voltage220 v inverter topology and its main circuit parameters,output filter parameters design,and the amplitude frequency characteristics analysis.Design of single-phase photovoltaic(pv)grid inverter,this paper used the two levels of the isolation structure,level before using the Boost booster circuit to complete the booster and system of pv array output voltage in dc side of maximum power point tracking(MPPT),after class to adopt single phase full bridge inverter,realize grid inverter function.This article also for photovoltaic maximum power point tracking technology is analyzed,by comparing several commonly used MPPT algorithm,proposed to improve the variable step disturbance observation method,using MATLAB/Simulink simulation analysis.Control system is to adopt the TMS320F2812 chip of TI company to control,including the MPPT track control,dc bus control,booster and inverter pulse width control to ensure that the grid inverter output harmonic current and power grid voltage frequency and phaseFinally,in view of the above analysis and research,according to the total control scheme of the system,gives the main circuit structure and parameter selection of system design,simple and feasible control scheme,system work stable and reliable,good performance.