Research On Flyback Type Photovoltaic Micro-Inverter

At present, due to over-exploitation and utilization of non-renewable resourcessuch as fossil fuels, the energy crisis has become a worldwide problem. In this context,the inexhaustible solar received more and more attention. Photovoltaic is one of themain formal uses of solar energy. Building integrated photovoltaic (BIPV) powergeneration system is one of the focuses of this area.Building integrated photovoltaic power generation system is different from thetraditional large-scale photovoltaic power generation station. The traditionalphotovoltaic structure is improper to be used in the BIPV system because it is unable toeffectively solve the problem of partially shadow of the PV array. Firstly, this paperformulates a simulation model of the photovoltaic cell based on the physical mechanism.Based on this model, the output characteristics of PV cell in series and parallel underdifferent illumination is analyzed, the simulation results show the reason that thetraditional power structure can not be the used in the BIPV system.The ac module system which is suitable for application in the field of buildingintegrated photovoltaic system is studied, and point out that micro-inverter is the coreunit of ac module system. This paper introduced the development and the presentresearch results of the micro-inverter, and selected the flyback inverter as the mainobject of study. The working principle of the flyback inverter is described in detail. Theoptimized design of the inverter in discontinues mode is studied, including the design ofduty cycle, the selection of the magnetizing inductance, the turn ratio of high frequencytransformer and the parameters of the filter circuit. Based on these analysises, the properprameters of the inverter are fixed. A single variable MPPT algorithm is studied in thispaper, and the simulation results show the algorithm is effective. This paper alsoanalyzes the problems faced by the traditional flyback inverter in the application ofmicro-inverter. By analyzing the structure and power decoupling link of micro-inverter，it points out that the power decoupling link is the main factor that affecting the lifetimeof micro-inverter. The power decoupling link is improved through the introduction ofthe bidirectional dc-dc circuit, and the control scheme of the overall circuit isdesigned.The theoretical analysis are studied in Matlab/Simulink simulation platform,including the photovoltaic cell model, the effect of second power disturbances on thephotovoltaic battery output, and power The results show that the new decouling link works well. Finally, a flyback inverter experimental platform is designed, includes themain circuit, TMS320F2812controller, the hardware and software of the system isdesigned.