Research On Distributed Generation Based On Photovoltaic Microinverter

Solar Photovoltaic power is one of the energy development program,which is the focus of the new energy industry.In recent years,with the rapid development of photovoltaic industry,photovoltaic inverter has become very popular.From the large power rating for the first 20 kw and 40 kw centralized photovoltaic grid inverter,then 1 kw to 3 kw power level for the branch type grid inverter,finally to the present power levels in 50 w and 400 w AC module,also called micro-inverter.At present the trend of the development of the photovoltaic inverter power level is more and more small,because it can better improve the efficiency of between each module,but at the same time the system is considered to be one of the important development direction of connecting grid system in the future.Monitoring and control system is one of the important part of photovoltaic power generation systems.It is significant for the safe and reliable of running efficient of pv inverter.Therefore,the study of monitoring system of photovoltaic power station is very important to improve the performance of the entire photovoltaic power generation systems.The paper select interleaved flyback type microinverter as the research object.The first,The paper introduces the principle of power generation of photovoltaic cell.And the diode equivalent model and engineering calculation model of photovoltaic cell are established.The second,the MPPT of photovoltaic cell is realized by simulink using fix-step perturbation observation method,based on the calculation moder of photovoltaic cell engineering.The third,the paper analyzes the basic principle of interleaved flyback type microinverter,and the DCM and CCM operation mode of interleaved flyback type microinverter is carried out.The AC small signal model of interleaved flyback under the operation mode of CCM is established,and the control strategy and algorithm is put forward.Finally,the model of interleaved flyback type microinverter,which is in this paper,is simulated and analyzed,the results show that the phase of current,which is created by the interleaved flyback type microinverter,is the same to that of grid,and the harmonic distortion rate is less than 5%,which meets the grid standard.