Design And Research Of Household Independent Photovoltaic Storage Inverter

Solar energy,as a renewable resource with simple operation and use,low cost and safety,has been highly valued by all countries in the world.Household photovoltaic storage power generation system can directly provide the required power for the family,and greatly reduce the load of civil power in the power grid,which has been widely used in most areas of developed countries.Through consulting a large number of domestic and foreign documents,and the current technical status of household photovoltaic inverter is analyzed.Based on the average load of household appliances,a 5kW household independent photovoltaic storage inverter is designed.In view of the possible local occlusion and hot spot effect of photovoltaic array,particle swarm optimization combined with improved variable step conductance increment method is used to track the global maximum power point,to prevent working at the local maximum power point,resulting in a large amount of waste of photovoltaic energy.Two-way DC-DC circuit is used to realize the photovoltaic energy storage function to meet the needs of energy in daily household life.The photovoltaic energy storage function is realized by Bidirectional DC-DC circuit to meet the power demand in the daily life of the family.The specific research contents are as follows:Firstly,the overall framework of the photovoltaic storage inverters is described,and two-stage topology is selected as the frame.This paper analyzes the generation principle and output characteristics of photovoltaic array,and studies the multi peak characteristic curve of photovoltaic array output when there is occlusion or hot spot effect.Then the maximum power tracking algorithm of the photovoltaic array is studied,and an improved MPPT algorithm which combines the global search particle swarm algorithm with the local search variable step conductance increment method is proposed.Secondly,compared with several classic DC-DC circuits,the Boost circuit is selected as the pre-stage DC boost circuit of this design,and the two-way Buck-Boost circuit is selected as the topology circuit in the battery energy storage link of the system.The working principle of the two DC-DC circuits is analyzed and studied.In this design,the back-end DC-AC circuit adopts the one-way full bridge inverter circuit and a dual-power supply circuit is designed at the output and its working principle is briefly described.Then,in the aspect of hardware design,DSP28335 is selected as the core control chip of the photovoltaic storage inverter,and the energy storage elements and switching devices of Boost circuit and bidirectional Buck-Boost circuit are calculated and selected.IPM(intelligent power module)is selected as the switch device in the back-stage inverter circuit,and an auxiliary circuit is designed.In the aspect of software,the overall software flow of the system is designed,and the maximum power point tracking algorithm and bidirectional DC-DC circuit logic control algorithm are implemented.Finally,on MATLAB/Simulink,the 5kW household photovoltaic storage inverter studied in this paper is simulated,including photovoltaic array model and output characteristics,maximum power point tracking,bidirectional Buck-Boost charging and discharging circuit and single-phase inverter circuit,to verify the rationality and correctness of the photovoltaic storage inverter.Through PCB manufacturing,manual welding,debugging,etc.,a 5kW household photovoltaic storage independent test prototype is made.On the laboratory power electronics test platform,the prototype is tested,and the relevant test results are obtained,which show that the prototype can meet the actual application requirements.