Design And Research On Grid-connected PV System With Battery Energy Storage

With the continuous development of the global economy and society,energy consumption is also increasing rapidly.Solar is currently one of the best ways to use new energy,where photovoltaic(PV)power generation technology can be directly connected to the grid power generation system.Grid-connected photovoltaic(PV)system has become a main form of electricity production in the field of solar energy application.Large-scale PV grid-connected power generation system put forward new challenges on the stability of the power grid,and the grid-tied photovoltaic system with energy storage system integration becomes a regional system of power supply solutions.The system analysis and design in this thesis is based on the combination of battery energy storage with grid-tied photovoltaic power generation.A typical photovoltaic system includes solar panels,inverters,and performance monitoring control systems that track power production.Residential grid-tied photovoltaic(PV)systems in view of the present regulation ability causes inflexible problem during power outages from the grid.This thesis has designed a kind of combined battery backup storage to the interconnection of a grid-tied photovoltaic system.The system consists of 8kW solar array,600V MPPT charging controller,7.6kW grid-tied inverter and 600Ah battery bank.The battery components can be coupled with the power grid by AC or DC mode.In addition,the feasibility and flexibility of the MPPT charge controller is verified through the dynamic model built in the residential solar PV system.The study also found that rechargeable batteries such as lead-acid batteries,lithium-ion batteries,sodium sulfide and flow batteries are by far the best choice for renewable energy.Lithium iron phosphate battery(LiFePO4)was used in the simulation due to its low energy density and high power density making it suitable for stationary storage.Through the feasibility verification of the model control mode and the strategy control,we obtained the seamless switching between the on-grid and off-grid operation mode of the household photovoltaic system.It was found that the grid-connected photovoltaic system combined with reserve battery storage can effectively improve the stability of the system and reduce the cost of power generation.