Application Of Double-Battery Energy System In Photovoltaic Micro-grid

In order to use a series of new energy sources such as solar energy wind energy and so on,in order to alleviate a series of energy crisis caused by traditional fossil energy and serious pollution of the environment.The rise of microgrid plays a very important role.However,distributed energy has the characteristics of randomness,instability and so on.It will seriously affect the local load and large power grid will bring a series of adverse effects,such as voltage change,power fluctuation and so on.However,the introduction of energy storage system can be used to suppress the power fluctuation of new energy sources,such as photovoltaic,wind power,and so on,so as to meet the basic requirements of load and large power grid for power quality.Because the output power of the photovoltaic array can directly affect the efficiency of the photovoltaic power generation,the maximum power point of the photovoltaic array needs to be tracked.In this paper,we compare several of the frequently used photovoltaic MPPT algorithms,so I use a variable-step method of disturbance observation,and verify it on the experimental simulation platform.After comparing the advantages and disadvantages of many kinds of energy storage methods,I choose battery and battery dual battery energy storage system.On this basis,the equivalent model of battery and the structure model of bi-directional DC/DC converter are analyzed,and a dual-battery energy storage control strategy based on the control of DC bus voltage balance is presented.To a certain extent,the working state of the energy storage unit can be optimized to make full use of the residual capacity.In this paper,the control methods of three-phase inverter in grid-connected mode and off-grid mode are studied and compared because there are two operating modes:grid-connected mode and off-grid mode.The inverter adopts PQ control method in grid-connected operation mode and VF control strategy in off-grid operation mode.The simulation results show that these two control strategies can meet the basic requirements of power quality for large power grid and electric equipment.Finally,the balance of energy supply and demand of photovoltaic microgrid in the whole system is listed,and the simulation model of the whole structure operation of the system is built on Matlab/Simulik.The results show that the whole microgrid system can be stable,coordinated and orderly operation.It is verified that the dual-battery energy storage system can play an ideal role in suppressing the output power fluctuation in photovoltaic microgrid.