Research On Power Control Strategy Of Energy Storage Battery Pack Based On Operation Characteristics Of Lead-carbon Battery

The development and utilization of renewable energy such as wind energy and solar energy is an important approach to low-carbon energy transformation.Microgrid is widely used as an effective way to undertake large-scale access to distributed renewable energy.Affected by the volatility and intermittency of wind and light,the power of wind power and photovoltaic power fluctuates greatly,which affects the safe and stable operation of the power grid when directly connected to the grid.Battery energy storage system(BESS)can effectively suppress the fluctuations of wind power and photovoltaic power.The effective way for its large-scale application is to connect batteries in series and parallel to obtain higher voltage level and larger storage capacity.Due to the differences in battery manufacturing processes and operating conditions,there is an inconsistency between the individual cells in battery pack,irregular charging and discharging during smooth power fluctuations can cause the battery state of charge(SOC)to exceed the limit,deteriorate the consistency of battery pack and cause overcharge or overdischarge of some single batteries,which endangers the battery life and weakens the adjustment ability of energy storage battery pack.In view of the above problems,this paper selects lead-carbon battery with high cost performance and safety as the research object,and designs the power control strategy of energy storage battery pack based on the operation characteristics of lead-carbon battery to improve the performance of battery pack and maximize the regulation ability of energy storage system.The SOC estimation method of lead-carbon battery and the maximum power state prediction method based on battery current and boundary SOC constraints are analyzed.The causes and manifestations of inconsistency in lead-carbon battery pack are studied,based on the charge/discharge experiment of lead-carbon battery pack,the consistency deterioration phenomenon that the voltage dispersion of single cell increases with the increase/decrease of SOC is revealed,which lays a solid foundation for the design of subsequent power control strategies.An example system for lead-carbon battery energy storage to suppress the power fluctuation of the microgrid containing wind power and photovoltaic into the main grid is designed.The power control strategy of energy storage battery pack considering the maximum power state constraint,SOC constraint and the inconsistency of battery pack is proposed respectively.The comprehensive control strategy of energy storage battery pack with the above-mentioned constraints is designed to reduce the rate of SOC reaching the limit and the rate of battery pack consistency deterioration,and improve the overall performance of battery pack.Based on the measured data of a microgrid demonstration platform,the capacity of energy storage battery pack is configured based on the probability statistics results of power fluctuations at the grid-connected points.On the Matlab/Simulink simulation platform,the power control strategy simulation model of energy storage battery pack is built,and the control effects of different control strategies are compared and analyzed under lower and higher SOC conditions of energy storage battery pack respectively.The correctness and effectiveness of the proposed power control strategies are verified.