Research On Battery Charge And Discharge Control Strategy In Independent Microgrid

In the 21 st century,resource panic and environmental issues are driving more and more scientists to explore emerging energy.Many workers have turned their attention to clean renewable energy.The development and utilization of solar energy,tidal energy and geothermal energy have become Hot spots for scrutiny research [1].By the end of 2018,China’s new energy generation accounted for about 28% of total power generation,but environmental conditions are the biggest bottleneck limiting the large-scale use of clean energy,due to cloudy,rainy,snowy,windy weather and day and night alternation.Clean energy has existed since the birth of this congenital deficiency.The battery charge and discharge control strategy in the independent microgrid studied in this paper is based on a national demonstration project in southwestern China,combined with the special geographical environment of the region,and proposed the radial flow turbine as the main power supply microgrid of the microgrid.The micro-source uses the battery as a micro-source for fast coordination of micro-network transient fluctuations.As a micro-source for sustainable use,the battery can solve the problem of poor power quality of the micro-grid by controlling the instantaneous output of the battery.The main work of this paper is as follows:Firstly,the overall structure of the microgrid is introduced.Three different working conditions of the microgrid are discussed.The theoretical analysis of the radial turbine,diesel generator and battery is carried out.The mathematical model and simulation model are established,and the simulation model is established by using simulink.Test to match the established simulation model with the actual out-of-device characteristics.Secondly,the different operation control modes of the microgrid are introduced.The different control modes are compared.The advantages and disadvantages of various control modes are theoretically analyzed,and the mathematical model and the simulation model are built.By analyzing the output of three micro-sources under three working conditions ofmicro-grid,the V/F control strategy was selected initially,and the improved PQ and V/F joint control strategy was proposed according to the joint control strategy of PQ and V/F.And the improvement principle is emphasized in the improved PQ and V/F joint control strategy.For the special power supply mode of this subject,the joint control strategy of PQ and V/F is applied to the microgrid control for the first time.Finally,the simulation model is analyzed by using DIgSILENT and Matlab/simulink tools.The V/F control strategy and the improved PQ and V/F joint control strategy are compared.It is concluded that if the transient adjustment time is the main limit target,The V/F control strategy transient adjustment time is reduced by 90% compared with the improved PQ and V/F joint control strategy;if the transient overshoot is the main limiting target,the PQ and V/F joint control strategy transient overshoot It is 80% less than the V/F control strategy.The choice of this case control strategy is based on the special power supply mode in this case and the impact of load on the microgrid fluctuation under three different working conditions.In order to meet the stability of the microgrid power supply and high power quality,a comparison method is adopted,from two Select the optimal control strategy in the control strategy.