| In recent years,the global resource problem has become more and more prominent,environmental pollution has become increasingly serious,therefore,people’s growing concern about renewable energy.Among them,renewable energy in the photovoltaic power generation is the focus of attention.PV system can work in the grid mode,independent mode,and self-balanced,self-regulation ability,to a large extent can reduce the disturbance to the power grid,greatly increasing solar energy efficiency.General photovoltaic systems,by the load,solar panels,public power grids,energy storage equipment and micro-network system controller and other components.Among them,photovoltaic systems are essential components for energy storage equipment.The use of photovoltaic systems in the higher frequency of energy storage equipment,is inexpensive,excellent performance of lead-acid batteries.However,the biggest feature of photovoltaic energy is the randomness of the strong,which greatly shorten the use of lead-acid battery time,therefore,want to increase the battery life,we need to use more efficient and scientific charge and discharge control technology.In recent years,the level of science and technology of the whole society has been continuously improved,and new energy and its corresponding technologies have been paid more and more attention.Two-way DC-DC converter is such a widely used technology,it has been successfully applied in the field of electric vehicle energy management system,solar power system,DC power supply system and air point source system.Among them,the independent photovoltaic power generation system,but also the two-way DC-DC converter as a transmission hub,to complete the energy storage unit and the DC bus between the energy transfer.Therefore,the study of bi-directional DC-DC converter control technology is very valuable.This paper mainly from the charging method,the research value is not appropriate,the current method of reducing the use of rechargeable battery overcharge,undercharge and so on,to explore the battery charge and discharge control technology in the application of independent photovoltaic systems,Scientific Battery SOC(State Of Charge)Current Decreasing Charging Method.The specific operation is to first calculate the charge current attenuation coefficient(Maas law),according to the law of the battery SOC charge rate real-time estimates,and then use the highest charge voltage to stop the charging process.To determine the abnormal battery discharge process or not,you can change the DC bus voltage method to achieve.Then,based on the concept andmethod of bidirectional DC-DC converter,a two-way full-bridge DC-DC converter is proposed,and its working principle is introduced,which is used as the main circuit of charge and discharge control.This type of converter is generally charged and discharged in two modes.In the charging mode,the drive signal will appear on the high-side switch and the low-voltage side will block the drive signal.In the discharge mode,the drive signal will appear in the low-side switch,High-voltage side of the closed drive signal,the two models exactly the opposite.In addition,the existing problems in the existing converter operation mode are studied,and then the control model of the two-way full-bridge DC-DC converter is studied and the stability of the closed-loop system of the converter is analyzed.Out of the main circuit model used.Then,the MATLAB/SIMULINK simulation is carried out on the determined main circuit and the selected charging and discharging mode.The main circuit and the selected charging and discharging method are verified.Finally,the design of the battery charge and discharge system part of the hardware circuit and software flow chart,and finally come to TMS320F28335 as the master chip charge and discharge control system.The demonstration analysis shows that the system can normally switch the battery charge and discharge mode,and select the appropriate charge and discharge path,and correctly estimate the battery SOC and so on. |
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