Research On Balancing Charge Control Of Energy Storage Battery In Photovoltaic Charging Station

In response to the energy crisis and environmental pollution,the global development and utilization of new energy has become an inevitable trend,and photovoltaic power generation has also become one of the main research and application directions in the new energy industry.The construction of photovoltaic charging stations can not only provide electric energy for electric vehicles,but also other electric equipment,so as to effectively reduce the amount of energy from the traditional power grid.which can effectively reduce dependence on traditional electric energy.However,there are still many problems with photovoltaic charging stations,such as the low photovoltaic conversion rate,unreasonable charging methods,and inconsistencies in capacity and voltage among individual batteries during the use of the battery pack,resulting in waste of energy and shortening the battery life,and increasing the construction cost of photovoltaic charging stations.The photovoltaic cell power generation efficiency,battery packs safely rapidly equalizing charging methods etc are importantly emphasized,and the corresponding photovoltaic balanced charging control system is designed in this thesis.Firstly,based on the analysis of the working principle of photovoltaic cells,and by building a mathematical simulation model,the output characteristics of photovoltaic cells as the environment changes is studied by the thesis.By means of analyzing and comparing the traditional maximum power tracking method,the improved incremental conductance method is proposed in order to improve the conversion rate of photovoltaic cells.According to different intervals to obtain a variable step size based on different intervals,the improved incremental conductance method based on the different step sizes is obtained in this thesis.Secondly,based on analyzing the working principle and mathematical model of the lead-acid battery,the charge and discharge characteristics of the battery are studied by simulation,the defects of the traditional charging method are analyzed.Combined with the characteristics of photovoltaic power generation,the MPPT algorithm is integrated in the traditional stage charging,and the characteristics of photovoltaic power generation are combined to integrate the MPPT algorithm in the traditional stage charging.The improved MPPT four-stage charging method is divided into four stages: trickle charging,MPPT fast charging,constant voltage charging and floating charging,which solves the problem of slow battery charging and extendsbattery life.The feasibility of the charging scheme is verified by simulation research.Then,against conflicting problems by using battery,the necessity of balanced charging is analyzed,and an improved active equalization method based on energy storage inductors is proposed in view of the characteristics of traditional dissipative passive equalization and non-dissipative active equalization schemes.The feasibility of the scheme is verified by simulation research.Finally,according to the requirements of photovoltaic charging control system,the system hardware and software are designed.The hardware part mainly includes MPPT circuit,MOSFET driving circuit,information acquisition circuit,equalization control circuit etc.The software part mainly includes MPPT algorithm,four-stage charging algorithm,equalization charge control etc.Then under the conditions of the laboratory,a hardware and software platform of the photovoltaic equalization charging system is established,and the feasibility of the photovoltaic balanced charging control strategy is verified.