Research On Charging Efficiency Of Electric Vehicle And Design Of AC Charging Device

Due to the promotion of environmental protection policies and the progress of technologies related to electric vehicles,the popularity of electric vehicles in China has increased year after year.Unlike traditional fuel vehicles,electric vehicles supplement energy by charging.In the process of charging,the change of AC and DC and the conversion between electric energy and chemical energy will cause inevitable power loss.At present,China has the largest number of electric vehicles in the world.The energy waste caused by the charging loss of electric vehicles cannot be ignored.Therefore,in order to promote sustainable development and reduce energy consumption,it is of great significance to study the charging efficiency of electric vehicles and design an AC charging device with adjustable charging current through charging experiment and mathematical model analysis.Through several groups of different charging experiments,this paper studies and analyzes the charging characteristics and charging efficiency under different charging modes.According to the AC charging characteristics of electric vehicles,an AC charging device with adjustable charging current is designed and improved.Finally,through the experimental data collection,the energy loss on the charging cable is studied by using MATLAB software and mathematical tools.In the research,I understand the characteristics and charging principle of electric vehicle charging technology.Four charging methods are selected for charging experiment: AC charging pile charging,DC charging pile charging,battery inverter charging and fuel generator charging.Through the experimental results,the characteristics of several charging methods are analyzed and summarized.It is concluded that in the charging process,the rectification and filtering of AC,the inversion of DC,high current charging and internal combustion engine power generation are the main links causing power loss,and the effective energy utilization rate of each link is calculated.Based on the element characteristics of FET and the charging characteristics of power battery,an AC charging device which can adjust the charging current is designed.The charging device can improve the charging capacity of the electric vehicle battery by adjusting the charging current.Through experiments,a large number of data of surface temperature of charging cable,current intensity flowing through cable and cable resistance are measured.Using the least square method to fit the experimental data,it is concluded that the resistance of the charging cable is basically linear with the surface temperature of the cable,and the cable resistance will increase faster with the increase of charging current.Two BP neural network models are trained,and the cable resistance can be predicted by cable surface temperature and cable current intensity respectively.By comparing the prediction results with the actual detection results,it is proved that the two models can achieve prediction.Finally,the whole work process is summarized,and the next research is prospected.The research on the charging efficiency of electric vehicles and the design of AC charging device in this subject are of great significance to optimize the charging function of electric vehicles,reduce the charging cost,give full play to the advantages of electric vehicles and promote the popularization of electric vehicles in the future.