Design Of DC Charging System For Electric Vehicle Based On ARM

Conventional fuel vehicles have brought great convenience to the way of humans travel.But fuel vehicles consume limited oil resources and release a lot of exhaust.It causes environmental pollution and energy crisis to aggravate step by step.It has a serious impact on human survival.Under the pressure of environmental deterioration and energy shortage,it will become a trend to develop electric vehicles of clean and environmental protection in order to make the automobile industry continue.However,the main difficulty in the development of electric vehicles is the rapid charging of batteries.The main research content of this thesis is to design an efficient and fast DC charging system for electric vehicles.It is important for the development of the automotive industry.The present situation,research background and significance of the domestic and foreign research and development of electric vehicles are discussed in the thesis firstly.And the structure,working principle,battery model of lithium iron phosphate battery,common charging method used in lithium battery,stop charging method and charging factor also are discussed in the thesis.An improved three-stage charging method is studied by comparing the traditional methods.And the stop and negative pulses in the charging process can effectively reduce the polarization reaction of lithium battery during charging.Secondly the thesis carries out the whole design of the charging system and determines the main charging circuit.Rectification,filtering,topology,high-frequency transformers are analyzed in detail.A control system with STM32F767 as the core and a monitoring circuit for lithium battery parameters to monitor the internal temperature,current and voltage in real time are designed in the thesis.Finally,an experimental system is established to verify the feasibility of the improved three-stage charging method in the thesis.And the upper computer system is designed,which can monitor the parameters of the charging system.This system verifies the feasibility of improved method of three-stage charging by actual battery charging effects.The experimental results show that the method can shorten the charging time and improve the charging efficiency.