Lithium Battery Charging Method Research Based On Grey Model And Design Of On-board Charger

In today's energy saving and low-carbon environment,the electric car with its advantages of cleaning and use of renewable energy is becoming a hot spot of current research.The lithium iron phosphate battery has a great advantage in specific energy,specific power,long cycle life and price,so it will become the best choice for electric vehicle power supply in the future.Because of limited power capacity and slow charging speed,battery was completely unable to meet the requirements of people to travel long distances.That directly affects the promotion of electric cars,which is not conducive to the innovation of the country's car industry and the need of environmental protection.So the power battery recharge quickly becomes the research hot spot at the present stage in China.This paper summarizes the present main charging technology,analyzes the reasons of influence the battery fast charging,and proposed to speed up the charging method.Due to the complex electrochemical characteristics of battery,it is difficult to build a precise model for describing the LI-ion battery behavior.The grey system model is put forward to solving battery model problem,and elaborated the grey model in detail.The mathematical steps of the establishment of gray model are also given.Monomer battery charging and discharging device is developed.Main circuit structure and process of the charging and discharging are analyzed in detail.At the same time,the paper also puts forward a kind of recyclable energy discharge circuit,which can effectively avoid the discharge energy in the process of discharging.According to the experimental requirements,the charging and discharging device can be designed a variety of charging ways of function,and U disk can be used to save data for,TXT,word,excel.In the process of power battery charging,overcharge and is existed.On the basis of power battery grey model,charging end determination techniques based on grey model is proposed.The power battery charging system is a nonlinear time-varying system.The traditional PID cannot meet the requirement of the high precision of control,so gray PID control technology are put forward to solve this problem.Results show that grey PID control precision is higher.Finally,according to project requirements,on-board charger is designed.It mainly is divided into the hardware part and software part.The hardware includes mechanical and electrical charging road,charging main circuit design,key components and selection,control circuit design.This paper gives detailed design parameters of the circuit principle diagram,and also gives the object graph.Software part includes the general structure design of control system software,peripheral hardware programming,charging the main program design,etc.Peripheral hardware equipment program including sampling program design,protection design,IGBT driver design;Charging program includes:main program and the PWM interrupt subroutine.