Design Of LLC Resonant Car Charger

Electric vehicles have the advantages of high efficiency,energy saving,green environmental protection,etc.,and have been strongly supported and promoted by the government,and are increasingly popular.The charger is responsible for the charging management of the electric vehicle battery,which is a key link of the electric vehicle power source,and has been extensively studied by domestic and foreign researchers.Aiming at the problem of high-efficiency charging of electric vehicles,this paper studies a LLC resonant on-board charger to improve the charging efficiency of electric vehicle batteries,reduce energy loss,and increase the safety and reliability of the charger.On the basis of summarizing the topological structure and technical indicators of chargers at home and abroad,the thesis proposes the parameters of chargers.According to the index requirements,a detailed overall system plan was formulated,in which the power factor correction circuit adopted a boost topology,and the charging inverter circuit adopted an LLC half-bridge resonant topology.Based on the system plan,the system hardware and software design is carried out.Specifically,in terms of hardware: for the power factor correction circuit,the circuit working principle,working mode and drive control design are introduced,and the main power and drive control circuit are given.For the charging inverter circuit,the three parts of the LLC half-bridge resonant circuit,charging control circuit,and auxiliary power circuit are introduced.Among them,the LLC half-bridge resonant circuit analyzes the working principle in detail,and the theoretical calculation method of the resonant cavity parameter The key components of power and drive control circuits were analyzed.For charging control,various charging control methods are introduced in detail.In terms of software,it mainly includes: single-chip computer-based programming,Lab VIEW-based visual host computer monitoring software design and upper and lower computer communication protocol design.Then,the design and manufacture of the system schematic diagram and PCB board were carried out.And built a hardware test platform,debug power correction circuit and charging inverter circuit,analyze the problems encountered in the circuit debugging process and solutions,save the key waveform and analyze the meaning of the waveform;for the software platform,debug the charger The operation monitoring gives the operation chart of the upper computer,and the charging efficiency chart is drawn in conjunction with the charging time.Finally,a system experiment was carried out.The experiment showed that the charger works normally,the software and hardware are reliable,and the expected index is reached.