Research And Design Of 6.6kW On-Board Charger For Electric Vehicle

Along with the advancement of economy,more and more cars are used in our daily life,although its appearance has greatly promoted people’s work efficiency and life rhythmand,but the energy consumption and environment problems caused by it are becoming more and more serious.For this reason,the world’s major car companies have joined in the research and design of new energy vehicles.As the guide of new energy cars,the development of electric vehicles can effectively solve the energy and environmental problems,which has immeasurable social value,so it has been recognized and paid close attention by people from all walks of life,and governments of all countries have begun to advocate the development of electric vehicles.As a significant component of the electric vehicle,the vehicle charger is mainly used to charge the power battery.It is required to not only meet the basic power transmission capacity,but also meet the requirements of high efficiency,high performance and high power density,so as to save the space and weight of the electric vehicle and enhance the vehicle’s endurance.The future development trend of car charger is miniaturization,lightweight and high frequency.Because the input end of the car charger is directly connected with the municipal power grid,it will lead to serious distortion of the input current of the power grid side,so it has higher requirements in the design,for instance power factor,harmonic distortion,output ripple and efficiency.Therefore,the design of a car charger with good performance can not only extend the service life of the power battery,but also reduce the harmonic pollution to the power grid and enhance the power quality.What is more important is to reduce the consumption of resources,reduce air pollution,protect the environment and ensure the health of human life.High frequency switching power supply has a variety of topology and control methods,each of which has its advantages and technical defects,so it is very important to choose a suitable topology and control method.At present,the design scheme of vehicle charger is two-stage conversion structure,the former stage is PFC circuit,the latter stage is DC/DC circuit.This paper aims to design a 6.6kw on-board charger.By comparing the advantages and disadvantages of various topological structures of the front and rear stages,and combining with the design index requirements of this project,a circuit topological scheme suitable for this project is finally determined,that is,the former PFC circuit uses interleaved parallel boost topology,and the latter DC/DC circuit uses full bridge LLC resonant topology.Based on the design index of vehicle charger,this paper analyzes the working principle and characteristics of the front stage interleaved parallel boost PFC circuit and the rear stage full bridge LLC resonant circuit in detail.It is determined that UCC28070 is the main control chip of the front stage PFC circuit and ncp1395 is the main control chip of the rear stage LLC resonant circuit.According to the chip manual,the parameter design of the control circuit is carried out,and the software pspice16.6 is used to design the whole circuit.The simulation analysis of the circuit verifies the correctness of the design.Finally,a test prototype of 6.6kw vehicle charger is designed.After the actual test,the working state of the prototype is almost the same as the simulation running state,and the power factor and transmission efficiency can meet the design requirements.Again,the rationality and correctness of the design are proved,which provides a reference for future research and development personnel of related design.