Research On New Energy EV Charging Technology

With the development of China's economy and the improvement of people's living standards,automobiles have become the main means of transportation for people's travel.With the increase of the number of cars,the problems of environmental pollution and primary energy crisis have been caused,and new energy electric vehicles can effectively solve them.Traditional cars pollute the environment and alleviate primary energy depletion.The new energy electric vehicle charges the battery in the vehicle through a dedicated charging device.During the driving process,the battery is supplied with energy through the battery in the vehicle,and the battery obtains the electric energy mainly through the charging facility.This paper mainly analyzes the charging pile and the vehicle charger in the charging facility and its topology circuit structure and control method,which is of great significance for achieving high efficiency,high power density,good reliability and prolonging the service life of the battery.First,the DC charging pile was analyzed.At present,most of the internal rectification structures of DC charging piles at home and abroad adopt three-phase voltage type rectifiers.The PI control method can not realize the current without static control and the anti-interference ability.This paper adopts the quasi-proportional resonance SVPWM control method.The simulation results show that The control method realizes the static tracking of the input current to the command current and has good anti-interference ability.At the same time,the paper also analyzes the application of the three-phase current-type rectifier to the DC charging pile,using the current outer ring and the current inner ring.Dual current loop control method.The simulation analysis shows that the unit power factor is realized by three-phase CSR,the harmonic content of the grid side is 1.31%,the output voltage of the DC side is smaller than the voltage power supply,the adjustable range is large,and the ripple ripple is small.Then,a low-power electric vehicle charger(car charger)is analyzed.The on-board charger usually adopts a series structure of front-end AC-DC and back-end DC-DC.The single-phase Boost-PFC topology circuit has problems such as large switching tube stress,large input current ripple,large current stress on the output side capacitor,and limited power level.In this paper,the front end of the car charger uses a two-phase interleaved Boost-PFC circuit,and the back end uses a half-bridge LLC resonant converter.Through theoretical and simulation analysis,the topology can reduce the stress of the switching tube,reduce the input current ripple,reduce the current stress on the output capacitor and soft-switch technology,reduce the power loss,improve the power density and Achieve good power quality within a certain output range,thus effectively extending the service life of the battery.Finally,a 1.5kw car charger experimental prototype was designed.The experimental results show that the charger can achieve higher power factor in the voltage input range of the AC side.The performance of the experimental prototype is good in the range of 70-105 V output voltage..When the switch operates near the resonant frequency of 100 KHz,the LLC resonant converter realizes the ZVS of the switching transistor and the ZCS of the diode,and the working performance is optimal.