| In recent years,the electric vehicle industry has been booming,but due to the restriction of battery and other related technologies,the electric vehicle industry is still not mature,and its corresponding supporting facilities charging pile has also become the current research hotspot.At present,the research of charging pile is faced with the bottleneck of power quality,charging characteristics,charging efficiency and only passive one-way charging.This paper focuses on how to improve the power quality of charging piles and realize the two-way flow of electric energy between the grid and electric vehicles.Charging piles affect power quality by many factors,such as harmonic pollution and so on.The generation of harmonics is mainly due to the traditional rectifier control mode and the main circuit structure is various,which will cause the network side current distortion distortion,so that the power factor is reduced,the DC side output voltage can not achieve stability,which has a great impact on the power quality.The two-way charging and discharging of the charging pile can realize peak reduction and valley filling,reduce the pressure on the power grid,make reasonable use of the electric energy resources,reduce the risk of battery spontaneous combustion,improve the safety of electric vehicles,and also greatly reduce the user's vehicle cost.Firstly,the topological structure,working principle and control strategy of the three-phase AC/DC bi-directional converter are deeply studied.The relevant parameters of the circuit are designed and the mathematical models of the three-phase static coordinate system and the two-phase rotating coordinate system are deduced.It is determined that the voltage space vector(SVPWM)double closed-loop control is adopted in the three-phase AC/DC bi-directional converter,and the PI controller parameters are designed and determined.Then use Matlab/Simulink simulation software to build a simulation model and conduct simulation experiments to verify the feasibility and advantages of the selected strategy.Have carried on the hardware design to the control circuit and adopt TI company TMS320F28335 chip as the control chip,compile the relevant program.Finally,a hardware test platform was built in the laboratory,and the experimental results verified the feasibility of the control method in this paper,which finally realized the two-way flow of electric energy of the charging pile as well as the high power factor and efficient operation. |
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