Design Of AC Charging Pile System For Electric Vehicle And Research On Active Filtering

With the development and progress of science and technology,problems such as energy shortage and environmental pollution have attracted people's attention.Therefore,the electric vehicle industry driven by clean energy and environmentally friendly has been rapidly developed.As an indispensable part of the electric vehicle industry chain,the development of electric vehicle supporting charging facilities and the electric vehicle industry promote each other and restrict each other.In this paper,the research and design of a new type of AC charging pile with harmonic control function is carried out based on the control and harmonic suppression in the AC charging of electric vehicles.This thesis first analyzes the functional requirements of electric vehicle charging and determines the system structure of AC charging piles.Through the modular design idea,each functional module of the AC charging pile control system is designed based on the STM32 processor STM32F103VET6.The hardware circuit design including the controller unit,the transaction settlement unit,the human-computer interaction unit,the electrical parameter measurement unit,the charging guide unit,the network communication unit and the preparation of the corresponding software program.And complete the functional test of the AC charging system.Secondly,aiming at the harmonic and reactive current generated by the electric vehicle during AC charging,this thesis introduces the active filtering technology and studies the single-phase shunt active power filter in the AC charging pile to effectively solve the harmonic suppression.The discrete-type sliding window Fourier transform method is used to detect the harmonics and reactive current in the AC charging process.The detection method has good transient performance and high precision.Then the double closed-loop active filter control system is designed,and the inner loop adopts PI.The control and the repetitive control jointly adjust the current to realize accurate tracking and control of the high-frequency harmonics in the charging current,and improve the dynamic response of the system;the outer loop adopts PI control to stabilize the DC-side voltage of the active filter;The small single-phase space voltage vector modulation method is used for PWM control signal modulation.The simulation model is built with MATLAB/SIMULINK simulation software,and the effects of harmonic suppression and reactive current compensation are analyzed and verified.Finally,this thesis tests and verifies the designed AC charging pile system.The experimental results show that the AC charging pile function module designed by thissubject is complete,reliable and easy to operate,and meets the design requirements.