Research On Three-phase VIENNA Rectifierapplied To Electric Vehicle Charging

As an important part of the future automobile industry,electric vehicles need to have high power factor and low harmonic content when large-scale electric vehicle charging systems are connected to the grid to reduce grid energy loss and reduce grid harmonic pollution.Therefore,the front-stage rectification system of the electric vehicle charging system needs to have a power factor correction function to meet the requirements of high power factor and low current harmonics.This paper focuses on the research of three-phase VIENNA rectifiers that can be used for electric vehicle charging,and completes the following work:(1)The working principle of the three-phase VIENNA rectifier is analyzed.To facilitate the design of the controller,the model expressions are derived under the three-phase stationary coordinate system,two-phase stationary coordinate system,and two-phase rotating coordinate system.(2)For the selection of three-phase VIENNA rectifier power factor correction control strategy,from the perspective of engineering application,the PI double closed-loop control,one-cycle control strategy and average current control strategy in the dq coordinate system suitable for engineering applications,from the control principle,Introduction and analysis of modulation strategy,midpoint balance strategy and controller design.To compare the control effects,a simulation model was built under the Simulink environment,and the three control strategies were simulated and compared.Taking THD and power factor as the main reference indicators,the PI double closed-loop control strategy in the dq coordinate system was selected as the three-phase VIENNA power factor correction Control strategies implemented by the system.(3)Designed an engineering prototype with a rated power of 4.5k W,completed the design of the main circuit,control circuit and protection circuit of the prototype,and drawn a PCB board to build an experimental prototype.Using DSP28335 as the main control chip,the software design of the power factor correction system and the joint debugging of software and hardware are carried out.After testing,the steady-state performance and dynamic performance of the prototype are normal,which meets the design index requirements.