Design Of 20kW Electric Vehicle Charging Module

With the development of the global economy,the global energy consumption is huge,and the environmental problems that accompany it are becoming more and more serious.Electric vehicles are the new energy-saving and environmentally-friendly vehicles.In recent years,they have received strong support from the state.The development of electric vehicle charging modules and the popularization of electric vehicles complement each other.Designing high-efficiency,high-power density,safe and reliable,and versatile charging modules is a hot research topic.In this paper,the two-stage topology of VIENNA Topology Power Factor Correction(PFC)rectifier circuit and LLC full-bridge resonant converter is selected to meet the power factor requirements of the grid for power grid equipment.The output voltage range covers 200V-750V to meet the versatility requirements of the charging module.The VIENNA rectifier module has a three-level topology and an interleaved parallel topology used in the LLC full-bridge resonant converter,which can reduce the voltage stress of the switching tube and facilitate the selection of the switching tube.The application of the LLC soft switch reduces the switching loss of the DC-DC converter,which further increases the operating frequency of the converter and improves the overall power density of the charging module.Firstly,this paper introduces the topology selection of rectifier module and DC-DC module respectively.By analyzing the design requirements of electric vehicle charging module,the two-stage topology of VIENNA rectifier and LLC full-bridge resonant converter is selected.Compared with the different control strategies of the VIENNA rectifier based on the natural frame,combined with the engineering practice,the control strategy of the carrier phase shift absolute current value based on the abc natural frame is selected.Secondly,the causes of the midpoint voltage fluctuation of the VIENNA rectifier DC bus are analyzed in detail,and the method of adding voltage deviation compensation in control loop is adopted to eliminate the DC voltage deviation of the midpoint of the DC bus.The model of VIENNA rectifier is established in the abc frame,the small signal transfer function of the main circuit is determined,and the compensation functions of voltage loop and current loop are designed.The theoretical feasibility is proved by simulation.Based on the First Harmonic Approach(FHA),the steady-state gain transfer function of LLC full-bridge resonant converter is established,and the design principle of resonant parameters is analyzed and the simulation is built in Simulink.The simulation results show that a wide range of voltage outputs LLC full-bridge resonant converter can be realized at full load,and the switch tube is ZVS open.Finally,the hardware design of the experiment and the DSP control program design are introduced,and an experimental prototype of the VIENNA rectifier module is built.