Development Of Pulse Source For EMC Sensitivity Testing Of Electric Vehicle Charging Pile

In the context of global warming and energy crisis,the development of electric vehicles has become an important measure for energy conservation and emission reduction in countries around the world.Electric vehicles are vehicles powered by electric energy.Therefore,charging piles that power electric vehicles are indispensable devices.Outdoor charging piles are very vulnerable to lightning weather(inductive lightning or direct lightning surge impact).The discharge process of lightning is actually a fast transient pulse group.Such pulse group electromagnetic interference signals can cause damage to electronic devices,malfunctions,and logic failures through coupling channels such as gaps,holes,and cables,which will seriously affect the normal operation of the charging pile.Therefore,in order to test the electromagnetic compatibility(EMC)sensitivity of the charging pile before leaving the factory,this project has designed a high-voltage pulse source that simulates the lightning environment.The pulse source index designed in this paper:The rising edge is less than 20 ns,the voltage peak value is 50 k V,the minimum pulse interval time is 100μs,and the multiple double exponential pulse groups are continuously adjustable in steps of 10μs.The specific work content is as follows:Using the principle of linear superposition,a circuit topology using multiple delay discharges is proposed,and a design scheme for continuously adjustable multiple pulse groups is determined.The composition of the pulse source is introduced,and the scheme of using capacitive energy storage as the energy storage method,hydrogen thyristor as the high-voltage switchgear and high-voltage DC power supply as the primary energy source is determined.Perform Matlab/Simulink simulation analysis on the principle of capacitor energy storage discharge pulse formation,and obtain the relationship between output pulses and different loop parameters;analyze the working principle of hydrogen thyratron,calculate parameters and select devices;for multiple pulse groups The parameters are analyzed and the appropriate parameters are obtained through Matlab/Simulink simulation.The main circuit of high voltage DC power supply is designed,including EMI filter circuit,rectifier filter circuit,full bridge inverter circuit,high frequency transformer and voltage doubler rectifier circuit.EMI filter circuit can suppress electromagnetic interference caused by AC lines and electronic devices;rectifier filter circuit,full-bridge inverter circuit,high-frequency transformer and voltage doubler rectifier circuit can achieve DC/DC voltage adjustment.The pulse source control system is designed,including DSP control and host computer control,which mainly realizes the timing control module,the key modulation module,the PID algorithm module and the RS-485 module for mutual communication.The upper computer transmits the number of pulse source channels,frequency size and pulse interval time to the DSP to realize the pulse source with adjustable output channels,frequency and interval time;it can be judged whether there is an overcurrent state through remote control to protect the safety of the system.In the pulse source prototype test,anti-interference protection measures are designed for the interference problem of the pulse source itself;test the pulse generation loop,including experimental tests with different numbers of channels,different intervals,and different frequencies.The test results show that the rising edge is less than 20 ns,the voltage peak value is 50 k V,and the timing control of the pulse source system is realized,making the simulated environment more likely to be a real lightning environment.