Design Of Function Test System For Electric Vehicle Charging Gun

For the past few years,as electric vehicles have grown by leaps and bounds,worries about the charging safety have multiplied.The in-cable control and protective device(IC-CPD)of EV charging Mode Ⅱ is portable because it connects the traditional household socket to the vehicle and provides safety protection.The current IC-CPD functional test system on the market only carries out simple tests on some functions,which has the disadvantages of few test items,low precision,poor versatility and low efficiency.In this thesis,a functional test system for electric vehicle charging guns is designed,which has four parallel automatic test slots,the test items mainly include overvoltage and undervoltage protection,current leakage protection,overload protection,overtemperature protection,open ground protection,control pilot signal,LED status and communication test,etc.The system adopts a modular design and its main functional modules are:low power inverter module,which is responsible for supplying different frequencies and amplitudes of AC voltage to the IC-CPD;central control module,which is responsible for controlling the action of the jig,selecting the test point of the IC-CPD and communicating with the IC-CPD;the network port communication module,which takes charge of the communication between the host computer and each functional module and the remote update of the program;light detection module is responsible for real-time detection of the LED status of the IC-CPD.To test the residual current protection function of the IC-CPD more conveniently and accurately,a high-precision residual current generator is designed in this thesis.The residual current generator outputs high-precision ramping bipolar DC or AC according to the command of the host computer,the AC frequency can be adjusted arbitrarily,the starting point,end point and ramp rate of the output current can be set,and the output port state of the IC-CPD and the residual current protection threshold are monitored.An output current calibration algorithm is designed so that the output current error of this module is less than 0.01mA.In this thesis,the function and performance of the system are tested,and the test results meet the functional testing requirements of the IC-CPD.The system has been applied to the functional testing of many kinds of IC-CPDs,which has the characteristics of complete test function,high precision,strong versatility and high efficiency,ensuring that the control and protection function of each IC-CPD is normal before leaving the factory,which can greatly avoid the charging accident of the electric vehicle.