Noncontact Time-Varying Current Reconstruction for Electromagnetic Immunity Diagnosis in Electric Vehicle Module Injection Port Testing

Traditional noncontact probes fail to meet the time-domain reconstruction requirements for relevant low-frequency signals especially on printed circuit boards (PCBs). In this article, a compact multiloop probe with an accurate simulation model is proposed as an optimized diagnostic tool for electromagnetic immunity tests on electric vehicle modules. The probe with the simulated response coefficient from 1 Hz to 1 GHz can replace traditional current clamp probes for use on PCBs. A validation test, based on a double-exponential waveform with a complex frequency-domain distribution, shows that the reconstructed time-domain current using the simulated response coefficient covering lower frequency band from 1 Hz to 1 MHz is more consistent with the directly measured current with the curve error of 1.522% than that by the measured response coefficient with the curve error of 6.074%. In two real immunity tests of electric vehicle modules, the reconstructed current curves are almost identical to the directly measured current curves by an oscilloscope and a commercial clamp probe with the curve error of 1.007% and 2.444%, respectively. It proves the proposed probe with the simulated response coefficient is a suitable tool for electromagnetic immunity diagnosis at the injection port of electric vehicle modules and is potential to be utilized on the PCBs inside the modules.