Circuit and Electromagnetic Modeling of Bulk Current Injection Test Setups Involving Complex Wiring Harnesses

In this work, an enhanced model of injection probes for bulk current injection (BCI) is proposed, allowing for circuit simulation of BCI test setups involving complex wiring harnesses. Accuracy of the proposed model is assessed by means of electromagnetic (EM) full-wave simulation of different wiring structures comprising a large number of conductors. To this end, a virtual calibration setup, including an EM model of the injection device mounted on the calibration jig provided by the probe manufacturer, is preliminary developed and validated versus measurement data. The model is then used to investigate the main factors influencing RF noise injection in practical BCI setups. Particularly, it is used to predict the significantly different levels of noise measured at the terminations of each wire in the bundle during the BCI test, as well as to provide such differences with an explanation in terms of characteristics of the wiring harness, positioning of each conductor in the bundle with respect to the others, equivalent common mode impedance of the terminal networks.