Modeling and Performance Evaluation of Inductive Couplers for Pulsed Current Injection

Pulsed current injection (PCI) is an important conducted susceptibility testing technique. In several related standards, the short-circuit current waveforms of the pulse generators are defined and the coupling methods are mentioned, whereas the performance of the couplers and the injected electrical quantities have not been clearly defined. Therefore, the couplers with different performance criteria would lead to various injected electrical quantities and consequently rather different experimental effects. This article focuses on modeling and quantitatively evaluating the performance of inductive couplers. The key issue in modeling is how to measure the frequency-dependent characteristics of ferrite cores under high-power operating conditions (up to several kA); therefore, an impulse injection method is proposed and validated by a 400-kV pulse generator with the rise time of 5 ns to measure the frequency-dependent characteristics of ferrite cores. The validation test confirms that the bandwidth of the modeling procedure can cover the bandwidth of interest for PCI tests. The criteria of performance evaluation for inductive couplers are proposed in frequency domain as well as in time domain. In addition, the criteria are compared for two inductive couplers with different ferrite materials, which shows that the criteria are not only significant in comparing and selecting couplers quantitatively, but also of critical importance in the design phase.