Time Calibration Method for Near-Field Based Reconstruction of Current in Power Electronic Component

Abstract

The characterization of power modules is currently limited by the intrusiveness of conventional voltage/current measurement methods, especially for Wide BandGap (WBG) components such as GaN or SiC. Near-field, contactless measurement techniques provide a relevant alternative, as they are non-invasive and suitable for measuring fast transient phenomena. However, reconstructing time-domain signals from near-field measurements requires precise knowledge of the time delay introduced by the probe. This condition is essential for accurate temporal alignment between the actual electrical quantities and the reconstructed signals. This paper proposes a calibration method for extracting and compensating the time delay of a near-field probe. The validity of the approach is demonstrated by the time-domain reconstruction of a current in a microstrip line and the reconstruction of the drain current of a GaN transistor during fast switching. The study also assesses the impact of probe-trace distance uncertainty on the reconstructed signal.