Comparison of Methods for Switching Loss Estimation in WBG Systems

Abstract

Comparing wide band-gap (WBG) devices requires accurate and consistent characterization. One important Figure of merit when selecting a transistor for an application is power loss due to switching. At higher switching frequencies, switching losses become the dominant loss mechanism in hard-switched converters. In the literature, two techniques have emerged for measuring switching losses: 1) the double-pulse test (DPT) and 2) evaluation of a complete converter at varying operating frequencies. This paper compares these two techniques and introduces a third technique, which involves operating the converter in a semi-continuous mode to reduce the impact of thermals on the power loss estimation. As part of this work, an empirical study was conducted to compare these techniques. This study showed that the three techniques produce significantly different switching loss estimates for the same device under test (DUT) at identical operating conditions. This paper demonstrates that DPT is the most accurate method for determining a DUT’s switching losses, despite some known limitations.