Uncertainty Analysis in the Measurement of Switching Losses in GaN FETs Power Converters

This paper analyses the method for measuring the switching losses in Gallium Nitride (GaN) Field Effect Transistors (FETs) employed in highly efficient power electronics applications, particularly in DC-DC converters. In this regard, the switching losses are measured through the integration of the product of the voltage multiplied by the current during the turn-on and turn-off intervals of the switching process. The objective of this analysis is to identify, model, correct/minimize and quantify the main contributions to the switching losses’ measurement uncertainty following a top- down approach. First, a set of general specifications for a suitable test bench is given. Subsequently, the distortion of the oscilloscope-probe system and the influence of the current shunt is studied along with a method for correcting the waveform distortion. Then, based on the model describing the general measurement method, the individual sources of uncertainty are stripped down, giving guidance regarding how to estimate each of them. Finally, such individual contributions to the switching losses measurement uncertainty are propagated and combined following the guidelines of the "Guide to the Expression of Uncertainty in Measurement".