Experimental Method for Accurate Measurement of High Frequency Bridge Loss

Accurate measurement of power loss in a half-bridge circuit is essential for evaluating the performance of power converters. However, due to the fast-changing nature of voltages and currents in wide bandgap devices like SiC MOSFETs, measuring high-frequency bridge loss using traditional methods is challenging. The initial analysis of a buck converter presented in this article gives an insight of the important parameters to be considered for measurement. This article presents an experimental method to measure high-frequency bridge loss accurately. It requires a precision ammeter in addition to standard laboratory equipment like an oscilloscope and voltage probes with sufficiently high bandwidths. The accuracy of the presented method is validated experimentally using a buck-converter laboratory prototype upto 1.8kW with 1200V SiC MOSFETs. An accuracy of 98.5% is achieved in measuring high-frequency bridge loss using the proposed method.