Novel Methods for In-situ Direct Magnetic Loss Measurement in a DC-DC Converter

Abstract

Timing skew between measurement channels can introduce an unacceptable error in power loss measurement, making in-situ magnetic loss measurement one of the most difficult engineering problems. This paper develops a mathematical model and provides two novel methods to realize insitu direct magnetic loss measurement. The mathematical model is first established to study the effects of timing skew on the measured/observed magnetic loss in a DC-DC converter. The first method, called Intersection method, is proposed and analyzed in detail. This method will illustrate how the actual timing skew and actual magnetic loss in circuit can be obtained with the aid of the mathematical model. The second method, called Derivative method, will be shown that it greatly enhances the accuracy and repeatability of the same measurements. The proposed methods are verified in simulation and experimentally validated in a conventional step-down DC-DC buck converter under various operating conditions and design parameters.