A high frequency core loss measurement method for arbitrary excitations

Recently, point of load (POL) converter are pushed to higher switching frequency for higher power density. As the frequency increases, magnetic core loss becomes a significant part of the total loss of POL converters. Accurate measurement of this part of loss is important for the converter design. And the core loss under non-sinusoidal excitation is particularly interesting for pulse-width modulation (PWM) converters. However, precise measurement is difficult with classical four-wire methods, because of high frequency and non-sinusoidal flux waveform (like triangular flux). In this paper, a new method is proposed for high frequency core loss measurement with arbitrary excitation. The principle is to cancel the reactive power in the core under test with a lossless or low-loss core and reduce the sensitivity to phase discrepancy. By doing this, phase discrepancy induced error can be significantly reduced, and accurate measurement can be achieved for higher frequency than conventional method.