Power loss measurement system for soft magnetic materials in megahertz frequencies

Abstract

Soft magnetic materials play a key role in developing integrated and miniaturized power electronics. However, it is still challenging to accurately evaluate the high-frequency (MHz) power loss of soft magnetic materials, which determines the energy efficiency of power electronics. In this paper, we firstly trace the high-frequency error origination in traditional electrometric method and propose a two-step calibration method for the system to compensate the phase angle discrepancy between exciting current and induced voltage. The first-step calibration eliminates the phase angle discrepancies caused by propagation delay of current and voltage probes, while the second-step calibration compensates residual phase angle discrepancies. A calibration factor k is defined to determine whether the second-step calibration is needed. The experimental results demonstrate that the system’s phase discrepancy is compensated within 0.13°, enabling power loss measurement frequency up to 20 MHz that much higher than present apparatus. Our results will facilitate the development of high-frequency soft magnetic materials and promote the miniaturization of power electronics.