High frequency power loss measurement platform

摘要

Sophisticated techniques are required for getting accuracy in high frequency power losses of magnetic. This paper presents a high frequency power loss measurement platform (full bridge) that provides accurate assessing of losses in magnetic components. This is obtained by a construction of a thermal shunt with radiator to measure the losses of the bridge. An aluminium strip is used as a 'thermal resistor'. Two negative temperature coefficient resistors measure the temperature drop across the aluminium strip. The magnetic device loss equals the DC input power of the platform minus the bridge loss. The copper loss can be estimated while using litz wire. Using litz wire windings with sufficiently low diameter of the strands allows neglecting eddy current losses, thus measuring only DC resistance is enough for calculating of copper losses. It can be checked by an RLC metre if the assumption is reasonable. The proposed approach and platform are verified by realisation and experiments with a full-bridge converter based on SiC switches and operating in frequency range of 50 kHz-1 MHz. The proposed platform can be used for obtaining the frequency dependence of core losses of magnetic materials.