Magnetic core loss behavior at high fields in magnetic materials

Many induction heating coils use soft magnetic composite materials (SMC) to improve induction heating system performance. In demanding induction heating applications, the core loss in the soft magnetic composite material is one of the critical factors in predicting the reliability of the induction coil using computer modelling. In this paper we have used calorimetry method for experimentally determining core losses in SMCs up to approximate to 1 T magnetic flux densities at a frequency near 150 kHz. This paper contains a discussion on the limitations of current methods for calculating core losses. To address these limitations, a new method for calculating core losses is presented. The results of the core loss measurement did not fit well with traditional core loss models over the full range of magnetic flux densities. A discussion on the different models and a hypothesis for the source of the variation from the models is presented.