Magnetic losses in soft magnetic composites and ferrites under rectangular asymmetric excitation

Magnetic losses in soft magnetic materials subjected to non-sinusoidal excitation are of increasing importance in the design and optimization of power electronic components. Conventional loss models and measurement standards, primarily developed for sinusoidal induction waveforms, often fail to accurately predict losses under pulsed excitation typical of switched-mode power supplies. In this study, a simplified implementation of the Statistical Theory of Losses is applied to two heterogeneous soft magnetic materials: an Fe–Si soft magnetic composite and a Mn–Zn spinel ferrite. Magnetic losses were experimentally characterized under sinusoidal and triangular polarization using a digitally controlled hysteresisgraph-wattmeter. The total losses were decomposed into hysteresis, classical, and excess components, allowing for parameter identification and prediction of loss behavior under symmetric and asymmetric rectangular excitations. The predicted energy losses, derived solely from sinusoidal measurements, show excellent agreement with experimental data across a wide range of frequencies and duty cycles. The proposed method provides a physically based yet computationally simple approach for modeling dynamic magnetic losses in materials relevant to power electronics, facilitating more accurate design of magnetic components under realistic excitation conditions.