Variable-Temperature Magnetic Properties Measurement and Improved Temperature-coupled Bertotti Core-Loss Modeling of Fe-Based Amorphous Alloy

Fe-based amorphous alloys are important for medium- and high-frequency magnetic devices. This work investigates the variable-temperature magnetic properties and core loss of Fe-based amorphous ribbon strips and develops a temperature-coupled Bertotti model for loss prediction under coupled frequency–temperature conditions. In this paper, the magnetic properties and core loss of Fe-based amorphous alloy were measured from 25 to 100 °C and from 50 Hz to 3 kHz by the Epstein-frame method. The experimental results show that temperature significantly affects the magnetization and loss characteristics. With increasing temperature, the magnetization curve shifts rightward, the peak permeability increases, and the hysteresis-loop area as well as the total loss generally decreases. Based on the Bertotti loss-separation framework, a temperature-coupled core loss model is established and temperature dependence is incorporated at the loss components. The accuracy and effectiveness of the proposed model are verified using experimental results under varying temperatures and a wide frequency range.