An improved J-A model for iron-based soft magnetic composites considering local demagnetization effect

Soft magnetic composites (SMCs), as three-dimensional (3D) isotropic materials can serve as substitutes for traditional laminated soft magnetic materials especially in 3D magnetic circuit devices such as claw-pole motors and power electronics. To utilize and optimize the properties of iron-based SMCs, it is essential to accurately model their magnetic properties at low frequencies and near saturation magnetic flux density. This paper proposes an improved J-A (Jiles-Atherton) model that predicts magnetization in SMCs by considering the influence of internal demagnetization on domain wall motion, incorporating an effective demagnetization factor to adjust the effective field. Simultaneously, a dynamic hysteresis model applicable to SMCs is established for the inter-particle and intra-particle eddy current losses of SMCs. Two iron-based SMC samples with 5 wt% and 7.5 wt% Ni-Zn ferrite content were fabricated via spark plasma sintering (SPS) and tested under static and dynamic magnetization of in-service conditions. A comparative analysis of experiments and simulations shows that the improved model accurately predicts hysteresis loops and iron losses, with relative errors under 8 % in the 10–100 Hz frequency range, which improvements are especially noticeable at the near saturable area of the simulation loop.