Nanocrystalline Powder Cores for High-Power High-Frequency Applications

Abstract

Soft magnetic composites (SMCs) based magnetic cores are attractive in high frequency inductor design. The desired overall core permeability of SMC core can be achieved by adjusting the powder size, addition of insulation material and phosphoric acid, and pressure during the preparation process to reduce the air gap loss and ease the inductor design. The nanocrystalline alloy (Fe-Cu-Nb-Si-B) is an emerging SMC with high saturation flux density and low hysteresis loss, showing potential suitability for SMC based magnetic cores. To date, nanocrystalline alloys are mostly used in form of laminated ribbon for magnetic cores and nanocrystalline powder SMCs have been seldom used in practice. Also, neither experimental validation nor comparison with other commercialized and commonly used SMC cores has been reported. In this paper, the structure and manufacturing process of nanocrystalline powder cores are introduced. The calculation of core loss is defined for the nanocrystalline powder core. The characteristics and performance of the nanocrystalline powder toroidal core are compared with those of existing commercial SMC cores such as Fe-Si powder (X flux), Fe-Ni powder (High flux), Fe-Si-Al powder (Kool Mµ), Fe-Ni-Mo powder (MPP). Experimental results are conducted at frequencies from 100 kHz to 600 kHz to verify the loss calculation and feasibility of this new nanocrystalline powder core.

Estimation of Energy Losses in Nanocrystalline FINEMET Alloys Working at High Frequency

“…Temperature is one important parameter that influences the magnetic behaviour of a material, simply by modifying its magnetic properties: a nonlinear evolution of magnetic parameters (saturation magnetization, relative permeability, coercive field) as function of temperature exists [38][39][40][41][42][43]. Heat dissipation is of paramount importance, as any change In conclusion, in the final form, in order to estimate the total energy losses, it is necessary to determine three coefficients (k h , k e , k a ).…”

Power Losses Models for Magnetic Cores: A Review

“…In the same way, choosing a gapped core (a core with a concentrated air gap) instead of a distributed air gap core will impact its behavior and parameters to calculate; for the first one, gap parameters as length are a priority. For the second one, permeability parameters will be taken into account [ 142 ].…”

High-Power Design Challenges for Differential-Mode EV Universal Battery Supercharger

“…SiC devices enable high power switching at increased frequency; therefore, the magnetic components in the converter also need to rise to this challenge. Nanocrystalline and amorphous metal based materials are being increasingly used in the high power applications [37]- [40]. Other techniques like flux cancellation and IM combined with the improved performance of these materials push the power/frequency limits even further [41].…”