Fabien Sixdenier

Circuit simulation software is routinely used in power electronics to analyze systems with magnetic cores exhibiting significant hysteresis behavior. This paper presents the implementation of the Energy-Based Hysteresis Model (EBHM) in LTspice to account for hysteresis in magnetic cores of inductors. The model is validated via transient simulations of a DC/DC buck converter, comparing results with experimental measurements across various input voltages, frequencies, and duty cycles. While the model accurately predicts average current, discrepancies in current ripple are observed, attributed to core-to-core variability in ferrite materials. The EBHM implementation offers a significant computational advantage, with simulation times remaining under 10 seconds even for highly saturated cases. The model’s robustness and potential for extension to dynamic effects (e.g., eddy currents) are discussed, along with its applicability to other power electronics topologies.

The magnetizing inductance of the medium frequency transformer (MFT) impacts the performance of the isolated dc-dc power converters. The ferrite material is considered for high power transformers but it requires an assembly of type “I” cores resulting in a multi air gap structure of the magnetic core. The authors claim that the multiple air gaps are randomly distributed and that the average air gap length is unpredictable at the industrial design stage. As a consequence, the required effective magnetic permeability and the magnetizing inductance are difficult to achieve within reasonable error margins. This article presents the measurements of the equivalent B(H) and the equivalent magnetic permeability of two three-phase MFT prototypes. The measured equivalent B(H) is used in an FEM simulation and compared against a no load test of a 100 kW isolated dc-dc converter showing a good fit within a 10% error. Further analysis leads to the demonstration that the equivalent magnetic permeability and the average air gap length are nonlinear functions of the number of air gaps. The proposed exponential scaling function enables rapid estimation of the magnetizing inductance based on the ferrite material datasheet only.

Some soft magnetic materials are strongly dependent of the temperature, because of their low Curie temperature. To be able to predict their behaviour in electrical devices, hysteresis models able to take into account the temperature are needed. The vector play static hysteresis model is an interesting hysteresis model that can be modified to be able to take into account the thermal behaviour. In this paper, the temperature is taken into account in this last model through its parameters. The variations of some parameters with temperature are mainly issued from numerical interpolation and specific assumptions. Simulation results are compared to measurements and discussed.

Some soft magnetic materials are strongly dependent on the temperature, because of their low Curie temperature. In order to predict their behavior in electrical devices, engineers need hysteresis models able to consider the temperature. This paper is an attempt to consider the temperature in an existing model of static hysteresis through its parameters. Variations of some parameters with temperature are issued or build thanks to the literature. At the end, all needed parameters have an analytical law versus temperature. The simulation results are compared with measurements and discussed.

The aim of this study consists in modeling the magnetic behavior of a nanocrystalline material, taking into account temperature variation. Indeed the development of power electronic embedded systems leads to increase the operating temperature range. Besides nanocrystalline material is used more and more in such systems, so temperature influence is a key point in the magnetic component design.