Katarzyna Fonteyn

Improving Loss Properties of the Mayergoyz Vector Hysteresis Model

We present a new method for improving the magnetic loss properties of a certain class of isotropic vector hysteresis models based on the Mayergoyz model. We show that the Mayergoyz model possesses the necessary features for representing vector hysteresis but falls short of satisfying the loss property under rotating magnetic fields with magnitudes close to saturation. Therefore, we propose a new simple method to improve the loss property of the Mayergoyz model while keeping the essential features of the model. The method is based on removing the irreversible process persisting at saturation and hence correcting the magnetization behavior of the Mayergoyz model. We present thorough discussions about the properties of the new model as well as numerical results supported by experiments.

FEM for Directly Coupled Magneto-Mechanical Phenomena in Electrical Machines

A directly coupled magneto-mechanical model is proposed for simulating the effect of the magnetostriction and electromagnetic stress in iron. The model is based on the general balance laws of electromagnetism, mechanics, and continuum thermodynamics. It is implemented in 2-D by using a conforming finite element method for the magnetic vector potential and the displacement field. The method is applied to two different types of induction machines.

Contribution of Maxwell Stress in Air on the Deformations of Induction Machines

Deformations in a cage-induction machine are investigated with simulations. The contribution of the Maxwell stress in the air gap and coil regions of the machine on the deformation is studied by comparing results obtained with and without inclusion of the stress into the calculation. The work attests the acceptability of an energy-based magneto-mechanical model for a 2D mesh of two different rotating electrical machines.

Magnetomechanical coupled FE simulations of rotating electrical machines

Purpose – The purpose is to implement and compare different approaches for modelling the magnetostriction phenomenon in iron sheet used in rotating electrical machines. Design/methodology/approach – In the force-based approach, the magnetostriction is modelled as a set of equivalent forces, which produce the same deformation of the material as the magnetostriction strains. These forces among other magnetic forces are computed from the solution of the finite element (FE) field computation and used as loads for the displacement-based mechanical FE analysis. In the strain-based approach, the equivalent magnetostrictive forces are not needed and an energy-based model is used to define magnetomechanically coupled constitutive equations of the material. These equations are then space-discretised and solved with the FE method for the magnetic field and the displacements. Findings – It is found that the equivalent forces method can reproduce the displacements and strains of the structure but it results in erroneo...

A posteriori iron loss computation with a vector hysteresis model

Purpose – The purpose of this paper is to find out how to model iron losses in electrical machines accurately and efficiently.Design/methodology/approach – The starting point was a previously developed vector hysteresis model that was designed and incorporated into the 2D time‐stepping finite‐element (FE) simulation of induction machines. The developed approach here is a decoupling between the vector hysteresis model and the 2D FE model of the machine. The huge time consumption of the incorporated hysteresis model required some new approach to make the model computationally efficient. This is dealt with through an a posteriori use of the vector hysteresis model.Findings – In this research, it was found that the vector hysteresis model, although used in an a posteriori scheme is able to accurately predict the iron losses as far as these losses are small enough not to affect the other operation characteristics of the machine.Research limitations/implications – The research methods reported in this paper dea...