Effect of mechanical stress on the magnetic loss of electrical steel sheets is analyzed utilizing the statistical loss theory. The focus of the study is on the variation of the excess loss component with the applied stress and its correlation with the hysteresis loss. The model and its correlation are validated by performing comprehensive measurements at various combination of induction levels, frequencies and stresses. It is found that the excess losses can be modeled with sufficient accuracy by their correlation with the hysteresis losses over a wide range of stresses, frequencies and flux densities.

A novel approach for predicting magnetic hysteresis loops and losses in ferromagnetic laminations under mechanical stress is presented. The model is based on combining a Helmholtz free energy -based anhysteretic magnetoelastic constitutive law to a vector Jiles-Atherton hysteresis model. This paper focuses only on unidirectional and parallel magnetic fields and stresses, albeit the model is developed in full 3-D configuration in order to account also for strains perpendicular to the loading direction. The model parameters are fitted to magnetization curve measurements under compressive and tensile stresses. Both the hysteresis loops and losses are modeled accurately for stresses ranging from -50 to 80 MPa.

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Cutting the electrical steel sheets to form the shape of the stator and the rotor affects the magnetic properties of the sheets. The increase of the magnetic losses as well as the drop of the magnetic permeability can impact on the design of electrical devices. This paper investigates this deterioration effect on the optimal design of the stator of a high-speed permanent magnet synchronous motor. The deterioration due to punching is phenomenologically analyzed based on measurement of strips of steel sheets with various widths on an enlarged Epstein frame. The losses are computed with a Bertotti model whose coefficients depend on the width of the sheets. The optimization of a synchronous machine is then carried out with this magnetic losses model.

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