An Analytical Finite Integration-Based Approach for Thick Laminations Eddy-Current Losses Calculation

Electrical steel sheets are widely used in the manufacture of electrical machine cores, and the associated electrical and magnetic losses contribute significantly to the efficiency of electromagnetic energy conversion devices. In recent years, many studies have focused on developing models for calculating hysteresis losses, while models focusing on induced current losses have received less attention. Although thin sheets are generally used for most steels used in the manufacture of electrical machine cores, there are applications where mechanical properties are paramount. In these cases, relatively thick sheets are employed, such as in the rotor poles of high-power synchronous machines. Generally, the classic model for determining eddy current losses in thin electrical steel sheets is used but it is inaccurate for thick laminations, as it neglects the return current path, assuming an infinite width-to-thickness ratio. In this paper, a simple analytical model that incorporates currents in the thickness direction is proposed, overcoming this limitation. The model is derived from the application of a proposed numerical method based on the Finite Integration Technique used for the calculation of eddy-current losses for several different width-to-thickness ratios. Simulation results are compared to experimental ones, demonstrating accuracy of the proposed approach.