Prediction of iron loss in rotating machines with rotational loss included

Iron loss prediction is an important issue in both design and analysis of electrical machines. Because of their complicated structure, flux distribution, and rotational variation of flux, it is difficult to predict the iron loss in a machine exactly. This paper studies the iron loss in the core of rotating machines in which the rotational field is dominant, using the finite-element method. For electrical machines in practical operation, additional iron losses due to the appearance of rotation of flux vectors and harmonic flux densities make the calculation results deviate from the measured data. We have revised the method to account for these excess iron losses by considering both the influences of flux vector rotations and flux density harmonics. Calculation and experiments on two kinds of interior permanent-magnet synchronous motors have verified that our method produces results that agree well with the experimental ones. Index Terms--Electric machines and transformers, magnetic losses.