Iron-Loss Model With Consideration of Minor Loops Applied to FE-Simulations of Electrical Machines

The accurate prediction of iron losses in soft magnetic materials for various frequencies and magnetic flux densities is eminent for an enhanced design of electrical machines in automotive applications. For this purpose different phenomenological iron-loss models have been proposed describing the loss generating effects. Most of these suffer from poor accuracy for high frequencies as well as high values of magnetic flux densities. This paper presents an advanced iron-loss formula, the IEM-Formula, which resolves the limitation of the common iron-loss models by introducing a high order term of the magnetic flux density. Furthermore the IEM-Formula is extended in order to include the influence of higher harmonics as well as minor loops. In line with this a detailed study of minor loop loss behavior is presented. Exemplarily, the iron-loss formula is utilized to calculate the iron losses of a permanent magnet synchronous machine for the drive train of a full electric vehicle.