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A new 2D-hybrid model in cylindrical coordinates intended for the study of a transient magneto-thermal coupled problem is proposed. This model is used to evaluate the spatiotemporal distribution of temperature in rotating aluminum billets heated by permanent magnets induction-heating device (PMIHD). The proposed hybrid model consists of coupling an exact analytical solution of the 2D magneto-harmonic field to a 2D transient thermal analysis where the temperature dependence of electrical and thermal physical properties of the heated billet is considered. Based on the separation variables technique, the analytical solution of magneto-harmonic problem serves to evaluate the induced current and the resulting power density loss distribution in the nonmagnetic billet. Furthermore, the 2D transient thermal analysis, based on the lumped thermal network model, is developed in radial and axial directions of the heated billet. In order to validate the 2D hybrid magneto-thermal model, the performances of the studied PMIHD are compared with those obtained with Finite Element Method (FEM). [ABSTRACT FROM AUTHOR]

The paper describes an analytical technique for predicting the eddy-current loss in the moving armature of a tubular permanent magnet machine. This loss component is usually neglected in conventional tubular permanent magnet machines since high-order time harmonics in the stator current waveform and space harmonics in the winding magnetomotive force (MMF) distribution are generally considered to be insignificant However, a relatively new topology of tubular permanent magnet machine, sometimes referred to as "modular," has emerged in which the fundamental component of the stator MMF has fewer poles than that of the permanent-magnet armature, the thrust force being developed by the interaction between a higher order MMF harmonic and the permanent magnet field. Thus, the presence of lower and higher order space harmonics in the winding MMF distribution of a modular machine may gives rise to a significant eddy-current loss in the moving-magnet armature. An analytical model is developed to predict the eddy currents which are induced in the magnets, as well as in any electrically conducting supporting tube which may be employed, and to quantify the effectiveness of axially segmenting the magnets in reducing the eddy-current loss. The validity of the developed model, which is also applicable to conventional designs of tubular permanent-magnet machine, is verified by time-stepped transient finite-element analysis (FEA). [ABSTRACT FROM AUTHOR]