Identification techniques of functions approximating magnetization characteristics of synchronous machines.

Purpose – The aim of the paper is to present the approximation methods of the magnetizing characteristics of the salient pole synchronous machines with the fundamental MMF harmonics. Design/methodology/approach – The energy based approach is used to formulate a set of the functions approximating the magnetic flux linkages versus an equivalent magnetizing current in the circuit model of the synchronous machine. The estimation of the approximation functions parameters is based on the results of the field calculations. Findings – The identification of the approximation functions is effective and significantly simpler on the basis of the magnetic field co-energy function, than on the basis of the magnetic flux linkages. Research limitations/implications – The magnetic field co-energy function determined by FEM is sufficient for simplified calculations of the magnetic parameters occurring in the circuit models of the electrical machines with nonlinear core. Practical implications – The paper provides guidance for the circuit modelling of the multi-pole generators and motors under conditions of magnetic saturation. Originality/value – A paper has succeeded in determining the internal magnetic characteristics of the synchronous machine with a salient pole rotor. [ABSTRACT FROM AUTHOR]