Estimating the magnetic characteristics of a salient pole synchronous machine using ampere turns distribution method

This paper presents a simple yet effective method to determine the flux density-magnetic field intensity (B-H) characteristics of the magnetic material used in a salient pole synchronous machine (SPSM). This is achieved by distributing the magnetic field intensity, H, in the different parts of SPSM using 2D Finite Element (FE) simulations and theoretical calculations. The distribution is based on the open circuit characteristics (OCC) of an actual SPSM. The method avoids complicated optimization methods and can be used in conjunction with commercial finite element (FE) softwares, where implementing such optimization techniques may be difficult. The method requires only an initial estimate of the B-H characteristics using a default core material provided by the software. The procedure will be useful for simulating SPSMs or other electric machines whose magnetic material properties are approximately known but has changed with long usage and aging. Theoretical calculations complimented with simulation and experimental results prove the effectiveness of this new method.