A nonlinear model for synchronous machines to describe high-frequency signal based position estimators

• Published in: IEEE International Conference on Electric Machines and Drives, 2005 pp. 696 - 703
• Main Authors: De Belie, F.M.L.L., Melkebeek, J.A.A., Vandevelde, L., Boel, R.K., Geldhof, K.R., Vyncke, T.J.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 2005
• Subjects: Magnetic flux; Nonlinear equations; Nonlinear magnetics; Reluctance motors; Rotors; Saturation magnetization; Stators; Synchronous machines; Synchronous motors; Voltage
• ISBN: 0780389875; 9780780389878
• DOI: 10.1109/IEMDC.2005.195799

This paper discusses fundamental equations which can be used in high-frequency signal based position estimators for synchronous machines. For this purpose, a small signal dynamic flux model is presented that takes into account the nonlinear magnetic condition and the magnetic interaction between the two orthogonal magnetic axes. The derivation of this model is based on the relationship between flux and coenergy. The model is given in a complex notation and is used to discuss most high-frequency signal based position estimators that have appeared in the literature. By using the finite element method, the coenergy of a given salient-pole synchronous machine is calculated and from it an estimation is made of the parameters in the proposed model. Through experiments it is shown that, by using the relationship between magnetizing current and flux as modelled in this paper, the nonlinear behaviour of the synchronous machine is quite accurately estimated. Furthermore, the new model is compared with a classical model that neglects mutual saturation effects between quadrature and direct axis windings