THEORETICAL AND EXPERIMENTAL INVESTIGATIONS OF THE CROSSMAGNETIZING PHENOMENON IN SATURATED SYNCHRONOUS MACHINES
Date
1989-10
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Degree Level
Masters
Abstract
In recent studies of the saturation effect in synchronous machines, there has been an increasing recognization of the important role of the magnetic coupling between the direct- and quadrature-axis (the cross-magnetizing phenomenon) in the analysis of saturated synchronous machines. In this context, it has been noticed that there are large discrepancies between their measured and calculated steady-state characteristics. This has been attributed to ignoring this magnetic coupling effect in the steady-state, two-axis (direct and quadrature-axis) frame models of these machines.
This thesis investigates the various approaches of representing saturation in the two-axis frame models of synchronous machines. In particular, the concept of the magnetic coupling between the two axes of synchronous machines is demonstrated. A modified two-axis frame model, in which the effect of the cross-magnetizing phenomenon is included, is used in the investigations of the steady-state performances of four synchronous machines of various designs. The active and reactive power/load angle curves of these machines are obtained experimentally and analytically. The accuracy and the universality of this new model and the importance of the inclusion of the cross-magnetizing effect in such a model are thus verified.
The thesis also presents some new techniques which have been developed through the course of the research work. For determining the various saturation factors of salient-pole synchronous machines, a method for calculating the open-circuit characteristic curves in the intermediate axes of these machines is developed. This method can also be applied in calculating the cross-magnetizing effect of the salient-pole synchronous machines. Moreover, an accurate method is proposed for determining the armature leakage reactance of synchronous machines, which is needed for the determination of the machine per unit field current
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Degree
Master of Science (M.Sc.)
Department
Electrical Engineering