A Method of Including the Effects of Main Flux Path Saturation in the Generalized Equations of A.C. Machines

This paper shows how the effects of saturation of the main flux path can be incorporated in the generalized equations of alternating current machines in which the currents are deliberately chosen as the state variables. In the conventional equations linear magnetic conditions are assumed and the forms taken by these equations in various reference frames are well known. When saturation of the main flux path is taken into account, some parameters have to be modified and additional terms introduced; stator (and rotor) self inductances in orthogonal axes are no longer equal. These are the consequence of intersaturation - sometimes called cross-saturation; a phenomenon which has been mentioned in the literature but has not been subjected to general analysis. New forms of generalized equations are derived and their application to the analysis of induction motor starting transients described.