Impact of Dynamic Cross-Saturation on Accuracy of Saturated Synchronous Machine Models: Impact of Dynamic Cross-Saturation on Accuracy of Saturated Synchronous Machine Models

Cross-saturation effect in synchronous machines has been a subject of considerable attention in recent years. Inclusion of cross-saturation in the machine model has two consequences. The first one, called here 'steady-state cross-saturation', consists of dependence of the steady-state d-q magnetizing inductances on the currents in both axes. The second one, termed here 'dynamic cross-saturation', is the existence of nonzero elements in the system matrix, that describe cross coupling between d- and q-axis. Dynamic cross-saturation appears in all saturated machine models, regardless of the set of state-space variables, with the exception of the winding flux linkage state-space model. The aim of this paper is to compare behaviour of various models when dynamic cross-saturation is neglected. It is shown that the impact of dynamic cross saturation on accuracy depends on the selected set of state-space variables. In majority of cases omission of dynamic cross saturation has practically non impact on accuracy. These models therefore fully describe the complete saturation effect by means of only continuous variation of the d-q axis magnetizing inductances.