Abstract
This article discusses the modeling of double star induction machines (DSIM). Its main objective is to study the impact of the stator mutual leakage inductance on the modeling of such machines, in steady-state and dynamic operations. For that purpose, experimental and simulation results are conducted on two squirrel cage induction machines with equal ratings. The stator of each machine is specifically conceived with two sets of three phase windings. Spatial shifting θ , between the two stars, is made 0° for the first machine and 30° for the second.
Regarding the machine modeling, the study encompasses three cases. First, the mutual leakage inductance is included. Second, the mutual leakage inductance is considered as a self-leakage inductance. Third, the mutual leakage inductance is simply neglected. However, by defining a couple of parameters (α _k, β _k)an original compact model is developed. The approach applies either in steady state or in transient operation.
In addition, to enhance the accuracy of the modelling process, the effect of magnetic saturation is introduced in the d-q mathematical model of the double star induction machine (DSIM), whatever the electrical shifting between the two stator stars.
Predictions of various electrical and mechanical characteristics have shown the importance of taking into account the mutual leakage fluxes in the DSIM modeling, especially in transient operation. Analysis of simulation and practical results has also confirmed the correct model.