Modeling of Induction Machines With Switched Stator Windings
Daniel Scharfenstein, Stephan Schüller, Stefan Quabeck and Rik W. De Doncker
Induction machines are an attractive solution for traction applications. However, a drive system might not be able to reach all requested operating points due to given boundary conditions. Switched stator windings are one possible approach to extend the operating range while retaining the machine design. When using a power-semiconductor based switching unit, switchover under load is possible. It can be realized by consecutive switchover in the phase current zero crossings. In this work, an induction machine model is developed for the analysis of the transient behavior during switchover, where asymmetric winding states occur. The model is based on the winding function approach and the multiple coupled circuit model. It is extended to include rotor skewing, slotting effects and saturation effects. The machine model is integrated into a system model with controller, inverter and switching unit to investigate the mutual influences. The developed model is verified by simulations and measurements with good agreement.