Dynamic Simulation of Unbalanced Magnetic Force in Doubly-Fed Induction Machine with Inter-turn Short-Circuited Stator

Abstract

In the presented work, a dynamic model is provided for the wound-rotor induction machines with short-circuited stator winding. Both inter-turn phase-to-ground and inter-turn phase-to-phase short circuit faults are considered in the provided model. The self- and mutual-inductances of the windings of the faulty machine are the parameters of the provided state-space equations. As well as the machine electromagnetic torque and its stator and rotor currents, the waveform of the unbalanced magnetic force (UMF) in the faulty induction machine is predicted in the provided model. The UMF of the faulty machine is expressed by a static function of the machine currents. The parameters of the UMF function are obtained by using the Maxwell definition. The machine inductances and the air gap flux density distribution are obtained by means of winding function method. Since the exact waveforms of the machine turn functions are considered in computation of the air gap flux density, the special harmonics are taken into account inherently in the provided model. Finally, the developed model is verified by means of the time-stepping finite element model.