Induction Machine with Combined Star-Delta Stator Winding in Parallel Configuration

A type of induction machine with a combined star-delta stator winding in parallel configuration was analyzed by means of numerical simulations based on lump parameter and finite element method models. The use of a combined star-delta winding enables suppressing selected higher spatial harmonics of the magnetic flux density in the air gap of the machine and, thus, reducing the energy losses and improving the energy efficiency of the machine. The effect of the ratio between the number of turns in the delta-connected winding and that in the star-connected winding on suppressing or eliminating selected higher spatial harmonics of the magnetic flux density in the air gap of the induction machine was investigated in more detail. An experimental machine was designed and built and results obtained by numerical simulations were experimentally verified.