Dual stator winding induction machine drive

A new dual stator winding induction machine drive is described in this paper. The new machine consists of a squirrel cage induction motor having two stator windings wound for 2 and 6 poles which are simultaneously fed from two independent variable frequency power supplies. The proposed drive offers the advantage of simultaneously producing two independent electromagnetic torques which can be controlled to produce any desired combination of output torque. Since each torque component is controlled by an independent set of stator currents a minimum operating frequency can be set for each stator winding and still achieve exactly zero or near zero speed and rated torque operation. This feature is specially important to minimize the negative impact of the stator resistance influence at low speed operation. The drive is well suited for either constant volts per Hz (V/f) or field oriented (FO) operation. The occurrence of circulating harmonic currents, common to traditional dual stator machines, is completely eliminated by the dissimilar pole number in each stator winding.